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Import crypto/tls from 1.23.3

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世界 2024-11-17 15:36:06 +08:00
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4
go.mod
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@ -5,5 +5,7 @@ go 1.20
require (
github.com/sagernet/sing v0.5.0
golang.org/x/crypto v0.29.0
golang.org/x/sys v0.27.0
golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
)
require golang.org/x/sys v0.27.0

2
go.sum
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@ -5,6 +5,8 @@ github.com/sagernet/sing v0.5.0/go.mod h1:ARkL0gM13/Iv5VCZmci/NuoOlePoIsW0m7BWfl
github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
golang.org/x/crypto v0.29.0 h1:L5SG1JTTXupVV3n6sUqMTeWbjAyfPwoda2DLX8J8FrQ=
golang.org/x/crypto v0.29.0/go.mod h1:+F4F4N5hv6v38hfeYwTdx20oUvLLc+QfrE9Ax9HtgRg=
golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 h1:2dVuKD2vS7b0QIHQbpyTISPd0LeHDbnYEryqj5Q1ug8=
golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56/go.mod h1:M4RDyNAINzryxdtnbRXRL/OHtkFuWGRjvuhBJpk2IlY=
golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

3
internal/README.md Normal file
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@ -0,0 +1,3 @@
# internal
copied from go 1.23.3

149
internal/byteorder/byteorder.go Normal file
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@ -0,0 +1,149 @@
// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package byteorder provides functions for decoding and encoding
// little and big endian integer types from/to byte slices.
package byteorder
func LeUint16(b []byte) uint16 {
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
return uint16(b[0]) | uint16(b[1])<<8
}
func LePutUint16(b []byte, v uint16) {
_ = b[1] // early bounds check to guarantee safety of writes below
b[0] = byte(v)
b[1] = byte(v >> 8)
}
func LeAppendUint16(b []byte, v uint16) []byte {
return append(b,
byte(v),
byte(v>>8),
)
}
func LeUint32(b []byte) uint32 {
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func LePutUint32(b []byte, v uint32) {
_ = b[3] // early bounds check to guarantee safety of writes below
b[0] = byte(v)
b[1] = byte(v >> 8)
b[2] = byte(v >> 16)
b[3] = byte(v >> 24)
}
func LeAppendUint32(b []byte, v uint32) []byte {
return append(b,
byte(v),
byte(v>>8),
byte(v>>16),
byte(v>>24),
)
}
func LeUint64(b []byte) uint64 {
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func LePutUint64(b []byte, v uint64) {
_ = b[7] // early bounds check to guarantee safety of writes below
b[0] = byte(v)
b[1] = byte(v >> 8)
b[2] = byte(v >> 16)
b[3] = byte(v >> 24)
b[4] = byte(v >> 32)
b[5] = byte(v >> 40)
b[6] = byte(v >> 48)
b[7] = byte(v >> 56)
}
func LeAppendUint64(b []byte, v uint64) []byte {
return append(b,
byte(v),
byte(v>>8),
byte(v>>16),
byte(v>>24),
byte(v>>32),
byte(v>>40),
byte(v>>48),
byte(v>>56),
)
}
func BeUint16(b []byte) uint16 {
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
return uint16(b[1]) | uint16(b[0])<<8
}
func BePutUint16(b []byte, v uint16) {
_ = b[1] // early bounds check to guarantee safety of writes below
b[0] = byte(v >> 8)
b[1] = byte(v)
}
func BeAppendUint16(b []byte, v uint16) []byte {
return append(b,
byte(v>>8),
byte(v),
)
}
func BeUint32(b []byte) uint32 {
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
}
func BePutUint32(b []byte, v uint32) {
_ = b[3] // early bounds check to guarantee safety of writes below
b[0] = byte(v >> 24)
b[1] = byte(v >> 16)
b[2] = byte(v >> 8)
b[3] = byte(v)
}
func BeAppendUint32(b []byte, v uint32) []byte {
return append(b,
byte(v>>24),
byte(v>>16),
byte(v>>8),
byte(v),
)
}
func BeUint64(b []byte) uint64 {
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
}
func BePutUint64(b []byte, v uint64) {
_ = b[7] // early bounds check to guarantee safety of writes below
b[0] = byte(v >> 56)
b[1] = byte(v >> 48)
b[2] = byte(v >> 40)
b[3] = byte(v >> 32)
b[4] = byte(v >> 24)
b[5] = byte(v >> 16)
b[6] = byte(v >> 8)
b[7] = byte(v)
}
func BeAppendUint64(b []byte, v uint64) []byte {
return append(b,
byte(v>>56),
byte(v>>48),
byte(v>>40),
byte(v>>32),
byte(v>>24),
byte(v>>16),
byte(v>>8),
byte(v),
)
}

258
internal/hpke/hpke.go Normal file
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@ -0,0 +1,258 @@
// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package hpke
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"crypto/ecdh"
"crypto/rand"
"encoding/binary"
"errors"
"math/bits"
"golang.org/x/crypto/chacha20poly1305"
"golang.org/x/crypto/hkdf"
)
// testingOnlyGenerateKey is only used during testing, to provide
// a fixed test key to use when checking the RFC 9180 vectors.
var testingOnlyGenerateKey func() (*ecdh.PrivateKey, error)
type hkdfKDF struct {
hash crypto.Hash
}
func (kdf *hkdfKDF) LabeledExtract(suiteID []byte, salt []byte, label string, inputKey []byte) []byte {
labeledIKM := make([]byte, 0, 7+len(suiteID)+len(label)+len(inputKey))
labeledIKM = append(labeledIKM, []byte("HPKE-v1")...)
labeledIKM = append(labeledIKM, suiteID...)
labeledIKM = append(labeledIKM, label...)
labeledIKM = append(labeledIKM, inputKey...)
return hkdf.Extract(kdf.hash.New, labeledIKM, salt)
}
func (kdf *hkdfKDF) LabeledExpand(suiteID []byte, randomKey []byte, label string, info []byte, length uint16) []byte {
labeledInfo := make([]byte, 0, 2+7+len(suiteID)+len(label)+len(info))
labeledInfo = binary.BigEndian.AppendUint16(labeledInfo, length)
labeledInfo = append(labeledInfo, []byte("HPKE-v1")...)
labeledInfo = append(labeledInfo, suiteID...)
labeledInfo = append(labeledInfo, label...)
labeledInfo = append(labeledInfo, info...)
out := make([]byte, length)
n, err := hkdf.Expand(kdf.hash.New, randomKey, labeledInfo).Read(out)
if err != nil || n != int(length) {
panic("hpke: LabeledExpand failed unexpectedly")
}
return out
}
// dhKEM implements the KEM specified in RFC 9180, Section 4.1.
type dhKEM struct {
dh ecdh.Curve
kdf hkdfKDF
suiteID []byte
nSecret uint16
}
var SupportedKEMs = map[uint16]struct {
curve ecdh.Curve
hash crypto.Hash
nSecret uint16
}{
// RFC 9180 Section 7.1
0x0020: {ecdh.X25519(), crypto.SHA256, 32},
}
func newDHKem(kemID uint16) (*dhKEM, error) {
suite, ok := SupportedKEMs[kemID]
if !ok {
return nil, errors.New("unsupported suite ID")
}
return &dhKEM{
dh: suite.curve,
kdf: hkdfKDF{suite.hash},
suiteID: binary.BigEndian.AppendUint16([]byte("KEM"), kemID),
nSecret: suite.nSecret,
}, nil
}
func (dh *dhKEM) ExtractAndExpand(dhKey, kemContext []byte) []byte {
eaePRK := dh.kdf.LabeledExtract(dh.suiteID[:], nil, "eae_prk", dhKey)
return dh.kdf.LabeledExpand(dh.suiteID[:], eaePRK, "shared_secret", kemContext, dh.nSecret)
}
func (dh *dhKEM) Encap(pubRecipient *ecdh.PublicKey) (sharedSecret []byte, encapPub []byte, err error) {
var privEph *ecdh.PrivateKey
if testingOnlyGenerateKey != nil {
privEph, err = testingOnlyGenerateKey()
} else {
privEph, err = dh.dh.GenerateKey(rand.Reader)
}
if err != nil {
return nil, nil, err
}
dhVal, err := privEph.ECDH(pubRecipient)
if err != nil {
return nil, nil, err
}
encPubEph := privEph.PublicKey().Bytes()
encPubRecip := pubRecipient.Bytes()
kemContext := append(encPubEph, encPubRecip...)
return dh.ExtractAndExpand(dhVal, kemContext), encPubEph, nil
}
type Sender struct {
aead cipher.AEAD
kem *dhKEM
sharedSecret []byte
suiteID []byte
key []byte
baseNonce []byte
exporterSecret []byte
seqNum uint128
}
var aesGCMNew = func(key []byte) (cipher.AEAD, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
return cipher.NewGCM(block)
}
var SupportedAEADs = map[uint16]struct {
keySize int
nonceSize int
aead func([]byte) (cipher.AEAD, error)
}{
// RFC 9180, Section 7.3
0x0001: {keySize: 16, nonceSize: 12, aead: aesGCMNew},
0x0002: {keySize: 32, nonceSize: 12, aead: aesGCMNew},
0x0003: {keySize: chacha20poly1305.KeySize, nonceSize: chacha20poly1305.NonceSize, aead: chacha20poly1305.New},
}
var SupportedKDFs = map[uint16]func() *hkdfKDF{
// RFC 9180, Section 7.2
0x0001: func() *hkdfKDF { return &hkdfKDF{crypto.SHA256} },
}
func SetupSender(kemID, kdfID, aeadID uint16, pub crypto.PublicKey, info []byte) ([]byte, *Sender, error) {
suiteID := SuiteID(kemID, kdfID, aeadID)
kem, err := newDHKem(kemID)
if err != nil {
return nil, nil, err
}
pubRecipient, ok := pub.(*ecdh.PublicKey)
if !ok {
return nil, nil, errors.New("incorrect public key type")
}
sharedSecret, encapsulatedKey, err := kem.Encap(pubRecipient)
if err != nil {
return nil, nil, err
}
kdfInit, ok := SupportedKDFs[kdfID]
if !ok {
return nil, nil, errors.New("unsupported KDF id")
}
kdf := kdfInit()
aeadInfo, ok := SupportedAEADs[aeadID]
if !ok {
return nil, nil, errors.New("unsupported AEAD id")
}
pskIDHash := kdf.LabeledExtract(suiteID, nil, "psk_id_hash", nil)
infoHash := kdf.LabeledExtract(suiteID, nil, "info_hash", info)
ksContext := append([]byte{0}, pskIDHash...)
ksContext = append(ksContext, infoHash...)
secret := kdf.LabeledExtract(suiteID, sharedSecret, "secret", nil)
key := kdf.LabeledExpand(suiteID, secret, "key", ksContext, uint16(aeadInfo.keySize) /* Nk - key size for AEAD */)
baseNonce := kdf.LabeledExpand(suiteID, secret, "base_nonce", ksContext, uint16(aeadInfo.nonceSize) /* Nn - nonce size for AEAD */)
exporterSecret := kdf.LabeledExpand(suiteID, secret, "exp", ksContext, uint16(kdf.hash.Size()) /* Nh - hash output size of the kdf*/)
aead, err := aeadInfo.aead(key)
if err != nil {
return nil, nil, err
}
return encapsulatedKey, &Sender{
kem: kem,
aead: aead,
sharedSecret: sharedSecret,
suiteID: suiteID,
key: key,
baseNonce: baseNonce,
exporterSecret: exporterSecret,
}, nil
}
func (s *Sender) nextNonce() []byte {
nonce := s.seqNum.bytes()[16-s.aead.NonceSize():]
for i := range s.baseNonce {
nonce[i] ^= s.baseNonce[i]
}
// Message limit is, according to the RFC, 2^95+1, which
// is somewhat confusing, but we do as we're told.
if s.seqNum.bitLen() >= (s.aead.NonceSize()*8)-1 {
panic("message limit reached")
}
s.seqNum = s.seqNum.addOne()
return nonce
}
func (s *Sender) Seal(aad, plaintext []byte) ([]byte, error) {
ciphertext := s.aead.Seal(nil, s.nextNonce(), plaintext, aad)
return ciphertext, nil
}
func SuiteID(kemID, kdfID, aeadID uint16) []byte {
suiteID := make([]byte, 0, 4+2+2+2)
suiteID = append(suiteID, []byte("HPKE")...)
suiteID = binary.BigEndian.AppendUint16(suiteID, kemID)
suiteID = binary.BigEndian.AppendUint16(suiteID, kdfID)
suiteID = binary.BigEndian.AppendUint16(suiteID, aeadID)
return suiteID
}
func ParseHPKEPublicKey(kemID uint16, bytes []byte) (*ecdh.PublicKey, error) {
kemInfo, ok := SupportedKEMs[kemID]
if !ok {
return nil, errors.New("unsupported KEM id")
}
return kemInfo.curve.NewPublicKey(bytes)
}
type uint128 struct {
hi, lo uint64
}
func (u uint128) addOne() uint128 {
lo, carry := bits.Add64(u.lo, 1, 0)
return uint128{u.hi + carry, lo}
}
func (u uint128) bitLen() int {
return bits.Len64(u.hi) + bits.Len64(u.lo)
}
func (u uint128) bytes() []byte {
b := make([]byte, 16)
binary.BigEndian.PutUint64(b[0:], u.hi)
binary.BigEndian.PutUint64(b[8:], u.lo)
return b
}

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internal/mlkem768/mlkem768.go Normal file
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// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package mlkem768 implements the quantum-resistant key encapsulation method
// ML-KEM (formerly known as Kyber).
//
// Only the recommended ML-KEM-768 parameter set is provided.
//
// The version currently implemented is the one specified by [NIST FIPS 203 ipd],
// with the unintentional transposition of the matrix A reverted to match the
// behavior of [Kyber version 3.0]. Future versions of this package might
// introduce backwards incompatible changes to implement changes to FIPS 203.
//
// [Kyber version 3.0]: https://pq-crystals.org/kyber/data/kyber-specification-round3-20210804.pdf
// [NIST FIPS 203 ipd]: https://doi.org/10.6028/NIST.FIPS.203.ipd
package mlkem768
// This package targets security, correctness, simplicity, readability, and
// reviewability as its primary goals. All critical operations are performed in
// constant time.
//
// Variable and function names, as well as code layout, are selected to
// facilitate reviewing the implementation against the NIST FIPS 203 ipd
// document.
//
// Reviewers unfamiliar with polynomials or linear algebra might find the
// background at https://words.filippo.io/kyber-math/ useful.
import (
"crypto/rand"
"crypto/subtle"
"errors"
"github.com/sagernet/sing-shadowtls/internal/byteorder"
"golang.org/x/crypto/sha3"
)
const (
// ML-KEM global constants.
n = 256
q = 3329
log2q = 12
// ML-KEM-768 parameters. The code makes assumptions based on these values,
// they can't be changed blindly.
k = 3
η = 2
du = 10
dv = 4
// encodingSizeX is the byte size of a ringElement or nttElement encoded
// by ByteEncode_X (FIPS 203 (DRAFT), Algorithm 4).
encodingSize12 = n * log2q / 8
encodingSize10 = n * du / 8
encodingSize4 = n * dv / 8
encodingSize1 = n * 1 / 8
messageSize = encodingSize1
decryptionKeySize = k * encodingSize12
encryptionKeySize = k*encodingSize12 + 32
CiphertextSize = k*encodingSize10 + encodingSize4
EncapsulationKeySize = encryptionKeySize
DecapsulationKeySize = decryptionKeySize + encryptionKeySize + 32 + 32
SharedKeySize = 32
SeedSize = 32 + 32
)
// A DecapsulationKey is the secret key used to decapsulate a shared key from a
// ciphertext. It includes various precomputed values.
type DecapsulationKey struct {
dk [DecapsulationKeySize]byte
encryptionKey
decryptionKey
}
// Bytes returns the extended encoding of the decapsulation key, according to
// FIPS 203 (DRAFT).
func (dk *DecapsulationKey) Bytes() []byte {
var b [DecapsulationKeySize]byte
copy(b[:], dk.dk[:])
return b[:]
}
// EncapsulationKey returns the public encapsulation key necessary to produce
// ciphertexts.
func (dk *DecapsulationKey) EncapsulationKey() []byte {
var b [EncapsulationKeySize]byte
copy(b[:], dk.dk[decryptionKeySize:])
return b[:]
}
// encryptionKey is the parsed and expanded form of a PKE encryption key.
type encryptionKey struct {
t [k]nttElement // ByteDecode₁₂(ek[:384k])
A [k * k]nttElement // A[i*k+j] = sampleNTT(ρ, j, i)
}
// decryptionKey is the parsed and expanded form of a PKE decryption key.
type decryptionKey struct {
s [k]nttElement // ByteDecode₁₂(dk[:decryptionKeySize])
}
// GenerateKey generates a new decapsulation key, drawing random bytes from
// crypto/rand. The decapsulation key must be kept secret.
func GenerateKey() (*DecapsulationKey, error) {
// The actual logic is in a separate function to outline this allocation.
dk := &DecapsulationKey{}
return generateKey(dk)
}
func generateKey(dk *DecapsulationKey) (*DecapsulationKey, error) {
var d [32]byte
if _, err := rand.Read(d[:]); err != nil {
return nil, errors.New("mlkem768: crypto/rand Read failed: " + err.Error())
}
var z [32]byte
if _, err := rand.Read(z[:]); err != nil {
return nil, errors.New("mlkem768: crypto/rand Read failed: " + err.Error())
}
return kemKeyGen(dk, &d, &z), nil
}
// NewKeyFromSeed deterministically generates a decapsulation key from a 64-byte
// seed in the "d || z" form. The seed must be uniformly random.
func NewKeyFromSeed(seed []byte) (*DecapsulationKey, error) {
// The actual logic is in a separate function to outline this allocation.
dk := &DecapsulationKey{}
return newKeyFromSeed(dk, seed)
}
func newKeyFromSeed(dk *DecapsulationKey, seed []byte) (*DecapsulationKey, error) {
if len(seed) != SeedSize {
return nil, errors.New("mlkem768: invalid seed length")
}
d := (*[32]byte)(seed[:32])
z := (*[32]byte)(seed[32:])
return kemKeyGen(dk, d, z), nil
}
// NewKeyFromExtendedEncoding parses a decapsulation key from its FIPS 203
// (DRAFT) extended encoding.
func NewKeyFromExtendedEncoding(decapsulationKey []byte) (*DecapsulationKey, error) {
// The actual logic is in a separate function to outline this allocation.
dk := &DecapsulationKey{}
return newKeyFromExtendedEncoding(dk, decapsulationKey)
}
func newKeyFromExtendedEncoding(dk *DecapsulationKey, dkBytes []byte) (*DecapsulationKey, error) {
if len(dkBytes) != DecapsulationKeySize {
return nil, errors.New("mlkem768: invalid decapsulation key length")
}
// Note that we don't check that H(ek) matches ekPKE, as that's not
// specified in FIPS 203 (DRAFT). This is one reason to prefer the seed
// private key format.
dk.dk = [DecapsulationKeySize]byte(dkBytes)
dkPKE := dkBytes[:decryptionKeySize]
if err := parseDK(&dk.decryptionKey, dkPKE); err != nil {
return nil, err
}
ekPKE := dkBytes[decryptionKeySize : decryptionKeySize+encryptionKeySize]
if err := parseEK(&dk.encryptionKey, ekPKE); err != nil {
return nil, err
}
return dk, nil
}
// kemKeyGen generates a decapsulation key.
//
// It implements ML-KEM.KeyGen according to FIPS 203 (DRAFT), Algorithm 15, and
// K-PKE.KeyGen according to FIPS 203 (DRAFT), Algorithm 12. The two are merged
// to save copies and allocations.
func kemKeyGen(dk *DecapsulationKey, d, z *[32]byte) *DecapsulationKey {
if dk == nil {
dk = &DecapsulationKey{}
}
G := sha3.Sum512(d[:])
ρ, σ := G[:32], G[32:]
A := &dk.A
for i := byte(0); i < k; i++ {
for j := byte(0); j < k; j++ {
// Note that this is consistent with Kyber round 3, rather than with
// the initial draft of FIPS 203, because NIST signaled that the
// change was involuntary and will be reverted.
A[i*k+j] = sampleNTT(ρ, j, i)
}
}
var N byte
s := &dk.s
for i := range s {
s[i] = ntt(samplePolyCBD(σ, N))
N++
}
e := make([]nttElement, k)
for i := range e {
e[i] = ntt(samplePolyCBD(σ, N))
N++
}
t := &dk.t
for i := range t { // t = A ◦ s + e
t[i] = e[i]
for j := range s {
t[i] = polyAdd(t[i], nttMul(A[i*k+j], s[j]))
}
}
// dkPKE ← ByteEncode₁₂(s)
// ekPKE ← ByteEncode₁₂(t) || ρ
// ek ← ekPKE
// dk ← dkPKE || ek || H(ek) || z
dkB := dk.dk[:0]
for i := range s {
dkB = polyByteEncode(dkB, s[i])
}
for i := range t {
dkB = polyByteEncode(dkB, t[i])
}
dkB = append(dkB, ρ...)
H := sha3.New256()
H.Write(dkB[decryptionKeySize:])
dkB = H.Sum(dkB)
dkB = append(dkB, z[:]...)
if len(dkB) != len(dk.dk) {
panic("mlkem768: internal error: invalid decapsulation key size")
}
return dk
}
// Encapsulate generates a shared key and an associated ciphertext from an
// encapsulation key, drawing random bytes from crypto/rand.
// If the encapsulation key is not valid, Encapsulate returns an error.
//
// The shared key must be kept secret.
func Encapsulate(encapsulationKey []byte) (ciphertext, sharedKey []byte, err error) {
// The actual logic is in a separate function to outline this allocation.
var cc [CiphertextSize]byte
return encapsulate(&cc, encapsulationKey)
}
func encapsulate(cc *[CiphertextSize]byte, encapsulationKey []byte) (ciphertext, sharedKey []byte, err error) {
if len(encapsulationKey) != EncapsulationKeySize {
return nil, nil, errors.New("mlkem768: invalid encapsulation key length")
}
var m [messageSize]byte
if _, err := rand.Read(m[:]); err != nil {
return nil, nil, errors.New("mlkem768: crypto/rand Read failed: " + err.Error())
}
return kemEncaps(cc, encapsulationKey, &m)
}
// kemEncaps generates a shared key and an associated ciphertext.
//
// It implements ML-KEM.Encaps according to FIPS 203 (DRAFT), Algorithm 16.
func kemEncaps(cc *[CiphertextSize]byte, ek []byte, m *[messageSize]byte) (c, K []byte, err error) {
if cc == nil {
cc = &[CiphertextSize]byte{}
}
H := sha3.Sum256(ek[:])
g := sha3.New512()
g.Write(m[:])
g.Write(H[:])
G := g.Sum(nil)
K, r := G[:SharedKeySize], G[SharedKeySize:]
var ex encryptionKey
if err := parseEK(&ex, ek[:]); err != nil {
return nil, nil, err
}
c = pkeEncrypt(cc, &ex, m, r)
return c, K, nil
}
// parseEK parses an encryption key from its encoded form.
//
// It implements the initial stages of K-PKE.Encrypt according to FIPS 203
// (DRAFT), Algorithm 13.
func parseEK(ex *encryptionKey, ekPKE []byte) error {
if len(ekPKE) != encryptionKeySize {
return errors.New("mlkem768: invalid encryption key length")
}
for i := range ex.t {
var err error
ex.t[i], err = polyByteDecode[nttElement](ekPKE[:encodingSize12])
if err != nil {
return err
}
ekPKE = ekPKE[encodingSize12:]
}
ρ := ekPKE
for i := byte(0); i < k; i++ {
for j := byte(0); j < k; j++ {
// See the note in pkeKeyGen about the order of the indices being
// consistent with Kyber round 3.
ex.A[i*k+j] = sampleNTT(ρ, j, i)
}
}
return nil
}
// pkeEncrypt encrypt a plaintext message.
//
// It implements K-PKE.Encrypt according to FIPS 203 (DRAFT), Algorithm 13,
// although the computation of t and AT is done in parseEK.
func pkeEncrypt(cc *[CiphertextSize]byte, ex *encryptionKey, m *[messageSize]byte, rnd []byte) []byte {
var N byte
r, e1 := make([]nttElement, k), make([]ringElement, k)
for i := range r {
r[i] = ntt(samplePolyCBD(rnd, N))
N++
}
for i := range e1 {
e1[i] = samplePolyCBD(rnd, N)
N++
}
e2 := samplePolyCBD(rnd, N)
u := make([]ringElement, k) // NTT⁻¹(AT ◦ r) + e1
for i := range u {
u[i] = e1[i]
for j := range r {
// Note that i and j are inverted, as we need the transposed of A.
u[i] = polyAdd(u[i], inverseNTT(nttMul(ex.A[j*k+i], r[j])))
}
}
μ := ringDecodeAndDecompress1(m)
var vNTT nttElement // t⊺ ◦ r
for i := range ex.t {
vNTT = polyAdd(vNTT, nttMul(ex.t[i], r[i]))
}
v := polyAdd(polyAdd(inverseNTT(vNTT), e2), μ)
c := cc[:0]
for _, f := range u {
c = ringCompressAndEncode10(c, f)
}
c = ringCompressAndEncode4(c, v)
return c
}
// Decapsulate generates a shared key from a ciphertext and a decapsulation key.
// If the ciphertext is not valid, Decapsulate returns an error.
//
// The shared key must be kept secret.
func Decapsulate(dk *DecapsulationKey, ciphertext []byte) (sharedKey []byte, err error) {
if len(ciphertext) != CiphertextSize {
return nil, errors.New("mlkem768: invalid ciphertext length")
}
c := (*[CiphertextSize]byte)(ciphertext)
return kemDecaps(dk, c), nil
}
// kemDecaps produces a shared key from a ciphertext.
//
// It implements ML-KEM.Decaps according to FIPS 203 (DRAFT), Algorithm 17.
func kemDecaps(dk *DecapsulationKey, c *[CiphertextSize]byte) (K []byte) {
h := dk.dk[decryptionKeySize+encryptionKeySize : decryptionKeySize+encryptionKeySize+32]
z := dk.dk[decryptionKeySize+encryptionKeySize+32:]
m := pkeDecrypt(&dk.decryptionKey, c)
g := sha3.New512()
g.Write(m[:])
g.Write(h)
G := g.Sum(nil)
Kprime, r := G[:SharedKeySize], G[SharedKeySize:]
J := sha3.NewShake256()
J.Write(z)
J.Write(c[:])
Kout := make([]byte, SharedKeySize)
J.Read(Kout)
var cc [CiphertextSize]byte
c1 := pkeEncrypt(&cc, &dk.encryptionKey, (*[32]byte)(m), r)
subtle.ConstantTimeCopy(subtle.ConstantTimeCompare(c[:], c1), Kout, Kprime)
return Kout
}
// parseDK parses a decryption key from its encoded form.
//
// It implements the computation of s from K-PKE.Decrypt according to FIPS 203
// (DRAFT), Algorithm 14.
func parseDK(dx *decryptionKey, dkPKE []byte) error {
if len(dkPKE) != decryptionKeySize {
return errors.New("mlkem768: invalid decryption key length")
}
for i := range dx.s {
f, err := polyByteDecode[nttElement](dkPKE[:encodingSize12])
if err != nil {
return err
}
dx.s[i] = f
dkPKE = dkPKE[encodingSize12:]
}
return nil
}
// pkeDecrypt decrypts a ciphertext.
//
// It implements K-PKE.Decrypt according to FIPS 203 (DRAFT), Algorithm 14,
// although the computation of s is done in parseDK.
func pkeDecrypt(dx *decryptionKey, c *[CiphertextSize]byte) []byte {
u := make([]ringElement, k)
for i := range u {
b := (*[encodingSize10]byte)(c[encodingSize10*i : encodingSize10*(i+1)])
u[i] = ringDecodeAndDecompress10(b)
}
b := (*[encodingSize4]byte)(c[encodingSize10*k:])
v := ringDecodeAndDecompress4(b)
var mask nttElement // s⊺ ◦ NTT(u)
for i := range dx.s {
mask = polyAdd(mask, nttMul(dx.s[i], ntt(u[i])))
}
w := polySub(v, inverseNTT(mask))
return ringCompressAndEncode1(nil, w)
}
// fieldElement is an integer modulo q, an element of ℤ_q. It is always reduced.
type fieldElement uint16
// fieldCheckReduced checks that a value a is < q.
func fieldCheckReduced(a uint16) (fieldElement, error) {
if a >= q {
return 0, errors.New("unreduced field element")
}
return fieldElement(a), nil
}
// fieldReduceOnce reduces a value a < 2q.
func fieldReduceOnce(a uint16) fieldElement {
x := a - q
// If x underflowed, then x >= 2¹⁶ - q > 2¹⁵, so the top bit is set.
x += (x >> 15) * q
return fieldElement(x)
}
func fieldAdd(a, b fieldElement) fieldElement {
x := uint16(a + b)
return fieldReduceOnce(x)
}
func fieldSub(a, b fieldElement) fieldElement {
x := uint16(a - b + q)
return fieldReduceOnce(x)
}
const (
barrettMultiplier = 5039 // 2¹² * 2¹² / q
barrettShift = 24 // log₂(2¹² * 2¹²)
)
// fieldReduce reduces a value a < 2q² using Barrett reduction, to avoid
// potentially variable-time division.
func fieldReduce(a uint32) fieldElement {
quotient := uint32((uint64(a) * barrettMultiplier) >> barrettShift)
return fieldReduceOnce(uint16(a - quotient*q))
}
func fieldMul(a, b fieldElement) fieldElement {
x := uint32(a) * uint32(b)
return fieldReduce(x)
}
// fieldMulSub returns a * (b - c). This operation is fused to save a
// fieldReduceOnce after the subtraction.
func fieldMulSub(a, b, c fieldElement) fieldElement {
x := uint32(a) * uint32(b-c+q)
return fieldReduce(x)
}
// fieldAddMul returns a * b + c * d. This operation is fused to save a
// fieldReduceOnce and a fieldReduce.
func fieldAddMul(a, b, c, d fieldElement) fieldElement {
x := uint32(a) * uint32(b)
x += uint32(c) * uint32(d)
return fieldReduce(x)
}
// compress maps a field element uniformly to the range 0 to 2ᵈ-1, according to
// FIPS 203 (DRAFT), Definition 4.5.
func compress(x fieldElement, d uint8) uint16 {
// We want to compute (x * 2ᵈ) / q, rounded to nearest integer, with 1/2
// rounding up (see FIPS 203 (DRAFT), Section 2.3).
// Barrett reduction produces a quotient and a remainder in the range [0, 2q),
// such that dividend = quotient * q + remainder.
dividend := uint32(x) << d // x * 2ᵈ
quotient := uint32(uint64(dividend) * barrettMultiplier >> barrettShift)
remainder := dividend - quotient*q
// Since the remainder is in the range [0, 2q), not [0, q), we need to
// portion it into three spans for rounding.
//
// [ 0, q/2 ) -> round to 0
// [ q/2, q + q/2 ) -> round to 1
// [ q + q/2, 2q ) -> round to 2
//
// We can convert that to the following logic: add 1 if remainder > q/2,
// then add 1 again if remainder > q + q/2.
//
// Note that if remainder > x, then ⌊x⌋ - remainder underflows, and the top
// bit of the difference will be set.
quotient += (q/2 - remainder) >> 31 & 1
quotient += (q + q/2 - remainder) >> 31 & 1
// quotient might have overflowed at this point, so reduce it by masking.
var mask uint32 = (1 << d) - 1
return uint16(quotient & mask)
}
// decompress maps a number x between 0 and 2ᵈ-1 uniformly to the full range of
// field elements, according to FIPS 203 (DRAFT), Definition 4.6.
func decompress(y uint16, d uint8) fieldElement {
// We want to compute (y * q) / 2ᵈ, rounded to nearest integer, with 1/2
// rounding up (see FIPS 203 (DRAFT), Section 2.3).
dividend := uint32(y) * q
quotient := dividend >> d // (y * q) / 2ᵈ
// The d'th least-significant bit of the dividend (the most significant bit
// of the remainder) is 1 for the top half of the values that divide to the
// same quotient, which are the ones that round up.
quotient += dividend >> (d - 1) & 1
// quotient is at most (2¹¹-1) * q / 2¹¹ + 1 = 3328, so it didn't overflow.
return fieldElement(quotient)
}
// ringElement is a polynomial, an element of R_q, represented as an array
// according to FIPS 203 (DRAFT), Section 2.4.
type ringElement [n]fieldElement
// polyAdd adds two ringElements or nttElements.
func polyAdd[T ~[n]fieldElement](a, b T) (s T) {
for i := range s {
s[i] = fieldAdd(a[i], b[i])
}
return s
}
// polySub subtracts two ringElements or nttElements.
func polySub[T ~[n]fieldElement](a, b T) (s T) {
for i := range s {
s[i] = fieldSub(a[i], b[i])
}
return s
}
// polyByteEncode appends the 384-byte encoding of f to b.
//
// It implements ByteEncode₁₂, according to FIPS 203 (DRAFT), Algorithm 4.
func polyByteEncode[T ~[n]fieldElement](b []byte, f T) []byte {
out, B := sliceForAppend(b, encodingSize12)
for i := 0; i < n; i += 2 {
x := uint32(f[i]) | uint32(f[i+1])<<12
B[0] = uint8(x)
B[1] = uint8(x >> 8)
B[2] = uint8(x >> 16)
B = B[3:]
}
return out
}
// polyByteDecode decodes the 384-byte encoding of a polynomial, checking that
// all the coefficients are properly reduced. This achieves the "Modulus check"
// step of ML-KEM Encapsulation Input Validation.
//
// polyByteDecode is also used in ML-KEM Decapsulation, where the input
// validation is not required, but implicitly allowed by the specification.
//
// It implements ByteDecode₁₂, according to FIPS 203 (DRAFT), Algorithm 5.
func polyByteDecode[T ~[n]fieldElement](b []byte) (T, error) {
if len(b) != encodingSize12 {
return T{}, errors.New("mlkem768: invalid encoding length")
}
var f T
for i := 0; i < n; i += 2 {
d := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16
const mask12 = 0b1111_1111_1111
var err error
if f[i], err = fieldCheckReduced(uint16(d & mask12)); err != nil {
return T{}, errors.New("mlkem768: invalid polynomial encoding")
}
if f[i+1], err = fieldCheckReduced(uint16(d >> 12)); err != nil {
return T{}, errors.New("mlkem768: invalid polynomial encoding")
}
b = b[3:]
}
return f, nil
}
// sliceForAppend takes a slice and a requested number of bytes. It returns a
// slice with the contents of the given slice followed by that many bytes and a
// second slice that aliases into it and contains only the extra bytes. If the
// original slice has sufficient capacity then no allocation is performed.
func sliceForAppend(in []byte, n int) (head, tail []byte) {
if total := len(in) + n; cap(in) >= total {
head = in[:total]
} else {
head = make([]byte, total)
copy(head, in)
}
tail = head[len(in):]
return
}
// ringCompressAndEncode1 appends a 32-byte encoding of a ring element to s,
// compressing one coefficients per bit.
//
// It implements Compress₁, according to FIPS 203 (DRAFT), Definition 4.5,
// followed by ByteEncode₁, according to FIPS 203 (DRAFT), Algorithm 4.
func ringCompressAndEncode1(s []byte, f ringElement) []byte {
s, b := sliceForAppend(s, encodingSize1)
for i := range b {
b[i] = 0
}
for i := range f {
b[i/8] |= uint8(compress(f[i], 1) << (i % 8))
}
return s
}
// ringDecodeAndDecompress1 decodes a 32-byte slice to a ring element where each
// bit is mapped to 0 or ⌈q/2⌋.
//
// It implements ByteDecode₁, according to FIPS 203 (DRAFT), Algorithm 5,
// followed by Decompress₁, according to FIPS 203 (DRAFT), Definition 4.6.
func ringDecodeAndDecompress1(b *[encodingSize1]byte) ringElement {
var f ringElement
for i := range f {
b_i := b[i/8] >> (i % 8) & 1
const halfQ = (q + 1) / 2 // ⌈q/2⌋, rounded up per FIPS 203 (DRAFT), Section 2.3
f[i] = fieldElement(b_i) * halfQ // 0 decompresses to 0, and 1 to ⌈q/2⌋
}
return f
}
// ringCompressAndEncode4 appends a 128-byte encoding of a ring element to s,
// compressing two coefficients per byte.
//
// It implements Compress₄, according to FIPS 203 (DRAFT), Definition 4.5,
// followed by ByteEncode₄, according to FIPS 203 (DRAFT), Algorithm 4.
func ringCompressAndEncode4(s []byte, f ringElement) []byte {
s, b := sliceForAppend(s, encodingSize4)
for i := 0; i < n; i += 2 {
b[i/2] = uint8(compress(f[i], 4) | compress(f[i+1], 4)<<4)
}
return s
}
// ringDecodeAndDecompress4 decodes a 128-byte encoding of a ring element where
// each four bits are mapped to an equidistant distribution.
//
// It implements ByteDecode₄, according to FIPS 203 (DRAFT), Algorithm 5,
// followed by Decompress₄, according to FIPS 203 (DRAFT), Definition 4.6.
func ringDecodeAndDecompress4(b *[encodingSize4]byte) ringElement {
var f ringElement
for i := 0; i < n; i += 2 {
f[i] = fieldElement(decompress(uint16(b[i/2]&0b1111), 4))
f[i+1] = fieldElement(decompress(uint16(b[i/2]>>4), 4))
}
return f
}
// ringCompressAndEncode10 appends a 320-byte encoding of a ring element to s,
// compressing four coefficients per five bytes.
//
// It implements Compress₁₀, according to FIPS 203 (DRAFT), Definition 4.5,
// followed by ByteEncode₁₀, according to FIPS 203 (DRAFT), Algorithm 4.
func ringCompressAndEncode10(s []byte, f ringElement) []byte {
s, b := sliceForAppend(s, encodingSize10)
for i := 0; i < n; i += 4 {
var x uint64
x |= uint64(compress(f[i+0], 10))
x |= uint64(compress(f[i+1], 10)) << 10
x |= uint64(compress(f[i+2], 10)) << 20
x |= uint64(compress(f[i+3], 10)) << 30
b[0] = uint8(x)
b[1] = uint8(x >> 8)
b[2] = uint8(x >> 16)
b[3] = uint8(x >> 24)
b[4] = uint8(x >> 32)
b = b[5:]
}
return s
}
// ringDecodeAndDecompress10 decodes a 320-byte encoding of a ring element where
// each ten bits are mapped to an equidistant distribution.
//
// It implements ByteDecode₁₀, according to FIPS 203 (DRAFT), Algorithm 5,
// followed by Decompress₁₀, according to FIPS 203 (DRAFT), Definition 4.6.
func ringDecodeAndDecompress10(bb *[encodingSize10]byte) ringElement {
b := bb[:]
var f ringElement
for i := 0; i < n; i += 4 {
x := uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32
b = b[5:]
f[i] = fieldElement(decompress(uint16(x>>0&0b11_1111_1111), 10))
f[i+1] = fieldElement(decompress(uint16(x>>10&0b11_1111_1111), 10))
f[i+2] = fieldElement(decompress(uint16(x>>20&0b11_1111_1111), 10))
f[i+3] = fieldElement(decompress(uint16(x>>30&0b11_1111_1111), 10))
}
return f
}
// samplePolyCBD draws a ringElement from the special Dη distribution given a
// stream of random bytes generated by the PRF function, according to FIPS 203
// (DRAFT), Algorithm 7 and Definition 4.1.
func samplePolyCBD(s []byte, b byte) ringElement {
prf := sha3.NewShake256()
prf.Write(s)
prf.Write([]byte{b})
B := make([]byte, 128)
prf.Read(B)
// SamplePolyCBD simply draws four (2η) bits for each coefficient, and adds
// the first two and subtracts the last two.
var f ringElement
for i := 0; i < n; i += 2 {
b := B[i/2]
b_7, b_6, b_5, b_4 := b>>7, b>>6&1, b>>5&1, b>>4&1
b_3, b_2, b_1, b_0 := b>>3&1, b>>2&1, b>>1&1, b&1
f[i] = fieldSub(fieldElement(b_0+b_1), fieldElement(b_2+b_3))
f[i+1] = fieldSub(fieldElement(b_4+b_5), fieldElement(b_6+b_7))
}
return f
}
// nttElement is an NTT representation, an element of T_q, represented as an
// array according to FIPS 203 (DRAFT), Section 2.4.
type nttElement [n]fieldElement
// gammas are the values ζ^2BitRev7(i)+1 mod q for each index i.
var gammas = [128]fieldElement{17, 3312, 2761, 568, 583, 2746, 2649, 680, 1637, 1692, 723, 2606, 2288, 1041, 1100, 2229, 1409, 1920, 2662, 667, 3281, 48, 233, 3096, 756, 2573, 2156, 1173, 3015, 314, 3050, 279, 1703, 1626, 1651, 1678, 2789, 540, 1789, 1540, 1847, 1482, 952, 2377, 1461, 1868, 2687, 642, 939, 2390, 2308, 1021, 2437, 892, 2388, 941, 733, 2596, 2337, 992, 268, 3061, 641, 2688, 1584, 1745, 2298, 1031, 2037, 1292, 3220, 109, 375, 2954, 2549, 780, 2090, 1239, 1645, 1684, 1063, 2266, 319, 3010, 2773, 556, 757, 2572, 2099, 1230, 561, 2768, 2466, 863, 2594, 735, 2804, 525, 1092, 2237, 403, 2926, 1026, 2303, 1143, 2186, 2150, 1179, 2775, 554, 886, 2443, 1722, 1607, 1212, 2117, 1874, 1455, 1029, 2300, 2110, 1219, 2935, 394, 885, 2444, 2154, 1175}
// nttMul multiplies two nttElements.
//
// It implements MultiplyNTTs, according to FIPS 203 (DRAFT), Algorithm 10.
func nttMul(f, g nttElement) nttElement {
var h nttElement
// We use i += 2 for bounds check elimination. See https://go.dev/issue/66826.
for i := 0; i < 256; i += 2 {
a0, a1 := f[i], f[i+1]
b0, b1 := g[i], g[i+1]
h[i] = fieldAddMul(a0, b0, fieldMul(a1, b1), gammas[i/2])
h[i+1] = fieldAddMul(a0, b1, a1, b0)
}
return h
}
// zetas are the values ζ^BitRev7(k) mod q for each index k.
var zetas = [128]fieldElement{1, 1729, 2580, 3289, 2642, 630, 1897, 848, 1062, 1919, 193, 797, 2786, 3260, 569, 1746, 296, 2447, 1339, 1476, 3046, 56, 2240, 1333, 1426, 2094, 535, 2882, 2393, 2879, 1974, 821, 289, 331, 3253, 1756, 1197, 2304, 2277, 2055, 650, 1977, 2513, 632, 2865, 33, 1320, 1915, 2319, 1435, 807, 452, 1438, 2868, 1534, 2402, 2647, 2617, 1481, 648, 2474, 3110, 1227, 910, 17, 2761, 583, 2649, 1637, 723, 2288, 1100, 1409, 2662, 3281, 233, 756, 2156, 3015, 3050, 1703, 1651, 2789, 1789, 1847, 952, 1461, 2687, 939, 2308, 2437, 2388, 733, 2337, 268, 641, 1584, 2298, 2037, 3220, 375, 2549, 2090, 1645, 1063, 319, 2773, 757, 2099, 561, 2466, 2594, 2804, 1092, 403, 1026, 1143, 2150, 2775, 886, 1722, 1212, 1874, 1029, 2110, 2935, 885, 2154}
// ntt maps a ringElement to its nttElement representation.
//
// It implements NTT, according to FIPS 203 (DRAFT), Algorithm 8.
func ntt(f ringElement) nttElement {
k := 1
for len := 128; len >= 2; len /= 2 {
for start := 0; start < 256; start += 2 * len {
zeta := zetas[k]
k++
// Bounds check elimination hint.
f, flen := f[start:start+len], f[start+len:start+len+len]
for j := 0; j < len; j++ {
t := fieldMul(zeta, flen[j])
flen[j] = fieldSub(f[j], t)
f[j] = fieldAdd(f[j], t)
}
}
}
return nttElement(f)
}
// inverseNTT maps a nttElement back to the ringElement it represents.
//
// It implements NTT⁻¹, according to FIPS 203 (DRAFT), Algorithm 9.
func inverseNTT(f nttElement) ringElement {
k := 127
for len := 2; len <= 128; len *= 2 {
for start := 0; start < 256; start += 2 * len {
zeta := zetas[k]
k--
// Bounds check elimination hint.
f, flen := f[start:start+len], f[start+len:start+len+len]
for j := 0; j < len; j++ {
t := f[j]
f[j] = fieldAdd(t, flen[j])
flen[j] = fieldMulSub(zeta, flen[j], t)
}
}
}
for i := range f {
f[i] = fieldMul(f[i], 3303) // 3303 = 128⁻¹ mod q
}
return ringElement(f)
}
// sampleNTT draws a uniformly random nttElement from a stream of uniformly
// random bytes generated by the XOF function, according to FIPS 203 (DRAFT),
// Algorithm 6 and Definition 4.2.
func sampleNTT(rho []byte, ii, jj byte) nttElement {
B := sha3.NewShake128()
B.Write(rho)
B.Write([]byte{ii, jj})
// SampleNTT essentially draws 12 bits at a time from r, interprets them in
// little-endian, and rejects values higher than q, until it drew 256
// values. (The rejection rate is approximately 19%.)
//
// To do this from a bytes stream, it draws three bytes at a time, and
// splits them into two uint16 appropriately masked.
//
// r₀ r₁ r₂
// |- - - - - - - -|- - - - - - - -|- - - - - - - -|
//
// Uint16(r₀ || r₁)
// |- - - - - - - - - - - - - - - -|
// |- - - - - - - - - - - -|
// d₁
//
// Uint16(r₁ || r₂)
// |- - - - - - - - - - - - - - - -|
// |- - - - - - - - - - - -|
// d₂
//
// Note that in little-endian, the rightmost bits are the most significant
// bits (dropped with a mask) and the leftmost bits are the least
// significant bits (dropped with a right shift).
var a nttElement
var j int // index into a
var buf [24]byte // buffered reads from B
off := len(buf) // index into buf, starts in a "buffer fully consumed" state
for {
if off >= len(buf) {
B.Read(buf[:])
off = 0
}
d1 := byteorder.LeUint16(buf[off:]) & 0b1111_1111_1111
d2 := byteorder.LeUint16(buf[off+1:]) >> 4
off += 3
if d1 < q {
a[j] = fieldElement(d1)
j++
}
if j >= len(a) {
break
}
if d2 < q {
a[j] = fieldElement(d2)
j++
}
if j >= len(a) {
break
}
}
return a
}

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import "strconv"
// An AlertError is a TLS alert.
//
// When using a QUIC transport, QUICConn methods will return an error
// which wraps AlertError rather than sending a TLS alert.
type AlertError uint8
func (e AlertError) Error() string {
return alert(e).String()
}
type alert uint8
const (
// alert level
alertLevelWarning = 1
alertLevelError = 2
)
const (
alertCloseNotify alert = 0
alertUnexpectedMessage alert = 10
alertBadRecordMAC alert = 20
alertDecryptionFailed alert = 21
alertRecordOverflow alert = 22
alertDecompressionFailure alert = 30
alertHandshakeFailure alert = 40
alertBadCertificate alert = 42
alertUnsupportedCertificate alert = 43
alertCertificateRevoked alert = 44
alertCertificateExpired alert = 45
alertCertificateUnknown alert = 46
alertIllegalParameter alert = 47
alertUnknownCA alert = 48
alertAccessDenied alert = 49
alertDecodeError alert = 50
alertDecryptError alert = 51
alertExportRestriction alert = 60
alertProtocolVersion alert = 70
alertInsufficientSecurity alert = 71
alertInternalError alert = 80
alertInappropriateFallback alert = 86
alertUserCanceled alert = 90
alertNoRenegotiation alert = 100
alertMissingExtension alert = 109
alertUnsupportedExtension alert = 110
alertCertificateUnobtainable alert = 111
alertUnrecognizedName alert = 112
alertBadCertificateStatusResponse alert = 113
alertBadCertificateHashValue alert = 114
alertUnknownPSKIdentity alert = 115
alertCertificateRequired alert = 116
alertNoApplicationProtocol alert = 120
alertECHRequired alert = 121
)
var alertText = map[alert]string{
alertCloseNotify: "close notify",
alertUnexpectedMessage: "unexpected message",
alertBadRecordMAC: "bad record MAC",
alertDecryptionFailed: "decryption failed",
alertRecordOverflow: "record overflow",
alertDecompressionFailure: "decompression failure",
alertHandshakeFailure: "handshake failure",
alertBadCertificate: "bad certificate",
alertUnsupportedCertificate: "unsupported certificate",
alertCertificateRevoked: "revoked certificate",
alertCertificateExpired: "expired certificate",
alertCertificateUnknown: "unknown certificate",
alertIllegalParameter: "illegal parameter",
alertUnknownCA: "unknown certificate authority",
alertAccessDenied: "access denied",
alertDecodeError: "error decoding message",
alertDecryptError: "error decrypting message",
alertExportRestriction: "export restriction",
alertProtocolVersion: "protocol version not supported",
alertInsufficientSecurity: "insufficient security level",
alertInternalError: "internal error",
alertInappropriateFallback: "inappropriate fallback",
alertUserCanceled: "user canceled",
alertNoRenegotiation: "no renegotiation",
alertMissingExtension: "missing extension",
alertUnsupportedExtension: "unsupported extension",
alertCertificateUnobtainable: "certificate unobtainable",
alertUnrecognizedName: "unrecognized name",
alertBadCertificateStatusResponse: "bad certificate status response",
alertBadCertificateHashValue: "bad certificate hash value",
alertUnknownPSKIdentity: "unknown PSK identity",
alertCertificateRequired: "certificate required",
alertNoApplicationProtocol: "no application protocol",
alertECHRequired: "encrypted client hello required",
}
func (e alert) String() string {
s, ok := alertText[e]
if ok {
return "tls: " + s
}
return "tls: alert(" + strconv.Itoa(int(e)) + ")"
}
func (e alert) Error() string {
return e.String()
}

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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"bytes"
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rsa"
"errors"
"fmt"
"hash"
"io"
)
// verifyHandshakeSignature verifies a signature against pre-hashed
// (if required) handshake contents.
func verifyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, signed, sig []byte) error {
switch sigType {
case signatureECDSA:
pubKey, ok := pubkey.(*ecdsa.PublicKey)
if !ok {
return fmt.Errorf("expected an ECDSA public key, got %T", pubkey)
}
if !ecdsa.VerifyASN1(pubKey, signed, sig) {
return errors.New("ECDSA verification failure")
}
case signatureEd25519:
pubKey, ok := pubkey.(ed25519.PublicKey)
if !ok {
return fmt.Errorf("expected an Ed25519 public key, got %T", pubkey)
}
if !ed25519.Verify(pubKey, signed, sig) {
return errors.New("Ed25519 verification failure")
}
case signaturePKCS1v15:
pubKey, ok := pubkey.(*rsa.PublicKey)
if !ok {
return fmt.Errorf("expected an RSA public key, got %T", pubkey)
}
if err := rsa.VerifyPKCS1v15(pubKey, hashFunc, signed, sig); err != nil {
return err
}
case signatureRSAPSS:
pubKey, ok := pubkey.(*rsa.PublicKey)
if !ok {
return fmt.Errorf("expected an RSA public key, got %T", pubkey)
}
signOpts := &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash}
if err := rsa.VerifyPSS(pubKey, hashFunc, signed, sig, signOpts); err != nil {
return err
}
default:
return errors.New("internal error: unknown signature type")
}
return nil
}
const (
serverSignatureContext = "TLS 1.3, server CertificateVerify\x00"
clientSignatureContext = "TLS 1.3, client CertificateVerify\x00"
)
var signaturePadding = []byte{
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
}
// signedMessage returns the pre-hashed (if necessary) message to be signed by
// certificate keys in TLS 1.3. See RFC 8446, Section 4.4.3.
func signedMessage(sigHash crypto.Hash, context string, transcript hash.Hash) []byte {
if sigHash == directSigning {
b := &bytes.Buffer{}
b.Write(signaturePadding)
io.WriteString(b, context)
b.Write(transcript.Sum(nil))
return b.Bytes()
}
h := sigHash.New()
h.Write(signaturePadding)
io.WriteString(h, context)
h.Write(transcript.Sum(nil))
return h.Sum(nil)
}
// typeAndHashFromSignatureScheme returns the corresponding signature type and
// crypto.Hash for a given TLS SignatureScheme.
func typeAndHashFromSignatureScheme(signatureAlgorithm SignatureScheme) (sigType uint8, hash crypto.Hash, err error) {
switch signatureAlgorithm {
case PKCS1WithSHA1, PKCS1WithSHA256, PKCS1WithSHA384, PKCS1WithSHA512:
sigType = signaturePKCS1v15
case PSSWithSHA256, PSSWithSHA384, PSSWithSHA512:
sigType = signatureRSAPSS
case ECDSAWithSHA1, ECDSAWithP256AndSHA256, ECDSAWithP384AndSHA384, ECDSAWithP521AndSHA512:
sigType = signatureECDSA
case Ed25519:
sigType = signatureEd25519
default:
return 0, 0, fmt.Errorf("unsupported signature algorithm: %v", signatureAlgorithm)
}
switch signatureAlgorithm {
case PKCS1WithSHA1, ECDSAWithSHA1:
hash = crypto.SHA1
case PKCS1WithSHA256, PSSWithSHA256, ECDSAWithP256AndSHA256:
hash = crypto.SHA256
case PKCS1WithSHA384, PSSWithSHA384, ECDSAWithP384AndSHA384:
hash = crypto.SHA384
case PKCS1WithSHA512, PSSWithSHA512, ECDSAWithP521AndSHA512:
hash = crypto.SHA512
case Ed25519:
hash = directSigning
default:
return 0, 0, fmt.Errorf("unsupported signature algorithm: %v", signatureAlgorithm)
}
return sigType, hash, nil
}
// legacyTypeAndHashFromPublicKey returns the fixed signature type and crypto.Hash for
// a given public key used with TLS 1.0 and 1.1, before the introduction of
// signature algorithm negotiation.
func legacyTypeAndHashFromPublicKey(pub crypto.PublicKey) (sigType uint8, hash crypto.Hash, err error) {
switch pub.(type) {
case *rsa.PublicKey:
return signaturePKCS1v15, crypto.MD5SHA1, nil
case *ecdsa.PublicKey:
return signatureECDSA, crypto.SHA1, nil
case ed25519.PublicKey:
// RFC 8422 specifies support for Ed25519 in TLS 1.0 and 1.1,
// but it requires holding on to a handshake transcript to do a
// full signature, and not even OpenSSL bothers with the
// complexity, so we can't even test it properly.
return 0, 0, fmt.Errorf("tls: Ed25519 public keys are not supported before TLS 1.2")
default:
return 0, 0, fmt.Errorf("tls: unsupported public key: %T", pub)
}
}
var rsaSignatureSchemes = []struct {
scheme SignatureScheme
minModulusBytes int
maxVersion uint16
}{
// RSA-PSS is used with PSSSaltLengthEqualsHash, and requires
// emLen >= hLen + sLen + 2
{PSSWithSHA256, crypto.SHA256.Size()*2 + 2, VersionTLS13},
{PSSWithSHA384, crypto.SHA384.Size()*2 + 2, VersionTLS13},
{PSSWithSHA512, crypto.SHA512.Size()*2 + 2, VersionTLS13},
// PKCS #1 v1.5 uses prefixes from hashPrefixes in crypto/rsa, and requires
// emLen >= len(prefix) + hLen + 11
// TLS 1.3 dropped support for PKCS #1 v1.5 in favor of RSA-PSS.
{PKCS1WithSHA256, 19 + crypto.SHA256.Size() + 11, VersionTLS12},
{PKCS1WithSHA384, 19 + crypto.SHA384.Size() + 11, VersionTLS12},
{PKCS1WithSHA512, 19 + crypto.SHA512.Size() + 11, VersionTLS12},
{PKCS1WithSHA1, 15 + crypto.SHA1.Size() + 11, VersionTLS12},
}
// signatureSchemesForCertificate returns the list of supported SignatureSchemes
// for a given certificate, based on the public key and the protocol version,
// and optionally filtered by its explicit SupportedSignatureAlgorithms.
//
// This function must be kept in sync with supportedSignatureAlgorithms.
// FIPS filtering is applied in the caller, selectSignatureScheme.
func signatureSchemesForCertificate(version uint16, cert *Certificate) []SignatureScheme {
priv, ok := cert.PrivateKey.(crypto.Signer)
if !ok {
return nil
}
var sigAlgs []SignatureScheme
switch pub := priv.Public().(type) {
case *ecdsa.PublicKey:
if version != VersionTLS13 {
// In TLS 1.2 and earlier, ECDSA algorithms are not
// constrained to a single curve.
sigAlgs = []SignatureScheme{
ECDSAWithP256AndSHA256,
ECDSAWithP384AndSHA384,
ECDSAWithP521AndSHA512,
ECDSAWithSHA1,
}
break
}
switch pub.Curve {
case elliptic.P256():
sigAlgs = []SignatureScheme{ECDSAWithP256AndSHA256}
case elliptic.P384():
sigAlgs = []SignatureScheme{ECDSAWithP384AndSHA384}
case elliptic.P521():
sigAlgs = []SignatureScheme{ECDSAWithP521AndSHA512}
default:
return nil
}
case *rsa.PublicKey:
size := pub.Size()
sigAlgs = make([]SignatureScheme, 0, len(rsaSignatureSchemes))
for _, candidate := range rsaSignatureSchemes {
if size >= candidate.minModulusBytes && version <= candidate.maxVersion {
sigAlgs = append(sigAlgs, candidate.scheme)
}
}
case ed25519.PublicKey:
sigAlgs = []SignatureScheme{Ed25519}
default:
return nil
}
if cert.SupportedSignatureAlgorithms != nil {
var filteredSigAlgs []SignatureScheme
for _, sigAlg := range sigAlgs {
if isSupportedSignatureAlgorithm(sigAlg, cert.SupportedSignatureAlgorithms) {
filteredSigAlgs = append(filteredSigAlgs, sigAlg)
}
}
return filteredSigAlgs
}
return sigAlgs
}
// selectSignatureScheme picks a SignatureScheme from the peer's preference list
// that works with the selected certificate. It's only called for protocol
// versions that support signature algorithms, so TLS 1.2 and 1.3.
func selectSignatureScheme(vers uint16, c *Certificate, peerAlgs []SignatureScheme) (SignatureScheme, error) {
supportedAlgs := signatureSchemesForCertificate(vers, c)
if len(supportedAlgs) == 0 {
return 0, unsupportedCertificateError(c)
}
if len(peerAlgs) == 0 && vers == VersionTLS12 {
// For TLS 1.2, if the client didn't send signature_algorithms then we
// can assume that it supports SHA1. See RFC 5246, Section 7.4.1.4.1.
peerAlgs = []SignatureScheme{PKCS1WithSHA1, ECDSAWithSHA1}
}
// Pick signature scheme in the peer's preference order, as our
// preference order is not configurable.
for _, preferredAlg := range peerAlgs {
if needFIPS() && !isSupportedSignatureAlgorithm(preferredAlg, defaultSupportedSignatureAlgorithmsFIPS) {
continue
}
if isSupportedSignatureAlgorithm(preferredAlg, supportedAlgs) {
return preferredAlg, nil
}
}
return 0, errors.New("tls: peer doesn't support any of the certificate's signature algorithms")
}
// unsupportedCertificateError returns a helpful error for certificates with
// an unsupported private key.
func unsupportedCertificateError(cert *Certificate) error {
switch cert.PrivateKey.(type) {
case rsa.PrivateKey, ecdsa.PrivateKey:
return fmt.Errorf("tls: unsupported certificate: private key is %T, expected *%T",
cert.PrivateKey, cert.PrivateKey)
case *ed25519.PrivateKey:
return fmt.Errorf("tls: unsupported certificate: private key is *ed25519.PrivateKey, expected ed25519.PrivateKey")
}
signer, ok := cert.PrivateKey.(crypto.Signer)
if !ok {
return fmt.Errorf("tls: certificate private key (%T) does not implement crypto.Signer",
cert.PrivateKey)
}
switch pub := signer.Public().(type) {
case *ecdsa.PublicKey:
switch pub.Curve {
case elliptic.P256():
case elliptic.P384():
case elliptic.P521():
default:
return fmt.Errorf("tls: unsupported certificate curve (%s)", pub.Curve.Params().Name)
}
case *rsa.PublicKey:
return fmt.Errorf("tls: certificate RSA key size too small for supported signature algorithms")
case ed25519.PublicKey:
default:
return fmt.Errorf("tls: unsupported certificate key (%T)", pub)
}
if cert.SupportedSignatureAlgorithms != nil {
return fmt.Errorf("tls: peer doesn't support the certificate custom signature algorithms")
}
return fmt.Errorf("tls: internal error: unsupported key (%T)", cert.PrivateKey)
}

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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build boringcrypto
package tls
import "crypto/internal/boring/fipstls"
// needFIPS returns fipstls.Required(), which is not available without the
// boringcrypto build tag.
func needFIPS() bool {
return fipstls.Required()
}

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// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto/x509"
"runtime"
"sync"
"sync/atomic"
)
type cacheEntry struct {
refs atomic.Int64
cert *x509.Certificate
}
// certCache implements an intern table for reference counted x509.Certificates,
// implemented in a similar fashion to BoringSSL's CRYPTO_BUFFER_POOL. This
// allows for a single x509.Certificate to be kept in memory and referenced from
// multiple Conns. Returned references should not be mutated by callers. Certificates
// are still safe to use after they are removed from the cache.
//
// Certificates are returned wrapped in an activeCert struct that should be held by
// the caller. When references to the activeCert are freed, the number of references
// to the certificate in the cache is decremented. Once the number of references
// reaches zero, the entry is evicted from the cache.
//
// The main difference between this implementation and CRYPTO_BUFFER_POOL is that
// CRYPTO_BUFFER_POOL is a more generic structure which supports blobs of data,
// rather than specific structures. Since we only care about x509.Certificates,
// certCache is implemented as a specific cache, rather than a generic one.
//
// See https://boringssl.googlesource.com/boringssl/+/master/include/openssl/pool.h
// and https://boringssl.googlesource.com/boringssl/+/master/crypto/pool/pool.c
// for the BoringSSL reference.
type certCache struct {
sync.Map
}
var globalCertCache = new(certCache)
// activeCert is a handle to a certificate held in the cache. Once there are
// no alive activeCerts for a given certificate, the certificate is removed
// from the cache by a finalizer.
type activeCert struct {
cert *x509.Certificate
}
// active increments the number of references to the entry, wraps the
// certificate in the entry in an activeCert, and sets the finalizer.
//
// Note that there is a race between active and the finalizer set on the
// returned activeCert, triggered if active is called after the ref count is
// decremented such that refs may be > 0 when evict is called. We consider this
// safe, since the caller holding an activeCert for an entry that is no longer
// in the cache is fine, with the only side effect being the memory overhead of
// there being more than one distinct reference to a certificate alive at once.
func (cc *certCache) active(e *cacheEntry) *activeCert {
e.refs.Add(1)
a := &activeCert{e.cert}
runtime.SetFinalizer(a, func(_ *activeCert) {
if e.refs.Add(-1) == 0 {
cc.evict(e)
}
})
return a
}
// evict removes a cacheEntry from the cache.
func (cc *certCache) evict(e *cacheEntry) {
cc.Delete(string(e.cert.Raw))
}
// newCert returns a x509.Certificate parsed from der. If there is already a copy
// of the certificate in the cache, a reference to the existing certificate will
// be returned. Otherwise, a fresh certificate will be added to the cache, and
// the reference returned. The returned reference should not be mutated.
func (cc *certCache) newCert(der []byte) (*activeCert, error) {
if entry, ok := cc.Load(string(der)); ok {
return cc.active(entry.(*cacheEntry)), nil
}
cert, err := x509.ParseCertificate(der)
if err != nil {
return nil, err
}
entry := &cacheEntry{cert: cert}
if entry, loaded := cc.LoadOrStore(string(der), entry); loaded {
return cc.active(entry.(*cacheEntry)), nil
}
return cc.active(entry), nil
}

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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/hmac"
"crypto/rc4"
"crypto/sha1"
"crypto/sha256"
"fmt"
"hash"
"runtime"
_ "unsafe"
"golang.org/x/crypto/chacha20poly1305"
"golang.org/x/sys/cpu"
)
// CipherSuite is a TLS cipher suite. Note that most functions in this package
// accept and expose cipher suite IDs instead of this type.
type CipherSuite struct {
ID uint16
Name string
// Supported versions is the list of TLS protocol versions that can
// negotiate this cipher suite.
SupportedVersions []uint16
// Insecure is true if the cipher suite has known security issues
// due to its primitives, design, or implementation.
Insecure bool
}
var (
supportedUpToTLS12 = []uint16{VersionTLS10, VersionTLS11, VersionTLS12}
supportedOnlyTLS12 = []uint16{VersionTLS12}
supportedOnlyTLS13 = []uint16{VersionTLS13}
)
// CipherSuites returns a list of cipher suites currently implemented by this
// package, excluding those with security issues, which are returned by
// [InsecureCipherSuites].
//
// The list is sorted by ID. Note that the default cipher suites selected by
// this package might depend on logic that can't be captured by a static list,
// and might not match those returned by this function.
func CipherSuites() []*CipherSuite {
return []*CipherSuite{
{TLS_AES_128_GCM_SHA256, "TLS_AES_128_GCM_SHA256", supportedOnlyTLS13, false},
{TLS_AES_256_GCM_SHA384, "TLS_AES_256_GCM_SHA384", supportedOnlyTLS13, false},
{TLS_CHACHA20_POLY1305_SHA256, "TLS_CHACHA20_POLY1305_SHA256", supportedOnlyTLS13, false},
{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
{TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
{TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
}
}
// InsecureCipherSuites returns a list of cipher suites currently implemented by
// this package and which have security issues.
//
// Most applications should not use the cipher suites in this list, and should
// only use those returned by [CipherSuites].
func InsecureCipherSuites() []*CipherSuite {
// This list includes RC4, CBC_SHA256, and 3DES cipher suites. See
// cipherSuitesPreferenceOrder for details.
return []*CipherSuite{
{TLS_RSA_WITH_RC4_128_SHA, "TLS_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
{TLS_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
{TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, true},
{TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, true},
{TLS_RSA_WITH_AES_128_CBC_SHA256, "TLS_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
{TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, true},
{TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, true},
{TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
{TLS_ECDHE_RSA_WITH_RC4_128_SHA, "TLS_ECDHE_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
}
}
// CipherSuiteName returns the standard name for the passed cipher suite ID
// (e.g. "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256"), or a fallback representation
// of the ID value if the cipher suite is not implemented by this package.
func CipherSuiteName(id uint16) string {
for _, c := range CipherSuites() {
if c.ID == id {
return c.Name
}
}
for _, c := range InsecureCipherSuites() {
if c.ID == id {
return c.Name
}
}
return fmt.Sprintf("0x%04X", id)
}
const (
// suiteECDHE indicates that the cipher suite involves elliptic curve
// Diffie-Hellman. This means that it should only be selected when the
// client indicates that it supports ECC with a curve and point format
// that we're happy with.
suiteECDHE = 1 << iota
// suiteECSign indicates that the cipher suite involves an ECDSA or
// EdDSA signature and therefore may only be selected when the server's
// certificate is ECDSA or EdDSA. If this is not set then the cipher suite
// is RSA based.
suiteECSign
// suiteTLS12 indicates that the cipher suite should only be advertised
// and accepted when using TLS 1.2.
suiteTLS12
// suiteSHA384 indicates that the cipher suite uses SHA384 as the
// handshake hash.
suiteSHA384
)
// A cipherSuite is a TLS 1.0–1.2 cipher suite, and defines the key exchange
// mechanism, as well as the cipher+MAC pair or the AEAD.
type cipherSuite struct {
id uint16
// the lengths, in bytes, of the key material needed for each component.
keyLen int
macLen int
ivLen int
ka func(version uint16) keyAgreement
// flags is a bitmask of the suite* values, above.
flags int
cipher func(key, iv []byte, isRead bool) any
mac func(key []byte) hash.Hash
aead func(key, fixedNonce []byte) aead
}
var cipherSuites = []*cipherSuite{ // TODO: replace with a map, since the order doesn't matter.
{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadAESGCM},
{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
{TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12, cipherAES, macSHA256, nil},
{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, cipherAES, macSHA256, nil},
{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
{TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
{TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM},
{TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
{TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12, cipherAES, macSHA256, nil},
{TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
{TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
{TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil},
{TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, 0, cipherRC4, macSHA1, nil},
{TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE, cipherRC4, macSHA1, nil},
{TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherRC4, macSHA1, nil},
}
// selectCipherSuite returns the first TLS 1.0–1.2 cipher suite from ids which
// is also in supportedIDs and passes the ok filter.
func selectCipherSuite(ids, supportedIDs []uint16, ok func(*cipherSuite) bool) *cipherSuite {
for _, id := range ids {
candidate := cipherSuiteByID(id)
if candidate == nil || !ok(candidate) {
continue
}
for _, suppID := range supportedIDs {
if id == suppID {
return candidate
}
}
}
return nil
}
// A cipherSuiteTLS13 defines only the pair of the AEAD algorithm and hash
// algorithm to be used with HKDF. See RFC 8446, Appendix B.4.
type cipherSuiteTLS13 struct {
id uint16
keyLen int
aead func(key, fixedNonce []byte) aead
hash crypto.Hash
}
// cipherSuitesTLS13 should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
// - github.com/quic-go/quic-go
// - github.com/sagernet/quic-go
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cipherSuitesTLS13
var cipherSuitesTLS13 = []*cipherSuiteTLS13{ // TODO: replace with a map.
{TLS_AES_128_GCM_SHA256, 16, aeadAESGCMTLS13, crypto.SHA256},
{TLS_CHACHA20_POLY1305_SHA256, 32, aeadChaCha20Poly1305, crypto.SHA256},
{TLS_AES_256_GCM_SHA384, 32, aeadAESGCMTLS13, crypto.SHA384},
}
// cipherSuitesPreferenceOrder is the order in which we'll select (on the
// server) or advertise (on the client) TLS 1.0–1.2 cipher suites.
//
// Cipher suites are filtered but not reordered based on the application and
// peer's preferences, meaning we'll never select a suite lower in this list if
// any higher one is available. This makes it more defensible to keep weaker
// cipher suites enabled, especially on the server side where we get the last
// word, since there are no known downgrade attacks on cipher suites selection.
//
// The list is sorted by applying the following priority rules, stopping at the
// first (most important) applicable one:
//
// - Anything else comes before RC4
//
// RC4 has practically exploitable biases. See https://www.rc4nomore.com.
//
// - Anything else comes before CBC_SHA256
//
// SHA-256 variants of the CBC ciphersuites don't implement any Lucky13
// countermeasures. See http://www.isg.rhul.ac.uk/tls/Lucky13.html and
// https://www.imperialviolet.org/2013/02/04/luckythirteen.html.
//
// - Anything else comes before 3DES
//
// 3DES has 64-bit blocks, which makes it fundamentally susceptible to
// birthday attacks. See https://sweet32.info.
//
// - ECDHE comes before anything else
//
// Once we got the broken stuff out of the way, the most important
// property a cipher suite can have is forward secrecy. We don't
// implement FFDHE, so that means ECDHE.
//
// - AEADs come before CBC ciphers
//
// Even with Lucky13 countermeasures, MAC-then-Encrypt CBC cipher suites
// are fundamentally fragile, and suffered from an endless sequence of
// padding oracle attacks. See https://eprint.iacr.org/2015/1129,
// https://www.imperialviolet.org/2014/12/08/poodleagain.html, and
// https://blog.cloudflare.com/yet-another-padding-oracle-in-openssl-cbc-ciphersuites/.
//
// - AES comes before ChaCha20
//
// When AES hardware is available, AES-128-GCM and AES-256-GCM are faster
// than ChaCha20Poly1305.
//
// When AES hardware is not available, AES-128-GCM is one or more of: much
// slower, way more complex, and less safe (because not constant time)
// than ChaCha20Poly1305.
//
// We use this list if we think both peers have AES hardware, and
// cipherSuitesPreferenceOrderNoAES otherwise.
//
// - AES-128 comes before AES-256
//
// The only potential advantages of AES-256 are better multi-target
// margins, and hypothetical post-quantum properties. Neither apply to
// TLS, and AES-256 is slower due to its four extra rounds (which don't
// contribute to the advantages above).
//
// - ECDSA comes before RSA
//
// The relative order of ECDSA and RSA cipher suites doesn't matter,
// as they depend on the certificate. Pick one to get a stable order.
var cipherSuitesPreferenceOrder = []uint16{
// AEADs w/ ECDHE
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
// CBC w/ ECDHE
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
// AEADs w/o ECDHE
TLS_RSA_WITH_AES_128_GCM_SHA256,
TLS_RSA_WITH_AES_256_GCM_SHA384,
// CBC w/o ECDHE
TLS_RSA_WITH_AES_128_CBC_SHA,
TLS_RSA_WITH_AES_256_CBC_SHA,
// 3DES
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_RSA_WITH_3DES_EDE_CBC_SHA,
// CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
TLS_RSA_WITH_AES_128_CBC_SHA256,
// RC4
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
TLS_RSA_WITH_RC4_128_SHA,
}
var cipherSuitesPreferenceOrderNoAES = []uint16{
// ChaCha20Poly1305
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
// AES-GCM w/ ECDHE
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
// The rest of cipherSuitesPreferenceOrder.
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
TLS_RSA_WITH_AES_128_GCM_SHA256,
TLS_RSA_WITH_AES_256_GCM_SHA384,
TLS_RSA_WITH_AES_128_CBC_SHA,
TLS_RSA_WITH_AES_256_CBC_SHA,
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
TLS_RSA_WITH_AES_128_CBC_SHA256,
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
TLS_RSA_WITH_RC4_128_SHA,
}
// disabledCipherSuites are not used unless explicitly listed in Config.CipherSuites.
var disabledCipherSuites = map[uint16]bool{
// CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256: true,
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256: true,
TLS_RSA_WITH_AES_128_CBC_SHA256: true,
// RC4
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA: true,
TLS_ECDHE_RSA_WITH_RC4_128_SHA: true,
TLS_RSA_WITH_RC4_128_SHA: true,
}
// rsaKexCiphers contains the ciphers which use RSA based key exchange,
// which we also disable by default unless a GODEBUG is set.
var rsaKexCiphers = map[uint16]bool{
TLS_RSA_WITH_RC4_128_SHA: true,
TLS_RSA_WITH_3DES_EDE_CBC_SHA: true,
TLS_RSA_WITH_AES_128_CBC_SHA: true,
TLS_RSA_WITH_AES_256_CBC_SHA: true,
TLS_RSA_WITH_AES_128_CBC_SHA256: true,
TLS_RSA_WITH_AES_128_GCM_SHA256: true,
TLS_RSA_WITH_AES_256_GCM_SHA384: true,
}
// tdesCiphers contains 3DES ciphers,
// which we also disable by default unless a GODEBUG is set.
var tdesCiphers = map[uint16]bool{
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA: true,
TLS_RSA_WITH_3DES_EDE_CBC_SHA: true,
}
var (
hasGCMAsmAMD64 = cpu.X86.HasAES && cpu.X86.HasPCLMULQDQ
hasGCMAsmARM64 = cpu.ARM64.HasAES && cpu.ARM64.HasPMULL
// Keep in sync with crypto/aes/cipher_s390x.go.
hasGCMAsmS390X = cpu.S390X.HasAES && cpu.S390X.HasAESCBC && cpu.S390X.HasAESCTR &&
(cpu.S390X.HasGHASH || cpu.S390X.HasAESGCM)
hasAESGCMHardwareSupport = runtime.GOARCH == "amd64" && hasGCMAsmAMD64 ||
runtime.GOARCH == "arm64" && hasGCMAsmARM64 ||
runtime.GOARCH == "s390x" && hasGCMAsmS390X
)
var aesgcmCiphers = map[uint16]bool{
// TLS 1.2
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256: true,
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384: true,
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256: true,
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384: true,
// TLS 1.3
TLS_AES_128_GCM_SHA256: true,
TLS_AES_256_GCM_SHA384: true,
}
// aesgcmPreferred returns whether the first known cipher in the preference list
// is an AES-GCM cipher, implying the peer has hardware support for it.
func aesgcmPreferred(ciphers []uint16) bool {
for _, cID := range ciphers {
if c := cipherSuiteByID(cID); c != nil {
return aesgcmCiphers[cID]
}
if c := cipherSuiteTLS13ByID(cID); c != nil {
return aesgcmCiphers[cID]
}
}
return false
}
func cipherRC4(key, iv []byte, isRead bool) any {
cipher, _ := rc4.NewCipher(key)
return cipher
}
func cipher3DES(key, iv []byte, isRead bool) any {
block, _ := des.NewTripleDESCipher(key)
if isRead {
return cipher.NewCBCDecrypter(block, iv)
}
return cipher.NewCBCEncrypter(block, iv)
}
func cipherAES(key, iv []byte, isRead bool) any {
block, _ := aes.NewCipher(key)
if isRead {
return cipher.NewCBCDecrypter(block, iv)
}
return cipher.NewCBCEncrypter(block, iv)
}
// macSHA1 returns a SHA-1 based constant time MAC.
func macSHA1(key []byte) hash.Hash {
h := sha1.New
// The BoringCrypto SHA1 does not have a constant-time
// checksum function, so don't try to use it.
// if !boring.Enabled {
h = newConstantTimeHash(h)
//}
return hmac.New(h, key)
}
// macSHA256 returns a SHA-256 based MAC. This is only supported in TLS 1.2 and
// is currently only used in disabled-by-default cipher suites.
func macSHA256(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}
type aead interface {
cipher.AEAD
// explicitNonceLen returns the number of bytes of explicit nonce
// included in each record. This is eight for older AEADs and
// zero for modern ones.
explicitNonceLen() int
}
const (
aeadNonceLength = 12
noncePrefixLength = 4
)
// prefixNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
// each call.
type prefixNonceAEAD struct {
// nonce contains the fixed part of the nonce in the first four bytes.
nonce [aeadNonceLength]byte
aead cipher.AEAD
}
func (f *prefixNonceAEAD) NonceSize() int { return aeadNonceLength - noncePrefixLength }
func (f *prefixNonceAEAD) Overhead() int { return f.aead.Overhead() }
func (f *prefixNonceAEAD) explicitNonceLen() int { return f.NonceSize() }
func (f *prefixNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
copy(f.nonce[4:], nonce)
return f.aead.Seal(out, f.nonce[:], plaintext, additionalData)
}
func (f *prefixNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
copy(f.nonce[4:], nonce)
return f.aead.Open(out, f.nonce[:], ciphertext, additionalData)
}
// xorNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
// before each call.
type xorNonceAEAD struct {
nonceMask [aeadNonceLength]byte
aead cipher.AEAD
}
func (f *xorNonceAEAD) NonceSize() int { return 8 } // 64-bit sequence number
func (f *xorNonceAEAD) Overhead() int { return f.aead.Overhead() }
func (f *xorNonceAEAD) explicitNonceLen() int { return 0 }
func (f *xorNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
result := f.aead.Seal(out, f.nonceMask[:], plaintext, additionalData)
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
return result
}
func (f *xorNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
result, err := f.aead.Open(out, f.nonceMask[:], ciphertext, additionalData)
for i, b := range nonce {
f.nonceMask[4+i] ^= b
}
return result, err
}
func aeadAESGCM(key, noncePrefix []byte) aead {
if len(noncePrefix) != noncePrefixLength {
panic("tls: internal error: wrong nonce length")
}
aes, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
var aead cipher.AEAD
//if boring.Enabled {
// aead, err = boring.NewGCMTLS(aes)
//} else {
// boring.Unreachable()
aead, err = cipher.NewGCM(aes)
//}
if err != nil {
panic(err)
}
ret := &prefixNonceAEAD{aead: aead}
copy(ret.nonce[:], noncePrefix)
return ret
}
// aeadAESGCMTLS13 should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
// - github.com/xtls/xray-core
// - github.com/v2fly/v2ray-core
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname aeadAESGCMTLS13
func aeadAESGCMTLS13(key, nonceMask []byte) aead {
if len(nonceMask) != aeadNonceLength {
panic("tls: internal error: wrong nonce length")
}
aes, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
aead, err := cipher.NewGCM(aes)
if err != nil {
panic(err)
}
ret := &xorNonceAEAD{aead: aead}
copy(ret.nonceMask[:], nonceMask)
return ret
}
func aeadChaCha20Poly1305(key, nonceMask []byte) aead {
if len(nonceMask) != aeadNonceLength {
panic("tls: internal error: wrong nonce length")
}
aead, err := chacha20poly1305.New(key)
if err != nil {
panic(err)
}
ret := &xorNonceAEAD{aead: aead}
copy(ret.nonceMask[:], nonceMask)
return ret
}
type constantTimeHash interface {
hash.Hash
ConstantTimeSum(b []byte) []byte
}
// cthWrapper wraps any hash.Hash that implements ConstantTimeSum, and replaces
// with that all calls to Sum. It's used to obtain a ConstantTimeSum-based HMAC.
type cthWrapper struct {
h constantTimeHash
}
func (c *cthWrapper) Size() int { return c.h.Size() }
func (c *cthWrapper) BlockSize() int { return c.h.BlockSize() }
func (c *cthWrapper) Reset() { c.h.Reset() }
func (c *cthWrapper) Write(p []byte) (int, error) { return c.h.Write(p) }
func (c *cthWrapper) Sum(b []byte) []byte { return c.h.ConstantTimeSum(b) }
func newConstantTimeHash(h func() hash.Hash) func() hash.Hash {
// boring.Unreachable()
return func() hash.Hash {
return &cthWrapper{h().(constantTimeHash)}
}
}
// tls10MAC implements the TLS 1.0 MAC function. RFC 2246, Section 6.2.3.
func tls10MAC(h hash.Hash, out, seq, header, data, extra []byte) []byte {
h.Reset()
h.Write(seq)
h.Write(header)
h.Write(data)
res := h.Sum(out)
if extra != nil {
h.Write(extra)
}
return res
}
func rsaKA(version uint16) keyAgreement {
return rsaKeyAgreement{}
}
func ecdheECDSAKA(version uint16) keyAgreement {
return &ecdheKeyAgreement{
isRSA: false,
version: version,
}
}
func ecdheRSAKA(version uint16) keyAgreement {
return &ecdheKeyAgreement{
isRSA: true,
version: version,
}
}
// mutualCipherSuite returns a cipherSuite given a list of supported
// ciphersuites and the id requested by the peer.
func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
for _, id := range have {
if id == want {
return cipherSuiteByID(id)
}
}
return nil
}
func cipherSuiteByID(id uint16) *cipherSuite {
for _, cipherSuite := range cipherSuites {
if cipherSuite.id == id {
return cipherSuite
}
}
return nil
}
func mutualCipherSuiteTLS13(have []uint16, want uint16) *cipherSuiteTLS13 {
for _, id := range have {
if id == want {
return cipherSuiteTLS13ByID(id)
}
}
return nil
}
func cipherSuiteTLS13ByID(id uint16) *cipherSuiteTLS13 {
for _, cipherSuite := range cipherSuitesTLS13 {
if cipherSuite.id == id {
return cipherSuite
}
}
return nil
}
// A list of cipher suite IDs that are, or have been, implemented by this
// package.
//
// See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
const (
// TLS 1.0 - 1.2 cipher suites.
TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a
TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035
TLS_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0x003c
TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c
TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a
TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc027
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca8
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca9
// TLS 1.3 cipher suites.
TLS_AES_128_GCM_SHA256 uint16 = 0x1301
TLS_AES_256_GCM_SHA384 uint16 = 0x1302
TLS_CHACHA20_POLY1305_SHA256 uint16 = 0x1303
// TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
// that the client is doing version fallback. See RFC 7507.
TLS_FALLBACK_SCSV uint16 = 0x5600
// Legacy names for the corresponding cipher suites with the correct _SHA256
// suffix, retained for backward compatibility.
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
)

1643
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@ -0,0 +1,120 @@
// Code generated by "stringer -linecomment -type=SignatureScheme,CurveID,ClientAuthType -output=common_string.go"; DO NOT EDIT.
package tls
import "strconv"
func _() {
// An "invalid array index" compiler error signifies that the constant values have changed.
// Re-run the stringer command to generate them again.
var x [1]struct{}
_ = x[PKCS1WithSHA256-1025]
_ = x[PKCS1WithSHA384-1281]
_ = x[PKCS1WithSHA512-1537]
_ = x[PSSWithSHA256-2052]
_ = x[PSSWithSHA384-2053]
_ = x[PSSWithSHA512-2054]
_ = x[ECDSAWithP256AndSHA256-1027]
_ = x[ECDSAWithP384AndSHA384-1283]
_ = x[ECDSAWithP521AndSHA512-1539]
_ = x[Ed25519-2055]
_ = x[PKCS1WithSHA1-513]
_ = x[ECDSAWithSHA1-515]
}
const (
_SignatureScheme_name_0 = "PKCS1WithSHA1"
_SignatureScheme_name_1 = "ECDSAWithSHA1"
_SignatureScheme_name_2 = "PKCS1WithSHA256"
_SignatureScheme_name_3 = "ECDSAWithP256AndSHA256"
_SignatureScheme_name_4 = "PKCS1WithSHA384"
_SignatureScheme_name_5 = "ECDSAWithP384AndSHA384"
_SignatureScheme_name_6 = "PKCS1WithSHA512"
_SignatureScheme_name_7 = "ECDSAWithP521AndSHA512"
_SignatureScheme_name_8 = "PSSWithSHA256PSSWithSHA384PSSWithSHA512Ed25519"
)
var (
_SignatureScheme_index_8 = [...]uint8{0, 13, 26, 39, 46}
)
func (i SignatureScheme) String() string {
switch {
case i == 513:
return _SignatureScheme_name_0
case i == 515:
return _SignatureScheme_name_1
case i == 1025:
return _SignatureScheme_name_2
case i == 1027:
return _SignatureScheme_name_3
case i == 1281:
return _SignatureScheme_name_4
case i == 1283:
return _SignatureScheme_name_5
case i == 1537:
return _SignatureScheme_name_6
case i == 1539:
return _SignatureScheme_name_7
case 2052 <= i && i <= 2055:
i -= 2052
return _SignatureScheme_name_8[_SignatureScheme_index_8[i]:_SignatureScheme_index_8[i+1]]
default:
return "SignatureScheme(" + strconv.FormatInt(int64(i), 10) + ")"
}
}
func _() {
// An "invalid array index" compiler error signifies that the constant values have changed.
// Re-run the stringer command to generate them again.
var x [1]struct{}
_ = x[CurveP256-23]
_ = x[CurveP384-24]
_ = x[CurveP521-25]
_ = x[X25519-29]
_ = x[x25519Kyber768Draft00-25497]
}
const (
_CurveID_name_0 = "CurveP256CurveP384CurveP521"
_CurveID_name_1 = "X25519"
_CurveID_name_2 = "X25519Kyber768Draft00"
)
var (
_CurveID_index_0 = [...]uint8{0, 9, 18, 27}
)
func (i CurveID) String() string {
switch {
case 23 <= i && i <= 25:
i -= 23
return _CurveID_name_0[_CurveID_index_0[i]:_CurveID_index_0[i+1]]
case i == 29:
return _CurveID_name_1
case i == 25497:
return _CurveID_name_2
default:
return "CurveID(" + strconv.FormatInt(int64(i), 10) + ")"
}
}
func _() {
// An "invalid array index" compiler error signifies that the constant values have changed.
// Re-run the stringer command to generate them again.
var x [1]struct{}
_ = x[NoClientCert-0]
_ = x[RequestClientCert-1]
_ = x[RequireAnyClientCert-2]
_ = x[VerifyClientCertIfGiven-3]
_ = x[RequireAndVerifyClientCert-4]
}
const _ClientAuthType_name = "NoClientCertRequestClientCertRequireAnyClientCertVerifyClientCertIfGivenRequireAndVerifyClientCert"
var _ClientAuthType_index = [...]uint8{0, 12, 29, 49, 72, 98}
func (i ClientAuthType) String() string {
if i < 0 || i >= ClientAuthType(len(_ClientAuthType_index)-1) {
return "ClientAuthType(" + strconv.FormatInt(int64(i), 10) + ")"
}
return _ClientAuthType_name[_ClientAuthType_index[i]:_ClientAuthType_index[i+1]]
}

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// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
_ "unsafe"
"golang.org/x/exp/slices"
)
func defaultCurvePreferences() []CurveID {
return []CurveID{X25519, CurveP256, CurveP384, CurveP521}
}
// defaultSupportedSignatureAlgorithms contains the signature and hash algorithms that
// the code advertises as supported in a TLS 1.2+ ClientHello and in a TLS 1.2+
// CertificateRequest. The two fields are merged to match with TLS 1.3.
// Note that in TLS 1.2, the ECDSA algorithms are not constrained to P-256, etc.
var defaultSupportedSignatureAlgorithms = []SignatureScheme{
PSSWithSHA256,
ECDSAWithP256AndSHA256,
Ed25519,
PSSWithSHA384,
PSSWithSHA512,
PKCS1WithSHA256,
PKCS1WithSHA384,
PKCS1WithSHA512,
ECDSAWithP384AndSHA384,
ECDSAWithP521AndSHA512,
PKCS1WithSHA1,
ECDSAWithSHA1,
}
func defaultCipherSuites() []uint16 {
suites := slices.Clone(cipherSuitesPreferenceOrder)
return slices.DeleteFunc(suites, func(c uint16) bool {
return disabledCipherSuites[c]
})
}
// defaultCipherSuitesTLS13 is also the preference order, since there are no
// disabled by default TLS 1.3 cipher suites. The same AES vs ChaCha20 logic as
// cipherSuitesPreferenceOrder applies.
//
// defaultCipherSuitesTLS13 should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
// - github.com/quic-go/quic-go
// - github.com/sagernet/quic-go
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname defaultCipherSuitesTLS13
var defaultCipherSuitesTLS13 = []uint16{
TLS_AES_128_GCM_SHA256,
TLS_AES_256_GCM_SHA384,
TLS_CHACHA20_POLY1305_SHA256,
}
// defaultCipherSuitesTLS13NoAES should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
// - github.com/quic-go/quic-go
// - github.com/sagernet/quic-go
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname defaultCipherSuitesTLS13NoAES
var defaultCipherSuitesTLS13NoAES = []uint16{
TLS_CHACHA20_POLY1305_SHA256,
TLS_AES_128_GCM_SHA256,
TLS_AES_256_GCM_SHA384,
}
var defaultSupportedVersionsFIPS = []uint16{
VersionTLS12,
}
// defaultCurvePreferencesFIPS are the FIPS-allowed curves,
// in preference order (most preferable first).
var defaultCurvePreferencesFIPS = []CurveID{CurveP256, CurveP384, CurveP521}
// defaultSupportedSignatureAlgorithmsFIPS currently are a subset of
// defaultSupportedSignatureAlgorithms without Ed25519 and SHA-1.
var defaultSupportedSignatureAlgorithmsFIPS = []SignatureScheme{
PSSWithSHA256,
PSSWithSHA384,
PSSWithSHA512,
PKCS1WithSHA256,
ECDSAWithP256AndSHA256,
PKCS1WithSHA384,
ECDSAWithP384AndSHA384,
PKCS1WithSHA512,
ECDSAWithP521AndSHA512,
}
// defaultCipherSuitesFIPS are the FIPS-allowed cipher suites.
var defaultCipherSuitesFIPS = []uint16{
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
TLS_RSA_WITH_AES_128_GCM_SHA256,
TLS_RSA_WITH_AES_256_GCM_SHA384,
}
// defaultCipherSuitesTLS13FIPS are the FIPS-allowed cipher suites for TLS 1.3.
var defaultCipherSuitesTLS13FIPS = []uint16{
TLS_AES_128_GCM_SHA256,
TLS_AES_256_GCM_SHA384,
}

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// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"errors"
"strings"
"github.com/sagernet/sing-shadowtls/internal/hpke"
"github.com/sagernet/sing/common"
"golang.org/x/crypto/cryptobyte"
)
type echCipher struct {
KDFID uint16
AEADID uint16
}
type echExtension struct {
Type uint16
Data []byte
}
type echConfig struct {
raw []byte
Version uint16
Length uint16
ConfigID uint8
KemID uint16
PublicKey []byte
SymmetricCipherSuite []echCipher
MaxNameLength uint8
PublicName []byte
Extensions []echExtension
}
var errMalformedECHConfig = errors.New("tls: malformed ECHConfigList")
// parseECHConfigList parses a draft-ietf-tls-esni-18 ECHConfigList, returning a
// slice of parsed ECHConfigs, in the same order they were parsed, or an error
// if the list is malformed.
func parseECHConfigList(data []byte) ([]echConfig, error) {
s := cryptobyte.String(data)
// Skip the length prefix
var length uint16
if !s.ReadUint16(&length) {
return nil, errMalformedECHConfig
}
if length != uint16(len(data)-2) {
return nil, errMalformedECHConfig
}
var configs []echConfig
for len(s) > 0 {
var ec echConfig
ec.raw = []byte(s)
if !s.ReadUint16(&ec.Version) {
return nil, errMalformedECHConfig
}
if !s.ReadUint16(&ec.Length) {
return nil, errMalformedECHConfig
}
if len(ec.raw) < int(ec.Length)+4 {
return nil, errMalformedECHConfig
}
ec.raw = ec.raw[:ec.Length+4]
if ec.Version != extensionEncryptedClientHello {
s.Skip(int(ec.Length))
continue
}
if !s.ReadUint8(&ec.ConfigID) {
return nil, errMalformedECHConfig
}
if !s.ReadUint16(&ec.KemID) {
return nil, errMalformedECHConfig
}
if !s.ReadUint16LengthPrefixed((*cryptobyte.String)(&ec.PublicKey)) {
return nil, errMalformedECHConfig
}
var cipherSuites cryptobyte.String
if !s.ReadUint16LengthPrefixed(&cipherSuites) {
return nil, errMalformedECHConfig
}
for !cipherSuites.Empty() {
var c echCipher
if !cipherSuites.ReadUint16(&c.KDFID) {
return nil, errMalformedECHConfig
}
if !cipherSuites.ReadUint16(&c.AEADID) {
return nil, errMalformedECHConfig
}
ec.SymmetricCipherSuite = append(ec.SymmetricCipherSuite, c)
}
if !s.ReadUint8(&ec.MaxNameLength) {
return nil, errMalformedECHConfig
}
var publicName cryptobyte.String
if !s.ReadUint8LengthPrefixed(&publicName) {
return nil, errMalformedECHConfig
}
ec.PublicName = publicName
var extensions cryptobyte.String
if !s.ReadUint16LengthPrefixed(&extensions) {
return nil, errMalformedECHConfig
}
for !extensions.Empty() {
var e echExtension
if !extensions.ReadUint16(&e.Type) {
return nil, errMalformedECHConfig
}
if !extensions.ReadUint16LengthPrefixed((*cryptobyte.String)(&e.Data)) {
return nil, errMalformedECHConfig
}
ec.Extensions = append(ec.Extensions, e)
}
configs = append(configs, ec)
}
return configs, nil
}
func pickECHConfig(list []echConfig) *echConfig {
for _, ec := range list {
if _, ok := hpke.SupportedKEMs[ec.KemID]; !ok {
continue
}
var validSCS bool
for _, cs := range ec.SymmetricCipherSuite {
if _, ok := hpke.SupportedAEADs[cs.AEADID]; !ok {
continue
}
if _, ok := hpke.SupportedKDFs[cs.KDFID]; !ok {
continue
}
validSCS = true
break
}
if !validSCS {
continue
}
if !validDNSName(string(ec.PublicName)) {
continue
}
var unsupportedExt bool
for _, ext := range ec.Extensions {
// If high order bit is set to 1 the extension is mandatory.
// Since we don't support any extensions, if we see a mandatory
// bit, we skip the config.
if ext.Type&uint16(1<<15) != 0 {
unsupportedExt = true
}
}
if unsupportedExt {
continue
}
return &ec
}
return nil
}
func pickECHCipherSuite(suites []echCipher) (echCipher, error) {
for _, s := range suites {
// NOTE: all of the supported AEADs and KDFs are fine, rather than
// imposing some sort of preference here, we just pick the first valid
// suite.
if _, ok := hpke.SupportedAEADs[s.AEADID]; !ok {
continue
}
if _, ok := hpke.SupportedKDFs[s.KDFID]; !ok {
continue
}
return s, nil
}
return echCipher{}, errors.New("tls: no supported symmetric ciphersuites for ECH")
}
func encodeInnerClientHello(inner *clientHelloMsg, maxNameLength int) ([]byte, error) {
h, err := inner.marshalMsg(true)
if err != nil {
return nil, err
}
h = h[4:] // strip four byte prefix
var paddingLen int
if inner.serverName != "" {
paddingLen = common.Max(0, maxNameLength-len(inner.serverName))
} else {
paddingLen = maxNameLength + 9
}
paddingLen = 31 - ((len(h) + paddingLen - 1) % 32)
return append(h, make([]byte, paddingLen)...), nil
}
func generateOuterECHExt(id uint8, kdfID, aeadID uint16, encodedKey []byte, payload []byte) ([]byte, error) {
var b cryptobyte.Builder
b.AddUint8(0) // outer
b.AddUint16(kdfID)
b.AddUint16(aeadID)
b.AddUint8(id)
b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) { b.AddBytes(encodedKey) })
b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) { b.AddBytes(payload) })
return b.Bytes()
}
func computeAndUpdateOuterECHExtension(outer, inner *clientHelloMsg, ech *echContext, useKey bool) error {
var encapKey []byte
if useKey {
encapKey = ech.encapsulatedKey
}
encodedInner, err := encodeInnerClientHello(inner, int(ech.config.MaxNameLength))
if err != nil {
return err
}
// NOTE: the tag lengths for all of the supported AEADs are the same (16
// bytes), so we have hardcoded it here. If we add support for another AEAD
// with a different tag length, we will need to change this.
encryptedLen := len(encodedInner) + 16 // AEAD tag length
outer.encryptedClientHello, err = generateOuterECHExt(ech.config.ConfigID, ech.kdfID, ech.aeadID, encapKey, make([]byte, encryptedLen))
if err != nil {
return err
}
serializedOuter, err := outer.marshal()
if err != nil {
return err
}
serializedOuter = serializedOuter[4:] // strip the four byte prefix
encryptedInner, err := ech.hpkeContext.Seal(serializedOuter, encodedInner)
if err != nil {
return err
}
outer.encryptedClientHello, err = generateOuterECHExt(ech.config.ConfigID, ech.kdfID, ech.aeadID, encapKey, encryptedInner)
if err != nil {
return err
}
return nil
}
// validDNSName is a rather rudimentary check for the validity of a DNS name.
// This is used to check if the public_name in a ECHConfig is valid when we are
// picking a config. This can be somewhat lax because even if we pick a
// valid-looking name, the DNS layer will later reject it anyway.
func validDNSName(name string) bool {
if len(name) > 253 {
return false
}
labels := strings.Split(name, ".")
if len(labels) <= 1 {
return false
}
for _, l := range labels {
labelLen := len(l)
if labelLen == 0 {
return false
}
for i, r := range l {
if r == '-' && (i == 0 || i == labelLen-1) {
return false
}
if (r < '0' || r > '9') && (r < 'a' || r > 'z') && (r < 'A' || r > 'Z') && r != '-' {
return false
}
}
}
return true
}
// ECHRejectionError is the error type returned when ECH is rejected by a remote
// server. If the server offered a ECHConfigList to use for retries, the
// RetryConfigList field will contain this list.
//
// The client may treat an ECHRejectionError with an empty set of RetryConfigs
// as a secure signal from the server.
type ECHRejectionError struct {
RetryConfigList []byte
}
func (e *ECHRejectionError) Error() string {
return "tls: server rejected ECH"
}

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build ignore
// Generate a self-signed X.509 certificate for a TLS server. Outputs to
// 'cert.pem' and 'key.pem' and will overwrite existing files.
package main
import (
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"flag"
"log"
"math/big"
"net"
"os"
"strings"
"time"
)
var (
host = flag.String("host", "", "Comma-separated hostnames and IPs to generate a certificate for")
validFrom = flag.String("start-date", "", "Creation date formatted as Jan 1 15:04:05 2011")
validFor = flag.Duration("duration", 365*24*time.Hour, "Duration that certificate is valid for")
isCA = flag.Bool("ca", false, "whether this cert should be its own Certificate Authority")
rsaBits = flag.Int("rsa-bits", 2048, "Size of RSA key to generate. Ignored if --ecdsa-curve is set")
ecdsaCurve = flag.String("ecdsa-curve", "", "ECDSA curve to use to generate a key. Valid values are P224, P256 (recommended), P384, P521")
ed25519Key = flag.Bool("ed25519", false, "Generate an Ed25519 key")
)
func publicKey(priv any) any {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &k.PublicKey
case *ecdsa.PrivateKey:
return &k.PublicKey
case ed25519.PrivateKey:
return k.Public().(ed25519.PublicKey)
default:
return nil
}
}
func main() {
flag.Parse()
if len(*host) == 0 {
log.Fatalf("Missing required --host parameter")
}
var priv any
var err error
switch *ecdsaCurve {
case "":
if *ed25519Key {
_, priv, err = ed25519.GenerateKey(rand.Reader)
} else {
priv, err = rsa.GenerateKey(rand.Reader, *rsaBits)
}
case "P224":
priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
case "P256":
priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
case "P384":
priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
case "P521":
priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
default:
log.Fatalf("Unrecognized elliptic curve: %q", *ecdsaCurve)
}
if err != nil {
log.Fatalf("Failed to generate private key: %v", err)
}
// ECDSA, ED25519 and RSA subject keys should have the DigitalSignature
// KeyUsage bits set in the x509.Certificate template
keyUsage := x509.KeyUsageDigitalSignature
// Only RSA subject keys should have the KeyEncipherment KeyUsage bits set. In
// the context of TLS this KeyUsage is particular to RSA key exchange and
// authentication.
if _, isRSA := priv.(*rsa.PrivateKey); isRSA {
keyUsage |= x509.KeyUsageKeyEncipherment
}
var notBefore time.Time
if len(*validFrom) == 0 {
notBefore = time.Now()
} else {
notBefore, err = time.Parse("Jan 2 15:04:05 2006", *validFrom)
if err != nil {
log.Fatalf("Failed to parse creation date: %v", err)
}
}
notAfter := notBefore.Add(*validFor)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
if err != nil {
log.Fatalf("Failed to generate serial number: %v", err)
}
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"Acme Co"},
},
NotBefore: notBefore,
NotAfter: notAfter,
KeyUsage: keyUsage,
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
hosts := strings.Split(*host, ",")
for _, h := range hosts {
if ip := net.ParseIP(h); ip != nil {
template.IPAddresses = append(template.IPAddresses, ip)
} else {
template.DNSNames = append(template.DNSNames, h)
}
}
if *isCA {
template.IsCA = true
template.KeyUsage |= x509.KeyUsageCertSign
}
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
if err != nil {
log.Fatalf("Failed to create certificate: %v", err)
}
certOut, err := os.Create("cert.pem")
if err != nil {
log.Fatalf("Failed to open cert.pem for writing: %v", err)
}
if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
log.Fatalf("Failed to write data to cert.pem: %v", err)
}
if err := certOut.Close(); err != nil {
log.Fatalf("Error closing cert.pem: %v", err)
}
log.Print("wrote cert.pem\n")
keyOut, err := os.OpenFile("key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o600)
if err != nil {
log.Fatalf("Failed to open key.pem for writing: %v", err)
}
privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
if err != nil {
log.Fatalf("Unable to marshal private key: %v", err)
}
if err := pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
log.Fatalf("Failed to write data to key.pem: %v", err)
}
if err := keyOut.Close(); err != nil {
log.Fatalf("Error closing key.pem: %v", err)
}
log.Print("wrote key.pem\n")
}

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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"bytes"
"context"
"crypto"
"crypto/hmac"
"crypto/rsa"
"crypto/subtle"
"errors"
"hash"
"time"
"github.com/sagernet/sing-shadowtls/internal/mlkem768"
"golang.org/x/exp/slices"
)
type clientHandshakeStateTLS13 struct {
c *Conn
ctx context.Context
serverHello *serverHelloMsg
hello *clientHelloMsg
keyShareKeys *keySharePrivateKeys
session *SessionState
earlySecret []byte
binderKey []byte
certReq *certificateRequestMsgTLS13
usingPSK bool
sentDummyCCS bool
suite *cipherSuiteTLS13
transcript hash.Hash
masterSecret []byte
trafficSecret []byte // client_application_traffic_secret_0
echContext *echContext
}
// handshake requires hs.c, hs.hello, hs.serverHello, hs.keyShareKeys, and,
// optionally, hs.session, hs.earlySecret and hs.binderKey to be set.
func (hs *clientHandshakeStateTLS13) handshake() error {
c := hs.c
if needFIPS() {
return errors.New("tls: internal error: TLS 1.3 reached in FIPS mode")
}
// The server must not select TLS 1.3 in a renegotiation. See RFC 8446,
// sections 4.1.2 and 4.1.3.
if c.handshakes > 0 {
c.sendAlert(alertProtocolVersion)
return errors.New("tls: server selected TLS 1.3 in a renegotiation")
}
// Consistency check on the presence of a keyShare and its parameters.
if hs.keyShareKeys == nil || hs.keyShareKeys.ecdhe == nil || len(hs.hello.keyShares) == 0 {
return c.sendAlert(alertInternalError)
}
if err := hs.checkServerHelloOrHRR(); err != nil {
return err
}
hs.transcript = hs.suite.hash.New()
if err := transcriptMsg(hs.hello, hs.transcript); err != nil {
return err
}
if hs.echContext != nil {
hs.echContext.innerTranscript = hs.suite.hash.New()
if err := transcriptMsg(hs.echContext.innerHello, hs.echContext.innerTranscript); err != nil {
return err
}
}
if bytes.Equal(hs.serverHello.random, helloRetryRequestRandom) {
if err := hs.sendDummyChangeCipherSpec(); err != nil {
return err
}
if err := hs.processHelloRetryRequest(); err != nil {
return err
}
}
var echRetryConfigList []byte
if hs.echContext != nil {
confTranscript := cloneHash(hs.echContext.innerTranscript, hs.suite.hash)
confTranscript.Write(hs.serverHello.original[:30])
confTranscript.Write(make([]byte, 8))
confTranscript.Write(hs.serverHello.original[38:])
acceptConfirmation := hs.suite.expandLabel(
hs.suite.extract(hs.echContext.innerHello.random, nil),
"ech accept confirmation",
confTranscript.Sum(nil),
8,
)
if subtle.ConstantTimeCompare(acceptConfirmation, hs.serverHello.random[len(hs.serverHello.random)-8:]) == 1 {
hs.hello = hs.echContext.innerHello
c.serverName = c.config.ServerName
hs.transcript = hs.echContext.innerTranscript
c.echAccepted = true
if hs.serverHello.encryptedClientHello != nil {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: unexpected encrypted_client_hello extension in server hello despite ECH being accepted")
}
if hs.hello.serverName == "" && hs.serverHello.serverNameAck {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: unexpected server_name extension in server hello")
}
} else {
hs.echContext.echRejected = true
// If the server sent us retry configs, we'll return these to
// the user so they can update their Config.
echRetryConfigList = hs.serverHello.encryptedClientHello
}
}
if err := transcriptMsg(hs.serverHello, hs.transcript); err != nil {
return err
}
c.buffering = true
if err := hs.processServerHello(); err != nil {
return err
}
if err := hs.sendDummyChangeCipherSpec(); err != nil {
return err
}
if err := hs.establishHandshakeKeys(); err != nil {
return err
}
if err := hs.readServerParameters(); err != nil {
return err
}
if err := hs.readServerCertificate(); err != nil {
return err
}
if err := hs.readServerFinished(); err != nil {
return err
}
if err := hs.sendClientCertificate(); err != nil {
return err
}
if err := hs.sendClientFinished(); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
if hs.echContext != nil && hs.echContext.echRejected {
c.sendAlert(alertECHRequired)
return &ECHRejectionError{echRetryConfigList}
}
c.isHandshakeComplete.Store(true)
return nil
}
// checkServerHelloOrHRR does validity checks that apply to both ServerHello and
// HelloRetryRequest messages. It sets hs.suite.
func (hs *clientHandshakeStateTLS13) checkServerHelloOrHRR() error {
c := hs.c
if hs.serverHello.supportedVersion == 0 {
c.sendAlert(alertMissingExtension)
return errors.New("tls: server selected TLS 1.3 using the legacy version field")
}
if hs.serverHello.supportedVersion != VersionTLS13 {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected an invalid version after a HelloRetryRequest")
}
if hs.serverHello.vers != VersionTLS12 {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server sent an incorrect legacy version")
}
if hs.serverHello.ocspStapling ||
hs.serverHello.ticketSupported ||
hs.serverHello.extendedMasterSecret ||
hs.serverHello.secureRenegotiationSupported ||
len(hs.serverHello.secureRenegotiation) != 0 ||
len(hs.serverHello.alpnProtocol) != 0 ||
len(hs.serverHello.scts) != 0 {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: server sent a ServerHello extension forbidden in TLS 1.3")
}
if !bytes.Equal(hs.hello.sessionId, hs.serverHello.sessionId) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server did not echo the legacy session ID")
}
if hs.serverHello.compressionMethod != compressionNone {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected unsupported compression format")
}
selectedSuite := mutualCipherSuiteTLS13(hs.hello.cipherSuites, hs.serverHello.cipherSuite)
if hs.suite != nil && selectedSuite != hs.suite {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server changed cipher suite after a HelloRetryRequest")
}
if selectedSuite == nil {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server chose an unconfigured cipher suite")
}
hs.suite = selectedSuite
c.cipherSuite = hs.suite.id
return nil
}
// sendDummyChangeCipherSpec sends a ChangeCipherSpec record for compatibility
// with middleboxes that didn't implement TLS correctly. See RFC 8446, Appendix D.4.
func (hs *clientHandshakeStateTLS13) sendDummyChangeCipherSpec() error {
if hs.c.quic != nil {
return nil
}
if hs.sentDummyCCS {
return nil
}
hs.sentDummyCCS = true
return hs.c.writeChangeCipherRecord()
}
// processHelloRetryRequest handles the HRR in hs.serverHello, modifies and
// resends hs.hello, and reads the new ServerHello into hs.serverHello.
func (hs *clientHandshakeStateTLS13) processHelloRetryRequest() error {
c := hs.c
// The first ClientHello gets double-hashed into the transcript upon a
// HelloRetryRequest. (The idea is that the server might offload transcript
// storage to the client in the cookie.) See RFC 8446, Section 4.4.1.
chHash := hs.transcript.Sum(nil)
hs.transcript.Reset()
hs.transcript.Write([]byte{typeMessageHash, 0, 0, uint8(len(chHash))})
hs.transcript.Write(chHash)
if err := transcriptMsg(hs.serverHello, hs.transcript); err != nil {
return err
}
var isInnerHello bool
hello := hs.hello
if hs.echContext != nil {
chHash = hs.echContext.innerTranscript.Sum(nil)
hs.echContext.innerTranscript.Reset()
hs.echContext.innerTranscript.Write([]byte{typeMessageHash, 0, 0, uint8(len(chHash))})
hs.echContext.innerTranscript.Write(chHash)
if hs.serverHello.encryptedClientHello != nil {
if len(hs.serverHello.encryptedClientHello) != 8 {
hs.c.sendAlert(alertDecodeError)
return errors.New("tls: malformed encrypted client hello extension")
}
confTranscript := cloneHash(hs.echContext.innerTranscript, hs.suite.hash)
hrrHello := make([]byte, len(hs.serverHello.original))
copy(hrrHello, hs.serverHello.original)
hrrHello = bytes.Replace(hrrHello, hs.serverHello.encryptedClientHello, make([]byte, 8), 1)
confTranscript.Write(hrrHello)
acceptConfirmation := hs.suite.expandLabel(
hs.suite.extract(hs.echContext.innerHello.random, nil),
"hrr ech accept confirmation",
confTranscript.Sum(nil),
8,
)
if subtle.ConstantTimeCompare(acceptConfirmation, hs.serverHello.encryptedClientHello) == 1 {
hello = hs.echContext.innerHello
c.serverName = c.config.ServerName
isInnerHello = true
c.echAccepted = true
}
}
if err := transcriptMsg(hs.serverHello, hs.echContext.innerTranscript); err != nil {
return err
}
} else if hs.serverHello.encryptedClientHello != nil {
// Unsolicited ECH extension should be rejected
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: unexpected ECH extension in serverHello")
}
// The only HelloRetryRequest extensions we support are key_share and
// cookie, and clients must abort the handshake if the HRR would not result
// in any change in the ClientHello.
if hs.serverHello.selectedGroup == 0 && hs.serverHello.cookie == nil {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server sent an unnecessary HelloRetryRequest message")
}
if hs.serverHello.cookie != nil {
hello.cookie = hs.serverHello.cookie
}
if hs.serverHello.serverShare.group != 0 {
c.sendAlert(alertDecodeError)
return errors.New("tls: received malformed key_share extension")
}
// If the server sent a key_share extension selecting a group, ensure it's
// a group we advertised but did not send a key share for, and send a key
// share for it this time.
if curveID := hs.serverHello.selectedGroup; curveID != 0 {
if !slices.Contains(hello.supportedCurves, curveID) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected unsupported group")
}
if slices.ContainsFunc(hs.hello.keyShares, func(ks keyShare) bool {
return ks.group == curveID
}) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server sent an unnecessary HelloRetryRequest key_share")
}
// Note: we don't support selecting X25519Kyber768Draft00 in a HRR,
// because we currently only support it at all when CurvePreferences is
// empty, which will cause us to also send a key share for it.
//
// This will have to change once we support selecting hybrid KEMs
// without sending key shares for them.
if _, ok := curveForCurveID(curveID); !ok {
c.sendAlert(alertInternalError)
return errors.New("tls: CurvePreferences includes unsupported curve")
}
key, err := generateECDHEKey(c.config.rand(), curveID)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
hs.keyShareKeys = &keySharePrivateKeys{curveID: curveID, ecdhe: key}
hello.keyShares = []keyShare{{group: curveID, data: key.PublicKey().Bytes()}}
}
if len(hello.pskIdentities) > 0 {
pskSuite := cipherSuiteTLS13ByID(hs.session.cipherSuite)
if pskSuite == nil {
return c.sendAlert(alertInternalError)
}
if pskSuite.hash == hs.suite.hash {
// Update binders and obfuscated_ticket_age.
ticketAge := c.config.time().Sub(time.Unix(int64(hs.session.createdAt), 0))
hello.pskIdentities[0].obfuscatedTicketAge = uint32(ticketAge/time.Millisecond) + hs.session.ageAdd
transcript := hs.suite.hash.New()
transcript.Write([]byte{typeMessageHash, 0, 0, uint8(len(chHash))})
transcript.Write(chHash)
if err := transcriptMsg(hs.serverHello, transcript); err != nil {
return err
}
if err := computeAndUpdatePSK(hello, hs.binderKey, transcript, hs.suite.finishedHash); err != nil {
return err
}
} else {
// Server selected a cipher suite incompatible with the PSK.
hello.pskIdentities = nil
hello.pskBinders = nil
}
}
if hello.earlyData {
hello.earlyData = false
c.quicRejectedEarlyData()
}
if isInnerHello {
// Any extensions which have changed in hello, but are mirrored in the
// outer hello and compressed, need to be copied to the outer hello, so
// they can be properly decompressed by the server. For now, the only
// extension which may have changed is keyShares.
hs.hello.keyShares = hello.keyShares
hs.echContext.innerHello = hello
if err := transcriptMsg(hs.echContext.innerHello, hs.echContext.innerTranscript); err != nil {
return err
}
if err := computeAndUpdateOuterECHExtension(hs.hello, hs.echContext.innerHello, hs.echContext, false); err != nil {
return err
}
} else {
hs.hello = hello
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, hs.transcript); err != nil {
return err
}
// serverHelloMsg is not included in the transcript
msg, err := c.readHandshake(nil)
if err != nil {
return err
}
serverHello, ok := msg.(*serverHelloMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(serverHello, msg)
}
hs.serverHello = serverHello
if err := hs.checkServerHelloOrHRR(); err != nil {
return err
}
c.didHRR = true
return nil
}
func (hs *clientHandshakeStateTLS13) processServerHello() error {
c := hs.c
if bytes.Equal(hs.serverHello.random, helloRetryRequestRandom) {
c.sendAlert(alertUnexpectedMessage)
return errors.New("tls: server sent two HelloRetryRequest messages")
}
if len(hs.serverHello.cookie) != 0 {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: server sent a cookie in a normal ServerHello")
}
if hs.serverHello.selectedGroup != 0 {
c.sendAlert(alertDecodeError)
return errors.New("tls: malformed key_share extension")
}
if hs.serverHello.serverShare.group == 0 {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server did not send a key share")
}
if !slices.ContainsFunc(hs.hello.keyShares, func(ks keyShare) bool {
return ks.group == hs.serverHello.serverShare.group
}) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected unsupported group")
}
if !hs.serverHello.selectedIdentityPresent {
return nil
}
if int(hs.serverHello.selectedIdentity) >= len(hs.hello.pskIdentities) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected an invalid PSK")
}
if len(hs.hello.pskIdentities) != 1 || hs.session == nil {
return c.sendAlert(alertInternalError)
}
pskSuite := cipherSuiteTLS13ByID(hs.session.cipherSuite)
if pskSuite == nil {
return c.sendAlert(alertInternalError)
}
if pskSuite.hash != hs.suite.hash {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: server selected an invalid PSK and cipher suite pair")
}
hs.usingPSK = true
c.didResume = true
c.peerCertificates = hs.session.peerCertificates
c.activeCertHandles = hs.session.activeCertHandles
c.verifiedChains = hs.session.verifiedChains
c.ocspResponse = hs.session.ocspResponse
c.scts = hs.session.scts
return nil
}
func (hs *clientHandshakeStateTLS13) establishHandshakeKeys() error {
c := hs.c
ecdhePeerData := hs.serverHello.serverShare.data
if hs.serverHello.serverShare.group == x25519Kyber768Draft00 {
if len(ecdhePeerData) != x25519PublicKeySize+mlkem768.CiphertextSize {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: invalid server key share")
}
ecdhePeerData = hs.serverHello.serverShare.data[:x25519PublicKeySize]
}
peerKey, err := hs.keyShareKeys.ecdhe.Curve().NewPublicKey(ecdhePeerData)
if err != nil {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: invalid server key share")
}
sharedKey, err := hs.keyShareKeys.ecdhe.ECDH(peerKey)
if err != nil {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: invalid server key share")
}
if hs.serverHello.serverShare.group == x25519Kyber768Draft00 {
if hs.keyShareKeys.kyber == nil {
return c.sendAlert(alertInternalError)
}
ciphertext := hs.serverHello.serverShare.data[x25519PublicKeySize:]
kyberShared, err := kyberDecapsulate(hs.keyShareKeys.kyber, ciphertext)
if err != nil {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: invalid Kyber server key share")
}
sharedKey = append(sharedKey, kyberShared...)
}
c.curveID = hs.serverHello.serverShare.group
earlySecret := hs.earlySecret
if !hs.usingPSK {
earlySecret = hs.suite.extract(nil, nil)
}
handshakeSecret := hs.suite.extract(sharedKey,
hs.suite.deriveSecret(earlySecret, "derived", nil))
clientSecret := hs.suite.deriveSecret(handshakeSecret,
clientHandshakeTrafficLabel, hs.transcript)
c.out.setTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, clientSecret)
serverSecret := hs.suite.deriveSecret(handshakeSecret,
serverHandshakeTrafficLabel, hs.transcript)
c.in.setTrafficSecret(hs.suite, QUICEncryptionLevelHandshake, serverSecret)
if c.quic != nil {
if c.hand.Len() != 0 {
c.sendAlert(alertUnexpectedMessage)
}
c.quicSetWriteSecret(QUICEncryptionLevelHandshake, hs.suite.id, clientSecret)
c.quicSetReadSecret(QUICEncryptionLevelHandshake, hs.suite.id, serverSecret)
}
err = c.config.writeKeyLog(keyLogLabelClientHandshake, hs.hello.random, clientSecret)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
err = c.config.writeKeyLog(keyLogLabelServerHandshake, hs.hello.random, serverSecret)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
hs.masterSecret = hs.suite.extract(nil,
hs.suite.deriveSecret(handshakeSecret, "derived", nil))
return nil
}
func (hs *clientHandshakeStateTLS13) readServerParameters() error {
c := hs.c
msg, err := c.readHandshake(hs.transcript)
if err != nil {
return err
}
encryptedExtensions, ok := msg.(*encryptedExtensionsMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(encryptedExtensions, msg)
}
if err := checkALPN(hs.hello.alpnProtocols, encryptedExtensions.alpnProtocol, c.quic != nil); err != nil {
// RFC 8446 specifies that no_application_protocol is sent by servers, but
// does not specify how clients handle the selection of an incompatible protocol.
// RFC 9001 Section 8.1 specifies that QUIC clients send no_application_protocol
// in this case. Always sending no_application_protocol seems reasonable.
c.sendAlert(alertNoApplicationProtocol)
return err
}
c.clientProtocol = encryptedExtensions.alpnProtocol
if c.quic != nil {
if encryptedExtensions.quicTransportParameters == nil {
// RFC 9001 Section 8.2.
c.sendAlert(alertMissingExtension)
return errors.New("tls: server did not send a quic_transport_parameters extension")
}
c.quicSetTransportParameters(encryptedExtensions.quicTransportParameters)
} else {
if encryptedExtensions.quicTransportParameters != nil {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: server sent an unexpected quic_transport_parameters extension")
}
}
if !hs.hello.earlyData && encryptedExtensions.earlyData {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: server sent an unexpected early_data extension")
}
if hs.hello.earlyData && !encryptedExtensions.earlyData {
c.quicRejectedEarlyData()
}
if encryptedExtensions.earlyData {
if hs.session.cipherSuite != c.cipherSuite {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: server accepted 0-RTT with the wrong cipher suite")
}
if hs.session.alpnProtocol != c.clientProtocol {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: server accepted 0-RTT with the wrong ALPN")
}
}
if hs.echContext != nil && !hs.echContext.echRejected && encryptedExtensions.echRetryConfigs != nil {
c.sendAlert(alertUnsupportedExtension)
return errors.New("tls: server sent ECH retry configs after accepting ECH")
}
return nil
}
func (hs *clientHandshakeStateTLS13) readServerCertificate() error {
c := hs.c
// Either a PSK or a certificate is always used, but not both.
// See RFC 8446, Section 4.1.1.
if hs.usingPSK {
// Make sure the connection is still being verified whether or not this
// is a resumption. Resumptions currently don't reverify certificates so
// they don't call verifyServerCertificate. See Issue 31641.
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
return nil
}
msg, err := c.readHandshake(hs.transcript)
if err != nil {
return err
}
certReq, ok := msg.(*certificateRequestMsgTLS13)
if ok {
hs.certReq = certReq
msg, err = c.readHandshake(hs.transcript)
if err != nil {
return err
}
}
certMsg, ok := msg.(*certificateMsgTLS13)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certMsg, msg)
}
if len(certMsg.certificate.Certificate) == 0 {
c.sendAlert(alertDecodeError)
return errors.New("tls: received empty certificates message")
}
c.scts = certMsg.certificate.SignedCertificateTimestamps
c.ocspResponse = certMsg.certificate.OCSPStaple
if err := c.verifyServerCertificate(certMsg.certificate.Certificate); err != nil {
return err
}
// certificateVerifyMsg is included in the transcript, but not until
// after we verify the handshake signature, since the state before
// this message was sent is used.
msg, err = c.readHandshake(nil)
if err != nil {
return err
}
certVerify, ok := msg.(*certificateVerifyMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certVerify, msg)
}
// See RFC 8446, Section 4.4.3.
if !isSupportedSignatureAlgorithm(certVerify.signatureAlgorithm, supportedSignatureAlgorithms()) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: certificate used with invalid signature algorithm")
}
sigType, sigHash, err := typeAndHashFromSignatureScheme(certVerify.signatureAlgorithm)
if err != nil {
return c.sendAlert(alertInternalError)
}
if sigType == signaturePKCS1v15 || sigHash == crypto.SHA1 {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: certificate used with invalid signature algorithm")
}
signed := signedMessage(sigHash, serverSignatureContext, hs.transcript)
if err := verifyHandshakeSignature(sigType, c.peerCertificates[0].PublicKey,
sigHash, signed, certVerify.signature); err != nil {
c.sendAlert(alertDecryptError)
return errors.New("tls: invalid signature by the server certificate: " + err.Error())
}
if err := transcriptMsg(certVerify, hs.transcript); err != nil {
return err
}
return nil
}
func (hs *clientHandshakeStateTLS13) readServerFinished() error {
c := hs.c
// finishedMsg is included in the transcript, but not until after we
// check the client version, since the state before this message was
// sent is used during verification.
msg, err := c.readHandshake(nil)
if err != nil {
return err
}
finished, ok := msg.(*finishedMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(finished, msg)
}
expectedMAC := hs.suite.finishedHash(c.in.trafficSecret, hs.transcript)
if !hmac.Equal(expectedMAC, finished.verifyData) {
c.sendAlert(alertDecryptError)
return errors.New("tls: invalid server finished hash")
}
if err := transcriptMsg(finished, hs.transcript); err != nil {
return err
}
// Derive secrets that take context through the server Finished.
hs.trafficSecret = hs.suite.deriveSecret(hs.masterSecret,
clientApplicationTrafficLabel, hs.transcript)
serverSecret := hs.suite.deriveSecret(hs.masterSecret,
serverApplicationTrafficLabel, hs.transcript)
c.in.setTrafficSecret(hs.suite, QUICEncryptionLevelApplication, serverSecret)
err = c.config.writeKeyLog(keyLogLabelClientTraffic, hs.hello.random, hs.trafficSecret)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
err = c.config.writeKeyLog(keyLogLabelServerTraffic, hs.hello.random, serverSecret)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
c.ekm = hs.suite.exportKeyingMaterial(hs.masterSecret, hs.transcript)
return nil
}
func (hs *clientHandshakeStateTLS13) sendClientCertificate() error {
c := hs.c
if hs.certReq == nil {
return nil
}
if hs.echContext != nil && hs.echContext.echRejected {
if _, err := hs.c.writeHandshakeRecord(&certificateMsgTLS13{}, hs.transcript); err != nil {
return err
}
return nil
}
cert, err := c.getClientCertificate(&CertificateRequestInfo{
AcceptableCAs: hs.certReq.certificateAuthorities,
SignatureSchemes: hs.certReq.supportedSignatureAlgorithms,
Version: c.vers,
ctx: hs.ctx,
})
if err != nil {
return err
}
certMsg := new(certificateMsgTLS13)
certMsg.certificate = *cert
certMsg.scts = hs.certReq.scts && len(cert.SignedCertificateTimestamps) > 0
certMsg.ocspStapling = hs.certReq.ocspStapling && len(cert.OCSPStaple) > 0
if _, err := hs.c.writeHandshakeRecord(certMsg, hs.transcript); err != nil {
return err
}
// If we sent an empty certificate message, skip the CertificateVerify.
if len(cert.Certificate) == 0 {
return nil
}
certVerifyMsg := new(certificateVerifyMsg)
certVerifyMsg.hasSignatureAlgorithm = true
certVerifyMsg.signatureAlgorithm, err = selectSignatureScheme(c.vers, cert, hs.certReq.supportedSignatureAlgorithms)
if err != nil {
// getClientCertificate returned a certificate incompatible with the
// CertificateRequestInfo supported signature algorithms.
c.sendAlert(alertHandshakeFailure)
return err
}
sigType, sigHash, err := typeAndHashFromSignatureScheme(certVerifyMsg.signatureAlgorithm)
if err != nil {
return c.sendAlert(alertInternalError)
}
signed := signedMessage(sigHash, clientSignatureContext, hs.transcript)
signOpts := crypto.SignerOpts(sigHash)
if sigType == signatureRSAPSS {
signOpts = &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash, Hash: sigHash}
}
sig, err := cert.PrivateKey.(crypto.Signer).Sign(c.config.rand(), signed, signOpts)
if err != nil {
c.sendAlert(alertInternalError)
return errors.New("tls: failed to sign handshake: " + err.Error())
}
certVerifyMsg.signature = sig
if _, err := hs.c.writeHandshakeRecord(certVerifyMsg, hs.transcript); err != nil {
return err
}
return nil
}
func (hs *clientHandshakeStateTLS13) sendClientFinished() error {
c := hs.c
finished := &finishedMsg{
verifyData: hs.suite.finishedHash(c.out.trafficSecret, hs.transcript),
}
if _, err := hs.c.writeHandshakeRecord(finished, hs.transcript); err != nil {
return err
}
c.out.setTrafficSecret(hs.suite, QUICEncryptionLevelApplication, hs.trafficSecret)
if !c.config.SessionTicketsDisabled && c.config.ClientSessionCache != nil {
c.resumptionSecret = hs.suite.deriveSecret(hs.masterSecret,
resumptionLabel, hs.transcript)
}
if c.quic != nil {
if c.hand.Len() != 0 {
c.sendAlert(alertUnexpectedMessage)
}
c.quicSetWriteSecret(QUICEncryptionLevelApplication, hs.suite.id, hs.trafficSecret)
}
return nil
}
func (c *Conn) handleNewSessionTicket(msg *newSessionTicketMsgTLS13) error {
if !c.isClient {
c.sendAlert(alertUnexpectedMessage)
return errors.New("tls: received new session ticket from a client")
}
if c.config.SessionTicketsDisabled || c.config.ClientSessionCache == nil {
return nil
}
// See RFC 8446, Section 4.6.1.
if msg.lifetime == 0 {
return nil
}
lifetime := time.Duration(msg.lifetime) * time.Second
if lifetime > maxSessionTicketLifetime {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: received a session ticket with invalid lifetime")
}
// RFC 9001, Section 4.6.1
if c.quic != nil && msg.maxEarlyData != 0 && msg.maxEarlyData != 0xffffffff {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: invalid early data for QUIC connection")
}
cipherSuite := cipherSuiteTLS13ByID(c.cipherSuite)
if cipherSuite == nil || c.resumptionSecret == nil {
return c.sendAlert(alertInternalError)
}
psk := cipherSuite.expandLabel(c.resumptionSecret, "resumption",
msg.nonce, cipherSuite.hash.Size())
session := c.sessionState()
session.secret = psk
session.useBy = uint64(c.config.time().Add(lifetime).Unix())
session.ageAdd = msg.ageAdd
session.EarlyData = c.quic != nil && msg.maxEarlyData == 0xffffffff // RFC 9001, Section 4.6.1
session.ticket = msg.label
if c.quic != nil && c.quic.enableSessionEvents {
c.quicStoreSession(session)
return nil
}
cs := &ClientSessionState{session: session}
if cacheKey := c.clientSessionCacheKey(); cacheKey != "" {
c.config.ClientSessionCache.Put(cacheKey, cs)
}
return nil
}

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internal/tls/handshake_server.go Normal file
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"context"
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/subtle"
"crypto/x509"
"errors"
"fmt"
"hash"
"io"
"time"
"github.com/sagernet/sing-shadowtls/internal/byteorder"
)
// serverHandshakeState contains details of a server handshake in progress.
// It's discarded once the handshake has completed.
type serverHandshakeState struct {
c *Conn
ctx context.Context
clientHello *clientHelloMsg
hello *serverHelloMsg
suite *cipherSuite
ecdheOk bool
ecSignOk bool
rsaDecryptOk bool
rsaSignOk bool
sessionState *SessionState
finishedHash finishedHash
masterSecret []byte
cert *Certificate
}
// serverHandshake performs a TLS handshake as a server.
func (c *Conn) serverHandshake(ctx context.Context) error {
clientHello, err := c.readClientHello(ctx)
if err != nil {
return err
}
if c.vers == VersionTLS13 {
hs := serverHandshakeStateTLS13{
c: c,
ctx: ctx,
clientHello: clientHello,
}
return hs.handshake()
}
hs := serverHandshakeState{
c: c,
ctx: ctx,
clientHello: clientHello,
}
return hs.handshake()
}
func (hs *serverHandshakeState) handshake() error {
c := hs.c
if err := hs.processClientHello(); err != nil {
return err
}
// For an overview of TLS handshaking, see RFC 5246, Section 7.3.
c.buffering = true
if err := hs.checkForResumption(); err != nil {
return err
}
if hs.sessionState != nil {
// The client has included a session ticket and so we do an abbreviated handshake.
if err := hs.doResumeHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(c.serverFinished[:]); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
c.clientFinishedIsFirst = false
if err := hs.readFinished(nil); err != nil {
return err
}
} else {
// The client didn't include a session ticket, or it wasn't
// valid so we do a full handshake.
if err := hs.pickCipherSuite(); err != nil {
return err
}
if err := hs.doFullHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.readFinished(c.clientFinished[:]); err != nil {
return err
}
c.clientFinishedIsFirst = true
c.buffering = true
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(nil); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
}
c.ekm = ekmFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random)
c.isHandshakeComplete.Store(true)
return nil
}
// readClientHello reads a ClientHello message and selects the protocol version.
func (c *Conn) readClientHello(ctx context.Context) (*clientHelloMsg, error) {
// clientHelloMsg is included in the transcript, but we haven't initialized
// it yet. The respective handshake functions will record it themselves.
msg, err := c.readHandshake(nil)
if err != nil {
return nil, err
}
clientHello, ok := msg.(*clientHelloMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return nil, unexpectedMessageError(clientHello, msg)
}
var configForClient *Config
originalConfig := c.config
if c.config.GetConfigForClient != nil {
chi := clientHelloInfo(ctx, c, clientHello)
if configForClient, err = c.config.GetConfigForClient(chi); err != nil {
c.sendAlert(alertInternalError)
return nil, err
} else if configForClient != nil {
c.config = configForClient
}
}
c.ticketKeys = originalConfig.ticketKeys(configForClient)
clientVersions := clientHello.supportedVersions
if len(clientHello.supportedVersions) == 0 {
clientVersions = supportedVersionsFromMax(clientHello.vers)
}
c.vers, ok = c.config.mutualVersion(roleServer, clientVersions)
if !ok {
c.sendAlert(alertProtocolVersion)
return nil, fmt.Errorf("tls: client offered only unsupported versions: %x", clientVersions)
}
c.haveVers = true
c.in.version = c.vers
c.out.version = c.vers
return clientHello, nil
}
func (hs *serverHandshakeState) processClientHello() error {
c := hs.c
hs.hello = new(serverHelloMsg)
hs.hello.vers = c.vers
foundCompression := false
// We only support null compression, so check that the client offered it.
for _, compression := range hs.clientHello.compressionMethods {
if compression == compressionNone {
foundCompression = true
break
}
}
if !foundCompression {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: client does not support uncompressed connections")
}
hs.hello.random = make([]byte, 32)
serverRandom := hs.hello.random
// Downgrade protection canaries. See RFC 8446, Section 4.1.3.
maxVers := c.config.maxSupportedVersion(roleServer)
if maxVers >= VersionTLS12 && c.vers < maxVers || testingOnlyForceDowngradeCanary {
if c.vers == VersionTLS12 {
copy(serverRandom[24:], downgradeCanaryTLS12)
} else {
copy(serverRandom[24:], downgradeCanaryTLS11)
}
serverRandom = serverRandom[:24]
}
_, err := io.ReadFull(c.config.rand(), serverRandom)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
if len(hs.clientHello.secureRenegotiation) != 0 {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: initial handshake had non-empty renegotiation extension")
}
hs.hello.extendedMasterSecret = hs.clientHello.extendedMasterSecret
hs.hello.secureRenegotiationSupported = hs.clientHello.secureRenegotiationSupported
hs.hello.compressionMethod = compressionNone
if len(hs.clientHello.serverName) > 0 {
c.serverName = hs.clientHello.serverName
}
selectedProto, err := negotiateALPN(c.config.NextProtos, hs.clientHello.alpnProtocols, false)
if err != nil {
c.sendAlert(alertNoApplicationProtocol)
return err
}
hs.hello.alpnProtocol = selectedProto
c.clientProtocol = selectedProto
hs.cert, err = c.config.getCertificate(clientHelloInfo(hs.ctx, c, hs.clientHello))
if err != nil {
if err == errNoCertificates {
c.sendAlert(alertUnrecognizedName)
} else {
c.sendAlert(alertInternalError)
}
return err
}
if hs.clientHello.scts {
hs.hello.scts = hs.cert.SignedCertificateTimestamps
}
hs.ecdheOk = supportsECDHE(c.config, c.vers, hs.clientHello.supportedCurves, hs.clientHello.supportedPoints)
if hs.ecdheOk && len(hs.clientHello.supportedPoints) > 0 {
// Although omitting the ec_point_formats extension is permitted, some
// old OpenSSL version will refuse to handshake if not present.
//
// Per RFC 4492, section 5.1.2, implementations MUST support the
// uncompressed point format. See golang.org/issue/31943.
hs.hello.supportedPoints = []uint8{pointFormatUncompressed}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Signer); ok {
switch priv.Public().(type) {
case *ecdsa.PublicKey:
hs.ecSignOk = true
case ed25519.PublicKey:
hs.ecSignOk = true
case *rsa.PublicKey:
hs.rsaSignOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported signing key type (%T)", priv.Public())
}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Decrypter); ok {
switch priv.Public().(type) {
case *rsa.PublicKey:
hs.rsaDecryptOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported decryption key type (%T)", priv.Public())
}
}
return nil
}
// negotiateALPN picks a shared ALPN protocol that both sides support in server
// preference order. If ALPN is not configured or the peer doesn't support it,
// it returns "" and no error.
func negotiateALPN(serverProtos, clientProtos []string, quic bool) (string, error) {
if len(serverProtos) == 0 || len(clientProtos) == 0 {
if quic && len(serverProtos) != 0 {
// RFC 9001, Section 8.1
return "", fmt.Errorf("tls: client did not request an application protocol")
}
return "", nil
}
var http11fallback bool
for _, s := range serverProtos {
for _, c := range clientProtos {
if s == c {
return s, nil
}
if s == "h2" && c == "http/1.1" {
http11fallback = true
}
}
}
// As a special case, let http/1.1 clients connect to h2 servers as if they
// didn't support ALPN. We used not to enforce protocol overlap, so over
// time a number of HTTP servers were configured with only "h2", but
// expected to accept connections from "http/1.1" clients. See Issue 46310.
if http11fallback {
return "", nil
}
return "", fmt.Errorf("tls: client requested unsupported application protocols (%s)", clientProtos)
}
// supportsECDHE returns whether ECDHE key exchanges can be used with this
// pre-TLS 1.3 client.
func supportsECDHE(c *Config, version uint16, supportedCurves []CurveID, supportedPoints []uint8) bool {
supportsCurve := false
for _, curve := range supportedCurves {
if c.supportsCurve(version, curve) {
supportsCurve = true
break
}
}
supportsPointFormat := false
for _, pointFormat := range supportedPoints {
if pointFormat == pointFormatUncompressed {
supportsPointFormat = true
break
}
}
// Per RFC 8422, Section 5.1.2, if the Supported Point Formats extension is
// missing, uncompressed points are supported. If supportedPoints is empty,
// the extension must be missing, as an empty extension body is rejected by
// the parser. See https://go.dev/issue/49126.
if len(supportedPoints) == 0 {
supportsPointFormat = true
}
return supportsCurve && supportsPointFormat
}
func (hs *serverHandshakeState) pickCipherSuite() error {
c := hs.c
preferenceOrder := cipherSuitesPreferenceOrder
if !hasAESGCMHardwareSupport || !aesgcmPreferred(hs.clientHello.cipherSuites) {
preferenceOrder = cipherSuitesPreferenceOrderNoAES
}
configCipherSuites := c.config.cipherSuites()
preferenceList := make([]uint16, 0, len(configCipherSuites))
for _, suiteID := range preferenceOrder {
for _, id := range configCipherSuites {
if id == suiteID {
preferenceList = append(preferenceList, id)
break
}
}
}
hs.suite = selectCipherSuite(preferenceList, hs.clientHello.cipherSuites, hs.cipherSuiteOk)
if hs.suite == nil {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: no cipher suite supported by both client and server")
}
c.cipherSuite = hs.suite.id
for _, id := range hs.clientHello.cipherSuites {
if id == TLS_FALLBACK_SCSV {
// The client is doing a fallback connection. See RFC 7507.
if hs.clientHello.vers < c.config.maxSupportedVersion(roleServer) {
c.sendAlert(alertInappropriateFallback)
return errors.New("tls: client using inappropriate protocol fallback")
}
break
}
}
return nil
}
func (hs *serverHandshakeState) cipherSuiteOk(c *cipherSuite) bool {
if c.flags&suiteECDHE != 0 {
if !hs.ecdheOk {
return false
}
if c.flags&suiteECSign != 0 {
if !hs.ecSignOk {
return false
}
} else if !hs.rsaSignOk {
return false
}
} else if !hs.rsaDecryptOk {
return false
}
if hs.c.vers < VersionTLS12 && c.flags&suiteTLS12 != 0 {
return false
}
return true
}
// checkForResumption reports whether we should perform resumption on this connection.
func (hs *serverHandshakeState) checkForResumption() error {
c := hs.c
if c.config.SessionTicketsDisabled {
return nil
}
var sessionState *SessionState
if c.config.UnwrapSession != nil {
ss, err := c.config.UnwrapSession(hs.clientHello.sessionTicket, c.connectionStateLocked())
if err != nil {
return err
}
if ss == nil {
return nil
}
sessionState = ss
} else {
plaintext := c.config.decryptTicket(hs.clientHello.sessionTicket, c.ticketKeys)
if plaintext == nil {
return nil
}
ss, err := ParseSessionState(plaintext)
if err != nil {
return nil
}
sessionState = ss
}
// TLS 1.2 tickets don't natively have a lifetime, but we want to avoid
// re-wrapping the same master secret in different tickets over and over for
// too long, weakening forward secrecy.
createdAt := time.Unix(int64(sessionState.createdAt), 0)
if c.config.time().Sub(createdAt) > maxSessionTicketLifetime {
return nil
}
// Never resume a session for a different TLS version.
if c.vers != sessionState.version {
return nil
}
cipherSuiteOk := false
// Check that the client is still offering the ciphersuite in the session.
for _, id := range hs.clientHello.cipherSuites {
if id == sessionState.cipherSuite {
cipherSuiteOk = true
break
}
}
if !cipherSuiteOk {
return nil
}
// Check that we also support the ciphersuite from the session.
suite := selectCipherSuite([]uint16{sessionState.cipherSuite},
c.config.cipherSuites(), hs.cipherSuiteOk)
if suite == nil {
return nil
}
sessionHasClientCerts := len(sessionState.peerCertificates) != 0
needClientCerts := requiresClientCert(c.config.ClientAuth)
if needClientCerts && !sessionHasClientCerts {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth == NoClientCert {
return nil
}
if sessionHasClientCerts && c.config.time().After(sessionState.peerCertificates[0].NotAfter) {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth >= VerifyClientCertIfGiven &&
len(sessionState.verifiedChains) == 0 {
return nil
}
// RFC 7627, Section 5.3
if !sessionState.extMasterSecret && hs.clientHello.extendedMasterSecret {
return nil
}
if sessionState.extMasterSecret && !hs.clientHello.extendedMasterSecret {
// Aborting is somewhat harsh, but it's a MUST and it would indicate a
// weird downgrade in client capabilities.
return errors.New("tls: session supported extended_master_secret but client does not")
}
c.peerCertificates = sessionState.peerCertificates
c.ocspResponse = sessionState.ocspResponse
c.scts = sessionState.scts
c.verifiedChains = sessionState.verifiedChains
c.extMasterSecret = sessionState.extMasterSecret
hs.sessionState = sessionState
hs.suite = suite
c.didResume = true
return nil
}
func (hs *serverHandshakeState) doResumeHandshake() error {
c := hs.c
hs.hello.cipherSuite = hs.suite.id
c.cipherSuite = hs.suite.id
// We echo the client's session ID in the ServerHello to let it know
// that we're doing a resumption.
hs.hello.sessionId = hs.clientHello.sessionId
// We always send a new session ticket, even if it wraps the same master
// secret and it's potentially encrypted with the same key, to help the
// client avoid cross-connection tracking from a network observer.
hs.hello.ticketSupported = true
hs.finishedHash = newFinishedHash(c.vers, hs.suite)
hs.finishedHash.discardHandshakeBuffer()
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
hs.masterSecret = hs.sessionState.secret
return nil
}
func (hs *serverHandshakeState) doFullHandshake() error {
c := hs.c
if hs.clientHello.ocspStapling && len(hs.cert.OCSPStaple) > 0 {
hs.hello.ocspStapling = true
}
hs.hello.ticketSupported = hs.clientHello.ticketSupported && !c.config.SessionTicketsDisabled
hs.hello.cipherSuite = hs.suite.id
hs.finishedHash = newFinishedHash(hs.c.vers, hs.suite)
if c.config.ClientAuth == NoClientCert {
// No need to keep a full record of the handshake if client
// certificates won't be used.
hs.finishedHash.discardHandshakeBuffer()
}
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
certMsg := new(certificateMsg)
certMsg.certificates = hs.cert.Certificate
if _, err := hs.c.writeHandshakeRecord(certMsg, &hs.finishedHash); err != nil {
return err
}
if hs.hello.ocspStapling {
certStatus := new(certificateStatusMsg)
certStatus.response = hs.cert.OCSPStaple
if _, err := hs.c.writeHandshakeRecord(certStatus, &hs.finishedHash); err != nil {
return err
}
}
keyAgreement := hs.suite.ka(c.vers)
skx, err := keyAgreement.generateServerKeyExchange(c.config, hs.cert, hs.clientHello, hs.hello)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
}
if skx != nil {
if len(skx.key) >= 3 && skx.key[0] == 3 /* named curve */ {
c.curveID = CurveID(byteorder.BeUint16(skx.key[1:]))
}
if _, err := hs.c.writeHandshakeRecord(skx, &hs.finishedHash); err != nil {
return err
}
}
var certReq *certificateRequestMsg
if c.config.ClientAuth >= RequestClientCert {
// Request a client certificate
certReq = new(certificateRequestMsg)
certReq.certificateTypes = []byte{
byte(certTypeRSASign),
byte(certTypeECDSASign),
}
if c.vers >= VersionTLS12 {
certReq.hasSignatureAlgorithm = true
certReq.supportedSignatureAlgorithms = supportedSignatureAlgorithms()
}
// An empty list of certificateAuthorities signals to
// the client that it may send any certificate in response
// to our request. When we know the CAs we trust, then
// we can send them down, so that the client can choose
// an appropriate certificate to give to us.
if c.config.ClientCAs != nil {
certReq.certificateAuthorities = c.config.ClientCAs.Subjects()
}
if _, err := hs.c.writeHandshakeRecord(certReq, &hs.finishedHash); err != nil {
return err
}
}
helloDone := new(serverHelloDoneMsg)
if _, err := hs.c.writeHandshakeRecord(helloDone, &hs.finishedHash); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
var pub crypto.PublicKey // public key for client auth, if any
msg, err := c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
// If we requested a client certificate, then the client must send a
// certificate message, even if it's empty.
if c.config.ClientAuth >= RequestClientCert {
certMsg, ok := msg.(*certificateMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certMsg, msg)
}
if err := c.processCertsFromClient(Certificate{
Certificate: certMsg.certificates,
}); err != nil {
return err
}
if len(certMsg.certificates) != 0 {
pub = c.peerCertificates[0].PublicKey
}
msg, err = c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
// Get client key exchange
ckx, ok := msg.(*clientKeyExchangeMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(ckx, msg)
}
preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert, ckx, c.vers)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
}
if hs.hello.extendedMasterSecret {
c.extMasterSecret = true
hs.masterSecret = extMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.finishedHash.Sum())
} else {
hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.clientHello.random, hs.hello.random)
}
if err := c.config.writeKeyLog(keyLogLabelTLS12, hs.clientHello.random, hs.masterSecret); err != nil {
c.sendAlert(alertInternalError)
return err
}
// If we received a client cert in response to our certificate request message,
// the client will send us a certificateVerifyMsg immediately after the
// clientKeyExchangeMsg. This message is a digest of all preceding
// handshake-layer messages that is signed using the private key corresponding
// to the client's certificate. This allows us to verify that the client is in
// possession of the private key of the certificate.
if len(c.peerCertificates) > 0 {
// certificateVerifyMsg is included in the transcript, but not until
// after we verify the handshake signature, since the state before
// this message was sent is used.
msg, err = c.readHandshake(nil)
if err != nil {
return err
}
certVerify, ok := msg.(*certificateVerifyMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certVerify, msg)
}
var sigType uint8
var sigHash crypto.Hash
if c.vers >= VersionTLS12 {
if !isSupportedSignatureAlgorithm(certVerify.signatureAlgorithm, certReq.supportedSignatureAlgorithms) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: client certificate used with invalid signature algorithm")
}
sigType, sigHash, err = typeAndHashFromSignatureScheme(certVerify.signatureAlgorithm)
if err != nil {
return c.sendAlert(alertInternalError)
}
} else {
sigType, sigHash, err = legacyTypeAndHashFromPublicKey(pub)
if err != nil {
c.sendAlert(alertIllegalParameter)
return err
}
}
signed := hs.finishedHash.hashForClientCertificate(sigType, sigHash)
if err := verifyHandshakeSignature(sigType, pub, sigHash, signed, certVerify.signature); err != nil {
c.sendAlert(alertDecryptError)
return errors.New("tls: invalid signature by the client certificate: " + err.Error())
}
if err := transcriptMsg(certVerify, &hs.finishedHash); err != nil {
return err
}
}
hs.finishedHash.discardHandshakeBuffer()
return nil
}
func (hs *serverHandshakeState) establishKeys() error {
c := hs.c
clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV := keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
var clientCipher, serverCipher any
var clientHash, serverHash hash.Hash
if hs.suite.aead == nil {
clientCipher = hs.suite.cipher(clientKey, clientIV, true /* for reading */)
clientHash = hs.suite.mac(clientMAC)
serverCipher = hs.suite.cipher(serverKey, serverIV, false /* not for reading */)
serverHash = hs.suite.mac(serverMAC)
} else {
clientCipher = hs.suite.aead(clientKey, clientIV)
serverCipher = hs.suite.aead(serverKey, serverIV)
}
c.in.prepareCipherSpec(c.vers, clientCipher, clientHash)
c.out.prepareCipherSpec(c.vers, serverCipher, serverHash)
return nil
}
func (hs *serverHandshakeState) readFinished(out []byte) error {
c := hs.c
if err := c.readChangeCipherSpec(); err != nil {
return err
}
// finishedMsg is included in the transcript, but not until after we
// check the client version, since the state before this message was
// sent is used during verification.
msg, err := c.readHandshake(nil)
if err != nil {
return err
}
clientFinished, ok := msg.(*finishedMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(clientFinished, msg)
}
verify := hs.finishedHash.clientSum(hs.masterSecret)
if len(verify) != len(clientFinished.verifyData) ||
subtle.ConstantTimeCompare(verify, clientFinished.verifyData) != 1 {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: client's Finished message is incorrect")
}
if err := transcriptMsg(clientFinished, &hs.finishedHash); err != nil {
return err
}
copy(out, verify)
return nil
}
func (hs *serverHandshakeState) sendSessionTicket() error {
if !hs.hello.ticketSupported {
return nil
}
c := hs.c
m := new(newSessionTicketMsg)
state := c.sessionState()
state.secret = hs.masterSecret
if hs.sessionState != nil {
// If this is re-wrapping an old key, then keep
// the original time it was created.
state.createdAt = hs.sessionState.createdAt
}
if c.config.WrapSession != nil {
var err error
m.ticket, err = c.config.WrapSession(c.connectionStateLocked(), state)
if err != nil {
return err
}
} else {
stateBytes, err := state.Bytes()
if err != nil {
return err
}
m.ticket, err = c.config.encryptTicket(stateBytes, c.ticketKeys)
if err != nil {
return err
}
}
if _, err := hs.c.writeHandshakeRecord(m, &hs.finishedHash); err != nil {
return err
}
return nil
}
func (hs *serverHandshakeState) sendFinished(out []byte) error {
c := hs.c
if err := c.writeChangeCipherRecord(); err != nil {
return err
}
finished := new(finishedMsg)
finished.verifyData = hs.finishedHash.serverSum(hs.masterSecret)
if _, err := hs.c.writeHandshakeRecord(finished, &hs.finishedHash); err != nil {
return err
}
copy(out, finished.verifyData)
return nil
}
// processCertsFromClient takes a chain of client certificates either from a
// Certificates message and verifies them.
func (c *Conn) processCertsFromClient(certificate Certificate) error {
certificates := certificate.Certificate
certs := make([]*x509.Certificate, len(certificates))
var err error
for i, asn1Data := range certificates {
if certs[i], err = x509.ParseCertificate(asn1Data); err != nil {
c.sendAlert(alertBadCertificate)
return errors.New("tls: failed to parse client certificate: " + err.Error())
}
if certs[i].PublicKeyAlgorithm == x509.RSA {
n := certs[i].PublicKey.(*rsa.PublicKey).N.BitLen()
if max, ok := checkKeySize(n); !ok {
c.sendAlert(alertBadCertificate)
return fmt.Errorf("tls: client sent certificate containing RSA key larger than %d bits", max)
}
}
}
if len(certs) == 0 && requiresClientCert(c.config.ClientAuth) {
if c.vers == VersionTLS13 {
c.sendAlert(alertCertificateRequired)
} else {
c.sendAlert(alertBadCertificate)
}
return errors.New("tls: client didn't provide a certificate")
}
if c.config.ClientAuth >= VerifyClientCertIfGiven && len(certs) > 0 {
opts := x509.VerifyOptions{
Roots: c.config.ClientCAs,
CurrentTime: c.config.time(),
Intermediates: x509.NewCertPool(),
KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
}
for _, cert := range certs[1:] {
opts.Intermediates.AddCert(cert)
}
chains, err := certs[0].Verify(opts)
if err != nil {
var errCertificateInvalid x509.CertificateInvalidError
if errors.As(err, &x509.UnknownAuthorityError{}) {
c.sendAlert(alertUnknownCA)
} else if errors.As(err, &errCertificateInvalid) && errCertificateInvalid.Reason == x509.Expired {
c.sendAlert(alertCertificateExpired)
} else {
c.sendAlert(alertBadCertificate)
}
return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
}
c.verifiedChains = chains
}
c.peerCertificates = certs
c.ocspResponse = certificate.OCSPStaple
c.scts = certificate.SignedCertificateTimestamps
if len(certs) > 0 {
switch certs[0].PublicKey.(type) {
case *ecdsa.PublicKey, *rsa.PublicKey, ed25519.PublicKey:
default:
c.sendAlert(alertUnsupportedCertificate)
return fmt.Errorf("tls: client certificate contains an unsupported public key of type %T", certs[0].PublicKey)
}
}
if c.config.VerifyPeerCertificate != nil {
if err := c.config.VerifyPeerCertificate(certificates, c.verifiedChains); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
return nil
}
func clientHelloInfo(ctx context.Context, c *Conn, clientHello *clientHelloMsg) *ClientHelloInfo {
supportedVersions := clientHello.supportedVersions
if len(clientHello.supportedVersions) == 0 {
supportedVersions = supportedVersionsFromMax(clientHello.vers)
}
return &ClientHelloInfo{
CipherSuites: clientHello.cipherSuites,
ServerName: clientHello.serverName,
SupportedCurves: clientHello.supportedCurves,
SupportedPoints: clientHello.supportedPoints,
SignatureSchemes: clientHello.supportedSignatureAlgorithms,
SupportedProtos: clientHello.alpnProtocols,
SupportedVersions: supportedVersions,
Conn: c.conn,
config: c.config,
ctx: ctx,
}
}

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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto"
"crypto/ecdh"
"crypto/md5"
"crypto/rsa"
"crypto/sha1"
"crypto/x509"
"errors"
"fmt"
"io"
)
// A keyAgreement implements the client and server side of a TLS 1.0–1.2 key
// agreement protocol by generating and processing key exchange messages.
type keyAgreement interface {
// On the server side, the first two methods are called in order.
// In the case that the key agreement protocol doesn't use a
// ServerKeyExchange message, generateServerKeyExchange can return nil,
// nil.
generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
// On the client side, the next two methods are called in order.
// This method may not be called if the server doesn't send a
// ServerKeyExchange message.
processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error
generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
}
var (
errClientKeyExchange = errors.New("tls: invalid ClientKeyExchange message")
errServerKeyExchange = errors.New("tls: invalid ServerKeyExchange message")
)
// rsaKeyAgreement implements the standard TLS key agreement where the client
// encrypts the pre-master secret to the server's public key.
type rsaKeyAgreement struct{}
func (ka rsaKeyAgreement) generateServerKeyExchange(config *Config, cert *Certificate, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
return nil, nil
}
func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, cert *Certificate, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
if len(ckx.ciphertext) < 2 {
return nil, errClientKeyExchange
}
ciphertextLen := int(ckx.ciphertext[0])<<8 | int(ckx.ciphertext[1])
if ciphertextLen != len(ckx.ciphertext)-2 {
return nil, errClientKeyExchange
}
ciphertext := ckx.ciphertext[2:]
priv, ok := cert.PrivateKey.(crypto.Decrypter)
if !ok {
return nil, errors.New("tls: certificate private key does not implement crypto.Decrypter")
}
// Perform constant time RSA PKCS #1 v1.5 decryption
preMasterSecret, err := priv.Decrypt(config.rand(), ciphertext, &rsa.PKCS1v15DecryptOptions{SessionKeyLen: 48})
if err != nil {
return nil, err
}
// We don't check the version number in the premaster secret. For one,
// by checking it, we would leak information about the validity of the
// encrypted pre-master secret. Secondly, it provides only a small
// benefit against a downgrade attack and some implementations send the
// wrong version anyway. See the discussion at the end of section
// 7.4.7.1 of RFC 4346.
return preMasterSecret, nil
}
func (ka rsaKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) error {
return errors.New("tls: unexpected ServerKeyExchange")
}
func (ka rsaKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error) {
preMasterSecret := make([]byte, 48)
preMasterSecret[0] = byte(clientHello.vers >> 8)
preMasterSecret[1] = byte(clientHello.vers)
_, err := io.ReadFull(config.rand(), preMasterSecret[2:])
if err != nil {
return nil, nil, err
}
rsaKey, ok := cert.PublicKey.(*rsa.PublicKey)
if !ok {
return nil, nil, errors.New("tls: server certificate contains incorrect key type for selected ciphersuite")
}
encrypted, err := rsa.EncryptPKCS1v15(config.rand(), rsaKey, preMasterSecret)
if err != nil {
return nil, nil, err
}
ckx := new(clientKeyExchangeMsg)
ckx.ciphertext = make([]byte, len(encrypted)+2)
ckx.ciphertext[0] = byte(len(encrypted) >> 8)
ckx.ciphertext[1] = byte(len(encrypted))
copy(ckx.ciphertext[2:], encrypted)
return preMasterSecret, ckx, nil
}
// sha1Hash calculates a SHA1 hash over the given byte slices.
func sha1Hash(slices [][]byte) []byte {
hsha1 := sha1.New()
for _, slice := range slices {
hsha1.Write(slice)
}
return hsha1.Sum(nil)
}
// md5SHA1Hash implements TLS 1.0's hybrid hash function which consists of the
// concatenation of an MD5 and SHA1 hash.
func md5SHA1Hash(slices [][]byte) []byte {
md5sha1 := make([]byte, md5.Size+sha1.Size)
hmd5 := md5.New()
for _, slice := range slices {
hmd5.Write(slice)
}
copy(md5sha1, hmd5.Sum(nil))
copy(md5sha1[md5.Size:], sha1Hash(slices))
return md5sha1
}
// hashForServerKeyExchange hashes the given slices and returns their digest
// using the given hash function (for TLS 1.2) or using a default based on
// the sigType (for earlier TLS versions). For Ed25519 signatures, which don't
// do pre-hashing, it returns the concatenation of the slices.
func hashForServerKeyExchange(sigType uint8, hashFunc crypto.Hash, version uint16, slices ...[]byte) []byte {
if sigType == signatureEd25519 {
var signed []byte
for _, slice := range slices {
signed = append(signed, slice...)
}
return signed
}
if version >= VersionTLS12 {
h := hashFunc.New()
for _, slice := range slices {
h.Write(slice)
}
digest := h.Sum(nil)
return digest
}
if sigType == signatureECDSA {
return sha1Hash(slices)
}
return md5SHA1Hash(slices)
}
// ecdheKeyAgreement implements a TLS key agreement where the server
// generates an ephemeral EC public/private key pair and signs it. The
// pre-master secret is then calculated using ECDH. The signature may
// be ECDSA, Ed25519 or RSA.
type ecdheKeyAgreement struct {
version uint16
isRSA bool
key *ecdh.PrivateKey
// ckx and preMasterSecret are generated in processServerKeyExchange
// and returned in generateClientKeyExchange.
ckx *clientKeyExchangeMsg
preMasterSecret []byte
}
func (ka *ecdheKeyAgreement) generateServerKeyExchange(config *Config, cert *Certificate, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
var curveID CurveID
for _, c := range clientHello.supportedCurves {
if config.supportsCurve(ka.version, c) {
curveID = c
break
}
}
if curveID == 0 {
return nil, errors.New("tls: no supported elliptic curves offered")
}
if _, ok := curveForCurveID(curveID); !ok {
return nil, errors.New("tls: CurvePreferences includes unsupported curve")
}
key, err := generateECDHEKey(config.rand(), curveID)
if err != nil {
return nil, err
}
ka.key = key
// See RFC 4492, Section 5.4.
ecdhePublic := key.PublicKey().Bytes()
serverECDHEParams := make([]byte, 1+2+1+len(ecdhePublic))
serverECDHEParams[0] = 3 // named curve
serverECDHEParams[1] = byte(curveID >> 8)
serverECDHEParams[2] = byte(curveID)
serverECDHEParams[3] = byte(len(ecdhePublic))
copy(serverECDHEParams[4:], ecdhePublic)
priv, ok := cert.PrivateKey.(crypto.Signer)
if !ok {
return nil, fmt.Errorf("tls: certificate private key of type %T does not implement crypto.Signer", cert.PrivateKey)
}
var signatureAlgorithm SignatureScheme
var sigType uint8
var sigHash crypto.Hash
if ka.version >= VersionTLS12 {
signatureAlgorithm, err = selectSignatureScheme(ka.version, cert, clientHello.supportedSignatureAlgorithms)
if err != nil {
return nil, err
}
sigType, sigHash, err = typeAndHashFromSignatureScheme(signatureAlgorithm)
if err != nil {
return nil, err
}
} else {
sigType, sigHash, err = legacyTypeAndHashFromPublicKey(priv.Public())
if err != nil {
return nil, err
}
}
if (sigType == signaturePKCS1v15 || sigType == signatureRSAPSS) != ka.isRSA {
return nil, errors.New("tls: certificate cannot be used with the selected cipher suite")
}
signed := hashForServerKeyExchange(sigType, sigHash, ka.version, clientHello.random, hello.random, serverECDHEParams)
signOpts := crypto.SignerOpts(sigHash)
if sigType == signatureRSAPSS {
signOpts = &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash, Hash: sigHash}
}
sig, err := priv.Sign(config.rand(), signed, signOpts)
if err != nil {
return nil, errors.New("tls: failed to sign ECDHE parameters: " + err.Error())
}
skx := new(serverKeyExchangeMsg)
sigAndHashLen := 0
if ka.version >= VersionTLS12 {
sigAndHashLen = 2
}
skx.key = make([]byte, len(serverECDHEParams)+sigAndHashLen+2+len(sig))
copy(skx.key, serverECDHEParams)
k := skx.key[len(serverECDHEParams):]
if ka.version >= VersionTLS12 {
k[0] = byte(signatureAlgorithm >> 8)
k[1] = byte(signatureAlgorithm)
k = k[2:]
}
k[0] = byte(len(sig) >> 8)
k[1] = byte(len(sig))
copy(k[2:], sig)
return skx, nil
}
func (ka *ecdheKeyAgreement) processClientKeyExchange(config *Config, cert *Certificate, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
if len(ckx.ciphertext) == 0 || int(ckx.ciphertext[0]) != len(ckx.ciphertext)-1 {
return nil, errClientKeyExchange
}
peerKey, err := ka.key.Curve().NewPublicKey(ckx.ciphertext[1:])
if err != nil {
return nil, errClientKeyExchange
}
preMasterSecret, err := ka.key.ECDH(peerKey)
if err != nil {
return nil, errClientKeyExchange
}
return preMasterSecret, nil
}
func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) error {
if len(skx.key) < 4 {
return errServerKeyExchange
}
if skx.key[0] != 3 { // named curve
return errors.New("tls: server selected unsupported curve")
}
curveID := CurveID(skx.key[1])<<8 | CurveID(skx.key[2])
publicLen := int(skx.key[3])
if publicLen+4 > len(skx.key) {
return errServerKeyExchange
}
serverECDHEParams := skx.key[:4+publicLen]
publicKey := serverECDHEParams[4:]
sig := skx.key[4+publicLen:]
if len(sig) < 2 {
return errServerKeyExchange
}
if _, ok := curveForCurveID(curveID); !ok {
return errors.New("tls: server selected unsupported curve")
}
key, err := generateECDHEKey(config.rand(), curveID)
if err != nil {
return err
}
ka.key = key
peerKey, err := key.Curve().NewPublicKey(publicKey)
if err != nil {
return errServerKeyExchange
}
ka.preMasterSecret, err = key.ECDH(peerKey)
if err != nil {
return errServerKeyExchange
}
ourPublicKey := key.PublicKey().Bytes()
ka.ckx = new(clientKeyExchangeMsg)
ka.ckx.ciphertext = make([]byte, 1+len(ourPublicKey))
ka.ckx.ciphertext[0] = byte(len(ourPublicKey))
copy(ka.ckx.ciphertext[1:], ourPublicKey)
var sigType uint8
var sigHash crypto.Hash
if ka.version >= VersionTLS12 {
signatureAlgorithm := SignatureScheme(sig[0])<<8 | SignatureScheme(sig[1])
sig = sig[2:]
if len(sig) < 2 {
return errServerKeyExchange
}
if !isSupportedSignatureAlgorithm(signatureAlgorithm, clientHello.supportedSignatureAlgorithms) {
return errors.New("tls: certificate used with invalid signature algorithm")
}
sigType, sigHash, err = typeAndHashFromSignatureScheme(signatureAlgorithm)
if err != nil {
return err
}
} else {
sigType, sigHash, err = legacyTypeAndHashFromPublicKey(cert.PublicKey)
if err != nil {
return err
}
}
if (sigType == signaturePKCS1v15 || sigType == signatureRSAPSS) != ka.isRSA {
return errServerKeyExchange
}
sigLen := int(sig[0])<<8 | int(sig[1])
if sigLen+2 != len(sig) {
return errServerKeyExchange
}
sig = sig[2:]
signed := hashForServerKeyExchange(sigType, sigHash, ka.version, clientHello.random, serverHello.random, serverECDHEParams)
if err := verifyHandshakeSignature(sigType, cert.PublicKey, sigHash, signed, sig); err != nil {
return errors.New("tls: invalid signature by the server certificate: " + err.Error())
}
return nil
}
func (ka *ecdheKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error) {
if ka.ckx == nil {
return nil, nil, errors.New("tls: missing ServerKeyExchange message")
}
return ka.preMasterSecret, ka.ckx, nil
}

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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto/ecdh"
"crypto/hmac"
"errors"
"fmt"
"hash"
"io"
"github.com/sagernet/sing-shadowtls/internal/mlkem768"
"golang.org/x/crypto/cryptobyte"
"golang.org/x/crypto/hkdf"
"golang.org/x/crypto/sha3"
)
// This file contains the functions necessary to compute the TLS 1.3 key
// schedule. See RFC 8446, Section 7.
const (
resumptionBinderLabel = "res binder"
clientEarlyTrafficLabel = "c e traffic"
clientHandshakeTrafficLabel = "c hs traffic"
serverHandshakeTrafficLabel = "s hs traffic"
clientApplicationTrafficLabel = "c ap traffic"
serverApplicationTrafficLabel = "s ap traffic"
exporterLabel = "exp master"
resumptionLabel = "res master"
trafficUpdateLabel = "traffic upd"
)
// expandLabel implements HKDF-Expand-Label from RFC 8446, Section 7.1.
func (c *cipherSuiteTLS13) expandLabel(secret []byte, label string, context []byte, length int) []byte {
var hkdfLabel cryptobyte.Builder
hkdfLabel.AddUint16(uint16(length))
hkdfLabel.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes([]byte("tls13 "))
b.AddBytes([]byte(label))
})
hkdfLabel.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes(context)
})
hkdfLabelBytes, err := hkdfLabel.Bytes()
if err != nil {
// Rather than calling BytesOrPanic, we explicitly handle this error, in
// order to provide a reasonable error message. It should be basically
// impossible for this to panic, and routing errors back through the
// tree rooted in this function is quite painful. The labels are fixed
// size, and the context is either a fixed-length computed hash, or
// parsed from a field which has the same length limitation. As such, an
// error here is likely to only be caused during development.
//
// NOTE: another reasonable approach here might be to return a
// randomized slice if we encounter an error, which would break the
// connection, but avoid panicking. This would perhaps be safer but
// significantly more confusing to users.
panic(fmt.Errorf("failed to construct HKDF label: %s", err))
}
out := make([]byte, length)
n, err := hkdf.Expand(c.hash.New, secret, hkdfLabelBytes).Read(out)
if err != nil || n != length {
panic("tls: HKDF-Expand-Label invocation failed unexpectedly")
}
return out
}
// deriveSecret implements Derive-Secret from RFC 8446, Section 7.1.
func (c *cipherSuiteTLS13) deriveSecret(secret []byte, label string, transcript hash.Hash) []byte {
if transcript == nil {
transcript = c.hash.New()
}
return c.expandLabel(secret, label, transcript.Sum(nil), c.hash.Size())
}
// extract implements HKDF-Extract with the cipher suite hash.
func (c *cipherSuiteTLS13) extract(newSecret, currentSecret []byte) []byte {
if newSecret == nil {
newSecret = make([]byte, c.hash.Size())
}
return hkdf.Extract(c.hash.New, newSecret, currentSecret)
}
// nextTrafficSecret generates the next traffic secret, given the current one,
// according to RFC 8446, Section 7.2.
func (c *cipherSuiteTLS13) nextTrafficSecret(trafficSecret []byte) []byte {
return c.expandLabel(trafficSecret, trafficUpdateLabel, nil, c.hash.Size())
}
// trafficKey generates traffic keys according to RFC 8446, Section 7.3.
func (c *cipherSuiteTLS13) trafficKey(trafficSecret []byte) (key, iv []byte) {
key = c.expandLabel(trafficSecret, "key", nil, c.keyLen)
iv = c.expandLabel(trafficSecret, "iv", nil, aeadNonceLength)
return
}
// finishedHash generates the Finished verify_data or PskBinderEntry according
// to RFC 8446, Section 4.4.4. See sections 4.4 and 4.2.11.2 for the baseKey
// selection.
func (c *cipherSuiteTLS13) finishedHash(baseKey []byte, transcript hash.Hash) []byte {
finishedKey := c.expandLabel(baseKey, "finished", nil, c.hash.Size())
verifyData := hmac.New(c.hash.New, finishedKey)
verifyData.Write(transcript.Sum(nil))
return verifyData.Sum(nil)
}
// exportKeyingMaterial implements RFC5705 exporters for TLS 1.3 according to
// RFC 8446, Section 7.5.
func (c *cipherSuiteTLS13) exportKeyingMaterial(masterSecret []byte, transcript hash.Hash) func(string, []byte, int) ([]byte, error) {
expMasterSecret := c.deriveSecret(masterSecret, exporterLabel, transcript)
return func(label string, context []byte, length int) ([]byte, error) {
secret := c.deriveSecret(expMasterSecret, label, nil)
h := c.hash.New()
h.Write(context)
return c.expandLabel(secret, "exporter", h.Sum(nil), length), nil
}
}
type keySharePrivateKeys struct {
curveID CurveID
ecdhe *ecdh.PrivateKey
kyber *mlkem768.DecapsulationKey
}
// kyberDecapsulate implements decapsulation according to Kyber Round 3.
func kyberDecapsulate(dk *mlkem768.DecapsulationKey, c []byte) ([]byte, error) {
K, err := mlkem768.Decapsulate(dk, c)
if err != nil {
return nil, err
}
return kyberSharedSecret(K, c), nil
}
// kyberEncapsulate implements encapsulation according to Kyber Round 3.
func kyberEncapsulate(ek []byte) (c, ss []byte, err error) {
c, ss, err = mlkem768.Encapsulate(ek)
if err != nil {
return nil, nil, err
}
return c, kyberSharedSecret(ss, c), nil
}
func kyberSharedSecret(K, c []byte) []byte {
// Package mlkem768 implements ML-KEM, which compared to Kyber removed a
// final hashing step. Compute SHAKE-256(K || SHA3-256(c), 32) to match Kyber.
// See https://words.filippo.io/mlkem768/#bonus-track-using-a-ml-kem-implementation-as-kyber-v3.
h := sha3.NewShake256()
h.Write(K)
ch := sha3.Sum256(c)
h.Write(ch[:])
out := make([]byte, 32)
h.Read(out)
return out
}
const x25519PublicKeySize = 32
// generateECDHEKey returns a PrivateKey that implements Diffie-Hellman
// according to RFC 8446, Section 4.2.8.2.
func generateECDHEKey(rand io.Reader, curveID CurveID) (*ecdh.PrivateKey, error) {
curve, ok := curveForCurveID(curveID)
if !ok {
return nil, errors.New("tls: internal error: unsupported curve")
}
return curve.GenerateKey(rand)
}
func curveForCurveID(id CurveID) (ecdh.Curve, bool) {
switch id {
case X25519:
return ecdh.X25519(), true
case CurveP256:
return ecdh.P256(), true
case CurveP384:
return ecdh.P384(), true
case CurveP521:
return ecdh.P521(), true
default:
return nil, false
}
}
func curveIDForCurve(curve ecdh.Curve) (CurveID, bool) {
switch curve {
case ecdh.X25519():
return X25519, true
case ecdh.P256():
return CurveP256, true
case ecdh.P384():
return CurveP384, true
case ecdh.P521():
return CurveP521, true
default:
return 0, false
}
}

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// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !boringcrypto
package tls
func needFIPS() bool { return false }

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto"
"crypto/hmac"
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"errors"
"fmt"
"hash"
)
// Split a premaster secret in two as specified in RFC 4346, Section 5.
func splitPreMasterSecret(secret []byte) (s1, s2 []byte) {
s1 = secret[0 : (len(secret)+1)/2]
s2 = secret[len(secret)/2:]
return
}
// pHash implements the P_hash function, as defined in RFC 4346, Section 5.
func pHash(result, secret, seed []byte, hash func() hash.Hash) {
h := hmac.New(hash, secret)
h.Write(seed)
a := h.Sum(nil)
j := 0
for j < len(result) {
h.Reset()
h.Write(a)
h.Write(seed)
b := h.Sum(nil)
copy(result[j:], b)
j += len(b)
h.Reset()
h.Write(a)
a = h.Sum(nil)
}
}
// prf10 implements the TLS 1.0 pseudo-random function, as defined in RFC 2246, Section 5.
func prf10(result, secret, label, seed []byte) {
hashSHA1 := sha1.New
hashMD5 := md5.New
labelAndSeed := make([]byte, len(label)+len(seed))
copy(labelAndSeed, label)
copy(labelAndSeed[len(label):], seed)
s1, s2 := splitPreMasterSecret(secret)
pHash(result, s1, labelAndSeed, hashMD5)
result2 := make([]byte, len(result))
pHash(result2, s2, labelAndSeed, hashSHA1)
for i, b := range result2 {
result[i] ^= b
}
}
// prf12 implements the TLS 1.2 pseudo-random function, as defined in RFC 5246, Section 5.
func prf12(hashFunc func() hash.Hash) func(result, secret, label, seed []byte) {
return func(result, secret, label, seed []byte) {
labelAndSeed := make([]byte, len(label)+len(seed))
copy(labelAndSeed, label)
copy(labelAndSeed[len(label):], seed)
pHash(result, secret, labelAndSeed, hashFunc)
}
}
const (
masterSecretLength = 48 // Length of a master secret in TLS 1.1.
finishedVerifyLength = 12 // Length of verify_data in a Finished message.
)
var (
masterSecretLabel = []byte("master secret")
extendedMasterSecretLabel = []byte("extended master secret")
keyExpansionLabel = []byte("key expansion")
clientFinishedLabel = []byte("client finished")
serverFinishedLabel = []byte("server finished")
)
func prfAndHashForVersion(version uint16, suite *cipherSuite) (func(result, secret, label, seed []byte), crypto.Hash) {
switch version {
case VersionTLS10, VersionTLS11:
return prf10, crypto.Hash(0)
case VersionTLS12:
if suite.flags&suiteSHA384 != 0 {
return prf12(sha512.New384), crypto.SHA384
}
return prf12(sha256.New), crypto.SHA256
default:
panic("unknown version")
}
}
func prfForVersion(version uint16, suite *cipherSuite) func(result, secret, label, seed []byte) {
prf, _ := prfAndHashForVersion(version, suite)
return prf
}
// masterFromPreMasterSecret generates the master secret from the pre-master
// secret. See RFC 5246, Section 8.1.
func masterFromPreMasterSecret(version uint16, suite *cipherSuite, preMasterSecret, clientRandom, serverRandom []byte) []byte {
seed := make([]byte, 0, len(clientRandom)+len(serverRandom))
seed = append(seed, clientRandom...)
seed = append(seed, serverRandom...)
masterSecret := make([]byte, masterSecretLength)
prfForVersion(version, suite)(masterSecret, preMasterSecret, masterSecretLabel, seed)
return masterSecret
}
// extMasterFromPreMasterSecret generates the extended master secret from the
// pre-master secret. See RFC 7627.
func extMasterFromPreMasterSecret(version uint16, suite *cipherSuite, preMasterSecret, transcript []byte) []byte {
masterSecret := make([]byte, masterSecretLength)
prfForVersion(version, suite)(masterSecret, preMasterSecret, extendedMasterSecretLabel, transcript)
return masterSecret
}
// keysFromMasterSecret generates the connection keys from the master
// secret, given the lengths of the MAC key, cipher key and IV, as defined in
// RFC 2246, Section 6.3.
func keysFromMasterSecret(version uint16, suite *cipherSuite, masterSecret, clientRandom, serverRandom []byte, macLen, keyLen, ivLen int) (clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV []byte) {
seed := make([]byte, 0, len(serverRandom)+len(clientRandom))
seed = append(seed, serverRandom...)
seed = append(seed, clientRandom...)
n := 2*macLen + 2*keyLen + 2*ivLen
keyMaterial := make([]byte, n)
prfForVersion(version, suite)(keyMaterial, masterSecret, keyExpansionLabel, seed)
clientMAC = keyMaterial[:macLen]
keyMaterial = keyMaterial[macLen:]
serverMAC = keyMaterial[:macLen]
keyMaterial = keyMaterial[macLen:]
clientKey = keyMaterial[:keyLen]
keyMaterial = keyMaterial[keyLen:]
serverKey = keyMaterial[:keyLen]
keyMaterial = keyMaterial[keyLen:]
clientIV = keyMaterial[:ivLen]
keyMaterial = keyMaterial[ivLen:]
serverIV = keyMaterial[:ivLen]
return
}
func newFinishedHash(version uint16, cipherSuite *cipherSuite) finishedHash {
var buffer []byte
if version >= VersionTLS12 {
buffer = []byte{}
}
prf, hash := prfAndHashForVersion(version, cipherSuite)
if hash != 0 {
return finishedHash{hash.New(), hash.New(), nil, nil, buffer, version, prf}
}
return finishedHash{sha1.New(), sha1.New(), md5.New(), md5.New(), buffer, version, prf}
}
// A finishedHash calculates the hash of a set of handshake messages suitable
// for including in a Finished message.
type finishedHash struct {
client hash.Hash
server hash.Hash
// Prior to TLS 1.2, an additional MD5 hash is required.
clientMD5 hash.Hash
serverMD5 hash.Hash
// In TLS 1.2, a full buffer is sadly required.
buffer []byte
version uint16
prf func(result, secret, label, seed []byte)
}
func (h *finishedHash) Write(msg []byte) (n int, err error) {
h.client.Write(msg)
h.server.Write(msg)
if h.version < VersionTLS12 {
h.clientMD5.Write(msg)
h.serverMD5.Write(msg)
}
if h.buffer != nil {
h.buffer = append(h.buffer, msg...)
}
return len(msg), nil
}
func (h finishedHash) Sum() []byte {
if h.version >= VersionTLS12 {
return h.client.Sum(nil)
}
out := make([]byte, 0, md5.Size+sha1.Size)
out = h.clientMD5.Sum(out)
return h.client.Sum(out)
}
// clientSum returns the contents of the verify_data member of a client's
// Finished message.
func (h finishedHash) clientSum(masterSecret []byte) []byte {
out := make([]byte, finishedVerifyLength)
h.prf(out, masterSecret, clientFinishedLabel, h.Sum())
return out
}
// serverSum returns the contents of the verify_data member of a server's
// Finished message.
func (h finishedHash) serverSum(masterSecret []byte) []byte {
out := make([]byte, finishedVerifyLength)
h.prf(out, masterSecret, serverFinishedLabel, h.Sum())
return out
}
// hashForClientCertificate returns the handshake messages so far, pre-hashed if
// necessary, suitable for signing by a TLS client certificate.
func (h finishedHash) hashForClientCertificate(sigType uint8, hashAlg crypto.Hash) []byte {
if (h.version >= VersionTLS12 || sigType == signatureEd25519) && h.buffer == nil {
panic("tls: handshake hash for a client certificate requested after discarding the handshake buffer")
}
if sigType == signatureEd25519 {
return h.buffer
}
if h.version >= VersionTLS12 {
hash := hashAlg.New()
hash.Write(h.buffer)
return hash.Sum(nil)
}
if sigType == signatureECDSA {
return h.server.Sum(nil)
}
return h.Sum()
}
// discardHandshakeBuffer is called when there is no more need to
// buffer the entirety of the handshake messages.
func (h *finishedHash) discardHandshakeBuffer() {
h.buffer = nil
}
// noEKMBecauseRenegotiation is used as a value of
// ConnectionState.ekm when renegotiation is enabled and thus
// we wish to fail all key-material export requests.
func noEKMBecauseRenegotiation(label string, context []byte, length int) ([]byte, error) {
return nil, errors.New("crypto/tls: ExportKeyingMaterial is unavailable when renegotiation is enabled")
}
// noEKMBecauseNoEMS is used as a value of ConnectionState.ekm when Extended
// Master Secret is not negotiated and thus we wish to fail all key-material
// export requests.
func noEKMBecauseNoEMS(label string, context []byte, length int) ([]byte, error) {
return nil, errors.New("crypto/tls: ExportKeyingMaterial is unavailable when neither TLS 1.3 nor Extended Master Secret are negotiated; override with GODEBUG=tlsunsafeekm=1")
}
// ekmFromMasterSecret generates exported keying material as defined in RFC 5705.
func ekmFromMasterSecret(version uint16, suite *cipherSuite, masterSecret, clientRandom, serverRandom []byte) func(string, []byte, int) ([]byte, error) {
return func(label string, context []byte, length int) ([]byte, error) {
switch label {
case "client finished", "server finished", "master secret", "key expansion":
// These values are reserved and may not be used.
return nil, fmt.Errorf("crypto/tls: reserved ExportKeyingMaterial label: %s", label)
}
seedLen := len(serverRandom) + len(clientRandom)
if context != nil {
seedLen += 2 + len(context)
}
seed := make([]byte, 0, seedLen)
seed = append(seed, clientRandom...)
seed = append(seed, serverRandom...)
if context != nil {
if len(context) >= 1<<16 {
return nil, fmt.Errorf("crypto/tls: ExportKeyingMaterial context too long")
}
seed = append(seed, byte(len(context)>>8), byte(len(context)))
seed = append(seed, context...)
}
keyMaterial := make([]byte, length)
prfForVersion(version, suite)(keyMaterial, masterSecret, []byte(label), seed)
return keyMaterial, nil
}
}

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// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"context"
"errors"
"fmt"
)
// QUICEncryptionLevel represents a QUIC encryption level used to transmit
// handshake messages.
type QUICEncryptionLevel int
const (
QUICEncryptionLevelInitial = QUICEncryptionLevel(iota)
QUICEncryptionLevelEarly
QUICEncryptionLevelHandshake
QUICEncryptionLevelApplication
)
func (l QUICEncryptionLevel) String() string {
switch l {
case QUICEncryptionLevelInitial:
return "Initial"
case QUICEncryptionLevelEarly:
return "Early"
case QUICEncryptionLevelHandshake:
return "Handshake"
case QUICEncryptionLevelApplication:
return "Application"
default:
return fmt.Sprintf("QUICEncryptionLevel(%v)", int(l))
}
}
// A QUICConn represents a connection which uses a QUIC implementation as the underlying
// transport as described in RFC 9001.
//
// Methods of QUICConn are not safe for concurrent use.
type QUICConn struct {
conn *Conn
sessionTicketSent bool
}
// A QUICConfig configures a [QUICConn].
type QUICConfig struct {
TLSConfig *Config
// EnableSessionEvents may be set to true to enable the
// [QUICStoreSession] and [QUICResumeSession] events for client connections.
// When this event is enabled, sessions are not automatically
// stored in the client session cache.
// The application should use [QUICConn.StoreSession] to store sessions.
EnableSessionEvents bool
}
// A QUICEventKind is a type of operation on a QUIC connection.
type QUICEventKind int
const (
// QUICNoEvent indicates that there are no events available.
QUICNoEvent QUICEventKind = iota
// QUICSetReadSecret and QUICSetWriteSecret provide the read and write
// secrets for a given encryption level.
// QUICEvent.Level, QUICEvent.Data, and QUICEvent.Suite are set.
//
// Secrets for the Initial encryption level are derived from the initial
// destination connection ID, and are not provided by the QUICConn.
QUICSetReadSecret
QUICSetWriteSecret
// QUICWriteData provides data to send to the peer in CRYPTO frames.
// QUICEvent.Data is set.
QUICWriteData
// QUICTransportParameters provides the peer's QUIC transport parameters.
// QUICEvent.Data is set.
QUICTransportParameters
// QUICTransportParametersRequired indicates that the caller must provide
// QUIC transport parameters to send to the peer. The caller should set
// the transport parameters with QUICConn.SetTransportParameters and call
// QUICConn.NextEvent again.
//
// If transport parameters are set before calling QUICConn.Start, the
// connection will never generate a QUICTransportParametersRequired event.
QUICTransportParametersRequired
// QUICRejectedEarlyData indicates that the server rejected 0-RTT data even
// if we offered it. It's returned before QUICEncryptionLevelApplication
// keys are returned.
// This event only occurs on client connections.
QUICRejectedEarlyData
// QUICHandshakeDone indicates that the TLS handshake has completed.
QUICHandshakeDone
// QUICResumeSession indicates that a client is attempting to resume a previous session.
// [QUICEvent.SessionState] is set.
//
// For client connections, this event occurs when the session ticket is selected.
// For server connections, this event occurs when receiving the client's session ticket.
//
// The application may set [QUICEvent.SessionState.EarlyData] to false before the
// next call to [QUICConn.NextEvent] to decline 0-RTT even if the session supports it.
QUICResumeSession
// QUICStoreSession indicates that the server has provided state permitting
// the client to resume the session.
// [QUICEvent.SessionState] is set.
// The application should use [QUICConn.StoreSession] session to store the [SessionState].
// The application may modify the [SessionState] before storing it.
// This event only occurs on client connections.
QUICStoreSession
)
// A QUICEvent is an event occurring on a QUIC connection.
//
// The type of event is specified by the Kind field.
// The contents of the other fields are kind-specific.
type QUICEvent struct {
Kind QUICEventKind
// Set for QUICSetReadSecret, QUICSetWriteSecret, and QUICWriteData.
Level QUICEncryptionLevel
// Set for QUICTransportParameters, QUICSetReadSecret, QUICSetWriteSecret, and QUICWriteData.
// The contents are owned by crypto/tls, and are valid until the next NextEvent call.
Data []byte
// Set for QUICSetReadSecret and QUICSetWriteSecret.
Suite uint16
// Set for QUICResumeSession and QUICStoreSession.
SessionState *SessionState
}
type quicState struct {
events []QUICEvent
nextEvent int
// eventArr is a statically allocated event array, large enough to handle
// the usual maximum number of events resulting from a single call: transport
// parameters, Initial data, Early read secret, Handshake write and read
// secrets, Handshake data, Application write secret, Application data.
eventArr [8]QUICEvent
started bool
signalc chan struct{} // handshake data is available to be read
blockedc chan struct{} // handshake is waiting for data, closed when done
cancelc <-chan struct{} // handshake has been canceled
cancel context.CancelFunc
waitingForDrain bool
// readbuf is shared between HandleData and the handshake goroutine.
// HandshakeCryptoData passes ownership to the handshake goroutine by
// reading from signalc, and reclaims ownership by reading from blockedc.
readbuf []byte
transportParams []byte // to send to the peer
enableSessionEvents bool
}
// QUICClient returns a new TLS client side connection using QUICTransport as the
// underlying transport. The config cannot be nil.
//
// The config's MinVersion must be at least TLS 1.3.
func QUICClient(config *QUICConfig) *QUICConn {
return newQUICConn(Client(nil, config.TLSConfig), config)
}
// QUICServer returns a new TLS server side connection using QUICTransport as the
// underlying transport. The config cannot be nil.
//
// The config's MinVersion must be at least TLS 1.3.
func QUICServer(config *QUICConfig) *QUICConn {
return newQUICConn(Server(nil, config.TLSConfig), config)
}
func newQUICConn(conn *Conn, config *QUICConfig) *QUICConn {
conn.quic = &quicState{
signalc: make(chan struct{}),
blockedc: make(chan struct{}),
enableSessionEvents: config.EnableSessionEvents,
}
conn.quic.events = conn.quic.eventArr[:0]
return &QUICConn{
conn: conn,
}
}
// Start starts the client or server handshake protocol.
// It may produce connection events, which may be read with [QUICConn.NextEvent].
//
// Start must be called at most once.
func (q *QUICConn) Start(ctx context.Context) error {
if q.conn.quic.started {
return quicError(errors.New("tls: Start called more than once"))
}
q.conn.quic.started = true
if q.conn.config.MinVersion < VersionTLS13 {
return quicError(errors.New("tls: Config MinVersion must be at least TLS 1.13"))
}
go q.conn.HandshakeContext(ctx)
if _, ok := <-q.conn.quic.blockedc; !ok {
return q.conn.handshakeErr
}
return nil
}
// NextEvent returns the next event occurring on the connection.
// It returns an event with a Kind of [QUICNoEvent] when no events are available.
func (q *QUICConn) NextEvent() QUICEvent {
qs := q.conn.quic
if last := qs.nextEvent - 1; last >= 0 && len(qs.events[last].Data) > 0 {
// Write over some of the previous event's data,
// to catch callers erroniously retaining it.
qs.events[last].Data[0] = 0
}
if qs.nextEvent >= len(qs.events) && qs.waitingForDrain {
qs.waitingForDrain = false
<-qs.signalc
<-qs.blockedc
}
if qs.nextEvent >= len(qs.events) {
qs.events = qs.events[:0]
qs.nextEvent = 0
return QUICEvent{Kind: QUICNoEvent}
}
e := qs.events[qs.nextEvent]
qs.events[qs.nextEvent] = QUICEvent{} // zero out references to data
qs.nextEvent++
return e
}
// Close closes the connection and stops any in-progress handshake.
func (q *QUICConn) Close() error {
if q.conn.quic.cancel == nil {
return nil // never started
}
q.conn.quic.cancel()
for range q.conn.quic.blockedc {
// Wait for the handshake goroutine to return.
}
return q.conn.handshakeErr
}
// HandleData handles handshake bytes received from the peer.
// It may produce connection events, which may be read with [QUICConn.NextEvent].
func (q *QUICConn) HandleData(level QUICEncryptionLevel, data []byte) error {
c := q.conn
if c.in.level != level {
return quicError(c.in.setErrorLocked(errors.New("tls: handshake data received at wrong level")))
}
c.quic.readbuf = data
<-c.quic.signalc
_, ok := <-c.quic.blockedc
if ok {
// The handshake goroutine is waiting for more data.
return nil
}
// The handshake goroutine has exited.
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
c.hand.Write(c.quic.readbuf)
c.quic.readbuf = nil
for q.conn.hand.Len() >= 4 && q.conn.handshakeErr == nil {
b := q.conn.hand.Bytes()
n := int(b[1])<<16 | int(b[2])<<8 | int(b[3])
if n > maxHandshake {
q.conn.handshakeErr = fmt.Errorf("tls: handshake message of length %d bytes exceeds maximum of %d bytes", n, maxHandshake)
break
}
if len(b) < 4+n {
return nil
}
if err := q.conn.handlePostHandshakeMessage(); err != nil {
q.conn.handshakeErr = err
}
}
if q.conn.handshakeErr != nil {
return quicError(q.conn.handshakeErr)
}
return nil
}
type QUICSessionTicketOptions struct {
// EarlyData specifies whether the ticket may be used for 0-RTT.
EarlyData bool
Extra [][]byte
}
// SendSessionTicket sends a session ticket to the client.
// It produces connection events, which may be read with [QUICConn.NextEvent].
// Currently, it can only be called once.
func (q *QUICConn) SendSessionTicket(opts QUICSessionTicketOptions) error {
c := q.conn
if !c.isHandshakeComplete.Load() {
return quicError(errors.New("tls: SendSessionTicket called before handshake completed"))
}
if c.isClient {
return quicError(errors.New("tls: SendSessionTicket called on the client"))
}
if q.sessionTicketSent {
return quicError(errors.New("tls: SendSessionTicket called multiple times"))
}
q.sessionTicketSent = true
return quicError(c.sendSessionTicket(opts.EarlyData, opts.Extra))
}
// StoreSession stores a session previously received in a QUICStoreSession event
// in the ClientSessionCache.
// The application may process additional events or modify the SessionState
// before storing the session.
func (q *QUICConn) StoreSession(session *SessionState) error {
c := q.conn
if !c.isClient {
return quicError(errors.New("tls: StoreSessionTicket called on the server"))
}
cacheKey := c.clientSessionCacheKey()
if cacheKey == "" {
return nil
}
cs := &ClientSessionState{session: session}
c.config.ClientSessionCache.Put(cacheKey, cs)
return nil
}
// ConnectionState returns basic TLS details about the connection.
func (q *QUICConn) ConnectionState() ConnectionState {
return q.conn.ConnectionState()
}
// SetTransportParameters sets the transport parameters to send to the peer.
//
// Server connections may delay setting the transport parameters until after
// receiving the client's transport parameters. See [QUICTransportParametersRequired].
func (q *QUICConn) SetTransportParameters(params []byte) {
if params == nil {
params = []byte{}
}
q.conn.quic.transportParams = params
if q.conn.quic.started {
<-q.conn.quic.signalc
<-q.conn.quic.blockedc
}
}
// quicError ensures err is an AlertError.
// If err is not already, quicError wraps it with alertInternalError.
func quicError(err error) error {
if err == nil {
return nil
}
var ae AlertError
if errors.As(err, &ae) {
return err
}
var a alert
if !errors.As(err, &a) {
a = alertInternalError
}
// Return an error wrapping the original error and an AlertError.
// Truncate the text of the alert to 0 characters.
return fmt.Errorf("%w%.0w", err, AlertError(a))
}
func (c *Conn) quicReadHandshakeBytes(n int) error {
for c.hand.Len() < n {
if err := c.quicWaitForSignal(); err != nil {
return err
}
}
return nil
}
func (c *Conn) quicSetReadSecret(level QUICEncryptionLevel, suite uint16, secret []byte) {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICSetReadSecret,
Level: level,
Suite: suite,
Data: secret,
})
}
func (c *Conn) quicSetWriteSecret(level QUICEncryptionLevel, suite uint16, secret []byte) {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICSetWriteSecret,
Level: level,
Suite: suite,
Data: secret,
})
}
func (c *Conn) quicWriteCryptoData(level QUICEncryptionLevel, data []byte) {
var last *QUICEvent
if len(c.quic.events) > 0 {
last = &c.quic.events[len(c.quic.events)-1]
}
if last == nil || last.Kind != QUICWriteData || last.Level != level {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICWriteData,
Level: level,
})
last = &c.quic.events[len(c.quic.events)-1]
}
last.Data = append(last.Data, data...)
}
func (c *Conn) quicResumeSession(session *SessionState) error {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICResumeSession,
SessionState: session,
})
c.quic.waitingForDrain = true
for c.quic.waitingForDrain {
if err := c.quicWaitForSignal(); err != nil {
return err
}
}
return nil
}
func (c *Conn) quicStoreSession(session *SessionState) {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICStoreSession,
SessionState: session,
})
}
func (c *Conn) quicSetTransportParameters(params []byte) {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICTransportParameters,
Data: params,
})
}
func (c *Conn) quicGetTransportParameters() ([]byte, error) {
if c.quic.transportParams == nil {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICTransportParametersRequired,
})
}
for c.quic.transportParams == nil {
if err := c.quicWaitForSignal(); err != nil {
return nil, err
}
}
return c.quic.transportParams, nil
}
func (c *Conn) quicHandshakeComplete() {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICHandshakeDone,
})
}
func (c *Conn) quicRejectedEarlyData() {
c.quic.events = append(c.quic.events, QUICEvent{
Kind: QUICRejectedEarlyData,
})
}
// quicWaitForSignal notifies the QUICConn that handshake progress is blocked,
// and waits for a signal that the handshake should proceed.
//
// The handshake may become blocked waiting for handshake bytes
// or for the user to provide transport parameters.
func (c *Conn) quicWaitForSignal() error {
// Drop the handshake mutex while blocked to allow the user
// to call ConnectionState before the handshake completes.
c.handshakeMutex.Unlock()
defer c.handshakeMutex.Lock()
// Send on blockedc to notify the QUICConn that the handshake is blocked.
// Exported methods of QUICConn wait for the handshake to become blocked
// before returning to the user.
select {
case c.quic.blockedc <- struct{}{}:
case <-c.quic.cancelc:
return c.sendAlertLocked(alertCloseNotify)
}
// The QUICConn reads from signalc to notify us that the handshake may
// be able to proceed. (The QUICConn reads, because we close signalc to
// indicate that the handshake has completed.)
select {
case c.quic.signalc <- struct{}{}:
c.hand.Write(c.quic.readbuf)
c.quic.readbuf = nil
case <-c.quic.cancelc:
return c.sendAlertLocked(alertCloseNotify)
}
return nil
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto/aes"
"crypto/cipher"
"crypto/hmac"
"crypto/sha256"
"crypto/subtle"
"crypto/x509"
"errors"
"io"
"golang.org/x/crypto/cryptobyte"
)
// A SessionState is a resumable session.
type SessionState struct {
// Encoded as a SessionState (in the language of RFC 8446, Section 3).
//
// enum { server(1), client(2) } SessionStateType;
//
// opaque Certificate<1..2^24-1>;
//
// Certificate CertificateChain<0..2^24-1>;
//
// opaque Extra<0..2^24-1>;
//
// struct {
// uint16 version;
// SessionStateType type;
// uint16 cipher_suite;
// uint64 created_at;
// opaque secret<1..2^8-1>;
// Extra extra<0..2^24-1>;
// uint8 ext_master_secret = { 0, 1 };
// uint8 early_data = { 0, 1 };
// CertificateEntry certificate_list<0..2^24-1>;
// CertificateChain verified_chains<0..2^24-1>; /* excluding leaf */
// select (SessionState.early_data) {
// case 0: Empty;
// case 1: opaque alpn<1..2^8-1>;
// };
// select (SessionState.type) {
// case server: Empty;
// case client: struct {
// select (SessionState.version) {
// case VersionTLS10..VersionTLS12: Empty;
// case VersionTLS13: struct {
// uint64 use_by;
// uint32 age_add;
// };
// };
// };
// };
// } SessionState;
//
// Extra is ignored by crypto/tls, but is encoded by [SessionState.Bytes]
// and parsed by [ParseSessionState].
//
// This allows [Config.UnwrapSession]/[Config.WrapSession] and
// [ClientSessionCache] implementations to store and retrieve additional
// data alongside this session.
//
// To allow different layers in a protocol stack to share this field,
// applications must only append to it, not replace it, and must use entries
// that can be recognized even if out of order (for example, by starting
// with an id and version prefix).
Extra [][]byte
// EarlyData indicates whether the ticket can be used for 0-RTT in a QUIC
// connection. The application may set this to false if it is true to
// decline to offer 0-RTT even if supported.
EarlyData bool
version uint16
isClient bool
cipherSuite uint16
// createdAt is the generation time of the secret on the sever (which for
// TLS 1.0–1.2 might be earlier than the current session) and the time at
// which the ticket was received on the client.
createdAt uint64 // seconds since UNIX epoch
secret []byte // master secret for TLS 1.2, or the PSK for TLS 1.3
extMasterSecret bool
peerCertificates []*x509.Certificate
activeCertHandles []*activeCert
ocspResponse []byte
scts [][]byte
verifiedChains [][]*x509.Certificate
alpnProtocol string // only set if EarlyData is true
// Client-side TLS 1.3-only fields.
useBy uint64 // seconds since UNIX epoch
ageAdd uint32
ticket []byte
}
// Bytes encodes the session, including any private fields, so that it can be
// parsed by [ParseSessionState]. The encoding contains secret values critical
// to the security of future and possibly past sessions.
//
// The specific encoding should be considered opaque and may change incompatibly
// between Go versions.
func (s *SessionState) Bytes() ([]byte, error) {
var b cryptobyte.Builder
b.AddUint16(s.version)
if s.isClient {
b.AddUint8(2) // client
} else {
b.AddUint8(1) // server
}
b.AddUint16(s.cipherSuite)
addUint64(&b, s.createdAt)
b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes(s.secret)
})
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
for _, extra := range s.Extra {
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes(extra)
})
}
})
if s.extMasterSecret {
b.AddUint8(1)
} else {
b.AddUint8(0)
}
if s.EarlyData {
b.AddUint8(1)
} else {
b.AddUint8(0)
}
marshalCertificate(&b, Certificate{
Certificate: certificatesToBytesSlice(s.peerCertificates),
OCSPStaple: s.ocspResponse,
SignedCertificateTimestamps: s.scts,
})
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
for _, chain := range s.verifiedChains {
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
// We elide the first certificate because it's always the leaf.
if len(chain) == 0 {
b.SetError(errors.New("tls: internal error: empty verified chain"))
return
}
for _, cert := range chain[1:] {
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes(cert.Raw)
})
}
})
}
})
if s.EarlyData {
b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes([]byte(s.alpnProtocol))
})
}
if s.isClient {
if s.version >= VersionTLS13 {
addUint64(&b, s.useBy)
b.AddUint32(s.ageAdd)
}
}
return b.Bytes()
}
func certificatesToBytesSlice(certs []*x509.Certificate) [][]byte {
s := make([][]byte, 0, len(certs))
for _, c := range certs {
s = append(s, c.Raw)
}
return s
}
// ParseSessionState parses a [SessionState] encoded by [SessionState.Bytes].
func ParseSessionState(data []byte) (*SessionState, error) {
ss := &SessionState{}
s := cryptobyte.String(data)
var typ, extMasterSecret, earlyData uint8
var cert Certificate
var extra cryptobyte.String
if !s.ReadUint16(&ss.version) ||
!s.ReadUint8(&typ) ||
(typ != 1 && typ != 2) ||
!s.ReadUint16(&ss.cipherSuite) ||
!readUint64(&s, &ss.createdAt) ||
!readUint8LengthPrefixed(&s, &ss.secret) ||
!s.ReadUint24LengthPrefixed(&extra) ||
!s.ReadUint8(&extMasterSecret) ||
!s.ReadUint8(&earlyData) ||
len(ss.secret) == 0 ||
!unmarshalCertificate(&s, &cert) {
return nil, errors.New("tls: invalid session encoding")
}
for !extra.Empty() {
var e []byte
if !readUint24LengthPrefixed(&extra, &e) {
return nil, errors.New("tls: invalid session encoding")
}
ss.Extra = append(ss.Extra, e)
}
switch extMasterSecret {
case 0:
ss.extMasterSecret = false
case 1:
ss.extMasterSecret = true
default:
return nil, errors.New("tls: invalid session encoding")
}
switch earlyData {
case 0:
ss.EarlyData = false
case 1:
ss.EarlyData = true
default:
return nil, errors.New("tls: invalid session encoding")
}
for _, cert := range cert.Certificate {
c, err := globalCertCache.newCert(cert)
if err != nil {
return nil, err
}
ss.activeCertHandles = append(ss.activeCertHandles, c)
ss.peerCertificates = append(ss.peerCertificates, c.cert)
}
ss.ocspResponse = cert.OCSPStaple
ss.scts = cert.SignedCertificateTimestamps
var chainList cryptobyte.String
if !s.ReadUint24LengthPrefixed(&chainList) {
return nil, errors.New("tls: invalid session encoding")
}
for !chainList.Empty() {
var certList cryptobyte.String
if !chainList.ReadUint24LengthPrefixed(&certList) {
return nil, errors.New("tls: invalid session encoding")
}
var chain []*x509.Certificate
if len(ss.peerCertificates) == 0 {
return nil, errors.New("tls: invalid session encoding")
}
chain = append(chain, ss.peerCertificates[0])
for !certList.Empty() {
var cert []byte
if !readUint24LengthPrefixed(&certList, &cert) {
return nil, errors.New("tls: invalid session encoding")
}
c, err := globalCertCache.newCert(cert)
if err != nil {
return nil, err
}
ss.activeCertHandles = append(ss.activeCertHandles, c)
chain = append(chain, c.cert)
}
ss.verifiedChains = append(ss.verifiedChains, chain)
}
if ss.EarlyData {
var alpn []byte
if !readUint8LengthPrefixed(&s, &alpn) {
return nil, errors.New("tls: invalid session encoding")
}
ss.alpnProtocol = string(alpn)
}
if isClient := typ == 2; !isClient {
if !s.Empty() {
return nil, errors.New("tls: invalid session encoding")
}
return ss, nil
}
ss.isClient = true
if len(ss.peerCertificates) == 0 {
return nil, errors.New("tls: no server certificates in client session")
}
if ss.version < VersionTLS13 {
if !s.Empty() {
return nil, errors.New("tls: invalid session encoding")
}
return ss, nil
}
if !s.ReadUint64(&ss.useBy) || !s.ReadUint32(&ss.ageAdd) || !s.Empty() {
return nil, errors.New("tls: invalid session encoding")
}
return ss, nil
}
// sessionState returns a partially filled-out [SessionState] with information
// from the current connection.
func (c *Conn) sessionState() *SessionState {
return &SessionState{
version: c.vers,
cipherSuite: c.cipherSuite,
createdAt: uint64(c.config.time().Unix()),
alpnProtocol: c.clientProtocol,
peerCertificates: c.peerCertificates,
activeCertHandles: c.activeCertHandles,
ocspResponse: c.ocspResponse,
scts: c.scts,
isClient: c.isClient,
extMasterSecret: c.extMasterSecret,
verifiedChains: c.verifiedChains,
}
}
// EncryptTicket encrypts a ticket with the [Config]'s configured (or default)
// session ticket keys. It can be used as a [Config.WrapSession] implementation.
func (c *Config) EncryptTicket(cs ConnectionState, ss *SessionState) ([]byte, error) {
ticketKeys := c.ticketKeys(nil)
stateBytes, err := ss.Bytes()
if err != nil {
return nil, err
}
return c.encryptTicket(stateBytes, ticketKeys)
}
func (c *Config) encryptTicket(state []byte, ticketKeys []ticketKey) ([]byte, error) {
if len(ticketKeys) == 0 {
return nil, errors.New("tls: internal error: session ticket keys unavailable")
}
encrypted := make([]byte, aes.BlockSize+len(state)+sha256.Size)
iv := encrypted[:aes.BlockSize]
ciphertext := encrypted[aes.BlockSize : len(encrypted)-sha256.Size]
authenticated := encrypted[:len(encrypted)-sha256.Size]
macBytes := encrypted[len(encrypted)-sha256.Size:]
if _, err := io.ReadFull(c.rand(), iv); err != nil {
return nil, err
}
key := ticketKeys[0]
block, err := aes.NewCipher(key.aesKey[:])
if err != nil {
return nil, errors.New("tls: failed to create cipher while encrypting ticket: " + err.Error())
}
cipher.NewCTR(block, iv).XORKeyStream(ciphertext, state)
mac := hmac.New(sha256.New, key.hmacKey[:])
mac.Write(authenticated)
mac.Sum(macBytes[:0])
return encrypted, nil
}
// DecryptTicket decrypts a ticket encrypted by [Config.EncryptTicket]. It can
// be used as a [Config.UnwrapSession] implementation.
//
// If the ticket can't be decrypted or parsed, DecryptTicket returns (nil, nil).
func (c *Config) DecryptTicket(identity []byte, cs ConnectionState) (*SessionState, error) {
ticketKeys := c.ticketKeys(nil)
stateBytes := c.decryptTicket(identity, ticketKeys)
if stateBytes == nil {
return nil, nil
}
s, err := ParseSessionState(stateBytes)
if err != nil {
return nil, nil // drop unparsable tickets on the floor
}
return s, nil
}
func (c *Config) decryptTicket(encrypted []byte, ticketKeys []ticketKey) []byte {
if len(encrypted) < aes.BlockSize+sha256.Size {
return nil
}
iv := encrypted[:aes.BlockSize]
ciphertext := encrypted[aes.BlockSize : len(encrypted)-sha256.Size]
authenticated := encrypted[:len(encrypted)-sha256.Size]
macBytes := encrypted[len(encrypted)-sha256.Size:]
for _, key := range ticketKeys {
mac := hmac.New(sha256.New, key.hmacKey[:])
mac.Write(authenticated)
expected := mac.Sum(nil)
if subtle.ConstantTimeCompare(macBytes, expected) != 1 {
continue
}
block, err := aes.NewCipher(key.aesKey[:])
if err != nil {
return nil
}
plaintext := make([]byte, len(ciphertext))
cipher.NewCTR(block, iv).XORKeyStream(plaintext, ciphertext)
return plaintext
}
return nil
}
// ClientSessionState contains the state needed by a client to
// resume a previous TLS session.
type ClientSessionState struct {
session *SessionState
}
// ResumptionState returns the session ticket sent by the server (also known as
// the session's identity) and the state necessary to resume this session.
//
// It can be called by [ClientSessionCache.Put] to serialize (with
// [SessionState.Bytes]) and store the session.
func (cs *ClientSessionState) ResumptionState() (ticket []byte, state *SessionState, err error) {
if cs == nil || cs.session == nil {
return nil, nil, nil
}
return cs.session.ticket, cs.session, nil
}
// NewResumptionState returns a state value that can be returned by
// [ClientSessionCache.Get] to resume a previous session.
//
// state needs to be returned by [ParseSessionState], and the ticket and session
// state must have been returned by [ClientSessionState.ResumptionState].
func NewResumptionState(ticket []byte, state *SessionState) (*ClientSessionState, error) {
state.ticket = ticket
return &ClientSessionState{
session: state,
}, nil
}

364
internal/tls/tls.go Normal file
View file

@ -0,0 +1,364 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tls partially implements TLS 1.2, as specified in RFC 5246,
// and TLS 1.3, as specified in RFC 8446.
package tls
// BUG(agl): The crypto/tls package only implements some countermeasures
// against Lucky13 attacks on CBC-mode encryption, and only on SHA1
// variants. See http://www.isg.rhul.ac.uk/tls/TLStiming.pdf and
// https://www.imperialviolet.org/2013/02/04/luckythirteen.html.
import (
"bytes"
"context"
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"net"
"os"
"strings"
)
// Server returns a new TLS server side connection
// using conn as the underlying transport.
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func Server(conn net.Conn, config *Config) *Conn {
c := &Conn{
conn: conn,
config: config,
}
c.handshakeFn = c.serverHandshake
return c
}
// Client returns a new TLS client side connection
// using conn as the underlying transport.
// The config cannot be nil: users must set either ServerName or
// InsecureSkipVerify in the config.
func Client(conn net.Conn, config *Config) *Conn {
c := &Conn{
conn: conn,
config: config,
isClient: true,
}
c.handshakeFn = c.clientHandshake
return c
}
// A listener implements a network listener (net.Listener) for TLS connections.
type listener struct {
net.Listener
config *Config
}
// Accept waits for and returns the next incoming TLS connection.
// The returned connection is of type *Conn.
func (l *listener) Accept() (net.Conn, error) {
c, err := l.Listener.Accept()
if err != nil {
return nil, err
}
return Server(c, l.config), nil
}
// NewListener creates a Listener which accepts connections from an inner
// Listener and wraps each connection with [Server].
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func NewListener(inner net.Listener, config *Config) net.Listener {
l := new(listener)
l.Listener = inner
l.config = config
return l
}
// Listen creates a TLS listener accepting connections on the
// given network address using net.Listen.
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func Listen(network, laddr string, config *Config) (net.Listener, error) {
// If this condition changes, consider updating http.Server.ServeTLS too.
if config == nil || len(config.Certificates) == 0 &&
config.GetCertificate == nil && config.GetConfigForClient == nil {
return nil, errors.New("tls: neither Certificates, GetCertificate, nor GetConfigForClient set in Config")
}
l, err := net.Listen(network, laddr)
if err != nil {
return nil, err
}
return NewListener(l, config), nil
}
type timeoutError struct{}
func (timeoutError) Error() string { return "tls: DialWithDialer timed out" }
func (timeoutError) Timeout() bool { return true }
func (timeoutError) Temporary() bool { return true }
// DialWithDialer connects to the given network address using dialer.Dial and
// then initiates a TLS handshake, returning the resulting TLS connection. Any
// timeout or deadline given in the dialer apply to connection and TLS
// handshake as a whole.
//
// DialWithDialer interprets a nil configuration as equivalent to the zero
// configuration; see the documentation of [Config] for the defaults.
//
// DialWithDialer uses context.Background internally; to specify the context,
// use [Dialer.DialContext] with NetDialer set to the desired dialer.
func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) {
return dial(context.Background(), dialer, network, addr, config)
}
func dial(ctx context.Context, netDialer *net.Dialer, network, addr string, config *Config) (*Conn, error) {
if netDialer.Timeout != 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, netDialer.Timeout)
defer cancel()
}
if !netDialer.Deadline.IsZero() {
var cancel context.CancelFunc
ctx, cancel = context.WithDeadline(ctx, netDialer.Deadline)
defer cancel()
}
rawConn, err := netDialer.DialContext(ctx, network, addr)
if err != nil {
return nil, err
}
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
hostname := addr[:colonPos]
if config == nil {
config = defaultConfig()
}
// If no ServerName is set, infer the ServerName
// from the hostname we're connecting to.
if config.ServerName == "" {
// Make a copy to avoid polluting argument or default.
c := config.Clone()
c.ServerName = hostname
config = c
}
conn := Client(rawConn, config)
if err := conn.HandshakeContext(ctx); err != nil {
rawConn.Close()
return nil, err
}
return conn, nil
}
// Dial connects to the given network address using net.Dial
// and then initiates a TLS handshake, returning the resulting
// TLS connection.
// Dial interprets a nil configuration as equivalent to
// the zero configuration; see the documentation of Config
// for the defaults.
func Dial(network, addr string, config *Config) (*Conn, error) {
return DialWithDialer(new(net.Dialer), network, addr, config)
}
// Dialer dials TLS connections given a configuration and a Dialer for the
// underlying connection.
type Dialer struct {
// NetDialer is the optional dialer to use for the TLS connections'
// underlying TCP connections.
// A nil NetDialer is equivalent to the net.Dialer zero value.
NetDialer *net.Dialer
// Config is the TLS configuration to use for new connections.
// A nil configuration is equivalent to the zero
// configuration; see the documentation of Config for the
// defaults.
Config *Config
}
// Dial connects to the given network address and initiates a TLS
// handshake, returning the resulting TLS connection.
//
// The returned [Conn], if any, will always be of type *[Conn].
//
// Dial uses context.Background internally; to specify the context,
// use [Dialer.DialContext].
func (d *Dialer) Dial(network, addr string) (net.Conn, error) {
return d.DialContext(context.Background(), network, addr)
}
func (d *Dialer) netDialer() *net.Dialer {
if d.NetDialer != nil {
return d.NetDialer
}
return new(net.Dialer)
}
// DialContext connects to the given network address and initiates a TLS
// handshake, returning the resulting TLS connection.
//
// The provided Context must be non-nil. If the context expires before
// the connection is complete, an error is returned. Once successfully
// connected, any expiration of the context will not affect the
// connection.
//
// The returned [Conn], if any, will always be of type *[Conn].
func (d *Dialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
c, err := dial(ctx, d.netDialer(), network, addr, d.Config)
if err != nil {
// Don't return c (a typed nil) in an interface.
return nil, err
}
return c, nil
}
// LoadX509KeyPair reads and parses a public/private key pair from a pair of
// files. The files must contain PEM encoded data. The certificate file may
// contain intermediate certificates following the leaf certificate to form a
// certificate chain. On successful return, Certificate.Leaf will be populated.
//
// Before Go 1.23 Certificate.Leaf was left nil, and the parsed certificate was
// discarded. This behavior can be re-enabled by setting "x509keypairleaf=0"
// in the GODEBUG environment variable.
func LoadX509KeyPair(certFile, keyFile string) (Certificate, error) {
certPEMBlock, err := os.ReadFile(certFile)
if err != nil {
return Certificate{}, err
}
keyPEMBlock, err := os.ReadFile(keyFile)
if err != nil {
return Certificate{}, err
}
return X509KeyPair(certPEMBlock, keyPEMBlock)
}
// X509KeyPair parses a public/private key pair from a pair of
// PEM encoded data. On successful return, Certificate.Leaf will be populated.
//
// Before Go 1.23 Certificate.Leaf was left nil, and the parsed certificate was
// discarded. This behavior can be re-enabled by setting "x509keypairleaf=0"
// in the GODEBUG environment variable.
func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error) {
fail := func(err error) (Certificate, error) { return Certificate{}, err }
var cert Certificate
var skippedBlockTypes []string
for {
var certDERBlock *pem.Block
certDERBlock, certPEMBlock = pem.Decode(certPEMBlock)
if certDERBlock == nil {
break
}
if certDERBlock.Type == "CERTIFICATE" {
cert.Certificate = append(cert.Certificate, certDERBlock.Bytes)
} else {
skippedBlockTypes = append(skippedBlockTypes, certDERBlock.Type)
}
}
if len(cert.Certificate) == 0 {
if len(skippedBlockTypes) == 0 {
return fail(errors.New("tls: failed to find any PEM data in certificate input"))
}
if len(skippedBlockTypes) == 1 && strings.HasSuffix(skippedBlockTypes[0], "PRIVATE KEY") {
return fail(errors.New("tls: failed to find certificate PEM data in certificate input, but did find a private key; PEM inputs may have been switched"))
}
return fail(fmt.Errorf("tls: failed to find \"CERTIFICATE\" PEM block in certificate input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
}
skippedBlockTypes = skippedBlockTypes[:0]
var keyDERBlock *pem.Block
for {
keyDERBlock, keyPEMBlock = pem.Decode(keyPEMBlock)
if keyDERBlock == nil {
if len(skippedBlockTypes) == 0 {
return fail(errors.New("tls: failed to find any PEM data in key input"))
}
if len(skippedBlockTypes) == 1 && skippedBlockTypes[0] == "CERTIFICATE" {
return fail(errors.New("tls: found a certificate rather than a key in the PEM for the private key"))
}
return fail(fmt.Errorf("tls: failed to find PEM block with type ending in \"PRIVATE KEY\" in key input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
}
if keyDERBlock.Type == "PRIVATE KEY" || strings.HasSuffix(keyDERBlock.Type, " PRIVATE KEY") {
break
}
skippedBlockTypes = append(skippedBlockTypes, keyDERBlock.Type)
}
// We don't need to parse the public key for TLS, but we so do anyway
// to check that it looks sane and matches the private key.
x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
if err != nil {
return fail(err)
}
cert.Leaf = x509Cert
cert.PrivateKey, err = parsePrivateKey(keyDERBlock.Bytes)
if err != nil {
return fail(err)
}
switch pub := x509Cert.PublicKey.(type) {
case *rsa.PublicKey:
priv, ok := cert.PrivateKey.(*rsa.PrivateKey)
if !ok {
return fail(errors.New("tls: private key type does not match public key type"))
}
if pub.N.Cmp(priv.N) != 0 {
return fail(errors.New("tls: private key does not match public key"))
}
case *ecdsa.PublicKey:
priv, ok := cert.PrivateKey.(*ecdsa.PrivateKey)
if !ok {
return fail(errors.New("tls: private key type does not match public key type"))
}
if pub.X.Cmp(priv.X) != 0 || pub.Y.Cmp(priv.Y) != 0 {
return fail(errors.New("tls: private key does not match public key"))
}
case ed25519.PublicKey:
priv, ok := cert.PrivateKey.(ed25519.PrivateKey)
if !ok {
return fail(errors.New("tls: private key type does not match public key type"))
}
if !bytes.Equal(priv.Public().(ed25519.PublicKey), pub) {
return fail(errors.New("tls: private key does not match public key"))
}
default:
return fail(errors.New("tls: unknown public key algorithm"))
}
return cert, nil
}
// Attempt to parse the given private key DER block. OpenSSL 0.9.8 generates
// PKCS #1 private keys by default, while OpenSSL 1.0.0 generates PKCS #8 keys.
// OpenSSL ecparam generates SEC1 EC private keys for ECDSA. We try all three.
func parsePrivateKey(der []byte) (crypto.PrivateKey, error) {
if key, err := x509.ParsePKCS1PrivateKey(der); err == nil {
return key, nil
}
if key, err := x509.ParsePKCS8PrivateKey(der); err == nil {
switch key := key.(type) {
case *rsa.PrivateKey, *ecdsa.PrivateKey, ed25519.PrivateKey:
return key, nil
default:
return nil, errors.New("tls: found unknown private key type in PKCS#8 wrapping")
}
}
if key, err := x509.ParseECPrivateKey(der); err == nil {
return key, nil
}
return nil, errors.New("tls: failed to parse private key")
}

2
tls.go
View file

@ -1,7 +1,7 @@
package shadowtls
import (
sTLS "github.com/sagernet/sing-shadowtls/tls"
sTLS "github.com/sagernet/sing-shadowtls/internal/tls"
)
type (