mirror of
https://github.com/refraction-networking/utls.git
synced 2025-04-03 20:17:36 +03:00
feat: Convert raw bytes or tlsfingerprint record to ClientHelloSpec (#168)
* feat: byte to clienthellospecs conversion * feat: specific case for GREASE and ALPS Will automatically add "h2" to ALPS and write to log when GREASE extension is imported in `ImportTLSClientHello()` * fix: ReadCompressionMethods ReadCompressionMethods didn't advance the s and fails reading extensions * fix: remove debug log * fix: use cryptobyte for internal helper `helper.Uint8to16()` now calls `(*cryptobyte.String).ReadUint16()` * fix: preshared key fingerprinter test updated fingerprinter test to test with PreSharedKey extension * fix: naming of FakePreSharedKeyExt It is a Fake extension since `crypto/tls` doesn't really implement PSK-based resumption and neither do we. * feat: Properly check GREASE Adopted from #148. Co-Authored-By: gfw-report <gfw.report@protonmail.com> * feat: add fakeExtensionEncryptThenMAC And reordered `fakeExtensionDelegatedCredentials`. The new `Fingerprinter` is expected to account for the `fakeExtensionEncryptThenMAC` using a `GenericExtension` when `allowBluntMimicry` is set. Co-Authored-By: gfw-report <gfw.report@protonmail.com> * fix: remove keepPSK and minor - Removed all presence of keepPSK flag. - Added check before using the field of a map. --------- Co-authored-by: gfw-report <gfw.report@protonmail.com>
This commit is contained in:
Gaukas Wang
GitHub
parent
71b4ad3909
commit
dae72adb81
10 changed files with 961 additions and 366 deletions
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@ -6,16 +6,12 @@ package tls
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import (
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"errors"
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"fmt"
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"strings"
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"golang.org/x/crypto/cryptobyte"
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)
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// Fingerprinter is a struct largely for holding options for the FingerprintClientHello func
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type Fingerprinter struct {
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// KeepPSK will ensure that the PreSharedKey extension is passed along into the resulting ClientHelloSpec as-is
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KeepPSK bool
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// AllowBluntMimicry will ensure that unknown extensions are
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// passed along into the resulting ClientHelloSpec as-is
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// It will not ensure that the PSK is passed along, if you require that, use KeepPSK
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@ -40,8 +36,8 @@ type Fingerprinter struct {
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// as well as the handshake type/length/version header
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// https://tools.ietf.org/html/rfc5246#section-6.2
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// https://tools.ietf.org/html/rfc5246#section-7.4
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func (f *Fingerprinter) FingerprintClientHello(data []byte) (*ClientHelloSpec, error) {
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clientHelloSpec := &ClientHelloSpec{}
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func (f *Fingerprinter) FingerprintClientHello(data []byte) (clientHelloSpec *ClientHelloSpec, err error) {
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clientHelloSpec = &ClientHelloSpec{}
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s := cryptobyte.String(data)
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var contentType uint8
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@ -75,23 +71,25 @@ func (f *Fingerprinter) FingerprintClientHello(data []byte) (*ClientHelloSpec, e
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return nil, errors.New("unable to read session id")
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}
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// CipherSuites
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var cipherSuitesBytes cryptobyte.String
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if !s.ReadUint16LengthPrefixed(&cipherSuitesBytes) {
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return nil, errors.New("unable to read ciphersuites")
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}
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cipherSuites := []uint16{}
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for !cipherSuitesBytes.Empty() {
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var suite uint16
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if !cipherSuitesBytes.ReadUint16(&suite) {
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return nil, errors.New("unable to read ciphersuite")
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}
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cipherSuites = append(cipherSuites, unGREASEUint16(suite))
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err = clientHelloSpec.ReadCipherSuites(cipherSuitesBytes)
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if err != nil {
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return nil, err
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}
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clientHelloSpec.CipherSuites = cipherSuites
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if !readUint8LengthPrefixed(&s, &clientHelloSpec.CompressionMethods) {
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// CompressionMethods
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var compressionMethods cryptobyte.String
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if !s.ReadUint8LengthPrefixed(&compressionMethods) {
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return nil, errors.New("unable to read compression methods")
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}
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err = clientHelloSpec.ReadCompressionMethods(compressionMethods)
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if err != nil {
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return nil, err
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}
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if s.Empty() {
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// ClientHello is optionally followed by extension data
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@ -103,327 +101,13 @@ func (f *Fingerprinter) FingerprintClientHello(data []byte) (*ClientHelloSpec, e
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return nil, errors.New("unable to read extensions data")
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}
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for !extensions.Empty() {
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var extension uint16
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var extData cryptobyte.String
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if !extensions.ReadUint16(&extension) ||
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!extensions.ReadUint16LengthPrefixed(&extData) {
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return nil, errors.New("unable to read extension data")
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}
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switch extension {
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case extensionServerName:
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// RFC 6066, Section 3
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var nameList cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&nameList) || nameList.Empty() {
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return nil, errors.New("unable to read server name extension data")
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}
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var serverName string
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for !nameList.Empty() {
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var nameType uint8
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var serverNameBytes cryptobyte.String
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if !nameList.ReadUint8(&nameType) ||
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!nameList.ReadUint16LengthPrefixed(&serverNameBytes) ||
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serverNameBytes.Empty() {
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return nil, errors.New("unable to read server name extension data")
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}
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if nameType != 0 {
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continue
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}
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if len(serverName) != 0 {
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return nil, errors.New("multiple names of the same name_type in server name extension are prohibited")
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}
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serverName = string(serverNameBytes)
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if strings.HasSuffix(serverName, ".") {
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return nil, errors.New("SNI value may not include a trailing dot")
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SNIExtension{})
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}
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case extensionNextProtoNeg:
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// draft-agl-tls-nextprotoneg-04
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &NPNExtension{})
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case extensionStatusRequest:
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// RFC 4366, Section 3.6
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var statusType uint8
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var ignored cryptobyte.String
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if !extData.ReadUint8(&statusType) ||
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!extData.ReadUint16LengthPrefixed(&ignored) ||
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!extData.ReadUint16LengthPrefixed(&ignored) {
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return nil, errors.New("unable to read status request extension data")
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}
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if statusType == statusTypeOCSP {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &StatusRequestExtension{})
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} else {
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return nil, errors.New("status request extension statusType is not statusTypeOCSP")
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}
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case extensionSupportedCurves:
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// RFC 4492, sections 5.1.1 and RFC 8446, Section 4.2.7
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var curvesBytes cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&curvesBytes) || curvesBytes.Empty() {
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return nil, errors.New("unable to read supported curves extension data")
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}
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curves := []CurveID{}
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for !curvesBytes.Empty() {
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var curve uint16
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if !curvesBytes.ReadUint16(&curve) {
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return nil, errors.New("unable to read supported curves extension data")
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}
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curves = append(curves, CurveID(unGREASEUint16(curve)))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SupportedCurvesExtension{curves})
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case extensionSupportedPoints:
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// RFC 4492, Section 5.1.2
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supportedPoints := []uint8{}
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if !readUint8LengthPrefixed(&extData, &supportedPoints) ||
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len(supportedPoints) == 0 {
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return nil, errors.New("unable to read supported points extension data")
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SupportedPointsExtension{supportedPoints})
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case extensionSessionTicket:
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// RFC 5077, Section 3.2
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SessionTicketExtension{})
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case extensionSignatureAlgorithms:
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// RFC 5246, Section 7.4.1.4.1
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var sigAndAlgs cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&sigAndAlgs) || sigAndAlgs.Empty() {
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return nil, errors.New("unable to read signature algorithms extension data")
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}
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supportedSignatureAlgorithms := []SignatureScheme{}
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for !sigAndAlgs.Empty() {
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var sigAndAlg uint16
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if !sigAndAlgs.ReadUint16(&sigAndAlg) {
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return nil, errors.New("unable to read signature algorithms extension data")
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}
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supportedSignatureAlgorithms = append(
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supportedSignatureAlgorithms, SignatureScheme(sigAndAlg))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SignatureAlgorithmsExtension{supportedSignatureAlgorithms})
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case extensionSignatureAlgorithmsCert:
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// RFC 8446, Section 4.2.3
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if f.AllowBluntMimicry {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &GenericExtension{extension, extData})
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} else {
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return nil, errors.New("unsupported extension SignatureAlgorithmsCert")
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}
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case extensionRenegotiationInfo:
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// RFC 5746, Section 3.2
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &RenegotiationInfoExtension{RenegotiateOnceAsClient})
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case extensionALPN:
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// RFC 7301, Section 3.1
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var protoList cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&protoList) || protoList.Empty() {
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return nil, errors.New("unable to read ALPN extension data")
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}
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alpnProtocols := []string{}
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for !protoList.Empty() {
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var proto cryptobyte.String
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if !protoList.ReadUint8LengthPrefixed(&proto) || proto.Empty() {
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return nil, errors.New("unable to read ALPN extension data")
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}
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alpnProtocols = append(alpnProtocols, string(proto))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &ALPNExtension{alpnProtocols})
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case extensionSCT:
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// RFC 6962, Section 3.3.1
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SCTExtension{})
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case extensionSupportedVersions:
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// RFC 8446, Section 4.2.1
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var versList cryptobyte.String
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if !extData.ReadUint8LengthPrefixed(&versList) || versList.Empty() {
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return nil, errors.New("unable to read supported versions extension data")
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}
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supportedVersions := []uint16{}
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for !versList.Empty() {
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var vers uint16
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if !versList.ReadUint16(&vers) {
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return nil, errors.New("unable to read supported versions extension data")
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}
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supportedVersions = append(supportedVersions, unGREASEUint16(vers))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &SupportedVersionsExtension{supportedVersions})
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// If SupportedVersionsExtension is present, use that instead of record+handshake versions
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clientHelloSpec.TLSVersMin = 0
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clientHelloSpec.TLSVersMax = 0
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case extensionKeyShare:
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// RFC 8446, Section 4.2.8
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var clientShares cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&clientShares) {
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return nil, errors.New("unable to read key share extension data")
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}
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keyShares := []KeyShare{}
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for !clientShares.Empty() {
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var ks KeyShare
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var group uint16
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if !clientShares.ReadUint16(&group) ||
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!readUint16LengthPrefixed(&clientShares, &ks.Data) ||
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len(ks.Data) == 0 {
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return nil, errors.New("unable to read key share extension data")
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}
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ks.Group = CurveID(unGREASEUint16(group))
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// if not GREASE, key share data will be discarded as it should
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// be generated per connection
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if ks.Group != GREASE_PLACEHOLDER {
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ks.Data = nil
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}
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keyShares = append(keyShares, ks)
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &KeyShareExtension{keyShares})
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case extensionPSKModes:
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// RFC 8446, Section 4.2.9
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// TODO: PSK Modes have their own form of GREASE-ing which is not currently implemented
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// the current functionality will NOT re-GREASE/re-randomize these values when using a fingerprinted spec
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// https://github.com/refraction-networking/utls/pull/58#discussion_r522354105
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// https://tools.ietf.org/html/draft-ietf-tls-grease-01#section-2
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pskModes := []uint8{}
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if !readUint8LengthPrefixed(&extData, &pskModes) {
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return nil, errors.New("unable to read PSK extension data")
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &PSKKeyExchangeModesExtension{pskModes})
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case utlsExtensionExtendedMasterSecret:
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// https://tools.ietf.org/html/rfc7627
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &UtlsExtendedMasterSecretExtension{})
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case utlsExtensionPadding:
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle})
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case utlsExtensionCompressCertificate:
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methods := []CertCompressionAlgo{}
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methodsRaw := new(cryptobyte.String)
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if !extData.ReadUint8LengthPrefixed(methodsRaw) {
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return nil, errors.New("unable to read cert compression algorithms extension data")
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}
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for !methodsRaw.Empty() {
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var method uint16
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if !methodsRaw.ReadUint16(&method) {
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return nil, errors.New("unable to read cert compression algorithms extension data")
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}
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methods = append(methods, CertCompressionAlgo(method))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &UtlsCompressCertExtension{methods})
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case fakeExtensionChannelID:
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &FakeChannelIDExtension{})
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case fakeOldExtensionChannelID:
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &FakeChannelIDExtension{true})
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case fakeExtensionTokenBinding:
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var tokenBindingExt FakeTokenBindingExtension
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var keyParameters cryptobyte.String
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if !extData.ReadUint8(&tokenBindingExt.MajorVersion) ||
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!extData.ReadUint8(&tokenBindingExt.MinorVersion) ||
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!extData.ReadUint8LengthPrefixed(&keyParameters) {
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return nil, errors.New("unable to read token binding extension data")
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}
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tokenBindingExt.KeyParameters = keyParameters
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &tokenBindingExt)
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case utlsExtensionApplicationSettings:
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// Similar to ALPN (RFC 7301, Section 3.1):
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// https://datatracker.ietf.org/doc/html/draft-vvv-tls-alps#section-3
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var protoList cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&protoList) || protoList.Empty() {
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return nil, errors.New("unable to read ALPS extension data")
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}
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supportedProtocols := []string{}
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for !protoList.Empty() {
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var proto cryptobyte.String
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if !protoList.ReadUint8LengthPrefixed(&proto) || proto.Empty() {
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return nil, errors.New("unable to read ALPS extension data")
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}
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supportedProtocols = append(supportedProtocols, string(proto))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &ApplicationSettingsExtension{supportedProtocols})
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case fakeRecordSizeLimit:
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recordSizeExt := new(FakeRecordSizeLimitExtension)
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if !extData.ReadUint16(&recordSizeExt.Limit) {
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return nil, errors.New("unable to read record size limit extension data")
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, recordSizeExt)
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case fakeExtensionDelegatedCredentials:
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//https://datatracker.ietf.org/doc/html/draft-ietf-tls-subcerts-15#section-4.1.1
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var supportedAlgs cryptobyte.String
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if !extData.ReadUint16LengthPrefixed(&supportedAlgs) || supportedAlgs.Empty() {
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return nil, errors.New("unable to read signature algorithms extension data")
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}
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supportedSignatureAlgorithms := []SignatureScheme{}
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for !supportedAlgs.Empty() {
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var sigAndAlg uint16
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if !supportedAlgs.ReadUint16(&sigAndAlg) {
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return nil, errors.New("unable to read signature algorithms extension data")
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}
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supportedSignatureAlgorithms = append(
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supportedSignatureAlgorithms, SignatureScheme(sigAndAlg))
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}
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &FakeDelegatedCredentialsExtension{supportedSignatureAlgorithms})
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case extensionPreSharedKey:
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// RFC 8446, Section 4.2.11
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if f.KeepPSK {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &GenericExtension{extension, extData})
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} else {
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return nil, errors.New("unsupported extension PreSharedKey")
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}
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case extensionCookie:
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// RFC 8446, Section 4.2.2
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if f.AllowBluntMimicry {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &GenericExtension{extension, extData})
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} else {
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return nil, errors.New("unsupported extension Cookie")
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}
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case extensionEarlyData:
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// RFC 8446, Section 4.2.10
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if f.AllowBluntMimicry {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &GenericExtension{extension, extData})
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} else {
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return nil, errors.New("unsupported extension EarlyData")
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}
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default:
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if isGREASEUint16(extension) {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &UtlsGREASEExtension{unGREASEUint16(extension), extData})
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} else if f.AllowBluntMimicry {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &GenericExtension{extension, extData})
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} else {
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return nil, fmt.Errorf("unsupported extension %d", extension)
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}
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continue
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}
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err = clientHelloSpec.ReadTLSExtensions(extensions, f.AllowBluntMimicry)
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if err != nil {
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return nil, err
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}
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if f.AlwaysAddPadding {
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alreadyHasPadding := false
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for _, ext := range clientHelloSpec.Extensions {
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if _, ok := ext.(*UtlsPaddingExtension); ok {
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alreadyHasPadding = true
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break
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}
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}
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if !alreadyHasPadding {
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clientHelloSpec.Extensions = append(clientHelloSpec.Extensions, &UtlsPaddingExtension{GetPaddingLen: BoringPaddingStyle})
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}
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clientHelloSpec.AlwaysAddPadding()
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}
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return clientHelloSpec, nil
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