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64 lines
1.5 KiB
Go
64 lines
1.5 KiB
Go
package shadowsocks
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import (
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"crypto/md5"
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"hash/crc32"
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"io"
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"math/rand"
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"net"
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E "github.com/sagernet/sing/common/exceptions"
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M "github.com/sagernet/sing/common/metadata"
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N "github.com/sagernet/sing/common/network"
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)
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var (
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ErrBadKey = E.New("bad key")
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ErrMissingPassword = E.New("missing password")
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)
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type Method interface {
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Name() string
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KeyLength() int
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DialConn(conn net.Conn, destination M.Socksaddr) (net.Conn, error)
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DialEarlyConn(conn net.Conn, destination M.Socksaddr) net.Conn
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DialPacketConn(conn net.Conn) N.NetPacketConn
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}
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func Key(password []byte, keySize int) []byte {
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const md5Len = 16
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cnt := (keySize-1)/md5Len + 1
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m := make([]byte, cnt*md5Len)
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sum := md5.Sum(password)
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copy(m, sum[:])
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// Repeatedly call md5 until bytes generated is enough.
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// Each call to md5 uses data: prev md5 sum + password.
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d := make([]byte, md5Len+len(password))
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start := 0
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for i := 1; i < cnt; i++ {
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start += md5Len
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copy(d, m[start-md5Len:start])
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copy(d[md5Len:], password)
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sum = md5.Sum(d)
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copy(m[start:], sum[:])
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}
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return m[:keySize]
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}
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type ReducedEntropyReader struct {
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io.Reader
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}
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func (r *ReducedEntropyReader) Read(p []byte) (n int, err error) {
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n, err = r.Reader.Read(p)
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if n > 6 {
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const charSet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~\\\""
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seed := rand.New(rand.NewSource(int64(crc32.ChecksumIEEE(p[:6]))))
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for i := range p[:6] {
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p[i] = charSet[seed.Intn(len(charSet))]
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}
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}
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return
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}
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