mirror of
https://github.com/MetaCubeX/mihomo.git
synced 2024-08-26 03:42:32 +00:00
310 lines
8 KiB
Go
310 lines
8 KiB
Go
package protocol
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import (
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"bytes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/rc4"
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"encoding/base64"
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"encoding/binary"
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"net"
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"strconv"
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"strings"
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"github.com/Dreamacro/clash/common/pool"
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"github.com/Dreamacro/clash/log"
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"github.com/Dreamacro/clash/transport/ssr/tools"
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"github.com/Dreamacro/go-shadowsocks2/core"
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)
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func init() {
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register("auth_chain_a", newAuthChainA, 4)
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}
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type randDataLengthMethod func(int, []byte, *tools.XorShift128Plus) int
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type authChainA struct {
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*Base
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*authData
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*userData
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iv []byte
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salt string
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hasSentHeader bool
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rawTrans bool
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lastClientHash []byte
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lastServerHash []byte
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encrypter cipher.Stream
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decrypter cipher.Stream
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randomClient tools.XorShift128Plus
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randomServer tools.XorShift128Plus
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randDataLength randDataLengthMethod
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packID uint32
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recvID uint32
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}
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func newAuthChainA(b *Base) Protocol {
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a := &authChainA{
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Base: b,
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authData: &authData{},
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userData: &userData{},
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salt: "auth_chain_a",
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}
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a.initUserData()
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return a
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}
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func (a *authChainA) initUserData() {
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params := strings.Split(a.Param, ":")
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if len(params) > 1 {
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if userID, err := strconv.ParseUint(params[0], 10, 32); err == nil {
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binary.LittleEndian.PutUint32(a.userID[:], uint32(userID))
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a.userKey = []byte(params[1])
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} else {
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log.Warnln("Wrong protocol-param for %s, only digits are expected before ':'", a.salt)
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}
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}
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if len(a.userKey) == 0 {
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a.userKey = a.Key
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rand.Read(a.userID[:])
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}
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}
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func (a *authChainA) StreamConn(c net.Conn, iv []byte) net.Conn {
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p := &authChainA{
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Base: a.Base,
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authData: a.next(),
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userData: a.userData,
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salt: a.salt,
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packID: 1,
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recvID: 1,
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}
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p.iv = iv
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p.randDataLength = p.getRandLength
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return &Conn{Conn: c, Protocol: p}
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}
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func (a *authChainA) PacketConn(c net.PacketConn) net.PacketConn {
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p := &authChainA{
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Base: a.Base,
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salt: a.salt,
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userData: a.userData,
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}
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return &PacketConn{PacketConn: c, Protocol: p}
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}
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func (a *authChainA) Decode(dst, src *bytes.Buffer) error {
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if a.rawTrans {
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dst.ReadFrom(src)
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return nil
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}
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for src.Len() > 4 {
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macKey := pool.Get(len(a.userKey) + 4)
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defer pool.Put(macKey)
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copy(macKey, a.userKey)
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binary.LittleEndian.PutUint32(macKey[len(a.userKey):], a.recvID)
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dataLength := int(binary.LittleEndian.Uint16(src.Bytes()[:2]) ^ binary.LittleEndian.Uint16(a.lastServerHash[14:16]))
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randDataLength := a.randDataLength(dataLength, a.lastServerHash, &a.randomServer)
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length := dataLength + randDataLength
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if length >= 4096 {
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a.rawTrans = true
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src.Reset()
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return errAuthChainLengthError
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}
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if 4+length > src.Len() {
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break
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}
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serverHash := tools.HmacMD5(macKey, src.Bytes()[:length+2])
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if !bytes.Equal(serverHash[:2], src.Bytes()[length+2:length+4]) {
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a.rawTrans = true
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src.Reset()
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return errAuthChainChksumError
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}
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a.lastServerHash = serverHash
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pos := 2
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if dataLength > 0 && randDataLength > 0 {
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pos += getRandStartPos(randDataLength, &a.randomServer)
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}
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wantedData := src.Bytes()[pos : pos+dataLength]
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a.decrypter.XORKeyStream(wantedData, wantedData)
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if a.recvID == 1 {
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dst.Write(wantedData[2:])
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} else {
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dst.Write(wantedData)
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}
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a.recvID++
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src.Next(length + 4)
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}
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return nil
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}
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func (a *authChainA) Encode(buf *bytes.Buffer, b []byte) error {
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if !a.hasSentHeader {
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dataLength := getDataLength(b)
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a.packAuthData(buf, b[:dataLength])
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b = b[dataLength:]
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a.hasSentHeader = true
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}
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for len(b) > 2800 {
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a.packData(buf, b[:2800])
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b = b[2800:]
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}
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if len(b) > 0 {
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a.packData(buf, b)
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}
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return nil
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}
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func (a *authChainA) DecodePacket(b []byte) ([]byte, error) {
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if len(b) < 9 {
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return nil, errAuthChainLengthError
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}
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if !bytes.Equal(tools.HmacMD5(a.userKey, b[:len(b)-1])[:1], b[len(b)-1:]) {
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return nil, errAuthChainChksumError
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}
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md5Data := tools.HmacMD5(a.Key, b[len(b)-8:len(b)-1])
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randDataLength := udpGetRandLength(md5Data, &a.randomServer)
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key := core.Kdf(base64.StdEncoding.EncodeToString(a.userKey)+base64.StdEncoding.EncodeToString(md5Data), 16)
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rc4Cipher, err := rc4.NewCipher(key)
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if err != nil {
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return nil, err
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}
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wantedData := b[:len(b)-8-randDataLength]
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rc4Cipher.XORKeyStream(wantedData, wantedData)
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return wantedData, nil
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}
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func (a *authChainA) EncodePacket(buf *bytes.Buffer, b []byte) error {
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authData := pool.Get(3)
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defer pool.Put(authData)
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rand.Read(authData)
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md5Data := tools.HmacMD5(a.Key, authData)
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randDataLength := udpGetRandLength(md5Data, &a.randomClient)
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key := core.Kdf(base64.StdEncoding.EncodeToString(a.userKey)+base64.StdEncoding.EncodeToString(md5Data), 16)
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rc4Cipher, err := rc4.NewCipher(key)
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if err != nil {
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return err
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}
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rc4Cipher.XORKeyStream(b, b)
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buf.Write(b)
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tools.AppendRandBytes(buf, randDataLength)
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buf.Write(authData)
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binary.Write(buf, binary.LittleEndian, binary.LittleEndian.Uint32(a.userID[:])^binary.LittleEndian.Uint32(md5Data[:4]))
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buf.Write(tools.HmacMD5(a.userKey, buf.Bytes())[:1])
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return nil
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}
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func (a *authChainA) packAuthData(poolBuf *bytes.Buffer, data []byte) {
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/*
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dataLength := len(data)
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12: checkHead(4) and hmac of checkHead(8)
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4: uint32 LittleEndian uid (uid = userID ^ last client hash)
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16: encrypted data of authdata(12), uint16 LittleEndian overhead(2) and uint16 LittleEndian number zero(2)
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4: last server hash(4)
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packedAuthDataLength := 12 + 4 + 16 + 4 + dataLength
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*/
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macKey := pool.Get(len(a.iv) + len(a.Key))
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defer pool.Put(macKey)
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copy(macKey, a.iv)
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copy(macKey[len(a.iv):], a.Key)
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// check head
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tools.AppendRandBytes(poolBuf, 4)
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a.lastClientHash = tools.HmacMD5(macKey, poolBuf.Bytes())
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a.initRC4Cipher()
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poolBuf.Write(a.lastClientHash[:8])
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// uid
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binary.Write(poolBuf, binary.LittleEndian, binary.LittleEndian.Uint32(a.userID[:])^binary.LittleEndian.Uint32(a.lastClientHash[8:12]))
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// encrypted data
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err := a.putEncryptedData(poolBuf, a.userKey, [2]int{a.Overhead, 0}, a.salt)
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if err != nil {
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poolBuf.Reset()
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return
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}
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// last server hash
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a.lastServerHash = tools.HmacMD5(a.userKey, poolBuf.Bytes()[12:])
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poolBuf.Write(a.lastServerHash[:4])
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// packed data
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a.packData(poolBuf, data)
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}
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func (a *authChainA) packData(poolBuf *bytes.Buffer, data []byte) {
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a.encrypter.XORKeyStream(data, data)
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macKey := pool.Get(len(a.userKey) + 4)
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defer pool.Put(macKey)
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copy(macKey, a.userKey)
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binary.LittleEndian.PutUint32(macKey[len(a.userKey):], a.packID)
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a.packID++
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length := uint16(len(data)) ^ binary.LittleEndian.Uint16(a.lastClientHash[14:16])
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originalLength := poolBuf.Len()
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binary.Write(poolBuf, binary.LittleEndian, length)
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a.putMixedRandDataAndData(poolBuf, data)
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a.lastClientHash = tools.HmacMD5(macKey, poolBuf.Bytes()[originalLength:])
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poolBuf.Write(a.lastClientHash[:2])
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}
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func (a *authChainA) putMixedRandDataAndData(poolBuf *bytes.Buffer, data []byte) {
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randDataLength := a.randDataLength(len(data), a.lastClientHash, &a.randomClient)
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if len(data) == 0 {
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tools.AppendRandBytes(poolBuf, randDataLength)
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return
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}
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if randDataLength > 0 {
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startPos := getRandStartPos(randDataLength, &a.randomClient)
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tools.AppendRandBytes(poolBuf, startPos)
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poolBuf.Write(data)
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tools.AppendRandBytes(poolBuf, randDataLength-startPos)
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return
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}
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poolBuf.Write(data)
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}
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func getRandStartPos(length int, random *tools.XorShift128Plus) int {
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if length == 0 {
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return 0
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}
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return int(random.Next()%8589934609) % length
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}
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func (a *authChainA) getRandLength(length int, lastHash []byte, random *tools.XorShift128Plus) int {
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if length > 1440 {
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return 0
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}
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random.InitFromBinAndLength(lastHash, length)
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if length > 1300 {
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return int(random.Next() % 31)
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}
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if length > 900 {
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return int(random.Next() % 127)
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}
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if length > 400 {
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return int(random.Next() % 521)
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}
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return int(random.Next() % 1021)
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}
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func (a *authChainA) initRC4Cipher() {
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key := core.Kdf(base64.StdEncoding.EncodeToString(a.userKey)+base64.StdEncoding.EncodeToString(a.lastClientHash), 16)
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a.encrypter, _ = rc4.NewCipher(key)
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a.decrypter, _ = rc4.NewCipher(key)
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}
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func udpGetRandLength(lastHash []byte, random *tools.XorShift128Plus) int {
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random.InitFromBin(lastHash)
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return int(random.Next() % 127)
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}
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