370 lines
8.1 KiB
Go
370 lines
8.1 KiB
Go
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// Copyright 2018 The GoPacket Authors. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the LICENSE file in the root of the source
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// tree.
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// Most of this content was extracted from go tls package
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package etls
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type handshakeMessage interface {
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unmarshal([]byte) bool
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}
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type clientHelloMsg struct {
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raw []byte
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extensions map[Extension]uint16
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AllExtensions []uint16
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Vers uint16
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random []byte
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sessionId []byte
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CipherSuites []uint16
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compressionMethods []uint8
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nextProtoNeg bool
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serverName string
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ocspStapling bool
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scts bool
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SupportedCurves []CurveID
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SupportedPoints []uint8
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ticketSupported bool
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sessionTicket []uint8
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supportedSignatureAlgorithms []SignatureScheme
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secureRenegotiation []byte
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secureRenegotiationSupported bool
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alpnProtocols []string
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}
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func (m *clientHelloMsg) unmarshal(data []byte) bool {
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if len(data) < 42 {
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return false
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}
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m.raw = data
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m.Vers = uint16(data[4])<<8 | uint16(data[5])
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m.random = data[6:38]
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sessionIdLen := int(data[38])
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if sessionIdLen > 32 || len(data) < 39+sessionIdLen {
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return false
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}
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m.sessionId = data[39 : 39+sessionIdLen]
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data = data[39+sessionIdLen:]
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if len(data) < 2 {
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return false
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}
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// cipherSuiteLen is the number of bytes of cipher suite numbers. Since
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// they are uint16s, the number must be even.
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cipherSuiteLen := int(data[0])<<8 | int(data[1])
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if cipherSuiteLen%2 == 1 || len(data) < 2+cipherSuiteLen {
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return false
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}
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numCipherSuites := cipherSuiteLen / 2
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m.CipherSuites = make([]uint16, numCipherSuites)
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for i := 0; i < numCipherSuites; i++ {
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m.CipherSuites[i] = uint16(data[2+2*i])<<8 | uint16(data[3+2*i])
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if m.CipherSuites[i] == scsvRenegotiation {
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m.secureRenegotiationSupported = true
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}
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}
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data = data[2+cipherSuiteLen:]
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if len(data) < 1 {
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return false
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}
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compressionMethodsLen := int(data[0])
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if len(data) < 1+compressionMethodsLen {
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return false
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}
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m.compressionMethods = data[1 : 1+compressionMethodsLen]
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data = data[1+compressionMethodsLen:]
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m.nextProtoNeg = false
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m.serverName = ""
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m.ocspStapling = false
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m.ticketSupported = false
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m.sessionTicket = nil
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m.supportedSignatureAlgorithms = nil
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m.alpnProtocols = nil
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m.scts = false
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if len(data) == 0 {
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// ClientHello is optionally followed by extension data
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return true
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}
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if len(data) < 2 {
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return false
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}
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// We parse extensions as their needed for ja3
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extensionsLength := int(data[0])<<8 | int(data[1])
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data = data[2:]
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m.extensions = make(map[Extension]uint16)
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if extensionsLength != len(data) {
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return false
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}
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for len(data) != 0 {
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if len(data) < 4 {
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return false
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}
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extension := uint16(data[0])<<8 | uint16(data[1])
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length := int(data[2])<<8 | int(data[3])
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data = data[4:]
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m.AllExtensions = append(m.AllExtensions, uint16(extension))
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if len(data) < length {
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return false
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}
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switch extension {
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case extensionSupportedCurves:
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// https://tools.ietf.org/html/rfc4492#section-5.5.1
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if length < 2 {
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return false
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}
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l := int(data[0])<<8 | int(data[1])
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if l%2 == 1 || length != l+2 {
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return false
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}
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numCurves := l / 2
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m.SupportedCurves = make([]CurveID, numCurves)
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d := data[2:]
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for i := 0; i < numCurves; i++ {
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m.SupportedCurves[i] = CurveID(d[0])<<8 | CurveID(d[1])
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d = d[2:]
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}
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case extensionSupportedPoints:
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// https://tools.ietf.org/html/rfc4492#section-5.5.2
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if length < 1 {
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return false
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}
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l := int(data[0])
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if length != l+1 {
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return false
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}
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m.SupportedPoints = make([]uint8, l)
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copy(m.SupportedPoints, data[1:])
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}
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data = data[length:]
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}
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return true
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}
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type serverHelloMsg struct {
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raw []byte
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extensions map[Extension]uint16
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AllExtensions []uint16
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Vers uint16
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random []byte
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sessionId []byte
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CipherSuite uint16
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compressionMethod uint8
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nextProtoNeg bool
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nextProtos []string
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ocspStapling bool
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scts [][]byte
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ticketSupported bool
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secureRenegotiation []byte
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secureRenegotiationSupported bool
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alpnProtocol string
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}
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func (m *serverHelloMsg) unmarshal(data []byte) bool {
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if len(data) < 42 {
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return false
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}
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m.raw = data
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m.Vers = uint16(data[4])<<8 | uint16(data[5])
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m.random = data[6:38]
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sessionIdLen := int(data[38])
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if sessionIdLen > 32 || len(data) < 39+sessionIdLen {
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return false
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}
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m.sessionId = data[39 : 39+sessionIdLen]
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data = data[39+sessionIdLen:]
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if len(data) < 3 {
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return false
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}
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m.CipherSuite = uint16(data[0])<<8 | uint16(data[1])
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m.compressionMethod = data[2]
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data = data[3:]
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m.nextProtoNeg = false
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m.nextProtos = nil
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m.ocspStapling = false
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m.scts = nil
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m.ticketSupported = false
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m.alpnProtocol = ""
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if len(data) == 0 {
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// ServerHello is optionally followed by extension data
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return true
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}
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if len(data) < 2 {
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return false
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}
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// Import Extension code needed for ja3s
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extensionsLength := int(data[0])<<8 | int(data[1])
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data = data[2:]
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m.extensions = make(map[Extension]uint16)
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if len(data) != extensionsLength {
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return false
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}
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for len(data) != 0 {
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if len(data) < 4 {
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return false
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}
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extension := uint16(data[0])<<8 | uint16(data[1])
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length := int(data[2])<<8 | int(data[3])
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data = data[4:]
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m.AllExtensions = append(m.AllExtensions, uint16(extension))
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if len(data) < length {
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return false
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}
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switch extension {
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case extensionNextProtoNeg:
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m.nextProtoNeg = true
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d := data[:length]
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for len(d) > 0 {
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l := int(d[0])
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d = d[1:]
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if l == 0 || l > len(d) {
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return false
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}
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m.nextProtos = append(m.nextProtos, string(d[:l]))
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d = d[l:]
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}
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case extensionStatusRequest:
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if length > 0 {
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return false
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}
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m.ocspStapling = true
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case extensionSessionTicket:
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if length > 0 {
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return false
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}
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m.ticketSupported = true
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case extensionRenegotiationInfo:
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if length == 0 {
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return false
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}
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d := data[:length]
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l := int(d[0])
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d = d[1:]
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if l != len(d) {
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return false
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}
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m.secureRenegotiation = d
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m.secureRenegotiationSupported = true
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case extensionALPN:
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d := data[:length]
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if len(d) < 3 {
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return false
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}
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l := int(d[0])<<8 | int(d[1])
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if l != len(d)-2 {
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return false
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}
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d = d[2:]
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l = int(d[0])
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if l != len(d)-1 {
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return false
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}
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d = d[1:]
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if len(d) == 0 {
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// ALPN protocols must not be empty.
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return false
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}
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m.alpnProtocol = string(d)
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case extensionSCT:
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d := data[:length]
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if len(d) < 2 {
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return false
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}
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l := int(d[0])<<8 | int(d[1])
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d = d[2:]
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if len(d) != l || l == 0 {
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return false
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}
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m.scts = make([][]byte, 0, 3)
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for len(d) != 0 {
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if len(d) < 2 {
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return false
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}
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sctLen := int(d[0])<<8 | int(d[1])
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d = d[2:]
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if sctLen == 0 || len(d) < sctLen {
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return false
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}
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m.scts = append(m.scts, d[:sctLen])
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d = d[sctLen:]
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}
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}
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data = data[length:]
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}
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return true
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}
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type certificateMsg struct {
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raw []byte
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Certificates [][]byte
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}
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func (m *certificateMsg) unmarshal(data []byte) bool {
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if len(data) < 7 {
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return false
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}
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m.raw = data
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certsLen := uint32(data[4])<<16 | uint32(data[5])<<8 | uint32(data[6])
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if uint32(len(data)) != certsLen+7 {
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return false
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}
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numCerts := 0
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d := data[7:]
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for certsLen > 0 {
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if len(d) < 4 {
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return false
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}
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certLen := uint32(d[0])<<16 | uint32(d[1])<<8 | uint32(d[2])
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if uint32(len(d)) < 3+certLen {
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return false
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}
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d = d[3+certLen:]
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certsLen -= 3 + certLen
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numCerts++
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}
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m.Certificates = make([][]byte, numCerts)
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d = data[7:]
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for i := 0; i < numCerts; i++ {
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certLen := uint32(d[0])<<16 | uint32(d[1])<<8 | uint32(d[2])
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m.Certificates[i] = d[3 : 3+certLen]
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d = d[3+certLen:]
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}
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return true
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}
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