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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/aes"
- "crypto/cipher"
- "crypto/des"
- "crypto/hmac"
- "crypto/rc4"
- "crypto/sha1"
- "crypto/x509"
- "hash"
- )
-
- // a keyAgreement implements the client and server side of a TLS 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)
- }
-
- // A cipherSuite is a specific combination of key agreement, cipher and MAC
- // function. All cipher suites currently assume RSA key agreement.
- 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() keyAgreement
- // If elliptic is set, a server will only consider this ciphersuite if
- // the ClientHello indicated that the client supports an elliptic curve
- // and point format that we can handle.
- elliptic bool
- cipher func(key, iv []byte, isRead bool) interface{}
- mac func(version uint16, macKey []byte) macFunction
- }
-
- var cipherSuites = []*cipherSuite{
- {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, false, cipherRC4, macSHA1},
- {TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, false, cipher3DES, macSHA1},
- {TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, false, cipherAES, macSHA1},
- {TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, false, cipherAES, macSHA1},
- {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, true, cipherRC4, macSHA1},
- {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, true, cipher3DES, macSHA1},
- {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, true, cipherAES, macSHA1},
- {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, true, cipherAES, macSHA1},
- }
-
- func cipherRC4(key, iv []byte, isRead bool) interface{} {
- cipher, _ := rc4.NewCipher(key)
- return cipher
- }
-
- func cipher3DES(key, iv []byte, isRead bool) interface{} {
- block, _ := des.NewTripleDESCipher(key)
- if isRead {
- return cipher.NewCBCDecrypter(block, iv)
- }
- return cipher.NewCBCEncrypter(block, iv)
- }
-
- func cipherAES(key, iv []byte, isRead bool) interface{} {
- block, _ := aes.NewCipher(key)
- if isRead {
- return cipher.NewCBCDecrypter(block, iv)
- }
- return cipher.NewCBCEncrypter(block, iv)
- }
-
- // macSHA1 returns a macFunction for the given protocol version.
- func macSHA1(version uint16, key []byte) macFunction {
- if version == VersionSSL30 {
- mac := ssl30MAC{
- h: sha1.New(),
- key: make([]byte, len(key)),
- }
- copy(mac.key, key)
- return mac
- }
- return tls10MAC{hmac.New(sha1.New, key)}
- }
-
- type macFunction interface {
- Size() int
- MAC(digestBuf, seq, header, data []byte) []byte
- }
-
- // ssl30MAC implements the SSLv3 MAC function, as defined in
- // www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1
- type ssl30MAC struct {
- h hash.Hash
- key []byte
- }
-
- func (s ssl30MAC) Size() int {
- return s.h.Size()
- }
-
- var ssl30Pad1 = [48]byte{0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36}
-
- var ssl30Pad2 = [48]byte{0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c}
-
- func (s ssl30MAC) MAC(digestBuf, seq, header, data []byte) []byte {
- padLength := 48
- if s.h.Size() == 20 {
- padLength = 40
- }
-
- s.h.Reset()
- s.h.Write(s.key)
- s.h.Write(ssl30Pad1[:padLength])
- s.h.Write(seq)
- s.h.Write(header[:1])
- s.h.Write(header[3:5])
- s.h.Write(data)
- digestBuf = s.h.Sum(digestBuf[:0])
-
- s.h.Reset()
- s.h.Write(s.key)
- s.h.Write(ssl30Pad2[:padLength])
- s.h.Write(digestBuf)
- return s.h.Sum(digestBuf[:0])
- }
-
- // tls10MAC implements the TLS 1.0 MAC function. RFC 2246, section 6.2.3.
- type tls10MAC struct {
- h hash.Hash
- }
-
- func (s tls10MAC) Size() int {
- return s.h.Size()
- }
-
- func (s tls10MAC) MAC(digestBuf, seq, header, data []byte) []byte {
- s.h.Reset()
- s.h.Write(seq)
- s.h.Write(header)
- s.h.Write(data)
- return s.h.Sum(digestBuf[:0])
- }
-
- func rsaKA() keyAgreement {
- return rsaKeyAgreement{}
- }
-
- func ecdheRSAKA() keyAgreement {
- return new(ecdheRSAKeyAgreement)
- }
-
- // 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 {
- for _, suite := range cipherSuites {
- if suite.id == want {
- return suite
- }
- }
- return nil
- }
- }
- return nil
- }
-
- // A list of the possible cipher suite ids. Taken from
- // http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
- const (
- 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_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
- )
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