github.com/mdempsky/go@v0.0.0-20151201204031-5dd372bd1e70/src/crypto/tls/cipher_suites.go (about) 1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package tls 6 7 import ( 8 "crypto/aes" 9 "crypto/cipher" 10 "crypto/des" 11 "crypto/hmac" 12 "crypto/rc4" 13 "crypto/sha1" 14 "crypto/x509" 15 "hash" 16 ) 17 18 // a keyAgreement implements the client and server side of a TLS key agreement 19 // protocol by generating and processing key exchange messages. 20 type keyAgreement interface { 21 // On the server side, the first two methods are called in order. 22 23 // In the case that the key agreement protocol doesn't use a 24 // ServerKeyExchange message, generateServerKeyExchange can return nil, 25 // nil. 26 generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error) 27 processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error) 28 29 // On the client side, the next two methods are called in order. 30 31 // This method may not be called if the server doesn't send a 32 // ServerKeyExchange message. 33 processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error 34 generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error) 35 } 36 37 const ( 38 // suiteECDH indicates that the cipher suite involves elliptic curve 39 // Diffie-Hellman. This means that it should only be selected when the 40 // client indicates that it supports ECC with a curve and point format 41 // that we're happy with. 42 suiteECDHE = 1 << iota 43 // suiteECDSA indicates that the cipher suite involves an ECDSA 44 // signature and therefore may only be selected when the server's 45 // certificate is ECDSA. If this is not set then the cipher suite is 46 // RSA based. 47 suiteECDSA 48 // suiteTLS12 indicates that the cipher suite should only be advertised 49 // and accepted when using TLS 1.2. 50 suiteTLS12 51 // suiteSHA384 indicates that the cipher suite uses SHA384 as the 52 // handshake hash. 53 suiteSHA384 54 // suiteDefaultOff indicates that this cipher suite is not included by 55 // default. 56 suiteDefaultOff 57 ) 58 59 // A cipherSuite is a specific combination of key agreement, cipher and MAC 60 // function. All cipher suites currently assume RSA key agreement. 61 type cipherSuite struct { 62 id uint16 63 // the lengths, in bytes, of the key material needed for each component. 64 keyLen int 65 macLen int 66 ivLen int 67 ka func(version uint16) keyAgreement 68 // flags is a bitmask of the suite* values, above. 69 flags int 70 cipher func(key, iv []byte, isRead bool) interface{} 71 mac func(version uint16, macKey []byte) macFunction 72 aead func(key, fixedNonce []byte) cipher.AEAD 73 } 74 75 var cipherSuites = []*cipherSuite{ 76 // Ciphersuite order is chosen so that ECDHE comes before plain RSA 77 // and RC4 comes before AES (because of the Lucky13 attack). 78 {TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM}, 79 {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadAESGCM}, 80 {TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM}, 81 {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM}, 82 {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE | suiteDefaultOff, cipherRC4, macSHA1, nil}, 83 {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteDefaultOff, cipherRC4, macSHA1, nil}, 84 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil}, 85 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil}, 86 {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil}, 87 {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil}, 88 {TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM}, 89 {TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM}, 90 {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, suiteDefaultOff, cipherRC4, macSHA1, nil}, 91 {TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil}, 92 {TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil}, 93 {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil}, 94 {TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil}, 95 } 96 97 func cipherRC4(key, iv []byte, isRead bool) interface{} { 98 cipher, _ := rc4.NewCipher(key) 99 return cipher 100 } 101 102 func cipher3DES(key, iv []byte, isRead bool) interface{} { 103 block, _ := des.NewTripleDESCipher(key) 104 if isRead { 105 return cipher.NewCBCDecrypter(block, iv) 106 } 107 return cipher.NewCBCEncrypter(block, iv) 108 } 109 110 func cipherAES(key, iv []byte, isRead bool) interface{} { 111 block, _ := aes.NewCipher(key) 112 if isRead { 113 return cipher.NewCBCDecrypter(block, iv) 114 } 115 return cipher.NewCBCEncrypter(block, iv) 116 } 117 118 // macSHA1 returns a macFunction for the given protocol version. 119 func macSHA1(version uint16, key []byte) macFunction { 120 if version == VersionSSL30 { 121 mac := ssl30MAC{ 122 h: sha1.New(), 123 key: make([]byte, len(key)), 124 } 125 copy(mac.key, key) 126 return mac 127 } 128 return tls10MAC{hmac.New(sha1.New, key)} 129 } 130 131 type macFunction interface { 132 Size() int 133 MAC(digestBuf, seq, header, data []byte) []byte 134 } 135 136 // fixedNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to 137 // each call. 138 type fixedNonceAEAD struct { 139 // sealNonce and openNonce are buffers where the larger nonce will be 140 // constructed. Since a seal and open operation may be running 141 // concurrently, there is a separate buffer for each. 142 sealNonce, openNonce []byte 143 aead cipher.AEAD 144 } 145 146 func (f *fixedNonceAEAD) NonceSize() int { return 8 } 147 func (f *fixedNonceAEAD) Overhead() int { return f.aead.Overhead() } 148 149 func (f *fixedNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte { 150 copy(f.sealNonce[len(f.sealNonce)-8:], nonce) 151 return f.aead.Seal(out, f.sealNonce, plaintext, additionalData) 152 } 153 154 func (f *fixedNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) { 155 copy(f.openNonce[len(f.openNonce)-8:], nonce) 156 return f.aead.Open(out, f.openNonce, plaintext, additionalData) 157 } 158 159 func aeadAESGCM(key, fixedNonce []byte) cipher.AEAD { 160 aes, err := aes.NewCipher(key) 161 if err != nil { 162 panic(err) 163 } 164 aead, err := cipher.NewGCM(aes) 165 if err != nil { 166 panic(err) 167 } 168 169 nonce1, nonce2 := make([]byte, 12), make([]byte, 12) 170 copy(nonce1, fixedNonce) 171 copy(nonce2, fixedNonce) 172 173 return &fixedNonceAEAD{nonce1, nonce2, aead} 174 } 175 176 // ssl30MAC implements the SSLv3 MAC function, as defined in 177 // www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1 178 type ssl30MAC struct { 179 h hash.Hash 180 key []byte 181 } 182 183 func (s ssl30MAC) Size() int { 184 return s.h.Size() 185 } 186 187 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} 188 189 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} 190 191 func (s ssl30MAC) MAC(digestBuf, seq, header, data []byte) []byte { 192 padLength := 48 193 if s.h.Size() == 20 { 194 padLength = 40 195 } 196 197 s.h.Reset() 198 s.h.Write(s.key) 199 s.h.Write(ssl30Pad1[:padLength]) 200 s.h.Write(seq) 201 s.h.Write(header[:1]) 202 s.h.Write(header[3:5]) 203 s.h.Write(data) 204 digestBuf = s.h.Sum(digestBuf[:0]) 205 206 s.h.Reset() 207 s.h.Write(s.key) 208 s.h.Write(ssl30Pad2[:padLength]) 209 s.h.Write(digestBuf) 210 return s.h.Sum(digestBuf[:0]) 211 } 212 213 // tls10MAC implements the TLS 1.0 MAC function. RFC 2246, section 6.2.3. 214 type tls10MAC struct { 215 h hash.Hash 216 } 217 218 func (s tls10MAC) Size() int { 219 return s.h.Size() 220 } 221 222 func (s tls10MAC) MAC(digestBuf, seq, header, data []byte) []byte { 223 s.h.Reset() 224 s.h.Write(seq) 225 s.h.Write(header) 226 s.h.Write(data) 227 return s.h.Sum(digestBuf[:0]) 228 } 229 230 func rsaKA(version uint16) keyAgreement { 231 return rsaKeyAgreement{} 232 } 233 234 func ecdheECDSAKA(version uint16) keyAgreement { 235 return &ecdheKeyAgreement{ 236 sigType: signatureECDSA, 237 version: version, 238 } 239 } 240 241 func ecdheRSAKA(version uint16) keyAgreement { 242 return &ecdheKeyAgreement{ 243 sigType: signatureRSA, 244 version: version, 245 } 246 } 247 248 // mutualCipherSuite returns a cipherSuite given a list of supported 249 // ciphersuites and the id requested by the peer. 250 func mutualCipherSuite(have []uint16, want uint16) *cipherSuite { 251 for _, id := range have { 252 if id == want { 253 for _, suite := range cipherSuites { 254 if suite.id == want { 255 return suite 256 } 257 } 258 return nil 259 } 260 } 261 return nil 262 } 263 264 // A list of the possible cipher suite ids. Taken from 265 // http://www.iana.org/assignments/tls-parameters/tls-parameters.xml 266 const ( 267 TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005 268 TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a 269 TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f 270 TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035 271 TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c 272 TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d 273 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007 274 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009 275 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a 276 TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011 277 TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012 278 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013 279 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014 280 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f 281 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b 282 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030 283 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c 284 285 // TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator 286 // that the client is doing version fallback. See 287 // https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00. 288 TLS_FALLBACK_SCSV uint16 = 0x5600 289 )