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.
12 "crypto/internal/boring"
19 "golang_org/x/crypto/chacha20poly1305"
22 // a keyAgreement implements the client and server side of a TLS key agreement
23 // protocol by generating and processing key exchange messages.
24 type keyAgreement interface {
25 // On the server side, the first two methods are called in order.
27 // In the case that the key agreement protocol doesn't use a
28 // ServerKeyExchange message, generateServerKeyExchange can return nil,
30 generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
31 processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
33 // On the client side, the next two methods are called in order.
35 // This method may not be called if the server doesn't send a
36 // ServerKeyExchange message.
37 processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error
38 generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
42 // suiteECDH indicates that the cipher suite involves elliptic curve
43 // Diffie-Hellman. This means that it should only be selected when the
44 // client indicates that it supports ECC with a curve and point format
45 // that we're happy with.
46 suiteECDHE = 1 << iota
47 // suiteECDSA indicates that the cipher suite involves an ECDSA
48 // signature and therefore may only be selected when the server's
49 // certificate is ECDSA. If this is not set then the cipher suite is
52 // suiteTLS12 indicates that the cipher suite should only be advertised
53 // and accepted when using TLS 1.2.
55 // suiteSHA384 indicates that the cipher suite uses SHA384 as the
58 // suiteDefaultOff indicates that this cipher suite is not included by
63 // A cipherSuite is a specific combination of key agreement, cipher and MAC
64 // function. All cipher suites currently assume RSA key agreement.
65 type cipherSuite struct {
67 // the lengths, in bytes, of the key material needed for each component.
71 ka func(version uint16) keyAgreement
72 // flags is a bitmask of the suite* values, above.
74 cipher func(key, iv []byte, isRead bool) interface{}
75 mac func(version uint16, macKey []byte) macFunction
76 aead func(key, fixedNonce []byte) cipher.AEAD
79 var cipherSuites = []*cipherSuite{
80 // Ciphersuite order is chosen so that ECDHE comes before plain RSA and
81 // AEADs are the top preference.
82 {TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
83 {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
84 {TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
85 {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadAESGCM},
86 {TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
87 {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
88 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
89 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
90 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
91 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
92 {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
93 {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
94 {TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM},
95 {TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
96 {TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
97 {TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
98 {TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
99 {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
100 {TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil},
102 // RC4-based cipher suites are disabled by default.
103 {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, suiteDefaultOff, cipherRC4, macSHA1, nil},
104 {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE | suiteDefaultOff, cipherRC4, macSHA1, nil},
105 {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteDefaultOff, cipherRC4, macSHA1, nil},
108 func cipherRC4(key, iv []byte, isRead bool) interface{} {
109 cipher, _ := rc4.NewCipher(key)
113 func cipher3DES(key, iv []byte, isRead bool) interface{} {
114 block, _ := des.NewTripleDESCipher(key)
116 return cipher.NewCBCDecrypter(block, iv)
118 return cipher.NewCBCEncrypter(block, iv)
121 func cipherAES(key, iv []byte, isRead bool) interface{} {
122 block, _ := aes.NewCipher(key)
124 return cipher.NewCBCDecrypter(block, iv)
126 return cipher.NewCBCEncrypter(block, iv)
129 // macSHA1 returns a macFunction for the given protocol version.
130 func macSHA1(version uint16, key []byte) macFunction {
131 if version == VersionSSL30 {
134 key: make([]byte, len(key)),
141 h = newConstantTimeHash(h)
143 return tls10MAC{hmac.New(h, key)}
146 // macSHA256 returns a SHA-256 based MAC. These are only supported in TLS 1.2
147 // so the given version is ignored.
148 func macSHA256(version uint16, key []byte) macFunction {
149 return tls10MAC{hmac.New(sha256.New, key)}
152 type macFunction interface {
154 MAC(digestBuf, seq, header, data, extra []byte) []byte
157 type aead interface {
160 // explicitIVLen returns the number of bytes used by the explicit nonce
161 // that is included in the record. This is eight for older AEADs and
162 // zero for modern ones.
163 explicitNonceLen() int
166 // fixedNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
168 type fixedNonceAEAD struct {
169 // nonce contains the fixed part of the nonce in the first four bytes.
174 func (f *fixedNonceAEAD) NonceSize() int { return 8 }
175 func (f *fixedNonceAEAD) Overhead() int { return f.aead.Overhead() }
176 func (f *fixedNonceAEAD) explicitNonceLen() int { return 8 }
178 func (f *fixedNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
179 copy(f.nonce[4:], nonce)
180 return f.aead.Seal(out, f.nonce[:], plaintext, additionalData)
183 func (f *fixedNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
184 copy(f.nonce[4:], nonce)
185 return f.aead.Open(out, f.nonce[:], plaintext, additionalData)
188 // xoredNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
190 type xorNonceAEAD struct {
195 func (f *xorNonceAEAD) NonceSize() int { return 8 }
196 func (f *xorNonceAEAD) Overhead() int { return f.aead.Overhead() }
197 func (f *xorNonceAEAD) explicitNonceLen() int { return 0 }
199 func (f *xorNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
200 for i, b := range nonce {
201 f.nonceMask[4+i] ^= b
203 result := f.aead.Seal(out, f.nonceMask[:], plaintext, additionalData)
204 for i, b := range nonce {
205 f.nonceMask[4+i] ^= b
211 func (f *xorNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
212 for i, b := range nonce {
213 f.nonceMask[4+i] ^= b
215 result, err := f.aead.Open(out, f.nonceMask[:], plaintext, additionalData)
216 for i, b := range nonce {
217 f.nonceMask[4+i] ^= b
223 type gcmtls interface {
224 NewGCMTLS() (cipher.AEAD, error)
227 func aeadAESGCM(key, fixedNonce []byte) cipher.AEAD {
228 aes, err := aes.NewCipher(key)
233 if aesTLS, ok := aes.(gcmtls); ok {
234 aead, err = aesTLS.NewGCMTLS()
237 aead, err = cipher.NewGCM(aes)
243 ret := &fixedNonceAEAD{aead: aead}
244 copy(ret.nonce[:], fixedNonce)
248 func aeadChaCha20Poly1305(key, fixedNonce []byte) cipher.AEAD {
249 aead, err := chacha20poly1305.New(key)
254 ret := &xorNonceAEAD{aead: aead}
255 copy(ret.nonceMask[:], fixedNonce)
259 // ssl30MAC implements the SSLv3 MAC function, as defined in
260 // www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1
261 type ssl30MAC struct {
266 func (s ssl30MAC) Size() int {
270 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}
272 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}
274 // MAC does not offer constant timing guarantees for SSL v3.0, since it's deemed
275 // useless considering the similar, protocol-level POODLE vulnerability.
276 func (s ssl30MAC) MAC(digestBuf, seq, header, data, extra []byte) []byte {
278 if s.h.Size() == 20 {
284 s.h.Write(ssl30Pad1[:padLength])
286 s.h.Write(header[:1])
287 s.h.Write(header[3:5])
289 digestBuf = s.h.Sum(digestBuf[:0])
293 s.h.Write(ssl30Pad2[:padLength])
295 return s.h.Sum(digestBuf[:0])
298 type constantTimeHash interface {
300 ConstantTimeSum(b []byte) []byte
303 // cthWrapper wraps any hash.Hash that implements ConstantTimeSum, and replaces
304 // with that all calls to Sum. It's used to obtain a ConstantTimeSum-based HMAC.
305 type cthWrapper struct {
309 func (c *cthWrapper) Size() int { return c.h.Size() }
310 func (c *cthWrapper) BlockSize() int { return c.h.BlockSize() }
311 func (c *cthWrapper) Reset() { c.h.Reset() }
312 func (c *cthWrapper) Write(p []byte) (int, error) { return c.h.Write(p) }
313 func (c *cthWrapper) Sum(b []byte) []byte { return c.h.ConstantTimeSum(b) }
315 func newConstantTimeHash(h func() hash.Hash) func() hash.Hash {
317 // The BoringCrypto SHA1 does not have a constant-time
318 // checksum function, so don't try to use it.
321 return func() hash.Hash {
322 return &cthWrapper{h().(constantTimeHash)}
326 // tls10MAC implements the TLS 1.0 MAC function. RFC 2246, section 6.2.3.
327 type tls10MAC struct {
331 func (s tls10MAC) Size() int {
335 // MAC is guaranteed to take constant time, as long as
336 // len(seq)+len(header)+len(data)+len(extra) is constant. extra is not fed into
337 // the MAC, but is only provided to make the timing profile constant.
338 func (s tls10MAC) MAC(digestBuf, seq, header, data, extra []byte) []byte {
343 res := s.h.Sum(digestBuf[:0])
350 func rsaKA(version uint16) keyAgreement {
351 return rsaKeyAgreement{}
354 func ecdheECDSAKA(version uint16) keyAgreement {
355 return &ecdheKeyAgreement{
356 sigType: signatureECDSA,
361 func ecdheRSAKA(version uint16) keyAgreement {
362 return &ecdheKeyAgreement{
363 sigType: signatureRSA,
368 // mutualCipherSuite returns a cipherSuite given a list of supported
369 // ciphersuites and the id requested by the peer.
370 func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
371 for _, id := range have {
373 for _, suite := range cipherSuites {
374 if suite.id == want {
384 // A list of cipher suite IDs that are, or have been, implemented by this
387 // Taken from http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
389 TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
390 TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a
391 TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
392 TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035
393 TLS_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0x003c
394 TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c
395 TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d
396 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007
397 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009
398 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a
399 TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
400 TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012
401 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
402 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014
403 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
404 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc027
405 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f
406 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
407 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030
408 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
409 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 uint16 = 0xcca8
410 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 uint16 = 0xcca9
412 // TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
413 // that the client is doing version fallback. See
414 // https://tools.ietf.org/html/rfc7507.
415 TLS_FALLBACK_SCSV uint16 = 0x5600