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.
7 import "crypto/internal/boring"
23 "golang.org/x/crypto/chacha20poly1305"
26 // CipherSuite is a TLS cipher suite. Note that most functions in this package
27 // accept and expose cipher suite IDs instead of this type.
28 type CipherSuite struct {
32 // Supported versions is the list of TLS protocol versions that can
33 // negotiate this cipher suite.
34 SupportedVersions []uint16
36 // Insecure is true if the cipher suite has known security issues
37 // due to its primitives, design, or implementation.
42 supportedUpToTLS12 = []uint16{VersionTLS10, VersionTLS11, VersionTLS12}
43 supportedOnlyTLS12 = []uint16{VersionTLS12}
44 supportedOnlyTLS13 = []uint16{VersionTLS13}
47 // CipherSuites returns a list of cipher suites currently implemented by this
48 // package, excluding those with security issues, which are returned by
49 // InsecureCipherSuites.
51 // The list is sorted by ID. Note that the default cipher suites selected by
52 // this package might depend on logic that can't be captured by a static list,
53 // and might not match those returned by this function.
54 func CipherSuites() []*CipherSuite {
55 return []*CipherSuite{
56 {TLS_RSA_WITH_AES_128_CBC_SHA, "TLS_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
57 {TLS_RSA_WITH_AES_256_CBC_SHA, "TLS_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
58 {TLS_RSA_WITH_AES_128_GCM_SHA256, "TLS_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
59 {TLS_RSA_WITH_AES_256_GCM_SHA384, "TLS_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
61 {TLS_AES_128_GCM_SHA256, "TLS_AES_128_GCM_SHA256", supportedOnlyTLS13, false},
62 {TLS_AES_256_GCM_SHA384, "TLS_AES_256_GCM_SHA384", supportedOnlyTLS13, false},
63 {TLS_CHACHA20_POLY1305_SHA256, "TLS_CHACHA20_POLY1305_SHA256", supportedOnlyTLS13, false},
65 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
66 {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
67 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", supportedUpToTLS12, false},
68 {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", supportedUpToTLS12, false},
69 {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
70 {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
71 {TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", supportedOnlyTLS12, false},
72 {TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", supportedOnlyTLS12, false},
73 {TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
74 {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256", supportedOnlyTLS12, false},
78 // InsecureCipherSuites returns a list of cipher suites currently implemented by
79 // this package and which have security issues.
81 // Most applications should not use the cipher suites in this list, and should
82 // only use those returned by CipherSuites.
83 func InsecureCipherSuites() []*CipherSuite {
84 // This list includes RC4, CBC_SHA256, and 3DES cipher suites. See
85 // cipherSuitesPreferenceOrder for details.
86 return []*CipherSuite{
87 {TLS_RSA_WITH_RC4_128_SHA, "TLS_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
88 {TLS_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
89 {TLS_RSA_WITH_AES_128_CBC_SHA256, "TLS_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
90 {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
91 {TLS_ECDHE_RSA_WITH_RC4_128_SHA, "TLS_ECDHE_RSA_WITH_RC4_128_SHA", supportedUpToTLS12, true},
92 {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA", supportedUpToTLS12, true},
93 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
94 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", supportedOnlyTLS12, true},
98 // CipherSuiteName returns the standard name for the passed cipher suite ID
99 // (e.g. "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256"), or a fallback representation
100 // of the ID value if the cipher suite is not implemented by this package.
101 func CipherSuiteName(id uint16) string {
102 for _, c := range CipherSuites() {
107 for _, c := range InsecureCipherSuites() {
112 return fmt.Sprintf("0x%04X", id)
116 // suiteECDHE indicates that the cipher suite involves elliptic curve
117 // Diffie-Hellman. This means that it should only be selected when the
118 // client indicates that it supports ECC with a curve and point format
119 // that we're happy with.
120 suiteECDHE = 1 << iota
121 // suiteECSign indicates that the cipher suite involves an ECDSA or
122 // EdDSA signature and therefore may only be selected when the server's
123 // certificate is ECDSA or EdDSA. If this is not set then the cipher suite
126 // suiteTLS12 indicates that the cipher suite should only be advertised
127 // and accepted when using TLS 1.2.
129 // suiteSHA384 indicates that the cipher suite uses SHA384 as the
134 // A cipherSuite is a TLS 1.0–1.2 cipher suite, and defines the key exchange
135 // mechanism, as well as the cipher+MAC pair or the AEAD.
136 type cipherSuite struct {
138 // the lengths, in bytes, of the key material needed for each component.
142 ka func(version uint16) keyAgreement
143 // flags is a bitmask of the suite* values, above.
145 cipher func(key, iv []byte, isRead bool) interface{}
146 mac func(key []byte) hash.Hash
147 aead func(key, fixedNonce []byte) aead
150 var cipherSuites = []*cipherSuite{ // TODO: replace with a map, since the order doesn't matter.
151 {TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
152 {TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
153 {TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
154 {TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadAESGCM},
155 {TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
156 {TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
157 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12, cipherAES, macSHA256, nil},
158 {TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
159 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, cipherAES, macSHA256, nil},
160 {TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
161 {TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
162 {TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherAES, macSHA1, nil},
163 {TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM},
164 {TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
165 {TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12, cipherAES, macSHA256, nil},
166 {TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
167 {TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
168 {TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
169 {TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil},
170 {TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, 0, cipherRC4, macSHA1, nil},
171 {TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE, cipherRC4, macSHA1, nil},
172 {TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECSign, cipherRC4, macSHA1, nil},
175 // selectCipherSuite returns the first TLS 1.0–1.2 cipher suite from ids which
176 // is also in supportedIDs and passes the ok filter.
177 func selectCipherSuite(ids, supportedIDs []uint16, ok func(*cipherSuite) bool) *cipherSuite {
178 for _, id := range ids {
179 candidate := cipherSuiteByID(id)
180 if candidate == nil || !ok(candidate) {
184 for _, suppID := range supportedIDs {
193 // A cipherSuiteTLS13 defines only the pair of the AEAD algorithm and hash
194 // algorithm to be used with HKDF. See RFC 8446, Appendix B.4.
195 type cipherSuiteTLS13 struct {
198 aead func(key, fixedNonce []byte) aead
202 var cipherSuitesTLS13 = []*cipherSuiteTLS13{ // TODO: replace with a map.
203 {TLS_AES_128_GCM_SHA256, 16, aeadAESGCMTLS13, crypto.SHA256},
204 {TLS_CHACHA20_POLY1305_SHA256, 32, aeadChaCha20Poly1305, crypto.SHA256},
205 {TLS_AES_256_GCM_SHA384, 32, aeadAESGCMTLS13, crypto.SHA384},
208 // cipherSuitesPreferenceOrder is the order in which we'll select (on the
209 // server) or advertise (on the client) TLS 1.0–1.2 cipher suites.
211 // Cipher suites are filtered but not reordered based on the application and
212 // peer's preferences, meaning we'll never select a suite lower in this list if
213 // any higher one is available. This makes it more defensible to keep weaker
214 // cipher suites enabled, especially on the server side where we get the last
215 // word, since there are no known downgrade attacks on cipher suites selection.
217 // The list is sorted by applying the following priority rules, stopping at the
218 // first (most important) applicable one:
220 // - Anything else comes before RC4
222 // RC4 has practically exploitable biases. See https://www.rc4nomore.com.
224 // - Anything else comes before CBC_SHA256
226 // SHA-256 variants of the CBC ciphersuites don't implement any Lucky13
227 // countermeasures. See http://www.isg.rhul.ac.uk/tls/Lucky13.html and
228 // https://www.imperialviolet.org/2013/02/04/luckythirteen.html.
230 // - Anything else comes before 3DES
232 // 3DES has 64-bit blocks, which makes it fundamentally susceptible to
233 // birthday attacks. See https://sweet32.info.
235 // - ECDHE comes before anything else
237 // Once we got the broken stuff out of the way, the most important
238 // property a cipher suite can have is forward secrecy. We don't
239 // implement FFDHE, so that means ECDHE.
241 // - AEADs come before CBC ciphers
243 // Even with Lucky13 countermeasures, MAC-then-Encrypt CBC cipher suites
244 // are fundamentally fragile, and suffered from an endless sequence of
245 // padding oracle attacks. See https://eprint.iacr.org/2015/1129,
246 // https://www.imperialviolet.org/2014/12/08/poodleagain.html, and
247 // https://blog.cloudflare.com/yet-another-padding-oracle-in-openssl-cbc-ciphersuites/.
249 // - AES comes before ChaCha20
251 // When AES hardware is available, AES-128-GCM and AES-256-GCM are faster
252 // than ChaCha20Poly1305.
254 // When AES hardware is not available, AES-128-GCM is one or more of: much
255 // slower, way more complex, and less safe (because not constant time)
256 // than ChaCha20Poly1305.
258 // We use this list if we think both peers have AES hardware, and
259 // cipherSuitesPreferenceOrderNoAES otherwise.
261 // - AES-128 comes before AES-256
263 // The only potential advantages of AES-256 are better multi-target
264 // margins, and hypothetical post-quantum properties. Neither apply to
265 // TLS, and AES-256 is slower due to its four extra rounds (which don't
266 // contribute to the advantages above).
268 // - ECDSA comes before RSA
270 // The relative order of ECDSA and RSA cipher suites doesn't matter,
271 // as they depend on the certificate. Pick one to get a stable order.
273 var cipherSuitesPreferenceOrder = []uint16{
275 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
276 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
277 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
280 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
281 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
284 TLS_RSA_WITH_AES_128_GCM_SHA256,
285 TLS_RSA_WITH_AES_256_GCM_SHA384,
288 TLS_RSA_WITH_AES_128_CBC_SHA,
289 TLS_RSA_WITH_AES_256_CBC_SHA,
292 TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
293 TLS_RSA_WITH_3DES_EDE_CBC_SHA,
296 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
297 TLS_RSA_WITH_AES_128_CBC_SHA256,
300 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
301 TLS_RSA_WITH_RC4_128_SHA,
304 var cipherSuitesPreferenceOrderNoAES = []uint16{
306 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
309 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
310 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
312 // The rest of cipherSuitesPreferenceOrder.
313 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
314 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
315 TLS_RSA_WITH_AES_128_GCM_SHA256,
316 TLS_RSA_WITH_AES_256_GCM_SHA384,
317 TLS_RSA_WITH_AES_128_CBC_SHA,
318 TLS_RSA_WITH_AES_256_CBC_SHA,
319 TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
320 TLS_RSA_WITH_3DES_EDE_CBC_SHA,
321 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
322 TLS_RSA_WITH_AES_128_CBC_SHA256,
323 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
324 TLS_RSA_WITH_RC4_128_SHA,
327 // disabledCipherSuites are not used unless explicitly listed in
328 // Config.CipherSuites. They MUST be at the end of cipherSuitesPreferenceOrder.
329 var disabledCipherSuites = []uint16{
331 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
332 TLS_RSA_WITH_AES_128_CBC_SHA256,
335 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_RC4_128_SHA,
336 TLS_RSA_WITH_RC4_128_SHA,
340 defaultCipherSuitesLen = len(cipherSuitesPreferenceOrder) - len(disabledCipherSuites)
341 defaultCipherSuites = cipherSuitesPreferenceOrder[:defaultCipherSuitesLen]
344 // defaultCipherSuitesTLS13 is also the preference order, since there are no
345 // disabled by default TLS 1.3 cipher suites. The same AES vs ChaCha20 logic as
346 // cipherSuitesPreferenceOrder applies.
347 var defaultCipherSuitesTLS13 = []uint16{
348 TLS_AES_128_GCM_SHA256,
349 TLS_AES_256_GCM_SHA384,
350 TLS_CHACHA20_POLY1305_SHA256,
353 var defaultCipherSuitesTLS13NoAES = []uint16{
354 TLS_CHACHA20_POLY1305_SHA256,
355 TLS_AES_128_GCM_SHA256,
356 TLS_AES_256_GCM_SHA384,
360 hasGCMAsmAMD64 = cpu.X86.HasAES && cpu.X86.HasPCLMULQDQ
361 hasGCMAsmARM64 = cpu.ARM64.HasAES && cpu.ARM64.HasPMULL
362 // Keep in sync with crypto/aes/cipher_s390x.go.
363 hasGCMAsmS390X = cpu.S390X.HasAES && cpu.S390X.HasAESCBC && cpu.S390X.HasAESCTR &&
364 (cpu.S390X.HasGHASH || cpu.S390X.HasAESGCM)
366 hasAESGCMHardwareSupport = runtime.GOARCH == "amd64" && hasGCMAsmAMD64 ||
367 runtime.GOARCH == "arm64" && hasGCMAsmARM64 ||
368 runtime.GOARCH == "s390x" && hasGCMAsmS390X
371 var aesgcmCiphers = map[uint16]bool{
373 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256: true,
374 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384: true,
375 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256: true,
376 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384: true,
378 TLS_AES_128_GCM_SHA256: true,
379 TLS_AES_256_GCM_SHA384: true,
382 var nonAESGCMAEADCiphers = map[uint16]bool{
384 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305: true,
385 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305: true,
387 TLS_CHACHA20_POLY1305_SHA256: true,
390 // aesgcmPreferred returns whether the first known cipher in the preference list
391 // is an AES-GCM cipher, implying the peer has hardware support for it.
392 func aesgcmPreferred(ciphers []uint16) bool {
393 for _, cID := range ciphers {
394 if c := cipherSuiteByID(cID); c != nil {
395 return aesgcmCiphers[cID]
397 if c := cipherSuiteTLS13ByID(cID); c != nil {
398 return aesgcmCiphers[cID]
404 func cipherRC4(key, iv []byte, isRead bool) interface{} {
405 cipher, _ := rc4.NewCipher(key)
409 func cipher3DES(key, iv []byte, isRead bool) interface{} {
410 block, _ := des.NewTripleDESCipher(key)
412 return cipher.NewCBCDecrypter(block, iv)
414 return cipher.NewCBCEncrypter(block, iv)
417 func cipherAES(key, iv []byte, isRead bool) interface{} {
418 block, _ := aes.NewCipher(key)
420 return cipher.NewCBCDecrypter(block, iv)
422 return cipher.NewCBCEncrypter(block, iv)
425 // macSHA1 returns a SHA-1 based constant time MAC.
426 func macSHA1(key []byte) hash.Hash {
428 // The BoringCrypto SHA1 does not have a constant-time
429 // checksum function, so don't try to use it.
431 h = newConstantTimeHash(h)
433 return hmac.New(h, key)
436 // macSHA256 returns a SHA-256 based MAC. This is only supported in TLS 1.2 and
437 // is currently only used in disabled-by-default cipher suites.
438 func macSHA256(key []byte) hash.Hash {
439 return hmac.New(sha256.New, key)
442 type aead interface {
445 // explicitNonceLen returns the number of bytes of explicit nonce
446 // included in each record. This is eight for older AEADs and
447 // zero for modern ones.
448 explicitNonceLen() int
453 noncePrefixLength = 4
456 // prefixNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
458 type prefixNonceAEAD struct {
459 // nonce contains the fixed part of the nonce in the first four bytes.
460 nonce [aeadNonceLength]byte
464 func (f *prefixNonceAEAD) NonceSize() int { return aeadNonceLength - noncePrefixLength }
465 func (f *prefixNonceAEAD) Overhead() int { return f.aead.Overhead() }
466 func (f *prefixNonceAEAD) explicitNonceLen() int { return f.NonceSize() }
468 func (f *prefixNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
469 copy(f.nonce[4:], nonce)
470 return f.aead.Seal(out, f.nonce[:], plaintext, additionalData)
473 func (f *prefixNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
474 copy(f.nonce[4:], nonce)
475 return f.aead.Open(out, f.nonce[:], ciphertext, additionalData)
478 // xoredNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
480 type xorNonceAEAD struct {
481 nonceMask [aeadNonceLength]byte
485 func (f *xorNonceAEAD) NonceSize() int { return 8 } // 64-bit sequence number
486 func (f *xorNonceAEAD) Overhead() int { return f.aead.Overhead() }
487 func (f *xorNonceAEAD) explicitNonceLen() int { return 0 }
489 func (f *xorNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
490 for i, b := range nonce {
491 f.nonceMask[4+i] ^= b
493 result := f.aead.Seal(out, f.nonceMask[:], plaintext, additionalData)
494 for i, b := range nonce {
495 f.nonceMask[4+i] ^= b
501 func (f *xorNonceAEAD) Open(out, nonce, ciphertext, additionalData []byte) ([]byte, error) {
502 for i, b := range nonce {
503 f.nonceMask[4+i] ^= b
505 result, err := f.aead.Open(out, f.nonceMask[:], ciphertext, additionalData)
506 for i, b := range nonce {
507 f.nonceMask[4+i] ^= b
513 func aeadAESGCM(key, noncePrefix []byte) aead {
514 if len(noncePrefix) != noncePrefixLength {
515 panic("tls: internal error: wrong nonce length")
517 aes, err := aes.NewCipher(key)
521 type gcmtls interface {
522 NewGCMTLS() (cipher.AEAD, error)
525 if aesTLS, ok := aes.(gcmtls); ok {
526 aead, err = aesTLS.NewGCMTLS()
529 aead, err = cipher.NewGCM(aes)
535 ret := &prefixNonceAEAD{aead: aead}
536 copy(ret.nonce[:], noncePrefix)
540 func aeadAESGCMTLS13(key, nonceMask []byte) aead {
541 if len(nonceMask) != aeadNonceLength {
542 panic("tls: internal error: wrong nonce length")
544 aes, err := aes.NewCipher(key)
548 aead, err := cipher.NewGCM(aes)
553 ret := &xorNonceAEAD{aead: aead}
554 copy(ret.nonceMask[:], nonceMask)
558 func aeadChaCha20Poly1305(key, nonceMask []byte) aead {
559 if len(nonceMask) != aeadNonceLength {
560 panic("tls: internal error: wrong nonce length")
562 aead, err := chacha20poly1305.New(key)
567 ret := &xorNonceAEAD{aead: aead}
568 copy(ret.nonceMask[:], nonceMask)
572 type constantTimeHash interface {
574 ConstantTimeSum(b []byte) []byte
577 // cthWrapper wraps any hash.Hash that implements ConstantTimeSum, and replaces
578 // with that all calls to Sum. It's used to obtain a ConstantTimeSum-based HMAC.
579 type cthWrapper struct {
583 func (c *cthWrapper) Size() int { return c.h.Size() }
584 func (c *cthWrapper) BlockSize() int { return c.h.BlockSize() }
585 func (c *cthWrapper) Reset() { c.h.Reset() }
586 func (c *cthWrapper) Write(p []byte) (int, error) { return c.h.Write(p) }
587 func (c *cthWrapper) Sum(b []byte) []byte { return c.h.ConstantTimeSum(b) }
589 func newConstantTimeHash(h func() hash.Hash) func() hash.Hash {
591 return func() hash.Hash {
592 return &cthWrapper{h().(constantTimeHash)}
596 // tls10MAC implements the TLS 1.0 MAC function. RFC 2246, Section 6.2.3.
597 func tls10MAC(h hash.Hash, out, seq, header, data, extra []byte) []byte {
609 func rsaKA(version uint16) keyAgreement {
610 return rsaKeyAgreement{}
613 func ecdheECDSAKA(version uint16) keyAgreement {
614 return &ecdheKeyAgreement{
620 func ecdheRSAKA(version uint16) keyAgreement {
621 return &ecdheKeyAgreement{
627 // mutualCipherSuite returns a cipherSuite given a list of supported
628 // ciphersuites and the id requested by the peer.
629 func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
630 for _, id := range have {
632 return cipherSuiteByID(id)
638 func cipherSuiteByID(id uint16) *cipherSuite {
639 for _, cipherSuite := range cipherSuites {
640 if cipherSuite.id == id {
647 func mutualCipherSuiteTLS13(have []uint16, want uint16) *cipherSuiteTLS13 {
648 for _, id := range have {
650 return cipherSuiteTLS13ByID(id)
656 func cipherSuiteTLS13ByID(id uint16) *cipherSuiteTLS13 {
657 for _, cipherSuite := range cipherSuitesTLS13 {
658 if cipherSuite.id == id {
665 // A list of cipher suite IDs that are, or have been, implemented by this
668 // See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
670 // TLS 1.0 - 1.2 cipher suites.
671 TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
672 TLS_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0x000a
673 TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
674 TLS_RSA_WITH_AES_256_CBC_SHA uint16 = 0x0035
675 TLS_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0x003c
676 TLS_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0x009c
677 TLS_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0x009d
678 TLS_ECDHE_ECDSA_WITH_RC4_128_SHA uint16 = 0xc007
679 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA uint16 = 0xc009
680 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA uint16 = 0xc00a
681 TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
682 TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA uint16 = 0xc012
683 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
684 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA uint16 = 0xc014
685 TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
686 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc027
687 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02f
688 TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
689 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc030
690 TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
691 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca8
692 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 uint16 = 0xcca9
694 // TLS 1.3 cipher suites.
695 TLS_AES_128_GCM_SHA256 uint16 = 0x1301
696 TLS_AES_256_GCM_SHA384 uint16 = 0x1302
697 TLS_CHACHA20_POLY1305_SHA256 uint16 = 0x1303
699 // TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
700 // that the client is doing version fallback. See RFC 7507.
701 TLS_FALLBACK_SCSV uint16 = 0x5600
703 // Legacy names for the corresponding cipher suites with the correct _SHA256
704 // suffix, retained for backward compatibility.
705 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
706 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305 = TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256