github.com/goproxy0/go@v0.0.0-20171111080102-49cc0c489d2c/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/sha256"
    15  	"crypto/x509"
    16  	"hash"
    17  
    18  	"golang_org/x/crypto/chacha20poly1305"
    19  )
    20  
    21  // a keyAgreement implements the client and server side of a TLS key agreement
    22  // protocol by generating and processing key exchange messages.
    23  type keyAgreement interface {
    24  	// On the server side, the first two methods are called in order.
    25  
    26  	// In the case that the key agreement protocol doesn't use a
    27  	// ServerKeyExchange message, generateServerKeyExchange can return nil,
    28  	// nil.
    29  	generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
    30  	processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
    31  
    32  	// On the client side, the next two methods are called in order.
    33  
    34  	// This method may not be called if the server doesn't send a
    35  	// ServerKeyExchange message.
    36  	processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error
    37  	generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
    38  }
    39  
    40  const (
    41  	// suiteECDH indicates that the cipher suite involves elliptic curve
    42  	// Diffie-Hellman. This means that it should only be selected when the
    43  	// client indicates that it supports ECC with a curve and point format
    44  	// that we're happy with.
    45  	suiteECDHE = 1 << iota
    46  	// suiteECDSA indicates that the cipher suite involves an ECDSA
    47  	// signature and therefore may only be selected when the server's
    48  	// certificate is ECDSA. If this is not set then the cipher suite is
    49  	// RSA based.
    50  	suiteECDSA
    51  	// suiteTLS12 indicates that the cipher suite should only be advertised
    52  	// and accepted when using TLS 1.2.
    53  	suiteTLS12
    54  	// suiteTLS13 indicates that the ones and only cipher suites to be
    55  	// advertised and accepted when using TLS 1.3.
    56  	suiteTLS13
    57  	// suiteSHA384 indicates that the cipher suite uses SHA384 as the
    58  	// handshake hash.
    59  	suiteSHA384
    60  	// suiteDefaultOff indicates that this cipher suite is not included by
    61  	// default.
    62  	suiteDefaultOff
    63  )
    64  
    65  // A cipherSuite is a specific combination of key agreement, cipher and MAC
    66  // function.
    67  type cipherSuite struct {
    68  	id uint16
    69  	// the lengths, in bytes, of the key material needed for each component.
    70  	keyLen int
    71  	macLen int
    72  	ivLen  int
    73  	ka     func(version uint16) keyAgreement
    74  	// flags is a bitmask of the suite* values, above.
    75  	flags  int
    76  	cipher func(key, iv []byte, isRead bool) interface{}
    77  	mac    func(version uint16, macKey []byte) macFunction
    78  	aead   func(key, fixedNonce []byte) cipher.AEAD
    79  }
    80  
    81  var cipherSuites = []*cipherSuite{
    82  	// TLS 1.3 ciphersuites specify only the AEAD and the HKDF hash.
    83  	{TLS_CHACHA20_POLY1305_SHA256, 32, 0, 12, nil, suiteTLS13, nil, nil, aeadChaCha20Poly1305},
    84  	{TLS_AES_128_GCM_SHA256, 16, 0, 4, nil, suiteTLS13, nil, nil, aeadAESGCM13},
    85  	{TLS_AES_256_GCM_SHA384, 32, 0, 4, nil, suiteTLS13 | suiteSHA384, nil, nil, aeadAESGCM13},
    86  
    87  	// Ciphersuite order is chosen so that ECDHE comes before plain RSA and
    88  	// AEADs are the top preference.
    89  	{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
    90  	{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
    91  	{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM12},
    92  	{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12, nil, nil, aeadAESGCM12},
    93  	{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM12},
    94  	{TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM12},
    95  	{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
    96  	{TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
    97  	{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
    98  	{TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, 16, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
    99  	{TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheRSAKA, suiteECDHE, cipherAES, macSHA1, nil},
   100  	{TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, 32, 20, 16, ecdheECDSAKA, suiteECDHE | suiteECDSA, cipherAES, macSHA1, nil},
   101  	{TLS_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, rsaKA, suiteTLS12, nil, nil, aeadAESGCM12},
   102  	{TLS_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, rsaKA, suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM12},
   103  	{TLS_RSA_WITH_AES_128_CBC_SHA256, 16, 32, 16, rsaKA, suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
   104  	{TLS_RSA_WITH_AES_256_CBC_SHA256, 32, 32, 16, rsaKA, suiteTLS12 | suiteDefaultOff, cipherAES, macSHA256, nil},
   105  	{TLS_RSA_WITH_AES_128_CBC_SHA, 16, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
   106  	{TLS_RSA_WITH_AES_256_CBC_SHA, 32, 20, 16, rsaKA, 0, cipherAES, macSHA1, nil},
   107  	{TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, ecdheRSAKA, suiteECDHE, cipher3DES, macSHA1, nil},
   108  	{TLS_RSA_WITH_3DES_EDE_CBC_SHA, 24, 20, 8, rsaKA, 0, cipher3DES, macSHA1, nil},
   109  
   110  	// RC4-based cipher suites are disabled by default.
   111  	{TLS_RSA_WITH_RC4_128_SHA, 16, 20, 0, rsaKA, suiteDefaultOff, cipherRC4, macSHA1, nil},
   112  	{TLS_ECDHE_RSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheRSAKA, suiteECDHE | suiteDefaultOff, cipherRC4, macSHA1, nil},
   113  	{TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, 16, 20, 0, ecdheECDSAKA, suiteECDHE | suiteECDSA | suiteDefaultOff, cipherRC4, macSHA1, nil},
   114  }
   115  
   116  func cipherRC4(key, iv []byte, isRead bool) interface{} {
   117  	cipher, _ := rc4.NewCipher(key)
   118  	return cipher
   119  }
   120  
   121  func cipher3DES(key, iv []byte, isRead bool) interface{} {
   122  	block, _ := des.NewTripleDESCipher(key)
   123  	if isRead {
   124  		return cipher.NewCBCDecrypter(block, iv)
   125  	}
   126  	return cipher.NewCBCEncrypter(block, iv)
   127  }
   128  
   129  func cipherAES(key, iv []byte, isRead bool) interface{} {
   130  	block, _ := aes.NewCipher(key)
   131  	if isRead {
   132  		return cipher.NewCBCDecrypter(block, iv)
   133  	}
   134  	return cipher.NewCBCEncrypter(block, iv)
   135  }
   136  
   137  // macSHA1 returns a macFunction for the given protocol version.
   138  func macSHA1(version uint16, key []byte) macFunction {
   139  	if version == VersionSSL30 {
   140  		mac := ssl30MAC{
   141  			h:   sha1.New(),
   142  			key: make([]byte, len(key)),
   143  		}
   144  		copy(mac.key, key)
   145  		return mac
   146  	}
   147  	return tls10MAC{hmac.New(newConstantTimeHash(sha1.New), key)}
   148  }
   149  
   150  // macSHA256 returns a SHA-256 based MAC. These are only supported in TLS 1.2
   151  // so the given version is ignored.
   152  func macSHA256(version uint16, key []byte) macFunction {
   153  	return tls10MAC{hmac.New(sha256.New, key)}
   154  }
   155  
   156  type macFunction interface {
   157  	Size() int
   158  	MAC(digestBuf, seq, header, data, extra []byte) []byte
   159  }
   160  
   161  type aead interface {
   162  	cipher.AEAD
   163  
   164  	// explicitIVLen returns the number of bytes used by the explicit nonce
   165  	// that is included in the record. This is eight for older AEADs and
   166  	// zero for modern ones.
   167  	explicitNonceLen() int
   168  }
   169  
   170  // fixedNonceAEAD wraps an AEAD and prefixes a fixed portion of the nonce to
   171  // each call.
   172  type fixedNonceAEAD struct {
   173  	// nonce contains the fixed part of the nonce in the first four bytes.
   174  	nonce [12]byte
   175  	aead  cipher.AEAD
   176  }
   177  
   178  func (f *fixedNonceAEAD) NonceSize() int        { return 8 }
   179  func (f *fixedNonceAEAD) Overhead() int         { return f.aead.Overhead() }
   180  func (f *fixedNonceAEAD) explicitNonceLen() int { return 8 }
   181  
   182  func (f *fixedNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
   183  	copy(f.nonce[4:], nonce)
   184  	return f.aead.Seal(out, f.nonce[:], plaintext, additionalData)
   185  }
   186  
   187  func (f *fixedNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
   188  	copy(f.nonce[4:], nonce)
   189  	return f.aead.Open(out, f.nonce[:], plaintext, additionalData)
   190  }
   191  
   192  // xoredNonceAEAD wraps an AEAD by XORing in a fixed pattern to the nonce
   193  // before each call.
   194  type xorNonceAEAD struct {
   195  	nonceMask [12]byte
   196  	aead      cipher.AEAD
   197  }
   198  
   199  func (f *xorNonceAEAD) NonceSize() int        { return 8 }
   200  func (f *xorNonceAEAD) Overhead() int         { return f.aead.Overhead() }
   201  func (f *xorNonceAEAD) explicitNonceLen() int { return 0 }
   202  
   203  func (f *xorNonceAEAD) Seal(out, nonce, plaintext, additionalData []byte) []byte {
   204  	for i, b := range nonce {
   205  		f.nonceMask[4+i] ^= b
   206  	}
   207  	result := f.aead.Seal(out, f.nonceMask[:], plaintext, additionalData)
   208  	for i, b := range nonce {
   209  		f.nonceMask[4+i] ^= b
   210  	}
   211  
   212  	return result
   213  }
   214  
   215  func (f *xorNonceAEAD) Open(out, nonce, plaintext, additionalData []byte) ([]byte, error) {
   216  	for i, b := range nonce {
   217  		f.nonceMask[4+i] ^= b
   218  	}
   219  	result, err := f.aead.Open(out, f.nonceMask[:], plaintext, additionalData)
   220  	for i, b := range nonce {
   221  		f.nonceMask[4+i] ^= b
   222  	}
   223  
   224  	return result, err
   225  }
   226  
   227  func aeadAESGCM12(key, fixedNonce []byte) cipher.AEAD {
   228  	aes, err := aes.NewCipher(key)
   229  	if err != nil {
   230  		panic(err)
   231  	}
   232  	aead, err := cipher.NewGCM(aes)
   233  	if err != nil {
   234  		panic(err)
   235  	}
   236  
   237  	ret := &fixedNonceAEAD{aead: aead}
   238  	copy(ret.nonce[:], fixedNonce)
   239  	return ret
   240  }
   241  
   242  func aeadAESGCM13(key, fixedNonce []byte) cipher.AEAD {
   243  	aes, err := aes.NewCipher(key)
   244  	if err != nil {
   245  		panic(err)
   246  	}
   247  	aead, err := cipher.NewGCM(aes)
   248  	if err != nil {
   249  		panic(err)
   250  	}
   251  
   252  	ret := &xorNonceAEAD{aead: aead}
   253  	copy(ret.nonceMask[:], fixedNonce)
   254  	return ret
   255  }
   256  
   257  func aeadChaCha20Poly1305(key, fixedNonce []byte) cipher.AEAD {
   258  	aead, err := chacha20poly1305.New(key)
   259  	if err != nil {
   260  		panic(err)
   261  	}
   262  
   263  	ret := &xorNonceAEAD{aead: aead}
   264  	copy(ret.nonceMask[:], fixedNonce)
   265  	return ret
   266  }
   267  
   268  // ssl30MAC implements the SSLv3 MAC function, as defined in
   269  // www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt section 5.2.3.1
   270  type ssl30MAC struct {
   271  	h   hash.Hash
   272  	key []byte
   273  }
   274  
   275  func (s ssl30MAC) Size() int {
   276  	return s.h.Size()
   277  }
   278  
   279  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}
   280  
   281  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}
   282  
   283  // MAC does not offer constant timing guarantees for SSL v3.0, since it's deemed
   284  // useless considering the similar, protocol-level POODLE vulnerability.
   285  func (s ssl30MAC) MAC(digestBuf, seq, header, data, extra []byte) []byte {
   286  	padLength := 48
   287  	if s.h.Size() == 20 {
   288  		padLength = 40
   289  	}
   290  
   291  	s.h.Reset()
   292  	s.h.Write(s.key)
   293  	s.h.Write(ssl30Pad1[:padLength])
   294  	s.h.Write(seq)
   295  	s.h.Write(header[:1])
   296  	s.h.Write(header[3:5])
   297  	s.h.Write(data)
   298  	digestBuf = s.h.Sum(digestBuf[:0])
   299  
   300  	s.h.Reset()
   301  	s.h.Write(s.key)
   302  	s.h.Write(ssl30Pad2[:padLength])
   303  	s.h.Write(digestBuf)
   304  	return s.h.Sum(digestBuf[:0])
   305  }
   306  
   307  type constantTimeHash interface {
   308  	hash.Hash
   309  	ConstantTimeSum(b []byte) []byte
   310  }
   311  
   312  // cthWrapper wraps any hash.Hash that implements ConstantTimeSum, and replaces
   313  // with that all calls to Sum. It's used to obtain a ConstantTimeSum-based HMAC.
   314  type cthWrapper struct {
   315  	h constantTimeHash
   316  }
   317  
   318  func (c *cthWrapper) Size() int                   { return c.h.Size() }
   319  func (c *cthWrapper) BlockSize() int              { return c.h.BlockSize() }
   320  func (c *cthWrapper) Reset()                      { c.h.Reset() }
   321  func (c *cthWrapper) Write(p []byte) (int, error) { return c.h.Write(p) }
   322  func (c *cthWrapper) Sum(b []byte) []byte         { return c.h.ConstantTimeSum(b) }
   323  
   324  func newConstantTimeHash(h func() hash.Hash) func() hash.Hash {
   325  	return func() hash.Hash {
   326  		return &cthWrapper{h().(constantTimeHash)}
   327  	}
   328  }
   329  
   330  // tls10MAC implements the TLS 1.0 MAC function. RFC 2246, section 6.2.3.
   331  type tls10MAC struct {
   332  	h hash.Hash
   333  }
   334  
   335  func (s tls10MAC) Size() int {
   336  	return s.h.Size()
   337  }
   338  
   339  // MAC is guaranteed to take constant time, as long as
   340  // len(seq)+len(header)+len(data)+len(extra) is constant. extra is not fed into
   341  // the MAC, but is only provided to make the timing profile constant.
   342  func (s tls10MAC) MAC(digestBuf, seq, header, data, extra []byte) []byte {
   343  	s.h.Reset()
   344  	s.h.Write(seq)
   345  	s.h.Write(header)
   346  	s.h.Write(data)
   347  	res := s.h.Sum(digestBuf[:0])
   348  	if extra != nil {
   349  		s.h.Write(extra)
   350  	}
   351  	return res
   352  }
   353  
   354  func rsaKA(version uint16) keyAgreement {
   355  	return rsaKeyAgreement{}
   356  }
   357  
   358  func ecdheECDSAKA(version uint16) keyAgreement {
   359  	return &ecdheKeyAgreement{
   360  		sigType: signatureECDSA,
   361  		version: version,
   362  	}
   363  }
   364  
   365  func ecdheRSAKA(version uint16) keyAgreement {
   366  	return &ecdheKeyAgreement{
   367  		sigType: signatureRSA,
   368  		version: version,
   369  	}
   370  }
   371  
   372  // mutualCipherSuite returns a cipherSuite given a list of supported
   373  // ciphersuites and the id requested by the peer.
   374  func mutualCipherSuite(have []uint16, want uint16) *cipherSuite {
   375  	for _, id := range have {
   376  		if id == want {
   377  			for _, suite := range cipherSuites {
   378  				if suite.id == want {
   379  					return suite
   380  				}
   381  			}
   382  			return nil
   383  		}
   384  	}
   385  	return nil
   386  }
   387  
   388  // A list of cipher suite IDs that are, or have been, implemented by this
   389  // package.
   390  //
   391  // Taken from http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
   392  const (
   393  	// TLS 1.0 - 1.2 cipher suites.
   394  	TLS_RSA_WITH_RC4_128_SHA                uint16 = 0x0005
   395  	TLS_RSA_WITH_3DES_EDE_CBC_SHA           uint16 = 0x000a
   396  	TLS_RSA_WITH_AES_128_CBC_SHA            uint16 = 0x002f
   397  	TLS_RSA_WITH_AES_256_CBC_SHA            uint16 = 0x0035
   398  	TLS_RSA_WITH_AES_128_CBC_SHA256         uint16 = 0x003c
   399  	TLS_RSA_WITH_AES_256_CBC_SHA256         uint16 = 0x003d
   400  	TLS_RSA_WITH_AES_128_GCM_SHA256         uint16 = 0x009c
   401  	TLS_RSA_WITH_AES_256_GCM_SHA384         uint16 = 0x009d
   402  	TLS_ECDHE_ECDSA_WITH_RC4_128_SHA        uint16 = 0xc007
   403  	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA    uint16 = 0xc009
   404  	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA    uint16 = 0xc00a
   405  	TLS_ECDHE_RSA_WITH_RC4_128_SHA          uint16 = 0xc011
   406  	TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA     uint16 = 0xc012
   407  	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA      uint16 = 0xc013
   408  	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA      uint16 = 0xc014
   409  	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 uint16 = 0xc023
   410  	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256   uint16 = 0xc027
   411  	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256   uint16 = 0xc02f
   412  	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 uint16 = 0xc02b
   413  	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384   uint16 = 0xc030
   414  	TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 uint16 = 0xc02c
   415  	TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305    uint16 = 0xcca8
   416  	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305  uint16 = 0xcca9
   417  
   418  	// TLS 1.3+ cipher suites.
   419  	TLS_AES_128_GCM_SHA256       uint16 = 0x1301
   420  	TLS_AES_256_GCM_SHA384       uint16 = 0x1302
   421  	TLS_CHACHA20_POLY1305_SHA256 uint16 = 0x1303
   422  
   423  	// TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator
   424  	// that the client is doing version fallback. See
   425  	// https://tools.ietf.org/html/rfc7507.
   426  	TLS_FALLBACK_SCSV uint16 = 0x5600
   427  )