From 6c380f3bb64954e9c15758272a1cc9c12a7e9678 Mon Sep 17 00:00:00 2001 From: Peter Wu Date: Thu, 7 Sep 2017 17:50:10 +0100 Subject: [PATCH] crypto/tls: replace signatureAndHash by SignatureScheme. Consolidate the signature and hash fields (SignatureAndHashAlgorithm in TLS 1.2) into a single uint16 (SignatureScheme in TLS 1.3 draft 21). This makes it easier to add RSASSA-PSS for TLS 1.2 in the future. Fields were named like "signatureAlgorithm" rather than "signatureScheme" since that name is also used throughout the 1.3 draft. The only new public symbol is ECDSAWithSHA1, other than that this is an internal change with no new functionality. Change-Id: Iba63d262ab1af895420583ac9e302d9705a7e0f0 Reviewed-on: https://go-review.googlesource.com/62210 Reviewed-by: Adam Langley --- common.go | 52 +++++++++++++++------------- handshake_client.go | 20 +++++------ handshake_messages.go | 71 ++++++++++++++++++-------------------- handshake_messages_test.go | 2 +- handshake_server.go | 32 ++++++++--------- key_agreement.go | 50 ++++++++++++++++----------- prf.go | 36 +++++++++---------- 7 files changed, 132 insertions(+), 131 deletions(-) diff --git a/common.go b/common.go index 1377648..8727802 100644 --- a/common.go +++ b/common.go @@ -126,35 +126,23 @@ const ( // Rest of these are reserved by the TLS spec ) -// Hash functions for TLS 1.2 (See RFC 5246, section A.4.1) -const ( - hashSHA1 uint8 = 2 - hashSHA256 uint8 = 4 - hashSHA384 uint8 = 5 -) - // Signature algorithms for TLS 1.2 (See RFC 5246, section A.4.1) const ( signatureRSA uint8 = 1 signatureECDSA uint8 = 3 ) -// signatureAndHash mirrors the TLS 1.2, SignatureAndHashAlgorithm struct. See -// RFC 5246, section A.4.1. -type signatureAndHash struct { - hash, signature uint8 -} - // supportedSignatureAlgorithms contains the signature and hash algorithms that // the code advertises as supported in a TLS 1.2 ClientHello and in a TLS 1.2 -// CertificateRequest. -var supportedSignatureAlgorithms = []signatureAndHash{ - {hashSHA256, signatureRSA}, - {hashSHA256, signatureECDSA}, - {hashSHA384, signatureRSA}, - {hashSHA384, signatureECDSA}, - {hashSHA1, signatureRSA}, - {hashSHA1, signatureECDSA}, +// CertificateRequest. The two fields are merged to match with TLS 1.3. +// Note that in TLS 1.2, the ECDSA algorithms are not constrained to P-256, etc. +var supportedSignatureAlgorithms = []SignatureScheme{ + PKCS1WithSHA256, + ECDSAWithP256AndSHA256, + PKCS1WithSHA384, + ECDSAWithP384AndSHA384, + PKCS1WithSHA1, + ECDSAWithSHA1, } // ConnectionState records basic TLS details about the connection. @@ -234,6 +222,9 @@ const ( ECDSAWithP256AndSHA256 SignatureScheme = 0x0403 ECDSAWithP384AndSHA384 SignatureScheme = 0x0503 ECDSAWithP521AndSHA512 SignatureScheme = 0x0603 + + // Legacy signature and hash algorithms for TLS 1.2. + ECDSAWithSHA1 SignatureScheme = 0x0203 ) // ClientHelloInfo contains information from a ClientHello message in order to @@ -961,11 +952,24 @@ func unexpectedMessageError(wanted, got interface{}) error { return fmt.Errorf("tls: received unexpected handshake message of type %T when waiting for %T", got, wanted) } -func isSupportedSignatureAndHash(sigHash signatureAndHash, sigHashes []signatureAndHash) bool { - for _, s := range sigHashes { - if s == sigHash { +func isSupportedSignatureAlgorithm(sigAlg SignatureScheme, supportedSignatureAlgorithms []SignatureScheme) bool { + for _, s := range supportedSignatureAlgorithms { + if s == sigAlg { return true } } return false } + +// signatureFromSignatureScheme maps a signature algorithm to the underlying +// signature method (without hash function). +func signatureFromSignatureScheme(signatureAlgorithm SignatureScheme) uint8 { + switch signatureAlgorithm { + case PKCS1WithSHA1, PKCS1WithSHA256, PKCS1WithSHA384, PKCS1WithSHA512: + return signatureRSA + case ECDSAWithSHA1, ECDSAWithP256AndSHA256, ECDSAWithP384AndSHA384, ECDSAWithP521AndSHA512: + return signatureECDSA + default: + return 0 + } +} diff --git a/handshake_client.go b/handshake_client.go index f8db662..dc529c9 100644 --- a/handshake_client.go +++ b/handshake_client.go @@ -85,7 +85,7 @@ NextCipherSuite: } if hello.vers >= VersionTLS12 { - hello.signatureAndHashes = supportedSignatureAlgorithms + hello.supportedSignatureAlgorithms = supportedSignatureAlgorithms } return hello, nil @@ -482,12 +482,15 @@ func (hs *clientHandshakeState) doFullHandshake() error { return fmt.Errorf("tls: failed to sign handshake with client certificate: unknown client certificate key type: %T", key) } - certVerify.signatureAndHash, err = hs.finishedHash.selectClientCertSignatureAlgorithm(certReq.signatureAndHashes, signatureType) - if err != nil { - c.sendAlert(alertInternalError) - return err + // SignatureAndHashAlgorithm was introduced in TLS 1.2. + if certVerify.hasSignatureAndHash { + certVerify.signatureAlgorithm, err = hs.finishedHash.selectClientCertSignatureAlgorithm(certReq.supportedSignatureAlgorithms, signatureType) + if err != nil { + c.sendAlert(alertInternalError) + return err + } } - digest, hashFunc, err := hs.finishedHash.hashForClientCertificate(certVerify.signatureAndHash, hs.masterSecret) + digest, hashFunc, err := hs.finishedHash.hashForClientCertificate(signatureType, certVerify.signatureAlgorithm, hs.masterSecret) if err != nil { c.sendAlert(alertInternalError) return err @@ -746,10 +749,7 @@ func (hs *clientHandshakeState) getCertificate(certReq *certificateRequestMsg) ( signatureSchemes = signatureSchemes[:len(signatureSchemes)-tls11SignatureSchemesNumRSA] } } else { - signatureSchemes = make([]SignatureScheme, 0, len(certReq.signatureAndHashes)) - for _, sah := range certReq.signatureAndHashes { - signatureSchemes = append(signatureSchemes, SignatureScheme(sah.hash)<<8+SignatureScheme(sah.signature)) - } + signatureSchemes = certReq.supportedSignatureAlgorithms } return c.config.GetClientCertificate(&CertificateRequestInfo{ diff --git a/handshake_messages.go b/handshake_messages.go index 0c7581f..f8c8d57 100644 --- a/handshake_messages.go +++ b/handshake_messages.go @@ -24,7 +24,7 @@ type clientHelloMsg struct { supportedPoints []uint8 ticketSupported bool sessionTicket []uint8 - signatureAndHashes []signatureAndHash + supportedSignatureAlgorithms []SignatureScheme secureRenegotiation []byte secureRenegotiationSupported bool alpnProtocols []string @@ -50,7 +50,7 @@ func (m *clientHelloMsg) equal(i interface{}) bool { bytes.Equal(m.supportedPoints, m1.supportedPoints) && m.ticketSupported == m1.ticketSupported && bytes.Equal(m.sessionTicket, m1.sessionTicket) && - eqSignatureAndHashes(m.signatureAndHashes, m1.signatureAndHashes) && + eqSignatureAlgorithms(m.supportedSignatureAlgorithms, m1.supportedSignatureAlgorithms) && m.secureRenegotiationSupported == m1.secureRenegotiationSupported && bytes.Equal(m.secureRenegotiation, m1.secureRenegotiation) && eqStrings(m.alpnProtocols, m1.alpnProtocols) @@ -87,8 +87,8 @@ func (m *clientHelloMsg) marshal() []byte { extensionsLength += len(m.sessionTicket) numExtensions++ } - if len(m.signatureAndHashes) > 0 { - extensionsLength += 2 + 2*len(m.signatureAndHashes) + if len(m.supportedSignatureAlgorithms) > 0 { + extensionsLength += 2 + 2*len(m.supportedSignatureAlgorithms) numExtensions++ } if m.secureRenegotiationSupported { @@ -234,11 +234,11 @@ func (m *clientHelloMsg) marshal() []byte { copy(z, m.sessionTicket) z = z[len(m.sessionTicket):] } - if len(m.signatureAndHashes) > 0 { + if len(m.supportedSignatureAlgorithms) > 0 { // https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 z[0] = byte(extensionSignatureAlgorithms >> 8) z[1] = byte(extensionSignatureAlgorithms) - l := 2 + 2*len(m.signatureAndHashes) + l := 2 + 2*len(m.supportedSignatureAlgorithms) z[2] = byte(l >> 8) z[3] = byte(l) z = z[4:] @@ -247,9 +247,9 @@ func (m *clientHelloMsg) marshal() []byte { z[0] = byte(l >> 8) z[1] = byte(l) z = z[2:] - for _, sigAndHash := range m.signatureAndHashes { - z[0] = sigAndHash.hash - z[1] = sigAndHash.signature + for _, sigAlgo := range m.supportedSignatureAlgorithms { + z[0] = byte(sigAlgo >> 8) + z[1] = byte(sigAlgo) z = z[2:] } } @@ -344,7 +344,7 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool { m.ocspStapling = false m.ticketSupported = false m.sessionTicket = nil - m.signatureAndHashes = nil + m.supportedSignatureAlgorithms = nil m.alpnProtocols = nil m.scts = false @@ -455,10 +455,9 @@ func (m *clientHelloMsg) unmarshal(data []byte) bool { } n := l / 2 d := data[2:] - m.signatureAndHashes = make([]signatureAndHash, n) - for i := range m.signatureAndHashes { - m.signatureAndHashes[i].hash = d[0] - m.signatureAndHashes[i].signature = d[1] + m.supportedSignatureAlgorithms = make([]SignatureScheme, n) + for i := range m.supportedSignatureAlgorithms { + m.supportedSignatureAlgorithms[i] = SignatureScheme(d[0])<<8 | SignatureScheme(d[1]) d = d[2:] } case extensionRenegotiationInfo: @@ -1203,9 +1202,9 @@ type certificateRequestMsg struct { // 1.2. hasSignatureAndHash bool - certificateTypes []byte - signatureAndHashes []signatureAndHash - certificateAuthorities [][]byte + certificateTypes []byte + supportedSignatureAlgorithms []SignatureScheme + certificateAuthorities [][]byte } func (m *certificateRequestMsg) equal(i interface{}) bool { @@ -1217,7 +1216,7 @@ func (m *certificateRequestMsg) equal(i interface{}) bool { return bytes.Equal(m.raw, m1.raw) && bytes.Equal(m.certificateTypes, m1.certificateTypes) && eqByteSlices(m.certificateAuthorities, m1.certificateAuthorities) && - eqSignatureAndHashes(m.signatureAndHashes, m1.signatureAndHashes) + eqSignatureAlgorithms(m.supportedSignatureAlgorithms, m1.supportedSignatureAlgorithms) } func (m *certificateRequestMsg) marshal() (x []byte) { @@ -1234,7 +1233,7 @@ func (m *certificateRequestMsg) marshal() (x []byte) { length += casLength if m.hasSignatureAndHash { - length += 2 + 2*len(m.signatureAndHashes) + length += 2 + 2*len(m.supportedSignatureAlgorithms) } x = make([]byte, 4+length) @@ -1249,13 +1248,13 @@ func (m *certificateRequestMsg) marshal() (x []byte) { y := x[5+len(m.certificateTypes):] if m.hasSignatureAndHash { - n := len(m.signatureAndHashes) * 2 + n := len(m.supportedSignatureAlgorithms) * 2 y[0] = uint8(n >> 8) y[1] = uint8(n) y = y[2:] - for _, sigAndHash := range m.signatureAndHashes { - y[0] = sigAndHash.hash - y[1] = sigAndHash.signature + for _, sigAlgo := range m.supportedSignatureAlgorithms { + y[0] = uint8(sigAlgo >> 8) + y[1] = uint8(sigAlgo) y = y[2:] } } @@ -1312,11 +1311,10 @@ func (m *certificateRequestMsg) unmarshal(data []byte) bool { if len(data) < int(sigAndHashLen) { return false } - numSigAndHash := sigAndHashLen / 2 - m.signatureAndHashes = make([]signatureAndHash, numSigAndHash) - for i := range m.signatureAndHashes { - m.signatureAndHashes[i].hash = data[0] - m.signatureAndHashes[i].signature = data[1] + numSigAlgos := sigAndHashLen / 2 + m.supportedSignatureAlgorithms = make([]SignatureScheme, numSigAlgos) + for i := range m.supportedSignatureAlgorithms { + m.supportedSignatureAlgorithms[i] = SignatureScheme(data[0])<<8 | SignatureScheme(data[1]) data = data[2:] } } @@ -1355,7 +1353,7 @@ func (m *certificateRequestMsg) unmarshal(data []byte) bool { type certificateVerifyMsg struct { raw []byte hasSignatureAndHash bool - signatureAndHash signatureAndHash + signatureAlgorithm SignatureScheme signature []byte } @@ -1367,8 +1365,7 @@ func (m *certificateVerifyMsg) equal(i interface{}) bool { return bytes.Equal(m.raw, m1.raw) && m.hasSignatureAndHash == m1.hasSignatureAndHash && - m.signatureAndHash.hash == m1.signatureAndHash.hash && - m.signatureAndHash.signature == m1.signatureAndHash.signature && + m.signatureAlgorithm == m1.signatureAlgorithm && bytes.Equal(m.signature, m1.signature) } @@ -1390,8 +1387,8 @@ func (m *certificateVerifyMsg) marshal() (x []byte) { x[3] = uint8(length) y := x[4:] if m.hasSignatureAndHash { - y[0] = m.signatureAndHash.hash - y[1] = m.signatureAndHash.signature + y[0] = uint8(m.signatureAlgorithm >> 8) + y[1] = uint8(m.signatureAlgorithm) y = y[2:] } y[0] = uint8(siglength >> 8) @@ -1417,8 +1414,7 @@ func (m *certificateVerifyMsg) unmarshal(data []byte) bool { data = data[4:] if m.hasSignatureAndHash { - m.signatureAndHash.hash = data[0] - m.signatureAndHash.signature = data[1] + m.signatureAlgorithm = SignatureScheme(data[0])<<8 | SignatureScheme(data[1]) data = data[2:] } @@ -1554,13 +1550,12 @@ func eqByteSlices(x, y [][]byte) bool { return true } -func eqSignatureAndHashes(x, y []signatureAndHash) bool { +func eqSignatureAlgorithms(x, y []SignatureScheme) bool { if len(x) != len(y) { return false } for i, v := range x { - v2 := y[i] - if v.hash != v2.hash || v.signature != v2.signature { + if v != y[i] { return false } } diff --git a/handshake_messages_test.go b/handshake_messages_test.go index 49c13ee..aa7f937 100644 --- a/handshake_messages_test.go +++ b/handshake_messages_test.go @@ -145,7 +145,7 @@ func (*clientHelloMsg) Generate(rand *rand.Rand, size int) reflect.Value { } } if rand.Intn(10) > 5 { - m.signatureAndHashes = supportedSignatureAlgorithms + m.supportedSignatureAlgorithms = supportedSignatureAlgorithms } m.alpnProtocols = make([]string, rand.Intn(5)) for i := range m.alpnProtocols { diff --git a/handshake_server.go b/handshake_server.go index ae32848..991b4e9 100644 --- a/handshake_server.go +++ b/handshake_server.go @@ -418,7 +418,7 @@ func (hs *serverHandshakeState) doFullHandshake() error { } if c.vers >= VersionTLS12 { certReq.hasSignatureAndHash = true - certReq.signatureAndHashes = supportedSignatureAlgorithms + certReq.supportedSignatureAlgorithms = supportedSignatureAlgorithms } // An empty list of certificateAuthorities signals to @@ -519,27 +519,30 @@ func (hs *serverHandshakeState) doFullHandshake() error { } // Determine the signature type. - var signatureAndHash signatureAndHash + var signatureAlgorithm SignatureScheme + var sigType uint8 if certVerify.hasSignatureAndHash { - signatureAndHash = certVerify.signatureAndHash - if !isSupportedSignatureAndHash(signatureAndHash, supportedSignatureAlgorithms) { + signatureAlgorithm = certVerify.signatureAlgorithm + if !isSupportedSignatureAlgorithm(signatureAlgorithm, supportedSignatureAlgorithms) { return errors.New("tls: unsupported hash function for client certificate") } + sigType = signatureFromSignatureScheme(signatureAlgorithm) } else { // Before TLS 1.2 the signature algorithm was implicit // from the key type, and only one hash per signature - // algorithm was possible. Leave the hash as zero. + // algorithm was possible. Leave signatureAlgorithm + // unset. switch pub.(type) { case *ecdsa.PublicKey: - signatureAndHash.signature = signatureECDSA + sigType = signatureECDSA case *rsa.PublicKey: - signatureAndHash.signature = signatureRSA + sigType = signatureRSA } } switch key := pub.(type) { case *ecdsa.PublicKey: - if signatureAndHash.signature != signatureECDSA { + if sigType != signatureECDSA { err = errors.New("tls: bad signature type for client's ECDSA certificate") break } @@ -552,20 +555,20 @@ func (hs *serverHandshakeState) doFullHandshake() error { break } var digest []byte - if digest, _, err = hs.finishedHash.hashForClientCertificate(signatureAndHash, hs.masterSecret); err != nil { + if digest, _, err = hs.finishedHash.hashForClientCertificate(sigType, signatureAlgorithm, hs.masterSecret); err != nil { break } if !ecdsa.Verify(key, digest, ecdsaSig.R, ecdsaSig.S) { err = errors.New("tls: ECDSA verification failure") } case *rsa.PublicKey: - if signatureAndHash.signature != signatureRSA { + if sigType != signatureRSA { err = errors.New("tls: bad signature type for client's RSA certificate") break } var digest []byte var hashFunc crypto.Hash - if digest, hashFunc, err = hs.finishedHash.hashForClientCertificate(signatureAndHash, hs.masterSecret); err != nil { + if digest, hashFunc, err = hs.finishedHash.hashForClientCertificate(sigType, signatureAlgorithm, hs.masterSecret); err != nil { break } err = rsa.VerifyPKCS1v15(key, hashFunc, digest, certVerify.signature) @@ -818,17 +821,12 @@ func (hs *serverHandshakeState) clientHelloInfo() *ClientHelloInfo { supportedVersions = suppVersArray[VersionTLS12-hs.clientHello.vers:] } - signatureSchemes := make([]SignatureScheme, 0, len(hs.clientHello.signatureAndHashes)) - for _, sah := range hs.clientHello.signatureAndHashes { - signatureSchemes = append(signatureSchemes, SignatureScheme(sah.hash)<<8+SignatureScheme(sah.signature)) - } - hs.cachedClientHelloInfo = &ClientHelloInfo{ CipherSuites: hs.clientHello.cipherSuites, ServerName: hs.clientHello.serverName, SupportedCurves: hs.clientHello.supportedCurves, SupportedPoints: hs.clientHello.supportedPoints, - SignatureSchemes: signatureSchemes, + SignatureSchemes: hs.clientHello.supportedSignatureAlgorithms, SupportedProtos: hs.clientHello.alpnProtocols, SupportedVersions: supportedVersions, Conn: hs.c.conn, diff --git a/key_agreement.go b/key_agreement.go index 8edce74..3f570b6 100644 --- a/key_agreement.go +++ b/key_agreement.go @@ -110,14 +110,14 @@ func md5SHA1Hash(slices [][]byte) []byte { } // hashForServerKeyExchange hashes the given slices and returns their digest -// and the identifier of the hash function used. The sigAndHash argument is -// only used for >= TLS 1.2 and precisely identifies the hash function to use. -func hashForServerKeyExchange(sigAndHash signatureAndHash, version uint16, slices ...[]byte) ([]byte, crypto.Hash, error) { +// and the identifier of the hash function used. The signatureAlgorithm argument +// is only used for >= TLS 1.2 and identifies the hash function to use. +func hashForServerKeyExchange(sigType uint8, signatureAlgorithm SignatureScheme, version uint16, slices ...[]byte) ([]byte, crypto.Hash, error) { if version >= VersionTLS12 { - if !isSupportedSignatureAndHash(sigAndHash, supportedSignatureAlgorithms) { + if !isSupportedSignatureAlgorithm(signatureAlgorithm, supportedSignatureAlgorithms) { return nil, crypto.Hash(0), errors.New("tls: unsupported hash function used by peer") } - hashFunc, err := lookupTLSHash(sigAndHash.hash) + hashFunc, err := lookupTLSHash(signatureAlgorithm) if err != nil { return nil, crypto.Hash(0), err } @@ -128,7 +128,7 @@ func hashForServerKeyExchange(sigAndHash signatureAndHash, version uint16, slice digest := h.Sum(nil) return digest, hashFunc, nil } - if sigAndHash.signature == signatureECDSA { + if sigType == signatureECDSA { return sha1Hash(slices), crypto.SHA1, nil } return md5SHA1Hash(slices), crypto.MD5SHA1, nil @@ -137,20 +137,27 @@ func hashForServerKeyExchange(sigAndHash signatureAndHash, version uint16, slice // pickTLS12HashForSignature returns a TLS 1.2 hash identifier for signing a // ServerKeyExchange given the signature type being used and the client's // advertised list of supported signature and hash combinations. -func pickTLS12HashForSignature(sigType uint8, clientList []signatureAndHash) (uint8, error) { +func pickTLS12HashForSignature(sigType uint8, clientList []SignatureScheme) (SignatureScheme, error) { if len(clientList) == 0 { // If the client didn't specify any signature_algorithms // extension then we can assume that it supports SHA1. See // http://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 - return hashSHA1, nil + switch sigType { + case signatureRSA: + return PKCS1WithSHA1, nil + case signatureECDSA: + return ECDSAWithSHA1, nil + default: + return 0, errors.New("tls: unknown signature algorithm") + } } - for _, sigAndHash := range clientList { - if sigAndHash.signature != sigType { + for _, sigAlg := range clientList { + if signatureFromSignatureScheme(sigAlg) != sigType { continue } - if isSupportedSignatureAndHash(sigAndHash, supportedSignatureAlgorithms) { - return sigAndHash.hash, nil + if isSupportedSignatureAlgorithm(sigAlg, supportedSignatureAlgorithms) { + return sigAlg, nil } } @@ -240,16 +247,17 @@ NextCandidate: serverECDHParams[3] = byte(len(ecdhePublic)) copy(serverECDHParams[4:], ecdhePublic) - sigAndHash := signatureAndHash{signature: ka.sigType} + var signatureAlgorithm SignatureScheme if ka.version >= VersionTLS12 { var err error - if sigAndHash.hash, err = pickTLS12HashForSignature(ka.sigType, clientHello.signatureAndHashes); err != nil { + signatureAlgorithm, err = pickTLS12HashForSignature(ka.sigType, clientHello.supportedSignatureAlgorithms) + if err != nil { return nil, err } } - digest, hashFunc, err := hashForServerKeyExchange(sigAndHash, ka.version, clientHello.random, hello.random, serverECDHParams) + digest, hashFunc, err := hashForServerKeyExchange(ka.sigType, signatureAlgorithm, ka.version, clientHello.random, hello.random, serverECDHParams) if err != nil { return nil, err } @@ -287,8 +295,8 @@ NextCandidate: copy(skx.key, serverECDHParams) k := skx.key[len(serverECDHParams):] if ka.version >= VersionTLS12 { - k[0] = sigAndHash.hash - k[1] = sigAndHash.signature + k[0] = byte(signatureAlgorithm >> 8) + k[1] = byte(signatureAlgorithm) k = k[2:] } k[0] = byte(len(sig) >> 8) @@ -368,11 +376,11 @@ func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHell } } - sigAndHash := signatureAndHash{signature: ka.sigType} + var signatureAlgorithm SignatureScheme if ka.version >= VersionTLS12 { // handle SignatureAndHashAlgorithm - sigAndHash = signatureAndHash{hash: sig[0], signature: sig[1]} - if sigAndHash.signature != ka.sigType { + signatureAlgorithm = SignatureScheme(sig[0])<<8 | SignatureScheme(sig[1]) + if signatureFromSignatureScheme(signatureAlgorithm) != ka.sigType { return errServerKeyExchange } sig = sig[2:] @@ -386,7 +394,7 @@ func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHell } sig = sig[2:] - digest, hashFunc, err := hashForServerKeyExchange(sigAndHash, ka.version, clientHello.random, serverHello.random, serverECDHParams) + digest, hashFunc, err := hashForServerKeyExchange(ka.sigType, signatureAlgorithm, ka.version, clientHello.random, serverHello.random, serverECDHParams) if err != nil { return err } diff --git a/prf.go b/prf.go index 5833fc1..27a22f1 100644 --- a/prf.go +++ b/prf.go @@ -12,6 +12,7 @@ import ( "crypto/sha256" "crypto/sha512" "errors" + "fmt" "hash" ) @@ -180,17 +181,17 @@ func keysFromMasterSecret(version uint16, suite *cipherSuite, masterSecret, clie } // lookupTLSHash looks up the corresponding crypto.Hash for a given -// TLS hash identifier. -func lookupTLSHash(hash uint8) (crypto.Hash, error) { - switch hash { - case hashSHA1: +// hash from a TLS SignatureScheme. +func lookupTLSHash(signatureAlgorithm SignatureScheme) (crypto.Hash, error) { + switch signatureAlgorithm { + case PKCS1WithSHA1, ECDSAWithSHA1: return crypto.SHA1, nil - case hashSHA256: + case PKCS1WithSHA256, PSSWithSHA256, ECDSAWithP256AndSHA256: return crypto.SHA256, nil - case hashSHA384: + case PKCS1WithSHA384, PSSWithSHA384, ECDSAWithP384AndSHA384: return crypto.SHA384, nil default: - return 0, errors.New("tls: unsupported hash algorithm") + return 0, fmt.Errorf("tls: unsupported signature algorithm: %#04x", signatureAlgorithm) } } @@ -310,31 +311,26 @@ func (h finishedHash) serverSum(masterSecret []byte) []byte { return out } -// selectClientCertSignatureAlgorithm returns a signatureAndHash to sign a +// selectClientCertSignatureAlgorithm returns a SignatureScheme to sign a // client's CertificateVerify with, or an error if none can be found. -func (h finishedHash) selectClientCertSignatureAlgorithm(serverList []signatureAndHash, sigType uint8) (signatureAndHash, error) { - if h.version < VersionTLS12 { - // Nothing to negotiate before TLS 1.2. - return signatureAndHash{signature: sigType}, nil - } - +func (h finishedHash) selectClientCertSignatureAlgorithm(serverList []SignatureScheme, sigType uint8) (SignatureScheme, error) { for _, v := range serverList { - if v.signature == sigType && isSupportedSignatureAndHash(v, supportedSignatureAlgorithms) { + if signatureFromSignatureScheme(v) == sigType && isSupportedSignatureAlgorithm(v, supportedSignatureAlgorithms) { return v, nil } } - return signatureAndHash{}, errors.New("tls: no supported signature algorithm found for signing client certificate") + return 0, errors.New("tls: no supported signature algorithm found for signing client certificate") } // hashForClientCertificate returns a digest, hash function, and TLS 1.2 hash // id suitable for signing by a TLS client certificate. -func (h finishedHash) hashForClientCertificate(signatureAndHash signatureAndHash, masterSecret []byte) ([]byte, crypto.Hash, error) { +func (h finishedHash) hashForClientCertificate(sigType uint8, signatureAlgorithm SignatureScheme, masterSecret []byte) ([]byte, crypto.Hash, error) { if (h.version == VersionSSL30 || h.version >= VersionTLS12) && h.buffer == nil { panic("a handshake hash for a client-certificate was requested after discarding the handshake buffer") } if h.version == VersionSSL30 { - if signatureAndHash.signature != signatureRSA { + if sigType != signatureRSA { return nil, 0, errors.New("tls: unsupported signature type for client certificate") } @@ -345,7 +341,7 @@ func (h finishedHash) hashForClientCertificate(signatureAndHash signatureAndHash return finishedSum30(md5Hash, sha1Hash, masterSecret, nil), crypto.MD5SHA1, nil } if h.version >= VersionTLS12 { - hashAlg, err := lookupTLSHash(signatureAndHash.hash) + hashAlg, err := lookupTLSHash(signatureAlgorithm) if err != nil { return nil, 0, err } @@ -354,7 +350,7 @@ func (h finishedHash) hashForClientCertificate(signatureAndHash signatureAndHash return hash.Sum(nil), hashAlg, nil } - if signatureAndHash.signature == signatureECDSA { + if sigType == signatureECDSA { return h.server.Sum(nil), crypto.SHA1, nil }