Yearly update to latest go

auth.go

@@ -18,9 +18,13 @@ import (
 	"slices"
 )
 
-// verifyHandshakeSignature verifies a signature against pre-hashed
-// (if required) handshake contents.
+// verifyHandshakeSignature verifies a signature against unhashed handshake contents.
 func verifyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, signed, sig []byte) error {
+	if hashFunc != directSigning {
+		h := hashFunc.New()
+		h.Write(signed)
+		signed = h.Sum(nil)
+	}
 	switch sigType {
 	case signatureECDSA:
 		pubKey, ok := pubkey.(*ecdsa.PublicKey)
@@ -61,6 +65,32 @@ func verifyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc c
 	return nil
 }
 
+// verifyLegacyHandshakeSignature verifies a TLS 1.0 and 1.1 signature against
+// pre-hashed handshake contents.
+func verifyLegacyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, hashed, sig []byte) error {
+	switch sigType {
+	case signatureECDSA:
+		pubKey, ok := pubkey.(*ecdsa.PublicKey)
+		if !ok {
+			return fmt.Errorf("expected an ECDSA public key, got %T", pubkey)
+		}
+		if !ecdsa.VerifyASN1(pubKey, hashed, sig) {
+			return errors.New("ECDSA verification failure")
+		}
+	case signaturePKCS1v15:
+		pubKey, ok := pubkey.(*rsa.PublicKey)
+		if !ok {
+			return fmt.Errorf("expected an RSA public key, got %T", pubkey)
+		}
+		if err := rsa.VerifyPKCS1v15(pubKey, hashFunc, hashed, sig); err != nil {
+			return err
+		}
+	default:
+		return errors.New("internal error: unknown signature type")
+	}
+	return nil
+}
+
 const (
 	serverSignatureContext = "TLS 1.3, server CertificateVerify\x00"
 	clientSignatureContext = "TLS 1.3, client CertificateVerify\x00"
@@ -77,21 +107,15 @@ var signaturePadding = []byte{
 	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
 }
 
-// signedMessage returns the pre-hashed (if necessary) message to be signed by
-// certificate keys in TLS 1.3. See RFC 8446, Section 4.4.3.
-func signedMessage(sigHash crypto.Hash, context string, transcript hash.Hash) []byte {
-	if sigHash == directSigning {
-		b := &bytes.Buffer{}
-		b.Write(signaturePadding)
-		io.WriteString(b, context)
-		b.Write(transcript.Sum(nil))
-		return b.Bytes()
-	}
-	h := sigHash.New()
-	h.Write(signaturePadding)
-	io.WriteString(h, context)
-	h.Write(transcript.Sum(nil))
-	return h.Sum(nil)
+// signedMessage returns the (unhashed) message to be signed by certificate keys
+// in TLS 1.3. See RFC 8446, Section 4.4.3.
+func signedMessage(context string, transcript hash.Hash) []byte {
+	const maxSize = 64 /* signaturePadding */ + len(serverSignatureContext) + 512/8 /* SHA-512 */
+	b := bytes.NewBuffer(make([]byte, 0, maxSize))
+	b.Write(signaturePadding)
+	io.WriteString(b, context)
+	b.Write(transcript.Sum(nil))
+	return b.Bytes()
 }
 
 // typeAndHashFromSignatureScheme returns the corresponding signature type and
@@ -149,90 +173,78 @@ func legacyTypeAndHashFromPublicKey(pub crypto.PublicKey) (sigType uint8, hash c
 var rsaSignatureSchemes = []struct {
 	scheme          SignatureScheme
 	minModulusBytes int
-	maxVersion      uint16
 }{
 	// RSA-PSS is used with PSSSaltLengthEqualsHash, and requires
 	//    emLen >= hLen + sLen + 2
-	{PSSWithSHA256, crypto.SHA256.Size()*2 + 2, VersionTLS13},
-	{PSSWithSHA384, crypto.SHA384.Size()*2 + 2, VersionTLS13},
-	{PSSWithSHA512, crypto.SHA512.Size()*2 + 2, VersionTLS13},
+	{PSSWithSHA256, crypto.SHA256.Size()*2 + 2},
+	{PSSWithSHA384, crypto.SHA384.Size()*2 + 2},
+	{PSSWithSHA512, crypto.SHA512.Size()*2 + 2},
 	// PKCS #1 v1.5 uses prefixes from hashPrefixes in crypto/rsa, and requires
 	//    emLen >= len(prefix) + hLen + 11
-	// TLS 1.3 dropped support for PKCS #1 v1.5 in favor of RSA-PSS.
-	{PKCS1WithSHA256, 19 + crypto.SHA256.Size() + 11, VersionTLS12},
-	{PKCS1WithSHA384, 19 + crypto.SHA384.Size() + 11, VersionTLS12},
-	{PKCS1WithSHA512, 19 + crypto.SHA512.Size() + 11, VersionTLS12},
-	{PKCS1WithSHA1, 15 + crypto.SHA1.Size() + 11, VersionTLS12},
+	{PKCS1WithSHA256, 19 + crypto.SHA256.Size() + 11},
+	{PKCS1WithSHA384, 19 + crypto.SHA384.Size() + 11},
+	{PKCS1WithSHA512, 19 + crypto.SHA512.Size() + 11},
+	{PKCS1WithSHA1, 15 + crypto.SHA1.Size() + 11},
 }
 
-// signatureSchemesForCertificate returns the list of supported SignatureSchemes
-// for a given certificate, based on the public key and the protocol version,
-// and optionally filtered by its explicit SupportedSignatureAlgorithms.
-func signatureSchemesForCertificate(version uint16, cert *Certificate) []SignatureScheme {
-	priv, ok := cert.PrivateKey.(crypto.Signer)
-	if !ok {
-		return nil
-	}
-
-	var sigAlgs []SignatureScheme
-	switch pub := priv.Public().(type) {
+func signatureSchemesForPublicKey(version uint16, pub crypto.PublicKey) []SignatureScheme {
+	switch pub := pub.(type) {
 	case *ecdsa.PublicKey:
-		if version != VersionTLS13 {
+		if version < VersionTLS13 {
 			// In TLS 1.2 and earlier, ECDSA algorithms are not
 			// constrained to a single curve.
-			sigAlgs = []SignatureScheme{
+			return []SignatureScheme{
 				ECDSAWithP256AndSHA256,
 				ECDSAWithP384AndSHA384,
 				ECDSAWithP521AndSHA512,
 				ECDSAWithSHA1,
 			}
-			break
 		}
 		switch pub.Curve {
 		case elliptic.P256():
-			sigAlgs = []SignatureScheme{ECDSAWithP256AndSHA256}
+			return []SignatureScheme{ECDSAWithP256AndSHA256}
 		case elliptic.P384():
-			sigAlgs = []SignatureScheme{ECDSAWithP384AndSHA384}
+			return []SignatureScheme{ECDSAWithP384AndSHA384}
 		case elliptic.P521():
-			sigAlgs = []SignatureScheme{ECDSAWithP521AndSHA512}
+			return []SignatureScheme{ECDSAWithP521AndSHA512}
 		default:
 			return nil
 		}
 	case *rsa.PublicKey:
 		size := pub.Size()
-		sigAlgs = make([]SignatureScheme, 0, len(rsaSignatureSchemes))
+		sigAlgs := make([]SignatureScheme, 0, len(rsaSignatureSchemes))
 		for _, candidate := range rsaSignatureSchemes {
-			if size >= candidate.minModulusBytes && version <= candidate.maxVersion {
+			if size >= candidate.minModulusBytes {
 				sigAlgs = append(sigAlgs, candidate.scheme)
 			}
 		}
+		return sigAlgs
 	case ed25519.PublicKey:
-		sigAlgs = []SignatureScheme{Ed25519}
+		return []SignatureScheme{Ed25519}
 	default:
 		return nil
 	}
-
-	if cert.SupportedSignatureAlgorithms != nil {
-		sigAlgs = slices.DeleteFunc(sigAlgs, func(sigAlg SignatureScheme) bool {
-			return !isSupportedSignatureAlgorithm(sigAlg, cert.SupportedSignatureAlgorithms)
-		})
-	}
-
-	// Filter out any unsupported signature algorithms, for example due to
-	// FIPS 140-3 policy, tlssha1=0, or any downstream changes to defaults.go.
-	supportedAlgs := supportedSignatureAlgorithms(version)
-	sigAlgs = slices.DeleteFunc(sigAlgs, func(sigAlg SignatureScheme) bool {
-		return !isSupportedSignatureAlgorithm(sigAlg, supportedAlgs)
-	})
-
-	return sigAlgs
 }
 
 // selectSignatureScheme picks a SignatureScheme from the peer's preference list
 // that works with the selected certificate. It's only called for protocol
 // versions that support signature algorithms, so TLS 1.2 and 1.3.
 func selectSignatureScheme(vers uint16, c *Certificate, peerAlgs []SignatureScheme) (SignatureScheme, error) {
-	supportedAlgs := signatureSchemesForCertificate(vers, c)
+	priv, ok := c.PrivateKey.(crypto.Signer)
+	if !ok {
+		return 0, unsupportedCertificateError(c)
+	}
+	supportedAlgs := signatureSchemesForPublicKey(vers, priv.Public())
+	if c.SupportedSignatureAlgorithms != nil {
+		supportedAlgs = slices.DeleteFunc(supportedAlgs, func(sigAlg SignatureScheme) bool {
+			return !isSupportedSignatureAlgorithm(sigAlg, c.SupportedSignatureAlgorithms)
+		})
+	}
+	// Filter out any unsupported signature algorithms, for example due to
+	// FIPS 140-3 policy, tlssha1=0, or protocol version.
+	supportedAlgs = slices.DeleteFunc(supportedAlgs, func(sigAlg SignatureScheme) bool {
+		return isDisabledSignatureAlgorithm(vers, sigAlg, false)
+	})
 	if len(supportedAlgs) == 0 {
 		return 0, unsupportedCertificateError(c)
 	}

cipher_suites.go

@@ -146,8 +146,8 @@ type cipherSuite struct {
 }
 
 var cipherSuites = []*cipherSuite{ // TODO: replace with a map, since the order doesn't matter.
-	{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
-	{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
+	{TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 32, 0, 12, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
+	{TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 32, 0, 12, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadChaCha20Poly1305},
 	{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12, nil, nil, aeadAESGCM},
 	{TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, 16, 0, 4, ecdheECDSAKA, suiteECDHE | suiteECSign | suiteTLS12, nil, nil, aeadAESGCM},
 	{TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 32, 0, 4, ecdheRSAKA, suiteECDHE | suiteTLS12 | suiteSHA384, nil, nil, aeadAESGCM},
@@ -281,7 +281,7 @@ var cipherSuitesPreferenceOrder = []uint16{
 	// AEADs w/ ECDHE
 	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
 	TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
-	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
 
 	// CBC w/ ECDHE
 	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
@@ -310,7 +310,7 @@ var cipherSuitesPreferenceOrder = []uint16{
 
 var cipherSuitesPreferenceOrderNoAES = []uint16{
 	// ChaCha20Poly1305
-	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
 
 	// AES-GCM w/ ECDHE
 	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,