[WIP] Upgrade TLS1.2 to TLS1.3

go.mod

@@ -25,8 +25,9 @@ require (
 	github.com/ziutek/mymysql v1.5.4 // indirect
 	github.com/zmap/zcrypto v0.0.0-20191112190257-7f2fe6faf8cf
 	github.com/zmap/zlint/v2 v2.0.0
-	golang.org/x/crypto v0.0.0-20200124225646-8b5121be2f68
+	golang.org/x/crypto v0.0.0-20200420201142-3c4aac89819a
 	golang.org/x/lint v0.0.0-20190930215403-16217165b5de
 	golang.org/x/net v0.0.0-20190620200207-3b0461eec859
+	golang.org/x/sys v0.0.0-20200420163511-1957bb5e6d1f
 	golang.org/x/text v0.3.2 // indirect
 )

go.sum

@@ -84,6 +84,8 @@ golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4 h1:HuIa8hRrWRSrqYzx1qI49N
 golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200124225646-8b5121be2f68 h1:WPLCzSEbawp58wezcvLvLnvhiDJAai54ESbc41NdXS0=
 golang.org/x/crypto v0.0.0-20200124225646-8b5121be2f68/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20200420201142-3c4aac89819a h1:y6sBfNd1b9Wy08a6K1Z1DZc4aXABUN5TKjkYhz7UKmo=
+golang.org/x/crypto v0.0.0-20200420201142-3c4aac89819a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -93,7 +95,10 @@ golang.org/x/net v0.0.0-20190620200207-3b0461eec859 h1:R/3boaszxrf1GEUWTVDzSKVwL
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200420163511-1957bb5e6d1f h1:gWF768j/LaZugp8dyS4UwsslYCYz9XgFxvlgsn0n9H8=
+golang.org/x/sys v0.0.0-20200420163511-1957bb5e6d1f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=

scan/crypto/tls/alert.go

@@ -38,6 +38,10 @@ const (
 	alertInappropriateFallback  alert = 86
 	alertUserCanceled           alert = 90
 	alertNoRenegotiation        alert = 100
+	alertMissingExtension       alert = 109
+	alertUnsupportedExtension   alert = 110
+	alertUnrecognizedName       alert = 112
+	alertNoApplicationProtocol  alert = 120
 )
 
 var alertText = map[alert]string{
@@ -64,14 +68,18 @@ var alertText = map[alert]string{
 	alertInappropriateFallback:  "inappropriate fallback",
 	alertUserCanceled:           "user canceled",
 	alertNoRenegotiation:        "no renegotiation",
+	alertMissingExtension:       "missing extension",
+	alertUnsupportedExtension:   "unsupported extension",
+	alertUnrecognizedName:       "unrecognized name",
+	alertNoApplicationProtocol:  "no application protocol",
 }
 
 func (e alert) String() string {
 	s, ok := alertText[e]
 	if ok {
-		return s
+		return "tls: " + s
 	}
-	return "alert(" + strconv.Itoa(int(e)) + ")"
+	return "tls: alert(" + strconv.Itoa(int(e)) + ")"
 }
 
 func (e alert) Error() string {

scan/crypto/tls/auth.go

@@ -0,0 +1,298 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tls
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rsa"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+	"hash"
+	"io"
+
+	"golang.org/x/crypto/ed25519"
+)
+
+// verifyHandshakeSignature verifies a signature against pre-hashed
+// (if required) handshake contents.
+func verifyHandshakeSignature(sigType uint8, pubkey crypto.PublicKey, hashFunc crypto.Hash, signed, 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)
+		}
+		ecdsaSig := new(ecdsaSignature)
+		if _, err := asn1.Unmarshal(sig, ecdsaSig); err != nil {
+			return err
+		}
+		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
+			return errors.New("ECDSA signature contained zero or negative values")
+		}
+		if !ecdsa.Verify(pubKey, signed, ecdsaSig.R, ecdsaSig.S) {
+			return errors.New("ECDSA verification failure")
+		}
+	case signatureEd25519:
+		pubKey, ok := pubkey.(ed25519.PublicKey)
+		if !ok {
+			return fmt.Errorf("expected an Ed25519 public key, got %T", pubkey)
+		}
+		if !ed25519.Verify(pubKey, signed, sig) {
+			return errors.New("Ed25519 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, signed, sig); err != nil {
+			return err
+		}
+	case signatureRSAPSS:
+		pubKey, ok := pubkey.(*rsa.PublicKey)
+		if !ok {
+			return fmt.Errorf("expected an RSA public key, got %T", pubkey)
+		}
+		signOpts := &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash}
+		if err := rsa.VerifyPSS(pubKey, hashFunc, signed, sig, signOpts); 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"
+)
+
+var signaturePadding = []byte{
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	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)
+}
+
+// typeAndHashFromSignatureScheme returns the corresponding signature type and
+// crypto.Hash for a given TLS SignatureScheme.
+func typeAndHashFromSignatureScheme(signatureAlgorithm SignatureScheme) (sigType uint8, hash crypto.Hash, err error) {
+	switch signatureAlgorithm {
+	case PKCS1WithSHA1, PKCS1WithSHA256, PKCS1WithSHA384, PKCS1WithSHA512:
+		sigType = signaturePKCS1v15
+	case PSSWithSHA256, PSSWithSHA384, PSSWithSHA512:
+		sigType = signatureRSAPSS
+	case ECDSAWithSHA1, ECDSAWithP256AndSHA256, ECDSAWithP384AndSHA384, ECDSAWithP521AndSHA512:
+		sigType = signatureECDSA
+	case Ed25519:
+		sigType = signatureEd25519
+	default:
+		return 0, 0, fmt.Errorf("unsupported signature algorithm: %#04x", signatureAlgorithm)
+	}
+	switch signatureAlgorithm {
+	case PKCS1WithSHA1, ECDSAWithSHA1:
+		hash = crypto.SHA1
+	case PKCS1WithSHA256, PSSWithSHA256, ECDSAWithP256AndSHA256:
+		hash = crypto.SHA256
+	case PKCS1WithSHA384, PSSWithSHA384, ECDSAWithP384AndSHA384:
+		hash = crypto.SHA384
+	case PKCS1WithSHA512, PSSWithSHA512, ECDSAWithP521AndSHA512:
+		hash = crypto.SHA512
+	case Ed25519:
+		hash = directSigning
+	default:
+		return 0, 0, fmt.Errorf("unsupported signature algorithm: %#04x", signatureAlgorithm)
+	}
+	return sigType, hash, nil
+}
+
+// legacyTypeAndHashFromPublicKey returns the fixed signature type and crypto.Hash for
+// a given public key used with TLS 1.0 and 1.1, before the introduction of
+// signature algorithm negotiation.
+func legacyTypeAndHashFromPublicKey(pub crypto.PublicKey) (sigType uint8, hash crypto.Hash, err error) {
+	switch pub.(type) {
+	case *rsa.PublicKey:
+		return signaturePKCS1v15, crypto.MD5SHA1, nil
+	case *ecdsa.PublicKey:
+		return signatureECDSA, crypto.SHA1, nil
+	case ed25519.PublicKey:
+		// RFC 8422 specifies support for Ed25519 in TLS 1.0 and 1.1,
+		// but it requires holding on to a handshake transcript to do a
+		// full signature, and not even OpenSSL bothers with the
+		// complexity, so we can't even test it properly.
+		return 0, 0, fmt.Errorf("tls: Ed25519 public keys are not supported before TLS 1.2")
+	default:
+		return 0, 0, fmt.Errorf("tls: unsupported public key: %T", pub)
+	}
+}
+
+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},
+	// 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},
+}
+
+// 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.
+//
+// This function must be kept in sync with 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) {
+	case *ecdsa.PublicKey:
+		if version != VersionTLS13 {
+			// In TLS 1.2 and earlier, ECDSA algorithms are not
+			// constrained to a single curve.
+			sigAlgs = []SignatureScheme{
+				ECDSAWithP256AndSHA256,
+				ECDSAWithP384AndSHA384,
+				ECDSAWithP521AndSHA512,
+				ECDSAWithSHA1,
+			}
+			break
+		}
+		switch pub.Curve {
+		case elliptic.P256():
+			sigAlgs = []SignatureScheme{ECDSAWithP256AndSHA256}
+		case elliptic.P384():
+			sigAlgs = []SignatureScheme{ECDSAWithP384AndSHA384}
+		case elliptic.P521():
+			sigAlgs = []SignatureScheme{ECDSAWithP521AndSHA512}
+		default:
+			return nil
+		}
+	case *rsa.PublicKey:
+		size := pub.Size()
+		sigAlgs = make([]SignatureScheme, 0, len(rsaSignatureSchemes))
+		for _, candidate := range rsaSignatureSchemes {
+			if size >= candidate.minModulusBytes && version <= candidate.maxVersion {
+				sigAlgs = append(sigAlgs, candidate.scheme)
+			}
+		}
+	case ed25519.PublicKey:
+		sigAlgs = []SignatureScheme{Ed25519}
+	default:
+		return nil
+	}
+
+	if cert.SupportedSignatureAlgorithms != nil {
+		var filteredSigAlgs []SignatureScheme
+		for _, sigAlg := range sigAlgs {
+			if isSupportedSignatureAlgorithm(sigAlg, cert.SupportedSignatureAlgorithms) {
+				filteredSigAlgs = append(filteredSigAlgs, sigAlg)
+			}
+		}
+		return filteredSigAlgs
+	}
+	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)
+	if len(supportedAlgs) == 0 {
+		return 0, unsupportedCertificateError(c)
+	}
+	if len(peerAlgs) == 0 && vers == VersionTLS12 {
+		// For TLS 1.2, if the client didn't send signature_algorithms then we
+		// can assume that it supports SHA1. See RFC 5246, Section 7.4.1.4.1.
+		peerAlgs = []SignatureScheme{PKCS1WithSHA1, ECDSAWithSHA1}
+	}
+	// Pick signature scheme in the peer's preference order, as our
+	// preference order is not configurable.
+	for _, preferredAlg := range peerAlgs {
+		if isSupportedSignatureAlgorithm(preferredAlg, supportedAlgs) {
+			return preferredAlg, nil
+		}
+	}
+	return 0, errors.New("tls: peer doesn't support any of the certificate's signature algorithms")
+}
+
+// unsupportedCertificateError returns a helpful error for certificates with
+// an unsupported private key.
+func unsupportedCertificateError(cert *Certificate) error {
+	switch cert.PrivateKey.(type) {
+	case rsa.PrivateKey, ecdsa.PrivateKey:
+		return fmt.Errorf("tls: unsupported certificate: private key is %T, expected *%T",
+			cert.PrivateKey, cert.PrivateKey)
+	case *ed25519.PrivateKey:
+		return fmt.Errorf("tls: unsupported certificate: private key is *ed25519.PrivateKey, expected ed25519.PrivateKey")
+	}
+
+	signer, ok := cert.PrivateKey.(crypto.Signer)
+	if !ok {
+		return fmt.Errorf("tls: certificate private key (%T) does not implement crypto.Signer",
+			cert.PrivateKey)
+	}
+
+	switch pub := signer.Public().(type) {
+	case *ecdsa.PublicKey:
+		switch pub.Curve {
+		case elliptic.P256():
+		case elliptic.P384():
+		case elliptic.P521():
+		default:
+			return fmt.Errorf("tls: unsupported certificate curve (%s)", pub.Curve.Params().Name)
+		}
+	case *rsa.PublicKey:
+		return fmt.Errorf("tls: certificate RSA key size too small for supported signature algorithms")
+	case ed25519.PublicKey:
+	default:
+		return fmt.Errorf("tls: unsupported certificate key (%T)", pub)
+	}
+
+	if cert.SupportedSignatureAlgorithms != nil {
+		return fmt.Errorf("tls: peer doesn't support the certificate custom signature algorithms")
+	}
+
+	return fmt.Errorf("tls: internal error: unsupported key (%T)", cert.PrivateKey)
+}