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Refactor the keyAgreement interface

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It's sufficient to pass in the *tls.Certificate (resp.
*x509.Certificate) to the server functions (resp. client funcctions),
but not necessary; the existing keyAgreement implementations only makes
use of the private key (resp. public key). Moreover, this change is
necessary for implementing the delegated credentials extension, which
replaces the private key (resp. public key) used in the handshake.
This commit is contained in:
Christopher Patton 2018-06-21 09:34:19 -07:00
parent 3ff71dcdc5
commit 963d5877be
4 changed files with 22 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
cipher_suites.go
View File

@ -5,6 +5,7 @@
package tls
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"crypto/des"
@ -12,7 +13,6 @@ import (
"crypto/rc4"
"crypto/sha1"
"crypto/sha256"
"crypto/x509"
"hash"
"golang_org/x/crypto/chacha20poly1305"
@ -26,15 +26,15 @@ type keyAgreement interface {
// In the case that the key agreement protocol doesn't use a
// ServerKeyExchange message, generateServerKeyExchange can return nil,
// nil.
generateServerKeyExchange(*Config, *Certificate, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
processClientKeyExchange(*Config, *Certificate, *clientKeyExchangeMsg, uint16) ([]byte, error)
generateServerKeyExchange(*Config, crypto.PrivateKey, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, error)
processClientKeyExchange(*Config, crypto.PrivateKey, *clientKeyExchangeMsg, uint16) ([]byte, error)
// On the client side, the next two methods are called in order.
// This method may not be called if the server doesn't send a
// ServerKeyExchange message.
processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) error
generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error)
processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, crypto.PublicKey, *serverKeyExchangeMsg) error
generateClientKeyExchange(*Config, *clientHelloMsg, crypto.PublicKey) ([]byte, *clientKeyExchangeMsg, error)
}
const (

4
handshake_client.go
View File

@ -480,7 +480,7 @@ func (hs *clientHandshakeState) doFullHandshake() error {
skx, ok := msg.(*serverKeyExchangeMsg)
if ok {
hs.finishedHash.Write(skx.marshal())
err = keyAgreement.processServerKeyExchange(c.config, hs.hello, hs.serverHello, c.peerCertificates[0], skx)
err = keyAgreement.processServerKeyExchange(c.config, hs.hello, hs.serverHello, c.peerCertificates[0].PublicKey, skx)
if err != nil {
c.sendAlert(alertUnexpectedMessage)
return err
@ -529,7 +529,7 @@ func (hs *clientHandshakeState) doFullHandshake() error {
}
}
preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.hello, c.peerCertificates[0])
preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.hello, c.peerCertificates[0].PublicKey)
if err != nil {
c.sendAlert(alertInternalError)
return err

4
handshake_server.go
View File

@ -479,7 +479,7 @@ func (hs *serverHandshakeState) doFullHandshake() error {
}
keyAgreement := hs.suite.ka(c.vers)
skx, err := keyAgreement.generateServerKeyExchange(c.config, hs.cert, hs.clientHello, hs.hello)
skx, err := keyAgreement.generateServerKeyExchange(c.config, hs.cert.PrivateKey, hs.clientHello, hs.hello)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
@ -572,7 +572,7 @@ func (hs *serverHandshakeState) doFullHandshake() error {
}
hs.finishedHash.Write(ckx.marshal())
preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert, ckx, c.vers)
preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert.PrivateKey, ckx, c.vers)
if err != nil {
if err == errClientKeyExchange {
c.sendAlert(alertDecodeError)

27
key_agreement.go
View File

@ -10,7 +10,6 @@ import (
"crypto/md5"
"crypto/rsa"
"crypto/sha1"
"crypto/x509"
"errors"
"io"
"math/big"
@ -25,11 +24,11 @@ var errServerKeyExchange = errors.New("tls: invalid ServerKeyExchange message")
// encrypts the pre-master secret to the server's public key.
type rsaKeyAgreement struct{}
func (ka rsaKeyAgreement) generateServerKeyExchange(config *Config, cert *Certificate, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
func (ka rsaKeyAgreement) generateServerKeyExchange(config *Config, sk crypto.PrivateKey, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
return nil, nil
}
func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, cert *Certificate, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, sk crypto.PrivateKey, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
if len(ckx.ciphertext) < 2 {
return nil, errClientKeyExchange
}
@ -42,7 +41,7 @@ func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, cert *Certifi
}
ciphertext = ckx.ciphertext[2:]
}
priv, ok := cert.PrivateKey.(crypto.Decrypter)
priv, ok := sk.(crypto.Decrypter)
if !ok {
return nil, errors.New("tls: certificate private key does not implement crypto.Decrypter")
}
@ -60,11 +59,11 @@ func (ka rsaKeyAgreement) processClientKeyExchange(config *Config, cert *Certifi
return preMasterSecret, nil
}
func (ka rsaKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) error {
func (ka rsaKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, pk crypto.PublicKey, skx *serverKeyExchangeMsg) error {
return errors.New("tls: unexpected ServerKeyExchange")
}
func (ka rsaKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error) {
func (ka rsaKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, pk crypto.PublicKey) ([]byte, *clientKeyExchangeMsg, error) {
preMasterSecret := make([]byte, 48)
preMasterSecret[0] = byte(clientHello.vers >> 8)
preMasterSecret[1] = byte(clientHello.vers)
@ -73,7 +72,7 @@ func (ka rsaKeyAgreement) generateClientKeyExchange(config *Config, clientHello
return nil, nil, err
}
encrypted, err := rsa.EncryptPKCS1v15(config.rand(), cert.PublicKey.(*rsa.PublicKey), preMasterSecret)
encrypted, err := rsa.EncryptPKCS1v15(config.rand(), pk.(*rsa.PublicKey), preMasterSecret)
if err != nil {
return nil, nil, err
}
@ -156,7 +155,7 @@ type ecdheKeyAgreement struct {
x, y *big.Int
}
func (ka *ecdheKeyAgreement) generateServerKeyExchange(config *Config, cert *Certificate, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
func (ka *ecdheKeyAgreement) generateServerKeyExchange(config *Config, sk crypto.PrivateKey, clientHello *clientHelloMsg, hello *serverHelloMsg) (*serverKeyExchangeMsg, error) {
preferredCurves := config.curvePreferences()
NextCandidate:
@ -207,7 +206,7 @@ NextCandidate:
serverECDHParams[3] = byte(len(ecdhePublic))
copy(serverECDHParams[4:], ecdhePublic)
priv, ok := cert.PrivateKey.(crypto.Signer)
priv, ok := sk.(crypto.Signer)
if !ok {
return nil, errors.New("tls: certificate private key does not implement crypto.Signer")
}
@ -255,7 +254,7 @@ NextCandidate:
return skx, nil
}
func (ka *ecdheKeyAgreement) processClientKeyExchange(config *Config, cert *Certificate, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
func (ka *ecdheKeyAgreement) processClientKeyExchange(config *Config, sk crypto.PrivateKey, ckx *clientKeyExchangeMsg, version uint16) ([]byte, error) {
if len(ckx.ciphertext) == 0 || int(ckx.ciphertext[0]) != len(ckx.ciphertext)-1 {
return nil, errClientKeyExchange
}
@ -291,7 +290,7 @@ func (ka *ecdheKeyAgreement) processClientKeyExchange(config *Config, cert *Cert
return preMasterSecret, nil
}
func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, cert *x509.Certificate, skx *serverKeyExchangeMsg) error {
func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHello *clientHelloMsg, serverHello *serverHelloMsg, pk crypto.PublicKey, skx *serverKeyExchangeMsg) error {
if len(skx.key) < 4 {
return errServerKeyExchange
}
@ -337,7 +336,7 @@ func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHell
return errServerKeyExchange
}
}
_, sigType, hashFunc, err := pickSignatureAlgorithm(cert.PublicKey, []SignatureScheme{signatureAlgorithm}, clientHello.supportedSignatureAlgorithms, ka.version)
_, sigType, hashFunc, err := pickSignatureAlgorithm(pk, []SignatureScheme{signatureAlgorithm}, clientHello.supportedSignatureAlgorithms, ka.version)
if err != nil {
return err
}
@ -355,10 +354,10 @@ func (ka *ecdheKeyAgreement) processServerKeyExchange(config *Config, clientHell
if err != nil {
return err
}
return verifyHandshakeSignature(sigType, cert.PublicKey, hashFunc, digest, sig)
return verifyHandshakeSignature(sigType, pk, hashFunc, digest, sig)
}
func (ka *ecdheKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, cert *x509.Certificate) ([]byte, *clientKeyExchangeMsg, error) {
func (ka *ecdheKeyAgreement) generateClientKeyExchange(config *Config, clientHello *clientHelloMsg, pk crypto.PublicKey) ([]byte, *clientKeyExchangeMsg, error) {
if ka.curveid == 0 {
return nil, nil, errors.New("tls: missing ServerKeyExchange message")
}