954c3ec034
(ECDHE is "Elliptic Curve Diffie Hellman Ephemeral") R=rsc CC=golang-dev https://golang.org/cl/3668042
103 lines
3.4 KiB
Go
103 lines
3.4 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package tls
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/hmac"
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"crypto/rc4"
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"crypto/x509"
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"hash"
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"os"
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)
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// a keyAgreement implements the client and server side of a TLS key agreement
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// protocol by generating and processing key exchange messages.
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type keyAgreement interface {
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// On the server side, the first two methods are called in order.
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// In the case that the key agreement protocol doesn't use a
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// ServerKeyExchange message, generateServerKeyExchange can return nil,
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// nil.
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generateServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg) (*serverKeyExchangeMsg, os.Error)
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processClientKeyExchange(*Config, *clientKeyExchangeMsg) ([]byte, os.Error)
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// On the client side, the next two methods are called in order.
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// This method may not be called if the server doesn't send a
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// ServerKeyExchange message.
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processServerKeyExchange(*Config, *clientHelloMsg, *serverHelloMsg, *x509.Certificate, *serverKeyExchangeMsg) os.Error
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generateClientKeyExchange(*Config, *clientHelloMsg, *x509.Certificate) ([]byte, *clientKeyExchangeMsg, os.Error)
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}
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// A cipherSuite is a specific combination of key agreement, cipher and MAC
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// function. All cipher suites currently assume RSA key agreement.
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type cipherSuite struct {
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// the lengths, in bytes, of the key material needed for each component.
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keyLen int
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macLen int
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ivLen int
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ka func() keyAgreement
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// If elliptic is set, a server will only consider this ciphersuite if
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// the ClientHello indicated that the client supports an elliptic curve
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// and point format that we can handle.
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elliptic bool
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cipher func(key, iv []byte, isRead bool) interface{}
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mac func(macKey []byte) hash.Hash
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}
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var cipherSuites = map[uint16]*cipherSuite{
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TLS_RSA_WITH_RC4_128_SHA: &cipherSuite{16, 20, 0, rsaKA, false, cipherRC4, hmacSHA1},
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TLS_RSA_WITH_AES_128_CBC_SHA: &cipherSuite{16, 20, 16, rsaKA, false, cipherAES, hmacSHA1},
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TLS_ECDHE_RSA_WITH_RC4_128_SHA: &cipherSuite{16, 20, 0, ecdheRSAKA, true, cipherRC4, hmacSHA1},
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TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA: &cipherSuite{16, 20, 16, ecdheRSAKA, true, cipherAES, hmacSHA1},
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}
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func cipherRC4(key, iv []byte, isRead bool) interface{} {
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cipher, _ := rc4.NewCipher(key)
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return cipher
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}
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func cipherAES(key, iv []byte, isRead bool) interface{} {
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block, _ := aes.NewCipher(key)
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if isRead {
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return cipher.NewCBCDecrypter(block, iv)
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}
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return cipher.NewCBCEncrypter(block, iv)
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}
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func hmacSHA1(key []byte) hash.Hash {
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return hmac.NewSHA1(key)
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}
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func rsaKA() keyAgreement {
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return rsaKeyAgreement{}
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}
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func ecdheRSAKA() keyAgreement {
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return new(ecdheRSAKeyAgreement)
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}
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// mutualCipherSuite returns a cipherSuite and its id given a list of supported
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// ciphersuites and the id requested by the peer.
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func mutualCipherSuite(have []uint16, want uint16) (suite *cipherSuite, id uint16) {
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for _, id := range have {
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if id == want {
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return cipherSuites[id], id
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}
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}
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return
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}
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// A list of the possible cipher suite ids. Taken from
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// http://www.iana.org/assignments/tls-parameters/tls-parameters.xml
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const (
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TLS_RSA_WITH_RC4_128_SHA uint16 = 0x0005
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TLS_RSA_WITH_AES_128_CBC_SHA uint16 = 0x002f
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TLS_ECDHE_RSA_WITH_RC4_128_SHA uint16 = 0xc011
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TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA uint16 = 0xc013
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)
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