diff options
Diffstat (limited to 'src/pkg/crypto/tls/common.go')
| -rw-r--r-- | src/pkg/crypto/tls/common.go | 153 |
1 files changed, 142 insertions, 11 deletions
diff --git a/src/pkg/crypto/tls/common.go b/src/pkg/crypto/tls/common.go index b7229d29f..fca98bdd1 100644 --- a/src/pkg/crypto/tls/common.go +++ b/src/pkg/crypto/tls/common.go @@ -5,9 +5,11 @@ package tls import ( + "container/list" "crypto" "crypto/rand" "crypto/x509" + "fmt" "io" "math/big" "strings" @@ -64,7 +66,7 @@ const ( ) // TLS extension numbers -var ( +const ( extensionServerName uint16 = 0 extensionStatusRequest uint16 = 5 extensionSupportedCurves uint16 = 10 @@ -72,19 +74,27 @@ var ( extensionSignatureAlgorithms uint16 = 13 extensionSessionTicket uint16 = 35 extensionNextProtoNeg uint16 = 13172 // not IANA assigned + extensionRenegotiationInfo uint16 = 0xff01 +) + +// TLS signaling cipher suite values +const ( + scsvRenegotiation uint16 = 0x00ff ) -// TLS Elliptic Curves +// CurveID is the type of a TLS identifier for an elliptic curve. See // http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-8 -var ( - curveP256 uint16 = 23 - curveP384 uint16 = 24 - curveP521 uint16 = 25 +type CurveID uint16 + +const ( + CurveP256 CurveID = 23 + CurveP384 CurveID = 24 + CurveP521 CurveID = 25 ) // TLS Elliptic Curve Point Formats // http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-9 -var ( +const ( pointFormatUncompressed uint8 = 0 ) @@ -145,6 +155,7 @@ var supportedClientCertSignatureAlgorithms = []signatureAndHash{ // ConnectionState records basic TLS details about the connection. type ConnectionState struct { + Version uint16 // TLS version used by the connection (e.g. VersionTLS12) HandshakeComplete bool // TLS handshake is complete DidResume bool // connection resumes a previous TLS connection CipherSuite uint16 // cipher suite in use (TLS_RSA_WITH_RC4_128_SHA, ...) @@ -167,12 +178,38 @@ const ( RequireAndVerifyClientCert ) -// A Config structure is used to configure a TLS client or server. After one -// has been passed to a TLS function it must not be modified. +// ClientSessionState contains the state needed by clients to resume TLS +// sessions. +type ClientSessionState struct { + sessionTicket []uint8 // Encrypted ticket used for session resumption with server + vers uint16 // SSL/TLS version negotiated for the session + cipherSuite uint16 // Ciphersuite negotiated for the session + masterSecret []byte // MasterSecret generated by client on a full handshake + serverCertificates []*x509.Certificate // Certificate chain presented by the server +} + +// ClientSessionCache is a cache of ClientSessionState objects that can be used +// by a client to resume a TLS session with a given server. ClientSessionCache +// implementations should expect to be called concurrently from different +// goroutines. +type ClientSessionCache interface { + // Get searches for a ClientSessionState associated with the given key. + // On return, ok is true if one was found. + Get(sessionKey string) (session *ClientSessionState, ok bool) + + // Put adds the ClientSessionState to the cache with the given key. + Put(sessionKey string, cs *ClientSessionState) +} + +// A Config structure is used to configure a TLS client or server. +// After one has been passed to a TLS function it must not be +// modified. A Config may be reused; the tls package will also not +// modify it. type Config struct { // Rand provides the source of entropy for nonces and RSA blinding. // If Rand is nil, TLS uses the cryptographic random reader in package // crypto/rand. + // The Reader must be safe for use by multiple goroutines. Rand io.Reader // Time returns the current time as the number of seconds since the epoch. @@ -200,8 +237,9 @@ type Config struct { // NextProtos is a list of supported, application level protocols. NextProtos []string - // ServerName is included in the client's handshake to support virtual - // hosting. + // ServerName is used to verify the hostname on the returned + // certificates unless InsecureSkipVerify is given. It is also included + // in the client's handshake to support virtual hosting. ServerName string // ClientAuth determines the server's policy for @@ -245,6 +283,10 @@ type Config struct { // connections using that key are compromised. SessionTicketKey [32]byte + // SessionCache is a cache of ClientSessionState entries for TLS session + // resumption. + ClientSessionCache ClientSessionCache + // MinVersion contains the minimum SSL/TLS version that is acceptable. // If zero, then SSLv3 is taken as the minimum. MinVersion uint16 @@ -254,6 +296,11 @@ type Config struct { // which is currently TLS 1.2. MaxVersion uint16 + // CurvePreferences contains the elliptic curves that will be used in + // an ECDHE handshake, in preference order. If empty, the default will + // be used. + CurvePreferences []CurveID + serverInitOnce sync.Once // guards calling (*Config).serverInit } @@ -312,6 +359,15 @@ func (c *Config) maxVersion() uint16 { return c.MaxVersion } +var defaultCurvePreferences = []CurveID{CurveP256, CurveP384, CurveP521} + +func (c *Config) curvePreferences() []CurveID { + if c == nil || len(c.CurvePreferences) == 0 { + return defaultCurvePreferences + } + return c.CurvePreferences +} + // mutualVersion returns the protocol version to use given the advertised // version of the peer. func (c *Config) mutualVersion(vers uint16) (uint16, bool) { @@ -406,6 +462,77 @@ type handshakeMessage interface { unmarshal([]byte) bool } +// lruSessionCache is a ClientSessionCache implementation that uses an LRU +// caching strategy. +type lruSessionCache struct { + sync.Mutex + + m map[string]*list.Element + q *list.List + capacity int +} + +type lruSessionCacheEntry struct { + sessionKey string + state *ClientSessionState +} + +// NewLRUClientSessionCache returns a ClientSessionCache with the given +// capacity that uses an LRU strategy. If capacity is < 1, a default capacity +// is used instead. +func NewLRUClientSessionCache(capacity int) ClientSessionCache { + const defaultSessionCacheCapacity = 64 + + if capacity < 1 { + capacity = defaultSessionCacheCapacity + } + return &lruSessionCache{ + m: make(map[string]*list.Element), + q: list.New(), + capacity: capacity, + } +} + +// Put adds the provided (sessionKey, cs) pair to the cache. +func (c *lruSessionCache) Put(sessionKey string, cs *ClientSessionState) { + c.Lock() + defer c.Unlock() + + if elem, ok := c.m[sessionKey]; ok { + entry := elem.Value.(*lruSessionCacheEntry) + entry.state = cs + c.q.MoveToFront(elem) + return + } + + if c.q.Len() < c.capacity { + entry := &lruSessionCacheEntry{sessionKey, cs} + c.m[sessionKey] = c.q.PushFront(entry) + return + } + + elem := c.q.Back() + entry := elem.Value.(*lruSessionCacheEntry) + delete(c.m, entry.sessionKey) + entry.sessionKey = sessionKey + entry.state = cs + c.q.MoveToFront(elem) + c.m[sessionKey] = elem +} + +// Get returns the ClientSessionState value associated with a given key. It +// returns (nil, false) if no value is found. +func (c *lruSessionCache) Get(sessionKey string) (*ClientSessionState, bool) { + c.Lock() + defer c.Unlock() + + if elem, ok := c.m[sessionKey]; ok { + c.q.MoveToFront(elem) + return elem.Value.(*lruSessionCacheEntry).state, true + } + return nil, false +} + // TODO(jsing): Make these available to both crypto/x509 and crypto/tls. type dsaSignature struct { R, S *big.Int @@ -435,3 +562,7 @@ func initDefaultCipherSuites() { varDefaultCipherSuites[i] = suite.id } } + +func unexpectedMessageError(wanted, got interface{}) error { + return fmt.Errorf("tls: received unexpected handshake message of type %T when waiting for %T", got, wanted) +} |