1 files changed, 182 insertions, 0 deletions
diff --git a/src/pkg/crypto/tls/ticket.go b/src/pkg/crypto/tls/ticket.go
new file mode 100644
index 000000000..4cfc5a53f
--- /dev/null
+++ b/src/pkg/crypto/tls/ticket.go
@@ -0,0 +1,182 @@
+// Copyright 2012 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/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/sha256"
+	"crypto/subtle"
+	"errors"
+	"io"
+)
+
+// sessionState contains the information that is serialized into a session
+// ticket in order to later resume a connection.
+type sessionState struct {
+	vers         uint16
+	cipherSuite  uint16
+	masterSecret []byte
+	certificates [][]byte
+}
+
+func (s *sessionState) equal(i interface{}) bool {
+	s1, ok := i.(*sessionState)
+	if !ok {
+		return false
+	}
+
+	if s.vers != s1.vers ||
+		s.cipherSuite != s1.cipherSuite ||
+		!bytes.Equal(s.masterSecret, s1.masterSecret) {
+		return false
+	}
+
+	if len(s.certificates) != len(s1.certificates) {
+		return false
+	}
+
+	for i := range s.certificates {
+		if !bytes.Equal(s.certificates[i], s1.certificates[i]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (s *sessionState) marshal() []byte {
+	length := 2 + 2 + 2 + len(s.masterSecret) + 2
+	for _, cert := range s.certificates {
+		length += 4 + len(cert)
+	}
+
+	ret := make([]byte, length)
+	x := ret
+	x[0] = byte(s.vers >> 8)
+	x[1] = byte(s.vers)
+	x[2] = byte(s.cipherSuite >> 8)
+	x[3] = byte(s.cipherSuite)
+	x[4] = byte(len(s.masterSecret) >> 8)
+	x[5] = byte(len(s.masterSecret))
+	x = x[6:]
+	copy(x, s.masterSecret)
+	x = x[len(s.masterSecret):]
+
+	x[0] = byte(len(s.certificates) >> 8)
+	x[1] = byte(len(s.certificates))
+	x = x[2:]
+
+	for _, cert := range s.certificates {
+		x[0] = byte(len(cert) >> 24)
+		x[1] = byte(len(cert) >> 16)
+		x[2] = byte(len(cert) >> 8)
+		x[3] = byte(len(cert))
+		copy(x[4:], cert)
+		x = x[4+len(cert):]
+	}
+
+	return ret
+}
+
+func (s *sessionState) unmarshal(data []byte) bool {
+	if len(data) < 8 {
+		return false
+	}
+
+	s.vers = uint16(data[0])<<8 | uint16(data[1])
+	s.cipherSuite = uint16(data[2])<<8 | uint16(data[3])
+	masterSecretLen := int(data[4])<<8 | int(data[5])
+	data = data[6:]
+	if len(data) < masterSecretLen {
+		return false
+	}
+
+	s.masterSecret = data[:masterSecretLen]
+	data = data[masterSecretLen:]
+
+	if len(data) < 2 {
+		return false
+	}
+
+	numCerts := int(data[0])<<8 | int(data[1])
+	data = data[2:]
+
+	s.certificates = make([][]byte, numCerts)
+	for i := range s.certificates {
+		if len(data) < 4 {
+			return false
+		}
+		certLen := int(data[0])<<24 | int(data[1])<<16 | int(data[2])<<8 | int(data[3])
+		data = data[4:]
+		if certLen < 0 {
+			return false
+		}
+		if len(data) < certLen {
+			return false
+		}
+		s.certificates[i] = data[:certLen]
+		data = data[certLen:]
+	}
+
+	if len(data) > 0 {
+		return false
+	}
+
+	return true
+}
+
+func (c *Conn) encryptTicket(state *sessionState) ([]byte, error) {
+	serialized := state.marshal()
+	encrypted := make([]byte, aes.BlockSize+len(serialized)+sha256.Size)
+	iv := encrypted[:aes.BlockSize]
+	macBytes := encrypted[len(encrypted)-sha256.Size:]
+
+	if _, err := io.ReadFull(c.config.rand(), iv); err != nil {
+		return nil, err
+	}
+	block, err := aes.NewCipher(c.config.SessionTicketKey[:16])
+	if err != nil {
+		return nil, errors.New("tls: failed to create cipher while encrypting ticket: " + err.Error())
+	}
+	cipher.NewCTR(block, iv).XORKeyStream(encrypted[aes.BlockSize:], serialized)
+
+	mac := hmac.New(sha256.New, c.config.SessionTicketKey[16:32])
+	mac.Write(encrypted[:len(encrypted)-sha256.Size])
+	mac.Sum(macBytes[:0])
+
+	return encrypted, nil
+}
+
+func (c *Conn) decryptTicket(encrypted []byte) (*sessionState, bool) {
+	if len(encrypted) < aes.BlockSize+sha256.Size {
+		return nil, false
+	}
+
+	iv := encrypted[:aes.BlockSize]
+	macBytes := encrypted[len(encrypted)-sha256.Size:]
+
+	mac := hmac.New(sha256.New, c.config.SessionTicketKey[16:32])
+	mac.Write(encrypted[:len(encrypted)-sha256.Size])
+	expected := mac.Sum(nil)
+
+	if subtle.ConstantTimeCompare(macBytes, expected) != 1 {
+		return nil, false
+	}
+
+	block, err := aes.NewCipher(c.config.SessionTicketKey[:16])
+	if err != nil {
+		return nil, false
+	}
+	ciphertext := encrypted[aes.BlockSize : len(encrypted)-sha256.Size]
+	plaintext := ciphertext
+	cipher.NewCTR(block, iv).XORKeyStream(plaintext, ciphertext)
+
+	state := new(sessionState)
+	ok := state.unmarshal(plaintext)
+	return state, ok
+}