278 lines
8.0 KiB
Go
278 lines
8.0 KiB
Go
// 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 qtls
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/aes"
|
|
"crypto/cipher"
|
|
"crypto/hmac"
|
|
"crypto/sha256"
|
|
"crypto/subtle"
|
|
"encoding/binary"
|
|
"errors"
|
|
"io"
|
|
"time"
|
|
|
|
"golang.org/x/crypto/cryptobyte"
|
|
)
|
|
|
|
// 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
|
|
createdAt uint64
|
|
masterSecret []byte // opaque master_secret<1..2^16-1>;
|
|
// struct { opaque certificate<1..2^24-1> } Certificate;
|
|
certificates [][]byte // Certificate certificate_list<0..2^24-1>;
|
|
|
|
// usedOldKey is true if the ticket from which this session came from
|
|
// was encrypted with an older key and thus should be refreshed.
|
|
usedOldKey bool
|
|
}
|
|
|
|
func (m *sessionState) marshal() ([]byte, error) {
|
|
var b cryptobyte.Builder
|
|
b.AddUint16(m.vers)
|
|
b.AddUint16(m.cipherSuite)
|
|
addUint64(&b, m.createdAt)
|
|
b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
b.AddBytes(m.masterSecret)
|
|
})
|
|
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
for _, cert := range m.certificates {
|
|
b.AddUint24LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
b.AddBytes(cert)
|
|
})
|
|
}
|
|
})
|
|
return b.Bytes()
|
|
}
|
|
|
|
func (m *sessionState) unmarshal(data []byte) bool {
|
|
*m = sessionState{usedOldKey: m.usedOldKey}
|
|
s := cryptobyte.String(data)
|
|
if ok := s.ReadUint16(&m.vers) &&
|
|
s.ReadUint16(&m.cipherSuite) &&
|
|
readUint64(&s, &m.createdAt) &&
|
|
readUint16LengthPrefixed(&s, &m.masterSecret) &&
|
|
len(m.masterSecret) != 0; !ok {
|
|
return false
|
|
}
|
|
var certList cryptobyte.String
|
|
if !s.ReadUint24LengthPrefixed(&certList) {
|
|
return false
|
|
}
|
|
for !certList.Empty() {
|
|
var cert []byte
|
|
if !readUint24LengthPrefixed(&certList, &cert) {
|
|
return false
|
|
}
|
|
m.certificates = append(m.certificates, cert)
|
|
}
|
|
return s.Empty()
|
|
}
|
|
|
|
// sessionStateTLS13 is the content of a TLS 1.3 session ticket. Its first
|
|
// version (revision = 0) doesn't carry any of the information needed for 0-RTT
|
|
// validation and the nonce is always empty.
|
|
// version (revision = 1) carries the max_early_data_size sent in the ticket.
|
|
// version (revision = 2) carries the ALPN sent in the ticket.
|
|
type sessionStateTLS13 struct {
|
|
// uint8 version = 0x0304;
|
|
// uint8 revision = 2;
|
|
cipherSuite uint16
|
|
createdAt uint64
|
|
resumptionSecret []byte // opaque resumption_master_secret<1..2^8-1>;
|
|
certificate Certificate // CertificateEntry certificate_list<0..2^24-1>;
|
|
maxEarlyData uint32
|
|
alpn string
|
|
|
|
appData []byte
|
|
}
|
|
|
|
func (m *sessionStateTLS13) marshal() ([]byte, error) {
|
|
var b cryptobyte.Builder
|
|
b.AddUint16(VersionTLS13)
|
|
b.AddUint8(2) // revision
|
|
b.AddUint16(m.cipherSuite)
|
|
addUint64(&b, m.createdAt)
|
|
b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
b.AddBytes(m.resumptionSecret)
|
|
})
|
|
marshalCertificate(&b, m.certificate)
|
|
b.AddUint32(m.maxEarlyData)
|
|
b.AddUint8LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
b.AddBytes([]byte(m.alpn))
|
|
})
|
|
b.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
|
|
b.AddBytes(m.appData)
|
|
})
|
|
return b.Bytes()
|
|
}
|
|
|
|
func (m *sessionStateTLS13) unmarshal(data []byte) bool {
|
|
*m = sessionStateTLS13{}
|
|
s := cryptobyte.String(data)
|
|
var version uint16
|
|
var revision uint8
|
|
var alpn []byte
|
|
ret := s.ReadUint16(&version) &&
|
|
version == VersionTLS13 &&
|
|
s.ReadUint8(&revision) &&
|
|
revision == 2 &&
|
|
s.ReadUint16(&m.cipherSuite) &&
|
|
readUint64(&s, &m.createdAt) &&
|
|
readUint8LengthPrefixed(&s, &m.resumptionSecret) &&
|
|
len(m.resumptionSecret) != 0 &&
|
|
unmarshalCertificate(&s, &m.certificate) &&
|
|
s.ReadUint32(&m.maxEarlyData) &&
|
|
readUint8LengthPrefixed(&s, &alpn) &&
|
|
readUint16LengthPrefixed(&s, &m.appData) &&
|
|
s.Empty()
|
|
m.alpn = string(alpn)
|
|
return ret
|
|
}
|
|
|
|
func (c *Conn) encryptTicket(state []byte) ([]byte, error) {
|
|
if len(c.ticketKeys) == 0 {
|
|
return nil, errors.New("tls: internal error: session ticket keys unavailable")
|
|
}
|
|
|
|
encrypted := make([]byte, ticketKeyNameLen+aes.BlockSize+len(state)+sha256.Size)
|
|
keyName := encrypted[:ticketKeyNameLen]
|
|
iv := encrypted[ticketKeyNameLen : ticketKeyNameLen+aes.BlockSize]
|
|
macBytes := encrypted[len(encrypted)-sha256.Size:]
|
|
|
|
if _, err := io.ReadFull(c.config.rand(), iv); err != nil {
|
|
return nil, err
|
|
}
|
|
key := c.ticketKeys[0]
|
|
copy(keyName, key.keyName[:])
|
|
block, err := aes.NewCipher(key.aesKey[:])
|
|
if err != nil {
|
|
return nil, errors.New("tls: failed to create cipher while encrypting ticket: " + err.Error())
|
|
}
|
|
cipher.NewCTR(block, iv).XORKeyStream(encrypted[ticketKeyNameLen+aes.BlockSize:], state)
|
|
|
|
mac := hmac.New(sha256.New, key.hmacKey[:])
|
|
mac.Write(encrypted[:len(encrypted)-sha256.Size])
|
|
mac.Sum(macBytes[:0])
|
|
|
|
return encrypted, nil
|
|
}
|
|
|
|
func (c *Conn) decryptTicket(encrypted []byte) (plaintext []byte, usedOldKey bool) {
|
|
if len(encrypted) < ticketKeyNameLen+aes.BlockSize+sha256.Size {
|
|
return nil, false
|
|
}
|
|
|
|
keyName := encrypted[:ticketKeyNameLen]
|
|
iv := encrypted[ticketKeyNameLen : ticketKeyNameLen+aes.BlockSize]
|
|
macBytes := encrypted[len(encrypted)-sha256.Size:]
|
|
ciphertext := encrypted[ticketKeyNameLen+aes.BlockSize : len(encrypted)-sha256.Size]
|
|
|
|
keyIndex := -1
|
|
for i, candidateKey := range c.ticketKeys {
|
|
if bytes.Equal(keyName, candidateKey.keyName[:]) {
|
|
keyIndex = i
|
|
break
|
|
}
|
|
}
|
|
if keyIndex == -1 {
|
|
return nil, false
|
|
}
|
|
key := &c.ticketKeys[keyIndex]
|
|
|
|
mac := hmac.New(sha256.New, key.hmacKey[:])
|
|
mac.Write(encrypted[:len(encrypted)-sha256.Size])
|
|
expected := mac.Sum(nil)
|
|
|
|
if subtle.ConstantTimeCompare(macBytes, expected) != 1 {
|
|
return nil, false
|
|
}
|
|
|
|
block, err := aes.NewCipher(key.aesKey[:])
|
|
if err != nil {
|
|
return nil, false
|
|
}
|
|
plaintext = make([]byte, len(ciphertext))
|
|
cipher.NewCTR(block, iv).XORKeyStream(plaintext, ciphertext)
|
|
|
|
return plaintext, keyIndex > 0
|
|
}
|
|
|
|
func (c *Conn) getSessionTicketMsg(appData []byte) (*newSessionTicketMsgTLS13, error) {
|
|
m := new(newSessionTicketMsgTLS13)
|
|
|
|
var certsFromClient [][]byte
|
|
for _, cert := range c.peerCertificates {
|
|
certsFromClient = append(certsFromClient, cert.Raw)
|
|
}
|
|
state := sessionStateTLS13{
|
|
cipherSuite: c.cipherSuite,
|
|
createdAt: uint64(c.config.time().Unix()),
|
|
resumptionSecret: c.resumptionSecret,
|
|
certificate: Certificate{
|
|
Certificate: certsFromClient,
|
|
OCSPStaple: c.ocspResponse,
|
|
SignedCertificateTimestamps: c.scts,
|
|
},
|
|
appData: appData,
|
|
alpn: c.clientProtocol,
|
|
}
|
|
if c.extraConfig != nil {
|
|
state.maxEarlyData = c.extraConfig.MaxEarlyData
|
|
}
|
|
stateBytes, err := state.marshal()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
m.label, err = c.encryptTicket(stateBytes)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
m.lifetime = uint32(maxSessionTicketLifetime / time.Second)
|
|
|
|
// ticket_age_add is a random 32-bit value. See RFC 8446, section 4.6.1
|
|
// The value is not stored anywhere; we never need to check the ticket age
|
|
// because 0-RTT is not supported.
|
|
ageAdd := make([]byte, 4)
|
|
_, err = c.config.rand().Read(ageAdd)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
m.ageAdd = binary.LittleEndian.Uint32(ageAdd)
|
|
|
|
// ticket_nonce, which must be unique per connection, is always left at
|
|
// zero because we only ever send one ticket per connection.
|
|
|
|
if c.extraConfig != nil {
|
|
m.maxEarlyData = c.extraConfig.MaxEarlyData
|
|
}
|
|
return m, nil
|
|
}
|
|
|
|
// GetSessionTicket generates a new session ticket.
|
|
// It should only be called after the handshake completes.
|
|
// It can only be used for servers, and only if the alternative record layer is set.
|
|
// The ticket may be nil if config.SessionTicketsDisabled is set,
|
|
// or if the client isn't able to receive session tickets.
|
|
func (c *Conn) GetSessionTicket(appData []byte) ([]byte, error) {
|
|
if c.isClient || !c.handshakeComplete() || c.extraConfig == nil || c.extraConfig.AlternativeRecordLayer == nil {
|
|
return nil, errors.New("GetSessionTicket is only valid for servers after completion of the handshake, and if an alternative record layer is set.")
|
|
}
|
|
if c.config.SessionTicketsDisabled {
|
|
return nil, nil
|
|
}
|
|
|
|
m, err := c.getSessionTicketMsg(appData)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return m.marshal()
|
|
}
|