// Copyright 2010 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.
// TLS low level connection and record layer
package runner
import (
"bytes"
"crypto/cipher"
"crypto/ecdsa"
"crypto/subtle"
"crypto/x509"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"sync"
"time"
)
var errNoCertificateAlert = errors.New("tls: no certificate alert")
var errEndOfEarlyDataAlert = errors.New("tls: end of early data alert")
// A Conn represents a secured connection.
// It implements the net.Conn interface.
type Conn struct {
// constant
conn net.Conn
isDTLS bool
isClient bool
// constant after handshake; protected by handshakeMutex
handshakeMutex sync.Mutex // handshakeMutex < in.Mutex, out.Mutex, errMutex
handshakeErr error // error resulting from handshake
wireVersion uint16 // TLS wire version
vers uint16 // TLS version
haveVers bool // version has been negotiated
config *Config // configuration passed to constructor
handshakeComplete bool
skipEarlyData bool // On a server, indicates that the client is sending early data that must be skipped over.
didResume bool // whether this connection was a session resumption
extendedMasterSecret bool // whether this session used an extended master secret
cipherSuite *cipherSuite
earlyCipherSuite *cipherSuite
ocspResponse []byte // stapled OCSP response
sctList []byte // signed certificate timestamp list
peerCertificates []*x509.Certificate
// verifiedChains contains the certificate chains that we built, as
// opposed to the ones presented by the server.
verifiedChains [][]*x509.Certificate
// serverName contains the server name indicated by the client, if any.
serverName string
// firstFinished contains the first Finished hash sent during the
// handshake. This is the "tls-unique" channel binding value.
firstFinished [12]byte
// peerSignatureAlgorithm contains the signature algorithm that was used
// by the peer in the handshake, or zero if not applicable.
peerSignatureAlgorithm signatureAlgorithm
// curveID contains the curve that was used in the handshake, or zero if
// not applicable.
curveID CurveID
// quicTransportParams contains the QUIC transport params received
// by the peer.
quicTransportParams []byte
clientRandom, serverRandom [32]byte
earlyExporterSecret []byte
exporterSecret []byte
resumptionSecret []byte
clientProtocol string
clientProtocolFallback bool
usedALPN bool
// verify_data values for the renegotiation extension.
clientVerify []byte
serverVerify []byte
channelID *ecdsa.PublicKey
tokenBindingNegotiated bool
tokenBindingParam uint8
srtpProtectionProfile uint16
clientVersion uint16
// input/output
in, out halfConn // in.Mutex < out.Mutex
rawInput *block // raw input, right off the wire
input *block // application record waiting to be read
hand bytes.Buffer // handshake record waiting to be read
// pendingFlight, if PackHandshakeFlight is enabled, is the buffer of
// handshake data to be split into records at the end of the flight.
pendingFlight bytes.Buffer
// DTLS state
sendHandshakeSeq uint16
recvHandshakeSeq uint16
handMsg []byte // pending assembled handshake message
handMsgLen int // handshake message length, not including the header
pendingFragments [][]byte // pending outgoing handshake fragments.
pendingPacket []byte // pending outgoing packet.
keyUpdateSeen bool
keyUpdateRequested bool
seenOneByteRecord bool
expectTLS13ChangeCipherSpec bool
// seenHandshakePackEnd is whether the most recent handshake record was
// not full for ExpectPackedEncryptedHandshake. If true, no more
// handshake data may be received until the next flight or epoch change.
seenHandshakePackEnd bool
tmp [16]byte
}
func (c *Conn) init() {
c.in.isDTLS = c.isDTLS
c.out.isDTLS = c.isDTLS
c.in.config = c.config
c.out.config = c.config
c.out.updateOutSeq()
}
// Access to net.Conn methods.
// Cannot just embed net.Conn because that would
// export the struct field too.
// LocalAddr returns the local network address.
func (c *Conn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
// RemoteAddr returns the remote network address.
func (c *Conn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
// SetDeadline sets the read and write deadlines associated with the connection.
// A zero value for t means Read and Write will not time out.
// After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.
func (c *Conn) SetDeadline(t time.Time) error {
return c.conn.SetDeadline(t)
}
// SetReadDeadline sets the read deadline on the underlying connection.
// A zero value for t means Read will not time out.
func (c *Conn) SetReadDeadline(t time.Time) error {
return c.conn.SetReadDeadline(t)
}
// SetWriteDeadline sets the write deadline on the underlying conneciton.
// A zero value for t means Write will not time out.
// After a Write has timed out, the TLS state is corrupt and all future writes will return the same error.
func (c *Conn) SetWriteDeadline(t time.Time) error {
return c.conn.SetWriteDeadline(t)
}
// A halfConn represents one direction of the record layer
// connection, either sending or receiving.
type halfConn struct {
sync.Mutex
err error // first permanent error
version uint16 // protocol version
wireVersion uint16 // wire version
isDTLS bool
cipher interface{} // cipher algorithm
mac macFunction
seq [8]byte // 64-bit sequence number
outSeq [8]byte // Mapped sequence number
bfree *block // list of free blocks
nextCipher interface{} // next encryption state
nextMac macFunction // next MAC algorithm
nextSeq [6]byte // next epoch's starting sequence number in DTLS
// used to save allocating a new buffer for each MAC.
inDigestBuf, outDigestBuf []byte
trafficSecret []byte
config *Config
}
func (hc *halfConn) setErrorLocked(err error) error {
hc.err = err
return err
}
func (hc *halfConn) error() error {
// This should be locked, but I've removed it for the renegotiation
// tests since we don't concurrently read and write the same tls.Conn
// in any case during testing.
err := hc.err
return err
}
// prepareCipherSpec sets the encryption and MAC states
// that a subsequent changeCipherSpec will use.
func (hc *halfConn) prepareCipherSpec(version uint16, cipher interface{}, mac macFunction) {
hc.wireVersion = version
protocolVersion, ok := wireToVersion(version, hc.isDTLS)
if !ok {
panic("TLS: unknown version")
}
hc.version = protocolVersion
hc.nextCipher = cipher
hc.nextMac = mac
}
// changeCipherSpec changes the encryption and MAC states
// to the ones previously passed to prepareCipherSpec.
func (hc *halfConn) changeCipherSpec(config *Config) error {
if hc.nextCipher == nil {
return alertInternalError
}
hc.cipher = hc.nextCipher
hc.mac = hc.nextMac
hc.nextCipher = nil
hc.nextMac = nil
hc.config = config
hc.incEpoch()
if config.Bugs.NullAllCiphers {
hc.cipher = nullCipher{}
hc.mac = nil
}
return nil
}
// useTrafficSecret sets the current cipher state for TLS 1.3.
func (hc *halfConn) useTrafficSecret(version uint16, suite *cipherSuite, secret []byte, side trafficDirection) {
hc.wireVersion = version
protocolVersion, ok := wireToVersion(version, hc.isDTLS)
if !ok {
panic("TLS: unknown version")
}
hc.version = protocolVersion
hc.cipher = deriveTrafficAEAD(version, suite, secret, side)
if hc.config.Bugs.NullAllCiphers {
hc.cipher = nullCipher{}
}
hc.trafficSecret = secret
hc.incEpoch()
}
// resetCipher changes the cipher state back to no encryption to be able
// to send an unencrypted ClientHello in response to HelloRetryRequest
// after 0-RTT data was rejected.
func (hc *halfConn) resetCipher() {
hc.cipher = nil
hc.incEpoch()
}
// incSeq increments the sequence number.
func (hc *halfConn) incSeq(isOutgoing bool) {
limit := 0
increment := uint64(1)
if hc.isDTLS {
// Increment up to the epoch in DTLS.
limit = 2
}
for i := 7; i >= limit; i-- {
increment += uint64(hc.seq[i])
hc.seq[i] = byte(increment)
increment >>= 8
}
// Not allowed to let sequence number wrap.
// Instead, must renegotiate before it does.
// Not likely enough to bother.
if increment != 0 {
panic("TLS: sequence number wraparound")
}
hc.updateOutSeq()
}
// incNextSeq increments the starting sequence number for the next epoch.
func (hc *halfConn) incNextSeq() {
for i := len(hc.nextSeq) - 1; i >= 0; i-- {
hc.nextSeq[i]++
if hc.nextSeq[i] != 0 {
return
}
}
panic("TLS: sequence number wraparound")
}
// incEpoch resets the sequence number. In DTLS, it also increments the epoch
// half of the sequence number.
func (hc *halfConn) incEpoch() {
if hc.isDTLS {
for i := 1; i >= 0; i-- {
hc.seq[i]++
if hc.seq[i] != 0 {
break
}
if i == 0 {
panic("TLS: epoch number wraparound")
}
}
copy(hc.seq[2:], hc.nextSeq[:])
for i := range hc.nextSeq {
hc.nextSeq[i] = 0
}
} else {
for i := range hc.seq {
hc.seq[i] = 0
}
}
hc.updateOutSeq()
}
func (hc *halfConn) updateOutSeq() {
if hc.config.Bugs.SequenceNumberMapping != nil {
seqU64 := binary.BigEndian.Uint64(hc.seq[:])
seqU64 = hc.config.Bugs.SequenceNumberMapping(seqU64)
binary.BigEndian.PutUint64(hc.outSeq[:], seqU64)
// The DTLS epoch cannot be changed.
copy(hc.outSeq[:2], hc.seq[:2])
return
}
copy(hc.outSeq[:], hc.seq[:])
}
func (hc *halfConn) recordHeaderLen() int {
if hc.isDTLS {
return dtlsRecordHeaderLen
}
return tlsRecordHeaderLen
}
// removePadding returns an unpadded slice, in constant time, which is a prefix
// of the input. It also returns a byte which is equal to 255 if the padding
// was valid and 0 otherwise. See RFC 2246, section 6.2.3.2
func removePadding(payload []byte) ([]byte, byte) {
if len(payload) < 1 {
return payload, 0
}
paddingLen := payload[len(payload)-1]
t := uint(len(payload)-1) - uint(paddingLen)
// if len(payload) >= (paddingLen - 1) then the MSB of t is zero
good := byte(int32(^t) >> 31)
toCheck := 255 // the maximum possible padding length
// The length of the padded data is public, so we can use an if here
if toCheck+1 > len(payload) {
toCheck = len(payload) - 1
}
for i := 0; i < toCheck; i++ {
t := uint(paddingLen) - uint(i)
// if i <= paddingLen then the MSB of t is zero
mask := byte(int32(^t) >> 31)
b := payload[len(payload)-1-i]
good &^= mask&paddingLen ^ mask&b
}
// We AND together the bits of good and replicate the result across
// all the bits.
good &= good << 4
good &= good << 2
good &= good << 1
good = uint8(int8(good) >> 7)
toRemove := good&paddingLen + 1
return payload[:len(payload)-int(toRemove)], good
}
// removePaddingSSL30 is a replacement for removePadding in the case that the
// protocol version is SSLv3. In this version, the contents of the padding
// are random and cannot be checked.
func removePaddingSSL30(payload []byte) ([]byte, byte) {
if len(payload) < 1 {
return payload, 0
}
paddingLen := int(payload[len(payload)-1]) + 1
if paddingLen > len(payload) {
return payload, 0
}
return payload[:len(payload)-paddingLen], 255
}
func roundUp(a, b int) int {
return a + (b-a%b)%b
}
// cbcMode is an interface for block ciphers using cipher block chaining.
type cbcMode interface {
cipher.BlockMode
SetIV([]byte)
}
// decrypt checks and strips the mac and decrypts the data in b. Returns a
// success boolean, the number of bytes to skip from the start of the record in
// order to get the application payload, the encrypted record type (or 0
// if there is none), and an optional alert value.
func (hc *halfConn) decrypt(b *block) (ok bool, prefixLen int, contentType recordType, alertValue alert) {
recordHeaderLen := hc.recordHeaderLen()
// pull out payload
payload := b.data[recordHeaderLen:]
macSize := 0
if hc.mac != nil {
macSize = hc.mac.Size()
}
paddingGood := byte(255)
explicitIVLen := 0
seq := hc.seq[:]
if hc.isDTLS {
// DTLS sequence numbers are explicit.
seq = b.data[3:11]
}
// decrypt
if hc.cipher != nil {
switch c := hc.cipher.(type) {
case cipher.Stream:
c.XORKeyStream(payload, payload)
case *tlsAead:
nonce := seq
if c.explicitNonce {
explicitIVLen = 8
if len(payload) < explicitIVLen {
return false, 0, 0, alertBadRecordMAC
}
nonce = payload[:8]
payload = payload[8:]
}
var additionalData []byte
if hc.version < VersionTLS13 {
additionalData = make([]byte, 13)
copy(additionalData, seq)
copy(additionalData[8:], b.data[:3])
n := len(payload) - c.Overhead()
additionalData[11] = byte(n >> 8)
additionalData[12] = byte(n)
} else {
additionalData = b.data[:recordHeaderLen]
}
var err error
payload, err = c.Open(payload[:0], nonce, payload, additionalData)
if err != nil {
return false, 0, 0, alertBadRecordMAC
}
b.resize(recordHeaderLen + explicitIVLen + len(payload))
case cbcMode:
blockSize := c.BlockSize()
if hc.version >= VersionTLS11 || hc.isDTLS {
explicitIVLen = blockSize
}
if len(payload)%blockSize != 0 || len(payload) < roundUp(explicitIVLen+macSize+1, blockSize) {
return false, 0, 0, alertBadRecordMAC
}
if explicitIVLen > 0 {
c.SetIV(payload[:explicitIVLen])
payload = payload[explicitIVLen:]
}
c.CryptBlocks(payload, payload)
if hc.version == VersionSSL30 {
payload, paddingGood = removePaddingSSL30(payload)
} else {
payload, paddingGood = removePadding(payload)
}
b.resize(recordHeaderLen + explicitIVLen + len(payload))
// note that we still have a timing side-channel in the
// MAC check, below. An attacker can align the record
// so that a correct padding will cause one less hash
// block to be calculated. Then they can iteratively
// decrypt a record by breaking each byte. See
// "Password Interception in a SSL/TLS Channel", Brice
// Canvel et al.
//
// However, our behavior matches OpenSSL, so we leak
// only as much as they do.
case nullCipher:
break
default:
panic("unknown cipher type")
}
if hc.version >= VersionTLS13 {
i := len(payload)
for i > 0 && payload[i-1] == 0 {
i--
}
payload = payload[:i]
if len(payload) == 0 {
return false, 0, 0, alertUnexpectedMessage
}
contentType = recordType(payload[len(payload)-1])
payload = payload[:len(payload)-1]
b.resize(recordHeaderLen + len(payload))
}
}
// check, strip mac
if hc.mac != nil {
if len(payload) < macSize {
return false, 0, 0, alertBadRecordMAC
}
// strip mac off payload, b.data
n := len(payload) - macSize
b.data[recordHeaderLen-2] = byte(n >> 8)
b.data[recordHeaderLen-1] = byte(n)
b.resize(recordHeaderLen + explicitIVLen + n)
remoteMAC := payload[n:]
localMAC := hc.mac.MAC(hc.inDigestBuf, seq, b.data[:3], b.data[recordHeaderLen-2:recordHeaderLen], payload[:n])
if subtle.ConstantTimeCompare(localMAC, remoteMAC) != 1 || paddingGood != 255 {
return false, 0, 0, alertBadRecordMAC
}
hc.inDigestBuf = localMAC
}
hc.incSeq(false)
return true, recordHeaderLen + explicitIVLen, contentType, 0
}
// padToBlockSize calculates the needed padding block, if any, for a payload.
// On exit, prefix aliases payload and extends to the end of the last full
// block of payload. finalBlock is a fresh slice which contains the contents of
// any suffix of payload as well as the needed padding to make finalBlock a
// full block.
func padToBlockSize(payload []byte, blockSize int, config *Config) (prefix, finalBlock []byte) {
overrun := len(payload) % blockSize
prefix = payload[:len(payload)-overrun]
paddingLen := blockSize - overrun
finalSize := blockSize
if config.Bugs.MaxPadding {
for paddingLen+blockSize <= 256 {
paddingLen += blockSize
}
finalSize = 256
}
finalBlock = make([]byte, finalSize)
for i := range finalBlock {
finalBlock[i] = byte(paddingLen - 1)
}
if config.Bugs.PaddingFirstByteBad || config.Bugs.PaddingFirstByteBadIf255 && paddingLen == 256 {
finalBlock[overrun] ^= 0xff
}
copy(finalBlock, payload[len(payload)-overrun:])
return
}
// encrypt encrypts and macs the data in b.
func (hc *halfConn) encrypt(b *block, explicitIVLen int, typ recordType) (bool, alert) {
recordHeaderLen := hc.recordHeaderLen()
// mac
if hc.mac != nil {
mac := hc.mac.MAC(hc.outDigestBuf, hc.outSeq[0:], b.data[:3], b.data[recordHeaderLen-2:recordHeaderLen], b.data[recordHeaderLen+explicitIVLen:])
n := len(b.data)
b.resize(n + len(mac))
copy(b.data[n:], mac)
hc.outDigestBuf = mac
}
payload := b.data[recordHeaderLen:]
// encrypt
if hc.cipher != nil {
// Add TLS 1.3 padding.
if hc.version >= VersionTLS13 {
paddingLen := hc.config.Bugs.RecordPadding
if hc.config.Bugs.OmitRecordContents {
b.resize(recordHeaderLen + paddingLen)
} else {
b.resize(len(b.data) + 1 + paddingLen)
b.data[len(b.data)-paddingLen-1] = byte(typ)
}
for i := 0; i < paddingLen; i++ {
b.data[len(b.data)-paddingLen+i] = 0
}
}
switch c := hc.cipher.(type) {
case cipher.Stream:
c.XORKeyStream(payload, payload)
case *tlsAead:
payloadLen := len(b.data) - recordHeaderLen - explicitIVLen
b.resize(len(b.data) + c.Overhead())
nonce := hc.outSeq[:]
if c.explicitNonce {
nonce = b.data[recordHeaderLen : recordHeaderLen+explicitIVLen]
}
payload := b.data[recordHeaderLen+explicitIVLen:]
payload = payload[:payloadLen]
var additionalData []byte
if hc.version < VersionTLS13 {
additionalData = make([]byte, 13)
copy(additionalData, hc.outSeq[:])
copy(additionalData[8:], b.data[:3])
additionalData[11] = byte(payloadLen >> 8)
additionalData[12] = byte(payloadLen)
} else {
additionalData = make([]byte, 5)
copy(additionalData, b.data[:3])
n := len(b.data) - recordHeaderLen
additionalData[3] = byte(n >> 8)
additionalData[4] = byte(n)
}
c.Seal(payload[:0], nonce, payload, additionalData)
case cbcMode:
blockSize := c.BlockSize()
if explicitIVLen > 0 {
c.SetIV(payload[:explicitIVLen])
payload = payload[explicitIVLen:]
}
prefix, finalBlock := padToBlockSize(payload, blockSize, hc.config)
b.resize(recordHeaderLen + explicitIVLen + len(prefix) + len(finalBlock))
c.CryptBlocks(b.data[recordHeaderLen+explicitIVLen:], prefix)
c.CryptBlocks(b.data[recordHeaderLen+explicitIVLen+len(prefix):], finalBlock)
case nullCipher:
break
default:
panic("unknown cipher type")
}
}
// update length to include MAC and any block padding needed.
n := len(b.data) - recordHeaderLen
b.data[recordHeaderLen-2] = byte(n >> 8)
b.data[recordHeaderLen-1] = byte(n)
hc.incSeq(true)
return true, 0
}
// A block is a simple data buffer.
type block struct {
data []byte
off int // index for Read
link *block
}
// resize resizes block to be n bytes, growing if necessary.
func (b *block) resize(n int) {
if n > cap(b.data) {
b.reserve(n)
}
b.data = b.data[0:n]
}
// reserve makes sure that block contains a capacity of at least n bytes.
func (b *block) reserve(n int) {
if cap(b.data) >= n {
return
}
m := cap(b.data)
if m == 0 {
m = 1024
}
for m < n {
m *= 2
}
data := make([]byte, len(b.data), m)
copy(data, b.data)
b.data = data
}
// readFromUntil reads from r into b until b contains at least n bytes
// or else returns an error.
func (b *block) readFromUntil(r io.Reader, n int) error {
// quick case
if len(b.data) >= n {
return nil
}
// read until have enough.
b.reserve(n)
for {
m, err := r.Read(b.data[len(b.data):cap(b.data)])
b.data = b.data[0 : len(b.data)+m]
if len(b.data) >= n {
// TODO(bradfitz,agl): slightly suspicious
// that we're throwing away r.Read's err here.
break
}
if err != nil {
return err
}
}
return nil
}
func (b *block) Read(p []byte) (n int, err error) {
n = copy(p, b.data[b.off:])
b.off += n
return
}
// newBlock allocates a new block, from hc's free list if possible.
func (hc *halfConn) newBlock() *block {
b := hc.bfree
if b == nil {
return new(block)
}
hc.bfree = b.link
b.link = nil
b.resize(0)
return b
}
// freeBlock returns a block to hc's free list.
// The protocol is such that each side only has a block or two on
// its free list at a time, so there's no need to worry about
// trimming the list, etc.
func (hc *halfConn) freeBlock(b *block) {
b.link = hc.bfree
hc.bfree = b
}
// splitBlock splits a block after the first n bytes,
// returning a block with those n bytes and a
// block with the remainder. the latter may be nil.
func (hc *halfConn) splitBlock(b *block, n int) (*block, *block) {
if len(b.data) <= n {
return b, nil
}
bb := hc.newBlock()
bb.resize(len(b.data) - n)
copy(bb.data, b.data[n:])
b.data = b.data[0:n]
return b, bb
}
func (c *Conn) useInTrafficSecret(version uint16, suite *cipherSuite, secret []byte) error {
if c.hand.Len() != 0 {
return c.in.setErrorLocked(errors.New("tls: buffered handshake messages on cipher change"))
}
side := serverWrite
if !c.isClient {
side = clientWrite
}
c.in.useTrafficSecret(version, suite, secret, side)
c.seenHandshakePackEnd = false
return nil
}
func (c *Conn) useOutTrafficSecret(version uint16, suite *cipherSuite, secret []byte) {
side := serverWrite
if c.isClient {
side = clientWrite
}
c.out.useTrafficSecret(version, suite, secret, side)
}
func (c *Conn) doReadRecord(want recordType) (recordType, *block, error) {
RestartReadRecord:
if c.isDTLS {
return c.dtlsDoReadRecord(want)
}
recordHeaderLen := c.in.recordHeaderLen()
if c.rawInput == nil {
c.rawInput = c.in.newBlock()
}
b := c.rawInput
// Read header, payload.
if err := b.readFromUntil(c.conn, recordHeaderLen); err != nil {
// RFC suggests that EOF without an alertCloseNotify is
// an error, but popular web sites seem to do this,
// so we can't make it an error, outside of tests.
if err == io.EOF && c.config.Bugs.ExpectCloseNotify {
err = io.ErrUnexpectedEOF
}
if e, ok := err.(net.Error); !ok || !e.Temporary() {
c.in.setErrorLocked(err)
}
return 0, nil, err
}
typ := recordType(b.data[0])
// No valid TLS record has a type of 0x80, however SSLv2 handshakes
// start with a uint16 length where the MSB is set and the first record
// is always < 256 bytes long. Therefore typ == 0x80 strongly suggests
// an SSLv2 client.
if want == recordTypeHandshake && typ == 0x80 {
c.sendAlert(alertProtocolVersion)
return 0, nil, c.in.setErrorLocked(errors.New("tls: unsupported SSLv2 handshake received"))
}
vers := uint16(b.data[1])<<8 | uint16(b.data[2])
n := int(b.data[3])<<8 | int(b.data[4])
// Alerts sent near version negotiation do not have a well-defined
// record-layer version prior to TLS 1.3. (In TLS 1.3, the record-layer
// version is irrelevant.)
if typ != recordTypeAlert {
var expect uint16
if c.haveVers {
expect = c.vers
if c.vers >= VersionTLS13 {
expect = VersionTLS12
}
} else {
expect = c.config.Bugs.ExpectInitialRecordVersion
}
if expect != 0 && vers != expect {
c.sendAlert(alertProtocolVersion)
return 0, nil, c.in.setErrorLocked(fmt.Errorf("tls: received record with version %x when expecting version %x", vers, expect))
}
}
if n > maxCiphertext {
c.sendAlert(alertRecordOverflow)
return 0, nil, c.in.setErrorLocked(fmt.Errorf("tls: oversized record received with length %d", n))
}
if !c.haveVers {
// First message, be extra suspicious:
// this might not be a TLS client.
// Bail out before reading a full 'body', if possible.
// The current max version is 3.1.
// If the version is >= 16.0, it's probably not real.
// Similarly, a clientHello message encodes in
// well under a kilobyte. If the length is >= 12 kB,
// it's probably not real.
if (typ != recordTypeAlert && typ != want) || vers >= 0x1000 || n >= 0x3000 {
c.sendAlert(alertUnexpectedMessage)
return 0, nil, c.in.setErrorLocked(fmt.Errorf("tls: first record does not look like a TLS handshake"))
}
}
if err := b.readFromUntil(c.conn, recordHeaderLen+n); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
if e, ok := err.(net.Error); !ok || !e.Temporary() {
c.in.setErrorLocked(err)
}
return 0, nil, err
}
// Process message.
b, c.rawInput = c.in.splitBlock(b, recordHeaderLen+n)
ok, off, encTyp, alertValue := c.in.decrypt(b)
// Handle skipping over early data.
if !ok && c.skipEarlyData {
goto RestartReadRecord
}
// If the server is expecting a second ClientHello (in response to
// a HelloRetryRequest) and the client sends early data, there
// won't be a decryption failure but it still needs to be skipped.
if c.in.cipher == nil && typ == recordTypeApplicationData && c.skipEarlyData {
goto RestartReadRecord
}
if !ok {
return 0, nil, c.in.setErrorLocked(c.sendAlert(alertValue))
}
b.off = off
c.skipEarlyData = false
if c.vers >= VersionTLS13 && c.in.cipher != nil {
if typ != recordTypeApplicationData {
return 0, nil, c.in.setErrorLocked(fmt.Errorf("tls: outer record type is not application data"))
}
typ = encTyp
}
length := len(b.data[b.off:])
if c.config.Bugs.ExpectRecordSplitting && typ == recordTypeApplicationData && length != 1 && !c.seenOneByteRecord {
return 0, nil, c.in.setErrorLocked(fmt.Errorf("tls: application data records were not split"))
}
c.seenOneByteRecord = typ == recordTypeApplicationData && length == 1
return typ, b, nil
}
func (c *Conn) readTLS13ChangeCipherSpec() error {
if !c.expectTLS13ChangeCipherSpec {
panic("c.expectTLS13ChangeCipherSpec not set")
}
// Read the ChangeCipherSpec.
if c.rawInput == nil {
c.rawInput = c.in.newBlock()
}
b := c.rawInput
if err := b.readFromUntil(c.conn, 1); err != nil {
return c.in.setErrorLocked(fmt.Errorf("tls: error reading TLS 1.3 ChangeCipherSpec: %s", err))
}
if recordType(b.data[0]) == recordTypeAlert {
// If the client is sending an alert, allow the ChangeCipherSpec
// to be skipped. It may be rejecting a sufficiently malformed
// ServerHello that it can't parse out the version.
c.expectTLS13ChangeCipherSpec = false
return nil
}
if err := b.readFromUntil(c.conn, 6); err != nil {
return c.in.setErrorLocked(fmt.Errorf("tls: error reading TLS 1.3 ChangeCipherSpec: %s", err))
}
// Check they match that we expect.
expected := [6]byte{byte(recordTypeChangeCipherSpec), 3, 1, 0, 1, 1}
if c.vers >= VersionTLS13 {
expected[2] = 3
}
if !bytes.Equal(b.data[:6], expected[:]) {
return c.in.setErrorLocked(fmt.Errorf("tls: error invalid TLS 1.3 ChangeCipherSpec: %x", b.data[:6]))
}
// Discard the data.
b, c.rawInput = c.in.splitBlock(b, 6)
c.in.freeBlock(b)
c.expectTLS13ChangeCipherSpec = false
return nil
}
// readRecord reads the next TLS record from the connection
// and updates the record layer state.
// c.in.Mutex <= L; c.input == nil.
func (c *Conn) readRecord(want recordType) error {
// Caller must be in sync with connection:
// handshake data if handshake not yet completed,
// else application data.
switch want {
default:
c.sendAlert(alertInternalError)
return c.in.setErrorLocked(errors.New("tls: unknown record type requested"))
case recordTypeChangeCipherSpec:
if c.handshakeComplete {
c.sendAlert(alertInternalError)
return c.in.setErrorLocked(errors.New("tls: ChangeCipherSpec requested after handshake complete"))
}
case recordTypeApplicationData, recordTypeAlert, recordTypeHandshake:
break
}
if c.expectTLS13ChangeCipherSpec {
if err := c.readTLS13ChangeCipherSpec(); err != nil {
return err
}
}
Again:
typ, b, err := c.doReadRecord(want)
if err != nil {
return err
}
data := b.data[b.off:]
max := maxPlaintext
if c.config.Bugs.MaxReceivePlaintext != 0 {
max = c.config.Bugs.MaxReceivePlaintext
}
if len(data) > max {
err := c.sendAlert(alertRecordOverflow)
c.in.freeBlock(b)
return c.in.setErrorLocked(err)
}
if typ != recordTypeHandshake {
c.seenHandshakePackEnd = false
} else if c.seenHandshakePackEnd {
c.in.freeBlock(b)
return c.in.setErrorLocked(errors.New("tls: peer violated ExpectPackedEncryptedHandshake"))
}
switch typ {
default:
c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
case recordTypeAlert:
if len(data) != 2 {
c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
break
}
if alert(data[1]) == alertCloseNotify {
c.in.setErrorLocked(io.EOF)
break
}
switch data[0] {
case alertLevelWarning:
if alert(data[1]) == alertNoCertificate {
c.in.freeBlock(b)
return errNoCertificateAlert
}
if alert(data[1]) == alertEndOfEarlyData {
c.in.freeBlock(b)
return errEndOfEarlyDataAlert
}
// drop on the floor
c.in.freeBlock(b)
goto Again
case alertLevelError:
c.in.setErrorLocked(&net.OpError{Op: "remote error", Err: alert(data[1])})
default:
c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
}
case recordTypeChangeCipherSpec:
if typ != want || len(data) != 1 || data[0] != 1 {
c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
break
}
if c.hand.Len() != 0 {
c.in.setErrorLocked(errors.New("tls: buffered handshake messages on cipher change"))
break
}
if err := c.in.changeCipherSpec(c.config); err != nil {
c.in.setErrorLocked(c.sendAlert(err.(alert)))
}
case recordTypeApplicationData:
if typ != want {
c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
break
}
c.input = b
b = nil
case recordTypeHandshake:
// Allow handshake data while reading application data to
// trigger post-handshake messages.
// TODO(rsc): Should at least pick off connection close.
if typ != want && want != recordTypeApplicationData {
return c.in.setErrorLocked(c.sendAlert(alertNoRenegotiation))
}
c.hand.Write(data)
if pack := c.config.Bugs.ExpectPackedEncryptedHandshake; pack > 0 && len(data) < pack && c.out.cipher != nil {
c.seenHandshakePackEnd = true
}
}
if b != nil {
c.in.freeBlock(b)
}
return c.in.err
}
// sendAlert sends a TLS alert message.
// c.out.Mutex <= L.
func (c *Conn) sendAlertLocked(level byte, err alert) error {
c.tmp[0] = level
c.tmp[1] = byte(err)
if c.config.Bugs.FragmentAlert {
c.writeRecord(recordTypeAlert, c.tmp[0:1])
c.writeRecord(recordTypeAlert, c.tmp[1:2])
} else if c.config.Bugs.DoubleAlert {
copy(c.tmp[2:4], c.tmp[0:2])
c.writeRecord(recordTypeAlert, c.tmp[0:4])
} else {
c.writeRecord(recordTypeAlert, c.tmp[0:2])
}
// Error alerts are fatal to the connection.
if level == alertLevelError {
return c.out.setErrorLocked(&net.OpError{Op: "local error", Err: err})
}
return nil
}
// sendAlert sends a TLS alert message.
// L < c.out.Mutex.
func (c *Conn) sendAlert(err alert) error {
level := byte(alertLevelError)
if err == alertNoRenegotiation || err == alertCloseNotify || err == alertNoCertificate || err == alertEndOfEarlyData {
level = alertLevelWarning
}
return c.SendAlert(level, err)
}
func (c *Conn) SendAlert(level byte, err alert) error {
c.out.Lock()
defer c.out.Unlock()
return c.sendAlertLocked(level, err)
}
// writeV2Record writes a record for a V2ClientHello.
func (c *Conn) writeV2Record(data []byte) (n int, err error) {
record := make([]byte, 2+len(data))
record[0] = uint8(len(data)>>8) | 0x80
record[1] = uint8(len(data))
copy(record[2:], data)
return c.conn.Write(record)
}
// writeRecord writes a TLS record with the given type and payload
// to the connection and updates the record layer state.
// c.out.Mutex <= L.
func (c *Conn) writeRecord(typ recordType, data []byte) (n int, err error) {
c.seenHandshakePackEnd = false
if typ == recordTypeHandshake {
msgType := data[0]
if c.config.Bugs.SendWrongMessageType != 0 && msgType == c.config.Bugs.SendWrongMessageType {
msgType += 42
} else if msgType == typeServerHello && c.config.Bugs.SendServerHelloAsHelloRetryRequest {
msgType = typeHelloRetryRequest
}
if msgType != data[0] {
newData := make([]byte, len(data))
copy(newData, data)
newData[0] = msgType
data = newData
}
if c.config.Bugs.SendTrailingMessageData != 0 && msgType == c.config.Bugs.SendTrailingMessageData {
newData := make([]byte, len(data))
copy(newData, data)
// Add a 0 to the body.
newData = append(newData, 0)
// Fix the header.
newLen := len(newData) - 4
newData[1] = byte(newLen >> 16)
newData[2] = byte(newLen >> 8)
newData[3] = byte(newLen)
data = newData
}
}
if c.isDTLS {
return c.dtlsWriteRecord(typ, data)
}
if typ == recordTypeHandshake {
if c.config.Bugs.SendHelloRequestBeforeEveryHandshakeMessage {
newData := make([]byte, 0, 4+len(data))
newData = append(newData, typeHelloRequest, 0, 0, 0)
newData = append(newData, data...)
data = newData
}
if c.config.Bugs.PackHandshakeFlight {
c.pendingFlight.Write(data)
return len(data), nil
}
}
// Flush buffered data before writing anything.
if err := c.flushHandshake(); err != nil {
return 0, err
}
if typ == recordTypeApplicationData && c.config.Bugs.SendPostHandshakeChangeCipherSpec {
if _, err := c.doWriteRecord(recordTypeChangeCipherSpec, []byte{1}); err != nil {
return 0, err
}
}
return c.doWriteRecord(typ, data)
}
func (c *Conn) doWriteRecord(typ recordType, data []byte) (n int, err error) {
recordHeaderLen := c.out.recordHeaderLen()
b := c.out.newBlock()
first := true
isClientHello := typ == recordTypeHandshake && len(data) > 0 && data[0] == typeClientHello
for len(data) > 0 || first {
m := len(data)
if m > maxPlaintext && !c.config.Bugs.SendLargeRecords {
m = maxPlaintext
}
if typ == recordTypeHandshake && c.config.Bugs.MaxHandshakeRecordLength > 0 && m > c.config.Bugs.MaxHandshakeRecordLength {
m = c.config.Bugs.MaxHandshakeRecordLength
// By default, do not fragment the client_version or
// server_version, which are located in the first 6
// bytes.
if first && isClientHello && !c.config.Bugs.FragmentClientVersion && m < 6 {
m = 6
}
}
explicitIVLen := 0
explicitIVIsSeq := false
first = false
var cbc cbcMode
if c.out.version >= VersionTLS11 {
var ok bool
if cbc, ok = c.out.cipher.(cbcMode); ok {
explicitIVLen = cbc.BlockSize()
}
}
if explicitIVLen == 0 {
if aead, ok := c.out.cipher.(*tlsAead); ok && aead.explicitNonce {
explicitIVLen = 8
// The AES-GCM construction in TLS has an
// explicit nonce so that the nonce can be
// random. However, the nonce is only 8 bytes
// which is too small for a secure, random
// nonce. Therefore we use the sequence number
// as the nonce.
explicitIVIsSeq = true
}
}
b.resize(recordHeaderLen + explicitIVLen + m)
b.data[0] = byte(typ)
if c.vers >= VersionTLS13 && c.out.cipher != nil {
b.data[0] = byte(recordTypeApplicationData)
if outerType := c.config.Bugs.OuterRecordType; outerType != 0 {
b.data[0] = byte(outerType)
}
}
vers := c.vers
if vers == 0 {
// Some TLS servers fail if the record version is
// greater than TLS 1.0 for the initial ClientHello.
//
// TLS 1.3 fixes the version number in the record
// layer to {3, 1}.
vers = VersionTLS10
}
if c.vers >= VersionTLS13 || c.out.version >= VersionTLS13 {
vers = VersionTLS12
}
if c.config.Bugs.SendRecordVersion != 0 {
vers = c.config.Bugs.SendRecordVersion
}
if c.vers == 0 && c.config.Bugs.SendInitialRecordVersion != 0 {
vers = c.config.Bugs.SendInitialRecordVersion
}
b.data[1] = byte(vers >> 8)
b.data[2] = byte(vers)
b.data[3] = byte(m >> 8)
b.data[4] = byte(m)
if explicitIVLen > 0 {
explicitIV := b.data[recordHeaderLen : recordHeaderLen+explicitIVLen]
if explicitIVIsSeq {
copy(explicitIV, c.out.seq[:])
} else {
if _, err = io.ReadFull(c.config.rand(), explicitIV); err != nil {
break
}
}
}
copy(b.data[recordHeaderLen+explicitIVLen:], data)
c.out.encrypt(b, explicitIVLen, typ)
_, err = c.conn.Write(b.data)
if err != nil {
break
}
n += m
data = data[m:]
}
c.out.freeBlock(b)
if typ == recordTypeChangeCipherSpec && c.vers < VersionTLS13 {
err = c.out.changeCipherSpec(c.config)
if err != nil {
return n, c.sendAlertLocked(alertLevelError, err.(alert))
}
}
return
}
func (c *Conn) flushHandshake() error {
if c.isDTLS {
return c.dtlsFlushHandshake()
}
for c.pendingFlight.Len() > 0 {
var buf [maxPlaintext]byte
n, _ := c.pendingFlight.Read(buf[:])
if _, err := c.doWriteRecord(recordTypeHandshake, buf[:n]); err != nil {
return err
}
}
c.pendingFlight.Reset()
return nil
}
func (c *Conn) doReadHandshake() ([]byte, error) {
if c.isDTLS {
return c.dtlsDoReadHandshake()
}
for c.hand.Len() < 4 {
if err := c.in.err; err != nil {
return nil, err
}
if err := c.readRecord(recordTypeHandshake); err != nil {
return nil, err
}
}
data := c.hand.Bytes()
n := int(data[1])<<16 | int(data[2])<<8 | int(data[3])
if n > maxHandshake {
return nil, c.in.setErrorLocked(c.sendAlert(alertInternalError))
}
for c.hand.Len() < 4+n {
if err := c.in.err; err != nil {
return nil, err
}
if err := c.readRecord(recordTypeHandshake); err != nil {
return nil, err
}
}
return c.hand.Next(4 + n), nil
}
// readHandshake reads the next handshake message from
// the record layer.
// c.in.Mutex < L; c.out.Mutex < L.
func (c *Conn) readHandshake() (interface{}, error) {
data, err := c.doReadHandshake()
if err == errNoCertificateAlert {
if c.hand.Len() != 0 {
// The warning alert may not interleave with a handshake message.
return nil, c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
}
return new(ssl3NoCertificateMsg), nil
}
if err != nil {
return nil, err
}
var m handshakeMessage
switch data[0] {
case typeHelloRequest:
m = new(helloRequestMsg)
case typeClientHello:
m = &clientHelloMsg{
isDTLS: c.isDTLS,
}
case typeServerHello:
m = &serverHelloMsg{
isDTLS: c.isDTLS,
}
case typeHelloRetryRequest:
m = new(helloRetryRequestMsg)
case typeNewSessionTicket:
m = &newSessionTicketMsg{
vers: c.wireVersion,
isDTLS: c.isDTLS,
}
case typeEncryptedExtensions:
m = new(encryptedExtensionsMsg)
case typeCertificate:
m = &certificateMsg{
hasRequestContext: c.vers >= VersionTLS13,
}
case typeCompressedCertificate:
m = new(compressedCertificateMsg)
case typeCertificateRequest:
m = &certificateRequestMsg{
vers: c.wireVersion,
hasSignatureAlgorithm: c.vers >= VersionTLS12,
hasRequestContext: c.vers >= VersionTLS13,
}
case typeCertificateStatus:
m = new(certificateStatusMsg)
case typeServerKeyExchange:
m = new(serverKeyExchangeMsg)
case typeServerHelloDone:
m = new(serverHelloDoneMsg)
case typeClientKeyExchange:
m = new(clientKeyExchangeMsg)
case typeCertificateVerify:
m = &certificateVerifyMsg{
hasSignatureAlgorithm: c.vers >= VersionTLS12,
}
case typeNextProtocol:
m = new(nextProtoMsg)
case typeFinished:
m = new(finishedMsg)
case typeHelloVerifyRequest:
m = new(helloVerifyRequestMsg)
case typeChannelID:
m = new(channelIDMsg)
case typeKeyUpdate:
m = new(keyUpdateMsg)
case typeEndOfEarlyData:
m = new(endOfEarlyDataMsg)
default:
return nil, c.in.setErrorLocked(c.sendAlert(alertUnexpectedMessage))
}
// The handshake message unmarshallers
// expect to be able to keep references to data,
// so pass in a fresh copy that won't be overwritten.
data = append([]byte(nil), data...)
if data[0] == typeServerHello && len(data) >= 38 {
vers := uint16(data[4])<<8 | uint16(data[5])
if vers == VersionTLS12 && bytes.Equal(data[6:38], tls13HelloRetryRequest) {
m = new(helloRetryRequestMsg)
m.(*helloRetryRequestMsg).isServerHello = true
}
}
if !m.unmarshal(data) {
return nil, c.in.setErrorLocked(c.sendAlert(alertDecodeError))
}
return m, nil
}
// skipPacket processes all the DTLS records in packet. It updates
// sequence number expectations but otherwise ignores them.
func (c *Conn) skipPacket(packet []byte) error {
for len(packet) > 0 {
if len(packet) < 13 {
return errors.New("tls: bad packet")
}
// Dropped packets are completely ignored save to update
// expected sequence numbers for this and the next epoch. (We
// don't assert on the contents of the packets both for
// simplicity and because a previous test with one shorter
// timeout schedule would have done so.)
epoch := packet[3:5]
seq := packet[5:11]
length := uint16(packet[11])<<8 | uint16(packet[12])
if bytes.Equal(c.in.seq[:2], epoch) {
if bytes.Compare(seq, c.in.seq[2:]) < 0 {
return errors.New("tls: sequence mismatch")
}
copy(c.in.seq[2:], seq)
c.in.incSeq(false)
} else {
if bytes.Compare(seq, c.in.nextSeq[:]) < 0 {
return errors.New("tls: sequence mismatch")
}
copy(c.in.nextSeq[:], seq)
c.in.incNextSeq()
}
if len(packet) < 13+int(length) {
return errors.New("tls: bad packet")
}
packet = packet[13+length:]
}
return nil
}
// simulatePacketLoss simulates the loss of a handshake leg from the
// peer based on the schedule in c.config.Bugs. If resendFunc is
// non-nil, it is called after each simulated timeout to retransmit
// handshake messages from the local end. This is used in cases where
// the peer retransmits on a stale Finished rather than a timeout.
func (c *Conn) simulatePacketLoss(resendFunc func()) error {
if len(c.config.Bugs.TimeoutSchedule) == 0 {
return nil
}
if !c.isDTLS {
return errors.New("tls: TimeoutSchedule may only be set in DTLS")
}
if c.config.Bugs.PacketAdaptor == nil {
return errors.New("tls: TimeoutSchedule set without PacketAdapter")
}
for _, timeout := range c.config.Bugs.TimeoutSchedule {
// Simulate a timeout.
packets, err := c.config.Bugs.PacketAdaptor.SendReadTimeout(timeout)
if err != nil {
return err
}
for _, packet := range packets {
if err := c.skipPacket(packet); err != nil {
return err
}
}
if resendFunc != nil {
resendFunc()
}
}
return nil
}
func (c *Conn) SendHalfHelloRequest() error {
if err := c.Handshake(); err != nil {
return err
}
c.out.Lock()
defer c.out.Unlock()
if _, err := c.writeRecord(recordTypeHandshake, []byte{typeHelloRequest, 0}); err != nil {
return err
}
return c.flushHandshake()
}
// Write writes data to the connection.
func (c *Conn) Write(b []byte) (int, error) {
if err := c.Handshake(); err != nil {
return 0, err
}
c.out.Lock()
defer c.out.Unlock()
if err := c.out.err; err != nil {
return 0, err
}
if !c.handshakeComplete {
return 0, alertInternalError
}
if c.keyUpdateRequested {
if err := c.sendKeyUpdateLocked(keyUpdateNotRequested); err != nil {
return 0, err
}
c.keyUpdateRequested = false
}
if c.config.Bugs.SendSpuriousAlert != 0 {
c.sendAlertLocked(alertLevelError, c.config.Bugs.SendSpuriousAlert)
}
if c.config.Bugs.SendHelloRequestBeforeEveryAppDataRecord {
c.writeRecord(recordTypeHandshake, []byte{typeHelloRequest, 0, 0, 0})
c.flushHandshake()
}
// SSL 3.0 and TLS 1.0 are susceptible to a chosen-plaintext
// attack when using block mode ciphers due to predictable IVs.
// This can be prevented by splitting each Application Data
// record into two records, effectively randomizing the IV.
//
// http://www.openssl.org/~bodo/tls-cbc.txt
// https://bugzilla.mozilla.org/show_bug.cgi?id=665814
// http://www.imperialviolet.org/2012/01/15/beastfollowup.html
var m int
if len(b) > 1 && c.vers <= VersionTLS10 && !c.isDTLS {
if _, ok := c.out.cipher.(cipher.BlockMode); ok {
n, err := c.writeRecord(recordTypeApplicationData, b[:1])
if err != nil {
return n, c.out.setErrorLocked(err)
}
m, b = 1, b[1:]
}
}
n, err := c.writeRecord(recordTypeApplicationData, b)
return n + m, c.out.setErrorLocked(err)
}
func (c *Conn) processTLS13NewSessionTicket(newSessionTicket *newSessionTicketMsg, cipherSuite *cipherSuite) error {
if c.config.Bugs.ExpectGREASE && !newSessionTicket.hasGREASEExtension {
return errors.New("tls: no GREASE ticket extension found")
}
if c.config.Bugs.ExpectTicketEarlyData && newSessionTicket.maxEarlyDataSize == 0 {
return errors.New("tls: no early_data ticket extension found")
}
if c.config.Bugs.ExpectNoNewSessionTicket {
return errors.New("tls: received unexpected NewSessionTicket")
}
if c.config.ClientSessionCache == nil || newSessionTicket.ticketLifetime == 0 {
return nil
}
session := &ClientSessionState{
sessionTicket: newSessionTicket.ticket,
vers: c.vers,
wireVersion: c.wireVersion,
cipherSuite: cipherSuite.id,
masterSecret: c.resumptionSecret,
serverCertificates: c.peerCertificates,
sctList: c.sctList,
ocspResponse: c.ocspResponse,
ticketCreationTime: c.config.time(),
ticketExpiration: c.config.time().Add(time.Duration(newSessionTicket.ticketLifetime) * time.Second),
ticketAgeAdd: newSessionTicket.ticketAgeAdd,
maxEarlyDataSize: newSessionTicket.maxEarlyDataSize,
earlyALPN: c.clientProtocol,
}
session.masterSecret = deriveSessionPSK(cipherSuite, c.wireVersion, c.resumptionSecret, newSessionTicket.ticketNonce)
cacheKey := clientSessionCacheKey(c.conn.RemoteAddr(), c.config)
_, ok := c.config.ClientSessionCache.Get(cacheKey)
if !ok || !c.config.Bugs.UseFirstSessionTicket {
c.config.ClientSessionCache.Put(cacheKey, session)
}
return nil
}
func (c *Conn) handlePostHandshakeMessage() error {
msg, err := c.readHandshake()
if err != nil {
return err
}
if c.vers < VersionTLS13 {
if !c.isClient {
c.sendAlert(alertUnexpectedMessage)
return errors.New("tls: unexpected post-handshake message")
}
_, ok := msg.(*helloRequestMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return alertUnexpectedMessage
}
c.handshakeComplete = false
return c.Handshake()
}
if c.isClient {
if newSessionTicket, ok := msg.(*newSessionTicketMsg); ok {
return c.processTLS13NewSessionTicket(newSessionTicket, c.cipherSuite)
}
}
if keyUpdate, ok := msg.(*keyUpdateMsg); ok {
c.keyUpdateSeen = true
if c.config.Bugs.RejectUnsolicitedKeyUpdate {
return errors.New("tls: unexpected KeyUpdate message")
}
if err := c.useInTrafficSecret(c.in.wireVersion, c.cipherSuite, updateTrafficSecret(c.cipherSuite.hash(), c.wireVersion, c.in.trafficSecret)); err != nil {
return err
}
if keyUpdate.keyUpdateRequest == keyUpdateRequested {
c.keyUpdateRequested = true
}
return nil
}
c.sendAlert(alertUnexpectedMessage)
return errors.New("tls: unexpected post-handshake message")
}
// Reads a KeyUpdate acknowledgment from the peer. There may not be any
// application data records before the message.
func (c *Conn) ReadKeyUpdateACK() error {
c.in.Lock()
defer c.in.Unlock()
msg, err := c.readHandshake()
if err != nil {
return err
}
keyUpdate, ok := msg.(*keyUpdateMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return fmt.Errorf("tls: unexpected message (%T) when reading KeyUpdate", msg)
}
if keyUpdate.keyUpdateRequest != keyUpdateNotRequested {
return errors.New("tls: received invalid KeyUpdate message")
}
return c.useInTrafficSecret(c.in.wireVersion, c.cipherSuite, updateTrafficSecret(c.cipherSuite.hash(), c.wireVersion, c.in.trafficSecret))
}
func (c *Conn) Renegotiate() error {
if !c.isClient {
helloReq := new(helloRequestMsg).marshal()
if c.config.Bugs.BadHelloRequest != nil {
helloReq = c.config.Bugs.BadHelloRequest
}
c.writeRecord(recordTypeHandshake, helloReq)
c.flushHandshake()
}
c.handshakeComplete = false
return c.Handshake()
}
// Read can be made to time out and return a net.Error with Timeout() == true
// after a fixed time limit; see SetDeadline and SetReadDeadline.
func (c *Conn) Read(b []byte) (n int, err error) {
if err = c.Handshake(); err != nil {
return
}
c.in.Lock()
defer c.in.Unlock()
// Some OpenSSL servers send empty records in order to randomize the
// CBC IV. So this loop ignores a limited number of empty records.
const maxConsecutiveEmptyRecords = 100
for emptyRecordCount := 0; emptyRecordCount <= maxConsecutiveEmptyRecords; emptyRecordCount++ {
for c.input == nil && c.in.err == nil {
if err := c.readRecord(recordTypeApplicationData); err != nil {
// Soft error, like EAGAIN
return 0, err
}
for c.hand.Len() > 0 {
// We received handshake bytes, indicating a
// post-handshake message.
if err := c.handlePostHandshakeMessage(); err != nil {
return 0, err
}
}
}
if err := c.in.err; err != nil {
return 0, err
}
n, err = c.input.Read(b)
if c.input.off >= len(c.input.data) || c.isDTLS {
c.in.freeBlock(c.input)
c.input = nil
}
// If a close-notify alert is waiting, read it so that
// we can return (n, EOF) instead of (n, nil), to signal
// to the HTTP response reading goroutine that the
// connection is now closed. This eliminates a race
// where the HTTP response reading goroutine would
// otherwise not observe the EOF until its next read,
// by which time a client goroutine might have already
// tried to reuse the HTTP connection for a new
// request.
// See https://codereview.appspot.com/76400046
// and http://golang.org/issue/3514
if ri := c.rawInput; ri != nil &&
n != 0 && err == nil &&
c.input == nil && len(ri.data) > 0 && recordType(ri.data[0]) == recordTypeAlert {
if recErr := c.readRecord(recordTypeApplicationData); recErr != nil {
err = recErr // will be io.EOF on closeNotify
}
}
if n != 0 || err != nil {
return n, err
}
}
return 0, io.ErrNoProgress
}
// Close closes the connection.
func (c *Conn) Close() error {
var alertErr error
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
if c.handshakeComplete && !c.config.Bugs.NoCloseNotify {
alert := alertCloseNotify
if c.config.Bugs.SendAlertOnShutdown != 0 {
alert = c.config.Bugs.SendAlertOnShutdown
}
alertErr = c.sendAlert(alert)
// Clear local alerts when sending alerts so we continue to wait
// for the peer rather than closing the socket early.
if opErr, ok := alertErr.(*net.OpError); ok && opErr.Op == "local error" {
alertErr = nil
}
}
// Consume a close_notify from the peer if one hasn't been received
// already. This avoids the peer from failing |SSL_shutdown| due to a
// write failing.
if c.handshakeComplete && alertErr == nil && c.config.Bugs.ExpectCloseNotify {
for c.in.error() == nil {
c.readRecord(recordTypeAlert)
}
if c.in.error() != io.EOF {
alertErr = c.in.error()
}
}
if err := c.conn.Close(); err != nil {
return err
}
return alertErr
}
// Handshake runs the client or server handshake
// protocol if it has not yet been run.
// Most uses of this package need not call Handshake
// explicitly: the first Read or Write will call it automatically.
func (c *Conn) Handshake() error {
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
if err := c.handshakeErr; err != nil {
return err
}
if c.handshakeComplete {
return nil
}
if c.isDTLS && c.config.Bugs.SendSplitAlert {
c.conn.Write([]byte{
byte(recordTypeAlert), // type
0xfe, 0xff, // version
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, // sequence
0x0, 0x2, // length
})
c.conn.Write([]byte{alertLevelError, byte(alertInternalError)})
}
if data := c.config.Bugs.AppDataBeforeHandshake; data != nil {
c.writeRecord(recordTypeApplicationData, data)
}
if c.isClient {
c.handshakeErr = c.clientHandshake()
} else {
c.handshakeErr = c.serverHandshake()
}
if c.handshakeErr == nil && c.config.Bugs.SendInvalidRecordType {
c.writeRecord(recordType(42), []byte("invalid record"))
}
return c.handshakeErr
}
// ConnectionState returns basic TLS details about the connection.
func (c *Conn) ConnectionState() ConnectionState {
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
var state ConnectionState
state.HandshakeComplete = c.handshakeComplete
if c.handshakeComplete {
state.Version = c.vers
state.NegotiatedProtocol = c.clientProtocol
state.DidResume = c.didResume
state.NegotiatedProtocolIsMutual = !c.clientProtocolFallback
state.NegotiatedProtocolFromALPN = c.usedALPN
state.CipherSuite = c.cipherSuite.id
state.PeerCertificates = c.peerCertificates
state.VerifiedChains = c.verifiedChains
state.ServerName = c.serverName
state.ChannelID = c.channelID
state.TokenBindingNegotiated = c.tokenBindingNegotiated
state.TokenBindingParam = c.tokenBindingParam
state.SRTPProtectionProfile = c.srtpProtectionProfile
state.TLSUnique = c.firstFinished[:]
state.SCTList = c.sctList
state.PeerSignatureAlgorithm = c.peerSignatureAlgorithm
state.CurveID = c.curveID
state.QUICTransportParams = c.quicTransportParams
}
return state
}
// OCSPResponse returns the stapled OCSP response from the TLS server, if
// any. (Only valid for client connections.)
func (c *Conn) OCSPResponse() []byte {
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
return c.ocspResponse
}
// VerifyHostname checks that the peer certificate chain is valid for
// connecting to host. If so, it returns nil; if not, it returns an error
// describing the problem.
func (c *Conn) VerifyHostname(host string) error {
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
if !c.isClient {
return errors.New("tls: VerifyHostname called on TLS server connection")
}
if !c.handshakeComplete {
return errors.New("tls: handshake has not yet been performed")
}
return c.peerCertificates[0].VerifyHostname(host)
}
func (c *Conn) exportKeyingMaterialTLS13(length int, secret, label, context []byte) []byte {
cipherSuite := c.cipherSuite
if cipherSuite == nil {
cipherSuite = c.earlyCipherSuite
}
hash := cipherSuite.hash()
exporterKeyingLabel := []byte("exporter")
contextHash := hash.New()
contextHash.Write(context)
exporterContext := hash.New().Sum(nil)
derivedSecret := hkdfExpandLabel(cipherSuite.hash(), secret, label, exporterContext, hash.Size())
return hkdfExpandLabel(cipherSuite.hash(), derivedSecret, exporterKeyingLabel, contextHash.Sum(nil), length)
}
// ExportKeyingMaterial exports keying material from the current connection
// state, as per RFC 5705.
func (c *Conn) ExportKeyingMaterial(length int, label, context []byte, useContext bool) ([]byte, error) {
c.handshakeMutex.Lock()
defer c.handshakeMutex.Unlock()
if !c.handshakeComplete {
return nil, errors.New("tls: handshake has not yet been performed")
}
if c.vers >= VersionTLS13 {
return c.exportKeyingMaterialTLS13(length, c.exporterSecret, label, context), nil
}
seedLen := len(c.clientRandom) + len(c.serverRandom)
if useContext {
seedLen += 2 + len(context)
}
seed := make([]byte, 0, seedLen)
seed = append(seed, c.clientRandom[:]...)
seed = append(seed, c.serverRandom[:]...)
if useContext {
seed = append(seed, byte(len(context)>>8), byte(len(context)))
seed = append(seed, context...)
}
result := make([]byte, length)
prfForVersion(c.vers, c.cipherSuite)(result, c.exporterSecret, label, seed)
return result, nil
}
func (c *Conn) ExportEarlyKeyingMaterial(length int, label, context []byte) ([]byte, error) {
if c.vers < VersionTLS13 {
return nil, errors.New("tls: early exporters not defined before TLS 1.3")
}
if c.earlyExporterSecret == nil {
return nil, errors.New("tls: no early exporter secret")
}
return c.exportKeyingMaterialTLS13(length, c.earlyExporterSecret, label, context), nil
}
// noRenegotiationInfo returns true if the renegotiation info extension
// should be supported in the current handshake.
func (c *Conn) noRenegotiationInfo() bool {
if c.config.Bugs.NoRenegotiationInfo {
return true
}
if c.cipherSuite == nil && c.config.Bugs.NoRenegotiationInfoInInitial {
return true
}
if c.cipherSuite != nil && c.config.Bugs.NoRenegotiationInfoAfterInitial {
return true
}
return false
}
func (c *Conn) SendNewSessionTicket(nonce []byte) error {
if c.isClient || c.vers < VersionTLS13 {
return errors.New("tls: cannot send post-handshake NewSessionTicket")
}
var peerCertificatesRaw [][]byte
for _, cert := range c.peerCertificates {
peerCertificatesRaw = append(peerCertificatesRaw, cert.Raw)
}
addBuffer := make([]byte, 4)
_, err := io.ReadFull(c.config.rand(), addBuffer)
if err != nil {
c.sendAlert(alertInternalError)
return errors.New("tls: short read from Rand: " + err.Error())
}
ticketAgeAdd := uint32(addBuffer[3])<<24 | uint32(addBuffer[2])<<16 | uint32(addBuffer[1])<<8 | uint32(addBuffer[0])
// TODO(davidben): Allow configuring these values.
m := &newSessionTicketMsg{
vers: c.wireVersion,
isDTLS: c.isDTLS,
ticketLifetime: uint32(24 * time.Hour / time.Second),
duplicateEarlyDataExtension: c.config.Bugs.DuplicateTicketEarlyData,
customExtension: c.config.Bugs.CustomTicketExtension,
ticketAgeAdd: ticketAgeAdd,
ticketNonce: nonce,
maxEarlyDataSize: c.config.MaxEarlyDataSize,
}
if c.config.Bugs.SendTicketLifetime != 0 {
m.ticketLifetime = uint32(c.config.Bugs.SendTicketLifetime / time.Second)
}
state := sessionState{
vers: c.vers,
cipherSuite: c.cipherSuite.id,
masterSecret: deriveSessionPSK(c.cipherSuite, c.wireVersion, c.resumptionSecret, nonce),
certificates: peerCertificatesRaw,
ticketCreationTime: c.config.time(),
ticketExpiration: c.config.time().Add(time.Duration(m.ticketLifetime) * time.Second),
ticketAgeAdd: uint32(addBuffer[3])<<24 | uint32(addBuffer[2])<<16 | uint32(addBuffer[1])<<8 | uint32(addBuffer[0]),
earlyALPN: []byte(c.clientProtocol),
}
if !c.config.Bugs.SendEmptySessionTicket {
var err error
m.ticket, err = c.encryptTicket(&state)
if err != nil {
return err
}
}
c.out.Lock()
defer c.out.Unlock()
_, err = c.writeRecord(recordTypeHandshake, m.marshal())
return err
}
func (c *Conn) SendKeyUpdate(keyUpdateRequest byte) error {
c.out.Lock()
defer c.out.Unlock()
return c.sendKeyUpdateLocked(keyUpdateRequest)
}
func (c *Conn) sendKeyUpdateLocked(keyUpdateRequest byte) error {
if c.vers < VersionTLS13 {
return errors.New("tls: attempted to send KeyUpdate before TLS 1.3")
}
m := keyUpdateMsg{
keyUpdateRequest: keyUpdateRequest,
}
if _, err := c.writeRecord(recordTypeHandshake, m.marshal()); err != nil {
return err
}
if err := c.flushHandshake(); err != nil {
return err
}
c.useOutTrafficSecret(c.out.wireVersion, c.cipherSuite, updateTrafficSecret(c.cipherSuite.hash(), c.wireVersion, c.out.trafficSecret))
return nil
}
func (c *Conn) sendFakeEarlyData(len int) error {
// Assemble a fake early data record. This does not use writeRecord
// because the record layer may be using different keys at this point.
payload := make([]byte, 5+len)
payload[0] = byte(recordTypeApplicationData)
payload[1] = 3
payload[2] = 3
payload[3] = byte(len >> 8)
payload[4] = byte(len)
_, err := c.conn.Write(payload)
return err
}