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- // 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 tls
-
- import (
- "bytes"
- "crypto/cipher"
- "crypto/subtle"
- "crypto/x509"
- "errors"
- "io"
- "net"
- "sync"
- "time"
- )
-
- // A Conn represents a secured connection.
- // It implements the net.Conn interface.
- type Conn struct {
- // constant
- conn net.Conn
- isClient bool
-
- // constant after handshake; protected by handshakeMutex
- handshakeMutex sync.Mutex // handshakeMutex < in.Mutex, out.Mutex, errMutex
- vers uint16 // TLS version
- haveVers bool // version has been negotiated
- config *Config // configuration passed to constructor
- handshakeComplete bool
- didResume bool // whether this connection was a session resumption
- cipherSuite uint16
- ocspResponse []byte // stapled OCSP response
- 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
-
- clientProtocol string
- clientProtocolFallback bool
-
- // first permanent error
- connErr
-
- // input/output
- in, out halfConn // in.Mutex < out.Mutex
- rawInput *block // raw input, right off the wire
- input *block // application data waiting to be read
- hand bytes.Buffer // handshake data waiting to be read
-
- tmp [16]byte
- }
-
- type connErr struct {
- mu sync.Mutex
- value error
- }
-
- func (e *connErr) setError(err error) error {
- e.mu.Lock()
- defer e.mu.Unlock()
-
- if e.value == nil {
- e.value = err
- }
- return err
- }
-
- func (e *connErr) error() error {
- e.mu.Lock()
- defer e.mu.Unlock()
- return e.value
- }
-
- // 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
- version uint16 // protocol version
- cipher interface{} // cipher algorithm
- mac macFunction
- seq [8]byte // 64-bit sequence number
- bfree *block // list of free blocks
-
- nextCipher interface{} // next encryption state
- nextMac macFunction // next MAC algorithm
-
- // used to save allocating a new buffer for each MAC.
- inDigestBuf, outDigestBuf []byte
- }
-
- // prepareCipherSpec sets the encryption and MAC states
- // that a subsequent changeCipherSpec will use.
- func (hc *halfConn) prepareCipherSpec(version uint16, cipher interface{}, mac macFunction) {
- hc.version = version
- hc.nextCipher = cipher
- hc.nextMac = mac
- }
-
- // changeCipherSpec changes the encryption and MAC states
- // to the ones previously passed to prepareCipherSpec.
- func (hc *halfConn) changeCipherSpec() error {
- if hc.nextCipher == nil {
- return alertInternalError
- }
- hc.cipher = hc.nextCipher
- hc.mac = hc.nextMac
- hc.nextCipher = nil
- hc.nextMac = nil
- return nil
- }
-
- // incSeq increments the sequence number.
- func (hc *halfConn) incSeq() {
- for i := 7; i >= 0; i-- {
- hc.seq[i]++
- if hc.seq[i] != 0 {
- return
- }
- }
-
- // Not allowed to let sequence number wrap.
- // Instead, must renegotiate before it does.
- // Not likely enough to bother.
- panic("TLS: sequence number wraparound")
- }
-
- // resetSeq resets the sequence number to zero.
- func (hc *halfConn) resetSeq() {
- for i := range hc.seq {
- hc.seq[i] = 0
- }
- }
-
- // 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
- }
-
- // decrypt checks and strips the mac and decrypts the data in b.
- func (hc *halfConn) decrypt(b *block) (bool, alert) {
- // pull out payload
- payload := b.data[recordHeaderLen:]
-
- macSize := 0
- if hc.mac != nil {
- macSize = hc.mac.Size()
- }
-
- paddingGood := byte(255)
-
- // decrypt
- if hc.cipher != nil {
- switch c := hc.cipher.(type) {
- case cipher.Stream:
- c.XORKeyStream(payload, payload)
- case cipher.BlockMode:
- blockSize := c.BlockSize()
-
- if len(payload)%blockSize != 0 || len(payload) < roundUp(macSize+1, blockSize) {
- return false, alertBadRecordMAC
- }
-
- c.CryptBlocks(payload, payload)
- if hc.version == versionSSL30 {
- payload, paddingGood = removePaddingSSL30(payload)
- } else {
- payload, paddingGood = removePadding(payload)
- }
- b.resize(recordHeaderLen + 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.
- default:
- panic("unknown cipher type")
- }
- }
-
- // check, strip mac
- if hc.mac != nil {
- if len(payload) < macSize {
- return false, alertBadRecordMAC
- }
-
- // strip mac off payload, b.data
- n := len(payload) - macSize
- b.data[3] = byte(n >> 8)
- b.data[4] = byte(n)
- b.resize(recordHeaderLen + n)
- remoteMAC := payload[n:]
- localMAC := hc.mac.MAC(hc.inDigestBuf, hc.seq[0:], b.data)
- hc.incSeq()
-
- if subtle.ConstantTimeCompare(localMAC, remoteMAC) != 1 || paddingGood != 255 {
- return false, alertBadRecordMAC
- }
- hc.inDigestBuf = localMAC
- }
-
- return true, 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) (prefix, finalBlock []byte) {
- overrun := len(payload) % blockSize
- paddingLen := blockSize - overrun
- prefix = payload[:len(payload)-overrun]
- finalBlock = make([]byte, blockSize)
- copy(finalBlock, payload[len(payload)-overrun:])
- for i := overrun; i < blockSize; i++ {
- finalBlock[i] = byte(paddingLen - 1)
- }
- return
- }
-
- // encrypt encrypts and macs the data in b.
- func (hc *halfConn) encrypt(b *block) (bool, alert) {
- // mac
- if hc.mac != nil {
- mac := hc.mac.MAC(hc.outDigestBuf, hc.seq[0:], b.data)
- hc.incSeq()
-
- 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 {
- switch c := hc.cipher.(type) {
- case cipher.Stream:
- c.XORKeyStream(payload, payload)
- case cipher.BlockMode:
- prefix, finalBlock := padToBlockSize(payload, c.BlockSize())
- b.resize(recordHeaderLen + len(prefix) + len(finalBlock))
- c.CryptBlocks(b.data[recordHeaderLen:], prefix)
- c.CryptBlocks(b.data[recordHeaderLen+len(prefix):], finalBlock)
- default:
- panic("unknown cipher type")
- }
- }
-
- // update length to include MAC and any block padding needed.
- n := len(b.data) - recordHeaderLen
- b.data[3] = byte(n >> 8)
- b.data[4] = byte(n)
-
- 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 {
- 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
- }
-
- // 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. (We don't support renegotiation.)
- switch want {
- default:
- return c.sendAlert(alertInternalError)
- case recordTypeHandshake, recordTypeChangeCipherSpec:
- if c.handshakeComplete {
- return c.sendAlert(alertInternalError)
- }
- case recordTypeApplicationData:
- if !c.handshakeComplete {
- return c.sendAlert(alertInternalError)
- }
- }
-
- Again:
- 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.
- // if err == io.EOF {
- // err = io.ErrUnexpectedEOF
- // }
- if e, ok := err.(net.Error); !ok || !e.Temporary() {
- c.setError(err)
- }
- return 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 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])
- if c.haveVers && vers != c.vers {
- return c.sendAlert(alertProtocolVersion)
- }
- if n > maxCiphertext {
- return c.sendAlert(alertRecordOverflow)
- }
- 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 {
- return c.sendAlert(alertUnexpectedMessage)
- }
- }
- 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.setError(err)
- }
- return err
- }
-
- // Process message.
- b, c.rawInput = c.in.splitBlock(b, recordHeaderLen+n)
- b.off = recordHeaderLen
- if ok, err := c.in.decrypt(b); !ok {
- return c.sendAlert(err)
- }
- data := b.data[b.off:]
- if len(data) > maxPlaintext {
- c.sendAlert(alertRecordOverflow)
- c.in.freeBlock(b)
- return c.error()
- }
-
- switch typ {
- default:
- c.sendAlert(alertUnexpectedMessage)
-
- case recordTypeAlert:
- if len(data) != 2 {
- c.sendAlert(alertUnexpectedMessage)
- break
- }
- if alert(data[1]) == alertCloseNotify {
- c.setError(io.EOF)
- break
- }
- switch data[0] {
- case alertLevelWarning:
- // drop on the floor
- c.in.freeBlock(b)
- goto Again
- case alertLevelError:
- c.setError(&net.OpError{Op: "remote error", Err: alert(data[1])})
- default:
- c.sendAlert(alertUnexpectedMessage)
- }
-
- case recordTypeChangeCipherSpec:
- if typ != want || len(data) != 1 || data[0] != 1 {
- c.sendAlert(alertUnexpectedMessage)
- break
- }
- err := c.in.changeCipherSpec()
- if err != nil {
- c.sendAlert(err.(alert))
- }
-
- case recordTypeApplicationData:
- if typ != want {
- c.sendAlert(alertUnexpectedMessage)
- break
- }
- c.input = b
- b = nil
-
- case recordTypeHandshake:
- // TODO(rsc): Should at least pick off connection close.
- if typ != want {
- return c.sendAlert(alertNoRenegotiation)
- }
- c.hand.Write(data)
- }
-
- if b != nil {
- c.in.freeBlock(b)
- }
- return c.error()
- }
-
- // sendAlert sends a TLS alert message.
- // c.out.Mutex <= L.
- func (c *Conn) sendAlertLocked(err alert) error {
- switch err {
- case alertNoRenegotiation, alertCloseNotify:
- c.tmp[0] = alertLevelWarning
- default:
- c.tmp[0] = alertLevelError
- }
- c.tmp[1] = byte(err)
- c.writeRecord(recordTypeAlert, c.tmp[0:2])
- // closeNotify is a special case in that it isn't an error:
- if err != alertCloseNotify {
- return c.setError(&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 {
- c.out.Lock()
- defer c.out.Unlock()
- return c.sendAlertLocked(err)
- }
-
- // 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) {
- b := c.out.newBlock()
- for len(data) > 0 {
- m := len(data)
- if m > maxPlaintext {
- m = maxPlaintext
- }
- b.resize(recordHeaderLen + m)
- b.data[0] = byte(typ)
- vers := c.vers
- if vers == 0 {
- vers = maxVersion
- }
- b.data[1] = byte(vers >> 8)
- b.data[2] = byte(vers)
- b.data[3] = byte(m >> 8)
- b.data[4] = byte(m)
- copy(b.data[recordHeaderLen:], data)
- c.out.encrypt(b)
- _, err = c.conn.Write(b.data)
- if err != nil {
- break
- }
- n += m
- data = data[m:]
- }
- c.out.freeBlock(b)
-
- if typ == recordTypeChangeCipherSpec {
- err = c.out.changeCipherSpec()
- if err != nil {
- // Cannot call sendAlert directly,
- // because we already hold c.out.Mutex.
- c.tmp[0] = alertLevelError
- c.tmp[1] = byte(err.(alert))
- c.writeRecord(recordTypeAlert, c.tmp[0:2])
- return n, c.setError(&net.OpError{Op: "local error", Err: err})
- }
- }
- return
- }
-
- // readHandshake reads the next handshake message from
- // the record layer.
- // c.in.Mutex < L; c.out.Mutex < L.
- func (c *Conn) readHandshake() (interface{}, error) {
- for c.hand.Len() < 4 {
- if err := c.error(); 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 {
- c.sendAlert(alertInternalError)
- return nil, c.error()
- }
- for c.hand.Len() < 4+n {
- if err := c.error(); err != nil {
- return nil, err
- }
- if err := c.readRecord(recordTypeHandshake); err != nil {
- return nil, err
- }
- }
- data = c.hand.Next(4 + n)
- var m handshakeMessage
- switch data[0] {
- case typeClientHello:
- m = new(clientHelloMsg)
- case typeServerHello:
- m = new(serverHelloMsg)
- case typeCertificate:
- m = new(certificateMsg)
- case typeCertificateRequest:
- m = new(certificateRequestMsg)
- case typeCertificateStatus:
- m = new(certificateStatusMsg)
- case typeServerKeyExchange:
- m = new(serverKeyExchangeMsg)
- case typeServerHelloDone:
- m = new(serverHelloDoneMsg)
- case typeClientKeyExchange:
- m = new(clientKeyExchangeMsg)
- case typeCertificateVerify:
- m = new(certificateVerifyMsg)
- case typeNextProtocol:
- m = new(nextProtoMsg)
- case typeFinished:
- m = new(finishedMsg)
- default:
- c.sendAlert(alertUnexpectedMessage)
- return nil, 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 !m.unmarshal(data) {
- c.sendAlert(alertUnexpectedMessage)
- return nil, alertUnexpectedMessage
- }
- return m, nil
- }
-
- // Write writes data to the connection.
- func (c *Conn) Write(b []byte) (int, error) {
- if err := c.error(); err != nil {
- return 0, err
- }
-
- if err := c.Handshake(); err != nil {
- return 0, c.setError(err)
- }
-
- c.out.Lock()
- defer c.out.Unlock()
-
- if !c.handshakeComplete {
- return 0, alertInternalError
- }
-
- // 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 {
- if _, ok := c.out.cipher.(cipher.BlockMode); ok {
- n, err := c.writeRecord(recordTypeApplicationData, b[:1])
- if err != nil {
- return n, c.setError(err)
- }
- m, b = 1, b[1:]
- }
- }
-
- n, err := c.writeRecord(recordTypeApplicationData, b)
- return n + m, c.setError(err)
- }
-
- // 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()
-
- for c.input == nil && c.error() == nil {
- if err := c.readRecord(recordTypeApplicationData); err != nil {
- // Soft error, like EAGAIN
- return 0, err
- }
- }
- if err := c.error(); err != nil {
- return 0, err
- }
- n, err = c.input.Read(b)
- if c.input.off >= len(c.input.data) {
- c.in.freeBlock(c.input)
- c.input = nil
- }
- return n, nil
- }
-
- // Close closes the connection.
- func (c *Conn) Close() error {
- var alertErr error
-
- c.handshakeMutex.Lock()
- defer c.handshakeMutex.Unlock()
- if c.handshakeComplete {
- alertErr = c.sendAlert(alertCloseNotify)
- }
-
- 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.error(); err != nil {
- return err
- }
- if c.handshakeComplete {
- return nil
- }
- if c.isClient {
- return c.clientHandshake()
- }
- return c.serverHandshake()
- }
-
- // 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.NegotiatedProtocol = c.clientProtocol
- state.DidResume = c.didResume
- state.NegotiatedProtocolIsMutual = !c.clientProtocolFallback
- state.CipherSuite = c.cipherSuite
- state.PeerCertificates = c.peerCertificates
- state.VerifiedChains = c.verifiedChains
- state.ServerName = c.serverName
- }
-
- 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("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)
- }
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