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// Copyright 2009 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 partially implements TLS 1.2, as specified in RFC 5246,
// and TLS 1.3, as specified in RFC 8446.
package tls
// BUG(agl): The crypto/tls package only implements some countermeasures
// against Lucky13 attacks on CBC-mode encryption, and only on SHA1
// variants. See http://www.isg.rhul.ac.uk/tls/TLStiming.pdf and
// https://www.imperialviolet.org/2013/02/04/luckythirteen.html.
import (
"crypto"
"crypto/ecdsa"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"net"
"strings"
"time"
)
// Server returns a new TLS server side connection
// using conn as the underlying transport.
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func Server(conn net.Conn, config *Config) *Conn {
return &Conn{conn: conn, config: config}
}
// Client returns a new TLS client side connection
// using conn as the underlying transport.
// The config cannot be nil: users must set either ServerName or
// InsecureSkipVerify in the config.
func Client(conn net.Conn, config *Config) *Conn {
return &Conn{conn: conn, config: config, isClient: true}
}
// A listener implements a network listener (net.Listener) for TLS connections.
type listener struct {
net.Listener
config *Config
}
// Accept waits for and returns the next incoming TLS connection.
// The returned connection is of type *Conn.
func (l *listener) Accept() (net.Conn, error) {
c, err := l.Listener.Accept()
if err != nil {
return nil, err
}
return Server(c, l.config), nil
}
// NewListener creates a Listener which accepts connections from an inner
// Listener and wraps each connection with Server.
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func NewListener(inner net.Listener, config *Config) net.Listener {
l := new(listener)
l.Listener = inner
l.config = config
return l
}
// Listen creates a TLS listener accepting connections on the
// given network address using net.Listen.
// The configuration config must be non-nil and must include
// at least one certificate or else set GetCertificate.
func Listen(network, laddr string, config *Config) (net.Listener, error) {
if config == nil || (len(config.Certificates) == 0 && config.GetCertificate == nil) {
return nil, errors.New("tls: neither Certificates nor GetCertificate set in Config")
}
l, err := net.Listen(network, laddr)
if err != nil {
return nil, err
}
return NewListener(l, config), nil
}
type timeoutError struct{}
func (timeoutError) Error() string { return "tls: DialWithDialer timed out" }
func (timeoutError) Timeout() bool { return true }
func (timeoutError) Temporary() bool { return true }
// DialWithDialer connects to the given network address using dialer.Dial and
// then initiates a TLS handshake, returning the resulting TLS connection. Any
// timeout or deadline given in the dialer apply to connection and TLS
// handshake as a whole.
//
// DialWithDialer interprets a nil configuration as equivalent to the zero
// configuration; see the documentation of Config for the defaults.
func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) {
// We want the Timeout and Deadline values from dialer to cover the
// whole process: TCP connection and TLS handshake. This means that we
// also need to start our own timers now.
timeout := dialer.Timeout
if !dialer.Deadline.IsZero() {
deadlineTimeout := time.Until(dialer.Deadline)
if timeout == 0 || deadlineTimeout < timeout {
timeout = deadlineTimeout
}
}
var errChannel chan error
if timeout != 0 {
errChannel = make(chan error, 2)
time.AfterFunc(timeout, func() {
errChannel <- timeoutError{}
})
}
rawConn, err := dialer.Dial(network, addr)
if err != nil {
return nil, err
}
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
hostname := addr[:colonPos]
if config == nil {
config = defaultConfig()
}
// If no ServerName is set, infer the ServerName
// from the hostname we're connecting to.
if config.ServerName == "" {
// Make a copy to avoid polluting argument or default.
c := config.Clone()
c.ServerName = hostname
config = c
}
conn := Client(rawConn, config)
if timeout == 0 {
err = conn.Handshake()
} else {
go func() {
errChannel <- conn.Handshake()
}()
err = <-errChannel
}
if err != nil {
rawConn.Close()
return nil, err
}
return conn, nil
}
// Dial connects to the given network address using net.Dial
// and then initiates a TLS handshake, returning the resulting
// TLS connection.
// Dial interprets a nil configuration as equivalent to
// the zero configuration; see the documentation of Config
// for the defaults.
func Dial(network, addr string, config *Config) (*Conn, error) {
return DialWithDialer(new(net.Dialer), network, addr, config)
}
// LoadX509KeyPair reads and parses a public/private key pair from a pair
// of files. The files must contain PEM encoded data. The certificate file
// may contain intermediate certificates following the leaf certificate to
// form a certificate chain. On successful return, Certificate.Leaf will
// be nil because the parsed form of the certificate is not retained.
func LoadX509KeyPair(certFile, keyFile string) (Certificate, error) {
certPEMBlock, err := ioutil.ReadFile(certFile)
if err != nil {
return Certificate{}, err
}
keyPEMBlock, err := ioutil.ReadFile(keyFile)
if err != nil {
return Certificate{}, err
}
return X509KeyPair(certPEMBlock, keyPEMBlock)
}
// X509KeyPair parses a public/private key pair from a pair of
// PEM encoded data. On successful return, Certificate.Leaf will be nil because
// the parsed form of the certificate is not retained.
func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error) {
fail := func(err error) (Certificate, error) { return Certificate{}, err }
var cert Certificate
var skippedBlockTypes []string
for {
var certDERBlock *pem.Block
certDERBlock, certPEMBlock = pem.Decode(certPEMBlock)
if certDERBlock == nil {
break
}
if certDERBlock.Type == "CERTIFICATE" {
cert.Certificate = append(cert.Certificate, certDERBlock.Bytes)
} else {
skippedBlockTypes = append(skippedBlockTypes, certDERBlock.Type)
}
}
if len(cert.Certificate) == 0 {
if len(skippedBlockTypes) == 0 {
return fail(errors.New("tls: failed to find any PEM data in certificate input"))
}
if len(skippedBlockTypes) == 1 && strings.HasSuffix(skippedBlockTypes[0], "PRIVATE KEY") {
return fail(errors.New("tls: failed to find certificate PEM data in certificate input, but did find a private key; PEM inputs may have been switched"))
}
return fail(fmt.Errorf("tls: failed to find \"CERTIFICATE\" PEM block in certificate input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
}
skippedBlockTypes = skippedBlockTypes[:0]
var keyDERBlock *pem.Block
for {
keyDERBlock, keyPEMBlock = pem.Decode(keyPEMBlock)
if keyDERBlock == nil {
if len(skippedBlockTypes) == 0 {
return fail(errors.New("tls: failed to find any PEM data in key input"))
}
if len(skippedBlockTypes) == 1 && skippedBlockTypes[0] == "CERTIFICATE" {
return fail(errors.New("tls: found a certificate rather than a key in the PEM for the private key"))
}
return fail(fmt.Errorf("tls: failed to find PEM block with type ending in \"PRIVATE KEY\" in key input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
}
if keyDERBlock.Type == "PRIVATE KEY" || strings.HasSuffix(keyDERBlock.Type, " PRIVATE KEY") {
break
}
skippedBlockTypes = append(skippedBlockTypes, keyDERBlock.Type)
}
// We don't need to parse the public key for TLS, but we so do anyway
// to check that it looks sane and matches the private key.
x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
if err != nil {
return fail(err)
}
cert.PrivateKey, err = parsePrivateKey(keyDERBlock.Bytes)
if err != nil {
return fail(err)
}
switch pub := x509Cert.PublicKey.(type) {
case *rsa.PublicKey:
priv, ok := cert.PrivateKey.(*rsa.PrivateKey)
if !ok {
return fail(errors.New("tls: private key type does not match public key type"))
}
if pub.N.Cmp(priv.N) != 0 {
return fail(errors.New("tls: private key does not match public key"))
}
case *ecdsa.PublicKey:
priv, ok := cert.PrivateKey.(*ecdsa.PrivateKey)
if !ok {
return fail(errors.New("tls: private key type does not match public key type"))
}
if pub.X.Cmp(priv.X) != 0 || pub.Y.Cmp(priv.Y) != 0 {
return fail(errors.New("tls: private key does not match public key"))
}
default:
return fail(errors.New("tls: unknown public key algorithm"))
}
return cert, nil
}
// Attempt to parse the given private key DER block. OpenSSL 0.9.8 generates
// PKCS#1 private keys by default, while OpenSSL 1.0.0 generates PKCS#8 keys.
// OpenSSL ecparam generates SEC1 EC private keys for ECDSA. We try all three.
func parsePrivateKey(der []byte) (crypto.PrivateKey, error) {
if key, err := x509.ParsePKCS1PrivateKey(der); err == nil {
return key, nil
}
if key, err := x509.ParsePKCS8PrivateKey(der); err == nil {
switch key := key.(type) {
case *rsa.PrivateKey, *ecdsa.PrivateKey:
return key, nil
default:
return nil, errors.New("tls: found unknown private key type in PKCS#8 wrapping")
}
}
if key, err := x509.ParseECPrivateKey(der); err == nil {
return key, nil
}
return nil, errors.New("tls: failed to parse private key")
}
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