1/*
2 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#ifndef WEBRTC_BASE_SSLSTREAMADAPTER_H_
12#define WEBRTC_BASE_SSLSTREAMADAPTER_H_
13
14#include <string>
15#include <vector>
16
17#include "webrtc/base/stream.h"
18#include "webrtc/base/sslidentity.h"
19
20namespace rtc {
21
22// SSLStreamAdapter : A StreamInterfaceAdapter that does SSL/TLS.
23// After SSL has been started, the stream will only open on successful
24// SSL verification of certificates, and the communication is
25// encrypted of course.
26//
27// This class was written with SSLAdapter as a starting point. It
28// offers a similar interface, with two differences: there is no
29// support for a restartable SSL connection, and this class has a
30// peer-to-peer mode.
31//
32// The SSL library requires initialization and cleanup. Static method
33// for doing this are in SSLAdapter. They should possibly be moved out
34// to a neutral class.
35
36
37enum SSLRole { SSL_CLIENT, SSL_SERVER };
38enum SSLMode { SSL_MODE_TLS, SSL_MODE_DTLS };
39
40// Errors for Read -- in the high range so no conflict with OpenSSL.
41enum { SSE_MSG_TRUNC = 0xff0001 };
42
43class SSLStreamAdapter : public StreamAdapterInterface {
44 public:
45  // Instantiate an SSLStreamAdapter wrapping the given stream,
46  // (using the selected implementation for the platform).
47  // Caller is responsible for freeing the returned object.
48  static SSLStreamAdapter* Create(StreamInterface* stream);
49
50  explicit SSLStreamAdapter(StreamInterface* stream)
51      : StreamAdapterInterface(stream), ignore_bad_cert_(false),
52        client_auth_enabled_(true) { }
53
54  void set_ignore_bad_cert(bool ignore) { ignore_bad_cert_ = ignore; }
55  bool ignore_bad_cert() const { return ignore_bad_cert_; }
56
57  void set_client_auth_enabled(bool enabled) { client_auth_enabled_ = enabled; }
58  bool client_auth_enabled() const { return client_auth_enabled_; }
59
60  // Specify our SSL identity: key and certificate. Mostly this is
61  // only used in the peer-to-peer mode (unless we actually want to
62  // provide a client certificate to a server).
63  // SSLStream takes ownership of the SSLIdentity object and will
64  // free it when appropriate. Should be called no more than once on a
65  // given SSLStream instance.
66  virtual void SetIdentity(SSLIdentity* identity) = 0;
67
68  // Call this to indicate that we are to play the server's role in
69  // the peer-to-peer mode.
70  // The default argument is for backward compatibility
71  // TODO(ekr@rtfm.com): rename this SetRole to reflect its new function
72  virtual void SetServerRole(SSLRole role = SSL_SERVER) = 0;
73
74  // Do DTLS or TLS
75  virtual void SetMode(SSLMode mode) = 0;
76
77  // The mode of operation is selected by calling either
78  // StartSSLWithServer or StartSSLWithPeer.
79  // Use of the stream prior to calling either of these functions will
80  // pass data in clear text.
81  // Calling one of these functions causes SSL negotiation to begin as
82  // soon as possible: right away if the underlying wrapped stream is
83  // already opened, or else as soon as it opens.
84  //
85  // These functions return a negative error code on failure.
86  // Returning 0 means success so far, but negotiation is probably not
87  // complete and will continue asynchronously.  In that case, the
88  // exposed stream will open after successful negotiation and
89  // verification, or an SE_CLOSE event will be raised if negotiation
90  // fails.
91
92  // StartSSLWithServer starts SSL negotiation with a server in
93  // traditional mode. server_name specifies the expected server name
94  // which the server's certificate needs to specify.
95  virtual int StartSSLWithServer(const char* server_name) = 0;
96
97  // StartSSLWithPeer starts negotiation in the special peer-to-peer
98  // mode.
99  // Generally, SetIdentity() and possibly SetServerRole() should have
100  // been called before this.
101  // SetPeerCertificate() or SetPeerCertificateDigest() must also be called.
102  // It may be called after StartSSLWithPeer() but must be called before the
103  // underlying stream opens.
104  virtual int StartSSLWithPeer() = 0;
105
106  // Specify the digest of the certificate that our peer is expected to use in
107  // peer-to-peer mode. Only this certificate will be accepted during
108  // SSL verification. The certificate is assumed to have been
109  // obtained through some other secure channel (such as the XMPP
110  // channel). Unlike SetPeerCertificate(), this must specify the
111  // terminal certificate, not just a CA.
112  // SSLStream makes a copy of the digest value.
113  virtual bool SetPeerCertificateDigest(const std::string& digest_alg,
114                                        const unsigned char* digest_val,
115                                        size_t digest_len) = 0;
116
117  // Retrieves the peer's X.509 certificate, if a connection has been
118  // established. It returns the transmitted over SSL, including the entire
119  // chain. The returned certificate is owned by the caller.
120  virtual bool GetPeerCertificate(SSLCertificate** cert) const = 0;
121
122  // Key Exporter interface from RFC 5705
123  // Arguments are:
124  // label               -- the exporter label.
125  //                        part of the RFC defining each exporter
126  //                        usage (IN)
127  // context/context_len -- a context to bind to for this connection;
128  //                        optional, can be NULL, 0 (IN)
129  // use_context         -- whether to use the context value
130  //                        (needed to distinguish no context from
131  //                        zero-length ones).
132  // result              -- where to put the computed value
133  // result_len          -- the length of the computed value
134  virtual bool ExportKeyingMaterial(const std::string& label,
135                                    const uint8* context,
136                                    size_t context_len,
137                                    bool use_context,
138                                    uint8* result,
139                                    size_t result_len) {
140    return false;  // Default is unsupported
141  }
142
143
144  // DTLS-SRTP interface
145  virtual bool SetDtlsSrtpCiphers(const std::vector<std::string>& ciphers) {
146    return false;
147  }
148
149  virtual bool GetDtlsSrtpCipher(std::string* cipher) {
150    return false;
151  }
152
153  // Capabilities testing
154  static bool HaveDtls();
155  static bool HaveDtlsSrtp();
156  static bool HaveExporter();
157
158 private:
159  // If true, the server certificate need not match the configured
160  // server_name, and in fact missing certificate authority and other
161  // verification errors are ignored.
162  bool ignore_bad_cert_;
163
164  // If true (default), the client is required to provide a certificate during
165  // handshake. If no certificate is given, handshake fails. This applies to
166  // server mode only.
167  bool client_auth_enabled_;
168};
169
170}  // namespace rtc
171
172#endif  // WEBRTC_BASE_SSLSTREAMADAPTER_H_
173