henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 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_OPENSSLSTREAMADAPTER_H__ |
| 12 | #define WEBRTC_BASE_OPENSSLSTREAMADAPTER_H__ |
| 13 | |
| 14 | #include <string> |
| 15 | #include <vector> |
| 16 | |
| 17 | #include "webrtc/base/buffer.h" |
| 18 | #include "webrtc/base/sslstreamadapter.h" |
| 19 | #include "webrtc/base/opensslidentity.h" |
| 20 | |
| 21 | typedef struct ssl_st SSL; |
| 22 | typedef struct ssl_ctx_st SSL_CTX; |
| 23 | typedef struct x509_store_ctx_st X509_STORE_CTX; |
| 24 | |
| 25 | namespace rtc { |
| 26 | |
| 27 | // This class was written with OpenSSLAdapter (a socket adapter) as a |
| 28 | // starting point. It has similar structure and functionality, with |
| 29 | // the peer-to-peer mode added. |
| 30 | // |
| 31 | // Static methods to initialize and deinit the SSL library are in |
| 32 | // OpenSSLAdapter. This class also uses |
| 33 | // OpenSSLAdapter::custom_verify_callback_ (a static field). These |
| 34 | // should probably be moved out to a neutral class. |
| 35 | // |
| 36 | // In a few cases I have factored out some OpenSSLAdapter code into |
| 37 | // static methods so it can be reused from this class. Eventually that |
| 38 | // code should probably be moved to a common support |
| 39 | // class. Unfortunately there remain a few duplicated sections of |
| 40 | // code. I have not done more restructuring because I did not want to |
| 41 | // affect existing code that uses OpenSSLAdapter. |
| 42 | // |
| 43 | // This class does not support the SSL connection restart feature |
| 44 | // present in OpenSSLAdapter. I am not entirely sure how the feature |
| 45 | // is useful and I am not convinced that it works properly. |
| 46 | // |
| 47 | // This implementation is careful to disallow data exchange after an |
| 48 | // SSL error, and it has an explicit SSL_CLOSED state. It should not |
| 49 | // be possible to send any data in clear after one of the StartSSL |
| 50 | // methods has been called. |
| 51 | |
| 52 | // Look in sslstreamadapter.h for documentation of the methods. |
| 53 | |
| 54 | class OpenSSLIdentity; |
| 55 | |
| 56 | /////////////////////////////////////////////////////////////////////////////// |
| 57 | |
| 58 | class OpenSSLStreamAdapter : public SSLStreamAdapter { |
| 59 | public: |
| 60 | explicit OpenSSLStreamAdapter(StreamInterface* stream); |
| 61 | virtual ~OpenSSLStreamAdapter(); |
| 62 | |
| 63 | virtual void SetIdentity(SSLIdentity* identity); |
| 64 | |
| 65 | // Default argument is for compatibility |
| 66 | virtual void SetServerRole(SSLRole role = SSL_SERVER); |
| 67 | virtual bool SetPeerCertificateDigest(const std::string& digest_alg, |
| 68 | const unsigned char* digest_val, |
| 69 | size_t digest_len); |
| 70 | |
| 71 | virtual bool GetPeerCertificate(SSLCertificate** cert) const; |
| 72 | |
| 73 | virtual int StartSSLWithServer(const char* server_name); |
| 74 | virtual int StartSSLWithPeer(); |
| 75 | virtual void SetMode(SSLMode mode); |
| 76 | |
| 77 | virtual StreamResult Read(void* data, size_t data_len, |
| 78 | size_t* read, int* error); |
| 79 | virtual StreamResult Write(const void* data, size_t data_len, |
| 80 | size_t* written, int* error); |
| 81 | virtual void Close(); |
| 82 | virtual StreamState GetState() const; |
| 83 | |
| 84 | // Key Extractor interface |
| 85 | virtual bool ExportKeyingMaterial(const std::string& label, |
| 86 | const uint8* context, |
| 87 | size_t context_len, |
| 88 | bool use_context, |
| 89 | uint8* result, |
| 90 | size_t result_len); |
| 91 | |
| 92 | |
| 93 | // DTLS-SRTP interface |
| 94 | virtual bool SetDtlsSrtpCiphers(const std::vector<std::string>& ciphers); |
| 95 | virtual bool GetDtlsSrtpCipher(std::string* cipher); |
| 96 | |
| 97 | // Capabilities interfaces |
| 98 | static bool HaveDtls(); |
| 99 | static bool HaveDtlsSrtp(); |
| 100 | static bool HaveExporter(); |
| 101 | |
| 102 | protected: |
| 103 | virtual void OnEvent(StreamInterface* stream, int events, int err); |
| 104 | |
| 105 | private: |
| 106 | enum SSLState { |
| 107 | // Before calling one of the StartSSL methods, data flows |
| 108 | // in clear text. |
| 109 | SSL_NONE, |
| 110 | SSL_WAIT, // waiting for the stream to open to start SSL negotiation |
| 111 | SSL_CONNECTING, // SSL negotiation in progress |
| 112 | SSL_CONNECTED, // SSL stream successfully established |
| 113 | SSL_ERROR, // some SSL error occurred, stream is closed |
| 114 | SSL_CLOSED // Clean close |
| 115 | }; |
| 116 | |
| 117 | enum { MSG_TIMEOUT = MSG_MAX+1}; |
| 118 | |
| 119 | // The following three methods return 0 on success and a negative |
| 120 | // error code on failure. The error code may be from OpenSSL or -1 |
| 121 | // on some other error cases, so it can't really be interpreted |
| 122 | // unfortunately. |
| 123 | |
| 124 | // Go from state SSL_NONE to either SSL_CONNECTING or SSL_WAIT, |
| 125 | // depending on whether the underlying stream is already open or |
| 126 | // not. |
| 127 | int StartSSL(); |
| 128 | // Prepare SSL library, state is SSL_CONNECTING. |
| 129 | int BeginSSL(); |
| 130 | // Perform SSL negotiation steps. |
| 131 | int ContinueSSL(); |
| 132 | |
| 133 | // Error handler helper. signal is given as true for errors in |
| 134 | // asynchronous contexts (when an error method was not returned |
| 135 | // through some other method), and in that case an SE_CLOSE event is |
| 136 | // raised on the stream with the specified error. |
| 137 | // A 0 error means a graceful close, otherwise there is not really enough |
| 138 | // context to interpret the error code. |
| 139 | void Error(const char* context, int err, bool signal); |
| 140 | void Cleanup(); |
| 141 | |
| 142 | // Override MessageHandler |
| 143 | virtual void OnMessage(Message* msg); |
| 144 | |
| 145 | // Flush the input buffers by reading left bytes (for DTLS) |
| 146 | void FlushInput(unsigned int left); |
| 147 | |
| 148 | // SSL library configuration |
| 149 | SSL_CTX* SetupSSLContext(); |
| 150 | // SSL verification check |
| 151 | bool SSLPostConnectionCheck(SSL* ssl, const char* server_name, |
| 152 | const X509* peer_cert, |
| 153 | const std::string& peer_digest); |
| 154 | // SSL certification verification error handler, called back from |
| 155 | // the openssl library. Returns an int interpreted as a boolean in |
| 156 | // the C style: zero means verification failure, non-zero means |
| 157 | // passed. |
| 158 | static int SSLVerifyCallback(int ok, X509_STORE_CTX* store); |
| 159 | |
| 160 | SSLState state_; |
| 161 | SSLRole role_; |
| 162 | int ssl_error_code_; // valid when state_ == SSL_ERROR or SSL_CLOSED |
| 163 | // Whether the SSL negotiation is blocked on needing to read or |
| 164 | // write to the wrapped stream. |
| 165 | bool ssl_read_needs_write_; |
| 166 | bool ssl_write_needs_read_; |
| 167 | |
| 168 | SSL* ssl_; |
| 169 | SSL_CTX* ssl_ctx_; |
| 170 | |
| 171 | // Our key and certificate, mostly useful in peer-to-peer mode. |
| 172 | scoped_ptr<OpenSSLIdentity> identity_; |
| 173 | // in traditional mode, the server name that the server's certificate |
| 174 | // must specify. Empty in peer-to-peer mode. |
| 175 | std::string ssl_server_name_; |
| 176 | // The certificate that the peer must present or did present. Initially |
| 177 | // null in traditional mode, until the connection is established. |
| 178 | scoped_ptr<OpenSSLCertificate> peer_certificate_; |
| 179 | // In peer-to-peer mode, the digest of the certificate that |
| 180 | // the peer must present. |
| 181 | Buffer peer_certificate_digest_value_; |
| 182 | std::string peer_certificate_digest_algorithm_; |
| 183 | |
| 184 | // OpenSSLAdapter::custom_verify_callback_ result |
| 185 | bool custom_verification_succeeded_; |
| 186 | |
| 187 | // The DtlsSrtp ciphers |
| 188 | std::string srtp_ciphers_; |
| 189 | |
| 190 | // Do DTLS or not |
| 191 | SSLMode ssl_mode_; |
| 192 | }; |
| 193 | |
| 194 | ///////////////////////////////////////////////////////////////////////////// |
| 195 | |
| 196 | } // namespace rtc |
| 197 | |
| 198 | #endif // WEBRTC_BASE_OPENSSLSTREAMADAPTER_H__ |