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 ssl_cipher_st SSL_CIPHER; 24 typedef struct x509_store_ctx_st X509_STORE_CTX; 25 26 namespace rtc { 27 28 // This class was written with OpenSSLAdapter (a socket adapter) as a 29 // starting point. It has similar structure and functionality, with 30 // the peer-to-peer mode added. 31 // 32 // Static methods to initialize and deinit the SSL library are in 33 // OpenSSLAdapter. This class also uses 34 // OpenSSLAdapter::custom_verify_callback_ (a static field). These 35 // should probably be moved out to a neutral class. 36 // 37 // In a few cases I have factored out some OpenSSLAdapter code into 38 // static methods so it can be reused from this class. Eventually that 39 // code should probably be moved to a common support 40 // class. Unfortunately there remain a few duplicated sections of 41 // code. I have not done more restructuring because I did not want to 42 // affect existing code that uses OpenSSLAdapter. 43 // 44 // This class does not support the SSL connection restart feature 45 // present in OpenSSLAdapter. I am not entirely sure how the feature 46 // is useful and I am not convinced that it works properly. 47 // 48 // This implementation is careful to disallow data exchange after an 49 // SSL error, and it has an explicit SSL_CLOSED state. It should not 50 // be possible to send any data in clear after one of the StartSSL 51 // methods has been called. 52 53 // Look in sslstreamadapter.h for documentation of the methods. 54 55 class OpenSSLIdentity; 56 57 /////////////////////////////////////////////////////////////////////////////// 58 59 class OpenSSLStreamAdapter : public SSLStreamAdapter { 60 public: 61 explicit OpenSSLStreamAdapter(StreamInterface* stream); 62 ~OpenSSLStreamAdapter() override; 63 64 void SetIdentity(SSLIdentity* identity) override; 65 66 // Default argument is for compatibility 67 void SetServerRole(SSLRole role = SSL_SERVER) override; 68 bool SetPeerCertificateDigest(const std::string& digest_alg, 69 const unsigned char* digest_val, 70 size_t digest_len) override; 71 72 bool GetPeerCertificate(SSLCertificate** cert) const override; 73 74 int StartSSLWithServer(const char* server_name) override; 75 int StartSSLWithPeer() override; 76 void SetMode(SSLMode mode) override; 77 void SetMaxProtocolVersion(SSLProtocolVersion version) override; 78 79 StreamResult Read(void* data, 80 size_t data_len, 81 size_t* read, 82 int* error) override; 83 StreamResult Write(const void* data, 84 size_t data_len, 85 size_t* written, 86 int* error) override; 87 void Close() override; 88 StreamState GetState() const override; 89 90 // TODO(guoweis): Move this away from a static class method. 91 static std::string SslCipherSuiteToName(int crypto_suite); 92 93 bool GetSslCipherSuite(int* cipher) override; 94 95 // Key Extractor interface 96 bool ExportKeyingMaterial(const std::string& label, 97 const uint8_t* context, 98 size_t context_len, 99 bool use_context, 100 uint8_t* result, 101 size_t result_len) override; 102 103 // DTLS-SRTP interface 104 bool SetDtlsSrtpCryptoSuites(const std::vector<int>& crypto_suites) override; 105 bool GetDtlsSrtpCryptoSuite(int* crypto_suite) override; 106 107 // Capabilities interfaces 108 static bool HaveDtls(); 109 static bool HaveDtlsSrtp(); 110 static bool HaveExporter(); 111 112 // TODO(guoweis): Move this away from a static class method. 113 static int GetDefaultSslCipherForTest(SSLProtocolVersion version, 114 KeyType key_type); 115 116 protected: 117 void OnEvent(StreamInterface* stream, int events, int err) override; 118 119 private: 120 enum SSLState { 121 // Before calling one of the StartSSL methods, data flows 122 // in clear text. 123 SSL_NONE, 124 SSL_WAIT, // waiting for the stream to open to start SSL negotiation 125 SSL_CONNECTING, // SSL negotiation in progress 126 SSL_CONNECTED, // SSL stream successfully established 127 SSL_ERROR, // some SSL error occurred, stream is closed 128 SSL_CLOSED // Clean close 129 }; 130 131 enum { MSG_TIMEOUT = MSG_MAX+1}; 132 133 // The following three methods return 0 on success and a negative 134 // error code on failure. The error code may be from OpenSSL or -1 135 // on some other error cases, so it can't really be interpreted 136 // unfortunately. 137 138 // Go from state SSL_NONE to either SSL_CONNECTING or SSL_WAIT, 139 // depending on whether the underlying stream is already open or 140 // not. 141 int StartSSL(); 142 // Prepare SSL library, state is SSL_CONNECTING. 143 int BeginSSL(); 144 // Perform SSL negotiation steps. 145 int ContinueSSL(); 146 147 // Error handler helper. signal is given as true for errors in 148 // asynchronous contexts (when an error method was not returned 149 // through some other method), and in that case an SE_CLOSE event is 150 // raised on the stream with the specified error. 151 // A 0 error means a graceful close, otherwise there is not really enough 152 // context to interpret the error code. 153 void Error(const char* context, int err, bool signal); 154 void Cleanup(); 155 156 // Override MessageHandler 157 void OnMessage(Message* msg) override; 158 159 // Flush the input buffers by reading left bytes (for DTLS) 160 void FlushInput(unsigned int left); 161 162 // SSL library configuration 163 SSL_CTX* SetupSSLContext(); 164 // SSL verification check 165 bool SSLPostConnectionCheck(SSL* ssl, const char* server_name, 166 const X509* peer_cert, 167 const std::string& peer_digest); 168 // SSL certification verification error handler, called back from 169 // the openssl library. Returns an int interpreted as a boolean in 170 // the C style: zero means verification failure, non-zero means 171 // passed. 172 static int SSLVerifyCallback(int ok, X509_STORE_CTX* store); 173 174 SSLState state_; 175 SSLRole role_; 176 int ssl_error_code_; // valid when state_ == SSL_ERROR or SSL_CLOSED 177 // Whether the SSL negotiation is blocked on needing to read or 178 // write to the wrapped stream. 179 bool ssl_read_needs_write_; 180 bool ssl_write_needs_read_; 181 182 SSL* ssl_; 183 SSL_CTX* ssl_ctx_; 184 185 // Our key and certificate, mostly useful in peer-to-peer mode. 186 scoped_ptr<OpenSSLIdentity> identity_; 187 // in traditional mode, the server name that the server's certificate 188 // must specify. Empty in peer-to-peer mode. 189 std::string ssl_server_name_; 190 // The certificate that the peer must present or did present. Initially 191 // null in traditional mode, until the connection is established. 192 scoped_ptr<OpenSSLCertificate> peer_certificate_; 193 // In peer-to-peer mode, the digest of the certificate that 194 // the peer must present. 195 Buffer peer_certificate_digest_value_; 196 std::string peer_certificate_digest_algorithm_; 197 198 // OpenSSLAdapter::custom_verify_callback_ result 199 bool custom_verification_succeeded_; 200 201 // The DtlsSrtp ciphers 202 std::string srtp_ciphers_; 203 204 // Do DTLS or not 205 SSLMode ssl_mode_; 206 207 // Max. allowed protocol version 208 SSLProtocolVersion ssl_max_version_; 209 }; 210 211 ///////////////////////////////////////////////////////////////////////////// 212 213 } // namespace rtc 214 215 #endif // WEBRTC_BASE_OPENSSLSTREAMADAPTER_H__ 216
