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 RTC_BASE_OPENSSL_STREAM_ADAPTER_H_ 12 #define RTC_BASE_OPENSSL_STREAM_ADAPTER_H_ 13 14 #include <openssl/ossl_typ.h> 15 #include <stddef.h> 16 #include <stdint.h> 17 18 #include <memory> 19 #include <string> 20 #include <vector> 21 22 #include "rtc_base/buffer.h" 23 #include "rtc_base/openssl_identity.h" 24 #include "rtc_base/ssl_identity.h" 25 #include "rtc_base/ssl_stream_adapter.h" 26 #include "rtc_base/stream.h" 27 28 namespace rtc { 29 30 // This class was written with OpenSSLAdapter (a socket adapter) as a 31 // starting point. It has similar structure and functionality, but uses a 32 // "peer-to-peer" mode, verifying the peer's certificate using a digest 33 // sent over a secure signaling channel. 34 // 35 // Static methods to initialize and deinit the SSL library are in 36 // OpenSSLAdapter. These should probably be moved out to a neutral class. 37 // 38 // In a few cases I have factored out some OpenSSLAdapter code into static 39 // methods so it can be reused from this class. Eventually that code should 40 // probably be moved to a common support class. Unfortunately there remain a 41 // few duplicated sections of code. I have not done more restructuring because 42 // I did not want to affect existing code that uses OpenSSLAdapter. 43 // 44 // This class does not support the SSL connection restart feature present in 45 // OpenSSLAdapter. I am not entirely sure how the feature is useful and I am 46 // not convinced that it works properly. 47 // 48 // This implementation is careful to disallow data exchange after an SSL error, 49 // and it has an explicit SSL_CLOSED state. It should not be possible to send 50 // any data in clear after one of the StartSSL methods has been called. 51 52 // Look in sslstreamadapter.h for documentation of the methods. 53 54 class SSLCertChain; 55 56 /////////////////////////////////////////////////////////////////////////////// 57 58 class OpenSSLStreamAdapter final : public SSLStreamAdapter { 59 public: 60 explicit OpenSSLStreamAdapter(std::unique_ptr<StreamInterface> stream); 61 ~OpenSSLStreamAdapter() override; 62 63 void SetIdentity(std::unique_ptr<SSLIdentity> identity) override; 64 OpenSSLIdentity* GetIdentityForTesting() const override; 65 66 // Default argument is for compatibility 67 void SetServerRole(SSLRole role = SSL_SERVER) override; 68 bool SetPeerCertificateDigest( 69 const std::string& digest_alg, 70 const unsigned char* digest_val, 71 size_t digest_len, 72 SSLPeerCertificateDigestError* error = nullptr) override; 73 74 std::unique_ptr<SSLCertChain> GetPeerSSLCertChain() const override; 75 76 // Goes from state SSL_NONE to either SSL_CONNECTING or SSL_WAIT, depending 77 // on whether the underlying stream is already open or not. 78 int StartSSL() override; 79 void SetMode(SSLMode mode) override; 80 void SetMaxProtocolVersion(SSLProtocolVersion version) override; 81 void SetInitialRetransmissionTimeout(int timeout_ms) override; 82 83 StreamResult Read(void* data, 84 size_t data_len, 85 size_t* read, 86 int* error) override; 87 StreamResult Write(const void* data, 88 size_t data_len, 89 size_t* written, 90 int* error) override; 91 void Close() override; 92 StreamState GetState() const override; 93 94 // TODO(guoweis): Move this away from a static class method. 95 static std::string SslCipherSuiteToName(int crypto_suite); 96 97 bool GetSslCipherSuite(int* cipher) override; 98 99 SSLProtocolVersion GetSslVersion() const override; 100 bool GetSslVersionBytes(int* version) const override; 101 // Key Extractor interface 102 bool ExportKeyingMaterial(const std::string& label, 103 const uint8_t* context, 104 size_t context_len, 105 bool use_context, 106 uint8_t* result, 107 size_t result_len) override; 108 109 // DTLS-SRTP interface 110 bool SetDtlsSrtpCryptoSuites(const std::vector<int>& crypto_suites) override; 111 bool GetDtlsSrtpCryptoSuite(int* crypto_suite) override; 112 113 bool IsTlsConnected() override; 114 115 // Capabilities interfaces. 116 static bool IsBoringSsl(); 117 118 static bool IsAcceptableCipher(int cipher, KeyType key_type); 119 static bool IsAcceptableCipher(const std::string& cipher, KeyType key_type); 120 121 // Use our timeutils.h source of timing in BoringSSL, allowing us to test 122 // using a fake clock. 123 static void EnableTimeCallbackForTesting(); 124 125 protected: 126 void OnEvent(StreamInterface* stream, int events, int err) override; 127 128 private: 129 enum SSLState { 130 // Before calling one of the StartSSL methods, data flows 131 // in clear text. 132 SSL_NONE, 133 SSL_WAIT, // waiting for the stream to open to start SSL negotiation 134 SSL_CONNECTING, // SSL negotiation in progress 135 SSL_CONNECTED, // SSL stream successfully established 136 SSL_ERROR, // some SSL error occurred, stream is closed 137 SSL_CLOSED // Clean close 138 }; 139 140 enum { MSG_TIMEOUT = MSG_MAX + 1 }; 141 142 // The following three methods return 0 on success and a negative 143 // error code on failure. The error code may be from OpenSSL or -1 144 // on some other error cases, so it can't really be interpreted 145 // unfortunately. 146 147 // Prepare SSL library, state is SSL_CONNECTING. 148 int BeginSSL(); 149 // Perform SSL negotiation steps. 150 int ContinueSSL(); 151 152 // Error handler helper. signal is given as true for errors in 153 // asynchronous contexts (when an error method was not returned 154 // through some other method), and in that case an SE_CLOSE event is 155 // raised on the stream with the specified error. 156 // A 0 error means a graceful close, otherwise there is not really enough 157 // context to interpret the error code. 158 // |alert| indicates an alert description (one of the SSL_AD constants) to 159 // send to the remote endpoint when closing the association. If 0, a normal 160 // shutdown will be performed. 161 void Error(const char* context, int err, uint8_t alert, bool signal); 162 void Cleanup(uint8_t alert); 163 164 // Override MessageHandler 165 void OnMessage(Message* msg) override; 166 167 // Flush the input buffers by reading left bytes (for DTLS) 168 void FlushInput(unsigned int left); 169 170 // SSL library configuration 171 SSL_CTX* SetupSSLContext(); 172 // Verify the peer certificate matches the signaled digest. 173 bool VerifyPeerCertificate(); 174 // SSL certificate verification callback. See 175 // SSL_CTX_set_cert_verify_callback. 176 static int SSLVerifyCallback(X509_STORE_CTX* store, void* arg); 177 WaitingToVerifyPeerCertificate()178 bool WaitingToVerifyPeerCertificate() const { 179 return GetClientAuthEnabled() && !peer_certificate_verified_; 180 } 181 HasPeerCertificateDigest()182 bool HasPeerCertificateDigest() const { 183 return !peer_certificate_digest_algorithm_.empty() && 184 !peer_certificate_digest_value_.empty(); 185 } 186 187 SSLState state_; 188 SSLRole role_; 189 int ssl_error_code_; // valid when state_ == SSL_ERROR or SSL_CLOSED 190 // Whether the SSL negotiation is blocked on needing to read or 191 // write to the wrapped stream. 192 bool ssl_read_needs_write_; 193 bool ssl_write_needs_read_; 194 195 SSL* ssl_; 196 SSL_CTX* ssl_ctx_; 197 198 // Our key and certificate. 199 std::unique_ptr<OpenSSLIdentity> identity_; 200 // The certificate chain that the peer presented. Initially null, until the 201 // connection is established. 202 std::unique_ptr<SSLCertChain> peer_cert_chain_; 203 bool peer_certificate_verified_ = false; 204 // The digest of the certificate that the peer must present. 205 Buffer peer_certificate_digest_value_; 206 std::string peer_certificate_digest_algorithm_; 207 208 // The DtlsSrtp ciphers 209 std::string srtp_ciphers_; 210 211 // Do DTLS or not 212 SSLMode ssl_mode_; 213 214 // Max. allowed protocol version 215 SSLProtocolVersion ssl_max_version_; 216 217 // A 50-ms initial timeout ensures rapid setup on fast connections, but may 218 // be too aggressive for low bandwidth links. 219 int dtls_handshake_timeout_ms_ = 50; 220 221 // TODO(https://bugs.webrtc.org/10261): Completely remove this option in M84. 222 const bool support_legacy_tls_protocols_flag_; 223 }; 224 225 ///////////////////////////////////////////////////////////////////////////// 226 227 } // namespace rtc 228 229 #endif // RTC_BASE_OPENSSL_STREAM_ADAPTER_H_ 230