[#1722] use sfl::CryptoSuites to init crypto context

sflphone-common/src/audio/audiortp/AudioSrtpSession.cpp

@@ -45,6 +45,8 @@ namespace sfl
 
 AudioSrtpSession::AudioSrtpSession (ManagerImpl * manager, SIPCall * sipcall) :
         ost::SymmetricRTPSession (ost::InetHostAddress (sipcall->getLocalIp().c_str()), sipcall->getLocalAudioPort()),
+	_localCryptoSuite(0),
+	_remoteCryptoSuite(0),
         AudioRtpSession<AudioSrtpSession> (manager, sipcall)
 {
 
@@ -68,7 +70,7 @@ std::string AudioSrtpSession::getLocalCryptoInfo() {
     // cryptographic context tagged 1, 2, 3...
     std::string tag = "1";
 
-    std::string crypto_suite = "AES_CM_128_HMAC_SHA1_32";
+    std::string crypto_suite = sfl::CryptoSuites[_localCryptoSuite].name;
 
     // srtp keys formated as the following  as the following
     // inline:NzB4d1BINUAvLEw6UzF3WSJ+PSdFcGdUJShpX1Zj|2^20|1:32
@@ -104,7 +106,7 @@ void AudioSrtpSession::initializeLocalMasterKey(void)
 {
 
     // @TODO key may have different length depending on cipher suite
-    _localMasterKeyLength = 16;
+    _localMasterKeyLength = sfl::CryptoSuites[_localCryptoSuite].masterKeyLength / 8;
 
     // Allocate memory for key
     unsigned char *random_key = new unsigned char[_localMasterKeyLength];
@@ -130,7 +132,7 @@ void AudioSrtpSession::initializeLocalMasterSalt(void)
 {
 
     // @TODO key may have different length depending on cipher suite 
-    _localMasterSaltLength = 14;
+  _localMasterSaltLength = sfl::CryptoSuites[_localCryptoSuite].masterSaltLength / 8;
 
     // Allocate memory for key
     unsigned char *random_key = new unsigned char[_localMasterSaltLength];
@@ -174,8 +176,9 @@ std::string AudioSrtpSession::getBase64ConcatenatedKeys()
 void AudioSrtpSession::unBase64ConcatenatedKeys(std::string base64keys)
 {
 
-    _remoteMasterKeyLength = 16;
-    _remoteMasterSaltLength = 14;
+    
+    _remoteMasterKeyLength = sfl::CryptoSuites[1].masterKeyLength / 8;
+    _remoteMasterSaltLength = sfl::CryptoSuites[1].masterSaltLength / 8;
 
     // length of decoded data data
     int length;
@@ -203,9 +206,9 @@ void AudioSrtpSession::initializeRemoteCryptoContext(void)
 					     SrtpEncryptionAESCM,         // encryption algo
 					     SrtpAuthenticationSha1Hmac,  // authtication algo
 					     _remoteMasterKey,            // Master Key
-					     128 / 8,                     // Master Key length
+					     _remoteMasterKeyLength,      // Master Key length
 					     _remoteMasterSalt,           // Master Salt
-					     112 / 8,                     // Master Salt length
+					     _remoteMasterSaltLength,     // Master Salt length
 					     128 / 8,                     // encryption keyl
 					     160 / 8,                     // authentication key len
 					     112 / 8,                     // session salt len
@@ -223,9 +226,9 @@ void AudioSrtpSession::initializeLocalCryptoContext(void)
 					      SrtpEncryptionAESCM,         // encryption algo
 					      SrtpAuthenticationSha1Hmac,  // authtication algo
 					      _localMasterKey,             // Master Key
-					      128 / 8,                     // Master Key length
+					      _localMasterKeyLength,       // Master Key length
 					      _localMasterSalt,            // Master Salt
-					      112 / 8,                     // Master Salt length
+					      _localMasterSaltLength,      // Master Salt length
 					      128 / 8,                     // encryption keyl
 					      160 / 8,                     // authentication key len
 					      112 / 8,                     // session salt len

sflphone-common/src/audio/audiortp/AudioSrtpSession.h

@@ -28,6 +28,30 @@ class SdesNegotiator;
 class ManagerImpl;
 class SIPCall;
 
+/* 
+   Table from RFC 4568 6.2. Crypto-Suites, which define key parameters for supported 
+   cipher suite
+
+   +---------------------+-------------+--------------+---------------+
+   |                     |AES_CM_128_  | AES_CM_128_  | F8_128_       |
+   |                     |HMAC_SHA1_80 | HMAC_SHA1_32 |  HMAC_SHA1_80 |
+   +---------------------+-------------+--------------+---------------+
+   | Master key length   |   128 bits  |   128 bits   |   128 bits    |
+   | Master salt length  |   112 bits  |   112 bits   |   112 bits    |
+   | SRTP lifetime       | 2^48 packets| 2^48 packets | 2^48 packets  |
+   | SRTCP lifetime      | 2^31 packets| 2^31 packets | 2^31 packets  |
+   | Cipher              | AES Counter | AES Counter  | AES F8 Mode   |
+   |                     | Mode        | Mode         |               |
+   | Encryption key      |   128 bits  |   128 bits   |   128 bits    |
+   | MAC                 |  HMAC-SHA1  |  HMAC-SHA1   |  HMAC-SHA1    |
+   | SRTP auth. tag      |    80 bits  |    32 bits   |    80 bits    |
+   | SRTCP auth. tag     |    80 bits  |    80 bits   |    80 bits    |
+   | SRTP auth. key len. |   160 bits  |   160 bits   |   160 bits    |
+   | SRTCP auth. key len.|   160 bits  |   160 bits   |   160 bits    |
+   +---------------------+-------------+--------------+---------------+
+*/
+
+
 namespace sfl {
 
     class SrtpException: public std::exception
@@ -66,20 +90,30 @@ namespace sfl {
 
 	    char* decodeBase64(unsigned char *input, int length, int *length_out);
 
+	    /** Default local crypto suite is AES_CM_128_HMAC_SHA1_80*/
+	    int _localCryptoSuite;
+
+	    /** Remote crypto suite is initialized at AES_CM_128_HMAC_SHA1_80*/
+	    int _remoteCryptoSuite;
+
             uint8 _localMasterKey[16];
 
+	    /** local master key length in byte */
 	    int _localMasterKeyLength;
 
 	    uint8 _localMasterSalt[14];
 
+	    /** local master salt length in byte */
 	    int _localMasterSaltLength;
 
 	    uint8 _remoteMasterKey[16];
 
+	    /** remote master key length in byte */
 	    int _remoteMasterKeyLength;
 
 	    uint8 _remoteMasterSalt[14];
 
+	    /** remote master salt length in byte */
 	    int _remoteMasterSaltLength;
 
 	    ost::CryptoContext* _remoteCryptoCtx;