support mki value
Add support mki value in the DTLS-SRTP
Signed-off-by: Johan Pascal <johan.pascal@belledonne-communications.com>
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 68afcba..f5229ef 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -782,7 +782,7 @@
{
mbedtls_ssl_srtp_profile client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
size_t i,j;
- uint16_t profile_length;
+ size_t profile_length;
/* If use_srtp is not configured, just ignore the extension */
if( ( ssl->conf->dtls_srtp_profile_list == NULL ) || ( ssl->conf->dtls_srtp_profile_list_len == 0 ) )
@@ -798,53 +798,71 @@
* SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>;
*
- * Note: srtp_mki is not supported
*/
/* Min length is 5 : at least one protection profile(2 bytes) and length(2 bytes) + srtp_mki length(1 byte) */
if( len < 5 )
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
- /*
- * Use our order of preference
- */
- profile_length = buf[0]<<8|buf[1]; /* first 2 bytes are protection profile length(in bytes) */
- for( i=0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
+ ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_SRTP_UNSET_PROFILE;
+
+ profile_length = ( buf[0]<<8 ) | buf[1]; /* first 2 bytes are protection profile length(in bytes) */
+
+
+ /* parse the extension list values are defined in http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml */
+ for( j=0; j < profile_length; j+=2 )
{
- /* parse the extension list values are defined in http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml */
- for (j=0; j<profile_length; j+=2) { /* parse only the protection profile, srtp_mki is not supported and ignored */
- uint16_t protection_profile_value = buf[j+2]<<8 | buf[j+3]; /* +2 to skip the length field */
+ uint16_t protection_profile_value = buf[j+2]<<8 | buf[j+3]; /* +2 to skip the length field */
- switch ( protection_profile_value ) {
- case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE:
- client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80;
- break;
- case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE:
- client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32;
- break;
- case MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE:
- client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_80;
- break;
- case MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE:
- client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_32;
- break;
- default:
- client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
- break;
- }
-
- if (client_protection == ssl->conf->dtls_srtp_profile_list[i]) {
+ switch ( protection_profile_value )
+ {
+ case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE:
+ client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80;
+ break;
+ case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE:
+ client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32;
+ break;
+ case MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE:
+ client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_80;
+ break;
+ case MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE:
+ client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_32;
+ break;
+ default:
+ client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
+ break;
+ }
+ /* check if suggested profile is in our list */
+ for( i=0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
+ {
+ if( client_protection == ssl->conf->dtls_srtp_profile_list[i] )
+ {
ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
- return 0;
+ break;
}
}
+ if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_SRTP_UNSET_PROFILE )
+ break;
+ }
+ if( ( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED ) &&
+ ( len > ( profile_length + 2 ) ) )
+ {
+ ssl->dtls_srtp_info.mki_len = buf[ profile_length + 2 ];
+ if( ssl->dtls_srtp_info.mki_len > MBEDTLS_DTLS_SRTP_MAX_MKI_LENGTH )
+ {
+ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
+ ssl->dtls_srtp_info.mki_len = 0;
+ return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+ }
+
+ for( i=0; i < ssl->dtls_srtp_info.mki_len; i++ )
+ {
+ ssl->dtls_srtp_info.mki_value[i] = buf[ profile_length + 2 + i ];
+ }
}
- /* If we get there, no match was found */
- ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_SRTP_UNSET_PROFILE;
- // mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
- // MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
- return( 0 );
+ return( 0 );
}
#endif /* MBEDTLS_SSL_DTLS_SRTP */
@@ -2585,6 +2603,8 @@
static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
+ size_t mki_len = 0, ext_len = 0, i;
+
if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_SRTP_UNSET_PROFILE )
{
*olen = 0;
@@ -2593,12 +2613,19 @@
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding use_srtp extension" ) );
+ if( ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED &&
+ ssl->dtls_srtp_info.mki_len != 0 )
+ {
+ mki_len = ssl->dtls_srtp_info.mki_len;
+ }
+
/* extension */
buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP >> 8 ) & 0xFF );
buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP ) & 0xFF );
- /* total length (5: only one profile(2 bytes) and length(2bytes) and srtp_mki not supported so zero length(1byte) ) */
- buf[2] = 0x00;
- buf[3] = 0x05;
+ /* total length 5 and mki value: only one profile(2 bytes) and length(2 bytes) and srtp_mki ) */
+ ext_len = 5 + mki_len;
+ buf[2] = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
+ buf[3] = (unsigned char)( ext_len & 0xFF );
/* protection profile length: 2 */
buf[4] = 0x00;
@@ -2625,9 +2652,13 @@
return;
}
- buf[8] = 0x00; /* unsupported srtp_mki variable length vector set to 0 */
+ buf[8] = mki_len & 0xFF;
+ for( i=0; i < mki_len; i++ )
+ {
+ buf[ 9 + i ] = ssl->dtls_srtp_info.mki_value[i];
+ }
- *olen = 9;
+ *olen = 9 + mki_len;
}
#endif /* MBEDTLS_SSL_DTLS_SRTP */