RFC-6188 violation when FreeSWITCH is compiled with libs/srtp to use OpenSSL?
The cipher_id_type_t is set to AES_256_ICM, (if OpenSSL is NOT used then the cipher_id_type_t is set to AES_ICM).
This means that in srtp.c: srtp_protect_rtcp() and srtp_unprotect_rtcp() the wrong code path will be chosen for the ICM nonce and keystream will be reused on consecutive RTCP packets.
srtp_protect_rtcp() also srtp_unprotect_rtcp():
/*
* if we're using rindael counter mode, set nonce and seq
*/
if (stream->rtcp_cipher->type->id == AES_ICM) {
v128_t iv;
iv.v32[0] = 0;
As a result FS 1.6.15 is generating invalid SRTCP packets when AES-256 is being used (and libs/srtp is compiled to use OpenSSL).
Note: RTP explicitly checks for AES_ICM and AES_256_ICM so it is not affected. It will be affected if AES-192 is chosen. This is also seems to be in upstream.
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