[gnutls-devel] Incorrect handshake message if MKI is specified for SRTP extension

Nikos Mavrogiannopoulos nmav at gnutls.org
Tue Jul 9 08:40:47 CEST 2013

On 07/08/2013 04:20 PM, Gábor Tatárka wrote:
> Hi,
> I'm trying to use gnutls 3.2.1 for DTLS-SRTP. The handshake seems to work fine if no MKI (master key identifier) is set. However, if I set an MKI (master key identifier) via gnutls_srtp_set_mki, the encoded message contains an incorrect size for the use_srtp extension. The length of the MKI is not included. This makes the receiving entity fail to decode the handshake message.
> The error itself is in the function _gnutls_srtp_send_params found in lib/ext/srtp.c. This function returns total_size + 1, but it should return total_size + 1 + priv->mki_size.
> I've checked the gnutls git repository and this bug is still there. Please see the attached patch file for a fix.

Hello Gabor,
 Thanks for noticing that. I've applied a fix.


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