0x0 memory read in transport_zrtp.c - support for pjsip 2.8 onwards

[welljsjs]

The C wrapper for pjsua seems to have some unwanted behaviour.

After accepting an incoming call, before transmitting media, I experience hard crashes due to a memory read at 0x0.

The error occurs on line 992 within transport_zrtp.c.

zrtp->stream_rtp_cb is NULL.

att_param->rtp_cb; is NULL as well.

I am not quite sure whether this problem is somehow related to the recent upgrade to OpenSSL 1.1.0 (in ZRTPCPP), I haven't yet looked into it really (concerning the wrapper).

I simply used the example provided in this repository to make ZRTP available to pjsua.

I know it's hard to maintain this repository, especially if you've limited time to care about things like this which are not related to your work or what you do for a living. However, I'd absolutely appreciate some help.

Thread 10#0	0x0000000000000000 in 0x00000000 ()
#1	0x0000000100607170 in transport_rtp_cb ()
#2	0x000000010089cdec in srtp_rtp_cb ()
#3	0x00000001008a1c9c in call_rtp_cb ()
#4	0x000000010089fa00 in on_rx_rtp ()
#5	0x000000010091934c in ioqueue_dispatch_read_event ()
#6	0x000000010091bf80 in pj_ioqueue_poll ()
#7	0x000000010086cadc in worker_proc ()
#8	0x000000010091e404 in thread_main ()
#9	0x000000019fd391ec in _pthread_start ()

27/09/‘19: might be related to pjsip/pjproject@106ec87#diff-c2a444132012a8574cc6001cca81feb1
the introduction of rtp_cb2.