[sr-dev] Crash on a 302 with empty Contact header

[Javi Gallart]

Hello

lately we have seen some crashes in Kamailio 4.2.1. After some 
investigation we found that the crashes happen when get_redirects(*) is 
called in a failure_route on a 302 message containing a Contact header 
like this:

Contact: <>

It's easy to duplicate. This is a sample backtrace:

Core was generated by `/usr/local/kamailio/sbin/kamailio -P 
/var/run/kamailio/kamailio.pid -f'.
Program terminated with signal 11, Segmentation fault.
#0  0x00000000004737dc in append_branch (msg=0x0, uri=0x7f4cfc3ba308, 
dst_uri=0x0, path=0x0, q=10, flags=0, force_socket=0x0, 
instance=0x7f4cf8ae3b70, reg_id=0, ruid=0x7f4cf8ae3b70, 
location_ua=0x7f4cf8ae3b70)
     at dset.c:344
344                     if (msg->new_uri.s)
Missing separate debuginfos, use: debuginfo-install 
glibc-2.12-1.149.el6.x86_64 pcre-7.8-6.el6.x86_64
(gdb) bt
#0  0x00000000004737dc in append_branch (msg=0x0, uri=0x7f4cfc3ba308, 
dst_uri=0x0, path=0x0, q=10, flags=0, force_socket=0x0, 
instance=0x7f4cf8ae3b70, reg_id=0, ruid=0x7f4cf8ae3b70, 
location_ua=0x7f4cf8ae3b70)
     at dset.c:344
#1  0x00007f4cf88dc843 in shmcontact2dset (req=0x7f4cfb56fb80, 
sh_rpl=0x7f4cfc43f080, max=-1, reason=0x0, bflags=0) at rd_funcs.c:303
#2  0x00007f4cf88da242 in get_redirect (msg=0x7f4cfb56fb80, maxt=0, 
maxb=0, reason=0x0, bflags=0) at rd_funcs.c:106
#3  0x00007f4cf88e036b in w_get_redirect2 (msg=0x7f4cfb56fb80, 
max_c=0x0, reason=0x0) at redirect.c:369
#4  0x00007f4cf88e03ba in w_get_redirect1 (msg=0x7f4cfb56fb80, 
max_c=0x0, foo=0x0) at redirect.c:380
#5  0x000000000041d329 in do_action (h=0x7fffcf6c27e0, a=0x7f4cfc4144f8, 
msg=0x7f4cfb56fb80) at action.c:1094
#6  0x00000000004299b1 in run_actions (h=0x7fffcf6c27e0, 
a=0x7f4cfc4141e0, msg=0x7f4cfb56fb80) at action.c:1583
#7  0x000000000041d204 in do_action (h=0x7fffcf6c27e0, a=0x7f4cfc41f3e8, 
msg=0x7f4cfb56fb80) at action.c:1079
#8  0x00000000004299b1 in run_actions (h=0x7fffcf6c27e0, 
a=0x7f4cfc412028, msg=0x7f4cfb56fb80) at action.c:1583
#9  0x000000000042a0de in run_top_route (a=0x7f4cfc412028, 
msg=0x7f4cfb56fb80, c=0x0) at action.c:1669
#10 0x00007f4cfb2f468e in run_failure_handlers (t=0x7f4c01c524a0, 
rpl=0x7f4cfc43f080, code=302, extra_flags=64) at t_reply.c:1051
#11 0x00007f4cfb2f72ae in t_should_relay_response (Trans=0x7f4c01c524a0, 
new_code=302, branch=0, should_store=0x7fffcf6c2b30, 
should_relay=0x7fffcf6c2b34, cancel_data=0x7fffcf6c2d80, 
reply=0x7f4cfc43f080)
     at t_reply.c:1406
#12 0x00007f4cfb2f9e0f in relay_reply (t=0x7f4c01c524a0, 
p_msg=0x7f4cfc43f080, branch=0, msg_status=302, 
cancel_data=0x7fffcf6c2d80, do_put_on_wait=1) at t_reply.c:1809
#13 0x00007f4cfb2fe40c in reply_received (p_msg=0x7f4cfc43f080) at 
t_reply.c:2493
#14 0x000000000048bb02 in do_forward_reply (msg=0x7f4cfc43f080, mode=0) 
at forward.c:783
#15 0x000000000048d13d in forward_reply (msg=0x7f4cfc43f080) at 
forward.c:885
#16 0x0000000000507978 in receive_msg (
     buf=0xa6e740 "SIP/2.0 302 Redirect Request\r\nVia: SIP/2.0/UDP 
79.170.68.186;branch=z9hG4bK1472.15af91d174dcfc95d1b65dfeebfde5aa.0\r\nVia: 
SIP/2.0/UDP 
79.170.64.167:5080;received=79.170.64.167;rport=5080;branch=z9hG4bK"..., 
len=529, rcv_info=0x7fffcf6c31a0) at receive.c:275
#17 0x000000000060679e in udp_rcv_loop () at udp_server.c:521
#18 0x00000000004a5ab3 in main_loop () at main.c:1629
#19 0x00000000004aad46 in main (argc=13, argv=0x7fffcf6c35b8) at 
main.c:2561

Can you take a look?

Thanks

Javi