AST-2013-005: Fix crash caused by invalid SDP

If the SIP channel driver processes an invalid SDP that defines media
descriptions before connection information, it may attempt to reference
the socket address information even though that information has not yet
been set. This will cause a crash.

This patch adds checks when handling the various media descriptions that
ensures the media descriptions are handled only if we have connection
information suitable for that media.

Thanks to Walter Doekes, OSSO B.V., for reporting, testing, and providing
the solution to this problem.

(closes issue ASTERISK-22007)
Reported by: wdoekes
Tested by: wdoekes
patches:
  issueA22007_sdp_without_c_death.patch uploaded by wdoekes (License 5674)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@397756 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 71a640b2ed58abf57f33292fcd6abc5737a3e4af..181ce3901f52a0b1300c19d9bf24c35cabedb429 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -9721,7 +9721,7 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 
        /* Setup audio address and port */
        if (p->rtp) {
-               if (portno > 0) {
+               if (sa && portno > 0) {
                        ast_sockaddr_set_port(sa, portno);
                        ast_rtp_instance_set_remote_address(p->rtp, sa);
                        if (debug) {
@@ -9768,7 +9768,7 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 
        /* Setup video address and port */
        if (p->vrtp) {
-               if (vportno > 0) {
+               if (vsa && vportno > 0) {
                        ast_sockaddr_set_port(vsa, vportno);
                        ast_rtp_instance_set_remote_address(p->vrtp, vsa);
                        if (debug) {
@@ -9785,7 +9785,7 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 
        /* Setup text address and port */
        if (p->trtp) {
-               if (tportno > 0) {
+               if (tsa && tportno > 0) {
                        ast_sockaddr_set_port(tsa, tportno);
                        ast_rtp_instance_set_remote_address(p->trtp, tsa);
                        if (debug) {
@@ -9808,7 +9808,7 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
 
        /* Setup image address and port */
        if (p->udptl) {
-               if (udptlportno > 0) {
+               if (isa && udptlportno > 0) {
                        if (ast_test_flag(&p->flags[1], SIP_PAGE2_SYMMETRICRTP) && ast_test_flag(&p->flags[1], SIP_PAGE2_UDPTL_DESTINATION)) {
                                ast_rtp_instance_get_remote_address(p->rtp, isa);
                                if (!ast_sockaddr_isnull(isa) && debug) {