AST-2021-006 - res_pjsip_t38.c: Check for session_media on reinvite.

When Asterisk sends a reinvite negotiating T38 faxing, it's possible a
crash can occur if the response contains a m=image and zero port. The
reinvite callback code now checks session_media to see if it is null or
not before trying to access the udptl variable on it.

ASTERISK-29305

Change-Id: I1dfc51c5fa586e38579ede4bc228edee213ccaa9

diff --git a/res/res_pjsip_t38.c b/res/res_pjsip_t38.c
index 63abce5abf836a27b9db9e766e5374798f9e313c..5d7f68d09559ed8bbbd42a88b9e2b7ac7f86e94f 100644 (file)
--- a/res/res_pjsip_t38.c
+++ b/res/res_pjsip_t38.c
@@ -325,7 +325,7 @@ static int t38_reinvite_response_cb(struct ast_sip_session *session, pjsip_rx_da
                 * If there is a session_media object, but no udptl object available
                 * then it's assumed the stream was declined.
                 */
-               if (!session_media->udptl) {
+               if (session_media && !session_media->udptl) {
                        session_media = NULL;
                }