res_pjsip: Prevent access of NULL channels.

It is possible to receive incoming requests or responses after the channel
on an ast_sip_session has been destroyed and NULLed out. Handlers of these
sorts of requests or responses need to be prepared for the possibility
that the channel is NULL or else they could cause a crash.

While several places have been amended to deal with NULL channels, there
were still a couple of places that needed updating.

res_pjsip_dtmf_info.c: When handling incoming INFO requests, we need to
return early if there is no channel on the session.

res_pjsip_session.c: When handling a 302 response, we need to stop the
redirecting attempt if there is no channel on the session.

ASTERISK-25148 #close
reported by Mark Michelson

Change-Id: Id1a75ffc3d0eaa168b0b28188fb54d6cf9fc47a9

diff --git a/res/res_pjsip_dtmf_info.c b/res/res_pjsip_dtmf_info.c
index b0a6649a0bccebfc0643c7d5b6585d3b282138b8..7b52250c829a21639d581dc06565db727b9d665e 100644 (file)
--- a/res/res_pjsip_dtmf_info.c
+++ b/res/res_pjsip_dtmf_info.c
@@ -89,7 +89,13 @@ static int dtmf_info_incoming_request(struct ast_sip_session *session, struct pj
        char event = '\0';
        unsigned int duration = 100;
 
-       char is_dtmf = is_media_type(rdata, "dtmf");
+       char is_dtmf;
+
+       if (!session->channel) {
+               return 0;
+       }
+
+       is_dtmf = is_media_type(rdata, "dtmf");
 
        if (!is_dtmf && !is_media_type(rdata, "dtmf-relay")) {
                return 0;

diff --git a/res/res_pjsip_session.c b/res/res_pjsip_session.c
index 3475e80b795d39b0ce0fa1af9bcbd298ac8a1705..a8f8cba8504522b1fbd37fceab94c5fa0885942b 100644 (file)
--- a/res/res_pjsip_session.c
+++ b/res/res_pjsip_session.c
@@ -2627,6 +2627,10 @@ static pjsip_redirect_op session_inv_on_redirected(pjsip_inv_session *inv, const
        struct ast_sip_session *session = inv->mod_data[session_module.id];
        const pjsip_sip_uri *uri;
 
+       if (!session->channel) {
+               return PJSIP_REDIRECT_STOP;
+       }
+
        if (session->endpoint->redirect_method == AST_SIP_REDIRECT_URI_PJSIP) {
                return PJSIP_REDIRECT_ACCEPT;
        }