res_pjsip_caller_id: Fix crash on session timers UPDATE on inbound calls.

The res_pjsip_caller_id module wrongly assumed that a
saved From header would always exist on sessions. This
is true until an inbound call is received and a session
timer causes an UPDATE to be sent. In this case there will
be no saved From header and a crash will occur. This change
makes it fall back to the From header of the outgoing request
if no saved From header is present.

ASTERISK-26307 #close

Change-Id: Iccc3bc8d243b5ede9b81abf960292930c908d4fa

res/res_pjsip_caller_id.c

@@ -523,8 +523,11 @@ static void add_pai_header(const struct ast_sip_session *session, pjsip_tx_data
 		}
 	}
 
-	base = tdata->msg->type == PJSIP_REQUEST_MSG ? session->saved_from_hdr :
-		PJSIP_MSG_TO_HDR(tdata->msg);
+	if (tdata->msg->type == PJSIP_REQUEST_MSG) {
+		base = session->saved_from_hdr ? session->saved_from_hdr : PJSIP_MSG_FROM_HDR(tdata->msg);
+	} else {
+		base = PJSIP_MSG_TO_HDR(tdata->msg);
+	}
 
 	pai_hdr = create_new_id_hdr(&pj_pai_name, base, tdata, id);
 	if (!pai_hdr) {
@@ -629,8 +632,11 @@ static void add_rpid_header(const struct ast_sip_session *session, pjsip_tx_data
 		}
 	}
 
-	base = tdata->msg->type == PJSIP_REQUEST_MSG ? session->saved_from_hdr :
-		PJSIP_MSG_TO_HDR(tdata->msg);
+	if (tdata->msg->type == PJSIP_REQUEST_MSG) {
+		base = session->saved_from_hdr ? session->saved_from_hdr : PJSIP_MSG_FROM_HDR(tdata->msg);
+	} else {
+		base = PJSIP_MSG_TO_HDR(tdata->msg);
+	}
 
 	rpid_hdr = create_new_id_hdr(&pj_rpid_name, base, tdata, id);
 	if (!rpid_hdr) {