AST-2018-005: Fix tdata leaks when calling pjsip_endpt_send_response(2)

pjsip_distributor:
   authenticate() creates a tdata and uses it to send a challenge or
   failure response.  When pjsip_endpt_send_response2() succeeds, it
   automatically decrements the tdata ref count but when it fails, it
   doesn't.  Since we weren't checking for a return status, we weren't
   decrementing the count ourselves on error and were therefore leaking
   tdatas.

res_pjsip_session:
   session_reinvite_on_rx_request wasn't decrementing the ref count
   if an error happened while sending a 491 response.
   pre_session_setup wasn't decrementing the ref count if
   while sending an error after a pjsip_inv_verify_request failure.

res_pjsip:
   ast_sip_send_response wasn't decrementing the ref count on error.

ASTERISK-27618
Reported By: Sandro Gauci

Change-Id: Iab33a6c7b6fba96148ed465b690ba8534ac961bf

res/res_pjsip.c

@@ -4424,9 +4424,15 @@ static void supplement_outgoing_response(pjsip_tx_data *tdata, struct ast_sip_en
 
 int ast_sip_send_response(pjsip_response_addr *res_addr, pjsip_tx_data *tdata, struct ast_sip_endpoint *sip_endpoint)
 {
+	pj_status_t status;
+
 	supplement_outgoing_response(tdata, sip_endpoint);
+	status = pjsip_endpt_send_response(ast_sip_get_pjsip_endpoint(), res_addr, tdata, NULL, NULL);
+	if (status != PJ_SUCCESS) {
+		pjsip_tx_data_dec_ref(tdata);
+	}
 
-	return pjsip_endpt_send_response(ast_sip_get_pjsip_endpoint(), res_addr, tdata, NULL, NULL);
+	return status == PJ_SUCCESS ? 0 : -1;
 }
 
 int ast_sip_send_stateful_response(pjsip_rx_data *rdata, pjsip_tx_data *tdata, struct ast_sip_endpoint *sip_endpoint)

res/res_pjsip/pjsip_distributor.c

@@ -854,7 +854,9 @@ static pj_bool_t authenticate(pjsip_rx_data *rdata)
 		case AST_SIP_AUTHENTICATION_CHALLENGE:
 			/* Send the 401 we created for them */
 			ast_sip_report_auth_challenge_sent(endpoint, rdata, tdata);
-			pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL);
+			if (pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL) != PJ_SUCCESS) {
+				pjsip_tx_data_dec_ref(tdata);
+			}
 			return PJ_TRUE;
 		case AST_SIP_AUTHENTICATION_SUCCESS:
 			/* See note in endpoint_lookup about not holding an unnecessary write lock */
@@ -867,7 +869,9 @@ static pj_bool_t authenticate(pjsip_rx_data *rdata)
 		case AST_SIP_AUTHENTICATION_FAILED:
 			log_failed_request(rdata, "Failed to authenticate", 0, 0);
 			ast_sip_report_auth_failed_challenge_response(endpoint, rdata);
-			pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL);
+			if (pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL) != PJ_SUCCESS) {
+				pjsip_tx_data_dec_ref(tdata);
+			}
 			return PJ_TRUE;
 		case AST_SIP_AUTHENTICATION_ERROR:
 			log_failed_request(rdata, "Error to authenticate", 0, 0);

res/res_pjsip_session.c

@@ -1083,7 +1083,9 @@ static pj_bool_t session_reinvite_on_rx_request(pjsip_rx_data *rdata)
 
 		/* Otherwise this is a new re-invite, so reject it */
 		if (pjsip_dlg_create_response(dlg, rdata, 491, NULL, &tdata) == PJ_SUCCESS) {
-			pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL);
+			if (pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL) != PJ_SUCCESS) {
+				pjsip_tx_data_dec_ref(tdata);
+			}
 		}
 
 		return PJ_TRUE;
@@ -2045,7 +2047,9 @@ static pjsip_inv_session *pre_session_setup(pjsip_rx_data *rdata, const struct a
 
 	if (pjsip_inv_verify_request(rdata, &options, NULL, NULL, ast_sip_get_pjsip_endpoint(), &tdata) != PJ_SUCCESS) {
 		if (tdata) {
-			pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL);
+			if (pjsip_endpt_send_response2(ast_sip_get_pjsip_endpoint(), rdata, tdata, NULL, NULL) != PJ_SUCCESS) {
+				pjsip_tx_data_dec_ref(tdata);
+			}
 		} else {
 			pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 500, NULL, NULL, NULL);
 		}