AST-2020-002 - res_pjsip: Stop sending INVITEs after challenge limit.

If Asterisk sends out an INVITE and receives a challenge with a
different nonce value each time, it will continuously send out INVITEs,
even if the call is hung up. The endpoint must be configured for
outbound authentication for this to occur. A limit has been set on
outbound INVITEs so that, once reached, Asterisk will stop sending
INVITEs and the transaction will terminate.

ASTERISK-29013

Change-Id: I2d001ca745b00ca8aa12030f2240cd72363b46f7

include/asterisk/res_pjsip.h

@@ -78,6 +78,9 @@ struct pjsip_tpselector;
 
 AST_VECTOR(ast_sip_service_route_vector, char *);
 
+/*! Maximum number of challenges before assuming that we are in a loop */
+#define MAX_RX_CHALLENGES	10
+
 /*!
  * \brief Structure for SIP transport information
  */

include/asterisk/res_pjsip_session.h

@@ -233,6 +233,8 @@ struct ast_sip_session {
 	AST_VECTOR(, struct ast_rtp_instance_stats *) media_stats;
 	/*! The direction of the call respective to Asterisk */
 	enum ast_sip_session_call_direction call_direction;
+	/*! Number of challenges received during outgoing requests to determine if we are in a loop */
+	unsigned int authentication_challenge_count:4;
 };
 
 typedef int (*ast_sip_session_request_creation_cb)(struct ast_sip_session *session, pjsip_tx_data *tdata);

res/res_pjsip.c

@@ -4445,8 +4445,6 @@ static pj_bool_t does_method_match(const pj_str_t *message_method, const char *s
 	return pj_stristr(&method, message_method) ? PJ_TRUE : PJ_FALSE;
 }
 
-/*! Maximum number of challenges before assuming that we are in a loop */
-#define MAX_RX_CHALLENGES	10
 #define TIMER_INACTIVE		0
 #define TIMEOUT_TIMER2		5
 

res/res_pjsip_session.c

@@ -2246,7 +2246,6 @@ static pjsip_module session_reinvite_module = {
 	.on_rx_request = session_reinvite_on_rx_request,
 };
 
-
 void ast_sip_session_send_request_with_cb(struct ast_sip_session *session, pjsip_tx_data *tdata,
 		ast_sip_session_response_cb on_response)
 {
@@ -2499,6 +2498,9 @@ struct ast_sip_session *ast_sip_session_alloc(struct ast_sip_endpoint *endpoint,
 		return NULL;
 	}
 
+	/* Track the number of challenges received on outbound requests */
+	session->authentication_challenge_count = 0;
+
 	/* Fire seesion begin handlers */
 	handle_session_begin(session);
 
@@ -2668,6 +2670,11 @@ static pj_bool_t outbound_invite_auth(pjsip_rx_data *rdata)
 
 	session = inv->mod_data[session_module.id];
 
+	if (++session->authentication_challenge_count > MAX_RX_CHALLENGES) {
+		ast_debug(3, "%s: Initial INVITE reached maximum number of auth attempts.\n", ast_sip_session_get_name(session));
+		return PJ_FALSE;
+	}
+
 	if (ast_sip_create_request_with_auth(&session->endpoint->outbound_auths, rdata,
 		tsx->last_tx, &tdata)) {
 		return PJ_FALSE;
@@ -4181,6 +4188,7 @@ static void session_inv_on_tsx_state_changed(pjsip_inv_session *inv, pjsip_trans
 						ast_debug(1, "reINVITE received final response code %d\n",
 							tsx->status_code);
 						if ((tsx->status_code == 401 || tsx->status_code == 407)
+							&& ++session->authentication_challenge_count < MAX_RX_CHALLENGES
 							&& !ast_sip_create_request_with_auth(
 								&session->endpoint->outbound_auths,
 								e->body.tsx_state.src.rdata, tsx->last_tx, &tdata)) {
@@ -4275,6 +4283,7 @@ static void session_inv_on_tsx_state_changed(pjsip_inv_session *inv, pjsip_trans
 						(int) pj_strlen(&tsx->method.name), pj_strbuf(&tsx->method.name),
 						tsx->status_code);
 					if ((tsx->status_code == 401 || tsx->status_code == 407)
+						&& ++session->authentication_challenge_count < MAX_RX_CHALLENGES
 						&& !ast_sip_create_request_with_auth(
 							&session->endpoint->outbound_auths,
 							e->body.tsx_state.src.rdata, tsx->last_tx, &tdata)) {