res_pjsip_outbound_registration: Don't fail on delayed processing.

Odd behaviors have been observed during outbound registrations. The most
common problem witnessed has been one where a request with
authentication credentials cannot be created after receiving a 401
response. Other behaviors include apparently processing an incorrect SIP
response.

Inspecting the code led to an apparent issue with regards to how we
handle transactions in outbound registration code. When a response to a
REGISTER arrives, we save a pointer to the transaction and then push a
task onto the registration serializer. Between the time that we save the
pointer and push the task, it's possible for the transaction to be
destroyed due to a timeout. It's also possible for the address to be
reused by the transaction layer for a new transaction.

To allow for authentication of a REGISTER request to be authenticated
after the transaction has timed out, we now hold a reference to the
original REGISTER request instead of the transaction. The function for
creating a request with authentication has been altered to take the
original request instead of the transaction where the original request
was sent.

ASTERISK-25020
Reported by Mark Michelson

Change-Id: I756c19ab05ada5d0503175db9676acf87c686d0a

include/asterisk/res_pjsip.h

@@ -697,13 +697,13 @@ struct ast_sip_outbound_authenticator {
 	 *
 	 * \param auths A vector of IDs of auth sorcery objects
 	 * \param challenge The SIP response with authentication challenge(s)
-	 * \param tsx The transaction in which the challenge was received
+	 * \param old_request The request that received the auth challenge(s)
 	 * \param new_request The new SIP request with challenge response(s)
 	 * \retval 0 Successfully created new request
 	 * \retval -1 Failed to create a new request
 	 */
 	int (*create_request_with_auth)(const struct ast_sip_auth_vector *auths, struct pjsip_rx_data *challenge,
-			struct pjsip_transaction *tsx, struct pjsip_tx_data **new_request);
+			struct pjsip_tx_data *old_request, struct pjsip_tx_data **new_request);
 };
 
 /*!
@@ -1396,7 +1396,7 @@ enum ast_sip_check_auth_result ast_sip_check_authentication(struct ast_sip_endpo
  * the parameters and return values.
  */
 int ast_sip_create_request_with_auth(const struct ast_sip_auth_vector *auths, pjsip_rx_data *challenge,
-		pjsip_transaction *tsx, pjsip_tx_data **new_request);
+		pjsip_tx_data *tdata, pjsip_tx_data **new_request);
 
 /*!
  * \brief Determine the endpoint that has sent a SIP message

res/res_pjsip.c

@@ -2009,13 +2009,13 @@ void ast_sip_unregister_outbound_authenticator(struct ast_sip_outbound_authentic
 }
 
 int ast_sip_create_request_with_auth(const struct ast_sip_auth_vector *auths, pjsip_rx_data *challenge,
-		pjsip_transaction *tsx, pjsip_tx_data **new_request)
+		pjsip_tx_data *old_request, pjsip_tx_data **new_request)
 {
 	if (!registered_outbound_authenticator) {
 		ast_log(LOG_WARNING, "No SIP outbound authenticator registered. Cannot respond to authentication challenge\n");
 		return -1;
 	}
-	return registered_outbound_authenticator->create_request_with_auth(auths, challenge, tsx, new_request);
+	return registered_outbound_authenticator->create_request_with_auth(auths, challenge, old_request, new_request);
 }
 
 struct endpoint_identifier_list {
@@ -3107,7 +3107,7 @@ static void send_request_cb(void *token, pjsip_event *e)
 			&& endpoint
 			&& ++req_data->challenge_count < MAX_RX_CHALLENGES /* Not in a challenge loop */
 			&& !ast_sip_create_request_with_auth(&endpoint->outbound_auths,
-				challenge, tsx, &tdata)
+				challenge, tsx->last_tx, &tdata)
 			&& endpt_send_request(endpoint, tdata, -1, req_data, send_request_cb)
 				== PJ_SUCCESS;
 		ao2_cleanup(endpoint);

res/res_pjsip/pjsip_outbound_auth.c

@@ -63,7 +63,7 @@ static pj_bool_t outbound_auth(pjsip_rx_data *rdata)
 		return PJ_FALSE;
 	}
 
-	if (ast_sip_create_request_with_auth(&endpoint->outbound_auths, rdata, tsx, &tdata)) {
+	if (ast_sip_create_request_with_auth(&endpoint->outbound_auths, rdata, tsx->last_tx, &tdata)) {
 		return PJ_FALSE;
 	}
 

res/res_pjsip_outbound_authenticator_digest.c

@@ -102,13 +102,13 @@ cleanup:
 }
 
 static int digest_create_request_with_auth(const struct ast_sip_auth_vector *auths, pjsip_rx_data *challenge,
-		pjsip_transaction *tsx, pjsip_tx_data **new_request)
+		pjsip_tx_data *old_request, pjsip_tx_data **new_request)
 {
 	pjsip_auth_clt_sess auth_sess;
 	pjsip_cseq_hdr *cseq;
 
 	if (pjsip_auth_clt_init(&auth_sess, ast_sip_get_pjsip_endpoint(),
-				tsx->pool, 0) != PJ_SUCCESS) {
+				old_request->pool, 0) != PJ_SUCCESS) {
 		ast_log(LOG_WARNING, "Failed to initialize client authentication session\n");
 		return -1;
 	}
@@ -119,7 +119,7 @@ static int digest_create_request_with_auth(const struct ast_sip_auth_vector *aut
 	}
 
 	switch (pjsip_auth_clt_reinit_req(&auth_sess, challenge,
-				tsx->last_tx, new_request)) {
+				old_request, new_request)) {
 	case PJ_SUCCESS:
 		/* PJSIP creates a new transaction for new_request (meaning it creates a new
 		 * branch). However, it recycles the Call-ID, from-tag, and CSeq from the

res/res_pjsip_outbound_publish.c

@@ -867,8 +867,10 @@ static void sip_outbound_publish_callback(struct pjsip_publishc_cbparam *param)
 	}
 
 	if (param->code == 401 || param->code == 407) {
+		pjsip_transaction *tsx = pjsip_rdata_get_tsx(param->rdata);
+
 		if (!ast_sip_create_request_with_auth(&publish->outbound_auths,
-				param->rdata, pjsip_rdata_get_tsx(param->rdata), &tdata)) {
+				param->rdata, tsx->last_tx, &tdata)) {
 			pjsip_publishc_send(client->client, tdata);
 		}
 		client->auth_attempts++;

res/res_pjsip_outbound_registration.c

@@ -568,8 +568,8 @@ struct registration_response {
 	struct sip_outbound_registration_client_state *client_state;
 	/*! \brief The response message */
 	pjsip_rx_data *rdata;
-	/*! \brief The response transaction */
-	pjsip_transaction *tsx;
+	/*! \brief Request for which the response was received */
+	pjsip_tx_data *old_request;
 };
 
 /*! \brief Registration response structure destructor */
@@ -581,6 +581,10 @@ static void registration_response_destroy(void *obj)
 		pjsip_rx_data_free_cloned(response->rdata);
 	}
 
+	if (response->old_request) {
+		pjsip_tx_data_dec_ref(response->old_request);
+	}
+
 	ao2_cleanup(response->client_state);
 }
 
@@ -633,19 +637,19 @@ static int handle_registration_response(void *data)
 	ast_copy_pj_str(client_uri, &info.client_uri, sizeof(client_uri));
 
 	if (response->client_state->status == SIP_REGISTRATION_STOPPED) {
-		ast_debug(1, "Not handling registration response from '%s' (transaction %s). Registration already stopped\n",
-				server_uri, response->tsx ? response->tsx->obj_name : "<none>");
+		ast_debug(1, "Not handling registration response from server '%s' for client '%s'. Registration already stopped\n",
+				server_uri, client_uri);
 		return 0;
 	}
 
-	ast_debug(1, "Processing REGISTER response %d from '%s' (transaction %s)\n",
-			response->code, server_uri, response->tsx ? response->tsx->obj_name : "<none>");
+	ast_debug(1, "Processing REGISTER response %d from server '%s' for client '%s'\n",
+			response->code, server_uri, client_uri);
 
 	if (!response->client_state->auth_attempted &&
 			(response->code == 401 || response->code == 407)) {
 		pjsip_tx_data *tdata;
 		if (!ast_sip_create_request_with_auth(&response->client_state->outbound_auths,
-				response->rdata, response->tsx, &tdata)) {
+				response->rdata, response->old_request, &tdata)) {
 			ao2_ref(response->client_state, +1);
 			response->client_state->auth_attempted = 1;
 			ast_debug(1, "Sending authenticated REGISTER to server '%s' from client '%s'\n",
@@ -748,9 +752,12 @@ static void sip_outbound_registration_response_cb(struct pjsip_regc_cbparam *par
 
 	if (param->rdata) {
 		struct pjsip_retry_after_hdr *retry_after = pjsip_msg_find_hdr(param->rdata->msg_info.msg, PJSIP_H_RETRY_AFTER, NULL);
+		pjsip_transaction *tsx;
 
 		response->retry_after = retry_after ? retry_after->ivalue : 0;
-		response->tsx = pjsip_rdata_get_tsx(param->rdata);
+		tsx = pjsip_rdata_get_tsx(param->rdata);
+		response->old_request = tsx->last_tx;
+		pjsip_tx_data_add_ref(response->old_request);
 		pjsip_rx_data_clone(param->rdata, 0, &response->rdata);
 	}