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

5 files changed, 25 insertions, 16 deletions

diff --git a/res/res_pjsip.c b/res/res_pjsip.c
index a613bccf6..8be019f87 100644
--- a/res/res_pjsip.c
+++ b/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);
diff --git a/res/res_pjsip/pjsip_outbound_auth.c b/res/res_pjsip/pjsip_outbound_auth.c
index 1f754227a..8b39b000d 100644
--- a/res/res_pjsip/pjsip_outbound_auth.c
+++ b/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;
 	}
 
diff --git a/res/res_pjsip_outbound_authenticator_digest.c b/res/res_pjsip_outbound_authenticator_digest.c
index 35e59f21a..de77616fd 100644
--- a/res/res_pjsip_outbound_authenticator_digest.c
+++ b/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
diff --git a/res/res_pjsip_outbound_publish.c b/res/res_pjsip_outbound_publish.c
index 8b6f6e41e..f7669932e 100644
--- a/res/res_pjsip_outbound_publish.c
+++ b/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++;
diff --git a/res/res_pjsip_outbound_registration.c b/res/res_pjsip_outbound_registration.c
index 69e012448..c2eb62b32 100644
--- a/res/res_pjsip_outbound_registration.c
+++ b/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);
 	}