--- /dev/null
+From f361e65dc2c90aaee9472f97b54083e0a2d49303 Mon Sep 17 00:00:00 2001
+From: Kevin Harwell <kharwell@digium.com>
+Date: Tue, 20 Aug 2019 15:05:45 -0500
+Subject: [PATCH] AST-2019-004 - res_pjsip_t38.c: Add NULL checks before using session media
+
+After receiving a 200 OK with a declined stream in response to a T.38
+initiated re-invite Asterisk would crash when attempting to dereference
+a NULL session media object.
+
+This patch checks to make sure the session media object is not NULL before
+attempting to use it.
+
+ASTERISK-28495
+patches:
+ ast-2019-004.patch submitted by Alexei Gradinari (license 5691)
+
+Change-Id: I168f45f4da29cfe739acf87e597baa2aae7aa572
+---
+
+--- a/res/res_pjsip_t38.c
++++ b/res/res_pjsip_t38.c
+@@ -202,7 +202,6 @@ static int t38_automatic_reject(void *ob
+ {
+ RAII_VAR(struct ast_sip_session *, session, obj, ao2_cleanup);
+ RAII_VAR(struct ast_datastore *, datastore, ast_sip_session_get_datastore(session, "t38"), ao2_cleanup);
+- struct ast_sip_session_media *session_media;
+
+ if (!datastore) {
+ return 0;
+@@ -211,8 +210,7 @@ static int t38_automatic_reject(void *ob
+ ast_debug(2, "Automatically rejecting T.38 request on channel '%s'\n",
+ session->channel ? ast_channel_name(session->channel) : "<gone>");
+
+- session_media = session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(session, session_media, datastore->data, T38_REJECTED);
++ t38_change_state(session, NULL, datastore->data, T38_REJECTED);
+ ast_sip_session_resume_reinvite(session);
+
+ return 0;
+@@ -312,28 +310,37 @@ static int t38_reinvite_response_cb(stru
+ int index;
+
+ session_media = session->active_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(session, session_media, state, T38_ENABLED);
++ if (!session_media) {
++ ast_log(LOG_WARNING, "Received %d response to T.38 re-invite on '%s' but no active session media\n",
++ status.code, session->channel ? ast_channel_name(session->channel) : "unknown channel");
++ } else {
++ t38_change_state(session, session_media, state, T38_ENABLED);
+
+- /* Stop all the streams in the stored away active state, they'll go back to being active once
+- * we reinvite back.
+- */
+- for (index = 0; index < AST_VECTOR_SIZE(&state->media_state->sessions); ++index) {
+- struct ast_sip_session_media *session_media = AST_VECTOR_GET(&state->media_state->sessions, index);
++ /* Stop all the streams in the stored away active state, they'll go back to being active once
++ * we reinvite back.
++ */
++ for (index = 0; index < AST_VECTOR_SIZE(&state->media_state->sessions); ++index) {
++ struct ast_sip_session_media *session_media = AST_VECTOR_GET(&state->media_state->sessions, index);
+
+- if (session_media && session_media->handler && session_media->handler->stream_stop) {
+- session_media->handler->stream_stop(session_media);
++ if (session_media && session_media->handler && session_media->handler->stream_stop) {
++ session_media->handler->stream_stop(session_media);
++ }
+ }
++
++ return 0;
+ }
+ } else {
+ session_media = session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(session, session_media, state, T38_REJECTED);
+-
+- /* Abort this attempt at switching to T.38 by resetting the pending state and freeing our stored away active state */
+- ast_sip_session_media_state_free(state->media_state);
+- state->media_state = NULL;
+- ast_sip_session_media_state_reset(session->pending_media_state);
+ }
+
++ /* If no session_media then response contained a declined stream, so disable */
++ t38_change_state(session, NULL, state, session_media ? T38_REJECTED : T38_DISABLED);
++
++ /* Abort this attempt at switching to T.38 by resetting the pending state and freeing our stored away active state */
++ ast_sip_session_media_state_free(state->media_state);
++ state->media_state = NULL;
++ ast_sip_session_media_state_reset(session->pending_media_state);
++
+ return 0;
+ }
+
+@@ -416,12 +423,10 @@ static int t38_interpret_parameters(void
+ /* Negotiation can not take place without a valid max_ifp value. */
+ if (!parameters->max_ifp) {
+ if (data->session->t38state == T38_PEER_REINVITE) {
+- session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(data->session, session_media, state, T38_REJECTED);
++ t38_change_state(data->session, NULL, state, T38_REJECTED);
+ ast_sip_session_resume_reinvite(data->session);
+ } else if (data->session->t38state == T38_ENABLED) {
+- session_media = data->session->active_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(data->session, session_media, state, T38_DISABLED);
++ t38_change_state(data->session, NULL, state, T38_DISABLED);
+ ast_sip_session_refresh(data->session, NULL, NULL, NULL,
+ AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, state->media_state);
+ state->media_state = NULL;
+@@ -444,6 +449,11 @@ static int t38_interpret_parameters(void
+ state->our_parms.version = MIN(state->our_parms.version, state->their_parms.version);
+ state->our_parms.rate_management = state->their_parms.rate_management;
+ session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
++ if (!session_media) {
++ ast_log(LOG_ERROR, "Failed to negotiate parameters for reinvite on channel '%s' (No pending session media).\n",
++ data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
++ break;
++ }
+ ast_udptl_set_local_max_ifp(session_media->udptl, state->our_parms.max_ifp);
+ t38_change_state(data->session, session_media, state, T38_ENABLED);
+ ast_sip_session_resume_reinvite(data->session);
+@@ -458,8 +468,13 @@ static int t38_interpret_parameters(void
+ }
+ state->our_parms = *parameters;
+ session_media = media_state->default_session[AST_MEDIA_TYPE_IMAGE];
++ if (!session_media) {
++ ast_log(LOG_ERROR, "Failed to negotiate parameters on channel '%s' (No default session media).\n",
++ data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
++ break;
++ }
+ ast_udptl_set_local_max_ifp(session_media->udptl, state->our_parms.max_ifp);
+- t38_change_state(data->session, session_media, state, T38_LOCAL_REINVITE);
++ t38_change_state(data->session, NULL, state, T38_LOCAL_REINVITE);
+ ast_sip_session_refresh(data->session, NULL, t38_reinvite_sdp_cb, t38_reinvite_response_cb,
+ AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, media_state);
+ }
+@@ -468,12 +483,10 @@ static int t38_interpret_parameters(void
+ case AST_T38_REFUSED:
+ case AST_T38_REQUEST_TERMINATE: /* Shutdown T38 */
+ if (data->session->t38state == T38_PEER_REINVITE) {
+- session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(data->session, session_media, state, T38_REJECTED);
++ t38_change_state(data->session, NULL, state, T38_REJECTED);
+ ast_sip_session_resume_reinvite(data->session);
+ } else if (data->session->t38state == T38_ENABLED) {
+- session_media = data->session->active_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
+- t38_change_state(data->session, session_media, state, T38_DISABLED);
++ t38_change_state(data->session, NULL, state, T38_DISABLED);
+ ast_sip_session_refresh(data->session, NULL, NULL, NULL, AST_SIP_SESSION_REFRESH_METHOD_INVITE, 1, state->media_state);
+ state->media_state = NULL;
+ }
+@@ -483,6 +496,11 @@ static int t38_interpret_parameters(void
+
+ if (data->session->t38state == T38_PEER_REINVITE) {
+ session_media = data->session->pending_media_state->default_session[AST_MEDIA_TYPE_IMAGE];
++ if (!session_media) {
++ ast_log(LOG_ERROR, "Failed to request parameters for reinvite on channel '%s' (No pending session media).\n",
++ data->session->channel ? ast_channel_name(data->session->channel) : "unknown channel");
++ break;
++ }
+ parameters.max_ifp = ast_udptl_get_far_max_ifp(session_media->udptl);
+ parameters.request_response = AST_T38_REQUEST_NEGOTIATE;
+ ast_queue_control_data(data->session->channel, AST_CONTROL_T38_PARAMETERS, ¶meters, sizeof(parameters));
+@@ -757,7 +775,7 @@ static int negotiate_incoming_sdp_stream
+
+ if ((session->t38state == T38_REJECTED) || (session->t38state == T38_DISABLED)) {
+ ast_debug(3, "Declining; T.38 state is rejected or declined\n");
+- t38_change_state(session, session_media, state, T38_DISABLED);
++ t38_change_state(session, NULL, state, T38_DISABLED);
+ return -1;
+ }
+
projects / feed / telephony.git / blobdiff