From f361e65dc2c90aaee9472f97b54083e0a2d49303 Mon Sep 17 00:00:00 2001 From: Kevin Harwell 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 --- diff --git a/res/res_pjsip_t38.c b/res/res_pjsip_t38.c index fae6fbb..624139f 100644 --- a/res/res_pjsip_t38.c +++ b/res/res_pjsip_t38.c @@ -203,7 +203,6 @@ { 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; @@ -212,8 +211,7 @@ ast_debug(2, "Automatically rejecting T.38 request on channel '%s'\n", session->channel ? ast_channel_name(session->channel) : ""); - 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; @@ -322,28 +320,37 @@ 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; } @@ -426,12 +433,10 @@ /* 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; @@ -454,6 +459,11 @@ 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); @@ -468,8 +478,13 @@ } 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); } @@ -478,12 +493,10 @@ 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; } @@ -493,6 +506,11 @@ 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)); @@ -788,7 +806,7 @@ 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 0; }