Bridge system: Fix memory leaks and double frees on impart failure.

You cannot reference the passed in features struct after calling
ast_bridge_impart().  Even if the call fails.

Change-Id: I902b88ba0d5d39520e670fb635078a367268ea21

5 files changed, 12 insertions, 7 deletions

diff --git a/apps/confbridge/conf_chan_announce.c b/apps/confbridge/conf_chan_announce.c
index 8ced0cccd..ff3049908 100644
--- a/apps/confbridge/conf_chan_announce.c
+++ b/apps/confbridge/conf_chan_announce.c
@@ -199,7 +199,6 @@ int conf_announce_channel_push(struct ast_channel *ast)
 	/* Impart the output channel into the bridge */
 	if (ast_bridge_impart(p->bridge, chan, NULL, features,
 		AST_BRIDGE_IMPART_CHAN_DEPARTABLE)) {
-		ast_bridge_features_destroy(features);
 		ast_channel_unref(chan);
 		return -1;
 	}
diff --git a/include/asterisk/features.h b/include/asterisk/features.h
index b63124c2f..a4aed5d18 100644
--- a/include/asterisk/features.h
+++ b/include/asterisk/features.h
@@ -51,6 +51,7 @@ int ast_bridge_call(struct ast_channel *chan, struct ast_channel *peer, struct a
 /*!
  * \brief Bridge a call, and add additional flags to the bridge
  *
+ * \details
  * This does the same thing as \ref ast_bridge_call, except that once the bridge
  * is created, the provided flags are set on the bridge. The provided flags are
  * added to the bridge's flags; they will not clear any flags already set.
@@ -70,6 +71,7 @@ int ast_bridge_call_with_flags(struct ast_channel *chan, struct ast_channel *pee
  * \brief Add an arbitrary channel to a bridge
  * \since 12.0.0
  *
+ * \details
  * The channel that is being added to the bridge can be in any state: unbridged,
  * bridged, answered, unanswered, etc. The channel will be added asynchronously,
  * meaning that when this function returns once the channel has been added to
@@ -87,11 +89,16 @@ int ast_bridge_call_with_flags(struct ast_channel *chan, struct ast_channel *pee
  * \param features Features for this channel in the bridge
  * \param play_tone Indicates if a tone should be played to the channel
  * \param xfersound Sound that should be used to indicate transfer with play_tone
+ *
+ * \note The features parameter must be NULL or obtained by
+ * ast_bridge_features_new().  You must not dereference features
+ * after calling even if the call fails.
+ *
  * \retval 0 Success
  * \retval -1 Failure
  */
 int ast_bridge_add_channel(struct ast_bridge *bridge, struct ast_channel *chan,
-		struct ast_bridge_features *features, int play_tone, const char *xfersound);
+	struct ast_bridge_features *features, int play_tone, const char *xfersound);
 
 
 
diff --git a/main/bridge.c b/main/bridge.c
index a56555bc9..64c750b1e 100644
--- a/main/bridge.c
+++ b/main/bridge.c
@@ -2318,6 +2318,9 @@ int ast_bridge_add_channel(struct ast_bridge *bridge, struct ast_channel *chan,
 	if (chan_bridge) {
 		struct ast_bridge_channel *bridge_channel;
 
+		/* The channel is in a bridge so it is not getting any new features. */
+		ast_bridge_features_destroy(features);
+
 		ast_bridge_lock_both(bridge, chan_bridge);
 		bridge_channel = bridge_find_channel(chan_bridge, chan);
 
@@ -2340,9 +2343,6 @@ int ast_bridge_add_channel(struct ast_bridge *bridge, struct ast_channel *chan,
 		bridge_dissolve_check_stolen(chan_bridge, bridge_channel);
 		ast_bridge_unlock(chan_bridge);
 		ast_bridge_unlock(bridge);
-
-		/* The channel was in a bridge so it is not getting any new features. */
-		ast_bridge_features_destroy(features);
 	} else {
 		/* Slightly less easy case. We need to yank channel A from
 		 * where he currently is and impart him into our bridge.
@@ -2350,6 +2350,7 @@ int ast_bridge_add_channel(struct ast_bridge *bridge, struct ast_channel *chan,
 		yanked_chan = ast_channel_yank(chan);
 		if (!yanked_chan) {
 			ast_log(LOG_WARNING, "Could not gain control of channel %s\n", ast_channel_name(chan));
+			ast_bridge_features_destroy(features);
 			return -1;
 		}
 		if (ast_channel_state(yanked_chan) != AST_STATE_UP) {
diff --git a/main/core_unreal.c b/main/core_unreal.c
index 377abd1ff..28886b635 100644
--- a/main/core_unreal.c
+++ b/main/core_unreal.c
@@ -805,7 +805,6 @@ int ast_unreal_channel_push_to_bridge(struct ast_channel *ast, struct ast_bridge
 	/* Impart the semi2 channel into the bridge */
 	if (ast_bridge_impart(bridge, chan, NULL, features,
 		AST_BRIDGE_IMPART_CHAN_INDEPENDENT)) {
-		ast_bridge_features_destroy(features);
 		ast_channel_unref(chan);
 		return -1;
 	}
diff --git a/main/features.c b/main/features.c
index 618f91c52..7dfe4cde5 100644
--- a/main/features.c
+++ b/main/features.c
@@ -1103,7 +1103,6 @@ static int bridge_exec(struct ast_channel *chan, const char *data)
 		xfer_cfg ? xfer_cfg->xfersound : NULL);
 	ao2_cleanup(xfer_cfg);
 	if (bridge_add_failed) {
-		ast_bridge_features_destroy(peer_features);
 		ast_bridge_features_cleanup(&chan_features);
 		ast_bridge_destroy(bridge, 0);
 		goto done;