bridging: Ensure locking during snapshot creation

While the vast majority of bridge snapshot creation is locked properly,
there are currently some instances that are not. This adds the missing
locking to ensure bridge state is not malleable during snapshot
creation.

(closes issue ASTERISK-22904)
Review: https://reviewboard.asterisk.org/r/3415/
Reported by: Matt Jordan
........

Merged revisions 412193 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@412194 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 27 insertions, 3 deletions

diff --git a/main/bridge.c b/main/bridge.c
index 1baf01cfc..ee1e4a8e7 100644
--- a/main/bridge.c
+++ b/main/bridge.c
@@ -615,7 +615,10 @@ static struct stasis_message *create_bridge_snapshot_message(struct ast_bridge *
 {
 	RAII_VAR(struct ast_bridge_snapshot *, snapshot, NULL, ao2_cleanup);
 
+	ast_bridge_lock(bridge);
 	snapshot = ast_bridge_snapshot_create(bridge);
+	ast_bridge_unlock(bridge);
+
 	if (!snapshot) {
 		return NULL;
 	}
@@ -689,7 +692,9 @@ struct ast_bridge *bridge_register(struct ast_bridge *bridge)
 {
 	if (bridge) {
 		bridge->construction_completed = 1;
+		ast_bridge_lock(bridge);
 		ast_bridge_publish_state(bridge);
+		ast_bridge_unlock(bridge);
 		if (!ao2_link(bridges, bridge)) {
 			ast_bridge_destroy(bridge, 0);
 			bridge = NULL;
@@ -4067,7 +4072,9 @@ static void publish_blind_transfer(int is_external, enum ast_transfer_result res
 	struct ast_bridge_channel_pair pair;
 	pair.channel = transferer;
 	pair.bridge = bridge;
+	ast_bridge_lock(bridge);
 	ast_bridge_publish_blind_transfer(is_external, result, &pair, context, exten);
+	ast_bridge_unlock(bridge);
 }
 
 enum ast_transfer_result ast_bridge_transfer_blind(int is_external,
@@ -4294,7 +4301,7 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	RAII_VAR(struct ast_bridge_channel *, to_target_bridge_channel, NULL, ao2_cleanup);
 	RAII_VAR(struct ao2_container *, channels, NULL, ao2_cleanup);
 	RAII_VAR(struct ast_channel *, transferee, NULL, ao2_cleanup);
-	struct ast_bridge *the_bridge;
+	struct ast_bridge *the_bridge = NULL;
 	struct ast_channel *chan_bridged;
 	struct ast_channel *chan_unbridged;
 	int transfer_prohibited;
@@ -4412,8 +4419,10 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 	set_transfer_variables_all(to_transferee, channels, 1);
 
 	if (do_bridge_transfer) {
-		 res = attended_transfer_bridge(chan_bridged, chan_unbridged, the_bridge, NULL, &publication);
-		 goto end;
+		ast_bridge_lock(the_bridge);
+		res = attended_transfer_bridge(chan_bridged, chan_unbridged, the_bridge, NULL, &publication);
+		ast_bridge_unlock(the_bridge);
+		goto end;
 	}
 
 	transferee = get_transferee(channels, chan_bridged);
@@ -4430,7 +4439,9 @@ enum ast_transfer_result ast_bridge_transfer_attended(struct ast_channel *to_tra
 
 	ast_bridge_remove(the_bridge, chan_bridged);
 
+	ast_bridge_lock(the_bridge);
 	publish_attended_transfer_app(&publication, app);
+	ast_bridge_unlock(the_bridge);
 	res = AST_BRIDGE_TRANSFER_SUCCESS;
 
 end:
@@ -4438,7 +4449,20 @@ end:
 	 * All failure paths have deferred publishing a stasis message until this point
 	 */
 	if (res != AST_BRIDGE_TRANSFER_SUCCESS) {
+		if (to_transferee_bridge && to_target_bridge) {
+			ast_bridge_lock_both(to_transferee_bridge, to_target_bridge);
+		} else if (the_bridge) {
+			ast_bridge_lock(the_bridge);
+		}
+
 		publish_attended_transfer_fail(&publication, res);
+
+		if (to_transferee_bridge && to_target_bridge) {
+			ast_bridge_unlock(to_transferee_bridge);
+			ast_bridge_unlock(to_target_bridge);
+		} else if (the_bridge) {
+			ast_bridge_unlock(the_bridge);
+		}
 	}
 	stasis_publish_data_cleanup(&publication);
 	return res;