From 7d4e37a1805c97f20483b1b9cdb6ec5eb14aacc7 Mon Sep 17 00:00:00 2001 From: "Joshua C. Colp" Date: Tue, 16 Nov 2021 06:06:26 -0400 Subject: [PATCH] bridge: Deny full Local channel pair in bridge. Local channels are made up of two pairs - the 1 and 2 sides. When a frame goes in one side, it comes out the other. Back and forth. When both halves are in a bridge this creates an infinite loop of frames. This change makes it so that bridging no longer allows both of these sides to exist in the same bridge. ASTERISK-29748 Change-Id: I29928b6de87cd9be996a77daccefd7c360fef651 --- main/bridge_channel.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/main/bridge_channel.c b/main/bridge_channel.c index 71739b7b0f..aefb76405a 100644 --- a/main/bridge_channel.c +++ b/main/bridge_channel.c @@ -57,6 +57,7 @@ #include "asterisk/sem.h" #include "asterisk/stream.h" #include "asterisk/message.h" +#include "asterisk/core_local.h" /*! * \brief Used to queue an action frame onto a bridge channel and write an action frame into a bridge. @@ -2862,6 +2863,7 @@ int bridge_channel_internal_join(struct ast_bridge_channel *bridge_channel) int res = 0; uint8_t indicate_src_change = 0; struct ast_bridge_features *channel_features; + struct ast_channel *peer; struct ast_channel *swap; ast_debug(1, "Bridge %s: %p(%s) is joining\n", @@ -2876,6 +2878,29 @@ int bridge_channel_internal_join(struct ast_bridge_channel *bridge_channel) ast_channel_lock(bridge_channel->chan); + peer = ast_local_get_peer(bridge_channel->chan); + if (peer) { + struct ast_bridge *peer_bridge; + + ast_channel_lock(peer); + peer_bridge = ast_channel_internal_bridge(peer); + ast_channel_unlock(peer); + ast_channel_unref(peer); + + /* As we are only doing a pointer comparison we don't need the peer_bridge + * to be reference counted or locked. + */ + if (peer_bridge == bridge_channel->bridge) { + ast_channel_unlock(bridge_channel->chan); + ast_bridge_unlock(bridge_channel->bridge); + ast_debug(1, "Bridge %s: %p(%s) denying Bridge join to prevent Local channel loop\n", + bridge_channel->bridge->uniqueid, + bridge_channel, + ast_channel_name(bridge_channel->chan)); + return -1; + } + } + bridge_channel->read_format = ao2_bump(ast_channel_readformat(bridge_channel->chan)); bridge_channel->write_format = ao2_bump(ast_channel_writeformat(bridge_channel->chan));