net: bridge: delete local fdb on device init failure [Linux 4.4.189]

This Linux kernel change "net: bridge: delete local fdb on device init failure" is included in the Linux 4.4.189 release. This change is authored by Nikolay Aleksandrov <nikolay [at] cumulusnetworks.com> on Mon Jul 29 12:28:41 2019 +0300. The commit for this change in Linux stable tree is 8db1305 (patch) which is from upstream commit d7bae09. The same Linux upstream change may have been applied to various maintained Linux releases and you can find all Linux releases containing changes from upstream d7bae09.

net: bridge: delete local fdb on device init failure

[ Upstream commit d7bae09fa008c6c9a489580db0a5a12063b97f97 ]

On initialization failure we have to delete the local fdb which was
inserted due to the default pvid creation. This problem has been present
since the inception of default_pvid. Note that currently there are 2 cases:
1) in br_dev_init() when br_multicast_init() fails
2) if register_netdevice() fails after calling ndo_init()

This patch takes care of both since br_vlan_flush() is called on both
occasions. Also the new fdb delete would be a no-op on normal bridge
device destruction since the local fdb would've been already flushed by
br_dev_delete(). This is not an issue for ports since nbp_vlan_init() is
called last when adding a port thus nothing can fail after it.

Reported-by: [email protected]
Fixes: 5be5a2df40f0 ("bridge: Add filtering support for default_pvid")
Signed-off-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

There are 5 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 net/bridge/br_vlan.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 1394da6..a795396 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -580,6 +580,11 @@ void br_vlan_flush(struct net_bridge *br)

    ASSERT_RTNL();

+   /* delete auto-added default pvid local fdb before flushing vlans
+    * otherwise it will be leaked on bridge device init failure
+    */
+   br_fdb_delete_by_port(br, NULL, 0, 1);
+
    vg = br_vlan_group(br);
    __vlan_flush(vg);
    RCU_INIT_POINTER(br->vlgrp, NULL);

Leave a Reply

Your email address will not be published. Required fields are marked *