linux-kernel - [PATCH 4.4 07/21] net: bridge: delete local fdb on device init failure

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Message-Id: <20190809134241.885705585@linuxfoundation.org>
Date:   Fri,  9 Aug 2019 15:45:11 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+88533dc8b582309bf3ee@...kaller.appspotmail.com,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.4 07/21] net: bridge: delete local fdb on device init failure

From: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>

[ 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: syzbot+88533dc8b582309bf3ee@...kaller.appspotmail.com
Fixes: 5be5a2df40f0 ("bridge: Add filtering support for default_pvid")
Signed-off-by: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/bridge/br_vlan.c |    5 +++++
 1 file changed, 5 insertions(+)

--- 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);