This is a note to let you know that I've just added the patch titled
bridge: fix NULL pointer deref of br_port_get_rcu
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bridge-fix-null-pointer-deref-of-br_port_get_rcu.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 95198d0a67841846139a0ddfb0ebf5dbc034e3c3 Mon Sep 17 00:00:00 2001
From: Hong Zhiguo <zhiguohong@xxxxxxxxxxx>
Date: Sat, 14 Sep 2013 22:42:28 +0800
Subject: bridge: fix NULL pointer deref of br_port_get_rcu
From: Hong Zhiguo <zhiguohong@xxxxxxxxxxx>
[ Upstream commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2 ]
The NULL deref happens when br_handle_frame is called between these
2 lines of del_nbp:
dev->priv_flags &= ~IFF_BRIDGE_PORT;
/* --> br_handle_frame is called at this time */
netdev_rx_handler_unregister(dev);
In br_handle_frame the return of br_port_get_rcu(dev) is dereferenced
without check but br_port_get_rcu(dev) returns NULL if:
!(dev->priv_flags & IFF_BRIDGE_PORT)
Eric Dumazet pointed out the testing of IFF_BRIDGE_PORT is not necessary
here since we're in rcu_read_lock and we have synchronize_net() in
netdev_rx_handler_unregister. So remove the testing of IFF_BRIDGE_PORT
and by the previous patch, make sure br_port_get_rcu is called in
bridging code.
Signed-off-by: Hong Zhiguo <zhiguohong@xxxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/bridge/br_private.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -202,10 +202,7 @@ struct net_bridge_port
static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *dev)
{
- struct net_bridge_port *port =
- rcu_dereference_rtnl(dev->rx_handler_data);
-
- return br_port_exists(dev) ? port : NULL;
+ return rcu_dereference(dev->rx_handler_data);
}
static inline struct net_bridge_port *br_port_get_rtnl(const struct net_device *dev)
Patches currently in stable-queue which might be from zhiguohong@xxxxxxxxxxx are
queue-3.11/bridge-use-br_port_get_rtnl-within-rtnl-lock.patch
queue-3.11/bridge-fix-null-pointer-deref-of-br_port_get_rcu.patch
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