This is a note to let you know that I've just added the patch titled
neighbour: fix a race in neigh_destroy()
to the 3.4-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:
neighbour-fix-a-race-in-neigh_destroy.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c7035ea2b52ca2c60fa22c2fe24f582aa6c755e1 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Fri, 28 Jun 2013 02:37:42 -0700
Subject: neighbour: fix a race in neigh_destroy()
From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
[ Upstream commit c9ab4d85de222f3390c67aedc9c18a50e767531e ]
There is a race in neighbour code, because neigh_destroy() uses
skb_queue_purge(&neigh->arp_queue) without holding neighbour lock,
while other parts of the code assume neighbour rwlock is what
protects arp_queue
Convert all skb_queue_purge() calls to the __skb_queue_purge() variant
Use __skb_queue_head_init() instead of skb_queue_head_init()
to make clear we do not use arp_queue.lock
And hold neigh->lock in neigh_destroy() to close the race.
Reported-by: Joe Jin <joe.jin@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/neighbour.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -237,7 +237,7 @@ static void neigh_flush_dev(struct neigh
we must kill timers etc. and move
it to safe state.
*/
- skb_queue_purge(&n->arp_queue);
+ __skb_queue_purge(&n->arp_queue);
n->arp_queue_len_bytes = 0;
n->output = neigh_blackhole;
if (n->nud_state & NUD_VALID)
@@ -300,7 +300,7 @@ static struct neighbour *neigh_alloc(str
if (!n)
goto out_entries;
- skb_queue_head_init(&n->arp_queue);
+ __skb_queue_head_init(&n->arp_queue);
rwlock_init(&n->lock);
seqlock_init(&n->ha_lock);
n->updated = n->used = now;
@@ -721,7 +721,9 @@ void neigh_destroy(struct neighbour *nei
if (neigh_del_timer(neigh))
printk(KERN_WARNING "Impossible event.\n");
- skb_queue_purge(&neigh->arp_queue);
+ write_lock_bh(&neigh->lock);
+ __skb_queue_purge(&neigh->arp_queue);
+ write_unlock_bh(&neigh->lock);
neigh->arp_queue_len_bytes = 0;
if (dev->netdev_ops->ndo_neigh_destroy)
@@ -867,7 +869,7 @@ static void neigh_invalidate(struct neig
neigh->ops->error_report(neigh, skb);
write_lock(&neigh->lock);
}
- skb_queue_purge(&neigh->arp_queue);
+ __skb_queue_purge(&neigh->arp_queue);
neigh->arp_queue_len_bytes = 0;
}
@@ -1206,7 +1208,7 @@ int neigh_update(struct neighbour *neigh
write_lock_bh(&neigh->lock);
}
- skb_queue_purge(&neigh->arp_queue);
+ __skb_queue_purge(&neigh->arp_queue);
neigh->arp_queue_len_bytes = 0;
}
out:
Patches currently in stable-queue which might be from eric.dumazet@xxxxxxxxx are
queue-3.4/neighbour-fix-a-race-in-neigh_destroy.patch
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