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Message-Id: <20130511.162721.884139879091826308.davem@davemloft.net>
Date: Sat, 11 May 2013 16:27:21 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: eric.dumazet@...il.com
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH] ipv6: do not clear pinet6 field
From: Eric Dumazet <eric.dumazet@...il.com>
Date: Thu, 09 May 2013 13:28:16 -0700
> From: Eric Dumazet <edumazet@...gle.com>
>
> We have seen multiple NULL dereferences in __inet6_lookup_established()
>
> After analysis, I found that inet6_sk() could be NULL while the
> check for sk_family == AF_INET6 was true.
>
> Bug was added in linux-2.6.29 when RCU lookups were introduced in UDP
> and TCP stacks.
>
> Once an IPv6 socket, using SLAB_DESTROY_BY_RCU is inserted in a hash
> table, we no longer can clear pinet6 field.
>
> This patch extends logic used in commit fcbdf09d9652c891
> ("net: fix nulls list corruptions in sk_prot_alloc")
>
> TCP/UDP/UDPLite IPv6 protocols provide their own .clear_sk() method
> to make sure we do not clear pinet6 field.
>
> At socket clone phase, we do not really care, as cloning the parent (non
> NULL) pinet6 is not adding a fatal race.
>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Applied and queued up for -stable, thanks!
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