From: David Miller <davem@davemloft.net>
To: mikulas@artax.karlin.mff.cuni.cz
Cc: eric.dumazet@gmail.com, maxk@qualcomm.com, vtun@office.satix.net,
netdev@vger.kernel.org
Subject: Re: [PATCH] Crash in tun
Date: Fri, 20 Jul 2012 11:23:37 -0700 (PDT) [thread overview]
Message-ID: <20120720.112337.474955511809249636.davem@davemloft.net> (raw)
In-Reply-To: <alpine.DEB.2.00.1207191746170.7550@artax.karlin.mff.cuni.cz>
From: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Date: Thu, 19 Jul 2012 18:13:36 +0200 (CEST)
> tun: fix a crash bug and a memory leak
>
> This patch fixes a crash
> tun_chr_close -> netdev_run_todo -> tun_free_netdev -> sk_release_kernel ->
> sock_release -> iput(SOCK_INODE(sock))
> introduced by commit 1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d
>
> The problem is that this socket is embedded in struct tun_struct, it has
> no inode, iput is called on invalid inode, which modifies invalid memory
> and optionally causes a crash.
>
> sock_release also decrements sockets_in_use, this causes a bug that
> "sockets: used" field in /proc/*/net/sockstat keeps on decreasing when
> creating and closing tun devices.
>
> This patch introduces a flag SOCK_EXTERNALLY_ALLOCATED that instructs
> sock_release to not free the inode and not decrement sockets_in_use,
> fixing both memory corruption and sockets_in_use underflow.
>
> It should be backported to 3.3 an 3.4 stabke.
>
> Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
> Cc: stable@kernel.org
Applied.
next prev parent reply other threads:[~2012-07-20 18:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-19 1:12 [PATCH] Crash in tun Mikulas Patocka
2012-07-19 6:09 ` Eric Dumazet
2012-07-19 15:28 ` David Miller
2012-07-19 16:13 ` Mikulas Patocka
2012-07-19 17:44 ` Max Krasnyansky
2012-07-19 17:47 ` David Miller
2012-07-19 17:57 ` Max Krasnyansky
2012-07-20 18:23 ` David Miller [this message]
2012-07-21 7:55 ` Al Viro
2012-07-21 9:53 ` Nicholas A. Bellinger
2012-07-23 9:43 ` David Laight
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