From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org, philip.pettersson@gmail.com
Subject: Re: [PATCH net] packet: fix race condition in packet_set_ring
Date: Fri, 02 Dec 2016 12:17:16 -0500 (EST) [thread overview]
Message-ID: <20161202.121716.1777311750320989876.davem@davemloft.net> (raw)
In-Reply-To: <1480546536.18162.216.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 30 Nov 2016 14:55:36 -0800
> From: Philip Pettersson <philip.pettersson@gmail.com>
>
> When packet_set_ring creates a ring buffer it will initialize a
> struct timer_list if the packet version is TPACKET_V3. This value
> can then be raced by a different thread calling setsockopt to
> set the version to TPACKET_V1 before packet_set_ring has finished.
>
> This leads to a use-after-free on a function pointer in the
> struct timer_list when the socket is closed as the previously
> initialized timer will not be deleted.
>
> The bug is fixed by taking lock_sock(sk) in packet_setsockopt when
> changing the packet version while also taking the lock at the start
> of packet_set_ring.
>
> Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.")
> Signed-off-by: Philip Pettersson <philip.pettersson@gmail.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied and queued up for -stable, thanks.
prev parent reply other threads:[~2016-12-02 17:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 22:55 [PATCH net] packet: fix race condition in packet_set_ring Eric Dumazet
2016-12-02 17:17 ` David Miller [this message]
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