From: David Miller <davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: edumazet@google.com, eric.dumazet@gmail.com,
khlebnikov@yandex-team.ru, netdev@vger.kernel.org
Subject: Re: net: Fix skb csum races when peeking
Date: Wed, 15 Jul 2015 16:14:13 -0700 (PDT) [thread overview]
Message-ID: <20150715.161413.2184222881594096375.davem@davemloft.net> (raw)
In-Reply-To: <20150713120142.GA9787@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 13 Jul 2015 20:01:42 +0800
> When we calculate the checksum on the recv path, we store the
> result in the skb as an optimisation in case we need the checksum
> again down the line.
>
> This is in fact bogus for the MSG_PEEK case as this is done without
> any locking. So multiple threads can peek and then store the result
> to the same skb, potentially resulting in bogus skb states.
>
> This patch fixes this by only storing the result if the skb is not
> shared. This preserves the optimisations for the few cases where
> it can be done safely due to locking or other reasons, e.g., SIOCINQ.
>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Also applied and queued up for -stable, thanks!
next prev parent reply other threads:[~2015-07-15 23:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-10 11:51 [PATCH] netlink: enable skb header refcounting before sending first broadcast Konstantin Khlebnikov
2015-07-10 13:49 ` Eric Dumazet
2015-07-10 14:08 ` Konstantin Khlebnikov
2015-07-13 7:23 ` Herbert Xu
2015-07-13 8:04 ` net: Clone skb before setting peeked flag Herbert Xu
2015-07-15 23:13 ` David Miller
2015-07-13 8:05 ` [PATCH] netlink: enable skb header refcounting before sending first broadcast Eric Dumazet
2015-07-13 8:10 ` Herbert Xu
2015-07-13 8:22 ` Eric Dumazet
2015-07-13 8:25 ` Herbert Xu
2015-07-13 8:28 ` Eric Dumazet
2015-07-13 8:31 ` Herbert Xu
2015-07-13 12:01 ` net: Fix skb csum races when peeking Herbert Xu
2015-07-13 14:25 ` Herbert Xu
2015-07-14 6:11 ` Eric Dumazet
2015-07-15 23:14 ` David Miller [this message]
2015-07-13 8:54 ` [PATCH] netlink: enable skb header refcounting before sending first broadcast Konstantin Khlebnikov
2015-07-13 9:04 ` Herbert Xu
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