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From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: andreyknvl@google.com, edumazet@google.com, idaifish@gmail.com,
	netdev@vger.kernel.org
Subject: Re: [PATCH net] ipv6: fix out of bound writes in __ip6_append_data()
Date: Mon, 22 May 2017 11:48:34 -0400 (EDT)	[thread overview]
Message-ID: <20170522.114834.59066499542253617.davem@davemloft.net> (raw)
In-Reply-To: <1495228668.6465.44.camel@edumazet-glaptop3.roam.corp.google.com>

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 19 May 2017 14:17:48 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> Andrey Konovalov and idaifish@gmail.com reported crashes caused by
> one skb shared_info being overwritten from __ip6_append_data()
> 
> Andrey program lead to following state :
> 
> copy -4200 datalen 2000 fraglen 2040 
> maxfraglen 2040 alloclen 2048 transhdrlen 0 offset 0 fraggap 6200
> 
> The skb_copy_and_csum_bits(skb_prev, maxfraglen, data + transhdrlen,
> fraggap, 0); is overwriting skb->head and skb_shared_info
> 
> Since we apparently detect this rare condition too late, move the
> code earlier to even avoid allocating skb and risking crashes.
> 
> Once again, many thanks to Andrey and syzkaller team.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Andrey Konovalov <andreyknvl@google.com>
> Tested-by: Andrey Konovalov <andreyknvl@google.com>
> Reported-by: <idaifish@gmail.com>

Looks good, applied and queued up for -stable.

Thanks Eric.

      reply	other threads:[~2017-05-22 15:49 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <ebd31eba-3675-474a-a3ea-1d91cd31f2df@googlegroups.com>
2017-05-19 12:57 ` general protection fault in skb_release_data Andrey Konovalov
2017-05-19 14:36   ` Eric Dumazet
2017-05-19 14:50     ` Andrey Konovalov
2017-05-19 21:17       ` [PATCH net] ipv6: fix out of bound writes in __ip6_append_data() Eric Dumazet
2017-05-22 15:48         ` David Miller [this message]

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