netdev - Re: [PATCH] net/xfrm_input: fix possible NULL deref of tunnel.ip6->parms.i

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Message-ID: <20160812071656.GH5710@gauss.secunet.com>
Date:	Fri, 12 Aug 2016 09:16:56 +0200
From:	Steffen Klassert <steffen.klassert@...unet.com>
To:	Alexey Kodanev <alexey.kodanev@...cle.com>
CC:	<netdev@...r.kernel.org>, <vasily.isaenko@...cle.com>
Subject: Re: [PATCH] net/xfrm_input: fix possible NULL deref of
 tunnel.ip6->parms.i_key

On Wed, Aug 10, 2016 at 01:54:57PM +0300, Alexey Kodanev wrote:
> Running LTP 'icmp-uni-basic.sh -6 -p ipcomp -m tunnel' test over
> openvswitch + veth can trigger kernel panic:
> 
>   BUG: unable to handle kernel NULL pointer dereference
>   at 00000000000000e0 IP: [<ffffffff8169d1d2>] xfrm_input+0x82/0x750
>   ...
>   [<ffffffff816d472e>] xfrm6_rcv_spi+0x1e/0x20
>   [<ffffffffa082c3c2>] xfrm6_tunnel_rcv+0x42/0x50 [xfrm6_tunnel]
>   [<ffffffffa082727e>] tunnel6_rcv+0x3e/0x8c [tunnel6]
>   [<ffffffff8169f365>] ip6_input_finish+0xd5/0x430
>   [<ffffffff8169fc53>] ip6_input+0x33/0x90
>   [<ffffffff8169f1d5>] ip6_rcv_finish+0xa5/0xb0
>   ...
> 
> It seems that tunnel.ip6 can have garbage values and also dereferenced
> without a proper check, only tunnel.ip4 is being verified. Fix it by
> adding one more if block for AF_INET6 and initialize tunnel.ip6 with NULL
> inside xfrm6_rcv_spi() (which is similar to xfrm4_rcv_spi()).
> 
> Fixes: 049f8e2 ("xfrm: Override skb->mark with tunnel->parm.i_key in xfrm_input")
> 
> Signed-off-by: Alexey Kodanev <alexey.kodanev@...cle.com>

Applied to the ipsec tree, thanks a lot for the fix!