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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	netdev@vger.kernel.org
Cc: davem@davemloft.net, edumazet@google.com, jasowang@redhat.com,
	maximmi@mellanox.com, Willem de Bruijn <willemb@google.com>,
	syzbot <syzkaller@googlegroups.com>
Subject: Re: [PATCH net] net: validate untrusted gso packets without csum offload
Date: Fri, 15 Feb 2019 09:36:36 -0800	[thread overview]
Message-ID: <0116d20d-a2ea-e4b8-8aa6-a1c4d0128fc5@gmail.com> (raw)
In-Reply-To: <20190215171547.247018-1-willemdebruijn.kernel@gmail.com>



On 02/15/2019 09:15 AM, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@google.com>
> 
> Syzkaller again found a path to a kernel crash through bad gso input.
> By building an excessively large packet to cause an skb field to wrap.
> 
> If VIRTIO_NET_HDR_F_NEEDS_CSUM was set this would have been dropped in
> skb_partial_csum_set.
> 
> GSO packets that do not set checksum offload are suspicious and rare.
> Most callers of virtio_net_hdr_to_skb already pass them to
> skb_probe_transport_header.
> 
> Move that test forward, change it to detect parse failure and drop
> packets on failure as those cleary are not one of the legitimate
> VIRTIO_NET_HDR_GSO types.
> 
> Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.")
> Fixes: f43798c27684 ("tun: Allow GSO using virtio_net_hdr")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Willem de Bruijn <willemb@google.com>

Reviewed-by: Eric Dumazet <edumazet@google.com>


  reply	other threads:[~2019-02-15 17:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-15 17:15 [PATCH net] net: validate untrusted gso packets without csum offload Willem de Bruijn
2019-02-15 17:36 ` Eric Dumazet [this message]
2019-02-16  4:31 ` David Miller
2019-02-18 19:12 ` Willem de Bruijn
2019-02-19  4:40   ` Willem de Bruijn

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