netdev - Re: [PATCH net] net: qdisc_pkt_len_init() should be more robust

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Date:   Mon, 22 Jan 2018 16:00:59 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     eric.dumazet@...il.com
Cc:     netdev@...r.kernel.org, willemb@...gle.com, jasowang@...hat.com
Subject: Re: [PATCH net] net: qdisc_pkt_len_init() should be more robust

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Thu, 18 Jan 2018 19:59:19 -0800

> From: Eric Dumazet <edumazet@...gle.com>
> 
> Without proper validation of DODGY packets, we might very well
> feed qdisc_pkt_len_init() with invalid GSO packets.
> 
> tcp_hdrlen() might access out-of-bound data, so let's use
> skb_header_pointer() and proper checks.
> 
> Whole story is described in commit d0c081b49137 ("flow_dissector:
> properly cap thoff field")
> 
> We have the goal of validating DODGY packets earlier in the stack,
> so we might very well revert this fix in the future.
> 
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Cc: Willem de Bruijn <willemb@...gle.com>
> Cc: Jason Wang <jasowang@...hat.com>
> Reported-by: syzbot+9da69ebac7dddd804552@...kaller.appspotmail.com

Applied and queued up for -stable, thanks Eric.