netdev - Re: [PATCH net] macsec: avoid heap overflow in skb_to

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Message-ID: <20170425155140.GA13414@bistromath.localdomain>
Date:   Tue, 25 Apr 2017 17:51:40 +0200
From:   Sabrina Dubroca <sd@...asysnail.net>
To:     "Jason A. Donenfeld" <Jason@...c4.com>
Cc:     Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net] macsec: avoid heap overflow in skb_to_sgvec on
 receive

2017-04-25, 17:39:09 +0200, Jason A. Donenfeld wrote:
> Hi Sabrina,
> 
> I think I may have beaten you to the punch here by a few minutes. :)

I said I was going to post a patch.
Mail headers seem to disagree with you ;)

> The difference between our two versions is that you don't re-add the
> FRAGLIST attribute, whereas my patch does, and then it does the
> dynamic allocation. I suspect this might be a bit more robust. It also
> ensures that skb_cow_data is called on both paths. So perhaps let's
> roll with mine?

I don't see the "more robust" argument.

Unless I missed something, encrypt was already handling fragments
correctly. An skb with ->frag_list should have no skb_tailroom, so it
will be linearized skb_copy_expand().

-- 
Sabrina