netdev - Re: [PATCH] netfilter: nfnetlink

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Message-ID: <1794f439-684a-b2ca-2b89-a15c6b6dcd30@embeddedor.com>
Date:   Wed, 21 Mar 2018 08:51:26 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>
Cc:     Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        Kees Cook <keescook@...omium.org>,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: Re: [PATCH] netfilter: nfnetlink_cthelper: Remove VLA usage



On 03/20/2018 07:36 AM, Pablo Neira Ayuso wrote:
> On Mon, Mar 12, 2018 at 07:21:38PM -0500, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wvla, remove VLA and replace it
>> with dynamic memory allocation.
>>
>>  From a security viewpoint, the use of Variable Length Arrays can be
>> a vector for stack overflow attacks. Also, in general, as the code
>> evolves it is easy to lose track of how big a VLA can get. Thus, we
>> can end up having segfaults that are hard to debug.
>>
>> Also, fixed as part of the directive to remove all VLAs from
>> the kernel: https://lkml.org/lkml/2018/3/7/621
> 
> also applied, thanks.
> 

Awesome.

Thanks, Pablo.
--
Gustavo