From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pablo Neira Ayuso <pablo@netfilter.org>
Subject: Re: [PATCH v2] netfilter: nfnetlink: Improve input length
 sanitization in nfnetlink_rcv
Date: Tue, 27 Jun 2017 17:58:25 +0200
Message-ID: <20170627155825.GA4885@salvia>
References: <1496841821.736.35.camel@edumazet-glaptop3.roam.corp.google.com>
 <20170607135038.1592-1-mjurczyk@google.com>
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Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
        Florian Westphal <fw@strlen.de>,
        "David S. Miller" <davem@davemloft.net>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
To: Mateusz Jurczyk <mjurczyk@google.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
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In-Reply-To: <20170607135038.1592-1-mjurczyk@google.com>
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On Wed, Jun 07, 2017 at 03:50:38PM +0200, Mateusz Jurczyk wrote:
> Verify that the length of the socket buffer is sufficient to cover the
> nlmsghdr structure before accessing the nlh->nlmsg_len field for further
> input sanitization. If the client only supplies 1-3 bytes of data in
> sk_buff, then nlh->nlmsg_len remains partially uninitialized and
> contains leftover memory from the corresponding kernel allocation.
> Operating on such data may result in indeterminate evaluation of the
> nlmsg_len < NLMSG_HDRLEN expression.
> 
> The bug was discovered by a runtime instrumentation designed to detect
> use of uninitialized memory in the kernel. The patch prevents this and
> other similar tools (e.g. KMSAN) from flagging this behavior in the future.

Applied, thanks.