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Date: Tue, 6 Feb 2024 12:11:12 +0100
From: Florian Westphal <fw@strlen.de>
To: Michal Kubecek <mkubecek@suse.cz>
Cc: Dan Carpenter <dan.carpenter@linaro.org>,
	Florian Westphal <fw@strlen.de>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	Jozsef Kadlecsik <kadlec@netfilter.org>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org, andrea.mattiazzo@suse.com
Subject: Re: [PATCH net] netfilter: nf_tables: fix pointer math issue in
 nft_byteorder_eval()
Message-ID: <20240206111112.GD17626@breakpoint.cc>
References: <15fdceb5-2de5-4453-98b3-cfa9d486e8da@moroto.mountain>
 <20240206104336.ctigqpkunom2ufmn@lion.mk-sys.cz>
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User-Agent: Mutt/1.10.1 (2018-07-13)

Michal Kubecek <mkubecek@suse.cz> wrote:
> I stumbled upon this when the issue got a CVE id (sigh) and I share
> Andrea's (Cc-ed) concern that the fix is incomplete. While the fix,
> commit c301f0981fdd ("netfilter: nf_tables: fix pointer math issue in
> nft_byteorder_eval()") now, fixes the destination side, src is still
> a pointer to u32, i.e. we are reading 64-bit values with relative
> offsets which are multiples of 32 bits.
> 
> Shouldn't we fix this as well, e.g. like indicated below?

No, please remove multi-elem support instead, nothing uses this feature.