netdev - Re: [PATCH net 2/3] net/sched: act_ipt: add sanity checks on skb before calling target

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Message-ID: <ZIGxIWNUsCDg0J0U@corigine.com>
Date: Thu, 8 Jun 2023 12:44:49 +0200
From: Simon Horman <simon.horman@...igine.com>
To: Florian Westphal <fw@...len.de>
Cc: netdev@...r.kernel.org, jhs@...atatu.com, xiyou.wangcong@...il.com,
	jiri@...nulli.us
Subject: Re: [PATCH net 2/3] net/sched: act_ipt: add sanity checks on skb
 before calling target

On Wed, Jun 07, 2023 at 04:59:53PM +0200, Florian Westphal wrote:
> Netfilter targets make assumptions on the skb state, for example
> iphdr is supposed to be in the linear area.
> 
> This is normally done by IP stack, but in act_ipt case no
> such checks are made.
> 
> Some targets can even assume that skb_dst will be valid.
> Make a minimum effort to check for this:
> 
> - Don't call the targets eval function for non-ipv4 skbs.
> - Don't call the targets eval function for POSTROUTING
>   emulation when the skb has no dst set.
> 
> Signed-off-by: Florian Westphal <fw@...len.de>

Reviewed-by: Simon Horman <simon.horman@...igine.com>