linux-kernel - Re: [net] ipv6: sr: fix missing sk_buff release in seg6_input

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Message-ID: <20240517192354.GB475595@kernel.org>
Date: Fri, 17 May 2024 20:23:54 +0100
From: Simon Horman <horms@...nel.org>
To: Andrea Mayer <andrea.mayer@...roma2.it>
Cc: "David S. Miller" <davem@...emloft.net>,
	David Ahern <dsahern@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	David Lebrun <david.lebrun@...ouvain.be>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Stefano Salsano <stefano.salsano@...roma2.it>,
	Paolo Lungaroni <paolo.lungaroni@...roma2.it>,
	Ahmed Abdelsalam <ahabdels.dev@...il.com>
Subject: Re: [net] ipv6: sr: fix missing sk_buff release in seg6_input_core

On Fri, May 17, 2024 at 06:45:41PM +0200, Andrea Mayer wrote:
> The seg6_input() function is responsible for adding the SRH into a
> packet, delegating the operation to the seg6_input_core(). This function
> uses the skb_cow_head() to ensure that there is sufficient headroom in
> the sk_buff for accommodating the link-layer header.
> In the event that the skb_cow_header() function fails, the
> seg6_input_core() catches the error but it does not release the sk_buff,
> which will result in a memory leak.
> 
> This issue was introduced in commit af3b5158b89d ("ipv6: sr: fix BUG due
> to headroom too small after SRH push") and persists even after commit
> 7a3f5b0de364 ("netfilter: add netfilter hooks to SRv6 data plane"),
> where the entire seg6_input() code was refactored to deal with netfilter
> hooks.
> 
> The proposed patch addresses the identified memory leak by requiring the
> seg6_input_core() function to release the sk_buff in the event that
> skb_cow_head() fails.
> 
> Fixes: af3b5158b89d ("ipv6: sr: fix BUG due to headroom too small after SRH push")
> Signed-off-by: Andrea Mayer <andrea.mayer@...roma2.it>

Reviewed-by: Simon Horman <horms@...nel.org>