netdev - Re: [PATCH] netfilter: fix percpu counter block leak on error path when creating new netns

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Message-ID: <Y/VS7okXF1c6rN/I@salvia>
Date:   Wed, 22 Feb 2023 00:25:34 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Pavel Tikhomirov <ptikhomirov@...tuozzo.com>
Cc:     Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...nvz.org
Subject: Re: [PATCH] netfilter: fix percpu counter block leak on error path
 when creating new netns

Hi,

On Mon, Feb 13, 2023 at 12:25:05PM +0800, Pavel Tikhomirov wrote:
> Here is the stack where we allocate percpu counter block:
> 
>   +-< __alloc_percpu
>     +-< xt_percpu_counter_alloc
>       +-< find_check_entry # {arp,ip,ip6}_tables.c
>         +-< translate_table
> 
> And it can be leaked on this code path:
> 
>   +-> ip6t_register_table
>     +-> translate_table # allocates percpu counter block
>     +-> xt_register_table # fails
> 
> there is no freeing of the counter block on xt_register_table fail.
> Note: xt_percpu_counter_free should be called to free it like we do in
> do_replace through cleanup_entry helper (or in __ip6t_unregister_table).
> 
> Probability of hitting this error path is low AFAICS (xt_register_table
> can only return ENOMEM here, as it is not replacing anything, as we are
> creating new netns, and it is hard to imagine that all previous
> allocations succeeded and after that one in xt_register_table failed).
> But it's worth fixing even the rare leak.

Any suggestion as Fixes: tag here? This issue seems to be rather old?