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From: Florian Westphal <>
To: Pavel Skripkin <>
Subject: Re: [PATCH v2] netfilter: protect nft_ct_pcpu_template_refcnt with mutex
Date: Tue, 10 Aug 2021 15:22:48 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Pavel Skripkin <> wrote:
> Syzbot hit use-after-free in nf_tables_dump_sets. The problem was in
> missing lock protection for nft_ct_pcpu_template_refcnt.
> Before commit f102d66b335a ("netfilter: nf_tables: use dedicated
> mutex to guard transactions") all transactions were serialized by global
> mutex, but then global mutex was changed to local per netnamespace
> commit_mutex.
> This change causes use-after-free bug, when 2 netnamespaces concurently
> changing nft_ct_pcpu_template_refcnt without proper locking. Fix it by
> adding nft_ct_pcpu_mutex and protect all nft_ct_pcpu_template_refcnt
> changes with it.
> Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions")
> Reported-and-tested-by:
> Signed-off-by: Pavel Skripkin <>

Acked-by: Florian Westphal <>

  reply	other threads:[~2021-08-10 13:23 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10 12:55 [PATCH] netfiler: " Pavel Skripkin
2021-08-10 12:59 ` [PATCH v2] netfilter: " Pavel Skripkin
2021-08-10 13:22   ` Florian Westphal [this message]
2021-08-11  9:22   ` Pablo Neira Ayuso

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