From: Florian Westphal <fw@strlen.de>
To: Quan Tian <tianquan23@gmail.com>
Cc: Florian Westphal <fw@strlen.de>,
Pablo Neira Ayuso <pablo@netfilter.org>,
netfilter-devel@vger.kernel.org, kadlec@netfilter.org
Subject: Re: [PATCH v3 nf-next 2/2] netfilter: nf_tables: support updating userdata for nft_table
Date: Tue, 12 Mar 2024 15:33:00 +0100 [thread overview]
Message-ID: <20240312143300.GF1529@breakpoint.cc> (raw)
In-Reply-To: <ZfBmCbGamurxXE5U@ubuntu-1-2>
Quan Tian <tianquan23@gmail.com> wrote:
> In nf_tables_commit():
> The 1st trans swaps old udata with 1st new udata;
> The 2nd trans swaps 1st new udata with 2nd new udata.
>
> In nft_commit_release():
> The 1st trans frees old udata;
> The 2nd trans frees 1st new udata.
>
> So multiple udata requests in a batch could work?
Yes, it could work indeed but we got bitten by
subtle bugs with back-to-back updates.
If there is a simple way to detect and reject
this then I believe its better to disallow it.
Unless you come up with a use-case where such back-to-back
udate updates make sense of course.
next prev parent reply other threads:[~2024-03-12 14:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-11 14:14 [PATCH v3 nf-next 1/2] netfilter: nf_tables: use struct nlattr * to store userdata for nft_table Quan Tian
2024-03-11 14:14 ` [PATCH v3 nf-next 2/2] netfilter: nf_tables: support updating " Quan Tian
2024-03-12 12:27 ` Florian Westphal
2024-03-12 12:49 ` Pablo Neira Ayuso
2024-03-12 13:01 ` Florian Westphal
2024-03-12 14:26 ` Quan Tian
2024-03-12 14:33 ` Florian Westphal [this message]
2024-03-12 22:23 ` Pablo Neira Ayuso
2024-03-13 1:35 ` Quan Tian
2024-03-13 9:40 ` Pablo Neira Ayuso
2024-03-13 17:08 ` Quan Tian
2024-03-12 14:36 ` Pablo Neira Ayuso
2024-03-12 13:49 ` Pablo Neira Ayuso
2024-03-12 14:02 ` Florian Westphal
2024-03-12 14:10 ` Florian Westphal
2024-03-12 14:30 ` Quan Tian
2024-03-12 14:05 ` [PATCH v3 nf-next 1/2] netfilter: nf_tables: use struct nlattr * to store " Florian Westphal
2024-03-12 14:17 ` Pablo Neira Ayuso
2024-03-12 14:34 ` Florian Westphal
2024-03-12 15:03 ` Quan Tian
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