From: Florian Westphal <fw@strlen•de>
To: Florent Revest <revest@chromium•org>
Cc: Florian Westphal <fw@strlen•de>,
Pablo Neira Ayuso <pablo@netfilter•org>,
netfilter-devel@vger•kernel.org, coreteam@netfilter•org,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
bpf@vger•kernel.org, kadlec@netfilter•org, davem@davemloft•net,
edumazet@google•com, kuba@kernel•org, pabeni@redhat•com,
lirongqing@baidu•com, daniel@iogearbox•net, ast@kernel•org,
kpsingh@kernel•org, stable@vger•kernel.org
Subject: Re: [PATCH nf] netfilter: conntrack: Avoid nf_ct_helper_hash uses after free
Date: Wed, 21 Jun 2023 20:47:38 +0200 [thread overview]
Message-ID: <20230621184738.GG24035@breakpoint.cc> (raw)
In-Reply-To: <CABRcYmKeo6A+3dmZd9bRp8W3tO9M5cHDpQ13b8aeMkhYr4L64Q@mail.gmail.com>
Florent Revest <revest@chromium•org> wrote:
> > in this case an initcall is failing and I think panic is preferrable
> > to a kernel that behaves like NF_CONNTRACK_FTP=n.
>
> In that case, it seems like what you'd want is
> nf_conntrack_standalone_init() to BUG() instead of returning an error
> then ? (so you'd never get to NF_CONNTRACK_FTP or any other if
> nf_conntrack failed to initialize) If this is the prefered behavior,
> then sure, why not.
>
> > AFAICS this problem is specific to NF_CONNTRACK_FTP=y
> > (or any other helper module, for that matter).
>
> Even with NF_CONNTRACK_FTP=m, the initialization failure in
> nf_conntrack_standalone_init() still happens. Therefore, the helper
> hashtable gets freed and when the nf_conntrack_ftp.ko module gets
> insmod-ed, it calls nf_conntrack_helpers_register() and this still
> causes a use-after-free.
Can you send a v2 with a slightly reworded changelog?
It should mention that one needs NF_CONNTRACK=y, so that when
the failure happens during the initcall (as oposed to module insertion),
nf_conntrack_helpers_register() can fail cleanly without followup splat?
Thanks.
next prev parent reply other threads:[~2023-06-21 18:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-15 15:29 [PATCH nf] netfilter: conntrack: Avoid nf_ct_helper_hash uses after free Florent Revest
2023-06-20 6:35 ` Pablo Neira Ayuso
2023-06-21 10:20 ` Florent Revest
2023-06-21 11:12 ` Pablo Neira Ayuso
2023-06-21 12:41 ` Florent Revest
2023-06-21 11:14 ` Florian Westphal
2023-06-21 13:07 ` Florent Revest
2023-06-21 18:47 ` Florian Westphal [this message]
2023-07-03 14:42 ` Florent Revest
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