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Date: Mon, 15 Jul 2024 13:17:10 -0700
From: Kees Cook <kees@kernel.org>
To: =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@digikod.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, cve@kernel.org,
	linux-kernel@vger.kernel.org,
	=?iso-8859-1?Q?G=FCnther?= Noack <gnoack@google.com>,
	linux-security-module@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: Re: CVE-2024-40938: landlock: Fix d_parent walk
Message-ID: <202407151315.88BE0662@keescook>
References: <2024071218-CVE-2024-40938-1619@gregkh>
 <20240715.aeLiunipi8ia@digikod.net>
 <2024071553-yippee-broadways-8035@gregkh>
 <20240715.Eishohd0ehoo@digikod.net>
 <202407150908.34E00AAD1@keescook>
 <20240715.seingevie9Ph@digikod.net>
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In-Reply-To: <20240715.seingevie9Ph@digikod.net>

On Mon, Jul 15, 2024 at 08:04:21PM +0200, Mickaël Salaün wrote:
> Yes, that's why we use WARN_ON_ONCE() to check cases that should never
> happen (at the time of writting), but in practice it's useful to check
> (with fuzzing) that this assertion is true.  However, if a
> WARN_ON_ONCE() is reached, this doesn't mean that this is a security
> issue, but just an unexpected case that kernel maintainers should be
> notified with to fix it.

I leave CVE determinations to the CNA. :) I think the difficulty here is
with having no way to trivially see which WARN is security sensitive and
which isn't, and since WARNs may panic, all WARNs could be a DoS, and
therefore may be a CVE for some deployment somewhere.

-- 
Kees Cook