From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-bc09.mail.infomaniak.ch (smtp-bc09.mail.infomaniak.ch [45.157.188.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 62368189F5C for ; Mon, 15 Jul 2024 12:21:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.157.188.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721046074; cv=none; b=E1ULlFPVi/Y085YR857vDsPeRMmkkZ2/r0iBHE5oDRRRwSX9pc1aLZEU9j9ZYEO1nDTiVNR8q+BIX/I913r1MJgQR2haayPZCdMmc9ThjzVvu77yBMVK1n9D2SybwILFDVLAIA1EA+qL46G1oeXgP1PwVa8xx2sDwr1r0KJexWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721046074; c=relaxed/simple; bh=qLeSM8yy9Pm45fo+A7K1Jltke1y6CtzYxPtAFqAQmWM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M7Xl7ZJq3d3zi7K9oYWgaA0NWRGBiKgOVnW4Q3CpwmM29YpnOVJ6Wupz/IEdr90xEmL57d0wsurbJ5guSfsua8aLi3xkba3XAzeZSetlVZM7NNksXe8SV4p6NC6kz1kpSC/i1Uh26+diI33RxJM3fNKb0s5ir1yo/jDFM2qp4iY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net; spf=pass smtp.mailfrom=digikod.net; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b=J+TUa4ey; arc=none smtp.client-ip=45.157.188.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=digikod.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b="J+TUa4ey" Received: from smtp-4-0000.mail.infomaniak.ch (smtp-4-0000.mail.infomaniak.ch [10.7.10.107]) by smtp-4-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4WN1Wd40wKzgCQ; Mon, 15 Jul 2024 14:21:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digikod.net; s=20191114; t=1721046061; bh=sTqWvowT9CGlN8d5YXZBulF2bbw/PtMqLh9miq/PfrA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=J+TUa4eypLG7kr9QeXVxab92+lL1eTU2yn3O/0spQ6YkXSLqrDVQ/P7+6fktYUqBE wLPCmKdFqsL3KZ5WujJsdro8mFLLaM85FrxFGGSo/hdzWThflw1ZzMT5AjH8O9F8T2 UVoiXHxXzH8UHKQXWKhmANsBLiVu+99X3KOMqIbE= Received: from unknown by smtp-4-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4WN1Wc6TYhzwYx; Mon, 15 Jul 2024 14:21:00 +0200 (CEST) Date: Mon, 15 Jul 2024 14:20:59 +0200 From: =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= To: Greg Kroah-Hartman Cc: cve@kernel.org, linux-kernel@vger.kernel.org, =?utf-8?Q?G=C3=BCnther?= Noack , linux-security-module@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: CVE-2024-40938: landlock: Fix d_parent walk Message-ID: <20240715.Eishohd0ehoo@digikod.net> References: <2024071218-CVE-2024-40938-1619@gregkh> <20240715.aeLiunipi8ia@digikod.net> <2024071553-yippee-broadways-8035@gregkh> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2024071553-yippee-broadways-8035@gregkh> X-Infomaniak-Routing: alpha On Mon, Jul 15, 2024 at 01:16:38PM +0200, Greg Kroah-Hartman wrote: > On Mon, Jul 15, 2024 at 12:37:53PM +0200, Mickaël Salaün wrote: > > Hello, > > > > AFAIK, commit 88da52ccd66e ("landlock: Fix d_parent walk") doesn't fix a > > security issue but an unexpected case. The triggered WARN_ON_ONCE() is > > just a canary, and this case was correctly handled with defensive > > programming and didn't allow to bypass the security policy nor to harm > > the kernel. However, this fix should indeed be backported. > > If a WARN_ON() is hit, a machine with panic_on_warn enabled will reboot, > hence if there is any way that userspace can hit this, it needs to be > issued a CVE, sorry. OK, I didn't know about this panic_on_warn rule for CVE. Out of curiosity, panic_on_warn is definitely useful for fuzzing and testing, but what is the rational to enable panic_on_warn on production systems? It literally transforms a warning message into a system DoS (i.e. WARN_ON into BUG_ON). We should explicitly use BUG_ON() if this is a critical unhandled case, right? > > > Could you please Cc me for future CVE related to my changes or to > > Landlock? For kernel CVEs, I think it would be good to Cc at least > > maintainers, reviewers, authors, and committers for the related commits. > > I suggest setting up lei to watch the linux-cve-announce mailing list if > you wish to do this (just filter for landlock stuff). Automatically > mailing cve stuff to maintainers has been deemed too "noisy" which is > why we do not do this by default. Well, it might be too noisy for some but I guess/hope not for most. Email filtering should be easy for the few receiving too many of these emails though.