From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DA584522A; Sat, 22 Mar 2025 21:25:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742678702; cv=none; b=gpLUTCZnfyIt6lreaA3ksrXd/n55iY6WhCls8nPRxlZBifAzjVfI1qqEpM4JtoZ5NGOprE1QAVOG0vppp/OH4BaKpC0jK/ug8gNGYjlFCfvMwTdJGRG91u4KQWSC+m7vkoUZPa7MtsgzH73f0DEEFxQ7DjHSfXFJAZTp+YUdzLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742678702; c=relaxed/simple; bh=iXfQco7kSe8vhMA9nzpstt2Zcp6VqukJOUYA5gnQp/0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=htEAYzqREih1bU+lR/lyoYRVNQLWLaIwyTVppv6XxHFJRAQ6M9birzhh1jsjsrkh8pA0BD1mT6FoX+kn99ph9WavKI82DwoTptxbIq+Mb3NLulpgaylAAkncZBJJxgjsTA3dgWmiX23n2e+v9LF5+3Zufmjon9U5rx1XyWdqTpY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n63KfsxJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="n63KfsxJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9076C4CEDD; Sat, 22 Mar 2025 21:25:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742678701; bh=iXfQco7kSe8vhMA9nzpstt2Zcp6VqukJOUYA5gnQp/0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n63KfsxJoK5AsxCVKgpH+MR7lM0aQCdxbL3zoo3tAfiFXXO8yIp6ZrP+Cmka8UzRd OXX13BuQkA3pp4MwCwe2s0C6T7Bi3FQ708Kb+xc3tuREkvsgbgU0mxfzMZUmLAl/ae 5BJmqCLyFNoeSCpI4tGJldykmCwIFbXtxL7WRuYLPBkqnuvGhwcgtcpaQh5VQP32Kh h6Sx+kav/D5ZbqpseJc40naSmAh90JfbyWfuTPqgQfbX69jPzTseONEF6buJFqhiOb +rZ1ljIYrd2OEAdk2RbT+kurrb1lC0rBVEdtvaJ8Aokg9F51g2vUWwA0kX8B37eGR0 /vQWX/JDlArPA== Date: Sat, 22 Mar 2025 23:24:57 +0200 From: Jarkko Sakkinen To: Lennart Poettering Cc: lee joey , Mimi Zohar , Roberto Sassu , Dmitry Kasatkin , Eric Snowberg , Paul Moore , James Morris , "Serge E. Hallyn" , linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, joeyli Subject: Re: [PATCH] Revert "integrity: Do not load MOK and MOKx when secure boot be disabled" Message-ID: References: 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: On Fri, Mar 21, 2025 at 09:39:55AM +0100, Lennart Poettering wrote: > On Fr, 21.03.25 15:13, lee joey (joeyli.kernel@gmail.com) wrote: > > > Hi Lennart, > > > > Lennart Poettering 於 2025年3月20日 週四 下午8:02寫道： > > > > > > This reverts commit 92ad19559ea9a8ec6f158480934ae26ebfe2c14f. > > > > > > This original commit this reverts creates a strange situation: it > > > ensures more restrictive behaviour if SecureBoot is off then when it > > > is on, which is the opposite of what one would expect. > > > > > > Typically, one would expect that if SB is off the validation of > > > resources during the pre-kernel and kernel initialization is less > > > restrictive, not more restrictive. But this check turned the world on > > > its head. > > > > > > > SB off means that the chain of trust is broken. Which means that all > > mechanisms rely on SB are non-secure. Meanwhile, if the integrity of kernel > > can be guaranteed by other mechanism (e.g. TPM), then mok should not > > be loaded when SB off. > > Why not? as you say, chain of trust is broken: the kernel itself is > not immediately integrity protected and neither is the firmware. Hence > filtering out keys in this case is really pointless. The way I look at this is that unless there is an actual threat scenario that we protect against by hiding MOK keys, then we should not hide those keys. Since I don't find any threat scenarios my reviewed-by holds. Pointless checks is security by obfuscation, which is not really security. BR, Jarkko