linux-kernel - Re: [PATCH v2 01/11] coccinelle: Add script to reorder capable() calls

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Message-ID: <174226639139.1025346.1787648992312533082.b4-ty@mit.edu>
Date: Mon, 17 Mar 2025 23:41:14 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Christian Göttsche <cgoettsche@...tendoof.de>
Cc: "Theodore Ts'o" <tytso@....edu>,
        Christian Göttsche <cgzones@...glemail.com>,
        Serge Hallyn <serge@...lyn.com>, Jan Kara <jack@...e.com>,
        Julia Lawall <Julia.Lawall@...ia.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>, linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org, cocci@...ia.fr
Subject: Re: [PATCH v2 01/11] coccinelle: Add script to reorder capable() calls


On Sun, 02 Mar 2025 17:06:48 +0100, Christian Göttsche wrote:
> capable() calls refer to enabled LSMs whether to permit or deny the
> request.  This is relevant in connection with SELinux, where a
> capability check results in a policy decision and by default a denial
> message on insufficient permission is issued.
> It can lead to three undesired cases:
>   1. A denial message is generated, even in case the operation was an
>      unprivileged one and thus the syscall succeeded, creating noise.
>   2. To avoid the noise from 1. the policy writer adds a rule to ignore
>      those denial messages, hiding future syscalls, where the task
>      performs an actual privileged operation, leading to hidden limited
>      functionality of that task.
>   3. To avoid the noise from 1. the policy writer adds a rule to permit
>      the task the requested capability, while it does not need it,
>      violating the principle of least privilege.
> 
> [...]

Applied, thanks!

[03/11] ext4: reorder capability check last
        commit: 26f5784d44c3f824c864245b506db809b51053cf

Best regards,
-- 
Theodore Ts'o <tytso@....edu>