From: Paul Moore <paul@paul-moore.com>
To: Luigi Semenzato <semenzato@google.com>
Cc: linux-security-module@vger.kernel.org
Subject: Re: adding CAP_RESERVED_# bits
Date: Fri, 6 Jun 2025 22:11:21 -0400 [thread overview]
Message-ID: <CAHC9VhT-UKWRbmsuJfkWO6BK_Mon4KUMB8DU5py1gDBJgYwJDw@mail.gmail.com> (raw)
In-Reply-To: <CAA25o9TqH3LNWy8F2tXO7P6AdQk0x+boWiPhy+CKL=wDouKODw@mail.gmail.com>
On Fri, Jun 6, 2025 at 1:58 PM Luigi Semenzato <semenzato@google.com> wrote:
>
> Recently I inquired about the decision process for adding a CAP_DRM
> bit to capability.h (to become DRM master). It occurred to me that
> the process for adding ANY bit would be fraught with controversies (to
> say the least).
>
> So I looked into maintaining a patch in our own kernel sources, but
> that was surprisingly messy due to the build-time dependencies of
> capability.h and the way we maintain and share sources internally for
> multiple kernel versions. This would have been quite simple if there
> were a few reserved bits, such as CAP_RESERVED_0, ..,
> CAP_RESERVED_<N-1> with, say, N=3.
>
> Would this also be controversial?
Yes, and likely rejected too. The upstream Linux kernel generally
doesn't make any sacrifices to support out-of-tree kernel code, and
giving up precious capability bitmap space would definitely be
considered a sacrifice.
--
paul-moore.com
next prev parent reply other threads:[~2025-06-07 2:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-06 17:57 adding CAP_RESERVED_# bits Luigi Semenzato
2025-06-06 18:32 ` Casey Schaufler
2025-06-06 20:11 ` Luigi Semenzato
2025-06-06 20:42 ` Casey Schaufler
2025-06-06 21:49 ` Luigi Semenzato
2025-06-07 2:11 ` Paul Moore [this message]
2025-06-27 20:26 ` Luigi Semenzato
2025-06-28 3:40 ` Serge E. Hallyn
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