linux-kernel - Re: [PATCH] ipc: don't audit capability check in ipc

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Message-ID: <aXgcd81ktMaAHhwj@mail.hallyn.com>
Date: Mon, 26 Jan 2026 20:01:27 -0600
From: "Serge E. Hallyn" <serge@...lyn.com>
To: Paul Moore <paul@...l-moore.com>
Cc: Ondrej Mosnacek <omosnace@...hat.com>, Serge Hallyn <serge@...lyn.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W . Biederman" <ebiederm@...ssion.com>,
	Alexey Gladkov <legion@...nel.org>, linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org, selinux@...r.kernel.org
Subject: Re: [PATCH] ipc: don't audit capability check in ipc_permissions()

On Mon, Jan 26, 2026 at 05:50:12PM -0500, Paul Moore wrote:
> On Thu, Jan 22, 2026 at 9:56 AM Ondrej Mosnacek <omosnace@...hat.com> wrote:
> >
> > The IPC sysctls implement the ctl_table_root::permissions hook and
> > they override the file access mode based on the CAP_CHECKPOINT_RESTORE
> > capability, which is being checked regardless of whether any access is
> > actually denied or not, so if an LSM denies the capability, an audit
> > record may be logged even when access is in fact granted.
> >
> > It wouldn't be viable to restructure the sysctl permission logic to only
> > check the capability when the access would be actually denied if it's
> > not granted. Thus, do the same as in net_ctl_permissions()
> > (net/sysctl_net.c) - switch from ns_capable() to ns_capable_noaudit(),
> > so that the check never emits an audit record.
> >
> > Fixes: 0889f44e2810 ("ipc: Check permissions for checkpoint_restart sysctls at open time")
> > Signed-off-by: Ondrej Mosnacek <omosnace@...hat.com>
> > ---
> >  include/linux/capability.h | 6 ++++++
> >  ipc/ipc_sysctl.c           | 2 +-
> >  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> This change seems reasonable to me, but I would make sure Serge has a
> chance to review/ACK this patch as it has a capability impact.

Acked-by: Serge Hallyn <serge@...lyn.com>

Thanks - looks good to me.