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From:   Alistair Delva <adelva@google.com>
Date:   Mon, 15 Nov 2021 10:17:30 -0800
Message-ID: <CANDihLE5oO2=MDiPtGmUzZgaPuzT2_X7da-vKe+ybBJkXgnsAQ@mail.gmail.com>
Subject: Re: [PATCH] block: Check ADMIN before NICE for IOPRIO_CLASS_RT
To:     Jens Axboe <axboe@kernel.dk>
Cc:     linux-kernel@vger.kernel.org,
        Khazhismel Kumykov <khazhy@google.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Serge Hallyn <serge@hallyn.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Paul Moore <paul@paul-moore.com>, selinux@vger.kernel.org,
        linux-security-module@vger.kernel.org, kernel-team@android.com,
        stable@vger.kernel.org
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On Mon, Nov 15, 2021 at 10:04 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> On 11/15/21 10:38 AM, Alistair Delva wrote:
> > Booting to Android userspace on 5.14 or newer triggers the following
> > SELinux denial:
> >
> > avc: denied { sys_nice } for comm="init" capability=23
> >      scontext=u:r:init:s0 tcontext=u:r:init:s0 tclass=capability
> >      permissive=0
> >
> > Init is PID 0 running as root, so it already has CAP_SYS_ADMIN. For
> > better compatibility with older SEPolicy, check ADMIN before NICE.
>
> Seems a bit wonky to me, but the end result is the same.

No argument from me..

> In any case,
> this warrants a comment above it detailing why the ordering is
> seemingly important.

Sent v2.

> --
> Jens Axboe
>