From: Paul Moore <paul@paul-moore.com>
To: Peter Xu <peterx@redhat.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
David Hildenbrand <david@redhat.com>,
Lokesh Gidra <lokeshgidra@google.com>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Robert O'Callahan" <roc@ocallahan.org>
Subject: Re: [RFC PATCH RESEND] userfaultfd: open userfaultfds with O_RDONLY
Date: Tue, 12 Jul 2022 17:16:45 -0400 [thread overview]
Message-ID: <CAHC9VhRv2VPvUAbpDo0D0oK9gEHL=vcOh84M9Fg+AN1c1SR0pA@mail.gmail.com> (raw)
In-Reply-To: <Ys2DobolHlrXP4/M@xz-m1.local>
On Tue, Jul 12, 2022 at 10:22 AM Peter Xu <peterx@redhat.com> wrote:
> On Fri, Jul 08, 2022 at 11:34:51AM +0200, Ondrej Mosnacek wrote:
> > Since userfaultfd doesn't implement a write operation, it is more
> > appropriate to open it read-only.
> >
> > When userfaultfds are opened read-write like it is now, and such fd is
> > passed from one process to another, SELinux will check both read and
> > write permissions for the target process, even though it can't actually
> > do any write operation on the fd later.
> >
> > Inspired by the following bug report, which has hit the SELinux scenario
> > described above:
> > https://bugzilla.redhat.com/show_bug.cgi?id=1974559
> >
> > Reported-by: Robert O'Callahan <roc@ocallahan.org>
> > Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization")
> > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
>
> Acked-by: Peter Xu <peterx@redhat.com>
Thanks Peter.
--
paul-moore.com
next prev parent reply other threads:[~2022-07-12 21:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-08 9:34 Ondrej Mosnacek
2022-07-12 14:22 ` Peter Xu
2022-07-12 21:16 ` Paul Moore [this message]
2022-08-16 22:12 ` Paul Moore
2022-08-19 18:50 ` Paul Moore
2022-08-26 8:43 ` Christian Brauner
2022-08-30 20:10 ` Paul Moore
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