From: Christian Brauner <christian.brauner@ubuntu.com>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>, Kees Cook <keescook@chromium.org>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Jim Newsome <jnewsome@torproject.org>,
Alexey Gladkov <legion@kernel.org>,
Security Officers <security@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Jann Horn <jannh@google.com>
Subject: Re: [PATCH] exit: Retain nsproxy for exit_task_work() work entries
Date: Thu, 9 Dec 2021 15:08:26 +0100 [thread overview]
Message-ID: <20211209140826.kc2xvvwxrdrwmrtj@wittgenstein> (raw)
In-Reply-To: <20211209134419.GA17186@blackbody.suse.cz>
On Thu, Dec 09, 2021 at 02:44:19PM +0100, Michal Koutný wrote:
> On Wed, Dec 08, 2021 at 01:07:54PM -1000, Tejun Heo <tj@kernel.org> wrote:
>
> > + saved_cred = override_creds(of->file->f_cred);
> > ret = cgroup_attach_permissions(src_cgrp, dst_cgrp,
> > - of->file->f_path.dentry->d_sb, threadgroup);
> > + of->file->f_path.dentry->d_sb,
> > + threadgroup, ctx->ns);
> > + revert_creds(saved_cred);
>
> I wonder now whether such a wrap shouldn't also be around cgroup_kill()
> too (+ replacement of send_sig() with group_send_sig_info() [1])?
send_sig() isn't used that was changed in response to a review. I'm
confused.
>
> This shouldn't break the use case of passing cgroup kill fd to a less
> privileged task for (auto)destruction purposes but on the other hand it
> would prevent subverting the fd to a more privileged confused task to
> kill otherwise disallowed processes.
Kill and freeze only do time permission checking at open. Why would you
introduce another write time check?
next prev parent reply other threads:[~2021-12-09 14:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 18:05 [PATCH] exit: Retain nsproxy for exit_task_work() work entries Michal Koutný
2021-12-08 18:45 ` Eric W. Biederman
2021-12-08 19:06 ` Tejun Heo
2021-12-08 19:39 ` Linus Torvalds
2021-12-08 19:49 ` Tejun Heo
2021-12-08 23:07 ` Tejun Heo
2021-12-09 13:44 ` Michal Koutný
2021-12-09 14:08 ` Christian Brauner [this message]
2021-12-09 14:47 ` Michal Koutný
2021-12-09 15:06 ` Christian Brauner
2021-12-09 16:39 ` Michal Koutný
2021-12-10 23:12 ` Michal Koutný
2021-12-13 15:24 ` Eric W. Biederman
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