From: Aleksa Sarai <cyphar@cyphar.com>
To: Christian Brauner <christian@brauner.io>
Cc: ebiederm@xmission.com, linux-kernel@vger.kernel.org,
serge@hallyn.com, jannh@google.com, luto@kernel.org,
akpm@linux-foundation.org, oleg@redhat.com,
viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, dancol@google.com,
timmurray@google.com, linux-man@vger.kernel.org,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v1 2/2] signal: add procfd_signal() syscall
Date: Tue, 20 Nov 2018 07:28:57 +1100 [thread overview]
Message-ID: <20181119202857.k5zw742xjfrw677j@yavin> (raw)
In-Reply-To: <20181119103241.5229-3-christian@brauner.io>
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On 2018-11-19, Christian Brauner <christian@brauner.io> wrote:
> + if (info) {
> + ret = __copy_siginfo_from_user(sig, &kinfo, info);
> + if (unlikely(ret))
> + goto err;
> + /*
> + * Not even root can pretend to send signals from the kernel.
> + * Nor can they impersonate a kill()/tgkill(), which adds
> + * source info.
> + */
> + ret = -EPERM;
> + if ((kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL) &&
> + (task_pid(current) != pid))
> + goto err;
> + } else {
> + prepare_kill_siginfo(sig, &kinfo);
> + }
I wonder whether we should also have a pidns restriction here, since
currently it isn't possible for a container process using a pidns to
signal processes outside its pidns. AFAICS, this isn't done through an
explicit check -- it's a side-effect of processes in a pidns not being
able to address non-descendant-pidns processes.
But maybe it's reasonable to allow sending a procfd to a different pidns
and the same operations working on it? If we extend the procfd API to
allow process creation this would allow a container to create a process
outside its pidns.
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
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next prev parent reply other threads:[~2018-11-19 20:29 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 10:32 [PATCH v1 0/2] proc: allow signaling processes via file descriptors Christian Brauner
2018-11-19 10:32 ` [PATCH v1 1/2] proc: get process file descriptor from /proc/<pid> Christian Brauner
2018-11-19 15:32 ` Andy Lutomirski
2018-11-19 18:20 ` Christian Brauner
2018-11-19 10:32 ` [PATCH v1 2/2] signal: add procfd_signal() syscall Christian Brauner
2018-11-19 15:45 ` Andy Lutomirski
2018-11-19 15:57 ` Daniel Colascione
2018-11-19 18:39 ` Christian Brauner
2018-11-19 15:59 ` Daniel Colascione
2018-11-19 18:29 ` Christian Brauner
2018-11-19 19:02 ` Eric W. Biederman
2018-11-19 19:31 ` Christian Brauner
2018-11-19 19:39 ` Daniel Colascione
2018-11-19 17:10 ` Eugene Syromiatnikov
2018-11-19 18:23 ` Christian Brauner
2018-11-19 17:14 ` Eugene Syromiatnikov
2018-11-19 20:28 ` Aleksa Sarai [this message]
2018-11-19 20:55 ` Christian Brauner
2018-11-19 21:13 ` Christian Brauner
2018-11-19 21:18 ` Aleksa Sarai
2018-11-19 21:20 ` Christian Brauner
2018-11-19 21:21 ` Christian Brauner
2018-11-19 21:25 ` Aleksa Sarai
2018-11-19 21:26 ` Daniel Colascione
2018-11-19 21:36 ` Aleksa Sarai
2018-11-19 21:37 ` Christian Brauner
2018-11-19 21:41 ` Daniel Colascione
2018-11-20 4:59 ` Eric W. Biederman
2018-11-20 10:31 ` Christian Brauner
2018-11-21 21:39 ` Serge E. Hallyn
2018-11-19 21:23 ` Aleksa Sarai
2018-11-22 7:41 ` Serge E. Hallyn
2018-11-19 22:39 ` Tycho Andersen
2018-11-19 22:49 ` Daniel Colascione
2018-11-19 23:07 ` Tycho Andersen
2018-11-20 0:27 ` Andy Lutomirski
2018-11-20 0:32 ` Christian Brauner
2018-11-20 0:34 ` Andy Lutomirski
2018-11-20 0:49 ` Daniel Colascione
2018-11-22 7:48 ` Serge E. Hallyn
2018-11-19 23:35 ` kbuild test robot
2018-11-19 23:37 ` kbuild test robot
2018-11-19 23:45 ` Christian Brauner
2018-11-28 21:45 ` Joey Pabalinas
2018-11-28 22:05 ` Christian Brauner
2018-11-28 23:02 ` Joey Pabalinas
2018-11-19 10:32 ` [PATCH] procfd_signal.2: document procfd_signal syscall Christian Brauner
2018-11-20 13:29 ` Michael Kerrisk (man-pages)
2018-11-28 20:59 ` Florian Weimer
2018-11-28 21:12 ` Christian Brauner
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