From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: mtk.manpages@gmail.com, Tycho Andersen <tycho@tycho.pizza>,
Sargun Dhillon <sargun@sargun.me>,
Christian Brauner <christian@brauner.io>,
linux-man <linux-man@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
Aleksa Sarai <cyphar@cyphar.com>, Jann Horn <jannh@google.com>,
Alexei Starovoitov <ast@kernel.org>,
wad@chromium.org, bpf@vger.kernel.org,
Song Liu <songliubraving@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Andy Lutomirski <luto@amacapital.net>,
Linux Containers <containers@lists.linux-foundation.org>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Robert Sesek <rsesek@google.com>
Subject: Re: For review: seccomp_user_notif(2) manual page
Date: Thu, 15 Oct 2020 13:24:03 +0200 [thread overview]
Message-ID: <c1cc0df8-bd06-51e7-d5a0-888c1955683b@gmail.com> (raw)
In-Reply-To: <202009301632.9C6A850272@keescook>
Hello Kees,
On 10/1/20 1:39 AM, Kees Cook wrote:
> On Wed, Sep 30, 2020 at 01:07:38PM +0200, Michael Kerrisk (man-pages) wrote:
>> [...] I did :-)
>
> Yay! Thank you!
You're welcome :-)
>> [...]
>> Overview
>> In conventional usage of a seccomp filter, the decision about how
>> to treat a particular system call is made by the filter itself.
>> The user-space notification mechanism allows the handling of the
>> system call to instead be handed off to a user-space process.
>> The advantages of doing this are that, by contrast with the sec‐
>> comp filter, which is running on a virtual machine inside the
>> kernel, the user-space process has access to information that is
>> unavailable to the seccomp filter and it can perform actions that
>> can't be performed from the seccomp filter.
>
> I might clarify a bit with something like (though maybe the
> target/supervisor paragraph needs to be moved to the start):
>
> This is used for performing syscalls on behalf of the target,
> rather than having the supervisor make security policy decisions
> about the syscall, which would be inherently race-prone. The
> target's syscall should either be handled by the supervisor or
> allowed to continue normally in the kernel (where standard security
> policies will be applied).
You, Christian, and Jann all pulled me up on this point. And thanks;
I'm going to use some of your words above. See my reply to Jann, sent
at about the same time as this reply. Please take a look at the text
in my reply to Jann, and let me know what you think.
> I'll comment more later, but I've run out of time today and I didn't see
> anyone mention this detail yet in the existing threads... :)
Later never came :-). But, I hope you may have comments for the
next draft, which I will send out soon.
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
next prev parent reply other threads:[~2020-10-15 11:34 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 11:07 For review: seccomp_user_notif(2) manual page Michael Kerrisk (man-pages)
2020-09-30 15:03 ` Tycho Andersen
2020-09-30 15:11 ` Tycho Andersen
2020-09-30 20:34 ` Michael Kerrisk (man-pages)
2020-09-30 23:03 ` Tycho Andersen
2020-09-30 23:11 ` Jann Horn
2020-09-30 23:24 ` Tycho Andersen
2020-10-01 1:52 ` Jann Horn
2020-10-01 2:14 ` Jann Horn
2020-10-25 16:31 ` Michael Kerrisk (man-pages)
2020-10-26 15:54 ` Jann Horn
2020-10-27 6:14 ` Michael Kerrisk (man-pages)
2020-10-27 10:28 ` Jann Horn
2020-10-28 6:31 ` Sargun Dhillon
2020-10-28 9:43 ` Jann Horn
2020-10-28 17:43 ` Sargun Dhillon
2020-10-28 18:20 ` Jann Horn
2020-10-01 7:49 ` Michael Kerrisk (man-pages)
2020-10-26 0:32 ` Kees Cook
2020-10-26 9:51 ` Jann Horn
2020-10-26 10:31 ` Jann Horn
2020-10-28 22:56 ` Kees Cook
2020-10-29 1:11 ` Jann Horn
[not found] ` <20201029021348.GB25673@cisco>
2020-10-29 4:26 ` Jann Horn
2020-10-28 22:53 ` Kees Cook
2020-10-29 1:25 ` Jann Horn
2020-10-01 7:45 ` Michael Kerrisk (man-pages)
2020-10-14 4:40 ` Michael Kerrisk (man-pages)
2020-09-30 15:53 ` Jann Horn
2020-10-01 12:54 ` Christian Brauner
2020-10-01 15:47 ` Jann Horn
2020-10-01 16:58 ` Tycho Andersen
2020-10-01 17:12 ` Christian Brauner
2020-10-14 5:41 ` Michael Kerrisk (man-pages)
2020-10-01 18:18 ` Jann Horn
2020-10-01 18:56 ` Tycho Andersen
2020-10-01 17:05 ` Christian Brauner
2020-10-15 11:24 ` Michael Kerrisk (man-pages)
2020-10-15 20:32 ` Jann Horn
2020-10-16 18:29 ` Michael Kerrisk (man-pages)
2020-10-17 0:25 ` Jann Horn
2020-10-24 12:52 ` Michael Kerrisk (man-pages)
2020-10-26 9:32 ` Jann Horn
2020-10-26 9:47 ` Michael Kerrisk (man-pages)
2020-09-30 23:39 ` Kees Cook
2020-10-15 11:24 ` Michael Kerrisk (man-pages) [this message]
2020-10-26 0:19 ` Kees Cook
2020-10-26 9:39 ` Michael Kerrisk (man-pages)
2020-10-01 12:36 ` Christian Brauner
2020-10-15 11:23 ` Michael Kerrisk (man-pages)
2020-10-01 21:06 ` Sargun Dhillon
2020-10-01 23:19 ` Tycho Andersen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c1cc0df8-bd06-51e7-d5a0-888c1955683b@gmail.com \
--to=mtk.manpages@gmail.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=christian@brauner.io \
--cc=containers@lists.linux-foundation.org \
--cc=cyphar@cyphar.com \
--cc=daniel@iogearbox.net \
--cc=gscrivan@redhat.com \
--cc=jannh@google.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-man@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=rsesek@google.com \
--cc=sargun@sargun.me \
--cc=songliubraving@fb.com \
--cc=tycho@tycho.pizza \
--cc=wad@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).