From: Tom Hromatka <tom.hromatka-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
To: netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
sargun-GaZTRHToo+CzQB+pC5nmwQ@public.gmane.org
Cc: wad-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
daniel-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
ast-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org
Subject: Re: [PATCH net-next 0/3] eBPF Seccomp filters
Date: Tue, 13 Feb 2018 13:33:44 -0700 [thread overview]
Message-ID: <7eb1497e-e5f3-c5ba-e255-7f510795b51d@oracle.com> (raw)
On Tue, Feb 13, 2018 at 7:42 AM, Sargun Dhillon <sargun-GaZTRHToo+CzQB+pC5nmwQ@public.gmane.org> wrote:
> This patchset enables seccomp filters to be written in eBPF. Although,
> this patchset doesn't introduce much of the functionality enabled by
> eBPF, it lays the ground work for it.
>
> It also introduces the capability to dump eBPF filters via the PTRACE
> API in order to make it so that CHECKPOINT_RESTORE will be satisifed.
> In the attached samples, there's an example of this. One can then use
> BPF_OBJ_GET_INFO_BY_FD in order to get the actual code of the program,
> and use that at reload time.
>
> The primary reason for not adding maps support in this patchset is
> to avoid introducing new complexities around PR_SET_NO_NEW_PRIVS.
> If we have a map that the BPF program can read, it can potentially
> "change" privileges after running. It seems like doing writes only
> is safe, because it can be pure, and side effect free, and therefore
> not negatively effect PR_SET_NO_NEW_PRIVS. Nonetheless, if we come
> to an agreement, this can be in a follow-up patchset.
Coincidentally I also sent an RFC for adding eBPF hash maps to the seccomp
userspace mailing list just last week:
https://groups.google.com/forum/#!topic/libseccomp/pX6QkVF0F74
The kernel changes I proposed are in this email:
https://groups.google.com/d/msg/libseccomp/pX6QkVF0F74/ZUJlwI5qAwAJ
In that email thread, Kees requested that I try out a binary tree in cBPF
and evaluate its performance. I just got a rough prototype working, and
while not as fast as an eBPF hash map, the cBPF binary tree was a significant
improvement over the linear list of ifs that are currently generated. Also,
it only required changing a single function within the libseccomp libary
itself.
https://github.com/drakenclimber/libseccomp/commit/87b36369f17385f5a7a4d95101185577fbf6203b
Here are the results I am currently seeing using an in-house customer's
seccomp filter and a simplistic test program that runs getppid() thousands
of times.
Test Case minimum TSC ticks to make syscall
----------------------------------------------------------------
seccomp disabled 620
getppid() at the front of 306-syscall seccomp filter 722
getppid() in middle of 306-syscall seccomp filter 1392
getppid() at the end of the 306-syscall filter 2452
seccomp using a 306-syscall-sized EBPF hash map 800
cBPF filter using a binary tree 922
Thanks.
Tom
next reply other threads:[~2018-02-13 20:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-13 20:33 Tom Hromatka [this message]
[not found] ` <7eb1497e-e5f3-c5ba-e255-7f510795b51d-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2018-02-13 20:35 ` [PATCH net-next 0/3] eBPF Seccomp filters Kees Cook
[not found] ` <CAGXu5jJZgrgLrhkZO33RNdOds8zwnnOZh+rqwguxJM+zm=EJ7g@mail.gmail.com>
[not found] ` <CAGXu5jJZgrgLrhkZO33RNdOds8zwnnOZh+rqwguxJM+zm=EJ7g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 20:38 ` Tom Hromatka
[not found] <20180213154244.GA3292@ircssh-2.c.rugged-nimbus-611.internal>
[not found] ` <20180213154244.GA3292-du9IEJ8oIxHXYT48pCVpJ3c7ZZ+wIVaZYkHkVr5ML8kVGlcevz2xqA@public.gmane.org>
2018-02-13 15:47 ` Kees Cook
2018-02-14 0:47 ` Mickaël Salaün
[not found] ` <CAGXu5jLiYh0rSRuJ_-2xLB03Wod5G07njpoESR4SnmsmiUnsEw@mail.gmail.com>
[not found] ` <CAMp4zn8VNurTjmrUtHnaK21A4hUQQz5tnarj15vmTU+TjY79XA@mail.gmail.com>
[not found] ` <CAMp4zn8VNurTjmrUtHnaK21A4hUQQz5tnarj15vmTU+TjY79XA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 17:02 ` Jessie Frazelle
[not found] ` <CAEk6tEw3ty0kBH+06TYt4=Ywt-4_cHBa9f8p3ajMghtjRkHmMg@mail.gmail.com>
[not found] ` <CAEk6tEw3ty0kBH+06TYt4=Ywt-4_cHBa9f8p3ajMghtjRkHmMg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 17:07 ` Brian Goff
2018-02-13 17:31 ` Sargun Dhillon
[not found] ` <CAMp4zn-Lw0grNrCyjHJZUje1Aznaj03iAUWZ86ki68MZMN1-zA@mail.gmail.com>
[not found] ` <CAMp4zn-Lw0grNrCyjHJZUje1Aznaj03iAUWZ86ki68MZMN1-zA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 20:16 ` Kees Cook
[not found] ` <CAGXu5jKv3QFVKLhok1JWiPamE0b4CqLTO-hx8sP0KWED921=6w@mail.gmail.com>
[not found] ` <CAGXu5jKv3QFVKLhok1JWiPamE0b4CqLTO-hx8sP0KWED921=6w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 20:50 ` Tycho Andersen
2018-02-13 21:08 ` Paul Moore
[not found] ` <CAGXu5jLiYh0rSRuJ_-2xLB03Wod5G07njpoESR4SnmsmiUnsEw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-13 16:29 ` Sargun Dhillon
2018-02-14 17:25 ` Andy Lutomirski
[not found] ` <CALCETrV9xUd3XRgobTDgVNRFY_+o=pEDkfjvuxQ7w_UyH324zA@mail.gmail.com>
[not found] ` <CALCETrV9xUd3XRgobTDgVNRFY_+o=pEDkfjvuxQ7w_UyH324zA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-02-14 17:32 ` Tycho Andersen
[not found] ` <20180214173222.kvos6izqcywkuyi5@cisco>
2018-02-15 4:30 ` Alexei Starovoitov
[not found] ` <20180215043027.zssmhvfdn7iz3rlz@ast-mbp.dhcp.thefacebook.com>
[not found] ` <20180215043027.zssmhvfdn7iz3rlz-+o4/htvd0TCa6kscz5V53/3mLCh9rsb+VpNB7YpNyf8@public.gmane.org>
2018-02-15 8:35 ` Lorenzo Colitti via Containers
2018-02-15 16:05 ` Andy Lutomirski
2018-02-16 18:39 ` Sargun Dhillon
-- strict thread matches above, loose matches on Subject: below --
2018-02-13 15:42 Sargun Dhillon
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