From: Christian Brauner <christian.brauner@ubuntu.com>
To: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: containers@lists.linux-foundation.org,
YiFei Zhu <yifeifz2@illinois.edu>,
bpf@vger.kernel.org, Andrea Arcangeli <aarcange@redhat.com>,
Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Hubertus Franke <frankeh@us.ibm.com>,
Jack Chen <jianyan2@illinois.edu>,
Josep Torrellas <torrella@illinois.edu>,
Kees Cook <keescook@chromium.org>, Tianyin Xu <tyxu@illinois.edu>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Valentin Rothberg <vrothber@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>, Jann Horn <jannh@google.com>,
Aleksa Sarai <cyphar@cyphar.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH seccomp 0/2] seccomp: Add bitmap cache of arg-independent filter results that allow syscalls
Date: Mon, 21 Sep 2020 10:30:45 +0200 [thread overview]
Message-ID: <20200921083045.ojlswvusrfzohp2d@wittgenstein> (raw)
In-Reply-To: <cover.1600661418.git.yifeifz2@illinois.edu>
On Mon, Sep 21, 2020 at 12:35:16AM -0500, YiFei Zhu wrote:
> From: YiFei Zhu <yifeifz2@illinois.edu>
>
> This series adds a bitmap to cache seccomp filter results if the
> result permits a syscall and is indepenent of syscall arguments.
> This visibly decreases seccomp overhead for most common seccomp
> filters with very little memory footprint.
This is missing some people so expanding the Cc a little. Make sure to
run scripts/get_maintainers.pl next time, in case you forgot. (Adding
Andy, Will, Jann, Aleksa at least.)
Christian
>
> The overhead of running Seccomp filters has been part of some past
> discussions [1][2][3]. Oftentimes, the filters have a large number
> of instructions that check syscall numbers one by one and jump based
> on that. Some users chain BPF filters which further enlarge the
> overhead. A recent work [6] comprehensively measures the Seccomp
> overhead and shows that the overhead is non-negligible and has a
> non-trivial impact on application performance.
>
> We propose SECCOMP_CACHE, a cache-based solution to minimize the
> Seccomp overhead. The basic idea is to cache the result of each
> syscall check to save the subsequent overhead of executing the
> filters. This is feasible, because the check in Seccomp is stateless.
> The checking results of the same syscall ID and argument remains
> the same.
>
> We observed some common filters, such as docker's [4] or
> systemd's [5], will make most decisions based only on the syscall
> numbers, and as past discussions considered, a bitmap where each bit
> represents a syscall makes most sense for these filters.
>
> In the past Kees proposed [2] to have an "add this syscall to the
> reject bitmask". It is indeed much easier to securely make a reject
> accelerator to pre-filter syscalls before passing to the BPF
> filters, considering it could only strengthen the security provided
> by the filter. However, ultimately, filter rejections are an
> exceptional / rare case. Here, instead of accelerating what is
> rejected, we accelerate what is allowed. In order not to compromise
> the security rules the BPF filters defined, any accept-side
> accelerator must complement the BPF filters rather than replacing them.
>
> Statically analyzing BPF bytecode to see if each syscall is going to
> always land in allow or reject is more of a rabbit hole, especially
> there is no current in-kernel infrastructure to enumerate all the
> possible architecture numbers for a given machine. So rather than
> doing that, we propose to cache the results after the BPF filters are
> run. And since there are filters like docker's who will check
> arguments of some syscalls, but not all or none of the syscalls, when
> a filter is loaded we analyze it to find whether each syscall is
> cacheable (does not access syscall argument or instruction pointer) by
> following its control flow graph, and store the result for each filter
> in a bitmap. Changes to architecture number or the filter are expected
> to be rare and simply cause the cache to be cleared. This solution
> shall be fully transparent to userspace.
>
> Ongoing work is to further support arguments with fast hash table
> lookups. We are investigating the performance of doing so [6], and how
> to best integrate with the existing seccomp infrastructure.
>
> We have done some benchmarks with patch applied against bpf-next
> commit 2e80be60c465 ("libbpf: Fix compilation warnings for 64-bit printf args").
>
> Me, in qemu-kvm x86_64 VM, on Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz,
> average results:
>
> Without cache, seccomp_benchmark:
> Current BPF sysctl settings:
> net.core.bpf_jit_enable = 1
> net.core.bpf_jit_harden = 0
> Calibrating sample size for 15 seconds worth of syscalls ...
> Benchmarking 23486415 syscalls...
> 16.079642020 - 1.013345439 = 15066296581 (15.1s)
> getpid native: 641 ns
> 32.080237410 - 16.080763500 = 15999473910 (16.0s)
> getpid RET_ALLOW 1 filter: 681 ns
> 48.609461618 - 32.081296173 = 16528165445 (16.5s)
> getpid RET_ALLOW 2 filters: 703 ns
> Estimated total seccomp overhead for 1 filter: 40 ns
> Estimated total seccomp overhead for 2 filters: 62 ns
> Estimated seccomp per-filter overhead: 22 ns
> Estimated seccomp entry overhead: 18 ns
>
> With cache:
> Current BPF sysctl settings:
> net.core.bpf_jit_enable = 1
> net.core.bpf_jit_harden = 0
> Calibrating sample size for 15 seconds worth of syscalls ...
> Benchmarking 23486415 syscalls...
> 16.059512499 - 1.014108434 = 15045404065 (15.0s)
> getpid native: 640 ns
> 31.651075934 - 16.060637323 = 15590438611 (15.6s)
> getpid RET_ALLOW 1 filter: 663 ns
> 47.367316169 - 31.652302661 = 15715013508 (15.7s)
> getpid RET_ALLOW 2 filters: 669 ns
> Estimated total seccomp overhead for 1 filter: 23 ns
> Estimated total seccomp overhead for 2 filters: 29 ns
> Estimated seccomp per-filter overhead: 6 ns
> Estimated seccomp entry overhead: 17 ns
>
> Depending on the run estimated seccomp overhead for 2 filters can be
> less than seccomp overhead for 1 filter, resulting in underflow to
> estimated seccomp per-filter overhead:
> Estimated total seccomp overhead for 1 filter: 27 ns
> Estimated total seccomp overhead for 2 filters: 21 ns
> Estimated seccomp per-filter overhead: 18446744073709551610 ns
> Estimated seccomp entry overhead: 33 ns
>
> Jack Chen has also run some benchmarks on a bare metal
> Intel(R) Xeon(R) CPU E3-1240 v3 @ 3.40GHz, with side channel
> mitigations off (spec_store_bypass_disable=off spectre_v2=off mds=off
> pti=off l1tf=off), with BPF JIT on and docker default profile,
> and reported:
>
> unixbench syscall mix (https://github.com/kdlucas/byte-unixbench)
> unconfined: 33295685
> docker default: 20661056 60%
> docker default + cache: 25719937 30%
>
> Patch 1 introduces the static analyzer to check for a given filter,
> whether the CFG loads the syscall arguments for each syscall number.
>
> Patch 2 implements the bitmap cache.
>
> [1] https://lore.kernel.org/linux-security-module/c22a6c3cefc2412cad00ae14c1371711@huawei.com/T/
> [2] https://lore.kernel.org/lkml/202005181120.971232B7B@keescook/T/
> [3] https://github.com/seccomp/libseccomp/issues/116
> [4] https://github.com/moby/moby/blob/ae0ef82b90356ac613f329a8ef5ee42ca923417d/profiles/seccomp/default.json
> [5] https://github.com/systemd/systemd/blob/6743a1caf4037f03dc51a1277855018e4ab61957/src/shared/seccomp-util.c#L270
> [6] Draco: Architectural and Operating System Support for System Call Security
> https://tianyin.github.io/pub/draco.pdf, MICRO-53, Oct. 2020
>
> YiFei Zhu (2):
> seccomp/cache: Add "emulator" to check if filter is arg-dependent
> seccomp/cache: Cache filter results that allow syscalls
>
> arch/x86/Kconfig | 27 +++
> include/linux/seccomp.h | 22 +++
> kernel/seccomp.c | 400 +++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 446 insertions(+), 3 deletions(-)
>
> --
> 2.28.0
next prev parent reply other threads:[~2020-09-21 8:30 UTC|newest]
Thread overview: 149+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 5:35 [RFC PATCH seccomp 0/2] seccomp: Add bitmap cache of arg-independent filter results that allow syscalls YiFei Zhu
2020-09-21 5:35 ` [RFC PATCH seccomp 1/2] seccomp/cache: Add "emulator" to check if filter is arg-dependent YiFei Zhu
2020-09-21 17:47 ` Jann Horn
2020-09-21 18:38 ` Jann Horn
2020-09-21 23:44 ` YiFei Zhu
2020-09-22 0:25 ` Jann Horn
2020-09-22 0:47 ` YiFei Zhu
2020-09-21 5:35 ` [RFC PATCH seccomp 2/2] seccomp/cache: Cache filter results that allow syscalls YiFei Zhu
2020-09-21 18:08 ` Jann Horn
2020-09-21 22:50 ` YiFei Zhu
2020-09-21 22:57 ` Jann Horn
2020-09-21 23:08 ` YiFei Zhu
2020-09-25 0:01 ` [PATCH v2 seccomp 2/6] asm/syscall.h: Add syscall_arches[] array Kees Cook
2020-09-25 0:15 ` Jann Horn
2020-09-25 0:18 ` Al Viro
2020-09-25 0:24 ` Jann Horn
2020-09-25 1:27 ` YiFei Zhu
2020-09-25 3:09 ` Kees Cook
2020-09-25 3:28 ` YiFei Zhu
2020-09-25 16:39 ` YiFei Zhu
2020-09-21 5:48 ` [RFC PATCH seccomp 0/2] seccomp: Add bitmap cache of arg-independent filter results that allow syscalls Sargun Dhillon
2020-09-21 7:13 ` YiFei Zhu
2020-09-21 8:30 ` Christian Brauner [this message]
2020-09-21 8:44 ` YiFei Zhu
2020-09-21 13:51 ` Tycho Andersen
2020-09-21 15:27 ` YiFei Zhu
2020-09-21 16:39 ` Tycho Andersen
2020-09-21 22:57 ` YiFei Zhu
2020-09-21 19:16 ` Jann Horn
[not found] ` <OF8837FC1A.5C0D4D64-ON852585EA.006B677F-852585EA.006BA663@notes.na.collabserv.com>
2020-09-21 19:45 ` Jann Horn
2020-09-23 19:26 ` Kees Cook
2020-09-23 22:54 ` YiFei Zhu
2020-09-24 6:52 ` Kees Cook
2020-09-24 12:06 ` [PATCH seccomp 0/6] " YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 1/6] seccomp: Move config option SECCOMP to arch/Kconfig YiFei Zhu
2020-09-24 12:06 ` YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 2/6] asm/syscall.h: Add syscall_arches[] array YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 3/6] seccomp/cache: Add "emulator" to check if filter is arg-dependent YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 4/6] seccomp/cache: Lookup syscall allowlist for fast path YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 5/6] selftests/seccomp: Compare bitmap vs filter overhead YiFei Zhu
2020-09-24 12:06 ` [PATCH seccomp 6/6] seccomp/cache: Report cache data through /proc/pid/seccomp_cache YiFei Zhu
2020-09-24 12:44 ` [PATCH v2 seccomp 0/6] seccomp: Add bitmap cache of arg-independent filter results that allow syscalls YiFei Zhu
2020-09-24 12:44 ` [PATCH v2 seccomp 1/6] seccomp: Move config option SECCOMP to arch/Kconfig YiFei Zhu
2020-09-24 19:11 ` Kees Cook
2020-10-27 9:52 ` Geert Uytterhoeven
2020-10-27 19:08 ` YiFei Zhu
2020-10-28 0:06 ` Kees Cook
2020-10-28 8:18 ` Geert Uytterhoeven
2020-10-28 9:34 ` Jann Horn
2020-09-24 12:44 ` [PATCH v2 seccomp 2/6] asm/syscall.h: Add syscall_arches[] array YiFei Zhu
2020-09-24 13:47 ` David Laight
2020-09-24 14:16 ` YiFei Zhu
2020-09-24 14:20 ` David Laight
2020-09-24 14:37 ` YiFei Zhu
2020-09-24 16:02 ` YiFei Zhu
2020-09-24 12:44 ` [PATCH v2 seccomp 3/6] seccomp/cache: Add "emulator" to check if filter is arg-dependent YiFei Zhu
2020-09-24 23:25 ` Kees Cook
2020-09-25 3:04 ` YiFei Zhu
2020-09-25 16:45 ` YiFei Zhu
2020-09-25 19:42 ` Kees Cook
2020-09-25 19:51 ` Andy Lutomirski
2020-09-25 20:37 ` Kees Cook
2020-09-25 21:07 ` Andy Lutomirski
2020-09-25 23:49 ` Kees Cook
2020-09-26 0:34 ` Andy Lutomirski
2020-09-26 1:23 ` YiFei Zhu
2020-09-26 2:47 ` Andy Lutomirski
2020-09-26 4:35 ` Kees Cook
2020-09-24 12:44 ` [PATCH v2 seccomp 4/6] seccomp/cache: Lookup syscall allowlist for fast path YiFei Zhu
2020-09-24 23:46 ` Kees Cook
2020-09-25 1:55 ` YiFei Zhu
2020-09-24 12:44 ` [PATCH v2 seccomp 5/6] selftests/seccomp: Compare bitmap vs filter overhead YiFei Zhu
2020-09-24 23:47 ` Kees Cook
2020-09-25 1:35 ` YiFei Zhu
2020-09-24 12:44 ` [PATCH v2 seccomp 6/6] seccomp/cache: Report cache data through /proc/pid/seccomp_cache YiFei Zhu
2020-09-24 23:56 ` Kees Cook
2020-09-25 3:11 ` YiFei Zhu
2020-09-25 3:26 ` Kees Cook
2020-09-30 15:19 ` [PATCH v3 seccomp 0/5] seccomp: Add bitmap cache of constant allow filter results YiFei Zhu
2020-09-30 15:19 ` [PATCH v3 seccomp 1/5] x86: Enable seccomp architecture tracking YiFei Zhu
2020-09-30 21:21 ` Kees Cook
2020-09-30 21:33 ` Jann Horn
2020-09-30 22:53 ` Kees Cook
2020-09-30 23:15 ` Jann Horn
2020-09-30 15:19 ` [PATCH v3 seccomp 2/5] seccomp/cache: Add "emulator" to check if filter is constant allow YiFei Zhu
2020-09-30 22:24 ` Jann Horn
2020-09-30 22:49 ` Kees Cook
2020-10-01 11:28 ` YiFei Zhu
2020-10-01 21:08 ` Jann Horn
2020-09-30 22:40 ` Kees Cook
2020-10-01 11:52 ` YiFei Zhu
2020-10-01 21:05 ` Kees Cook
2020-10-02 11:08 ` YiFei Zhu
2020-10-09 4:47 ` YiFei Zhu
2020-10-09 5:41 ` Kees Cook
2020-09-30 15:19 ` [PATCH v3 seccomp 3/5] seccomp/cache: Lookup syscall allowlist for fast path YiFei Zhu
2020-09-30 21:32 ` Kees Cook
2020-10-09 0:17 ` YiFei Zhu
2020-10-09 5:35 ` Kees Cook
2020-09-30 15:19 ` [PATCH v3 seccomp 4/5] selftests/seccomp: Compare bitmap vs filter overhead YiFei Zhu
2020-09-30 15:19 ` [PATCH v3 seccomp 5/5] seccomp/cache: Report cache data through /proc/pid/seccomp_cache YiFei Zhu
2020-09-30 22:00 ` Jann Horn
2020-09-30 23:12 ` Kees Cook
2020-10-01 12:06 ` YiFei Zhu
2020-10-01 16:05 ` Jann Horn
2020-10-01 16:18 ` YiFei Zhu
2020-09-30 22:59 ` Kees Cook
2020-09-30 23:08 ` Jann Horn
2020-09-30 23:21 ` Kees Cook
2020-10-09 17:14 ` [PATCH v4 seccomp 0/5] seccomp: Add bitmap cache of constant allow filter results YiFei Zhu
2020-10-09 17:14 ` [PATCH v4 seccomp 1/5] seccomp/cache: Lookup syscall allowlist bitmap for fast path YiFei Zhu
2020-10-09 21:30 ` Jann Horn
2020-10-09 23:18 ` Kees Cook
2020-10-09 17:14 ` [PATCH v4 seccomp 2/5] seccomp/cache: Add "emulator" to check if filter is constant allow YiFei Zhu
2020-10-09 21:30 ` Jann Horn
2020-10-09 22:47 ` Kees Cook
2020-10-09 17:14 ` [PATCH v4 seccomp 3/5] x86: Enable seccomp architecture tracking YiFei Zhu
2020-10-09 17:25 ` Andy Lutomirski
2020-10-09 18:32 ` YiFei Zhu
2020-10-09 20:59 ` Andy Lutomirski
2020-10-09 17:14 ` [PATCH v4 seccomp 4/5] selftests/seccomp: Compare bitmap vs filter overhead YiFei Zhu
2020-10-09 17:14 ` [PATCH v4 seccomp 5/5] seccomp/cache: Report cache data through /proc/pid/seccomp_cache YiFei Zhu
2020-10-09 21:45 ` Jann Horn
2020-10-09 23:14 ` Kees Cook
2020-10-10 13:26 ` YiFei Zhu
2020-10-12 22:57 ` Kees Cook
2020-10-13 0:31 ` YiFei Zhu
2020-10-22 20:52 ` YiFei Zhu
2020-10-22 22:32 ` Kees Cook
2020-10-22 23:40 ` YiFei Zhu
2020-10-24 2:51 ` Kees Cook
2020-10-30 12:18 ` YiFei Zhu
2020-11-03 13:00 ` YiFei Zhu
2020-11-04 0:29 ` Kees Cook
2020-11-04 11:40 ` YiFei Zhu
2020-11-04 18:57 ` Kees Cook
2020-10-11 15:47 ` [PATCH v5 seccomp 0/5]seccomp: Add bitmap cache of constant allow filter results YiFei Zhu
2020-10-11 15:47 ` [PATCH v5 seccomp 1/5] seccomp/cache: Lookup syscall allowlist bitmap for fast path YiFei Zhu
2020-10-12 6:42 ` Jann Horn
2020-10-11 15:47 ` [PATCH v5 seccomp 2/5] seccomp/cache: Add "emulator" to check if filter is constant allow YiFei Zhu
2020-10-12 6:46 ` Jann Horn
2020-10-11 15:47 ` [PATCH v5 seccomp 3/5] x86: Enable seccomp architecture tracking YiFei Zhu
2020-10-11 15:47 ` [PATCH v5 seccomp 4/5] selftests/seccomp: Compare bitmap vs filter overhead YiFei Zhu
2020-10-11 15:47 ` [PATCH v5 seccomp 5/5] seccomp/cache: Report cache data through /proc/pid/seccomp_cache YiFei Zhu
2020-10-12 6:49 ` Jann Horn
2020-12-17 12:14 ` Geert Uytterhoeven
2020-12-17 18:34 ` YiFei Zhu
2020-12-18 12:35 ` Geert Uytterhoeven
2020-10-27 19:14 ` [PATCH v5 seccomp 0/5]seccomp: Add bitmap cache of constant allow filter results Kees Cook
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=20200921083045.ojlswvusrfzohp2d@wittgenstein \
--to=christian.brauner@ubuntu.com \
--cc=aarcange@redhat.com \
--cc=bpf@vger.kernel.org \
--cc=containers@lists.linux-foundation.org \
--cc=cyphar@cyphar.com \
--cc=dskarlat@cs.cmu.edu \
--cc=frankeh@us.ibm.com \
--cc=gscrivan@redhat.com \
--cc=jannh@google.com \
--cc=jianyan2@illinois.edu \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=tobin@ibm.com \
--cc=torrella@illinois.edu \
--cc=tyxu@illinois.edu \
--cc=vrothber@redhat.com \
--cc=wad@chromium.org \
--cc=yifeifz2@illinois.edu \
--cc=zhuyifei1999@gmail.com \
/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).