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From: Tycho Andersen <tycho@tycho.pizza>
To: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: containers@lists.linux-foundation.org,
	Andrea Arcangeli <aarcange@redhat.com>,
	Giuseppe Scrivano <gscrivan@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	YiFei Zhu <yifeifz2@illinois.edu>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
	Valentin Rothberg <vrothber@redhat.com>,
	Hubertus Franke <frankeh@us.ibm.com>,
	Jack Chen <jianyan2@illinois.edu>,
	Josep Torrellas <torrella@illinois.edu>,
	bpf@vger.kernel.org, Tianyin Xu <tyxu@illinois.edu>
Subject: Re: [RFC PATCH seccomp 0/2] seccomp: Add bitmap cache of arg-independent filter results that allow syscalls
Date: Mon, 21 Sep 2020 07:51:15 -0600	[thread overview]
Message-ID: <20200921135115.GC3794348@cisco> (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.
> 
> 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.

One problem with a kernel config setting is that it's for all tasks.
While docker and systemd may make decsisions based on syscall number,
other applications may have more nuanced filters, and this cache would
yield incorrect results.

You could work around this by making this a filter flag instead;
filter authors would generally know whether their filter results can
be cached and probably be motivated to opt in if their users are
complaining about slow syscall execution.

Tycho

  parent reply	other threads:[~2020-09-21 14:01 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
2020-09-21  8:44   ` YiFei Zhu
2020-09-21 13:51 ` Tycho Andersen [this message]
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

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