From: Kees Cook <keescook@chromium.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Valentin Rothberg <vrothber@redhat.com>,
Jann Horn <jannh@google.com>, YiFei Zhu <yifeifz2@illinois.edu>,
Linux Containers <containers@lists.linux-foundation.org>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
kernel list <linux-kernel@vger.kernel.org>,
Hubertus Franke <frankeh@us.ibm.com>,
Jack Chen <jianyan2@illinois.edu>,
Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
Josep Torrellas <torrella@illinois.edu>,
Will Drewry <wad@chromium.org>, bpf <bpf@vger.kernel.org>,
Tianyin Xu <tyxu@illinois.edu>
Subject: Re: [PATCH v2 seccomp 3/6] seccomp/cache: Add "emulator" to check if filter is arg-dependent
Date: Fri, 25 Sep 2020 21:35:01 -0700 [thread overview]
Message-ID: <202009252134.871EFAB61@keescook> (raw)
In-Reply-To: <05109FF5-65C9-491E-9D9D-2FECE4F8B2B0@amacapital.net>
On Fri, Sep 25, 2020 at 07:47:47PM -0700, Andy Lutomirski wrote:
>
> > On Sep 25, 2020, at 6:23 PM, YiFei Zhu <zhuyifei1999@gmail.com> wrote:
> >
> > On Fri, Sep 25, 2020 at 4:07 PM Andy Lutomirski <luto@amacapital.net> wrote:
> >> We'd need at least three states per syscall: unknown, always-allow,
> >> and need-to-run-filter.
> >>
> >> The downsides are less determinism and a bit of an uglier
> >> implementation. The upside is that we don't need to loop over all
> >> syscalls at load -- instead the time that each operation takes is
> >> independent of the total number of syscalls on the system. And we can
> >> entirely avoid, say, evaluating the x32 case until the task tries an
> >> x32 syscall.
> >
> > I was really afraid of multiple tasks writing to the bitmaps at once,
> > hence I used bitmap-per-task. Now I think about it, if this stays
> > lockless, the worst thing that can happen is that a write undo a bit
> > set by another task. In this case, if the "known" bit is cleared then
> > the worst would be the emulation is run many times. But if the "always
> > allow" is cleared but not "known" bit then we have an issue: the
> > syscall will always be executed in BPF.
> >
>
> If you interleave the bits, then you can read and write them atomically — both bits for any given syscall will be in the same word.
I think we can just hold the spinlock. :)
--
Kees Cook
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next prev parent reply other threads:[~2020-09-26 4:35 UTC|newest]
Thread overview: 151+ 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 via Containers
2020-09-21 18:38 ` Jann Horn via Containers
2020-09-21 23:44 ` YiFei Zhu
2020-09-22 0:25 ` Jann Horn via Containers
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 via Containers
2020-09-21 22:50 ` YiFei Zhu
2020-09-21 22:57 ` Jann Horn via Containers
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 via Containers
2020-09-25 0:18 ` Al Viro
2020-09-25 0:24 ` Jann Horn via Containers
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
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 via Containers
2020-09-21 19:35 ` Hubertus Franke
2020-09-21 19:45 ` Jann Horn via Containers
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 via Containers
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 [this message]
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 via Containers
2020-09-30 22:53 ` Kees Cook
2020-09-30 23:15 ` Jann Horn via Containers
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 via Containers
2020-09-30 22:49 ` Kees Cook
2020-10-01 11:28 ` YiFei Zhu
2020-10-01 21:08 ` Jann Horn via Containers
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 via Containers
2020-09-30 23:12 ` Kees Cook
2020-10-01 12:06 ` YiFei Zhu
2020-10-01 16:05 ` Jann Horn via Containers
2020-10-01 16:18 ` YiFei Zhu
2020-09-30 22:59 ` Kees Cook
2020-09-30 23:08 ` Jann Horn via Containers
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 via Containers
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 via Containers
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 21:24 ` kernel test robot
2020-10-09 21:45 ` Jann Horn via Containers
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 via Containers
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 via Containers
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 via Containers
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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