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From: Kees Cook <keescook@chromium.org>
To: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: Jann Horn <jannh@google.com>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Tycho Andersen <tycho@tycho.pizza>,
	Andy Lutomirski <luto@amacapital.net>,
	Will Drewry <wad@chromium.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Giuseppe Scrivano <gscrivan@redhat.com>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
	Valentin Rothberg <vrothber@redhat.com>,
	Hubertus Franke <frankeh@us.ibm.com>, bpf <bpf@vger.kernel.org>,
	Linux Containers <containers@lists.linux-foundation.org>,
	linux-api@vger.kernel.org,
	kernel list <linux-kernel@vger.kernel.org>,
	Jack Chen <jianyan2@illinois.edu>,
	Josep Torrellas <torrella@illinois.edu>,
	Tianyin Xu <tyxu@illinois.edu>, YiFei Zhu <yifeifz2@illinois.edu>
Subject: Re: [PATCH 3/6] seccomp: Implement constant action bitmaps
Date: Thu, 24 Sep 2020 00:38:19 -0700	[thread overview]
Message-ID: <202009240037.21A9E3CE@keescook> (raw)
In-Reply-To: <CABqSeAS=b6NQ=mqrD=hV60md3isYSDyAnE9QE_AT4=oYYFkAfQ@mail.gmail.com>

On Wed, Sep 23, 2020 at 07:36:47PM -0500, YiFei Zhu wrote:
> On Wed, Sep 23, 2020 at 6:29 PM Kees Cook <keescook@chromium.org> wrote:
> > In order to optimize these cases from O(n) to O(1), seccomp can
> > use bitmaps to immediately determine the desired action. A critical
> > observation in the prior paragraph bears repeating: the common case for
> > syscall tests do not check arguments. For any given filter, there is a
> > constant mapping from the combination of architecture and syscall to the
> > seccomp action result. (For kernels/architectures without CONFIG_COMPAT,
> > there is a single architecture.). As such, it is possible to construct
> > a mapping of arch/syscall to action, which can be updated as new filters
> > are attached to a process.
> 
> Would you mind educating me how this patch plan one handling MIPS? For
> one kernel they seem to have up to three arch numbers per build,
> AUDIT_ARCH_MIPS{,64,64N32}. Though ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
> does not seem to be defined for MIPS so I'm assuming the syscall
> numbers are the same, but I think it is possible some client uses that
> arch number to pose different constraints for different processes, so
> it would better not accelerate them rather than break them.

I'll take a look, but I'm hoping it won't be too hard to fit into what
I've got designed so for to deal with x86_x32. (Will MIPS want this
optimization at all?)

-- 
Kees Cook

WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	Giuseppe Scrivano <gscrivan@redhat.com>,
	Will Drewry <wad@chromium.org>, bpf <bpf@vger.kernel.org>,
	Jann Horn <jannh@google.com>, YiFei Zhu <yifeifz2@illinois.edu>,
	linux-api@vger.kernel.org,
	Linux Containers <containers@lists.linux-foundation.org>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Hubertus Franke <frankeh@us.ibm.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Valentin Rothberg <vrothber@redhat.com>,
	Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
	Jack Chen <jianyan2@illinois.edu>,
	Josep Torrellas <torrella@illinois.edu>,
	Tianyin Xu <tyxu@illinois.edu>,
	kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/6] seccomp: Implement constant action bitmaps
Date: Thu, 24 Sep 2020 00:38:19 -0700	[thread overview]
Message-ID: <202009240037.21A9E3CE@keescook> (raw)
In-Reply-To: <CABqSeAS=b6NQ=mqrD=hV60md3isYSDyAnE9QE_AT4=oYYFkAfQ@mail.gmail.com>

On Wed, Sep 23, 2020 at 07:36:47PM -0500, YiFei Zhu wrote:
> On Wed, Sep 23, 2020 at 6:29 PM Kees Cook <keescook@chromium.org> wrote:
> > In order to optimize these cases from O(n) to O(1), seccomp can
> > use bitmaps to immediately determine the desired action. A critical
> > observation in the prior paragraph bears repeating: the common case for
> > syscall tests do not check arguments. For any given filter, there is a
> > constant mapping from the combination of architecture and syscall to the
> > seccomp action result. (For kernels/architectures without CONFIG_COMPAT,
> > there is a single architecture.). As such, it is possible to construct
> > a mapping of arch/syscall to action, which can be updated as new filters
> > are attached to a process.
> 
> Would you mind educating me how this patch plan one handling MIPS? For
> one kernel they seem to have up to three arch numbers per build,
> AUDIT_ARCH_MIPS{,64,64N32}. Though ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
> does not seem to be defined for MIPS so I'm assuming the syscall
> numbers are the same, but I think it is possible some client uses that
> arch number to pose different constraints for different processes, so
> it would better not accelerate them rather than break them.

I'll take a look, but I'm hoping it won't be too hard to fit into what
I've got designed so for to deal with x86_x32. (Will MIPS want this
optimization at all?)

-- 
Kees Cook
_______________________________________________
Containers mailing list
Containers@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/containers

  reply	other threads:[~2020-09-24  7:38 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-23 23:29 [PATCH v1 0/6] seccomp: Implement constant action bitmaps Kees Cook
2020-09-23 23:29 ` Kees Cook
2020-09-23 23:29 ` [PATCH 1/6] seccomp: Introduce SECCOMP_PIN_ARCHITECTURE Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-24  0:41   ` Jann Horn
2020-09-24  0:41     ` Jann Horn via Containers
2020-09-24  7:11     ` Kees Cook
2020-09-24  7:11       ` Kees Cook
2020-09-23 23:29 ` [PATCH 2/6] x86: Enable seccomp architecture tracking Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-24  0:45   ` Jann Horn
2020-09-24  0:45     ` Jann Horn via Containers
2020-09-24  7:12     ` Kees Cook
2020-09-24  7:12       ` Kees Cook
2020-09-23 23:29 ` [PATCH 3/6] seccomp: Implement constant action bitmaps Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-24  0:25   ` Jann Horn
2020-09-24  0:25     ` Jann Horn via Containers
2020-09-24  7:36     ` Kees Cook
2020-09-24  7:36       ` Kees Cook
2020-09-24  8:07       ` YiFei Zhu
2020-09-24  8:07         ` YiFei Zhu
2020-09-24  8:15         ` Kees Cook
2020-09-24  8:15           ` Kees Cook
2020-09-24  8:22           ` YiFei Zhu
2020-09-24  8:22             ` YiFei Zhu
2020-09-24 12:28       ` Jann Horn
2020-09-24 12:28         ` Jann Horn via Containers
2020-09-24 12:37         ` David Laight
2020-09-24 12:37           ` David Laight
2020-09-24 12:56           ` Jann Horn
2020-09-24 12:56             ` Jann Horn via Containers
     [not found]   ` <DM6PR11MB271492D0565E91475D949F5DEF390@DM6PR11MB2714.namprd11.prod.outlook.com>
2020-09-24  0:36     ` YiFei Zhu
2020-09-24  0:36       ` YiFei Zhu
2020-09-24  7:38       ` Kees Cook [this message]
2020-09-24  7:38         ` Kees Cook
2020-09-24  7:51         ` YiFei Zhu
2020-09-24  7:51           ` YiFei Zhu
2020-09-23 23:29 ` [PATCH 4/6] seccomp: Emulate basic filters for constant action results Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-23 23:47   ` Jann Horn
2020-09-23 23:47     ` Jann Horn via Containers
2020-09-24  7:46     ` Kees Cook
2020-09-24  7:46       ` Kees Cook
2020-09-24 15:28       ` Paul Moore
2020-09-24 15:28         ` Paul Moore
2020-09-24 19:52         ` Kees Cook
2020-09-24 19:52           ` Kees Cook
2020-09-24 20:46           ` Paul Moore
2020-09-24 20:46             ` Paul Moore
2020-09-24 21:35             ` Kees Cook
2020-09-24 21:35               ` Kees Cook
2020-09-24 13:16   ` kernel test robot
2020-09-23 23:29 ` [PATCH 5/6] selftests/seccomp: Compare bitmap vs filter overhead Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-23 23:29 ` [PATCH 6/6] [DEBUG] seccomp: Report bitmap coverage ranges Kees Cook
2020-09-23 23:29   ` Kees Cook
2020-09-24 13:40 ` [PATCH v1 0/6] seccomp: Implement constant action bitmaps Rasmus Villemoes
2020-09-24 13:40   ` Rasmus Villemoes
2020-09-24 13:58   ` YiFei Zhu
2020-09-24 13:58     ` YiFei Zhu
2020-09-25  5:56     ` Rasmus Villemoes
2020-09-25  5:56       ` Rasmus Villemoes
2020-09-25  7:07       ` YiFei Zhu
2020-09-25  7:07         ` YiFei Zhu
2020-09-26 18:11         ` YiFei Zhu
2020-09-26 18:11           ` YiFei Zhu
2020-09-28 20:04           ` Kees Cook
2020-09-28 20:04             ` Kees Cook
2020-09-28 20:16             ` YiFei Zhu
2020-09-28 20:16               ` YiFei Zhu
2020-09-24 14:05   ` Jann Horn
2020-09-24 14:05     ` Jann Horn via Containers
2020-09-24 18:57 ` Andrea Arcangeli
2020-09-24 18:57   ` Andrea Arcangeli
2020-09-24 19:18   ` Jann Horn
2020-09-24 19:18     ` Jann Horn via Containers
     [not found]   ` <9dbe8e3bbdad43a1872202ff38c34ca2@DM5PR11MB1692.namprd11.prod.outlook.com>
2020-09-24 19:48     ` Tianyin Xu
2020-09-24 19:48       ` Tianyin Xu
2020-09-24 20:00   ` Kees Cook
2020-09-24 20:00     ` Kees Cook

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