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From: Ben Hutchings <bhutchings@solarflare.com>
To: Indan Zupancic <indan@nul.nu>
Cc: Will Drewry <wad@chromium.org>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com,
	netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de,
	davem@davemloft.net, hpa@zytor.com, mingo@redhat.com,
	oleg@redhat.com, peterz@infradead.org, rdunlap@xenotime.net,
	mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu,
	eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
	scarybeasts@gmail.com, pmoore@redhat.com,
	akpm@linux-foundation.org, corbet@lwn.net,
	eric.dumazet@gmail.com, markus@chromium.org,
	keescook@chromium.org
Subject: Re: [PATCH v10 05/11] seccomp: add system call filtering using BPF
Date: Wed, 22 Feb 2012 14:23:46 +0000	[thread overview]
Message-ID: <1329920626.3258.174.camel@deadeye> (raw)
In-Reply-To: <38d58caa17befe422065efe5dc451a34.squirrel@webmail.greenhost.nl>

On Wed, 2012-02-22 at 09:19 +0100, Indan Zupancic wrote:
[...]
> Alternative approach: Tell the arch at filter install time and only run the
> filters with the same arch as the current system call. If no filters are run,
> deny the systemcall.
>
> Advantages:
> 
> - Filters don't have to check the arch every syscall entry.
> 
> - Secure by default. Filters don't have to do anything arch specific to
>   be secure, no surprises possible.
> 
> - If a new arch comes into existence, there is no chance of old filters
>   becoming buggy and insecure. This is especially true for archs that
>   had only one mode, but added another one later on: Old filters had no
>   need to check the mode at all.
[...]

What about when there are multiple layers of restrictions?  So long as
any one layer covers the new architecture, there is no default-deny even
though the other layers might not cover it.

I would have thought the way to make sure the architecture is always
checked is to pack it together with the syscall number.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

  parent reply	other threads:[~2012-02-22 14:23 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-21 17:30 [PATCH v10 01/11] sk_run_filter: add support for custom load_pointer Will Drewry
2012-02-21 17:30 ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 02/11] seccomp: kill the seccomp_t typedef Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 03/11] asm/syscall.h: add syscall_get_arch Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 18:46   ` Roland McGrath
2012-02-21 18:46     ` Roland McGrath
2012-02-21 18:57     ` Will Drewry
2012-02-21 18:57       ` Will Drewry
2012-02-21 19:01     ` [PATCH v11 " Will Drewry
2012-02-21 19:01       ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 04/11] arch/x86: add syscall_get_arch to syscall.h Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 05/11] seccomp: add system call filtering using BPF Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-22  6:32   ` H. Peter Anvin
2012-02-22  6:32     ` H. Peter Anvin
2012-02-22 19:48     ` Will Drewry
2012-02-22 19:48       ` Will Drewry
2012-02-22  8:19   ` Indan Zupancic
2012-02-22  8:19     ` Indan Zupancic
2012-02-22 14:23     ` Ben Hutchings [this message]
2012-02-22 19:47       ` Will Drewry
2012-02-22 19:47         ` Will Drewry
2012-02-22 23:46         ` Indan Zupancic
2012-02-22 23:46           ` Indan Zupancic
2012-02-22 23:51           ` Andrew Lutomirski
2012-02-22 23:51             ` Andrew Lutomirski
2012-02-23  0:08             ` Indan Zupancic
2012-02-23  1:07             ` H. Peter Anvin
2012-02-23  1:07               ` H. Peter Anvin
2012-02-22 23:03       ` Indan Zupancic
2012-02-22 19:47     ` Will Drewry
2012-02-22 19:47       ` Will Drewry
2012-02-22 19:53       ` H. Peter Anvin
2012-02-22 19:53         ` H. Peter Anvin
2012-02-22 20:01         ` Will Drewry
2012-02-22 20:01           ` Will Drewry
2012-02-23  0:25       ` Indan Zupancic
2012-02-21 17:30 ` [PATCH v10 06/11] seccomp: add SECCOMP_RET_ERRNO Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 22:41   ` Kees Cook
2012-02-21 22:41     ` Kees Cook
2012-02-21 22:48     ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 07/11] signal, x86: add SIGSYS info and make it synchronous Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-22  8:34   ` Indan Zupancic
2012-02-22  8:34     ` Indan Zupancic
2012-02-22 19:48     ` Will Drewry
2012-02-22 19:48       ` Will Drewry
2012-02-22 23:38       ` Andrew Lutomirski
2012-02-22 23:38         ` Andrew Lutomirski
2012-02-22 23:53         ` Kees Cook
2012-02-22 23:53           ` Kees Cook
2012-02-23  0:05           ` Will Drewry
2012-02-23  0:05             ` Will Drewry
2012-02-23  0:08             ` Kees Cook
2012-02-23  0:08               ` Kees Cook
2012-02-23  0:29               ` H. Peter Anvin
2012-02-23  0:29                 ` H. Peter Anvin
2012-02-23  0:50                 ` Roland McGrath
2012-02-23  1:06                   ` H. Peter Anvin
2012-02-23  1:06                     ` H. Peter Anvin
2012-02-23 17:38                     ` Roland McGrath
2012-02-23 17:38                       ` Roland McGrath
2012-02-23 19:26                       ` Will Drewry
2012-02-23 19:26                         ` Will Drewry
2012-02-23 22:15                         ` Indan Zupancic
2012-02-23 22:15                           ` Indan Zupancic
2012-02-23 22:33                           ` Markus Gutschke
2012-02-23 22:33                             ` Markus Gutschke
2012-02-23 22:36                             ` Will Drewry
2012-02-23 22:36                               ` Will Drewry
2012-02-27 12:32                             ` Indan Zupancic
2012-02-27 12:32                               ` Indan Zupancic
2012-02-27 16:21                               ` Will Drewry
2012-02-27 16:21                                 ` Will Drewry
2012-02-23 22:34                           ` [kernel-hardening] " Will Drewry
2012-02-23 16:44                 ` Will Drewry
2012-02-23 16:44                   ` Will Drewry
2012-02-23  0:11         ` Roland McGrath
2012-02-23  0:11           ` Roland McGrath
2012-02-21 17:30 ` [PATCH v10 08/11] seccomp: Add SECCOMP_RET_TRAP Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 09/11] ptrace,seccomp: Add PTRACE_SECCOMP support Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-22 12:22   ` Indan Zupancic
2012-02-22 12:22     ` Indan Zupancic
2012-02-22 19:47     ` Will Drewry
2012-02-22 19:47       ` [kernel-hardening] " Will Drewry
2012-02-21 17:30 ` [PATCH v10 10/11] x86: Enable HAVE_ARCH_SECCOMP_FILTER Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 17:30 ` [PATCH v10 11/11] Documentation: prctl/seccomp_filter Will Drewry
2012-02-21 17:30   ` Will Drewry
2012-02-21 23:12   ` Kees Cook
2012-02-21 23:12     ` Kees Cook
2012-02-22  3:41     ` Will Drewry

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