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From: Colin Walters <walters@verbum.org>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Will Drewry <wad@chromium.org>,
	linux-kernel@vger.kernel.org, kees.cook@canonical.com,
	torvalds@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu,
	rostedt@goodmis.org, jmorris@namei.org,
	paulmck@linux.vnet.ibm.com, Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH v4 03/13] seccomp_filters: new mode with configurable syscall filters
Date: Mon, 6 Jun 2011 11:25:17 -0400	[thread overview]
Message-ID: <BANLkTi=WGCrT3Z5qar0P-EqN=aKn9z-HYA@mail.gmail.com> (raw)
In-Reply-To: <1307364487.2876.18.camel@moss-pluto>

On Mon, Jun 6, 2011 at 8:48 AM, Stephen Smalley <sds@tycho.nsa.gov> wrote:
>
> Suppose we did add a MAC check on enabling seccomp.  Under what
> circumstances would we want to deny a process the ability to further
> restrict its own actions?

Well, I could understand a simple argument about limiting the exposed
kernel API; again I know this is sort of ironic, but seccomp is a
pretty complex new API, and there will be processes that *aren't*
using it for whatever reason and might be exploited.

I'm not arguing strongly for this, I just wanted to bring it up.  The
set of hooks seems rather inconsistent right now.

Given the above rationale, why for example is there a SELinux access
vector for sched_getscheduler (process:getsched)?

> Denying the ability to enable seccomp could itself lead to
> vulnerabilities, as applications have shown that they often fail to
> check or handle errors from privilege-limiting calls correctly.

Right.

> The situation would differ if seccomp could be enabled for a different
> target process than current, or if it could be inherited across exec.

It's based on prctl() so only affects the current process, and as for
the latter - it looks like the current state is that if seccomp is
active, exec is always disallowed.

  reply	other threads:[~2011-06-06 15:25 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-03 20:34 [PATCH v4 01/13] tracing: split out filter initialization and clean up Will Drewry
2011-06-03 20:34 ` [PATCH v4 02/13] tracing: split out syscall_trace_enter construction Will Drewry
2011-06-03 20:34 ` [PATCH v4 03/13] seccomp_filters: new mode with configurable syscall filters Will Drewry
2011-06-03 21:48   ` [PATCH v5 " Will Drewry
2011-06-06 16:56     ` [PATCH v6 03/14] " Will Drewry
2011-06-10 15:39       ` [PATCH v7 03/13] " Will Drewry
2011-06-13  2:24         ` [PATCH v8 " Will Drewry
2011-06-03 22:16   ` [PATCH v4 " Colin Walters
2011-06-06 12:48     ` Stephen Smalley
2011-06-06 15:25       ` Colin Walters [this message]
2011-06-06 16:36         ` Stephen Smalley
2011-06-03 20:34 ` [PATCH v4 04/13] seccomp_filter: add process state reporting Will Drewry
2011-06-03 21:50   ` [PATCH v5 " Will Drewry
2011-06-10 15:40     ` [PATCH v7 " Will Drewry
2011-06-07 23:56   ` [PATCH v4 " Paul E. McKenney
2011-06-08  1:05     ` Will Drewry
2011-06-08  1:59       ` Steven Rostedt
2011-06-03 20:34 ` [PATCH v4 05/13] seccomp_filter: Document what seccomp_filter is and how it works Will Drewry
2011-06-03 20:38   ` Kees Cook
2011-06-10 15:40   ` [PATCH v7 " Will Drewry
2011-06-03 20:34 ` [PATCH v4 06/13] x86: add HAVE_SECCOMP_FILTER and seccomp_execve Will Drewry
2011-06-03 20:34 ` [PATCH v4 07/13] arm: select HAVE_SECCOMP_FILTER Will Drewry
2011-06-03 20:34 ` [PATCH v4 08/13] microblaze: select HAVE_SECCOMP_FILTER and provide seccomp_execve Will Drewry
2011-06-03 20:34 ` [PATCH v4 09/13] mips: " Will Drewry
2011-06-03 20:34 ` [PATCH v4 10/13] s390: " Will Drewry
2011-06-03 20:34 ` [PATCH v4 11/13] powerpc: " Will Drewry
2011-06-03 20:34 ` [PATCH v4 12/13] sparc: " Will Drewry
2011-06-03 23:20   ` David Miller
2011-06-03 20:34 ` [PATCH v4 13/13] sh: select HAVE_SECCOMP_FILTER Will Drewry

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