From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kees Cook <kees.cook@canonical.com>
Subject: Re: [PATCH] sanitize task->comm to avoid leaking escape codes
Date: Mon, 28 Jun 2010 14:03:42 -0700
Message-ID: <20100628210342.GW4175@outflux.net>
References: <20100623181129.GM5876@outflux.net>
 <20100623194145.GA19628@redhat.com>
 <20100623202335.GA4424@x200>
 <20100628130028.73757a46.akpm@linux-foundation.org>
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Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Neil Horman <nhorman@tuxdriver.com>,
	Roland McGrath <roland@redhat.com>,
	Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
To: Andrew Morton <akpm@linux-foundation.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
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In-Reply-To: <20100628130028.73757a46.akpm@linux-foundation.org>
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List-Id: linux-fsdevel.vger.kernel.org

Hi,

On Mon, Jun 28, 2010 at 01:00:28PM -0700, Andrew Morton wrote:
> Surely it would be better to fix the tools which display this info
> rather than making the kernel tell fibs.

The strncpy in get_task_comm() is totally wrong -- it's testing the length
of task->comm.  Why should get_task_comm not take a destination buffer
length argument?  At least consider v2 of the patch -- it just fixes the
get_task_comm definition and callers.

But, if not, then patches to the kernel that include
printk(..., get_task_comm(...) ...) shouldn't be considered flawed[1].

-Kees

[1] http://lkml.org/lkml/2010/6/23/132

-- 
Kees Cook
Ubuntu Security Team