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Date: Tue, 29 Jun 2010 11:45:14 +0300
Message-ID: <AANLkTinlrnSEwnWn_qcvdfqXM6b_bA3hbBjBrqgpQnKX@mail.gmail.com>
Subject: Re: [PATCH] sanitize task->comm to avoid leaking escape codes
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Kees Cook <kees.cook@canonical.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, 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>
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On Tue, Jun 29, 2010 at 12:03 AM, Kees Cook <kees.cook@canonical.com> wrote:
> 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.

It also fills not just any buffer but buffer which is TASK_COMM_LEN byte wide.

> Why should get_task_comm not take a destination buffer length argument?

If you pass too small, you needlessly truncate output.
If you pass too large, you waste space.
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