From: TongZhang <ztong@vt.edu>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: adobriyan@gmail.com, akpm@linux-foundation.org,
viro@zeniv.linux.org.uk, LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org,
Wenbo Shen <shenwenbosmile@gmail.com>
Subject: Re: Leaking path for set_task_comm
Date: Tue, 25 Sep 2018 20:44:39 -0400 [thread overview]
Message-ID: <0CD63E6E-7512-4DD6-8858-4408416DC730@vt.edu> (raw)
In-Reply-To: <20180925183953.GI15710@uranus>
Yes, this is exactly what I am saying.
A process can change its own name using prctl or /proc/self/comm.
prctl is protected by security_task_prctl, whereas /proc/self/comm is not protected by this LSM hook.
A system admin may expect to use security_task_prctl to block all attempt to change process name, however, it can still change name using /proc/self/comm.
> On Sep 25, 2018, at 2:39 PM, Cyrill Gorcunov <gorcunov@gmail.com> wrote:
>
> On Tue, Sep 25, 2018 at 01:27:08PM -0400, Tong Zhang wrote:
>> Kernel Version: 4.18.5
>>
>> Problem Description:
>>
>> When using prctl(PR_SET_NAME) to set the thread name, it is checked by security_task_prctl.
>>
>> We discovered a leaking path that can also use method implemented in
>> fs/proc/base.c:1526 comm_write(), to do similar thing without asking LSM’s decision.
>
> I don't understand how it is a problem. Could you please explain?
> procfs/comm is created with S_IRUGO|S_IWUSR permissions. So
> prctl and procfs are simply different interfaces.
next prev parent reply other threads:[~2018-09-26 6:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 17:27 Leaking path for set_task_comm Tong Zhang
2018-09-25 18:39 ` Cyrill Gorcunov
2018-09-26 0:44 ` TongZhang [this message]
2018-09-26 3:16 ` Theodore Y. Ts'o
2018-09-26 22:39 ` Alan Cox
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