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From: Andi Kleen <ak@suse.de>
To: Christoph Lameter <clameter@sgi.com>
Cc: akpm@osdl.org, linux-mm@kvack.org
Subject: Re: Extract have_task_perm() from kill and migrate functions.
Date: Mon, 22 May 2006 16:36:02 +0200	[thread overview]
Message-ID: <200605221636.02407.ak@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.64.0605220719310.3432@schroedinger.engr.sgi.com>

Why is this on linux-mm? Wouldn't it more for linux-kernel?

> ptrace() has a variation on the have_task_perm() check in may_attach().
> ptrace checks for uid equal to euid, suid, uid or gid equal to
> egid sgid,gid. So one may not be able to kill a process explicyly
> but be able to ptrace() (and then PTRACE_KILL it) if one is a member
> of the same group? Weird.

Sounds like a bug yes. I would suggest to switch it to the stricter
test from kill()


> 
> Plus ptrace does not support eid comparision. So explicit rights
> for ptracing cannot be set via the super user bit.

That might even have a deeper meaning. I remember there were
subtle bugs in this area long ago. But likely it is a bug too.

-Andi

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  reply	other threads:[~2006-05-22 14:36 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-22 14:21 Christoph Lameter
2006-05-22 14:36 ` Andi Kleen [this message]
2006-05-22 15:03 ` James Morris

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