linux-kernel - Re: [PATCH 1/1] file capabilities: remove cap_task

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Message-ID: <20080229174007.0a934cc6@mandriva.com.br>
Date:	Fri, 29 Feb 2008 17:40:07 -0300
From:	"Luiz Fernando N. Capitulino" <lcapitulino@...driva.com.br>
To:	serge@...lyn.com
Cc:	lkml <linux-kernel@...r.kernel.org>,
	linux-security-module@...r.kernel.org,
	Andrew Morgan <morgan@...nel.org>,
	Stephen Smalley <sds@...ch.ncsc.mil>,
	Mike Galbraith <efault@....de>, buraphalinuxserver@...il.com,
	elendil@...net.nl
Subject: Re: [PATCH 1/1] file capabilities: remove cap_task_kill()

Em Thu, 28 Feb 2008 11:38:17 -0600
serge@...lyn.com escreveu:

| The original justification for cap_task_kill() was as follows:
| 
| 	check_kill_permission() does appropriate uid equivalence checks.
| 	However with file capabilities it becomes possible for an
| 	unprivileged user to execute a file with file capabilities
| 	resulting in a more privileged task with the same uid.
| 
| However now that cap_task_kill() always returns 0 (permission
| granted) when p->uid==current->uid, the whole hook is worthless,
| and only likely to create more subtle problems in the corner cases
| where it might still be called but return -EPERM.  Those cases
| are basically when uids are different but euid/suid is equivalent
| as per the check in check_kill_permission().
| 
| This patch removes cap_task_kill().

 2.6.24 seems to have the same bug, what about a rediff for it and
submit the patch to -stable team?

 Thanks.

-- 
Luiz Fernando N. Capitulino
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