linux-kernel - Re: [PATCH] fs: block cross-uid sticky symlinks

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Message-ID: <20100528183920.GJ6056@outflux.net>
Date:	Fri, 28 May 2010 11:39:20 -0700
From:	Kees Cook <kees.cook@...onical.com>
To:	"Serge E. Hallyn" <serue@...ibm.com>
Cc:	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org, linux-doc@...r.kernel.org,
	Randy Dunlap <rdunlap@...otime.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jiri Kosina <jkosina@...e.cz>,
	Dave Young <hidave.darkstar@...il.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	James Morris <jmorris@...ei.org>,
	Eric Paris <eparis@...hat.com>,
	David Howells <dhowells@...hat.com>,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Tim Gardner <tim.gardner@...onical.com>
Subject: Re: [PATCH] fs: block cross-uid sticky symlinks

Hi,

On Thu, May 27, 2010 at 11:40:26PM -0500, Serge E. Hallyn wrote:
> > +	if (S_ISLNK(inode->i_mode) &&
> 
> Q: is the S_ISLNK() check actually needed?

I guess not -- I would imagine this function would never be called if it
wasn't true, and the caller would probably run into bigger problems first
anyway.  I will drop this test.

Thanks,

-Kees

-- 
Kees Cook
Ubuntu Security Team
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