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From: Chris Wright <chrisw@osdl.org>
To: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@osdl.org>,
	Michael Kerrisk <michael.kerrisk@gmx.net>,
	Linus Torvalds <torvalds@osdl.org>,
	Manfred Spraul <manfred@colorfullife.com>,
	Rik van Riel <riel@redhat.com>, Chris Wright <chrisw@osdl.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] shmtcl SHM_LOCK perms
Date: Tue, 30 Nov 2004 12:50:45 -0800	[thread overview]
Message-ID: <20041130125045.E2357@build.pdx.osdl.net> (raw)
In-Reply-To: <Pine.LNX.4.44.0411291855560.23341-100000@localhost.localdomain>; from hugh@veritas.com on Mon, Nov 29, 2004 at 07:09:18PM +0000

* Hugh Dickins (hugh@veritas.com) wrote:
> Michael Kerrisk has observed that at present any process can SHM_LOCK
> any shm segment of size within process RLIMIT_MEMLOCK, despite having no
> permissions on the segment: surprising, though not obviously evil.  And
> any process can SHM_UNLOCK any shm segment, despite no permissions on it:
> that is surely wrong.

You may be neither the owner, nor the creator of a segment but have read
access to it.  In which case you could simply copy the contents of the
segment anywhere you like, which has similar effect to SHM_UNLOCK from
the point of view of paging out sensitive data.

thanks,
-chris
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net

  reply	other threads:[~2004-11-30 20:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-29 19:09 [PATCH] shmtcl SHM_LOCK perms Hugh Dickins
2004-11-30 20:50 ` Chris Wright [this message]
2004-12-01  1:00   ` Hugh Dickins
2004-12-01  4:55     ` Chris Wright

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