linux-kernel - [PATCH] [229/275] proc: protect mm start_code/end

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20110330210754.CFC573E1A05@tassilo.jf.intel.com>
Date:	Wed, 30 Mar 2011 14:07:54 -0700 (PDT)
From:	Andi Kleen <andi@...stfloor.org>
To:	kees.cook@...onical.com, ak@...ux.intel.com, adobriyan@...il.com,
	dhowells@...hat.com, eugeneteo@...nel.sg, schwidefsky@...ibm.com,
	spender@...ecurity.net, akpm@...ux-foundation.org,
	torvalds@...ux-foundation.org, gregkh@...e.de,
	linux-kernel@...r.kernel.org, stable@...nel.org,
	tim.bird@...sony.com
Subject: [PATCH] [229/275] proc: protect mm start_code/end_code in /proc/pid/stat

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Kees Cook <kees.cook@...onical.com>

commit 5883f57ca0008ffc93e09cbb9847a1928e50c6f3 upstream.

While mm->start_stack was protected from cross-uid viewing (commit
f83ce3e6b02d5 ("proc: avoid information leaks to non-privileged
processes")), the start_code and end_code values were not.  This would
allow the text location of a PIE binary to leak, defeating ASLR.

Note that the value "1" is used instead of "0" for a protected value since
"ps", "killall", and likely other readers of /proc/pid/stat, take
start_code of "0" to mean a kernel thread and will misbehave.  Thanks to
Brad Spengler for pointing this out.

Addresses CVE-2011-0726

Signed-off-by: Kees Cook <kees.cook@...onical.com>
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Cc: Alexey Dobriyan <adobriyan@...il.com>
Cc: David Howells <dhowells@...hat.com>
Cc: Eugene Teo <eugeneteo@...nel.sg>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: Brad Spengler <spender@...ecurity.net>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 fs/proc/array.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6.35.y/fs/proc/array.c
===================================================================
--- linux-2.6.35.y.orig/fs/proc/array.c	2011-03-29 23:03:00.892277339 -0700
+++ linux-2.6.35.y/fs/proc/array.c	2011-03-29 23:03:02.997223479 -0700
@@ -489,8 +489,8 @@
 		vsize,
 		mm ? get_mm_rss(mm) : 0,
 		rsslim,
-		mm ? mm->start_code : 0,
-		mm ? mm->end_code : 0,
+		mm ? (permitted ? mm->start_code : 1) : 0,
+		mm ? (permitted ? mm->end_code : 1) : 0,
 		(permitted && mm) ? mm->start_stack : 0,
 		esp,
 		eip,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/