Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755505Ab1CKV2t (ORCPT ); Fri, 11 Mar 2011 16:28:49 -0500 Received: from smtp.outflux.net ([198.145.64.163]:43891 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754940Ab1CKV2r (ORCPT ); Fri, 11 Mar 2011 16:28:47 -0500 Date: Fri, 11 Mar 2011 13:27:47 -0800 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Alexey Dobriyan , Kees Cook , David Howells , Eugene Teo , Martin Schwidefsky Subject: [PATCH] proc: protect mm start_code/end_code in /proc/pid/stat Message-ID: <20110311212747.GA27618@outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Organization: Canonical X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1412 Lines: 44 While mm->start_stack was protected from cross-uid viewing (commit f83ce3e6b02d5e48b3a43b001390e2b58820389d), 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. CVE-2011-0726 Signed-off-by: Kees Cook Cc: stable@kernel.org --- fs/proc/array.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 7c99c1c..5e4f776 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -489,8 +489,8 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 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, -- 1.7.4.1 -- Kees Cook Ubuntu Security Team -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/