From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758066AbcHWOVI (ORCPT ); Tue, 23 Aug 2016 10:21:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58862 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757331AbcHWOVD (ORCPT ); Tue, 23 Aug 2016 10:21:03 -0400 From: Mateusz Guzik To: Konstantin Khlebnikov , Richard Guy Briggs Cc: ebiederm@xmission.com, oleg@redhat.com, sgrubb@redhat.com, pmoore@redhat.com, eparis@redhat.com, luto@amacapital.net, linux-audit@redhat.com, linux-kernel@vger.kernel.org, Al Viro Subject: [PATCHv2 2/2] audit: fix exe_file access in audit_exe_compare Date: Tue, 23 Aug 2016 16:20:39 +0200 Message-Id: <1471962039-14940-3-git-send-email-mguzik@redhat.com> In-Reply-To: <1471962039-14940-1-git-send-email-mguzik@redhat.com> References: <1471962039-14940-1-git-send-email-mguzik@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 23 Aug 2016 14:20:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Prior to the change the function would blindly deference mm, exe_file and exe_file->f_inode, each of which could have been NULL or freed. Use get_task_exe_file to safely obtain stable exe_file. Signed-off-by: Mateusz Guzik Acked-by: Konstantin Khlebnikov --- kernel/audit_watch.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index d6709eb..0d302a8 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -19,6 +19,7 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include #include #include #include @@ -544,10 +545,11 @@ int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark) unsigned long ino; dev_t dev; - rcu_read_lock(); - exe_file = rcu_dereference(tsk->mm->exe_file); + exe_file = get_task_exe_file(tsk); + if (!exe_file) + return 0; ino = exe_file->f_inode->i_ino; dev = exe_file->f_inode->i_sb->s_dev; - rcu_read_unlock(); + fput(exe_file); return audit_mark_compare(mark, ino, dev); } -- 1.8.3.1