linux-kernel - [patch] fsnotify: potential use after free

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-next>] [day] [month] [year] [list]

Date:	Mon, 22 Jul 2013 09:53:27 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Lino Sanfilippo <LinoSanfilippo@....de>
Cc:	Eric Paris <eparis@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] fsnotify: potential use after free

My static checker complains that if we drop the last reference then it
would be a use after free.  I don't know if it's possible, but really
the atomic_dec(&group->num_marks); should be done while we are holding a
reference to "group".

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 923fe4a..27e357e 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -262,9 +262,9 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
 err:
 	mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
 	list_del_init(&mark->g_list);
+	atomic_dec(&group->num_marks);
 	fsnotify_put_group(group);
 	mark->group = NULL;
-	atomic_dec(&group->num_marks);
 
 	spin_unlock(&mark->lock);
 
--
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/