linux-kernel - [PATCH 2/3] vt: fix locking around vt_bind/vt

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]

Date:	Fri, 12 Dec 2014 18:38:04 +0200
From:	Imre Deak <imre.deak@...el.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] vt: fix locking around vt_bind/vt_unbind

Currently vt_bind and vt_unbind access at least the con_driver object
and registered_con_driver array without holding the console lock. Fix
this by locking around the whole function in each case.

Signed-off-by: Imre Deak <imre.deak@...el.com>
---
 drivers/tty/vt/vt.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 1862e89..5dd1880 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3312,11 +3312,8 @@ static int vt_bind(struct con_driver *con)
 		if (first == 0 && last == MAX_NR_CONSOLES -1)
 			deflt = 1;
 
-		if (first != -1) {
-			console_lock();
+		if (first != -1)
 			do_bind_con_driver(csw, first, last, deflt);
-			console_unlock();
-		}
 
 		first = -1;
 		last = -1;
@@ -3356,9 +3353,7 @@ static int vt_unbind(struct con_driver *con)
 			deflt = 1;
 
 		if (first != -1) {
-			console_lock();
 			ret = do_unbind_con_driver(csw, first, last, deflt);
-			console_unlock();
 			if (ret != 0)
 				return ret;
 		}
@@ -3388,11 +3383,15 @@ static ssize_t store_bind(struct device *dev, struct device_attribute *attr,
 	struct con_driver *con = dev_get_drvdata(dev);
 	int bind = simple_strtoul(buf, NULL, 0);
 
+	console_lock();
+
 	if (bind)
 		vt_bind(con);
 	else
 		vt_unbind(con);
 
+	console_unlock();
+
 	return count;
 }
 
-- 
1.8.4

--
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/