From: Antonio Ospite <ospite@studenti.unina.it>
Date: Tue, 5 Oct 2010 15:20:17 +0000 (+0200)
Subject: HID: hidraw, fix a NULL pointer dereference in hidraw_write
X-Git-Tag: v2.6.35.8~92
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cdcaefbcdc06c945dec978a9015f25f86e622844;p=thirdparty%2Fkernel%2Fstable.git

HID: hidraw, fix a NULL pointer dereference in hidraw_write

commit e42dee9a99a3ecd32b5c027e8f7411fb5bc11eb6 upstream.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa0f0a625>] hidraw_write+0x3b/0x116 [hid]
[...]

This is reproducible by disconnecting the device while userspace writes
to dev node in a loop and doesn't check return values in order to exit
the loop.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index f43e95e11d480..7dca2faacdfa2 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -111,6 +111,12 @@ static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t
 	int ret = 0;
 
 	mutex_lock(&minors_lock);
+
+	if (!hidraw_table[minor]) {
+		ret = -ENODEV;
+		goto out;
+	}
+
 	dev = hidraw_table[minor]->hid;
 
 	if (!dev->hid_output_raw_report) {