[PATCH 3.11 059/272] HID: uhid: fix leak for 64/32 UHID_CREATE

[Luis Henriques]

3.11.10.1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Herrmann <dh.herrmann@xxxxxxxxx>

commit 80897aa787ecd58eabb29deab7cbec9249c9b7e6 upstream.

UHID allows short writes so user-space can omit unused fields. We
automatically set them to 0 in the kernel. However, the 64/32 bit
compat-handler didn't do that in the UHID_CREATE fallback. This will
reveal random kernel heap data (of random size, even) to user-space.

Fixes: befde0226a59 ('HID: uhid: make creating devices work on 64/32 systems')

Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 drivers/hid/uhid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 145a4cb..0bb3bb8 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -312,7 +312,7 @@ static int uhid_event_from_user(const char __user *buffer, size_t len,
 			 */
 			struct uhid_create_req_compat *compat;
 
-			compat = kmalloc(sizeof(*compat), GFP_KERNEL);
+			compat = kzalloc(sizeof(*compat), GFP_KERNEL);
 			if (!compat)
 				return -ENOMEM;
 
-- 
1.8.3.2

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