From 412f30105ec6735224535791eed5cdc02888ecb4 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Wed, 28 Aug 2013 22:30:49 +0200
Subject: HID: pantherlord: validate output report details

From: Kees Cook <keescook@chromium.org>

commit 412f30105ec6735224535791eed5cdc02888ecb4 upstream.

A HID device could send a malicious output report that would cause the
pantherlord HID driver to write beyond the output report allocation
during initialization, causing a heap overflow:

[  310.939483] usb 1-1: New USB device found, idVendor=0e8f, idProduct=0003
...
[  315.980774] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten

CVE-2013-2892

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hid/hid-pl.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/hid/hid-pl.c
+++ b/drivers/hid/hid-pl.c
@@ -128,8 +128,14 @@ static int plff_init(struct hid_device *
 			strong = &report->field[0]->value[2];
 			weak = &report->field[0]->value[3];
 			debug("detected single-field device");
-		} else if (report->maxfield >= 4 && report->field[0]->maxusage == 1 &&
-				report->field[0]->usage[0].hid == (HID_UP_LED | 0x43)) {
+		} else if (report->field[0]->maxusage == 1 &&
+			   report->field[0]->usage[0].hid ==
+				(HID_UP_LED | 0x43) &&
+			   report->maxfield >= 4 &&
+			   report->field[0]->report_count >= 1 &&
+			   report->field[1]->report_count >= 1 &&
+			   report->field[2]->report_count >= 1 &&
+			   report->field[3]->report_count >= 1) {
 			report->field[0]->value[0] = 0x00;
 			report->field[1]->value[0] = 0x00;
 			strong = &report->field[2]->value[0];