Code: static int logi_dj_ll_raw_request(struct hid_device *hid,
				  unsigned char reportnum, __u8 *buf,
				  size_t count, unsigned char report_type,
				  int reqtype)
{
	struct dj_device *djdev = hid->driver_data;
	struct dj_receiver_dev *djrcv_dev = djdev->dj_receiver_dev;
	u8 *out_buf;
	int ret;

	if (buf[0] != REPORT_TYPE_LEDS)
		return -EINVAL;

	out_buf = kzalloc(DJREPORT_SHORT_LENGTH, GFP_ATOMIC);
 	if (!out_buf)
 		return -ENOMEM;
 
	if (count < DJREPORT_SHORT_LENGTH - 2)
 		count = DJREPORT_SHORT_LENGTH - 2;
 
 	out_buf[0] = REPORT_ID_DJ_SHORT;
	out_buf[1] = djdev->device_index;
	memcpy(out_buf + 2, buf, count);

	ret = hid_hw_raw_request(djrcv_dev->hdev, out_buf[0], out_buf,
		DJREPORT_SHORT_LENGTH, report_type, reqtype);

	kfree(out_buf);
	return ret;
}

Vulnerability Type: DoS Exec Code Overflow 
CWE ID: CWE-119
Summary: Heap-based buffer overflow in the logi_dj_ll_raw_request function in drivers/hid/hid-logitech-dj.c in the Linux kernel before 3.16.2 allows physically proximate attackers to cause a denial of service (system crash) or possibly execute arbitrary code via a crafted device that specifies a large report size for an LED report.
Commit Message: HID: logitech: fix bounds checking on LED report size

The check on report size for REPORT_TYPE_LEDS in logi_dj_ll_raw_request()
is wrong; the current check doesn't make any sense -- the report allocated
by HID core in hid_hw_raw_request() can be much larger than
DJREPORT_SHORT_LENGTH, and currently logi_dj_ll_raw_request() doesn't
handle this properly at all.

Fix the check by actually trimming down the report size properly if it is
too large.

Cc: stable@vger.kernel.org
Reported-by: Ben Hawkes <hawkes@google.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>