From: Peter Wu <peter@lekensteyn.nl>
Date: Tue, 16 Dec 2014 15:55:22 +0000 (+0100)
Subject: HID: logitech-hidpp: check WTP report length
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0b3f6569a560aa68c9c50cae0e1bc401f7ee699f;p=linux-beck.git

HID: logitech-hidpp: check WTP report length

Malicious USB devices can send bogus reports smaller than the expected
buffer size. Ensure that the length for WTP reports is valid to avoid
reading out of bounds.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 2f420c0b6609..dd3c21b52de3 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -794,6 +794,11 @@ static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
 
 	switch (data[0]) {
 	case 0x02:
+		if (size < 2) {
+			hid_err(hdev, "Received HID report of bad size (%d)",
+				size);
+			return 1;
+		}
 		if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS) {
 			input_event(wd->input, EV_KEY, BTN_LEFT,
 					!!(data[1] & 0x01));
@@ -806,6 +811,7 @@ static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
 			return wtp_mouse_raw_xy_event(hidpp, &data[7]);
 		}
 	case REPORT_ID_HIDPP_LONG:
+		/* size is already checked in hidpp_raw_event. */
 		if ((report->fap.feature_index != wd->mt_feature_index) ||
 		    (report->fap.funcindex_clientid != EVENT_TOUCHPAD_RAW_XY))
 			return 1;