From: Jiri Kosina <jkosina@suse.cz>
Date: Wed, 27 Aug 2014 07:12:24 +0000 (+0200)
Subject: HID: magicmouse: sanity check report size in raw_event() callback
X-Git-Tag: firefly_0821_release~3679^2~1520
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=11677bd1cc851c9dda154095f62d93b2c34afc9c;p=firefly-linux-kernel-4.4.55.git

HID: magicmouse: sanity check report size in raw_event() callback

commit c54def7bd64d7c0b6993336abcffb8444795bf38 upstream.

The report passed to us from transport driver could potentially be
arbitrarily large, therefore we better sanity-check it so that
magicmouse_emit_touch() gets only valid values of raw_id.

Reported-by: Steven Vittitoe <scvitti@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index 5bc37343eb22..c24f3dfd9367 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -290,6 +290,11 @@ static int magicmouse_raw_event(struct hid_device *hdev,
 		if (size < 4 || ((size - 4) % 9) != 0)
 			return 0;
 		npoints = (size - 4) / 9;
+		if (npoints > 15) {
+			hid_warn(hdev, "invalid size value (%d) for TRACKPAD_REPORT_ID\n",
+					size);
+			return 0;
+		}
 		msc->ntouches = 0;
 		for (ii = 0; ii < npoints; ii++)
 			magicmouse_emit_touch(msc, ii, data + ii * 9 + 4);
@@ -307,6 +312,11 @@ static int magicmouse_raw_event(struct hid_device *hdev,
 		if (size < 6 || ((size - 6) % 8) != 0)
 			return 0;
 		npoints = (size - 6) / 8;
+		if (npoints > 15) {
+			hid_warn(hdev, "invalid size value (%d) for MOUSE_REPORT_ID\n",
+					size);
+			return 0;
+		}
 		msc->ntouches = 0;
 		for (ii = 0; ii < npoints; ii++)
 			magicmouse_emit_touch(msc, ii, data + ii * 8 + 6);