[PATCH 1/2] HID: magicmouse: sanity check report size in raw_event() callback

[Jiri Kosina]

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.

Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Steven Vittitoe <scvitti@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
---
 drivers/hid/hid-magicmouse.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index ecc2cbf..29a74c1 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);
-- 
1.9.2
--
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