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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index 7cf3ffe..81356f6 100644 (file)
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -308,6 +308,11 @@ 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);
@@ -331,6 +336,11 @@ 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);