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

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@vger.kernel.org
Reported-by: Steven Vittitoe <scvitti@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index ecc2cbf300cc..29a74c1efcb8 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);