Fake USB devices can send their own report descriptors for which the input_mapping() hook does not get called. In this case, msc->input stays NULL, leading to a crash at a later time.

Detect this condition in the input_configured() hook and reject the device.

This is not supposed to happen with actual magic mouse devices, but can be provoked by imposing as a magic mouse USB device.

Cc: stable@vger.kernel.org Signed-off-by: Günther Noack gnoack@google.com --- drivers/hid/hid-magicmouse.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c index 6e7c189f4d1d..b8932f02b6ee 100644 --- a/drivers/hid/hid-magicmouse.c +++ b/drivers/hid/hid-magicmouse.c @@ -726,6 +726,11 @@ static int magicmouse_input_configured(struct hid_device *hdev, struct magicmouse_sc *msc = hid_get_drvdata(hdev); int ret;

+ if (!msc->input) { + hid_err(hdev, "magicmouse setup input failed (no input)"); + return -EINVAL; + } + ret = magicmouse_setup_input(msc->input, hdev); if (ret) { hid_err(hdev, "magicmouse setup input failed (%d)\n", ret);