From fc8a47ed624bd29b0ae91fbd96019274c87870cc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= Date: Wed, 5 Jan 2022 18:29:14 +0100 Subject: [PATCH] HID: hid-uclogic-params: Invalid parameter check in uclogic_params_huion_init MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit ff6b548afe4d9d1ff3a0f6ef79e8cbca25d8f905 ] The function performs a check on its input parameters, however, the hdev parameter is used before the check. Initialize the stack variables after checking the input parameters to avoid a possible NULL pointer dereference. Fixes: 9614219e9310e ("HID: uclogic: Extract tablet parameter discovery into a module") Addresses-Coverity-ID: 1443804 ("Null pointer dereference") Signed-off-by: José Expósito Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin --- drivers/hid/hid-uclogic-params.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c index 3a83e2c39b4f..4136837e4d15 100644 --- a/drivers/hid/hid-uclogic-params.c +++ b/drivers/hid/hid-uclogic-params.c @@ -709,9 +709,9 @@ static int uclogic_params_huion_init(struct uclogic_params *params, struct hid_device *hdev) { int rc; - struct usb_device *udev = hid_to_usb_dev(hdev); - struct usb_interface *iface = to_usb_interface(hdev->dev.parent); - __u8 bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber; + struct usb_device *udev; + struct usb_interface *iface; + __u8 bInterfaceNumber; bool found; /* The resulting parameters (noop) */ struct uclogic_params p = {0, }; @@ -725,6 +725,10 @@ static int uclogic_params_huion_init(struct uclogic_params *params, goto cleanup; } + udev = hid_to_usb_dev(hdev); + iface = to_usb_interface(hdev->dev.parent); + bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber; + /* If it's not a pen interface */ if (bInterfaceNumber != 0) { /* TODO: Consider marking the interface invalid */