[PATCH 5.10 011/132] HID: wacom: fix problems when device is not a valid USB device

Greg Kroah-Hartman
2021-12-13T09:53:36Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 720ac467204a70308bd687927ed475afb904e11b upstream.

The wacom driver accepts devices of more than just USB types, but some
code paths can cause problems if the device being controlled is not a
USB device due to a lack of checking. Add the needed checks to ensure
that the USB device accesses are only happening on a "real" USB device,
and not one on some other bus.

Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Cc: stable@vger.kernel.org
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211201183503.2373082-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/wacom_sys.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -726,7 +726,7 @@ static void wacom_retrieve_hid_descripto
* Skip the query for this type and modify defaults based on
* interface number.
*/
- if (features->type == WIRELESS) {
+ if (features->type == WIRELESS && intf) {
if (intf->cur_altsetting->desc.bInterfaceNumber == 0)
features->device_type = WACOM_DEVICETYPE_WL_MONITOR;
else
@@ -2448,6 +2448,9 @@ static void wacom_wireless_work(struct w

wacom_destroy_battery(wacom);

+ if (!usbdev)
+ return;
+
/* Stylus interface */
hdev1 = usb_get_intfdata(usbdev->config->interface[1]);
wacom1 = hid_get_drvdata(hdev1);
@@ -2727,8 +2730,6 @@ static void wacom_mode_change_work(struc
static int wacom_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
- struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
- struct usb_device *dev = interface_to_usbdev(intf);
struct wacom *wacom;
struct wacom_wac *wacom_wac;
struct wacom_features *features;
@@ -2763,8 +2764,14 @@ static int wacom_probe(struct hid_device
wacom_wac->hid_data.inputmode = -1;
wacom_wac->mode_report = -1;

- wacom->usbdev = dev;
- wacom->intf = intf;
+ if (hid_is_usb(hdev)) {
+ struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+ struct usb_device *dev = interface_to_usbdev(intf);
+
+ wacom->usbdev = dev;
+ wacom->intf = intf;
+ }
+
mutex_init(&wacom->lock);
INIT_DELAYED_WORK(&wacom->init_work, wacom_init_work);
INIT_WORK(&wacom->wireless_work, wacom_wireless_work);