[PATCH 5.4 108/320] HID: hid-uclogic-params: Invalid parameter check in uclogic_params_init

Greg Kroah-Hartman
2022-01-24T20:10:50Z

From: José Expósito <jose.exposito89@gmail.com>

[ Upstream commit f364c571a5c77e96de2d32062ff019d6b8d2e2bc ]

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: 1443831 ("Null pointer dereference")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-uclogic-params.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c
index ed4ede52b017f..0afd368115891 100644
--- a/drivers/hid/hid-uclogic-params.c
+++ b/drivers/hid/hid-uclogic-params.c
@@ -832,10 +832,10 @@ int uclogic_params_init(struct uclogic_params *params,
struct hid_device *hdev)
{
int rc;
- struct usb_device *udev = hid_to_usb_dev(hdev);
- __u8 bNumInterfaces = udev->config->desc.bNumInterfaces;
- struct usb_interface *iface = to_usb_interface(hdev->dev.parent);
- __u8 bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
+ struct usb_device *udev;
+ __u8 bNumInterfaces;
+ struct usb_interface *iface;
+ __u8 bInterfaceNumber;
bool found;
/* The resulting parameters (noop) */
struct uclogic_params p = {0, };
@@ -846,6 +846,11 @@ int uclogic_params_init(struct uclogic_params *params,
goto cleanup;
}

+ udev = hid_to_usb_dev(hdev);
+ bNumInterfaces = udev->config->desc.bNumInterfaces;
+ iface = to_usb_interface(hdev->dev.parent);
+ bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
+
/*
* Set replacement report descriptor if the original matches the
* specified size. Otherwise keep interface unchanged.
--
2.34.1