From: José Expósito <jose.exposito89@gmail.com>
Date: Wed, 5 Jan 2022 17:29:12 +0000 (+0100)
Subject: HID: hid-uclogic-params: Invalid parameter check in uclogic_params_init
X-Git-Tag: accepted/tizen/unified/20230118.172025~3384
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=621aade97324398e74e8cd921fc02fc015e1d606;p=platform%2Fkernel%2Flinux-rpi.git

HID: hid-uclogic-params: Invalid parameter check in uclogic_params_init

[ 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>
---

diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c
index adff1bd..3c10b85 100644
--- a/drivers/hid/hid-uclogic-params.c
+++ b/drivers/hid/hid-uclogic-params.c
@@ -834,10 +834,10 @@ 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, };
@@ -848,6 +848,11 @@ 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.