From f364c571a5c77e96de2d32062ff019d6b8d2e2bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= <jose.exposito89@gmail.com>
Date: Wed, 5 Jan 2022 18:29:12 +0100
Subject: [PATCH] HID: hid-uclogic-params: Invalid parameter check in uclogic_params_init
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Git-commit: f364c571a5c77e96de2d32062ff019d6b8d2e2bc
Patch-mainline: v5.17-rc1
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 adff1bd68d9f..3c10b858cf74 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.
--
2.31.1