[PATCH 5.4 109/320] HID: hid-uclogic-params: Invalid parameter check in uclogic_params_get_str_desc

Greg Kroah-Hartman
2022-01-24T19:32:37Z

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

[ Upstream commit 0a94131d6920916ccb6a357037c535533af08819 ]

The function performs a check on the hdev input parameters, however, it
is used before the check.

Initialize the udev variable after the sanity check to avoid a
possible NULL pointer dereference.

Fixes: 9614219e9310e ("HID: uclogic: Extract tablet parameter discovery into a module")
Addresses-Coverity-ID: 1443827 ("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 | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-uclogic-params.c b/drivers/hid/hid-uclogic-params.c
index 0afd368115891..1f3ea6c93ef44 100644
--- a/drivers/hid/hid-uclogic-params.c
+++ b/drivers/hid/hid-uclogic-params.c
@@ -65,7 +65,7 @@ static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
__u8 idx, size_t len)
{
int rc;
- struct usb_device *udev = hid_to_usb_dev(hdev);
+ struct usb_device *udev;
__u8 *buf = NULL;

/* Check arguments */
@@ -74,6 +74,8 @@ static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
goto cleanup;
}

+ udev = hid_to_usb_dev(hdev);
+
buf = kmalloc(len, GFP_KERNEL);
if (buf == NULL) {
rc = -ENOMEM;
--
2.34.1