HID: hid-sensor-custom: Fix buffer overrun in device name

On some platforms there are some platform devices created with
invalid names. For example: "HID-SENSOR-INT-020b?.39.auto" instead
of "HID-SENSOR-INT-020b.39.auto"

This string include some invalid characters, hence it will fail to
properly load the driver which will handle this custom sensor. Also
it is a problem for some user space tools, which parses the device
names from ftrace and dmesg.

This is because the string, real_usage, is not NULL terminated and
printed with %s to form device name.

To address this, initialize the real_usage string with 0s.

Reported-and-tested-by: Todd Brandt <[email protected]>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217169
Fixes: 98c062e ("HID: hid-sensor-custom: Allow more custom iio sensors")
Cc: [email protected]
Suggested-by: Philipp Jungkamp <[email protected]>
Signed-off-by: Philipp Jungkamp <[email protected]>
Signed-off-by: Todd Brandt <[email protected]>
Reviewed-by: Andi Shyti <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Acked-by: Srinivas Pandruvada <[email protected]>
Signed-off-by: Jiri Kosina <[email protected]>

Author: tebrandt

drivers/hid/hid-sensor-custom.c

@@ -940,7 +940,7 @@ hid_sensor_register_platform_device(struct platform_device *pdev,
 				    struct hid_sensor_hub_device *hsdev,
 				    const struct hid_sensor_custom_match *match)
 {
-	char real_usage[HID_SENSOR_USAGE_LENGTH];
+	char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 };
 	struct platform_device *custom_pdev;
 	const char *dev_name;
 	char *c;