[PATCH v4] HID:hid-sensor-custom: Fix buffer overrun in device name

[Todd Brandt]

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 <todd.e.brandt@xxxxxxxxxxxxxxx>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217169
Fixes: 98c062e82451 ("HID: hid-sensor-custom: Allow more custom iio sensors")
Cc: stable@xxxxxxxxxxxxxxx
Suggested-by: Philipp Jungkamp <p.jungkamp@xxxxxxx>
Signed-off-by: Philipp Jungkamp <p.jungkamp@xxxxxxx>
Signed-off-by: Todd Brandt <todd.e.brandt@xxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
Changes in v4:
- add the Fixes line
- add patch version change list
Changes in v3:
- update the changelog
- add proper reviewed/signed/suggested links
Changes in v2:
- update the changelog

 drivers/hid/hid-sensor-custom.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
index 3e3f89e01d81..d85398721659 100644
--- a/drivers/hid/hid-sensor-custom.c
+++ b/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;
-- 
2.17.1