[PATCH 2/2] HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove()

[Zhang Lixu <lixu.zhang@intel.com>]

The system can experience a random crash a few minutes after the driver is
removed. This issue occurs due to improper handling of memory freeing in
the ishtp_hid_remove() function.

The function currently frees the `driver_data` directly within the loop
that destroys the HID devices, which can lead to accessing freed memory.
Specifically, `hid_destroy_device()` uses `driver_data` when it calls
`hid_ishtp_set_feature()` to power off the sensor, so freeing
`driver_data` beforehand can result in accessing invalid memory.

This patch resolves the issue by storing the `driver_data` in a temporary
variable before calling `hid_destroy_device()`, and then freeing the
`driver_data` after the device is destroyed.

Fixes: 0b28cb4bcb17 ("HID: intel-ish-hid: ISH HID client driver")
Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/intel-ish-hid/ishtp-hid.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/intel-ish-hid/ishtp-hid.c b/drivers/hid/intel-ish-hid/ishtp-hid.c
index 00c6f0ebf356..be2c62fc8251 100644
--- a/drivers/hid/intel-ish-hid/ishtp-hid.c
+++ b/drivers/hid/intel-ish-hid/ishtp-hid.c
@@ -261,12 +261,14 @@ int ishtp_hid_probe(unsigned int cur_hid_dev,
  */
 void ishtp_hid_remove(struct ishtp_cl_data *client_data)
 {
+	void *data;
 	int i;
 
 	for (i = 0; i < client_data->num_hid_devices; ++i) {
 		if (client_data->hid_sensor_hubs[i]) {
-			kfree(client_data->hid_sensor_hubs[i]->driver_data);
+			data = client_data->hid_sensor_hubs[i]->driver_data;
 			hid_destroy_device(client_data->hid_sensor_hubs[i]);
+			kfree(data);
 			client_data->hid_sensor_hubs[i] = NULL;
 		}
 	}
-- 
2.43.0