HID: sensor-hub: validate feature report details

A HID device could send a malicious feature report that would cause the
sensor-hub HID driver to read past the end of heap allocation, leaking
kernel memory contents to the caller.

CVE-2013-2898

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@kernel.org
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-sensor-hub.c

@@ -221,7 +221,8 @@ int sensor_hub_get_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
 
 	mutex_lock(&data->mutex);
 	report = sensor_hub_report(report_id, hsdev->hdev, HID_FEATURE_REPORT);
-	if (!report || (field_index >=  report->maxfield)) {
+	if (!report || (field_index >=  report->maxfield) ||
+	    report->field[field_index]->report_count < 1) {
 		ret = -EINVAL;
 		goto done_proc;
 	}