HID: logitech-dj: prevent false errors to be shown

Commit "HID: logitech: perform bounds checking on device_id early
enough" unfortunately leaks some errors to dmesg which are not real
ones:
- if the report is not a DJ one, then there is not point in checking
  the device_id
- the receiver (index 0) can also receive some notifications which
  can be safely ignored given the current implementation

Move out the test regarding the report_id and also discards
printing errors when the receiver got notified.

Fixes: ad3e14d7c5268c2e24477c6ef54bbdf88add5d36
Cc: stable@vger.kernel.org
Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index b7ba82960c7925c5d04eb898af55a95b3be058f4..9bf8637747a57f1b362680eeb36faf649b35f2fd 100644 (file)
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -656,7 +656,6 @@ static int logi_dj_raw_event(struct hid_device *hdev,
        struct dj_receiver_dev *djrcv_dev = hid_get_drvdata(hdev);
        struct dj_report *dj_report = (struct dj_report *) data;
        unsigned long flags;
-       bool report_processed = false;
 
        dbg_hid("%s, size:%d\n", __func__, size);
 
@@ -683,34 +682,42 @@ static int logi_dj_raw_event(struct hid_device *hdev,
         * device (via hid_input_report() ) and return 1 so hid-core does not do
         * anything else with it.
         */
+
+       /* case 1) */
+       if (data[0] != REPORT_ID_DJ_SHORT)
+               return false;
+
        if ((dj_report->device_index < DJ_DEVICE_INDEX_MIN) ||
            (dj_report->device_index > DJ_DEVICE_INDEX_MAX)) {
-               dev_err(&hdev->dev, "%s: invalid device index:%d\n",
+               /*
+                * Device index is wrong, bail out.
+                * This driver can ignore safely the receiver notifications,
+                * so ignore those reports too.
+                */
+               if (dj_report->device_index != DJ_RECEIVER_INDEX)
+                       dev_err(&hdev->dev, "%s: invalid device index:%d\n",
                                __func__, dj_report->device_index);
                return false;
        }
 
        spin_lock_irqsave(&djrcv_dev->lock, flags);
-       if (dj_report->report_id == REPORT_ID_DJ_SHORT) {
-               switch (dj_report->report_type) {
-               case REPORT_TYPE_NOTIF_DEVICE_PAIRED:
-               case REPORT_TYPE_NOTIF_DEVICE_UNPAIRED:
-                       logi_dj_recv_queue_notification(djrcv_dev, dj_report);
-                       break;
-               case REPORT_TYPE_NOTIF_CONNECTION_STATUS:
-                       if (dj_report->report_params[CONNECTION_STATUS_PARAM_STATUS] ==
-                           STATUS_LINKLOSS) {
-                               logi_dj_recv_forward_null_report(djrcv_dev, dj_report);
-                       }
-                       break;
-               default:
-                       logi_dj_recv_forward_report(djrcv_dev, dj_report);
+       switch (dj_report->report_type) {
+       case REPORT_TYPE_NOTIF_DEVICE_PAIRED:
+       case REPORT_TYPE_NOTIF_DEVICE_UNPAIRED:
+               logi_dj_recv_queue_notification(djrcv_dev, dj_report);
+               break;
+       case REPORT_TYPE_NOTIF_CONNECTION_STATUS:
+               if (dj_report->report_params[CONNECTION_STATUS_PARAM_STATUS] ==
+                   STATUS_LINKLOSS) {
+                       logi_dj_recv_forward_null_report(djrcv_dev, dj_report);
                }
-               report_processed = true;
+               break;
+       default:
+               logi_dj_recv_forward_report(djrcv_dev, dj_report);
        }
        spin_unlock_irqrestore(&djrcv_dev->lock, flags);
 
-       return report_processed;
+       return true;
 }
 
 static int logi_dj_probe(struct hid_device *hdev,

diff --git a/drivers/hid/hid-logitech-dj.h b/drivers/hid/hid-logitech-dj.h
index 4a4000340ce1ed8cf6be1f81ee8e0f21d8ba5f5a..daeb0aa4bee99a60f3391c0ab4a56803b37a2568 100644 (file)
--- a/drivers/hid/hid-logitech-dj.h
+++ b/drivers/hid/hid-logitech-dj.h
@@ -27,6 +27,7 @@
 
 #define DJ_MAX_PAIRED_DEVICES                  6
 #define DJ_MAX_NUMBER_NOTIFICATIONS            8
+#define DJ_RECEIVER_INDEX                      0
 #define DJ_DEVICE_INDEX_MIN                    1
 #define DJ_DEVICE_INDEX_MAX                    6