[3.13.y.z extended stable] Patch "HID: logitech-dj: prevent false errors to be shown" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d511f39e96d2e52851ea8f80ca7f4464206c5b82 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires at redhat.com>
Date: Fri, 22 Aug 2014 16:16:05 -0400
Subject: HID: logitech-dj: prevent false errors to be shown

commit 5abfe85c1d4694d5d4bbd13ecc166262b937adf0 upstream.

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

Reported-and-tested-by: Markus Trippelsdorf <markus at trippelsdorf.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires at redhat.com>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/hid/hid-logitech-dj.c | 43 +++++++++++++++++++++++++------------------
 drivers/hid/hid-logitech-dj.h |  1 +
 2 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index e19efd6..fa1da91 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -679,7 +679,6 @@ 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);

@@ -706,34 +705,42 @@ 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 4a40003..daeb0aa 100644
--- 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

--
1.9.1