[PATCH 3.4 26/45] HID: logitech-dj: prevent false errors to be shown

Zefan Li
2014-09-23T02:39:56Z

From: Benjamin Tissoires <benjamin.tissoires@redhat.com>

3.4.104-rc1 review patch. If anyone has any objections, please let me know.

------------------

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@trippelsdorf.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Zefan Li <lizefan@huawei.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 bdf9f53..f009ab2 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -681,7 +681,6 @@ 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);

@@ -708,34 +707,42 @@ 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

--
1.7.9.5