HID: Do not discard truncated input reports

Truncated reports should not be discarded since it prevents buggy
devices from communicating with userspace.

Prior to the regession introduced in 2.6.20, a shorter-than-expected
report in hid_input_report() was passed thru after having the missing
bytes cleared. This behavior was established over a few patches in the
2.6.early-teens days, including commit
cd6104572bca9e4afe0dcdb8ecd65ef90b01297b.

This patch restores the previous behavior and fixes the regression.

Signed-off-by: Adam Kropelin <akropel1@rochester.rr.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 67f3347..1cca32f 100644 (file)
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -969,7 +969,7 @@ int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int i
 
        if (size < rsize) {
                dbg("report %d is too short, (%d < %d)", report->id, size, rsize);
-               return -1;
+               memset(data + size, 0, rsize - size);
        }
 
        if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)