[PATCH] hid-core: Zero-pad truncated reports

When it detects a truncated report, hid-core emits a warning and then
processes the report as usual.  This is good because it allows buggy
devices to still get data thru to userspace.  However, the missing bytes of
the report should be cleared before processing, otherwise userspace will be
handed partially-uninitialized data.

This fixes Debian tracker bug #330487.

Signed-off-by: Adam Kropelin <akropel1@rochester.rr.com>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Acked-by: Dmitry Torokhov <dtor_core@ameritech.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/usb/input/hid-core.c b/drivers/usb/input/hid-core.c
index 45f3130fadea9f9646a3212bda45bfb4ee2b3775..a3e44ef1df435684b121cfd110bd2e62463921aa 100644 (file)
--- a/drivers/usb/input/hid-core.c
+++ b/drivers/usb/input/hid-core.c
@@ -893,8 +893,10 @@ static int hid_input_report(int type, struct urb *urb, int interrupt, struct pt_
 
        size = ((report->size - 1) >> 3) + 1;
 
-       if (len < size)
+       if (len < size) {
                dbg("report %d is too short, (%d < %d)", report->id, len, size);
+               memset(data + len, 0, size - len);
+       }
 
        if (hid->claimed & HID_CLAIMED_HIDDEV)
                hiddev_report_event(hid, report);