HID: validate feature and input report details

commit cc6b54aa54bf40b762cab45a9fc8aa81653146eb upstream.

When dealing with usage_index, be sure to properly use unsigned instead of
int to avoid overflows.

When working on report fields, always validate that their report_counts are
in bounds.
Without this, a HID device could report a malicious feature report that
could trick the driver into a heap overflow:

[  634.885003] usb 1-1: New USB device found, idVendor=0596, idProduct=0500
...
[  676.469629] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten

CVE-2013-2897

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
[bwh: Backported to 3.2:
 - Drop inapplicable changes to hid_usage::usage_index initialisation and
   to hid_report_raw_event()
 - Adjust context in report_features()
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>