Commit 1b15d2e5 authored Apr 17, 2014 by Kees Cook Committed by Jiri Kosina May 20, 2014

HID: core: fix validation of report id 0



Some drivers use the first HID report in the list instead of using an
index. In these cases, validation uses ID 0, which was supposed to mean
"first known report". This fixes the problem, which was causing at least
the lgff family of devices to stop working since hid_validate_values
was being called with ID 0, but the devices used single numbered IDs
for their reports:

0x05, 0x01,         /*  Usage Page (Desktop),                   */
0x09, 0x05,         /*  Usage (Gamepad),                        */
0xA1, 0x01,         /*  Collection (Application),               */
0xA1, 0x02,         /*      Collection (Logical),               */
0x85, 0x01,         /*          Report ID (1),                  */
...

Cc: stable@vger.kernel.org
Reported-by: Simon Wood <simon@mungewell.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

parent 825747bb

drivers/hid/hid-core.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -842,7 +842,17 @@ struct hid_report hid_validate_values(struct hid_device hid,
		* ->numbered being checked, which may not always be the case when
		* drivers go to access report values.
		*/
		if (id == 0) {
		/*
		* Validating on id 0 means we should examine the first
		* report in the list.
		*/
		report = list_entry(
		hid->report_enum[type].report_list.next,
		struct hid_report, list);
		} else {
		report = hid->report_enum[type].report_id_hash[id];
		}
		if (!report) {
		hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
		return NULL;

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