Commit 1cc1cc92 authored Jun 19, 2015 by Brent Adam Committed by Jiri Kosina Jul 08, 2015

HID: multitouch: Fix fields from pen report ID being interpreted for multitouch



Fields like HID_DG_CONTACTCOUNT are outside of the physical collection,
but within the application collection and report ID.  Make sure to catch
those fields that are not part of the mt_report_id and return 0 so they
can be processed with the pen.  Otherwise, the wrong HID_DG_CONTACTCOUNT
will be applied to cc_index and result in dereferencing a null pointer in
mt_touch_report.

Signed-off-by: Brent Adam <brentadam@smarttech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

parent c5b2b809

drivers/hid/hid-multitouch.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -778,9 +778,16 @@ static int mt_input_mapping(struct hid_device hdev, struct hid_input hi,
		/*
		* some egalax touchscreens have "application == HID_DG_TOUCHSCREEN"
		* for the stylus.
		* The check for mt_report_id ensures we don't process
		* HID_DG_CONTACTCOUNT from the pen report as it is outside the physical
		* collection, but within the report ID.
		*/
		if (field->physical == HID_DG_STYLUS)
		return 0;
		else if ((field->physical == 0) &&
		(field->report->id != td->mt_report_id) &&
		(td->mt_report_id != -1))
		return 0;

		if (field->application == HID_DG_TOUCHSCREEN \|\|
		field->application == HID_DG_TOUCHPAD)