Commit 48d16777 authored by Tomasz Pakuła's avatar Tomasz Pakuła Committed by Jiri Kosina
Browse files

HID: pidff: Fix integer overflow in pidff_rescale 

Rescaling values close to the max (U16_MAX) temporarily creates values
that exceed the s32 range. This caused value overflow in case when, for
example, a periodic effect phase was higer than 180 degrees. In turn,
rescale function could return values outised of the logical range of the
HID field.

Fix by using 64 bit signed integer to store the value during calculation
but still return only 32 bit integer.

Closes: https://github.com/JacKeTUs/universal-pidff/issues/116


Fixes: 224ee88f ("Input: add force feedback driver for PID devices")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent a991aa5e

drivers/hid/usbhid/hid-pidff.c

+5 −2
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include "hid-pidff.h"

#include <linux/hid.h>

#include <linux/input.h>

#include <linux/math64.h>

#include <linux/minmax.h>

#include <linux/slab.h>

#include <linux/stringify.h>
@@ -326,8 +327,10 @@ static s32 pidff_clamp(s32 i, struct hid_field *field) 
 */

static int pidff_rescale(int i, int max, struct hid_field *field)

{

	return i * (field->logical_maximum - field->logical_minimum) / max +

	       field->logical_minimum;

	/* 64 bits needed for big values during rescale */

	s64 result = field->logical_maximum - field->logical_minimum;



	return div_s64(result * i, max) + field->logical_minimum;

}



/*