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Commit d77651a2 authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: uinput - fix undefined behavior in uinput_validate_absinfo() 



An integer overflow may arise in uinput_validate_absinfo() if "max - min"
can't be represented by an "int". We should check for overflow before
trying to use the result.

Reported-by: default avatarKyungtae Kim <kt0755@gmail.com>
Reviewed-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 3eb66e91

drivers/input/misc/uinput.c

+3 −2
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <linux/init.h>

#include <linux/fs.h>

#include <linux/miscdevice.h>

#include <linux/overflow.h>

#include <linux/input/mt.h>

#include "../input-compat.h"
@@ -405,7 +406,7 @@ static int uinput_open(struct inode *inode, struct file *file) 
static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,

				   const struct input_absinfo *abs)

{

	int min, max;

	int min, max, range;



	min = abs->minimum;

	max = abs->maximum;
@@ -417,7 +418,7 @@ static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code, 
		return -EINVAL;

	}



	if (abs->flat > max - min) {

	if (!check_sub_overflow(max, min, &range) && abs->flat > range) {

		printk(KERN_DEBUG

		       "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n",

		       UINPUT_NAME, code, abs->flat, min, max);