4.20-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Torokhov dmitry.torokhov@gmail.com
commit d77651a227f8920dd7ec179b84e400cce844eeb3 upstream.
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: Kyungtae Kim kt0755@gmail.com Reviewed-by: Peter Hutterer peter.hutterer@who-t.net Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/input/misc/uinput.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -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 *ino 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(struc 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);