From d77651a227f8920dd7ec179b84e400cce844eeb3 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 14 Jan 2019 13:54:55 -0800 Subject: [PATCH] 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: Kyungtae Kim Reviewed-by: Peter Hutterer Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov --- drivers/input/misc/uinput.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e8688b..26ec603fe220 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #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);