[PATCH] Input: uinput - fix undefined behavior in uinput_validate_absinfo()
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STALE2832d
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2019-01-14 22:04:57
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Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
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 <redacted> Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> --- 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 <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);
--
2.20.1.97.g81188d93c3-goog
--
Dmitry