From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: [PATCH] Input: uinput - fix undefined behavior in uinput_validate_absinfo() Date: Mon, 14 Jan 2019 14:04:48 -0800 Message-ID: <20190114220448.GA241112@dtor-ws> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: linux-input@vger.kernel.org Cc: Byoungyoung Lee , rydberg@bitmath.org, DaeRyong Jeong , syzkaller@googlegroups.com, Peter Hutterer , linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org 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 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); -- 2.20.1.97.g81188d93c3-goog -- Dmitry