From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Date: Wed, 11 Apr 2018 15:47:32 +0000 (-0400)
Subject: media: v4l2-compat-ioctl32: prevent go past max size
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=06b846486668e1de1d350f8adc86c3d36f01a4ac;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

media: v4l2-compat-ioctl32: prevent go past max size

commit ea72fbf588ac9c017224dcdaa2019ff52ca56fee upstream.

As warned by smatch:
	drivers/media/v4l2-core/v4l2-compat-ioctl32.c:879 put_v4l2_ext_controls32() warn: check for integer overflow 'count'

The access_ok() logic should check for too big arrays too.

Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 6730fd08ef03..e159dfc21279 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -871,7 +871,7 @@ static int put_v4l2_ext_controls32(struct file *file,
 	    get_user(kcontrols, &kp->controls))
 		return -EFAULT;
 
-	if (!count)
+	if (!count || count > (U32_MAX/sizeof(*ucontrols)))
 		return 0;
 	if (get_user(p, &up->controls))
 		return -EFAULT;