Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Mauro Carvalho Chehab <mchehab@s-opensource.com>
Subject: [PATCH 4.4 087/105] media: v4l2-compat-ioctl32: prevent go past max size
Date:   Sun,  1 Jul 2018 18:02:37 +0200
Message-Id: <20180701153155.678978356@linuxfoundation.org>
In-Reply-To: <20180701153149.382300170@linuxfoundation.org>
References: <20180701153149.382300170@linuxfoundation.org>
User-Agent: quilt/0.65
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mauro Carvalho Chehab <mchehab@s-opensource.com>

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>

---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -864,7 +864,7 @@ static int put_v4l2_ext_controls32(struc
 	    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;