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;
Content-Type: text/plain; charset="UTF-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Sean Young" <sean@mess.org>,
        "Mauro Carvalho Chehab" <mchehab@s-opensource.com>
Date:   Sun, 11 Feb 2018 04:20:06 +0000
Message-ID: <lsq.1518322806.549326819@decadent.org.uk>
Subject: [PATCH 3.2 07/79] media: rc: check for integer overflow
In-Reply-To: <lsq.1518322802.943358572@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.2.99-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Sean Young <sean@mess.org>

commit 3e45067f94bbd61dec0619b1c32744eb0de480c8 upstream.

The ioctl LIRC_SET_REC_TIMEOUT would set a timeout of 704ns if called
with a timeout of 4294968us.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
[bwh: Backported to 3.2: open-code U32_MAX]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/media/rc/ir-lirc-codec.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/media/rc/ir-lirc-codec.c
+++ b/drivers/media/rc/ir-lirc-codec.c
@@ -255,11 +255,14 @@ static long ir_lirc_ioctl(struct file *f
 		if (!dev->max_timeout)
 			return -ENOSYS;
 
+		/* Check for multiply overflow */
+		if (val > (u32)(-1) / 1000)
+			return -EINVAL;
+
 		tmp = val * 1000;
 
-		if (tmp < dev->min_timeout ||
-		    tmp > dev->max_timeout)
-				return -EINVAL;
+		if (tmp < dev->min_timeout || tmp > dev->max_timeout)
+			return -EINVAL;
 
 		dev->timeout = tmp;
 		break;