[PATCH 3.2 07/79] media: rc: check for integer overflow

Ben Hutchings
2018-02-11T04:33:40Z

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;