[4.19,12/52] media: mceusb: sanity check for prescaler value
diff mbox series

Message ID 20210305120854.269375710@linuxfoundation.org
State New, archived
Headers show
Series
  • Untitled series #487861
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Commit Message

Greg KH March 5, 2021, 12:21 p.m. UTC
From: Sean Young <sean@mess.org>

commit 9dec0f48a75e0dadca498002d25ef4e143e60194 upstream.

prescaler larger than 8 would mean the carrier is at most 152Hz,
which does not make sense for IR carriers.

Reported-by: syzbot+6d31bf169a8265204b8d@syzkaller.appspotmail.com
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/media/rc/mceusb.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Patch
diff mbox series

--- a/drivers/media/rc/mceusb.c
+++ b/drivers/media/rc/mceusb.c
@@ -685,11 +685,18 @@  static void mceusb_dev_printdata(struct
 				data[0], data[1]);
 			break;
 		case MCE_RSP_EQIRCFS:
+			if (!data[0] && !data[1]) {
+				dev_dbg(dev, "%s: no carrier", inout);
+				break;
+			}
+			// prescaler should make sense
+			if (data[0] > 8)
+				break;
 			period = DIV_ROUND_CLOSEST((1U << data[0] * 2) *
 						   (data[1] + 1), 10);
 			if (!period)
 				break;
-			carrier = (1000 * 1000) / period;
+			carrier = USEC_PER_SEC / period;
 			dev_dbg(dev, "%s carrier of %u Hz (period %uus)",
 				 inout, carrier, period);
 			break;