[PATCH 1/2] usb: ehci: Prevent possible modulo by zero

Khalid Masum
2022-08-23T19:34:59Z

usb_maxpacket() returns 0 if it fails to fetch the endpoint. This
value is later used for calculating modulo. Which can cause modulo
by zero in qtd_fill and qh_urb_transaction.

Prevent this breakage by returning if maxpacket is found to be 0.

Fixes coverity warning: 744857 ("Division or modulo by zero")
Signed-off-by: Khalid Masum <khalid.masum.92@gmail.com>
---
drivers/usb/host/ehci-q.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 807e64991e3e..eb31d13e9ecd 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -646,6 +646,8 @@ qh_urb_transaction (
/* else it's already initted to "out" pid (0 << 8) */

maxpacket = usb_maxpacket(urb->dev, urb->pipe);
+ if (unlikely(!maxpacket))
+ return NULL;

/*
* buffer gets wrapped in one or more qtds;
--
2.37.1