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Subject[PATCH RFT] can: mcba_usb: properly check endpoint type
Date
Syzbot reported warning in usb_submit_urb() which is caused by wrong
endpoint type. We should check that in endpoint is actually present to
prevent this warning

Fail log:

usb 5-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 1 PID: 49 at drivers/usb/core/urb.c:502 usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
Modules linked in:
CPU: 1 PID: 49 Comm: kworker/1:2 Not tainted 5.17.0-rc6-syzkaller-00184-g38f80f42147f #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed2/0x18a0 drivers/usb/core/urb.c:502
...
Call Trace:
<TASK>
mcba_usb_start drivers/net/can/usb/mcba_usb.c:662 [inline]
mcba_usb_probe+0x8a3/0xc50 drivers/net/can/usb/mcba_usb.c:858
usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:517 [inline]

Reported-and-tested-by: syzbot+3bc1dce0cc0052d60fde@syzkaller.appspotmail.com
Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---

Meta comments:

I am not an usb expert, but looks like this driver uses one
endpoint for in and out transactions:

/* MCBA endpoint numbers */
#define MCBA_USB_EP_IN 1
#define MCBA_USB_EP_OUT 1

That's why check only for in endpoint is added

---
drivers/net/can/usb/mcba_usb.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c
index 77bddff86252..646aac1a8684 100644
--- a/drivers/net/can/usb/mcba_usb.c
+++ b/drivers/net/can/usb/mcba_usb.c
@@ -807,6 +807,13 @@ static int mcba_usb_probe(struct usb_interface *intf,
struct mcba_priv *priv;
int err;
struct usb_device *usbdev = interface_to_usbdev(intf);
+ struct usb_endpoint_descriptor *in;
+
+ err = usb_find_common_endpoints(intf->cur_altsetting, &in, NULL, NULL, NULL);
+ if (err) {
+ dev_err(&intf->dev, "Can't find endpoints\n");
+ return -ENODEV;
+ }

netdev = alloc_candev(sizeof(struct mcba_priv), MCBA_MAX_TX_URBS);
if (!netdev) {
--
2.35.1
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