Re: [PATCH v2] wifi: carl9170: add a proper sanity check for endpoints

[Christian Lamparter]

On 4/22/24 8:33 PM, Nikita Zhandarovich wrote:
> Syzkaller reports [1] hitting a warning which is caused by presence
> of a wrong endpoint type at the URB sumbitting stage. While there
> was a check for a specific 4th endpoint, since it can switch types
> between bulk and interrupt, other endpoints are trusted implicitly.
> Similar warning is triggered in a couple of other syzbot issues [2].
>
> Fix the issue by doing a comprehensive check of all endpoints
> taking into account difference between high- and full-speed
> configuration.
>
> This patch has not been tested on real hardware.

Oh, I've tested the original patch on real hardware ;). You can remove that line.

USB: 0846:9010 NetGear, Inc. WNDA3100v1 802.11abgn [Atheros AR9170+AR9104]
USB: 0CF3:1002 Atheros Communications, Inc. TP-Link TL-WN821N v2 / TL-WN822N v1 802.11n [Atheros AR9170]

With both high- and full-speed configuration on two different hcds.
In both cases the driver works the same as before and the interface comes up.

I can retest this patch tomorrow/saturday in case you want to wait around.

But I don't "see" how this can go wrong.

Acked-By: Christian Lamparter <chunkeey@xxxxxxxxx>

I assume the "Reported-and-tested" means that syzbot has verified that with
this patch, it can no longer get the USB-core to throw a warning, right?
<https://syzkaller.appspot.com/bug?extid=e394db78ae0b0032cb4d> says under
"Last patch testing requests) that it tested on the 2024/04/17 and the result
was "error OK"? )

Cheers,
Christian

> [1] Syzkaller report:
> ...
> WARNING: CPU: 0 PID: 4721 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
> ...
> Call Trace:
>   <TASK>
>   carl9170_usb_send_rx_irq_urb+0x273/0x340 drivers/net/wireless/ath/carl9170/usb.c:504
>   carl9170_usb_init_device drivers/net/wireless/ath/carl9170/usb.c:939 [inline]
>   carl9170_usb_firmware_finish drivers/net/wireless/ath/carl9170/usb.c:999 [inline]
>   carl9170_usb_firmware_step2+0x175/0x240 drivers/net/wireless/ath/carl9170/usb.c:1028
>   request_firmware_work_func+0x130/0x240 drivers/base/firmware_loader/main.c:1107
>   process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
>   worker_thread+0x669/0x1090 kernel/workqueue.c:2436
>   kthread+0x2e8/0x3a0 kernel/kthread.c:376
>   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>   </TASK>
>
> [2] Related syzkaller crashes:
> Link: https://syzkaller.appspot.com/bug?extid=e394db78ae0b0032cb4d
> Link: https://syzkaller.appspot.com/bug?extid=9468df99cb63a4a4c4e1
>
> Reported-and-tested-by: syzbot+0ae4804973be759fa420@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: a84fab3cbfdc ("carl9170: 802.11 rx/tx processing and usb backend")
> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
> ---
> v2: as Christian Lamparter <chunkeey@xxxxxxxxx> was kind to point out,
> before returning with error, make sure to free previously allocated
> 'ar' with carl9170_free(ar).
>
>   drivers/net/wireless/ath/carl9170/usb.c | 32 ++++++++++++++++++++++++++++++++
>   1 file changed, 32 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
> index c4edf8355941..a3e03580cd9f 100644
> --- a/drivers/net/wireless/ath/carl9170/usb.c
> +++ b/drivers/net/wireless/ath/carl9170/usb.c
> @@ -1069,6 +1069,38 @@ static int carl9170_usb_probe(struct usb_interface *intf,
>   			ar->usb_ep_cmd_is_bulk = true;
>   	}
>   
> +	/* Verify that all expected endpoints are present */
> +	if (ar->usb_ep_cmd_is_bulk) {
> +		u8 bulk_ep_addr[] = {
> +			AR9170_USB_EP_RX | USB_DIR_IN,
> +			AR9170_USB_EP_TX | USB_DIR_OUT,
> +			AR9170_USB_EP_CMD | USB_DIR_OUT,
> +			0};
> +		u8 int_ep_addr[] = {
> +			AR9170_USB_EP_IRQ | USB_DIR_IN,
> +			0};
> +		if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
> +		    !usb_check_int_endpoints(intf, int_ep_addr))
> +			err = -ENODEV;
> +	} else {
> +		u8 bulk_ep_addr[] = {
> +			AR9170_USB_EP_RX | USB_DIR_IN,
> +			AR9170_USB_EP_TX | USB_DIR_OUT,
> +			0};
> +		u8 int_ep_addr[] = {
> +			AR9170_USB_EP_IRQ | USB_DIR_IN,
> +			AR9170_USB_EP_CMD | USB_DIR_OUT,
> +			0};
> +		if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
> +		    !usb_check_int_endpoints(intf, int_ep_addr))
> +			err = -ENODEV;
> +	}
> +
> +	if (err) {
> +		carl9170_free(ar);
> +		return err;
> +	}
> +
>   	usb_set_intfdata(intf, ar);
>   	SET_IEEE80211_DEV(ar->hw, &intf->dev);
>