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

[Nikita Zhandarovich]

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.

[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>
---
P.S. as AR9170_USB_EP_CMD endpoint can switch between bulk and int,
I failed to find a prettier solution to this problem. Will be glad
to hear if there is a better option...

 drivers/net/wireless/ath/carl9170/usb.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/net/wireless/ath/carl9170/usb.c b/drivers/net/wireless/ath/carl9170/usb.c
index c4edf8355941..66d2ad561fd3 100644
--- a/drivers/net/wireless/ath/carl9170/usb.c
+++ b/drivers/net/wireless/ath/carl9170/usb.c
@@ -1069,6 +1069,33 @@ 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))
+			return -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))
+			return -ENODEV;
+	}
+
 	usb_set_intfdata(intf, ar);
 	SET_IEEE80211_DEV(ar->hw, &intf->dev);