[PATCH v4] ath9k: verify the expected usb_endpoints are present

[Fedor Pchelkin <pchelkin@ispras.ru>]

The bug arises when a USB device claims to be an ATH9K but doesn't
have the expected endpoints. (In this case there was an interrupt
endpoint where the driver expected a bulk endpoint.) The kernel
needs to be able to handle such devices without getting an internal error.

usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 3 PID: 500 at drivers/usb/core/urb.c:493 usb_submit_urb+0xce2/0x1430 drivers/usb/core/urb.c:493
Modules linked in:
CPU: 3 PID: 500 Comm: kworker/3:2 Not tainted 5.10.135-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Workqueue: events request_firmware_work_func
RIP: 0010:usb_submit_urb+0xce2/0x1430 drivers/usb/core/urb.c:493
Call Trace:
 ath9k_hif_usb_alloc_rx_urbs drivers/net/wireless/ath/ath9k/hif_usb.c:908 [inline]
 ath9k_hif_usb_alloc_urbs+0x75e/0x1010 drivers/net/wireless/ath/ath9k/hif_usb.c:1019
 ath9k_hif_usb_dev_init drivers/net/wireless/ath/ath9k/hif_usb.c:1109 [inline]
 ath9k_hif_usb_firmware_cb+0x142/0x530 drivers/net/wireless/ath/ath9k/hif_usb.c:1242
 request_firmware_work_func+0x12e/0x240 drivers/base/firmware_loader/main.c:1097
 process_one_work+0x9af/0x1600 kernel/workqueue.c:2279
 worker_thread+0x61d/0x12f0 kernel/workqueue.c:2425
 kthread+0x3b4/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
v1->v2: use reverse x-mas tree ordering of the variable definitions
v2->v3: fix tab
v3->v4: fix patch apply error

 drivers/net/wireless/ath/ath9k/hif_usb.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 4d9002a9d082..b359a9d382e2 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -1329,10 +1329,24 @@ static int send_eject_command(struct usb_interface *interface)
 static int ath9k_hif_usb_probe(struct usb_interface *interface,
 			       const struct usb_device_id *id)
 {
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out, *int_in, *int_out;
 	struct usb_device *udev = interface_to_usbdev(interface);
+	struct usb_host_interface *alt;
 	struct hif_device_usb *hif_dev;
 	int ret = 0;
 
+	/* Verify the expected endpoints are present */
+	alt = interface->cur_altsetting;
+	if (usb_find_common_endpoints(alt, &bulk_in, &bulk_out, &int_in, &int_out) < 0 ||
+			usb_endpoint_num(bulk_in) != USB_WLAN_RX_PIPE ||
+			usb_endpoint_num(bulk_out) != USB_WLAN_TX_PIPE ||
+			usb_endpoint_num(int_in) != USB_REG_IN_PIPE ||
+			usb_endpoint_num(int_out) != USB_REG_OUT_PIPE) {
+			dev_err(&udev->dev,
+					"ath9k_htc: Device endpoint numbers are not the expected ones\n");
+		return -ENODEV;
+	}
+
 	if (id->driver_info == STORAGE_DEVICE)
 		return send_eject_command(interface);
 
-- 
2.25.1