[PATCH net v2] net: usb: catc: enable basic endpoint checking

[Ziyi Guo]

catc_probe() fills three URBs with hardcoded endpoint pipes without
verifying the endpoint descriptors:

  - usb_sndbulkpipe(usbdev, 1) and usb_rcvbulkpipe(usbdev, 1) for TX/RX
  - usb_rcvintpipe(usbdev, 2) for interrupt status

A malformed USB device can present these endpoints with transfer types
that differ from what the driver assumes.

Add a catc_usb_ep enum for endpoint numbers, replacing magic constants
throughout. Add usb_check_bulk_endpoints() and usb_check_int_endpoints()
calls after usb_set_interface() to verify endpoint types before use,
rejecting devices with mismatched descriptors at probe time.

Similar to
- commit 90b7f2961798 ("net: usb: rtl8150: enable basic endpoint checking")
which fixed the issue in rtl8150.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Suggested-by: Simon Horman <horms@xxxxxxxxxx>
Signed-off-by: Ziyi Guo <n7l8m4@xxxxxxxxxxxxxxxxxx>
---
v2:
 - Use an enum instead of the magic numbers

 drivers/net/usb/catc.c | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/catc.c b/drivers/net/usb/catc.c
index 6759388692f8..632e27ee9101 100644
--- a/drivers/net/usb/catc.c
+++ b/drivers/net/usb/catc.c
@@ -64,6 +64,16 @@ static const char driver_name[] = "catc";
 #define CTRL_QUEUE		16	/* Max control requests in flight (power of two) */
 #define RX_PKT_SZ		1600	/* Max size of receive packet for F5U011 */
 
+/*
+ * USB endpoints.
+ */
+
+enum catc_usb_ep {
+	CATC_USB_EP_CONTROL	= 0,
+	CATC_USB_EP_BULK	= 1,
+	CATC_USB_EP_INT_IN	= 2,
+};
+
 /*
  * Control requests.
  */
@@ -772,6 +782,13 @@ static int catc_probe(struct usb_interface *intf, const struct usb_device_id *id
 	u8 broadcast[ETH_ALEN];
 	u8 *macbuf;
 	int pktsz, ret = -ENOMEM;
+	static const u8 bulk_ep_addr[] = {
+		CATC_USB_EP_BULK | USB_DIR_OUT,
+		CATC_USB_EP_BULK | USB_DIR_IN,
+		0};
+	static const u8 int_ep_addr[] = {
+		CATC_USB_EP_INT_IN | USB_DIR_IN,
+		0};
 
 	macbuf = kmalloc(ETH_ALEN, GFP_KERNEL);
 	if (!macbuf)
@@ -784,6 +801,14 @@ static int catc_probe(struct usb_interface *intf, const struct usb_device_id *id
 		goto fail_mem;
 	}
 
+	/* Verify that all required endpoints are present */
+	if (!usb_check_bulk_endpoints(intf, bulk_ep_addr) ||
+	    !usb_check_int_endpoints(intf, int_ep_addr)) {
+		dev_err(dev, "Missing or invalid endpoints\n");
+		ret = -ENODEV;
+		goto fail_mem;
+	}
+
 	netdev = alloc_etherdev(sizeof(struct catc));
 	if (!netdev)
 		goto fail_mem;
@@ -828,14 +853,14 @@ static int catc_probe(struct usb_interface *intf, const struct usb_device_id *id
 	usb_fill_control_urb(catc->ctrl_urb, usbdev, usb_sndctrlpipe(usbdev, 0),
 		NULL, NULL, 0, catc_ctrl_done, catc);
 
-	usb_fill_bulk_urb(catc->tx_urb, usbdev, usb_sndbulkpipe(usbdev, 1),
-		NULL, 0, catc_tx_done, catc);
+	usb_fill_bulk_urb(catc->tx_urb, usbdev, usb_sndbulkpipe(usbdev, CATC_USB_EP_BULK),
+			  NULL, 0, catc_tx_done, catc);
 
-	usb_fill_bulk_urb(catc->rx_urb, usbdev, usb_rcvbulkpipe(usbdev, 1),
-		catc->rx_buf, pktsz, catc_rx_done, catc);
+	usb_fill_bulk_urb(catc->rx_urb, usbdev, usb_rcvbulkpipe(usbdev, CATC_USB_EP_BULK),
+			  catc->rx_buf, pktsz, catc_rx_done, catc);
 
-	usb_fill_int_urb(catc->irq_urb, usbdev, usb_rcvintpipe(usbdev, 2),
-                catc->irq_buf, 2, catc_irq_done, catc, 1);
+	usb_fill_int_urb(catc->irq_urb, usbdev, usb_rcvintpipe(usbdev, CATC_USB_EP_INT_IN),
+			 catc->irq_buf, 2, catc_irq_done, catc, 1);
 
 	if (!catc->is_f5u011) {
 		u32 *buf;
-- 
2.34.1