USB: correct error handling in cdc-wdm

This patch to cdc-wdm

- checks for partial extra descriptors
- fixes a leak in the error case of probe
- checks for an exact number of endpoints
- adds a clarifying comment

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 34e6108e1d42..0fe434505ac4 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -3,7 +3,7 @@
  *
  * This driver supports USB CDC WCM Device Management.
  *
- * Copyright (c) 2007-2008 Oliver Neukum
+ * Copyright (c) 2007-2009 Oliver Neukum
  *
  * Some code taken from cdc-acm.c
  *
@@ -610,7 +610,7 @@ static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
         if (!buffer)
                 goto out;
 
-        while (buflen > 0) {
+        while (buflen > 2) {
                 if (buffer [1] != USB_DT_CS_INTERFACE) {
                         dev_err(&intf->dev, "skipping garbage\n");
                         goto next_desc;
@@ -646,16 +646,18 @@ next_desc:
         spin_lock_init(&desc->iuspin);
         init_waitqueue_head(&desc->wait);
         desc->wMaxCommand = maxcom;
+        /* this will be expanded and needed in hardware endianness */
         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
         desc->intf = intf;
         INIT_WORK(&desc->rxwork, wdm_rxwork);
 
-        iface = &intf->altsetting[0];
+        rv = -EINVAL;
+        iface = intf->cur_altsetting;
+        if (iface->desc.bNumEndpoints != 1)
+                goto err;
         ep = &iface->endpoint[0].desc;
-        if (!ep || !usb_endpoint_is_int_in(ep)) {
-                rv = -EINVAL;
+        if (!ep || !usb_endpoint_is_int_in(ep))
                 goto err;
-        }
 
         desc->wMaxPacketSize = le16_to_cpu(ep->wMaxPacketSize);
         desc->bMaxPacketSize0 = udev->descriptor.bMaxPacketSize0;
@@ -711,12 +713,19 @@ next_desc:
 
         usb_set_intfdata(intf, desc);
         rv = usb_register_dev(intf, &wdm_class);
-        dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
-                 intf->minor - WDM_MINOR_BASE);
         if (rv < 0)
-                goto err;
+                goto err3;
+        else
+                dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
+                        intf->minor - WDM_MINOR_BASE);
 out:
         return rv;
+err3:
+        usb_set_intfdata(intf, NULL);
+        usb_buffer_free(interface_to_usbdev(desc->intf),
+                        desc->bMaxPacketSize0,
+                        desc->inbuf,
+                        desc->response->transfer_dma);
 err2:
         usb_buffer_free(interface_to_usbdev(desc->intf),
                         desc->wMaxPacketSize,