usb: usb_get_configuration() obeys authorization

If called and the device is not authorized to be used, then we don't
allow reading the configurations.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/config.c

@@ -507,18 +507,30 @@ void usb_destroy_configuration(struct usb_device *dev)
 }
 
 
-// hub-only!! ... and only in reset path, or usb_new_device()
-// (used by real hubs and virtual root hubs)
+/*
+ * Get the USB config descriptors, cache and parse'em
+ *
+ * hub-only!! ... and only in reset path, or usb_new_device()
+ * (used by real hubs and virtual root hubs)
+ *
+ * NOTE: if this is a WUSB device and is not authorized, we skip the
+ *       whole thing. A non-authorized USB device has no
+ *       configurations.
+ */
 int usb_get_configuration(struct usb_device *dev)
 {
 	struct device *ddev = &dev->dev;
 	int ncfg = dev->descriptor.bNumConfigurations;
-	int result = -ENOMEM;
+	int result = 0;
 	unsigned int cfgno, length;
 	unsigned char *buffer;
 	unsigned char *bigbuffer;
  	struct usb_config_descriptor *desc;
 
+	cfgno = 0;
+	if (dev->authorized == 0)	/* Not really an error */
+		goto out_not_authorized;
+	result = -ENOMEM;
 	if (ncfg > USB_MAXCONFIG) {
 		dev_warn(ddev, "too many configurations: %d, "
 		    "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
@@ -545,14 +557,15 @@ int usb_get_configuration(struct usb_device *dev)
 		goto err2;
 	desc = (struct usb_config_descriptor *)buffer;
 
-	for (cfgno = 0; cfgno < ncfg; cfgno++) {
+	result = 0;
+	for (; cfgno < ncfg; cfgno++) {
 		/* We grab just the first descriptor so we know how long
 		 * the whole configuration is */
 		result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 		    buffer, USB_DT_CONFIG_SIZE);
 		if (result < 0) {
 			dev_err(ddev, "unable to read config index %d "
-			    "descriptor/%s\n", cfgno, "start");
+			    "descriptor/%s: %d\n", cfgno, "start", result);
 			dev_err(ddev, "chopping to %d config(s)\n", cfgno);
 			dev->descriptor.bNumConfigurations = cfgno;
 			break;
@@ -599,6 +612,7 @@ int usb_get_configuration(struct usb_device *dev)
 
 err:
 	kfree(buffer);
+out_not_authorized:
 	dev->descriptor.bNumConfigurations = cfgno;
 err2:
 	if (result == -ENOMEM)