usb: introduce usb_authorize/deauthorize()

These USB API functions will do the full authorization/deauthorization
to be used for a device. When authorized we effectively allow a
configuration to be set. Reverse that when deauthorized.

Effectively this means that we have to clean all the configuration
descriptors on deauthorize and reload them when we authorized. We could
do without throwing them out for wired devices, but for wireless, we can
read them only after authenticating, and thus, when authorizing an
authenticated device we would need to read them. So to simplify, always
release them on deauthorize(), re-read them on authorize().

Also fix leak reported by Ragner Magalhaes; in usb_deauthorize_device(),
bNumConfigurations was being set to zero before the for loop, and thus
the different raw descriptors where never being freed.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 81 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 65d9ea1..f725d9e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1399,6 +1399,87 @@ fail:
 	return err;
 }
 
+
+/**
+ * Similar to usb_disconnect()
+ *
+ * We share a lock (that we have) with device_del(), so we need to
+ * defer its call.
+ */
+int usb_deauthorize_device(struct usb_device *usb_dev)
+{
+	unsigned cnt;
+	usb_lock_device(usb_dev);
+	if (usb_dev->authorized == 0)
+		goto out_unauthorized;
+	usb_dev->authorized = 0;
+	usb_set_configuration(usb_dev, -1);
+	usb_dev->product = kstrdup("n/a (unauthorized)", GFP_KERNEL);
+	usb_dev->manufacturer = kstrdup("n/a (unauthorized)", GFP_KERNEL);
+	usb_dev->serial = kstrdup("n/a (unauthorized)", GFP_KERNEL);
+	kfree(usb_dev->config);
+	usb_dev->config = NULL;
+	for (cnt = 0; cnt < usb_dev->descriptor.bNumConfigurations; cnt++)
+		kfree(usb_dev->rawdescriptors[cnt]);
+	usb_dev->descriptor.bNumConfigurations = 0;
+	kfree(usb_dev->rawdescriptors);
+out_unauthorized:
+	usb_unlock_device(usb_dev);
+	return 0;
+}
+
+
+int usb_authorize_device(struct usb_device *usb_dev)
+{
+	int result = 0, c;
+	usb_lock_device(usb_dev);
+	if (usb_dev->authorized == 1)
+		goto out_authorized;
+	kfree(usb_dev->product);
+	usb_dev->product = NULL;
+	kfree(usb_dev->manufacturer);
+	usb_dev->manufacturer = NULL;
+	kfree(usb_dev->serial);
+	usb_dev->serial = NULL;
+	result = usb_autoresume_device(usb_dev);
+	if (result < 0) {
+		dev_err(&usb_dev->dev,
+			"can't autoresume for authorization: %d\n", result);
+		goto error_autoresume;
+	}
+	result = usb_get_device_descriptor(usb_dev, sizeof(usb_dev->descriptor));
+	if (result < 0) {
+		dev_err(&usb_dev->dev, "can't re-read device descriptor for "
+			"authorization: %d\n", result);
+		goto error_device_descriptor;
+	}
+	usb_dev->authorized = 1;
+	result = usb_configure_device(usb_dev);
+	if (result < 0)
+		goto error_configure;
+	/* Choose and set the configuration.  This registers the interfaces
+	 * with the driver core and lets interface drivers bind to them.
+	 */
+	c = choose_configuration(usb_dev);
+	if (c >= 0) {
+		result = usb_set_configuration(usb_dev, c);
+		if (result) {
+			dev_err(&usb_dev->dev,
+				"can't set config #%d, error %d\n", c, result);
+			/* This need not be fatal.  The user can try to
+			 * set other configurations. */
+		}
+	}
+	dev_info(&usb_dev->dev, "authorized to connect\n");
+error_configure:
+error_device_descriptor:
+error_autoresume:
+out_authorized:
+	usb_unlock_device(usb_dev);	// complements locktree
+	return result;
+}
+
+
 static int hub_port_status(struct usb_hub *hub, int port1,
 			       u16 *status, u16 *change)
 {