usb: interface authorization: SysFS part of USB interface authorization

This introduces an attribute for each interface to
authorize (1) or deauthorize (0) it:
/sys/bus/usb/devices/INTERFACE/authorized

Signed-off-by: Stefan Koch <stefan.koch10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index cfc68c11c3f5..d9ec2de6c4cf 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -957,6 +957,41 @@ static ssize_t supports_autosuspend_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(supports_autosuspend);
 
+/*
+ * interface_authorized_show - show authorization status of an USB interface
+ * 1 is authorized, 0 is deauthorized
+ */
+static ssize_t interface_authorized_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+        struct usb_interface *intf = to_usb_interface(dev);
+
+        return sprintf(buf, "%u\n", intf->authorized);
+}
+
+/*
+ * interface_authorized_store - authorize or deauthorize an USB interface
+ */
+static ssize_t interface_authorized_store(struct device *dev,
+                struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct usb_interface *intf = to_usb_interface(dev);
+        bool val;
+
+        if (strtobool(buf, &val) != 0)
+                return -EINVAL;
+
+        if (val)
+                usb_authorize_interface(intf);
+        else
+                usb_deauthorize_interface(intf);
+
+        return count;
+}
+static struct device_attribute dev_attr_interface_authorized =
+                __ATTR(authorized, S_IRUGO | S_IWUSR,
+                interface_authorized_show, interface_authorized_store);
+
 static struct attribute *intf_attrs[] = {
         &dev_attr_bInterfaceNumber.attr,
         &dev_attr_bAlternateSetting.attr,
@@ -966,6 +1001,7 @@ static struct attribute *intf_attrs[] = {
         &dev_attr_bInterfaceProtocol.attr,
         &dev_attr_modalias.attr,
         &dev_attr_supports_autosuspend.attr,
+        &dev_attr_interface_authorized.attr,
         NULL,
 };
 static struct attribute_group intf_attr_grp = {