usb: hook up device authorization to sysfs

Makes it possible to control the authorization of USB devices through
sysfs's /sys/usb/devices/*/authorize.

Update: per Adrian Bunk's suggestion, make dev_attr_authorized_default static

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

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 2ab222be8fd1..e02590297d31 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -413,6 +413,44 @@ usb_descriptor_attr(bDeviceProtocol, "%02x\n")
 usb_descriptor_attr(bNumConfigurations, "%d\n")
 usb_descriptor_attr(bMaxPacketSize0, "%d\n")
 
+
+
+/* show if the device is authorized (1) or not (0) */
+static ssize_t usb_dev_authorized_show(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf)
+{
+        struct usb_device *usb_dev = to_usb_device(dev);
+        return snprintf(buf, PAGE_SIZE, "%u\n", usb_dev->authorized);
+}
+
+
+/*
+ * Authorize a device to be used in the system
+ *
+ * Writing a 0 deauthorizes the device, writing a 1 authorizes it.
+ */
+static ssize_t usb_dev_authorized_store(struct device *dev,
+                                        struct device_attribute *attr,
+                                        const char *buf, size_t size)
+{
+        ssize_t result;
+        struct usb_device *usb_dev = to_usb_device(dev);
+        unsigned val;
+        result = sscanf(buf, "%u\n", &val);
+        if (result != 1)
+                result = -EINVAL;
+        else if (val == 0)
+                result = usb_deauthorize_device(usb_dev);
+        else
+                result = usb_authorize_device(usb_dev);
+        return result < 0? result : size;
+}
+
+static DEVICE_ATTR(authorized, 0644,
+            usb_dev_authorized_show, usb_dev_authorized_store);
+
+
 static struct attribute *dev_attrs[] = {
         /* current configuration's attributes */
         &dev_attr_configuration.attr,
@@ -435,6 +473,7 @@ static struct attribute *dev_attrs[] = {
         &dev_attr_version.attr,
         &dev_attr_maxchild.attr,
         &dev_attr_quirks.attr,
+        &dev_attr_authorized.attr,
         NULL,
 };
 static struct attribute_group dev_attr_grp = {