usb: setup authorized_default attributes using usb_bus_notify

Currently, the authorized_default and interface_authorized_default
attributes for HCD are set up after the uevent has been sent to userland.
This creates a race condition where userland may fail to access this
file when processing the event. Move the appending of these attributes
earlier relying on the usb_bus_notify dispatcher.

Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190806110050.38918-1-tweek@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 9320787ac2e648cb7a8c319b8b56f2e95623ff9b..2ccbc2f83570141c7dc6c3b3bfe882ca5286eac3 100644 (file)
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -103,11 +103,6 @@ static DEFINE_SPINLOCK(hcd_urb_unlink_lock);
 /* wait queue for synchronous unlinks */
 DECLARE_WAIT_QUEUE_HEAD(usb_kill_urb_queue);
 
-static inline int is_root_hub(struct usb_device *udev)
-{
-       return (udev->parent == NULL);
-}
-
 /*-------------------------------------------------------------------------*/
 
 /*
@@ -880,101 +875,6 @@ static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 }
 
 
-
-/*
- * Show & store the current value of authorized_default
- */
-static ssize_t authorized_default_show(struct device *dev,
-                                      struct device_attribute *attr, char *buf)
-{
-       struct usb_device *rh_usb_dev = to_usb_device(dev);
-       struct usb_bus *usb_bus = rh_usb_dev->bus;
-       struct usb_hcd *hcd;
-
-       hcd = bus_to_hcd(usb_bus);
-       return snprintf(buf, PAGE_SIZE, "%u\n", hcd->dev_policy);
-}
-
-static ssize_t authorized_default_store(struct device *dev,
-                                       struct device_attribute *attr,
-                                       const char *buf, size_t size)
-{
-       ssize_t result;
-       unsigned val;
-       struct usb_device *rh_usb_dev = to_usb_device(dev);
-       struct usb_bus *usb_bus = rh_usb_dev->bus;
-       struct usb_hcd *hcd;
-
-       hcd = bus_to_hcd(usb_bus);
-       result = sscanf(buf, "%u\n", &val);
-       if (result == 1) {
-               hcd->dev_policy = val <= USB_DEVICE_AUTHORIZE_INTERNAL ?
-                       val : USB_DEVICE_AUTHORIZE_ALL;
-               result = size;
-       } else {
-               result = -EINVAL;
-       }
-       return result;
-}
-static DEVICE_ATTR_RW(authorized_default);
-
-/*
- * interface_authorized_default_show - show default authorization status
- * for USB interfaces
- *
- * note: interface_authorized_default is the default value
- *       for initializing the authorized attribute of interfaces
- */
-static ssize_t interface_authorized_default_show(struct device *dev,
-               struct device_attribute *attr, char *buf)
-{
-       struct usb_device *usb_dev = to_usb_device(dev);
-       struct usb_hcd *hcd = bus_to_hcd(usb_dev->bus);
-
-       return sprintf(buf, "%u\n", !!HCD_INTF_AUTHORIZED(hcd));
-}
-
-/*
- * interface_authorized_default_store - store default authorization status
- * for USB interfaces
- *
- * note: interface_authorized_default is the default value
- *       for initializing the authorized attribute of interfaces
- */
-static ssize_t interface_authorized_default_store(struct device *dev,
-               struct device_attribute *attr, const char *buf, size_t count)
-{
-       struct usb_device *usb_dev = to_usb_device(dev);
-       struct usb_hcd *hcd = bus_to_hcd(usb_dev->bus);
-       int rc = count;
-       bool val;
-
-       if (strtobool(buf, &val) != 0)
-               return -EINVAL;
-
-       if (val)
-               set_bit(HCD_FLAG_INTF_AUTHORIZED, &hcd->flags);
-       else
-               clear_bit(HCD_FLAG_INTF_AUTHORIZED, &hcd->flags);
-
-       return rc;
-}
-static DEVICE_ATTR_RW(interface_authorized_default);
-
-/* Group all the USB bus attributes */
-static struct attribute *usb_bus_attrs[] = {
-               &dev_attr_authorized_default.attr,
-               &dev_attr_interface_authorized_default.attr,
-               NULL,
-};
-
-static const struct attribute_group usb_bus_attr_group = {
-       .name = NULL,   /* we want them in the same directory */
-       .attrs = usb_bus_attrs,
-};
-
-
-
 /*-------------------------------------------------------------------------*/
 
 /**
@@ -2894,32 +2794,11 @@ int usb_add_hcd(struct usb_hcd *hcd,
        if (retval != 0)
                goto err_register_root_hub;
 
-       retval = sysfs_create_group(&rhdev->dev.kobj, &usb_bus_attr_group);
-       if (retval < 0) {
-               printk(KERN_ERR "Cannot register USB bus sysfs attributes: %d\n",
-                      retval);
-               goto error_create_attr_group;
-       }
        if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
                usb_hcd_poll_rh_status(hcd);
 
        return retval;
 
-error_create_attr_group:
-       clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
-       if (HC_IS_RUNNING(hcd->state))
-               hcd->state = HC_STATE_QUIESCING;
-       spin_lock_irq(&hcd_root_hub_lock);
-       hcd->rh_registered = 0;
-       spin_unlock_irq(&hcd_root_hub_lock);
-
-#ifdef CONFIG_PM
-       cancel_work_sync(&hcd->wakeup_work);
-#endif
-       cancel_work_sync(&hcd->died_work);
-       mutex_lock(&usb_bus_idr_lock);
-       usb_disconnect(&rhdev);         /* Sets rhdev to NULL */
-       mutex_unlock(&usb_bus_idr_lock);
 err_register_root_hub:
        hcd->rh_pollable = 0;
        clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
@@ -2963,8 +2842,6 @@ void usb_remove_hcd(struct usb_hcd *hcd)
        dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);
 
        usb_get_dev(rhdev);
-       sysfs_remove_group(&rhdev->dev.kobj, &usb_bus_attr_group);
-
        clear_bit(HCD_FLAG_RH_RUNNING, &hcd->flags);
        if (HC_IS_RUNNING (hcd->state))
                hcd->state = HC_STATE_QUIESCING;

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 7e88fdfe3cf5c7c23ba7e9878904a8e72db7686c..f19694e69f5c3eda9f58ba317a81b43096d8228d 100644 (file)
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -15,6 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/usb.h>
+#include <linux/usb/hcd.h>
 #include <linux/usb/quirks.h>
 #include <linux/of.h>
 #include "usb.h"
@@ -922,6 +923,116 @@ static struct bin_attribute dev_bin_attr_descriptors = {
        .size = 18 + 65535,     /* dev descr + max-size raw descriptor */
 };
 
+/*
+ * Show & store the current value of authorized_default
+ */
+static ssize_t authorized_default_show(struct device *dev,
+                                      struct device_attribute *attr, char *buf)
+{
+       struct usb_device *rh_usb_dev = to_usb_device(dev);
+       struct usb_bus *usb_bus = rh_usb_dev->bus;
+       struct usb_hcd *hcd;
+
+       hcd = bus_to_hcd(usb_bus);
+       return snprintf(buf, PAGE_SIZE, "%u\n", hcd->dev_policy);
+}
+
+static ssize_t authorized_default_store(struct device *dev,
+                                       struct device_attribute *attr,
+                                       const char *buf, size_t size)
+{
+       ssize_t result;
+       unsigned int val;
+       struct usb_device *rh_usb_dev = to_usb_device(dev);
+       struct usb_bus *usb_bus = rh_usb_dev->bus;
+       struct usb_hcd *hcd;
+
+       hcd = bus_to_hcd(usb_bus);
+       result = sscanf(buf, "%u\n", &val);
+       if (result == 1) {
+               hcd->dev_policy = val <= USB_DEVICE_AUTHORIZE_INTERNAL ?
+                       val : USB_DEVICE_AUTHORIZE_ALL;
+               result = size;
+       } else {
+               result = -EINVAL;
+       }
+       return result;
+}
+static DEVICE_ATTR_RW(authorized_default);
+
+/*
+ * interface_authorized_default_show - show default authorization status
+ * for USB interfaces
+ *
+ * note: interface_authorized_default is the default value
+ *       for initializing the authorized attribute of interfaces
+ */
+static ssize_t interface_authorized_default_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct usb_device *usb_dev = to_usb_device(dev);
+       struct usb_hcd *hcd = bus_to_hcd(usb_dev->bus);
+
+       return sprintf(buf, "%u\n", !!HCD_INTF_AUTHORIZED(hcd));
+}
+
+/*
+ * interface_authorized_default_store - store default authorization status
+ * for USB interfaces
+ *
+ * note: interface_authorized_default is the default value
+ *       for initializing the authorized attribute of interfaces
+ */
+static ssize_t interface_authorized_default_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct usb_device *usb_dev = to_usb_device(dev);
+       struct usb_hcd *hcd = bus_to_hcd(usb_dev->bus);
+       int rc = count;
+       bool val;
+
+       if (strtobool(buf, &val) != 0)
+               return -EINVAL;
+
+       if (val)
+               set_bit(HCD_FLAG_INTF_AUTHORIZED, &hcd->flags);
+       else
+               clear_bit(HCD_FLAG_INTF_AUTHORIZED, &hcd->flags);
+
+       return rc;
+}
+static DEVICE_ATTR_RW(interface_authorized_default);
+
+/* Group all the USB bus attributes */
+static struct attribute *usb_bus_attrs[] = {
+               &dev_attr_authorized_default.attr,
+               &dev_attr_interface_authorized_default.attr,
+               NULL,
+};
+
+static const struct attribute_group usb_bus_attr_group = {
+       .name = NULL,   /* we want them in the same directory */
+       .attrs = usb_bus_attrs,
+};
+
+
+static int add_default_authorized_attributes(struct device *dev)
+{
+       int rc = 0;
+
+       if (is_usb_device(dev))
+               rc = sysfs_create_group(&dev->kobj, &usb_bus_attr_group);
+
+       return rc;
+}
+
+static void remove_default_authorized_attributes(struct device *dev)
+{
+       if (is_usb_device(dev)) {
+               sysfs_remove_group(&dev->kobj, &usb_bus_attr_group);
+       }
+}
+
 int usb_create_sysfs_dev_files(struct usb_device *udev)
 {
        struct device *dev = &udev->dev;
@@ -938,7 +1049,14 @@ int usb_create_sysfs_dev_files(struct usb_device *udev)
        retval = add_power_attributes(dev);
        if (retval)
                goto error;
+
+       if (is_root_hub(udev)) {
+               retval = add_default_authorized_attributes(dev);
+               if (retval)
+                       goto error;
+       }
        return retval;
+
 error:
        usb_remove_sysfs_dev_files(udev);
        return retval;
@@ -948,6 +1066,9 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev)
 {
        struct device *dev = &udev->dev;
 
+       if (is_root_hub(udev))
+               remove_default_authorized_attributes(dev);
+
        remove_power_attributes(dev);
        remove_persist_attributes(dev);
        device_remove_bin_file(dev, &dev_bin_attr_descriptors);

diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index bd8d01f85a1371dffa8f32e522ecaa4ae5e8e23e..0c9fde5ad0524b50f1789803dbd00fa8adec4713 100644 (file)
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -153,6 +153,11 @@ static inline int is_usb_port(const struct device *dev)
        return dev->type == &usb_port_device_type;
 }
 
+static inline int is_root_hub(struct usb_device *udev)
+{
+       return (udev->parent == NULL);
+}
+
 /* Do the same for device drivers and interface drivers. */
 
 static inline int is_usb_device_driver(struct device_driver *drv)