driver core: handle user namespaces properly with the uid/gid devtmpfs change

Now that devtmpfs is caring about uid/gid, we need to use the correct
internal types so users who have USER_NS enabled will have things work
properly for them.

Thanks to Eric for pointing this out, and the patch review.

Reported-by: Eric W. Biederman <[e-mail]>
Cc: Kay Sievers <[e-mail]>
Cc: Ming Lei <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

block/genhd.c

···
 };
 
 static char *block_devnode(struct device *dev, umode_t *mode,
-			   uid_t *uid, gid_t *gid)
+			   kuid_t *uid, kgid_t *gid)
 {
 	struct gendisk *disk = dev_to_disk(dev);
 

drivers/base/core.c

···
 		const char *tmp;
 		const char *name;
 		umode_t mode = 0;
-		uid_t uid = 0;
-		gid_t gid = 0;
+		kuid_t uid = GLOBAL_ROOT_UID;
+		kgid_t gid = GLOBAL_ROOT_GID;
 
 		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
 		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
···
 			add_uevent_var(env, "DEVNAME=%s", name);
 			if (mode)
 				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
-			if (uid)
-				add_uevent_var(env, "DEVUID=%u", uid);
-			if (gid)
-				add_uevent_var(env, "DEVGID=%u", gid);
+			if (!uid_eq(uid, GLOBAL_ROOT_UID))
+				add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
+			if (!gid_eq(gid, GLOBAL_ROOT_GID))
+				add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
 			kfree(tmp);
 		}
 	}
···
  * freed by the caller.
  */
 const char *device_get_devnode(struct device *dev,
-			       umode_t *mode, uid_t *uid, gid_t *gid,
+			       umode_t *mode, kuid_t *uid, kgid_t *gid,
 			       const char **tmp)
 {
 	char *s;

drivers/base/devtmpfs.c

···
 	int err;
 	const char *name;
 	umode_t mode;	/* 0 => delete */
-	uid_t uid;
-	gid_t gid;
+	kuid_t uid;
+	kgid_t gid;
 	struct device *dev;
 } *requests;
 
···
 		return 0;
 
 	req.mode = 0;
-	req.uid = 0;
-	req.gid = 0;
+	req.uid = GLOBAL_ROOT_UID;
+	req.gid = GLOBAL_ROOT_GID;
 	req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
 	if (!req.name)
 		return -ENOMEM;
···
 	return err;
 }
 
-static int handle_create(const char *nodename, umode_t mode, uid_t uid,
-			 gid_t gid, struct device *dev)
+static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
+			 kgid_t gid, struct device *dev)
 {
 	struct dentry *dentry;
 	struct path path;
···
 		struct iattr newattrs;
 
 		newattrs.ia_mode = mode;
-		newattrs.ia_uid = KUIDT_INIT(uid);
-		newattrs.ia_gid = KGIDT_INIT(gid);
+		newattrs.ia_uid = uid;
+		newattrs.ia_gid = gid;
 		newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
 		mutex_lock(&dentry->d_inode->i_mutex);
 		notify_change(dentry, &newattrs);
···
 
 static DECLARE_COMPLETION(setup_done);
 
-static int handle(const char *name, umode_t mode, uid_t uid, gid_t gid,
+static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
 		  struct device *dev)
 {
 	if (mode)

drivers/usb/core/usb.c

···
 
 
 static char *usb_devnode(struct device *dev,
-			 umode_t *mode, uid_t *uid, gid_t *gid)
+			 umode_t *mode, kuid_t *uid, kgid_t *gid)
 {
 	struct usb_device *usb_dev;
 

include/linux/device.h

···
 	const struct attribute_group **groups;
 	int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
 	char *(*devnode)(struct device *dev, umode_t *mode,
-			 uid_t *uid, gid_t *gid);
+			 kuid_t *uid, kgid_t *gid);
 	void (*release)(struct device *dev);
 
 	const struct dev_pm_ops *pm;
···
 extern int device_move(struct device *dev, struct device *new_parent,
 		       enum dpm_order dpm_order);
 extern const char *device_get_devnode(struct device *dev,
-				      umode_t *mode, uid_t *uid, gid_t *gid,
+				      umode_t *mode, kuid_t *uid, kgid_t *gid,
 				      const char **tmp);
 extern void *dev_get_drvdata(const struct device *dev);
 extern int dev_set_drvdata(struct device *dev, void *data);