[PATCH] sanitize __user_walk_fd() et.al.

* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
user_path_at(dfd, pathname, flags, &path)
user_path(pathname, &path)
user_lpath(pathname, &path)
user_path_dir(pathname, &path) (fail if not a directory)
The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.

Signed-off-by: Al Viro <[e-mail]>

arch/alpha/kernel/osf_sys.c

···
 }
 
 asmlinkage int
-osf_statfs(char __user *path, struct osf_statfs __user *buffer, unsigned long bufsiz)
+osf_statfs(char __user *pathname, struct osf_statfs __user *buffer, unsigned long bufsiz)
 {
-	struct nameidata nd;
+	struct path path;
 	int retval;
 
-	retval = user_path_walk(path, &nd);
+	retval = user_path(pathname, &path);
 	if (!retval) {
-		retval = do_osf_statfs(nd.path.dentry, buffer, bufsiz);
-		path_put(&nd.path);
+		retval = do_osf_statfs(path.dentry, buffer, bufsiz);
+		path_put(&path);
 	}
 	return retval;
 }

arch/parisc/hpux/sys_hpux.c

···
 }
 
 /* hpux statfs */
-asmlinkage long hpux_statfs(const char __user *path,
+asmlinkage long hpux_statfs(const char __user *pathname,
 						struct hpux_statfs __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct hpux_statfs tmp;
-		error = vfs_statfs_hpux(nd.path.dentry, &tmp);
+		error = vfs_statfs_hpux(path.dentry, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }

fs/coda/pioctl.c

···
 static int coda_pioctl(struct inode * inode, struct file * filp, 
                        unsigned int cmd, unsigned long user_data)
 {
-	struct nameidata nd;
+	struct path path;
         int error;
 	struct PioctlData data;
         struct inode *target_inode = NULL;
···
          * Look up the pathname. Note that the pathname is in 
          * user memory, and namei takes care of this
          */
-        if ( data.follow ) {
-                error = user_path_walk(data.path, &nd);
+        if (data.follow) {
+                error = user_path(data.path, &path);
 	} else {
-	        error = user_path_walk_link(data.path, &nd);
+	        error = user_lpath(data.path, &path);
 	}
 		
 	if ( error ) {
 		return error;
         } else {
-		target_inode = nd.path.dentry->d_inode;
+		target_inode = path.dentry->d_inode;
 	}
 	
 	/* return if it is not a Coda inode */
 	if ( target_inode->i_sb != inode->i_sb ) {
-		path_put(&nd.path);
+		path_put(&path);
 	        return  -EINVAL;
 	}
 
···
 
 	error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
 
-	path_put(&nd.path);
+	path_put(&path);
         return error;
 }
 

fs/compat.c

···
  * The following statfs calls are copies of code from fs/open.c and
  * should be checked against those from time to time
  */
-asmlinkage long compat_sys_statfs(const char __user *path, struct compat_statfs __user *buf)
+asmlinkage long compat_sys_statfs(const char __user *pathname, struct compat_statfs __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(nd.path.dentry, &tmp);
+		error = vfs_statfs(path.dentry, &tmp);
 		if (!error)
 			error = put_compat_statfs(buf, &tmp);
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }
···
 	return 0;
 }
 
-asmlinkage long compat_sys_statfs64(const char __user *path, compat_size_t sz, struct compat_statfs64 __user *buf)
+asmlinkage long compat_sys_statfs64(const char __user *pathname, compat_size_t sz, struct compat_statfs64 __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
 	if (sz != sizeof(*buf))
 		return -EINVAL;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(nd.path.dentry, &tmp);
+		error = vfs_statfs(path.dentry, &tmp);
 		if (!error)
 			error = put_compat_statfs64(buf, &tmp);
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }

fs/inotify_user.c

···
 }
 
 /*
- * find_inode - resolve a user-given path to a specific inode and return a nd
+ * find_inode - resolve a user-given path to a specific inode
  */
-static int find_inode(const char __user *dirname, struct nameidata *nd,
+static int find_inode(const char __user *dirname, struct path *path,
 		      unsigned flags)
 {
 	int error;
 
-	error = __user_walk(dirname, flags, nd);
+	error = user_path_at(AT_FDCWD, dirname, flags, path);
 	if (error)
 		return error;
 	/* you can only watch an inode if you have read permissions on it */
-	error = inode_permission(nd->path.dentry->d_inode, MAY_READ);
+	error = inode_permission(path->dentry->d_inode, MAY_READ);
 	if (error)
-		path_put(&nd->path);
+		path_put(path);
 	return error;
 }
 
···
 	return sys_inotify_init1(0);
 }
 
-asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
+asmlinkage long sys_inotify_add_watch(int fd, const char __user *pathname, u32 mask)
 {
 	struct inode *inode;
 	struct inotify_device *dev;
-	struct nameidata nd;
+	struct path path;
 	struct file *filp;
 	int ret, fput_needed;
 	unsigned flags = 0;
···
 	if (mask & IN_ONLYDIR)
 		flags |= LOOKUP_DIRECTORY;
 
-	ret = find_inode(path, &nd, flags);
+	ret = find_inode(pathname, &path, flags);
 	if (unlikely(ret))
 		goto fput_and_out;
 
-	/* inode held in place by reference to nd; dev by fget on fd */
-	inode = nd.path.dentry->d_inode;
+	/* inode held in place by reference to path; dev by fget on fd */
+	inode = path.dentry->d_inode;
 	dev = filp->private_data;
 
 	mutex_lock(&dev->up_mutex);
···
 		ret = create_watch(dev, inode, mask);
 	mutex_unlock(&dev->up_mutex);
 
-	path_put(&nd.path);
+	path_put(&path);
 fput_and_out:
 	fput_light(filp, fput_needed);
 	return ret;

fs/namei.c

···
 	return __lookup_hash(&this, base, NULL);
 }
 
-int __user_walk_fd(int dfd, const char __user *name, unsigned flags,
-			    struct nameidata *nd)
+int user_path_at(int dfd, const char __user *name, unsigned flags,
+		 struct path *path)
 {
+	struct nameidata nd;
 	char *tmp = getname(name);
 	int err = PTR_ERR(tmp);
-
 	if (!IS_ERR(tmp)) {
-		err = do_path_lookup(dfd, tmp, flags, nd);
+
+		BUG_ON(flags & LOOKUP_PARENT);
+
+		err = do_path_lookup(dfd, tmp, flags, &nd);
 		putname(tmp);
+		if (!err)
+			*path = nd.path;
 	}
 	return err;
-}
-
-int __user_walk(const char __user *name, unsigned flags, struct nameidata *nd)
-{
-	return __user_walk_fd(AT_FDCWD, name, flags, nd);
 }
 
 /*
···
 			   int flags)
 {
 	struct dentry *new_dentry;
-	struct nameidata nd, old_nd;
+	struct nameidata nd;
+	struct path old_path;
 	int error;
 	char * to;
 
···
 	if (IS_ERR(to))
 		return PTR_ERR(to);
 
-	error = __user_walk_fd(olddfd, oldname,
-			       flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
-			       &old_nd);
+	error = user_path_at(olddfd, oldname,
+			     flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
+			     &old_path);
 	if (error)
 		goto exit;
 	error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
 	if (error)
 		goto out;
 	error = -EXDEV;
-	if (old_nd.path.mnt != nd.path.mnt)
+	if (old_path.mnt != nd.path.mnt)
 		goto out_release;
 	new_dentry = lookup_create(&nd, 0);
 	error = PTR_ERR(new_dentry);
···
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_dput;
-	error = vfs_link(old_nd.path.dentry, nd.path.dentry->d_inode, new_dentry);
+	error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
 	mnt_drop_write(nd.path.mnt);
 out_dput:
 	dput(new_dentry);
···
 out_release:
 	path_put(&nd.path);
 out:
-	path_put(&old_nd.path);
+	path_put(&old_path);
 exit:
 	putname(to);
 
···
 	.put_link	= page_put_link,
 };
 
-EXPORT_SYMBOL(__user_walk);
-EXPORT_SYMBOL(__user_walk_fd);
+EXPORT_SYMBOL(user_path_at);
 EXPORT_SYMBOL(follow_down);
 EXPORT_SYMBOL(follow_up);
 EXPORT_SYMBOL(get_write_access); /* binfmt_aout */

fs/namespace.c

···
 
 asmlinkage long sys_umount(char __user * name, int flags)
 {
-	struct nameidata nd;
+	struct path path;
 	int retval;
 
-	retval = __user_walk(name, LOOKUP_FOLLOW, &nd);
+	retval = user_path(name, &path);
 	if (retval)
 		goto out;
 	retval = -EINVAL;
-	if (nd.path.dentry != nd.path.mnt->mnt_root)
+	if (path.dentry != path.mnt->mnt_root)
 		goto dput_and_out;
-	if (!check_mnt(nd.path.mnt))
+	if (!check_mnt(path.mnt))
 		goto dput_and_out;
 
 	retval = -EPERM;
 	if (!capable(CAP_SYS_ADMIN))
 		goto dput_and_out;
 
-	retval = do_umount(nd.path.mnt, flags);
+	retval = do_umount(path.mnt, flags);
 dput_and_out:
 	/* we mustn't call path_put() as that would clear mnt_expiry_mark */
-	dput(nd.path.dentry);
-	mntput_no_expire(nd.path.mnt);
+	dput(path.dentry);
+	mntput_no_expire(path.mnt);
 out:
 	return retval;
 }
···
 			       const char __user * put_old)
 {
 	struct vfsmount *tmp;
-	struct nameidata new_nd, old_nd;
-	struct path parent_path, root_parent, root;
+	struct path new, old, parent_path, root_parent, root;
 	int error;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
-			    &new_nd);
+	error = user_path_dir(new_root, &new);
 	if (error)
 		goto out0;
 	error = -EINVAL;
-	if (!check_mnt(new_nd.path.mnt))
+	if (!check_mnt(new.mnt))
 		goto out1;
 
-	error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd);
+	error = user_path_dir(put_old, &old);
 	if (error)
 		goto out1;
 
-	error = security_sb_pivotroot(&old_nd.path, &new_nd.path);
+	error = security_sb_pivotroot(&old, &new);
 	if (error) {
-		path_put(&old_nd.path);
+		path_put(&old);
 		goto out1;
 	}
 
···
 	path_get(&current->fs->root);
 	read_unlock(&current->fs->lock);
 	down_write(&namespace_sem);
-	mutex_lock(&old_nd.path.dentry->d_inode->i_mutex);
+	mutex_lock(&old.dentry->d_inode->i_mutex);
 	error = -EINVAL;
-	if (IS_MNT_SHARED(old_nd.path.mnt) ||
-		IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) ||
+	if (IS_MNT_SHARED(old.mnt) ||
+		IS_MNT_SHARED(new.mnt->mnt_parent) ||
 		IS_MNT_SHARED(root.mnt->mnt_parent))
 		goto out2;
 	if (!check_mnt(root.mnt))
 		goto out2;
 	error = -ENOENT;
-	if (IS_DEADDIR(new_nd.path.dentry->d_inode))
+	if (IS_DEADDIR(new.dentry->d_inode))
 		goto out2;
-	if (d_unhashed(new_nd.path.dentry) && !IS_ROOT(new_nd.path.dentry))
+	if (d_unhashed(new.dentry) && !IS_ROOT(new.dentry))
 		goto out2;
-	if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
+	if (d_unhashed(old.dentry) && !IS_ROOT(old.dentry))
 		goto out2;
 	error = -EBUSY;
-	if (new_nd.path.mnt == root.mnt ||
-	    old_nd.path.mnt == root.mnt)
+	if (new.mnt == root.mnt ||
+	    old.mnt == root.mnt)
 		goto out2; /* loop, on the same file system  */
 	error = -EINVAL;
 	if (root.mnt->mnt_root != root.dentry)
 		goto out2; /* not a mountpoint */
 	if (root.mnt->mnt_parent == root.mnt)
 		goto out2; /* not attached */
-	if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
+	if (new.mnt->mnt_root != new.dentry)
 		goto out2; /* not a mountpoint */
-	if (new_nd.path.mnt->mnt_parent == new_nd.path.mnt)
+	if (new.mnt->mnt_parent == new.mnt)
 		goto out2; /* not attached */
 	/* make sure we can reach put_old from new_root */
-	tmp = old_nd.path.mnt;
+	tmp = old.mnt;
 	spin_lock(&vfsmount_lock);
-	if (tmp != new_nd.path.mnt) {
+	if (tmp != new.mnt) {
 		for (;;) {
 			if (tmp->mnt_parent == tmp)
 				goto out3; /* already mounted on put_old */
-			if (tmp->mnt_parent == new_nd.path.mnt)
+			if (tmp->mnt_parent == new.mnt)
 				break;
 			tmp = tmp->mnt_parent;
 		}
-		if (!is_subdir(tmp->mnt_mountpoint, new_nd.path.dentry))
+		if (!is_subdir(tmp->mnt_mountpoint, new.dentry))
 			goto out3;
-	} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
+	} else if (!is_subdir(old.dentry, new.dentry))
 		goto out3;
-	detach_mnt(new_nd.path.mnt, &parent_path);
+	detach_mnt(new.mnt, &parent_path);
 	detach_mnt(root.mnt, &root_parent);
 	/* mount old root on put_old */
-	attach_mnt(root.mnt, &old_nd.path);
+	attach_mnt(root.mnt, &old);
 	/* mount new_root on / */
-	attach_mnt(new_nd.path.mnt, &root_parent);
+	attach_mnt(new.mnt, &root_parent);
 	touch_mnt_namespace(current->nsproxy->mnt_ns);
 	spin_unlock(&vfsmount_lock);
-	chroot_fs_refs(&root, &new_nd.path);
-	security_sb_post_pivotroot(&root, &new_nd.path);
+	chroot_fs_refs(&root, &new);
+	security_sb_post_pivotroot(&root, &new);
 	error = 0;
 	path_put(&root_parent);
 	path_put(&parent_path);
 out2:
-	mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
+	mutex_unlock(&old.dentry->d_inode->i_mutex);
 	up_write(&namespace_sem);
 	path_put(&root);
-	path_put(&old_nd.path);
+	path_put(&old);
 out1:
-	path_put(&new_nd.path);
+	path_put(&new);
 out0:
 	return error;
 out3:

fs/open.c

···
 	return 0;
 }
 
-asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf)
+asmlinkage long sys_statfs(const char __user *pathname, struct statfs __user * buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct statfs tmp;
-		error = vfs_statfs_native(nd.path.dentry, &tmp);
+		error = vfs_statfs_native(path.dentry, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }
 
 
-asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf)
+asmlinkage long sys_statfs64(const char __user *pathname, size_t sz, struct statfs64 __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	long error;
 
 	if (sz != sizeof(*buf))
 		return -EINVAL;
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct statfs64 tmp;
-		error = vfs_statfs64(nd.path.dentry, &tmp);
+		error = vfs_statfs64(path.dentry, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }
···
 	return err;
 }
 
-static long do_sys_truncate(const char __user * path, loff_t length)
+static long do_sys_truncate(const char __user *pathname, loff_t length)
 {
-	struct nameidata nd;
-	struct inode * inode;
+	struct path path;
+	struct inode *inode;
 	int error;
 
 	error = -EINVAL;
 	if (length < 0)	/* sorry, but loff_t says... */
 		goto out;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (error)
 		goto out;
-	inode = nd.path.dentry->d_inode;
+	inode = path.dentry->d_inode;
 
 	/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
 	error = -EISDIR;
···
 	if (!S_ISREG(inode->i_mode))
 		goto dput_and_out;
 
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (error)
 		goto dput_and_out;
 
···
 	error = locks_verify_truncate(inode, NULL, length);
 	if (!error) {
 		DQUOT_INIT(inode);
-		error = do_truncate(nd.path.dentry, length, 0, NULL);
+		error = do_truncate(path.dentry, length, 0, NULL);
 	}
 
 put_write_and_out:
 	put_write_access(inode);
 mnt_drop_write_and_out:
-	mnt_drop_write(nd.path.mnt);
+	mnt_drop_write(path.mnt);
 dput_and_out:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
···
  */
 asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 {
-	struct nameidata nd;
+	struct path path;
 	struct inode *inode;
 	int old_fsuid, old_fsgid;
 	kernel_cap_t uninitialized_var(old_cap);  /* !SECURE_NO_SETUID_FIXUP */
···
 		 * FIXME: There is a race here against sys_capset.  The
 		 * capabilities can change yet we will restore the old
 		 * value below.  We should hold task_capabilities_lock,
-		 * but we cannot because user_path_walk can sleep.
+		 * but we cannot because user_path_at can sleep.
 		 */
 #endif /* ndef CONFIG_SECURITY_FILE_CAPABILITIES */
 		if (current->uid)
···
 			old_cap = cap_set_effective(current->cap_permitted);
 	}
 
-	res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
+	res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
 	if (res)
 		goto out;
 
-	inode = nd.path.dentry->d_inode;
+	inode = path.dentry->d_inode;
 
 	if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
 		/*
···
 		 * with the "noexec" flag.
 		 */
 		res = -EACCES;
-		if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
+		if (path.mnt->mnt_flags & MNT_NOEXEC)
 			goto out_path_release;
 	}
 
···
 	 * inherently racy and know that the fs may change
 	 * state before we even see this result.
 	 */
-	if (__mnt_is_readonly(nd.path.mnt))
+	if (__mnt_is_readonly(path.mnt))
 		res = -EROFS;
 
 out_path_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	current->fsuid = old_fsuid;
 	current->fsgid = old_fsgid;
···
 
 asmlinkage long sys_chdir(const char __user * filename)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
+	error = user_path_dir(filename, &path);
 	if (error)
 		goto out;
 
-	error = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
+	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
 	if (error)
 		goto dput_and_out;
 
-	set_fs_pwd(current->fs, &nd.path);
+	set_fs_pwd(current->fs, &path);
 
 dput_and_out:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
···
 
 asmlinkage long sys_chroot(const char __user * filename)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
+	error = user_path_dir(filename, &path);
 	if (error)
 		goto out;
 
-	error = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
+	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
 	if (error)
 		goto dput_and_out;
 
···
 	if (!capable(CAP_SYS_CHROOT))
 		goto dput_and_out;
 
-	set_fs_root(current->fs, &nd.path);
+	set_fs_root(current->fs, &path);
 	error = 0;
 dput_and_out:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
···
 asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
 			     mode_t mode)
 {
-	struct nameidata nd;
-	struct inode * inode;
+	struct path path;
+	struct inode *inode;
 	int error;
 	struct iattr newattrs;
 
-	error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
+	error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
 	if (error)
 		goto out;
-	inode = nd.path.dentry->d_inode;
+	inode = path.dentry->d_inode;
 
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (error)
 		goto dput_and_out;
 	mutex_lock(&inode->i_mutex);
···
 		mode = inode->i_mode;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	error = notify_change(nd.path.dentry, &newattrs);
+	error = notify_change(path.dentry, &newattrs);
 	mutex_unlock(&inode->i_mutex);
-	mnt_drop_write(nd.path.mnt);
+	mnt_drop_write(path.mnt);
 dput_and_out:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
···
 
 asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(filename, &nd);
+	error = user_path(filename, &path);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
+	error = chown_common(path.dentry, user, group);
+	mnt_drop_write(path.mnt);
 out_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
···
 asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
 			     gid_t group, int flag)
 {
-	struct nameidata nd;
+	struct path path;
 	int error = -EINVAL;
 	int follow;
 
···
 		goto out;
 
 	follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
-	error = __user_walk_fd(dfd, filename, follow, &nd);
+	error = user_path_at(dfd, filename, follow, &path);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
+	error = chown_common(path.dentry, user, group);
+	mnt_drop_write(path.mnt);
 out_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }
 
 asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk_link(filename, &nd);
+	error = user_lpath(filename, &path);
 	if (error)
 		goto out;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (error)
 		goto out_release;
-	error = chown_common(nd.path.dentry, user, group);
-	mnt_drop_write(nd.path.mnt);
+	error = chown_common(path.dentry, user, group);
+	mnt_drop_write(path.mnt);
 out_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return error;
 }

fs/stat.c

···
 
 int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd);
+	error = user_path_at(dfd, name, LOOKUP_FOLLOW, &path);
 	if (!error) {
-		error = vfs_getattr(nd.path.mnt, nd.path.dentry, stat);
-		path_put(&nd.path);
+		error = vfs_getattr(path.mnt, path.dentry, stat);
+		path_put(&path);
 	}
 	return error;
 }
···
 
 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = __user_walk_fd(dfd, name, 0, &nd);
+	error = user_path_at(dfd, name, 0, &path);
 	if (!error) {
-		error = vfs_getattr(nd.path.mnt, nd.path.dentry, stat);
-		path_put(&nd.path);
+		error = vfs_getattr(path.mnt, path.dentry, stat);
+		path_put(&path);
 	}
 	return error;
 }
···
 	return error;
 }
 
-asmlinkage long sys_readlinkat(int dfd, const char __user *path,
+asmlinkage long sys_readlinkat(int dfd, const char __user *pathname,
 				char __user *buf, int bufsiz)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
 	if (bufsiz <= 0)
 		return -EINVAL;
 
-	error = __user_walk_fd(dfd, path, 0, &nd);
+	error = user_path_at(dfd, pathname, 0, &path);
 	if (!error) {
-		struct inode *inode = nd.path.dentry->d_inode;
+		struct inode *inode = path.dentry->d_inode;
 
 		error = -EINVAL;
 		if (inode->i_op && inode->i_op->readlink) {
-			error = security_inode_readlink(nd.path.dentry);
+			error = security_inode_readlink(path.dentry);
 			if (!error) {
-				touch_atime(nd.path.mnt, nd.path.dentry);
-				error = inode->i_op->readlink(nd.path.dentry,
+				touch_atime(path.mnt, path.dentry);
+				error = inode->i_op->readlink(path.dentry,
 							      buf, bufsiz);
 			}
 		}
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }

fs/utimes.c

···
 		error = utimes_common(&file->f_path, times);
 		fput(file);
 	} else {
-		struct nameidata nd;
+		struct path path;
 		int lookup_flags = 0;
 
 		if (!(flags & AT_SYMLINK_NOFOLLOW))
 			lookup_flags |= LOOKUP_FOLLOW;
 
-		error = __user_walk_fd(dfd, filename, lookup_flags, &nd);
+		error = user_path_at(dfd, filename, lookup_flags, &path);
 		if (error)
 			goto out;
 
-		error = utimes_common(&nd.path, times);
-		path_put(&nd.path);
+		error = utimes_common(&path, times);
+		path_put(&path);
 	}
 
 out:

fs/xattr.c

···
 }
 
 asmlinkage long
-sys_setxattr(const char __user *path, const char __user *name,
+sys_setxattr(const char __user *pathname, const char __user *name,
 	     const void __user *value, size_t size, int flags)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (!error) {
-		error = setxattr(nd.path.dentry, name, value, size, flags);
-		mnt_drop_write(nd.path.mnt);
+		error = setxattr(path.dentry, name, value, size, flags);
+		mnt_drop_write(path.mnt);
 	}
-	path_put(&nd.path);
+	path_put(&path);
 	return error;
 }
 
 asmlinkage long
-sys_lsetxattr(const char __user *path, const char __user *name,
+sys_lsetxattr(const char __user *pathname, const char __user *name,
 	      const void __user *value, size_t size, int flags)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk_link(path, &nd);
+	error = user_lpath(pathname, &path);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (!error) {
-		error = setxattr(nd.path.dentry, name, value, size, flags);
-		mnt_drop_write(nd.path.mnt);
+		error = setxattr(path.dentry, name, value, size, flags);
+		mnt_drop_write(path.mnt);
 	}
-	path_put(&nd.path);
+	path_put(&path);
 	return error;
 }
 
···
 }
 
 asmlinkage ssize_t
-sys_getxattr(const char __user *path, const char __user *name,
+sys_getxattr(const char __user *pathname, const char __user *name,
 	     void __user *value, size_t size)
 {
-	struct nameidata nd;
+	struct path path;
 	ssize_t error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (error)
 		return error;
-	error = getxattr(nd.path.dentry, name, value, size);
-	path_put(&nd.path);
+	error = getxattr(path.dentry, name, value, size);
+	path_put(&path);
 	return error;
 }
 
 asmlinkage ssize_t
-sys_lgetxattr(const char __user *path, const char __user *name, void __user *value,
+sys_lgetxattr(const char __user *pathname, const char __user *name, void __user *value,
 	      size_t size)
 {
-	struct nameidata nd;
+	struct path path;
 	ssize_t error;
 
-	error = user_path_walk_link(path, &nd);
+	error = user_lpath(pathname, &path);
 	if (error)
 		return error;
-	error = getxattr(nd.path.dentry, name, value, size);
-	path_put(&nd.path);
+	error = getxattr(path.dentry, name, value, size);
+	path_put(&path);
 	return error;
 }
 
···
 }
 
 asmlinkage ssize_t
-sys_listxattr(const char __user *path, char __user *list, size_t size)
+sys_listxattr(const char __user *pathname, char __user *list, size_t size)
 {
-	struct nameidata nd;
+	struct path path;
 	ssize_t error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (error)
 		return error;
-	error = listxattr(nd.path.dentry, list, size);
-	path_put(&nd.path);
+	error = listxattr(path.dentry, list, size);
+	path_put(&path);
 	return error;
 }
 
 asmlinkage ssize_t
-sys_llistxattr(const char __user *path, char __user *list, size_t size)
+sys_llistxattr(const char __user *pathname, char __user *list, size_t size)
 {
-	struct nameidata nd;
+	struct path path;
 	ssize_t error;
 
-	error = user_path_walk_link(path, &nd);
+	error = user_lpath(pathname, &path);
 	if (error)
 		return error;
-	error = listxattr(nd.path.dentry, list, size);
-	path_put(&nd.path);
+	error = listxattr(path.dentry, list, size);
+	path_put(&path);
 	return error;
 }
 
···
 }
 
 asmlinkage long
-sys_removexattr(const char __user *path, const char __user *name)
+sys_removexattr(const char __user *pathname, const char __user *name)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (!error) {
-		error = removexattr(nd.path.dentry, name);
-		mnt_drop_write(nd.path.mnt);
+		error = removexattr(path.dentry, name);
+		mnt_drop_write(path.mnt);
 	}
-	path_put(&nd.path);
+	path_put(&path);
 	return error;
 }
 
 asmlinkage long
-sys_lremovexattr(const char __user *path, const char __user *name)
+sys_lremovexattr(const char __user *pathname, const char __user *name)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk_link(path, &nd);
+	error = user_lpath(pathname, &path);
 	if (error)
 		return error;
-	error = mnt_want_write(nd.path.mnt);
+	error = mnt_want_write(path.mnt);
 	if (!error) {
-		error = removexattr(nd.path.dentry, name);
-		mnt_drop_write(nd.path.mnt);
+		error = removexattr(path.dentry, name);
+		mnt_drop_write(path.mnt);
 	}
-	path_put(&nd.path);
+	path_put(&path);
 	return error;
 }
 

fs/xfs/linux-2.6/xfs_ioctl.c

···
 	switch (cmd) {
 	case XFS_IOC_PATH_TO_FSHANDLE:
 	case XFS_IOC_PATH_TO_HANDLE: {
-		struct nameidata	nd;
-		int			error;
-
-		error = user_path_walk_link((const char __user *)hreq.path, &nd);
+		struct path path;
+		int error = user_lpath((const char __user *)hreq.path, &path);
 		if (error)
 			return error;
 
-		ASSERT(nd.path.dentry);
-		ASSERT(nd.path.dentry->d_inode);
-		inode = igrab(nd.path.dentry->d_inode);
-		path_put(&nd.path);
+		ASSERT(path.dentry);
+		ASSERT(path.dentry->d_inode);
+		inode = igrab(path.dentry->d_inode);
+		path_put(&path);
 		break;
 	}
 

include/linux/namei.h

···
 #define LOOKUP_OPEN		(0x0100)
 #define LOOKUP_CREATE		(0x0200)
 
-extern int __user_walk(const char __user *, unsigned, struct nameidata *);
-extern int __user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *);
-#define user_path_walk(name,nd) \
-	__user_walk_fd(AT_FDCWD, name, LOOKUP_FOLLOW, nd)
-#define user_path_walk_link(name,nd) \
-	__user_walk_fd(AT_FDCWD, name, 0, nd)
+extern int user_path_at(int, const char __user *, unsigned, struct path *);
+
+#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
+#define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
+#define user_path_dir(name, path) \
+	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
+
 extern int path_lookup(const char *, unsigned, struct nameidata *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct nameidata *);