Merge tag 'fsnotify_for_v5.1-rc2' of git://git.kernel.org/pub/scm/lin…

…ux/kernel/git/jack/linux-fs

Pull fsnotify fixes from Jan Kara:
 "One inotify and one fanotify fix"

* tag 'fsnotify_for_v5.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify: Allow copying of file handle to userspace
  inotify: Fix fsnotify_mark refcount leak in inotify_update_existing_watch()

fs/notify/fanotify/fanotify_user.c

@@ -208,6 +208,7 @@ static int copy_fid_to_user(struct fanotify_event *event, char __user *buf)
 {
 	struct fanotify_event_info_fid info = { };
 	struct file_handle handle = { };
+	unsigned char bounce[FANOTIFY_INLINE_FH_LEN], *fh;
 	size_t fh_len = event->fh_len;
 	size_t len = fanotify_event_info_len(event);
 
@@ -233,7 +234,16 @@ static int copy_fid_to_user(struct fanotify_event *event, char __user *buf)
 
 	buf += sizeof(handle);
 	len -= sizeof(handle);
-	if (copy_to_user(buf, fanotify_event_fh(event), fh_len))
+	/*
+	 * For an inline fh, copy through stack to exclude the copy from
+	 * usercopy hardening protections.
+	 */
+	fh = fanotify_event_fh(event);
+	if (fh_len <= FANOTIFY_INLINE_FH_LEN) {
+		memcpy(bounce, fh, fh_len);
+		fh = bounce;
+	}
+	if (copy_to_user(buf, fh, fh_len))
 		return -EFAULT;
 
 	/* Pad with 0's */

fs/notify/inotify/inotify_user.c

@@ -519,8 +519,10 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 	fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group);
 	if (!fsn_mark)
 		return -ENOENT;
-	else if (create)
-		return -EEXIST;
+	else if (create) {
+		ret = -EEXIST;
+		goto out;
+	}
 
 	i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
 
@@ -548,6 +550,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 	/* return the wd */
 	ret = i_mark->wd;
 
+out:
 	/* match the get from fsnotify_find_mark() */
 	fsnotify_put_mark(fsn_mark);