diff --git a/fs/ntfs3/dir.c b/fs/ntfs3/dir.c
index 62482c2352ad..6f8ad8428f49 100644
--- a/fs/ntfs3/dir.c
+++ b/fs/ntfs3/dir.c
@@ -25,6 +25,11 @@ int ntfs_utf16_to_nls(struct ntfs_sb_info *sbi, const __le16 *name, u32 len,
 
 	static_assert(sizeof(wchar_t) == sizeof(__le16));
 
+	if (buf_len <= 0)
+		return -EINVAL;
+
+	buf_len -= 1;
+
 	if (!nls) {
 		/* UTF-16 -> UTF-8 */
 		ret = utf16s_to_utf8s((wchar_t *)name, len, UTF16_LITTLE_ENDIAN,