diff --git a/ext/ftp/ftp.c b/ext/ftp/ftp.c
index ffe955766bc..39555d8c7e3 100644
--- a/ext/ftp/ftp.c
+++ b/ext/ftp/ftp.c
@@ -573,12 +573,12 @@ bool ftp_rmdir(ftpbuf_t *ftp, const char *dir, const size_t dir_len)
 	return true;
 }
 
-bool ftp_chmod(ftpbuf_t *ftp, const int mode, const char *filename, const int filename_len)
+bool ftp_chmod(ftpbuf_t *ftp, const int mode, const char *filename, const size_t filename_len)
 {
 	char *buffer;
 	size_t buffer_len;
 
-	if (ftp == NULL || filename_len <= 0) {
+	if (ftp == NULL || filename_len == 0) {
 		return false;
 	}
 
diff --git a/ext/ftp/ftp.h b/ext/ftp/ftp.h
index 0e73ee30850..5f01f202b8e 100644
--- a/ext/ftp/ftp.h
+++ b/ext/ftp/ftp.h
@@ -138,7 +138,7 @@ zend_string* ftp_mkdir(ftpbuf_t *ftp, const char *dir, const size_t dir_len);
 bool ftp_rmdir(ftpbuf_t *ftp, const char *dir, const size_t dir_len);
 
 /* Set permissions on a file */
-bool ftp_chmod(ftpbuf_t *ftp, const int mode, const char *filename, const int filename_len);
+bool ftp_chmod(ftpbuf_t *ftp, const int mode, const char *filename, const size_t filename_len);
 
 /* Allocate space on remote server with ALLO command
  * Many servers will respond with 202 Allocation not necessary,