--- tftpd.c.orig	2023-04-11 16:42:55.548613000 +0700
+++ tftpd.c	2023-07-20 10:04:41.193372000 +0700
@@ -100,6 +100,7 @@ static struct dirlist {
 static int	suppress_naks;
 static int	logging;
 static int	ipchroot;
+static int	check_woth = 1;
 static int	create_new = 0;
 static const char *newfile_format = "%Y%m%d";
 static int	increase_name = 0;
@@ -141,7 +142,7 @@ main(int argc, char *argv[])
 	acting_as_client = 0;
 
 	tftp_openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
-	while ((ch = getopt(argc, argv, "cCd::F:lnoOp:s:u:U:wW")) != -1) {
+	while ((ch = getopt(argc, argv, "cCd::F:lnoOp:sS:u:U:wW")) != -1) {
 		switch (ch) {
 		case 'c':
 			ipchroot = 1;
@@ -181,6 +182,9 @@ main(int argc, char *argv[])
 		case 's':
 			chroot_dir = optarg;
 			break;
+		case 'S':
+			check_woth = -1;
+			break;
 		case 'u':
 			chuser = optarg;
 			break;
@@ -361,7 +365,11 @@ main(int argc, char *argv[])
 			tftp_log(LOG_ERR, "setuid failed");
 			exit(1);
 		}
+		if (check_woth == -1)
+			check_woth = 0;
 	}
+	if (check_woth == -1)
+		check_woth = 1;
 
 	len = sizeof(me_sock);
 	if (getsockname(0, (struct sockaddr *)&me_sock, &len) == 0) {
@@ -704,7 +712,7 @@ validate_access(int peer, char **filep, int mode)
 			if ((stbuf.st_mode & S_IROTH) == 0)
 				return (EACCESS);
 		} else {
-			if ((stbuf.st_mode & S_IWOTH) == 0)
+			if (check_woth && ((stbuf.st_mode & S_IWOTH) == 0))
 				return (EACCESS);
 		}
 	} else {
@@ -734,7 +742,7 @@ validate_access(int peer, char **filep, int mode)
 					if ((stbuf.st_mode & S_IROTH) != 0)
 						break;
 				} else {
-					if ((stbuf.st_mode & S_IWOTH) != 0)
+					if (!check_woth || ((stbuf.st_mode & S_IWOTH) != 0))
 						break;
 				}
 				err = EACCESS;