port of:

From f2aa49e7fda515163da188ec75dba223e2e52216 Mon Sep 17 00:00:00 2001
From: Brooks Davis <brooks@FreeBSD.org>
Date: Mon, 26 Sep 2022 18:56:51 +0100
Subject: telnetd: fix two-byte input crash

Move initialization of the slc table earlier so it doesn't get
accessed before that happens.

For details on the issue, see:
https://pierrekim.github.io/blog/2022-08-24-2-byte-dos-freebsd-netbsd-telnetd-netkit-telnetd-inetutils-telnetd-kerberos-telnetd.html

Reviewed by:	cy
Obtained from:	NetBSD via cy
Differential Revision:	https://reviews.freebsd.org/D36680

(cherry picked from commit 6914ffef4e2318ca1d0ead28eafb6f06055ce0f8)
---
 contrib/telnet/telnetd/telnetd.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/contrib/telnet/telnetd/telnetd.c b/contrib/telnet/telnetd/telnetd.c
index 522877829735..e12fe70997ab 100644
--- a/contrib/telnet/telnetd/telnetd.c
+++ b/contrib/telnet/telnetd/telnetd.c
@@ -647,6 +647,11 @@ doit(struct sockaddr *who, socklen_t who
 	char user_name[256];
 
 	/*
+	 * Initialize the slc mapping table.
+	 */
+	get_slc_defaults();
+
+	/*
 	 * Find an available pty to use.
 	 */
 	pty = getpty();
@@ -757,10 +762,6 @@ void telnet(int f, int p)
     const char *IM;
     int pty_read_ok = 0; /* track whether the pty read has worked yet */
 
-    /*
-     * Initialize the slc mapping table.
-     */
-    get_slc_defaults();
 	CHECK_CLEANUP;
 
     /*
-- 
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