Description of problem:

SSH login is allowed with MACs which is not present in /etc/ssh/sshd_config file on openssh server.

Version-Release number of selected component (if applicable):
kernel -> 4.18.0-477.15.1.el8_8.x86_64
openssh version -> openssh-8.0p1-17.el8_7.x86_64

How reproducible:

Openssh Server:
--------------
~]# ip addr | grep inet | grep enp0s8
    inet 192.168.56.118/24 brd 192.168.56.255 scope global dynamic noprefixroute enp0s8

~]# grep CRYPTO_POLICY /etc/sysconfig/sshd
CRYPTO_POLICY=

~]# update-crypto-policies --show
DEFAULT

~]# egrep MACs /etc/ssh/sshd_config 
MACs umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-sha1-etm,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-sha1

~]# sshd -T | grep macs
macs umac-128-etm,hmac-sha2-256-etm,hmac-sha2-512-etm,hmac-sha1-etm,umac-128,hmac-sha2-256,hmac-sha2-512,hmac-sha1

~]# ps -ef | grep sshd
root       10613   10609  0 08:21 ?        00:00:00 sshd: root@pts/1
root       11304       1  0 09:58 ?        00:00:00 /usr/sbin/sshd -D

~]# systemctl status sshd
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2023-07-18 09:58:41 EDT; 10min ago
     Docs: man:sshd(8)
           man:sshd_config(5)
 Main PID: 11304 (sshd)
    Tasks: 1 (limit: 11132)
   Memory: 2.7M
   CGroup: /system.slice/sshd.service
           └─11304 /usr/sbin/sshd -D

Jul 18 09:58:41 myhostname.redhat.com systemd[1]: Starting OpenSSH server daemon...
Jul 18 09:58:41 myhostname.redhat.com sshd[11304]: Server listening on 0.0.0.0 port 22.
Jul 18 09:58:41 myhostname.redhat.com sshd[11304]: Server listening on :: port 22.
Jul 18 09:58:41 myhostname.redhat.com systemd[1]: Started OpenSSH server daemon.
Jul 18 10:02:46 myhostname.redhat.com sshd[11333]: Accepted password for root from 192.168.56.1 port 58234 ssh2
Jul 18 10:02:46 myhostname.redhat.com sshd[11333]: pam_unix(sshd:session): session opened for user root by (uid=0

Login from client system:
------------------------
[dushyant@uge ~]$ ssh -oMACs=umac-64-etm root.56.118
root.56.118's password: 
Last login: Tue Jul 18 09:54:43 2023 from 192.168.56.1
[root@myhostname ~]# 


Actual results:

Event if the MACs is not present in /etc/ssh/sshd_config file the ssh login is possible.

Expected results:
SSH login with the particular MAC should not be allowed, if that MACs is not present in openssh server's /etc/ssh/sshd_config file.