roles/common: port common settings to Debian 11 sshd_config

Still need to add the encryption settings.

roles/common/templates/sshd_config_Debian-11.j2

@@ -18,28 +18,29 @@ Include /etc/ssh/sshd_config.d/*.conf
 #ListenAddress ::
 
 #HostKey /etc/ssh/ssh_host_rsa_key
-#HostKey /etc/ssh/ssh_host_ecdsa_key
-#HostKey /etc/ssh/ssh_host_ed25519_key
+HostKey /etc/ssh/ssh_host_ed25519_key
 
 # Ciphers and keying
 #RekeyLimit default none
 
 # Logging
 #SyslogFacility AUTH
-#LogLevel INFO
+# LogLevel VERBOSE logs user's key fingerprint on login. Needed to have a clear audit track of which key was using to log in.
+LogLevel VERBOSE
 
 # Authentication:
 
 #LoginGraceTime 2m
-#PermitRootLogin prohibit-password
+PermitRootLogin prohibit-password
 #StrictModes yes
-#MaxAuthTries 6
+MaxAuthTries 4
 #MaxSessions 10
 
 #PubkeyAuthentication yes
 
-# Expect .ssh/authorized_keys2 to be disregarded by default in future.
-#AuthorizedKeysFile	.ssh/authorized_keys .ssh/authorized_keys2
+# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
+# but this is overridden so installations will only check .ssh/authorized_keys
+AuthorizedKeysFile	.ssh/authorized_keys
 
 #AuthorizedPrincipalsFile none
 
@@ -88,7 +89,7 @@ UsePAM yes
 #AllowAgentForwarding yes
 #AllowTcpForwarding yes
 #GatewayPorts no
-X11Forwarding yes
+X11Forwarding no
 #X11DisplayOffset 10
 #X11UseLocalhost yes
 #PermitTTY yes
@@ -121,3 +122,6 @@ Subsystem	sftp	/usr/lib/openssh/sftp-server
 #	AllowTcpForwarding no
 #	PermitTTY no
 #	ForceCommand cvs server
+
+# only allow shell access by provisioning user
+AllowUsers {{ provisioning_user.name }}