VMAccess: Add Azure Linux / Mariner support to _get_default_ssh_config_filename

As preparation for the release of Azure Linux 4.0, this patch adds
support for Azure Linux and CBL-Mariner to the VMAccess extension's
sshd_config reset functionality.

When 'az vm user reset-ssh' is triggered on Azure Linux (or
CBL-Mariner), _get_default_ssh_config_filename() falls through to the
generic 'default' resource file because NAME="Azure Linux" does not
match any of the existing distro regexes (centos, debian, fedora,
red hat, suse, ubuntu).

The 'default' resource file is a Debian/Ubuntu-era sshd_config that
causes the following problems on Azure Linux:

- SFTP broken: wrong Subsystem path (/usr/lib/openssh/sftp-server
  instead of /usr/libexec/openssh/sftp-server)
- Multiple deprecated directive warnings from sshd -t
- Unable to load host key: /etc/ssh/ssh_host_dsa_key (DSA removed)
- Include /etc/ssh/sshd_config.d/*.conf directive dropped, causing
  all sshd_config.d snippets (cloud-init, Azure) to be silently lost
- PasswordAuthentication explicitly set to yes
- PermitRootLogin uses old 'without-password' syntax

Changes:
1. Add 'azure\s?linux|mariner' regex to _get_default_ssh_config_filename()
   returning 'azurelinux_default'. This matches:
   - Azure Linux: NAME="Azure Linux"
   - CBL-Mariner: NAME="Common Base Linux Mariner"

2. Add resources/azurelinux_default: stock Azure Linux sshd_config.
   Clean config with no deprecated directives, correct SFTP path,
   and Include directive preserved.

Tested on an Azure Linux VM:
- sshd -t: 0 errors (vs 6 with 'default')
- SFTP Subsystem: /usr/libexec/openssh/sftp-server (correct)
- Include /etc/ssh/sshd_config.d/*.conf: preserved
- sshd restart: clean

Author: jonathanbrenes

VMAccess/resources/azurelinux_default

@@ -0,0 +1,132 @@
+#	$OpenBSD: sshd_config,v 1.105 2024/12/03 14:12:47 dtucker Exp $
+
+# This is the sshd server system-wide configuration file.  See
+# sshd_config(5) for more information.
+
+# This sshd was compiled with PATH=/usr/local/bin:/usr/bin
+
+# The strategy used for options in the default sshd_config shipped with
+# OpenSSH is to specify options with their default value where
+# possible, but leave them commented.  Uncommented options override the
+# default value.
+
+# To modify the system-wide sshd configuration, create a  *.conf  file under
+#  /etc/ssh/sshd_config.d/  which will be automatically included below
+Include /etc/ssh/sshd_config.d/*.conf
+
+# If you want to change the port on a SELinux system, you have to tell
+# SELinux about this change.
+# semanage port -a -t ssh_port_t -p tcp #PORTNUMBER
+#
+#Port 22
+#AddressFamily any
+#ListenAddress 0.0.0.0
+#ListenAddress ::
+
+#HostKey /etc/ssh/ssh_host_rsa_key
+#HostKey /etc/ssh/ssh_host_ecdsa_key
+#HostKey /etc/ssh/ssh_host_ed25519_key
+
+# Ciphers and keying
+#RekeyLimit default none
+
+# Logging
+#SyslogFacility AUTH
+#LogLevel INFO
+
+# Authentication:
+
+#LoginGraceTime 2m
+#PermitRootLogin prohibit-password
+#StrictModes yes
+#MaxAuthTries 6
+#MaxSessions 10
+
+#PubkeyAuthentication yes
+
+# 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
+
+#AuthorizedKeysCommand none
+#AuthorizedKeysCommandUser nobody
+
+# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
+#HostbasedAuthentication no
+# Change to yes if you don't trust ~/.ssh/known_hosts for
+# HostbasedAuthentication
+#IgnoreUserKnownHosts no
+# Don't read the user's ~/.rhosts and ~/.shosts files
+#IgnoreRhosts yes
+
+# To disable tunneled clear text passwords, change to "no" here!
+#PasswordAuthentication yes
+#PermitEmptyPasswords no
+
+# Change to "no" to disable keyboard-interactive authentication.  Depending on
+# the system's configuration, this may involve passwords, challenge-response,
+# one-time passwords or some combination of these and other methods.
+#KbdInteractiveAuthentication yes
+
+# Kerberos options
+#KerberosAuthentication no
+#KerberosOrLocalPasswd yes
+#KerberosTicketCleanup yes
+#KerberosGetAFSToken no
+#KerberosUseKuserok yes
+
+# GSSAPI options
+#GSSAPIAuthentication no
+#GSSAPICleanupCredentials yes
+#GSSAPIStrictAcceptorCheck yes
+#GSSAPIKeyExchange no
+#GSSAPIEnablek5users no
+
+# Set this to 'yes' to enable PAM authentication, account processing,
+# and session processing. If this is enabled, PAM authentication will
+# be allowed through the KbdInteractiveAuthentication and
+# PasswordAuthentication.  Depending on your PAM configuration,
+# PAM authentication via KbdInteractiveAuthentication may bypass
+# the setting of "PermitRootLogin prohibit-password".
+# If you just want the PAM account and session checks to run without
+# PAM authentication, then enable this but set PasswordAuthentication
+# and KbdInteractiveAuthentication to 'no'.
+# WARNING: 'UsePAM no' is not supported in this build and may cause several
+# problems.
+#UsePAM no
+
+#AllowAgentForwarding yes
+#AllowTcpForwarding yes
+#GatewayPorts no
+#X11Forwarding no
+#X11DisplayOffset 10
+#X11UseLocalhost yes
+#PermitTTY yes
+#PrintMotd yes
+#PrintLastLog yes
+#TCPKeepAlive yes
+#PermitUserEnvironment no
+#Compression delayed
+#ClientAliveInterval 0
+#ClientAliveCountMax 3
+#UseDNS no
+#PidFile /var/run/sshd.pid
+#MaxStartups 10:30:100
+#PermitTunnel no
+#ChrootDirectory none
+#VersionAddendum none
+
+# no default banner path
+#Banner none
+
+# override default of no subsystems
+Subsystem       sftp    /usr/libexec/openssh/sftp-server
+
+# Example of overriding settings on a per-user basis
+#Match User anoncvs
+#       X11Forwarding no
+#       AllowTcpForwarding no
+#       PermitTTY no
+#       ForceCommand cvs server

VMAccess/vmaccess.py

@@ -392,6 +392,8 @@ def _get_default_ssh_config_filename():
             return "debian_default"
         if re.search("fedora", OSName, re.IGNORECASE):
             return "fedora_default"
+        if re.search("azure\s?linux|mariner", OSName, re.IGNORECASE):
+            return "azurelinux_default"
         if re.search("red\s?hat", OSName, re.IGNORECASE):
             return "redhat_default"
         if re.search("suse", OSName, re.IGNORECASE):