Ansible Role: sshd

Description

This role provides secure ssh-client and ssh-server configurations. It is intended to be compliant with the DevSec SSH Baseline.

Installation

ansible-galaxy install arillso.sshd

Requirements

None

Role Variables

Name	Default Value	Description
network_ipv6_enable	false	true if IPv6 is needed
ssh_client_cbc_required	false	true if CBC for ciphers is required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure ciphers enabled. CBC is a weak alternative. Anything weaker should be avoided and is thus not available.
ssh_server_cbc_required	false	true if CBC for ciphers is required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure ciphers enabled. CBC is a weak alternative. Anything weaker should be avoided and is thus not available.
ssh_client_weak_hmac	false	true if weaker HMAC mechanisms are required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure HMACs enabled.
ssh_server_weak_hmac	false	true if weaker HMAC mechanisms are required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure HMACs enabled.
ssh_client_weak_kex	false	true if weaker Key-Exchange (KEX) mechanisms are required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure KEXs enabled.
ssh_server_weak_kex	false	true if weaker Key-Exchange (KEX) mechanisms are required. This is usually only necessary, if older M2M mechanism need to communicate with SSH, that don't have any of the configured secure KEXs enabled.
ssh_server_ports	['22']	ports on which ssh-server should listen
ssh_client_port	'22'	port to which ssh-client should connect
ssh_listen_to	['0.0.0.0']	one or more ip addresses, to which ssh-server should listen to. Default is all adresseses, but should be configured to specific addresses for security reasons!
ssh_host_key_files	[]	Host keys for sshd. If empty ['/etc/ssh/ssh_host_rsa_key', '/etc/ssh/ssh_host_ecdsa_key', '/etc/ssh/ssh_host_ed25519_key'] will be used, as far as supported by the installed sshd version
ssh_client_alive_interval	600	specifies an interval for sending keepalive messages
ssh_client_alive_count	3	defines how often keep-alive messages are sent
ssh_permit_tunnel	false	true if SSH Port Tunneling is required
ssh_remote_hosts	[]	one or more hosts and their custom options for the ssh-client. Default is empty. See examples in defaults/main.yml.
ssh_empty_passwords	false	false when user not logged in wehn not password set.
ssh_allow_root_with_key	false	false to disable root login altogether. Set to true to allow root to login via key-based mechanism.
ssh_allow_tcp_forwarding	false	false to disable TCP Forwarding. Set to true to allow TCP Forwarding.
ssh_allow_agent_forwarding	false	false to disable Agent Forwarding. Set to true to allow Agent Forwarding.
ssh_use_pam	false	false to disable pam authentication.
ssh_deny_users	''	if specified, login is disallowed for user names that match one of the patterns.
ssh_allow_users	''	if specified, login is allowed only for user names that match one of the patterns.
ssh_deny_groups	''	if specified, login is disallowed for users whose primary group or supplementary group list matches one of the patterns.
ssh_allow_groups	''	if specified, login is allowed only for users whose primary group or supplementary group list matches one of the patterns.
ssh_print_motd	false	false to disable printing of the MOTD
ssh_print_last_log	false	false to disable display of last login information
sftp_enabled	true	false to disable sftp configuration
sftp_chroot_dir	/home/%u	change default sftp chroot location
ssh_client_roaming	false	enable experimental client roaming
sshd_moduli_minimum	2048	remove Diffie-Hellman parameters smaller than the defined size to mitigate logjam
ssh_challengeresponseauthentication	false	Specifies whether challenge-response authentication is allowed (e.g. via PAM)
ssh_client_password_login	false	true to allow password-based authentication with the ssh client
ssh_server_password_login	false	true to allow password-based authentication with the ssh server
ssh_banner	false	true to print a banner on login
ssh_client_hardening	true	false to stop harden the client
ssh_client_port	'22'	Specifies the port number to connect on the remote host.
ssh_compression	false	Specifies whether compression is enabled after the user has authenticated successfully.
ssh_max_auth_retries	2	Specifies the maximum number of authentication attempts permitted per connection.
ssh_print_debian_banner	false	true to print debian specific banner
ssh_server_enabled	true	false to disable the opensshd server
ssh_server_hardening	true	false to stop harden the server
ssh_server_match_group	''	Introduces a conditional block. If all of the criteria on the Match line are satisfied, the keywords on the following lines override those set in the global section of the config file, until either another Match line or the end of the file.
ssh_server_match_user	''	Introduces a conditional block. If all of the criteria on the Match line are satisfied, the keywords on the following lines override those set in the global section of the config file, until either another Match line or the end of the file.
ssh_server_permit_environment_vars	false	true to specify that ~/.ssh/environment and environment= options in ~/.ssh/authorized_keys are processed by sshd
ssh_use_dns	false	Specifies whether sshd should look up the remote host name, and to check that the resolved host name for the remote IP address maps back to the very same IP address.
ssh_server_revoked_keys	[]	a list of revoked public keys that the ssh server will always reject, useful to revoke known weak or compromised keys.
ssh_server_x11_forwarding	false	true to enable X11Forwarding
ssh_server_GSSAPI_auth	false	true to enable GSSAPIAuthentication

Dependencies

None

Example Playbook

- hosts: all
  roles:
    - arillso.sshd

Changelog

1.6

• added option to enable sshd X11Forwarding

1.5

• add ssh_ciphers

1.4

• update loop_vars

1.3

• new travis check
• syntax clean

1.2

• rename role name
• update meta

1.1

• add option when no password set by login
• add restart sshd by port change
• default value when ansible_ssh_port not set

1.0

• Initial release

Author

• Simon Bärlocher

License

This project is under the MIT License. See the LICENSE file for the full license text.

Copyright

(c) 2019, Simon Bärlocher