From dcdc4f3ea27f1a26f8baa6b72b51c7911f21e6ba Mon Sep 17 00:00:00 2001
From: Christian Poessinger <christian@poessinger.com>
Date: Thu, 7 Jan 2021 23:22:58 +0100
Subject: ssh: T2635: harden Jinja2 template and daemon startup

---
 data/templates/ssh/sshd_config.tmpl | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

(limited to 'data/templates')

diff --git a/data/templates/ssh/sshd_config.tmpl b/data/templates/ssh/sshd_config.tmpl
index 1dc700d38..7d7257cae 100644
--- a/data/templates/ssh/sshd_config.tmpl
+++ b/data/templates/ssh/sshd_config.tmpl
@@ -48,59 +48,59 @@ LogLevel {{ loglevel | upper }}
 # Specifies whether password authentication is allowed
 PasswordAuthentication {{ "no" if disable_password_authentication is defined else "yes" }}
 
-{% if listen_address %}
+{% if listen_address is defined and listen_address is not none %}
 # Specifies the local addresses sshd should listen on
 {%   for address in listen_address %}
 ListenAddress {{ address }}
 {%   endfor %}
 {% endif %}
 
-{% if ciphers %}
+{% if ciphers is defined and ciphers is not none %}
 # Specifies the ciphers allowed for protocol version 2
-{% set value = ciphers if ciphers is string else ciphers | join(',') %}
+{%   set value = ciphers if ciphers is string else ciphers | join(',') %}
 Ciphers {{ value }}
 {% endif %}
 
-{% if mac %}
+{% if mac is defined and mac is not none %}
 # Specifies the available MAC (message authentication code) algorithms
-{% set value = mac if mac is string else mac | join(',') %}
+{%   set value = mac if mac is string else mac | join(',') %}
 MACs {{ value }}
 {% endif %}
 
-{% if key_exchange %}
+{% if key_exchange is defined and key_exchange is not none %}
 # Specifies the available Key Exchange algorithms
-{% set value = key_exchange if key_exchange is string else key_exchange | join(',') %}
+{%   set value = key_exchange if key_exchange is string else key_exchange | join(',') %}
 KexAlgorithms {{ value }}
 {% endif %}
 
-{% if access_control is defined %}
-{%   if access_control.allow is defined %}
+{% if access_control is defined and access_control is not none %}
+{%   if access_control.allow is defined and access_control.allow is not none %}
 {%     if access_control.allow.user is defined %}
 # If specified, login is allowed only for user names that match
-{% set value = access_control.allow.user if access_control.allow.user is string else access_control.allow.user | join(' ') %}
+{%       set value = access_control.allow.user if access_control.allow.user is string else access_control.allow.user | join(' ') %}
 AllowUsers {{ value }}
 {%     endif %}
 {%     if access_control.allow.group is defined %}
 # If specified, login is allowed only for users whose primary group or supplementary group list matches
-{% set value = access_control.allow.group if access_control.allow.group is string else access_control.allow.group | join(' ') %}
+{%       set value = access_control.allow.group if access_control.allow.group is string else access_control.allow.group | join(' ') %}
 AllowGroups {{ value }}
 {%     endif %}
 {%   endif %}
-{%   if access_control.deny is defined %}
+{%   if access_control.deny is defined and access_control.deny is not none %}
 {%     if access_control.deny.user is defined %}
 # Login is disallowed for user names that match
-{% set value = access_control.deny.user if access_control.deny.user is string else access_control.deny.user | join(' ') %}
+{%        set value = access_control.deny.user if access_control.deny.user is string else access_control.deny.user | join(' ') %}
 DenyUsers {{ value }}
 {%     endif %}
 {%     if access_control.deny.group is defined %}
 # Login is disallowed for users whose primary group or supplementary group list matches
-{% set value = access_control.deny.group if access_control.deny.group is string else access_control.deny.group | join(' ') %}
+{%        set value = access_control.deny.group if access_control.deny.group is string else access_control.deny.group | join(' ') %}
 DenyGroups {{ value }}
 {%     endif %}
 {%   endif %}
 {% endif %}
 
-{% if client_keepalive_interval %}
+{% if client_keepalive_interval is defined and client_keepalive_interval is not none %}
 # Sets a timeout interval in seconds after which if no data has been received from the client,
 # sshd(8) will send a message through the encrypted channel to request a response from the client
 ClientAliveInterval {{ client_keepalive_interval }}
-- 
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