dns-extern: role for primary nameserver

group_vars/all/vars.yml

@@ -2,6 +2,10 @@
 
 certmgr_mode: webserver
 
+dns_axfr_ips:
+- 216.218.133.2
+- 2001:470:600::2
+
 dss_domain: dss.binary-kitchen.de
 
 gogs_domain: git.binary-kitchen.de

roles/dns-extern/files/updatepolicy.aliases

@@ -0,0 +1,9 @@
+--
+-- Define additional domains to allow (acme) updates for with an exisiting TSIG key
+--
+-- Line format:
+--   alias["<domain-from-TSIG-key>"] = { "<san-domain1>", ... }
+--
+-- WARNING: Trailing "." are important for correct validation on all used names
+--
+--

roles/dns-extern/files/updatepolicy.lua

@@ -0,0 +1,58 @@
+function loadaliasesfromfile()
+  local env = { alias = {} }
+  local f,err = loadfile("/etc/powerdns/updatepolicy.aliases", "t", env)
+  if f then
+    f() -- run the loaded code in the prepared env for safety reasons
+    pdnslog("Successfully loaded alias config", pdns.loglevels.Debug)
+  else
+    pdnslog("Failed to load alias config: "..err, pdns.loglevels.Warning)
+ end
+  return env.alias
+end
+
+function getacmedomains(domain)
+  -- Add domain as the first entry to the list
+  local domains = {[0] = "_acme-challenge."..domain}
+  local counter = 1
+  -- Load additional alias domains from config file
+  local aliases = loadaliasesfromfile()
+  if aliases[domain] ~= nil then
+    for _,alias in pairs(aliases[domain]) do
+      domains[counter] = "_acme-challenge."..alias
+      counter = counter + 1
+    end
+  end
+  -- Return all challenge domains
+  return domains
+end
+
+function updatepolicy(input)
+  -- Check for valid TSIG key or fail
+  local key = input:getTsigName()
+  local keyname = nil
+  if key == nil or not pcall(function() keyname = key:toString() end) or keyname == "" then
+    -- fail on no key (and work around the possible odd exception with pcall)
+    pdnslog("No TSIG key found. Update rejected.", pdns.loglevels.Error)
+    return false
+  end
+
+  -- Process ACME keys
+  local pos,_,domain = string.find(keyname, "^acme%-(.+)")
+  if pos ~= nil then
+    for _,acmedomain in pairs(getacmedomains(domain)) do
+      pdnslog("Validating against "..acmedomain, pdns.loglevels.Debug)
+      if input:getQType() == pdns.TXT and input:getQName():toString():lower() == acmedomain:lower() then
+        -- valid acme key with matching domain matches name and TXT
+        pdnslog("ACME TSIG '"..keyname.."' key found and request matches domain or known aliases. Update permitted.")
+        return true
+      end
+    end
+    -- acme key and no valid match
+    pdnslog("ACME TSIG '"..keyname.."' key found but request does not match domain or known aliases. Update rejected.", pdns.loglevels.Error)
+    return false
+  end
+
+  -- Process other keys with the normal default policy result
+  pdnslog("TSIG Key '"..keyname.."' found. Update permitted.")
+  return true
+end

roles/dns-extern/handlers/main.yml

@@ -0,0 +1,4 @@
+---
+
+- name: Restart powerdns
+  service: name=pdns state=restarted

roles/dns-extern/tasks/main.yml

@@ -0,0 +1,21 @@
+---
+
+- name: Install powerdns
+  apt: name={{ item }}
+  with_items:
+   - pdns-server
+   - pdns-backend-sqlite3
+
+- name: Configure powerdns
+  template: src=pdns.conf.j2 dest=/etc/powerdns/pdns.conf
+  notify: Restart powerdns
+
+- name: Copy update policy script
+  copy: src=updatepolicy.lua dest=/etc/powerdns/updatepolicy.lua
+  notify: Restart powerdns
+
+- name: Initialize update policy alias list
+  copy: src=updatepolicy.aliases dest=/etc/powerdns/updatepolicy.aliases force=no
+
+- name: Start the powerdns services
+  service: name=pdns state=started enabled=yes

roles/dns-extern/templates/pdns.conf.j2

@@ -0,0 +1,13 @@
+local-address=0.0.0.0
+local-ipv6=::
+launch=gsqlite3
+gsqlite3-dnssec
+gsqlite3-database=/var/lib/powerdns/powerdns.sqlite3
+master
+slave-cycle-interval=30
+dnsupdate=yes
+only-notify=
+allow-axfr-ips=127.0.0.1,::1{% if dns_axfr_ips is defined %},{{ dns_axfr_ips | join(',') }}
+{% endif %}
+allow-dnsupdate-from=0.0.0.0/0,::/0
+lua-dnsupdate-policy-script=/etc/powerdns/updatepolicy.lua

site.yml

@@ -87,4 +87,4 @@
 - name: Setup primary dns server
   hosts: neon.binary-kitchen.net
   roles:
-#  - dns-extern
+  - dns-extern