[CVE-2018-1000115] memcached: restrict to TCP & internal_api network

https://access.redhat.com/security/cve/cve-2018-1000115

Restrict Memcached to only work on TCP and internal_api network.
The restriction is made at the application and firewall levels.
It will prevent DDoS amplification attacks using memcached.

Change-Id: I8fb81d7f3938b04ff7652e30de35a1ec23ae723d
Related-Bug: #1754607

puppet/services/memcached.yaml

@@ -49,8 +49,16 @@ parameters:
     type: string
     constraints:
       - allowed_values: [ '', 'true', 'True', 'TRUE', 'false', 'False', 'FALSE']
+  MemcachedIpSubnet:
+    default: ''
+    description: IP address/subnet on the memcached network. If empty (default), MemcachedNetwork
+                 will be taken. Useful in the case where an operator wants to open Memcached outside
+                 of the internal network. Use this parameter with caution and be aware of
+                 opening memcached to external network can be dangerous.
+    type: string
 
 conditions:
+  memcached_network_unset: {equals : [{get_param: MemcachedIpSubnet}, '']}
   service_debug:
     or:
       - equals: [{get_param: MemcachedDebug}, 'true']
@@ -64,6 +72,11 @@ outputs:
       service_name: memcached
       monitoring_subscription: {get_param: MonitoringSubscriptionMemcached}
       config_settings:
+        memcached_network:
+          str_replace:
+            template: "NETWORK_subnet"
+            params:
+              NETWORK: {get_param: [ServiceNetMap, MemcachedNetwork]}
         # NOTE: bind IP is found in hiera replacing the network name with the local node IP
         # for the given network; replacement examples (eg. for internal_api):
         # internal_api -> IP
@@ -76,6 +89,9 @@ outputs:
             params:
               $NETWORK: {get_param: [ServiceNetMap, MemcachedNetwork]}
         memcached::max_memory: {get_param: MemcachedMaxMemory}
+        # https://access.redhat.com/security/cve/cve-2018-1000115
+        # Only accept TCP to avoid spoofed traffic amplification DoS on UDP.
+        memcached::udp_port: 0
         memcached::verbosity:
           list_join:
             - ''
@@ -87,6 +103,17 @@ outputs:
         tripleo.memcached.firewall_rules:
           '121 memcached':
             dport: 11211
+            # https://access.redhat.com/security/cve/cve-2018-1000115
+            # Only accept TCP to avoid spoofed traffic amplification DoS on UDP.
+            proto: 'tcp'
+            # Memcached traffic shouldn't be open on the internet.
+            # Even if binding is configured on internal_api network, enforce it
+            # via firewall as well.
+            source:
+              if:
+              - memcached_network_unset
+              - "%{hiera('memcached_network')}"
+              - {get_param: MemcachedIpSubnet}
       step_config: |
         include ::tripleo::profile::base::memcached
       service_config_settings:

releasenotes/notes/memcached_hardening-2529734099da27f4.yaml

@@ -0,0 +1,4 @@
+---
+security:
+  - |
+    Restrict memcached service to TCP and internal_api network (CVE-2018-1000115).