Add config for ssh-key import and consuming user-data

This patch enables control over SSH public-key import and
discarding supplied user-data (both disabled by default).

  allow-userdata: false
  ssh:
    allow_public_ssh_keys: false

This feature enables closed appliances to prevent customers
from unintentionally breaking the appliance which were
not designed for user interaction.

The downstream change for this is here:
  https://github.com/delphix/cloud-init/pull/4

1 files changed, 13 insertions, 2 deletions

diff --git a/cloudinit/config/cc_ssh.py b/cloudinit/config/cc_ssh.py
index fdd8f4d3..050285a8 100755
--- a/cloudinit/config/cc_ssh.py
+++ b/cloudinit/config/cc_ssh.py
@@ -56,9 +56,13 @@ root login is disabled, and root login opts are set to::
     no-port-forwarding,no-agent-forwarding,no-X11-forwarding
 
 Authorized keys for the default user/first user defined in ``users`` can be
-specified using `ssh_authorized_keys``. Keys should be specified as a list of
+specified using ``ssh_authorized_keys``. Keys should be specified as a list of
 public keys.
 
+Importing ssh public keys for the default user (defined in ``users``)) is
+enabled by default.  This feature may be disabled by setting
+``allow_publish_ssh_keys: false``.
+
 .. note::
     see the ``cc_set_passwords`` module documentation to enable/disable ssh
     password authentication
@@ -91,6 +95,7 @@ public keys.
     ssh_authorized_keys:
         - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAGEA3FSyQwBI6Z+nCSjUU ...
         - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA3I7VUf2l5gSn5uavROsc5HRDpZ ...
+    allow_public_ssh_keys: <true/false>
     ssh_publish_hostkeys:
         enabled: <true/false> (Defaults to true)
         blacklist: <list of key types> (Defaults to [dsa])
@@ -207,7 +212,13 @@ def handle(_name, cfg, cloud, log, _args):
         disable_root_opts = util.get_cfg_option_str(cfg, "disable_root_opts",
                                                     ssh_util.DISABLE_USER_OPTS)
 
-        keys = cloud.get_public_ssh_keys() or []
+        keys = []
+        if util.get_cfg_option_bool(cfg, 'allow_public_ssh_keys', True):
+            keys = cloud.get_public_ssh_keys() or []
+        else:
+            log.debug('Skipping import of publish ssh keys per '
+                      'config setting: allow_public_ssh_keys=False')
+
         if "ssh_authorized_keys" in cfg:
             cfgkeys = cfg["ssh_authorized_keys"]
             keys.extend(cfgkeys)