# Author: Mike Milner <mike.milner@canonical.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
"""
CA Certs
--------
**Summary:** add ca certificates
This module adds CA certificates to ``/etc/ca-certificates.conf`` and updates
the ssl cert cache using ``update-ca-certificates``. The default certificates
can be removed from the system with the configuration option
``remove-defaults``.
.. note::
certificates must be specified using valid yaml. in order to specify a
multiline certificate, the yaml multiline list syntax must be used
.. note::
For Alpine Linux the "remove-defaults" functionality works if the
ca-certificates package is installed but not if the
ca-certificates-bundle package is installed.
**Internal name:** ``cc_ca_certs``
**Module frequency:** per instance
**Supported distros:** alpine, debian, ubuntu, rhel
**Config keys**::
ca-certs:
remove-defaults: <true/false>
trusted:
- <single line cert>
- |
-----BEGIN CERTIFICATE-----
YOUR-ORGS-TRUSTED-CA-CERT-HERE
-----END CERTIFICATE-----
"""
import os
from cloudinit import subp
from cloudinit import util
DEFAULT_CONFIG = {
'ca_cert_path': '/usr/share/ca-certificates/',
'ca_cert_filename': 'cloud-init-ca-certs.crt',
'ca_cert_config': '/etc/ca-certificates.conf',
'ca_cert_system_path': '/etc/ssl/certs/',
'ca_cert_update_cmd': ['update-ca-certificates']
}
DISTRO_OVERRIDES = {
'rhel': {
'ca_cert_path': '/usr/share/pki/ca-trust-source/',
'ca_cert_filename': 'anchors/cloud-init-ca-certs.crt',
'ca_cert_config': None,
'ca_cert_system_path': '/etc/pki/ca-trust/',
'ca_cert_update_cmd': ['update-ca-trust']
}
}
distros = ['alpine', 'debian', 'ubuntu', 'rhel']
def _distro_ca_certs_configs(distro_name):
"""Return a distro-specific ca_certs config dictionary
@param distro_name: String providing the distro class name.
@returns: Dict of distro configurations for ca-cert.
"""
cfg = DISTRO_OVERRIDES.get(distro_name, DEFAULT_CONFIG)
cfg['ca_cert_full_path'] = os.path.join(cfg['ca_cert_path'],
cfg['ca_cert_filename'])
return cfg
def update_ca_certs(distro_cfg):
"""
Updates the CA certificate cache on the current machine.
@param distro_cfg: A hash providing _distro_ca_certs_configs function.
"""
subp.subp(distro_cfg['ca_cert_update_cmd'], capture=False)
def add_ca_certs(distro_cfg, certs):
"""
Adds certificates to the system. To actually apply the new certificates
you must also call L{update_ca_certs}.
@param distro_cfg: A hash providing _distro_ca_certs_configs function.
@param certs: A list of certificate strings.
"""
if not certs:
return
# First ensure they are strings...
cert_file_contents = "\n".join([str(c) for c in certs])
util.write_file(distro_cfg['ca_cert_full_path'],
cert_file_contents,
mode=0o644)
update_cert_config(distro_cfg)
def update_cert_config(distro_cfg):
"""
Update Certificate config file to add the file path managed cloud-init
@param distro_cfg: A hash providing _distro_ca_certs_configs function.
"""
if distro_cfg['ca_cert_config'] is None:
return
if os.stat(distro_cfg['ca_cert_config']).st_size == 0:
# If the CA_CERT_CONFIG file is empty (i.e. all existing
# CA certs have been deleted) then simply output a single
# line with the cloud-init cert filename.
out = "%s\n" % distro_cfg['ca_cert_filename']
else:
# Append cert filename to CA_CERT_CONFIG file.
# We have to strip the content because blank lines in the file
# causes subsequent entries to be ignored. (LP: #1077020)
orig = util.load_file(distro_cfg['ca_cert_config'])
cr_cont = '\n'.join([line for line in orig.splitlines()
if line != distro_cfg['ca_cert_filename']])
out = "%s\n%s\n" % (cr_cont.rstrip(),
distro_cfg['ca_cert_filename'])
util.write_file(distro_cfg['ca_cert_config'], out, omode="wb")
def remove_default_ca_certs(distro_name, distro_cfg):
"""
Removes all default trusted CA certificates from the system. To actually
apply the change you must also call L{update_ca_certs}.
@param distro_name: String providing the distro class name.
@param distro_cfg: A hash providing _distro_ca_certs_configs function.
"""
util.delete_dir_contents(distro_cfg['ca_cert_path'])
util.delete_dir_contents(distro_cfg['ca_cert_system_path'])
util.write_file(distro_cfg['ca_cert_config'], "", mode=0o644)
if distro_name in ['debian', 'ubuntu']:
debconf_sel = (
"ca-certificates ca-certificates/trust_new_crts " + "select no")
subp.subp(('debconf-set-selections', '-'), debconf_sel)
def handle(name, cfg, cloud, log, _args):
"""
Call to handle ca-cert sections in cloud-config file.
@param name: The module name "ca-cert" from cloud.cfg
@param cfg: A nested dict containing the entire cloud config contents.
@param cloud: The L{CloudInit} object in use.
@param log: Pre-initialized Python logger object to use for logging.
@param args: Any module arguments from cloud.cfg
"""
# If there isn't a ca-certs section in the configuration don't do anything
if "ca-certs" not in cfg:
log.debug(("Skipping module named %s,"
" no 'ca-certs' key in configuration"), name)
return
ca_cert_cfg = cfg['ca-certs']
distro_cfg = _distro_ca_certs_configs(cloud.distro.name)
# If there is a remove-defaults option set to true, remove the system
# default trusted CA certs first.
if ca_cert_cfg.get("remove-defaults", False):
log.debug("Removing default certificates")
remove_default_ca_certs(cloud.distro.name, distro_cfg)
# If we are given any new trusted CA certs to add, add them.
if "trusted" in ca_cert_cfg:
trusted_certs = util.get_cfg_option_list(ca_cert_cfg, "trusted")
if trusted_certs:
log.debug("Adding %d certificates" % len(trusted_certs))
add_ca_certs(distro_cfg, trusted_certs)
# Update the system with the new cert configuration.
log.debug("Updating certificates")
update_ca_certs(distro_cfg)
# vi: ts=4 expandtab