Certificate cookbook

Description

This recipe automates the common task of managing x509 certificates and keys from encrypted Data Bags. This cookbook provides a flexible and re-usable LWRP which can be plugged into other recipes, such as the postfix or apache2 cookbooks.

Important note

The KITCHEN.md documents the test/integration files used to validate the certificate_manage LWRP converges correctly. Files in the test/integration should not be used in production. Files include a self-signed "snake oil" certificate/key and an encrypted_data_bag_secret file which are not secure to use beyond testing.

Requirements

You do need to prepare an encrypted data bag, containing the certificates, private keys, and CA bundles you wish to deploy to servers with the LWRP. I used Joshua Timberman's blog post, and the Opscode Wiki documentation as a reference in creating this cookbook.

First, create a data bag secret as follows. You need to manually copy the encrypted_data_bag_secret to /etc/chef on your servers, or place it there as part of your bootstrap process. For example, you may choose to do deploy the secret file with kickstart or preseed as part of the OS install process.

openssl rand -base64 512 > ~/.chef/encrypted_data_bag_secret

Second, create a data bag, the default data bag within the LWRP is named certificates. However, you may override this with the data_bag LWRP attribute.

knife data bag create certificates

You need to convert your certificate, private keys, and CA bundles into single-line blobs with literal \n characters. This is so it may be copy/pasted into your data bag. You can use sed or you can use a Perl or Ruby one-liner for this conversion.

cat <filename> | sed s/$/\\\\n/ | tr -d '\n'
-OR-
/usr/bin/env ruby -e 'p ARGF.read' <filename>
-OR-
perl -pe 's!(\x0d)?\x0a!\\n!g' <filename>

What we're trying to accomplish is converting this:

-----BEGIN CERTIFICATE-----
MIIEEDCCA3mgAwIBAgIJAO4rOcmpIFmPMA0GCSqGSIb3DQEBBQUAMIG3MQswCQYD
-----END CERTIFICATE-----

Into this:

-----BEGIN CERTIFICATE-----\nMIIEEDCCA3mgAwIBAgIJAO4rOcmpIFmPMA0GCSqGSIb3DQEBBQUAMIG3MQswCQYD\n-----END CERTIFICATE-----

Finally, you'll want to create the data bag object to contain your certs, keys, and optionally your CA root chain bundle. The default recipe uses the OHAI attribute hostname as a search_id. One can use an fqdn as the search_id. Older versions of Knife have a strict character filter list which prevents the use of . separators in data bag IDs.

The cookbook also contains an example wildcard recipe to use with wildcard certificates (*.example.com) certificates.

Hostname mail as data bag search_id:

knife data bag create certificates mail --secret-file ~/.chef/encrypted_data_bag_secret

The resulting encrypted data bag for a hostname should be structured like so. The chain id may be optional if your CA's root chain is already trusted by the server.

{
  "id": "mail",
  "cert": "-----BEGIN CERTIFICATE-----\nMail Certificate Here...",
  "key": "-----BEGIN PRIVATE KEY\nMail Private Key Here...",
  "chain": "-----BEGIN CERTIFICATE-----\nCA Root Chain Here..."
}

Wildcard certificate as data bag search_id:

knife data bag create certificates wildcard --secret-file ~/.chef/encrypted_data_bag_secret

The resulting encrypted data bag should be structured like so for a wildcard certificate. The chain id may be optional if your CA's root chain is already trusted by the server.

{
  "id": "wildcard",
  "cert": "-----BEGIN CERTIFICATE-----\nWildcard Certificate Here...",
  "key": "-----BEGIN PRIVATE KEY\nWildcard Private Key Here...",
  "chain": "-----BEGIN CERTIFICATE-----\nCA Root Chain Here..."
}

Recipes

This cookbook comes with three simple example recipes for using the certificate_manage LWRP.

default

Searches the data bag, certificates, for an object with an id matching node.hostname. Then the recipe places the decrypted certificates and keys in either /etc/pki/tls (RHEL family), or /etc/ssl (Debian family). The default owner and group owner of the resulting files are root.

The resulting files will be named {node.fqdn}.pem (cert), {node.fqdn}.key (key), and {node.hostname}-bundle.crt (CA Root chain).

wildcard

Same as the default recipe, except for the search id is wildcard. The resulting files will be named wildcard.pem (cert), wildcard.key (key), and wildcard-bundle.crt (CA Root chain)

manage_by_attributes

Retrieve search keys from attributes "certificate". Set ID and LWRP attributes to node attribute following...

"certificate": [
  {"self": null},
  {"mail": {
    "cert_path": "/etc/postfix/ssl",
     "owner": "postfix",
     "group": "postfix"
    }
  },
]

Resources/Providers

resources

The LWRP resource attributes are as follows.

• data_bag - Data bag index to search, defaults to certificates
• data_bag_secret - Path to the file with the data bag secret
• search_id - Data bag id to search for, defaults to provider name
• cert_path - Top-level SSL directory, defaults to vendor specific location
• cert_file - The basename of the x509 certificate, defaults to {node.fqdn}.pem
• key_file - The basename of the private key file, defaults to {node.fqdn}.key
• chain_file - The basename of the x509 certificate, defaults to {node.hostname}-bundle.crt
• nginx_cert - If true, combines server and CA certificates for nginx. Default false
• combined_file - If true, combines server cert, CA cert and private key into a single file. Default false
• owner - The file owner, defaults to root
• group - The file group owner, defaults to root
• cookbook - The cookbook containing the erb template, defaults to certificate
• create_subfolders - Enable/disable auto-creation of private/certs subdirectories. Defaults to true

Also exposed are several readonly attributes for helping in other recipes:

• certificate - The final path of the certificate file. i.e. #{cert_path}/certs/#{cert_file}
• key - The final path of the key file. i.e. #{cert_path}/private/#{key_file}
• chain - The final path of the chain file. i.e. #{cert_path}/certs/#{chain_file}

Readonly Attribute Example

# where node.fqdn = 'example.com'
tld = certificate_manage 'top_level_domain'
tld_cert_location = tld.certificate # => /etc/ssl/certs/example.com.pem

# where node.fqdn = 'sub.example.com'
sbd = certificate_manage 'sub_domain' do
  cert_path '/bobs/emporium'
  create_subfolders false
end
sbd_cert_location = sbd.key # => /bobs/emporium/sub.example.com.key

providers

• certificate_manage - The reusable LWRP to manage certificates, keys, and CA bundles

Usage

Here is a flushed out example using the LWRP to manage your certificate items on a Postfix bridgehead. The following example should select the mail data bag object, from the certificates data bag.

It should then place the managed certificate files in /etc/postfix/ssl, and change the owner/group to postfix.

certificate_manage "mail" do
  cert_path "/etc/postfix/ssl"
  owner "postfix"
  group "postfix"
end

Setting FQDN during the converge?

If you are updating the FQDN of the node during converge, be sure to use lazy attribute evaluation when using the LWRP to ensure node['fqdn'] refers to the updated value.

certificate_manage "wildcard" do
  cert_file lazy { "#{node['fqdn']}.pem" }
  key_file lazy { "#{node['fqdn']}.key" }
  chain_file lazy { "#{node['fqdn']}-bundle.crt" }
end

License and Author

Author:: Eric G. Wolfe eric.wolfe@gmail.com

Copyright:: 2012, Eric G. Wolfe

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.