The name is derived from "Fort Knox" the safest place to store valuables in history. At least that is the myth. This tool or set of utilities is explicitly for managing TLS certificates including metadata about them and storing it in a backend.
Primary components used are Python, Hashicorp Vault, Let's Encrypt and certbot.
Let’s Encrypt is a certificate authority managed by the Internet Security Research Group (ISRG). It utilizes the Automated Certificate Management Environment (ACME) to automatically deploy free SSL certificates that are trusted by nearly all major browsers. The certificate compatibility list can be found here. Lets Encrypt has revolutionized the distribution of certificates for public facing servers.
Hashicorp Vault is a tool for storing secrets. It has a PKI Secret Engine backend which allows to use it as a certificate authority in an internal public key infrastructure deployment. Until now, Vault is best suited for issuing private certificates.
Let's Encrypt and Hashicorp Vault are complementary in certificate management.
.. image:: deployment-3d.png
There may not necessarily be a container between Certbot or the Devops agent but the key is all access to manage the certs goes through a knox command. Once in place the cert can be accessed directly from Vault by deployment mechanisms with or without knox. Essentially its just a key value path to json. Knox just unifies how and what is stored and provides convenience methods for managing the certs.
To get started::
pip install knox
You can also install the in-development version with::
pip install git+ssh://git@github.com/8x8cloud/knox.git@develop
Or run it as a container::
docker run 8x8cloud/knox
See Dynaconf for how the configuration is read in. At its simplest just add environment variables into a .env file.
Knox will store the certificate body, in its entirety, along with metadata related to the details of the certificate. The data will be organized and retreived using a tree struction mimicking the DNS naming heirarchy.
Tree Structure::
certificates:
├── com
│ └── example
│ └── cloud
│ ├── acceptance
│ ├── production
│ └── staging
├── internal
│ └── example
└── net
└── example
As a result the host name www.example.com storage path will be /com/example/www
Additional data will be stored with the body of the certificates. A jinja template will be provided. Although the cert body and cert data will have alternate RBAC rules for accessing. Below is a sample::
{
"cert_info":
{
"subject": {
"commonName": "www.example.com",
"countryName": "US",
"emailAddress": "cert@example.com",
"localityName": "San Jose",
"organizationName": "Example, Inc.",
"organizationalUnitName": "Engineering",
"stateOrProvinceName": "CA"
},
"issuer": {
"commonName": "www.example.com",
"countryName": "US",
"emailAddress": "cert@example.com",
"localityName": "San Jose",
"organizationName": "Example, Inc.",
"organizationalUnitName": "Engineering",
"stateOrProvinceName": "CA"
},
"key_details": {
"fingerprint_sha256": "f6874a226e4d2ea54eed11d8d71e27f5fbd965630aa84f71414209b0227c448c",
"key": {
"size": 4096,
"type": "RSA"
},
"serial_number": "11672594923309745709",
"version": "v1"
},
"validity": {
"not_valid_after": "2021-05-17 18:49:00",
"not_valid_before": "2020-05-17 18:49:00"
}
},
"cert_body":
{
"private": "REDACTED",
"chain": "REDACTED",
"public": "REDACTED"
}
}
This project was initialized using a very cool python project templating tool called cookiecutter-pylibrary from Ionel Cristian Mărieș. Definitely check it out to see all the tools available and good usage docs.
Python setup on a Mac using pyenv::
# Pyenv for managing multiple versions of python
brew install pyenv
# Install all versions you want to test locally
pyenv install <version list>
# Enable the versions
pyenv local <version list>
To execute everything run::
tox
To see all the tox environments::
tox -l
To only build the docs::
tox -e docs
To build and verify that the built package is proper and other code QA checks::
tox -e check
To update Travis CI configuration::
tox -e bootstrap
You will need a Vault server running locally::
>docker run \
--cap-add=IPC_LOCK \
-p 8201:8201 \
-p 8200:8200 \
-e 'VAULT_DEV_ROOT_TOKEN_ID=knox' \
-d --name=dev-vault \
vault
>docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d89fbfd340c3 vault "docker-entrypoint.s…" 5 hours ago Up 5 hours 0.0.0.0:8200-8201->8200-8201/tcp dev-vault
Set the token ID and container name to your preferences. Verify you can talk to vault using the vault cli::
>export VAULT_ADDR=http://0.0.0.0:8200
>export VAULT_TOKEN=knox
>vault status
Key Value
--- -----
Seal Type shamir
Initialized true
Sealed false
Total Shares 1
Threshold 1
Version 1.4.1
Cluster Name vault-cluster-31da8ea9
Cluster ID 043bfc14-09b1-6033-1c3b-8aeace3adc60
HA Enabled false
Setup your local app role::
# Add the cert admin policy
>vault policy write cert_admin config/cert_admin-policy.hcl
Success! Uploaded policy: cert_admin
# Enable approle auth
>vault auth enable approle
Success! Enabled approle auth method at: approle/
# Create an app role
>vault write auth/approle/role/knox-admin \
bind_secret_id=true \
period=0 \
policies="cert_admin" \
token_num_uses=1 \
token_ttl=5m \
token_max_tll=30m \
secret_id_num_uses=0 \
secret_id_ttl=0 \
token_no_default_policy=true
Success! Data written to: auth/approle/role/knox-admin
# Read role-id
vault read auth/approle/role/knox-admin/role-id
export KNOX_VAULT_APPROLE=$(vault read -format=json auth/approle/role/knox-admin/role-id | jq -r '.data.role_id')
# generate secret-id
vault write -f auth/approle/role/knox-admin/secret-id
export KNOX_VAULT_SECRET_ID=$(vault write -f -format=json auth/approle/role/knox-admin/secret-id | jq -r '.data.secret_id')
Update your knox configuration using .env or direct environment variables::
ENVVAR_PREFIX_FOR_DYNACONF=KNOX
INCLUDES_FOR_DYNACONF='./config/*'
KNOX_TEMP=/tmp
KNOX_LOG_LEVEL=DEBUG
KNOX_STORE_ENGINE=vault
KNOX_VAULT_URL=http://127.0.0.1:8200
KNOX_VAULT_TOKEN="knox"
KNOX_VAULT_MOUNT="certificates"
KNOX_VAULT_CLIENT_MAX_VERSIONS=10
KNOX_VAULT_CLIENT_CAS=False
KNOX_FILE_HOME=./test
And Or use a settings file::
{
"default": {
"ENVVAR_PREFIX_FOR_DYNACONF": "KNOX",
"INCLUDES_FOR_DYNACONF": "./config/*",
"KNOX_TEMP": "./tmp",
"KNOX_LOG_LEVEL": "DEBUG",
"KNOX_STORE_ENGINE": "vault",
"KNOX_VAULT_URL": "http://127.0.0.1:8200",
"KNOX_VAULT_TOKEN": "knox",
"KNOX_VAULT_MOUNT": "certificates",
"KNOX_VAULT_CLIENT_MAX_VERSIONS": "10",
"KNOX_VAULT_CLIENT_CAS": "True",
"KNOX_FILE_HOME": "./test"
},
"development": {
"ENVVAR_PREFIX_FOR_DYNACONF": "KNOX",
"INCLUDES_FOR_DYNACONF": "./config/*"
},
"production": {
"ENVVAR_PREFIX_FOR_DYNACONF": "KNOX",
"INCLUDES_FOR_DYNACONF": "./config/*"
}
}
Generate some test self signed certificates::
# create a config file for openssl
[req]
distinguished_name = req_distinguished_name
x509_extensions = v3_req
prompt = no
[req_distinguished_name]
C = US
ST = VA
L = SomeCity
O = MyCompany
OU = MyDivision
CN = www.company.com
[v3_req]
keyUsage = keyEncipherment, dataEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
[alt_names]
DNS.1 = www.company.net
DNS.2 = company.com
DNS.3 = company.net
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 \
-keyout cert-key.pem \
-out cert-pub.pem \
-config san.cnf -extensions 'v3_req'
xtensions 'v3_req'
Generating a 2048 bit RSA private key
..................................+++
...........+++
writing new private key to 'cert-key.pem'
-----
Save a certificate to vault::
export VAULT_ADDR=http://localhost:8200
export KNOX_VAULT_URL=http://localhost:8200
export KNOX_VAULT_TOKEN=knox
export KNOX_VAULT_APPROLE=$(vault read -format=json auth/approle/role/knox-admin/role-id | jq -r '.data.role_id')
export KNOX_VAULT_SECRET_ID=$(vault write -f -format=json auth/approle/role/knox-admin/secret-id | jq -r '.data.secret_id')
knox cert --pub cert-pub.pem --key cert-key.pem save www.company.com
Search for stored certificates::
knox store find \* # list all the certificates info
knox store find www.company.com
knox store find *.example.com # list all the *.example.com certificates
knox store find com/example/www # list about www.example.com
Don't want to install python, I got you::
docker run --net=host 8x8cloud/knox --help
Usage: knox [OPTIONS] COMMAND [ARGS]...
Utilities for managing and storing TLS certificates using backing store
(Vault).
Options:
-l, --log [TRACE|DEBUG|INFO|SUCCESS|WARNING|ERROR|CRITICAL]
Sets the level of logging displayed
[default: INFO]
-v, --verbose Display log output to console
--version Show the version and exit.
--help Show this message and exit.
Commands:
cert Certificate utilities.
store Store commands.
If using docker mount a volume to get to your certs::
docker run --net=host \
-v ~/dev/knox/examples/:/examples \
8x8cloud/knox cert \
--pub /examples/sample_cert1.pem \
--key /examples/sample_key1.pem \
save www.example.com