Configuring step-ca

• bind to a non-default address
• generate ACME certificates
• adjust the default lifetime of certificates
• store certificates in memory, on the file system, or in a database
• set the root and intermediate PKI chain used to sign new certificates
• and much more

Overview

• Specify a Configuration File
• Environment Variables
• Basic Configuration Options
• Provisioners
• Certificate Issuance Policies
• Certificate Templates
• Databases
  • Badger
  • BoltDB
  • MySQL
  • PostgreSQL
  • Schema

Specify a Configuration File

$ step-ca $(step path)/config/ca.json

Environment Variables

• STEPDEBUG When set to 1, step-ca provides extra diagnostic information for debugging. This variable can also be used with step.

Basic Configuration Options

Example Configuration

{
  "root": "examples/pki/secrets/root_ca.crt",
  "federatedRoots": ["examples/pki/secrets/federated_root_ca.crt"],
  "crt": "examples/pki/secrets/intermediate_ca.crt",
  "key": "examples/pki/secrets/intermediate_ca_key",
  "address": ":9000",
  "dnsNames": [
    "localhost"
  ],
  "logger": {
    "format": "text"
  },
  "ssh": {
    "hostKey": "/examples/pki/secrets/secrets.host.key",
    "userKey": "/examples/pki/secrets/secrets.user.key"
  },
  "db": {
    "type": "badgerv2",
    "dataSource": "/Users/carl/.step/authorities/config-example/db"
  }, 
  "crl": {
    "enabled": false
  }, 
  "authority": {
    "claims": {
      "minTLSCertDuration": "5m",
      "maxTLSCertDuration": "24h",
      "defaultTLSCertDuration": "24h",
      "disableRenewal": false,
      "allowRenewalAfterExpiry": false,
      "minHostSSHCertDuration": "5m",
      "maxHostSSHCertDuration": "1680h",
      "defaultHostSSHCertDuration": "720h",
      "minUserSSHCertDuration": "5m",
      "maxUserSSHCertDuration": "24h",
      "defaultUserSSHCertDuration": "16h"
    },
    "policy": {
      "x509": {
        "allow": {
          "dns": ["*.local"]
        }
      },
      "ssh": {
        "user": {
          "allow": {
            "email": ["@local"]
          }
        },
        "host": {
          "allow": {
            "dns": ["*.local"]
          }
        }
      }
    },
    "provisioners": [
      {
        "type": "jwk",
        "name": "mike@smallstep.com",
        "key": {
          "use": "sig",
          "kty": "EC",
          "kid": "YYNxZ0rq0WsT2MlqLCWvgme3jszkmt99KjoGEJJwAKs",
          "crv": "P-256",
          "alg": "ES256",
          "x": "LsI8nHBflc-mrCbRqhl8d3hSl5sYuSM1AbXBmRfznyg",
          "y": "F99LoOvi7z-ZkumsgoHIhodP8q9brXe4bhF3szK-c_w"
        },
        "encryptedKey": "eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJjdHkiOiJqd2sranNvbiIsImVuYyI6IkEyNTZHQ00iLCJwMmMiOjEwMDAwMCwicDJzIjoiVERQS2dzcEItTUR4ZDJxTGo0VlpwdyJ9.2_j0cZgTm2eFkZ-hrtr1hBIvLxN0w3TZhbX0Jrrq7vBMaywhgFcGTA.mCasZCbZJ-JT7vjA.bW052WDKSf_ueEXq1dyxLq0n3qXWRO-LXr7OzBLdUKWKSBGQrzqS5KJWqdUCPoMIHTqpwYvm-iD6uFlcxKBYxnsAG_hoq_V3icvvwNQQSd_q7Thxr2_KtPIDJWNuX1t5qXp11hkgb-8d5HO93CmN7xNDG89pzSUepT6RYXOZ483mP5fre9qzkfnrjx3oPROCnf3SnIVUvqk7fwfXuniNsg3NrNqncHYUQNReiq3e9I1R60w0ZQTvIReY7-zfiq7iPgVqmu5I7XGgFK4iBv0L7UOEora65b4hRWeLxg5t7OCfUqrS9yxAk8FdjFb9sEfjopWViPRepB0dYPH8dVI.fb6-7XWqp0j6CR9Li0NI-Q",
        "claims": {
          "minTLSCertDuration": "1m0s",
          "defaultTLSCertDuration": "2m0s"
        },
        "options": {
          "x509": {
            "templateFile": "templates/certs/x509/default.tpl"
          },
          "ssh": {
            "templateFile": "templates/certs/ssh/default.tpl"
          }
        }
      },
      {
        "type": "OIDC",
        "name": "Google",
        "clientID": "1087160488420-8qt7bavg3qesdhs6it824mhnfgcfe8il.apps.googleusercontent.com",
        "clientSecret": "udTrOT3gzrO7W9fDPgZQLfYJ",
        "configurationEndpoint": "https://accounts.google.com/.well-known/openid-configuration",
        "admins": ["you@smallstep.com"],
        "domains": ["smallstep.com"],
        "listenAddress": ":10000",
        "claims": {
          "maxTLSCertDuration": "8h",
          "defaultTLSCertDuration": "2h",
          "enableSSHCA": true,
          "disableRenewal": true
        },
        "options": {
          "x509": {
            "templateFile": "templates/certs/x509/default.tpl"
          },
          "ssh": {
            "templateFile": "templates/certs/ssh/default.tpl"
          }
        }
      },
      {
        "type": "SSHPOP",
        "name": "sshpop-smallstep",
        "claims": {
          "enableSSHCA": true
        }
      },
      {
        "type": "ACME",
        "name": "my-acme-provisioner"
      }
    ]
  },
  "tls": {
    "cipherSuites": [
      "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
      "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256"
    ],
    "minVersion": 1.2,
    "maxVersion": 1.3,
    "renegotiation": false
  },
  "password": "p@55w0rd"
}

Configuration Options

• root: location of the root certificate PEM file on the filesystem. The root certificate is used to mutually authenticate all API clients of the CA. This can be a string containing one root PEM file, or an array containing multiple root CA files (useful for root rotation).

• federatedRoots: location of the federated root certificates on the filesystem. The federated roots are used to authenticate client and servers using TLS certificates from multiple CAs.

• crt: location of the intermediate certificate on the filesystem. The intermediate certificate is returned alongside each new certificate, allowing the client to complete the certificate chain. Multiple intermediates are allowed here. When multiple intermediates are supplied, the first certificate in the PEM bundle must be the one used for signing.

• key: location of the intermediate private key on the filesystem. The intermediate key signs all new certificates generated by the CA.

• kms: enables and configures cryptographic protection using cloud key management services or hardware security modules. See Cryptographic Protection.

  • type: required. one of azurekms, awskms, cloudkms, pkcs11, or yubikey

  • uri: this field can be used to specify other fields in this section, and its value takes precedence over those values. See cryptographic protection for examples.

  • region: for awskms, the AWS region

  • profile: for awskms, the AWS profile

  • credentialsFile: for cloudkms, the path to a Google Cloud Platform credentials JSON file for a role that can access cloudkms

  • pin: for yubikey, the PIN of the YubiKey PIV application

• address: ex. 127.0.0.1:8080 - address and port on which the CA bind and respond to requests.

• dnsNames: comma separated list of DNS name(s) for the CA.

• logger: the default logging format for the CA is text. The other option is json.

• ssh: enables the provisioning of SSH certificates by the CA. Add this section to an existing ca.json to enable SSH for an existing CA. SSH keys can be created by running step crypto keypair host.pub host.key and step crypto keypair user.pub user.key.

  • userKey: the signing key for user SSH certificates.

  • hostKey: the signing key for host SSH certificates.

• db: data persistence layer. See databases, below.

• crl: Certificate Revocation List (CRL) settings. (experimental)

  • enabled: enables CRL generation (true to generate, false to disable). Default is false.

  • generateOnRevoke: a revoke will generate a new CRL if the crl is enabled. Default is false.

  • cacheDuration: the duration until next update of the CRL. Defaults to 24h.

  • renewPeriod: the time between CRL regeneration. Defaults to ~2/3 of the cacheDuration.

• tls: settings for negotiating communication with the CA; includes acceptable ciphersuites, min/max TLS version, etc.

• authority: controls the request authorization and signature processes.

  • type: the type of backing CA service that issues certificates for this step-ca instance. The default is an internal certificate authority service. Other options can turn step-ca into a Registration Authority: stepcas uses a remote step-ca instance as the backend, cloudcas uses Google CloudCAS, vaultcas uses Hashicorp Vault.

  • template: default ASN1DN values for new certificates. See Templates.

  • claims: default validation for requested attributes in the certificate request. Can be overridden by similar claims objects defined by individual provisioners.

    • minTLSCertDuration: do not allow certificates with a duration less than this value.

    • maxTLSCertDuration: do not allow certificates with a duration greater than this value.

    • defaultTLSCertDuration: if no certificate validity period is specified, use this value.

    • disableRenewal: do not allow any certificates to be renewed. The default is false.

    • allowRenewalAfterExpiry: ☠️ allow expired certificates to be renewed. The default is false. This option adds security risk; proceed with caution and consider alternatives.

    • minUserSSHCertDuration: do not allow certificates with a duration less than this value.

    • maxUserSSHCertDuration: do not allow certificates with a duration greater than this value.

    • defaultUserSSHCertDuration: if no certificate validity period is specified, use this value.

    • minHostSSHCertDuration: do not allow certificates with a duration less than this value.

    • maxHostSSHCertDuration: do not allow certificates with a duration greater than this value.

    • defaultHostSSHCertDuration: if no certificate validity period is specified, use this value.

    • enableSSHCA: enable this provisioner to generate SSH Certificates. The default value is false.

    • disableIssuedAtCheck: ☠️ disable a check verifying that provisioning tokens must be issued after the CA has booted. This claim is one prevention against token reuse. The default value is false. Do not change this unless you know what you are doing.

  • provisioners: list of certificate Provisioners. Each provisioner has a name, associated authentication attributes, and an optional claims attribute that overrides any values set in the global claims directly underneath authority. The step ca provisioner command group can add, modify, and remove provisioners. See Provisioners.

    • claims: Each provisioner can override the authority-wide claims settings. See the authority's claims section above for a complete list of options.

    • options: This optional attribute allows an operator to set templates applied to all X.509 or SSH certificates generated using the provisioner. See Templates.

  • password: ☠️ plain text password for starting the CA. Used to decrypt the intermediate CA private key.

    In production, do not store a plain text password in your ca.json. Use the --password-file flag when running step-ca. This attribute is a convenience that should be avoided in production.

Provisioners

Policy

• A dns rule for www.example.com, only matching the domain www.example.com
• A dns rule for *.internal.example.com, matching all subdomains of internal.example.com.
• An ip rule for the 192.168.0.0/24 CIDR, matching all IPs in the range from 192.168.0.0-192.168.0.255.
• An email rule for @devops, matching all SSH user principals in the @devops domain.
• A uri rule for *.example.com, matching all URIs for subdomains of example.com, ignoring the URI scheme, path, query and fragment parts.

Templates

• Custom SANs or extensions for X.509 certificates
• Create longer certificate chains, including multiple intermediate CAs
• Embed SSH force-command or source-address extensions
• Evaluate basic logic operations on certificate's parameters, and fail if requirements are not met

Databases

• Issued certificates and certificate metadata, to facilitate passive revocation
• ACME accounts
• Used one-time-use tokens

• Badger
• BoltDB
• MySQL
• PostgreSQL

Badger

{
  ...
  "db": {
    "type": "badger",
    "dataSource": "./.step/db",
    "valueDir": "./.step/valuedb",
    "badgerFileLoadingMode": "MemoryMap"
  },
  ...
},

• type

  • badger: currently refers to Badger V1. This is subject to change.
  • badgerV1: explicitly select Badger V1.
  • badgerV2: explicitly select Badger V2.

• dataSource: path, database directory.

• valueDir [optional]: path, value directory, only if different from dataSource.

• badgerFileLoadingMode [optional]: can be set to FileIO (instead of the default MemoryMap) to avoid memory-mapping log files. This can be useful in environments with low RAM. Make sure to use badgerV2 as the database type if using this option.

  • MemoryMap: default.
  • FileIO: This can be useful in environments with low RAM.

BoltDB

{
  ...
  "db": {
    "type": "bbolt",
    "dataSource": "./stepdb"
  },
  ...
}

• type: bbolt
• dataSource: path, database directory.

MySQL

{
  ...
  "db": {
    "type": "mysql",
    "dataSource": "user:password@tcp(127.0.0.1:3306)/",
    "database": "myDBName"
  },
  ...
},

• type: mysql
• dataSource: path, database directory.

PostgreSQL

{
  ...
  "db": {
    "type": "postgresql",
    "dataSource": "postgresql://user:password@127.0.0.1:5432/",
    "database": "myDBName"
  },
  ...
},

Options

• type: postgresql
• dataSource: a PostgreSQL DSN.
• database: database name. Takes precedence over name in the DSN if provided.

Use TLS with PostgreSQL

{
  ...
  "db": {
    "type": "postgresql",
    "dataSource": "postgresql://user:password@127.0.0.1:5432/dbname?sslmode=verify-full"
  },
  ...
},

{
  ...
  "db": {
    "type": "postgresql",
    "dataSource": "postgresql://user:password@127.0.0.1:5432/dbname?sslmode=verify-full&sslrootcert=/path/to/roots.pem&sslcert=/path/to/client.pem&sslkey=/path/to/client.key"
  },
  ...
},

Schema

Exporting Data