Vault Authentication

Add authentication to a Service or Route with an access token and secret token. Credential tokens are stored securely via Vault. Credential lifecyles can be managed through the Kong Admin API, or independently via Vault.

Usage

In order to use the plugin, you first need to create a Consumer to associate one or more credentials to. The Consumer represents a developer using the upstream service. Additionally, a Vault object must be created to represent the connection Kong will use to communicate with a Vault server, where access and secret tokens will be stored.

Create a Consumer

You need to associate a credential to an existing [Consumer][consumer-object] object. To create a Consumer, you can execute the following request:

curl -X POST http://kong:8001/consumers/ \
  --data "username=<USERNAME>" \
  --data "custom_id=<CUSTOM_ID>"

Response:

HTTP/1.1 201 Created

{
    "username":"<USERNAME>",
    "custom_id": "<CUSTOM_ID>",
    "created_at": 1472604384000,
    "id": "7f853474-7b70-439d-ad59-2481a0a9a904"
}

A [Consumer][consumer-object] can have many credentials.

If you are also using the ACL plugin and allowed lists with this service, you must add the new consumer to an allowed group. See [ACL: Associating Consumers][acl-associating] for details.

Create a Vault

The Vault plugin supports HashiCorp Vault KV Secrets Engine versions 1 and 2.

A Vault object represents the connection between Kong and a Vault server. It defines the connection and authentication information used to communicate with the Vault API. This allows different instances of the vault-auth plugin to communicate with different Vault servers, providing a flexible deployment and consumption model.

Vault objects require setting a vault_token attribute. This attribute is referenceable, which means it can be securely stored as a secret in a vault. References must follow a specific format.

Vault objects can be created via the following HTTP request:

curl -X POST http://localhost:8001/vault-auth \
  --header 'Content-Type: multipart/form-data' \
  --form name=kong-auth \
  --form mount=kong-auth \
  --form protocol=http \
  --form host=127.0.0.1 \
  --form port=8200 \
  --form vault_token=<token> \
  --form kv=<secret_version>

HTTP/1.1 201 Created

{
  "host": "127.0.0.1",
  "created_at": 1605288799,
  "vault_token": "<token>",
  "mount": "kong-auth",
  "protocol": "http",
  "name": "kong-auth",
  "port": 8200,
  "updated_at": 1605288799,
  "id": "c22198a3-cf54-428b-bed2-59c1f3760823",
  "kv": "v2"
}

<secret_version> can be configured with the values v1 or v2, which correspond to KV secrets engines version 1 and 2 respectively. This assumes a Vault server is accessible via 127.0.0.1:8200, and that a version 1 or 2 KV secrets engine has been enabled at kong-auth. Vault KV secrets engine documentation is available via the Vault documentation for version 1 and version 2.

Create an Access/Secret Token Pair

vault-auth credentials are defined as a pair of tokens: an access token that identifies the owner of the credential, and a secret token that is used to authenticate ownership of the access token.

Token pairs can be managed either via the Kong Admin API, or independently via direct access with Vault. Token pairs must be associated with an existing Kong Consumer. Creating a token pair with the Kong Admin API can be done via the following request:

curl -X POST http://kong:8001/vault-auth/{vault}/credentials/{consumer}

Response:

HTTP/1.1 201 Created

{
    "data": {
        "access_token": "v3cOV1jWglS0PFOrTcdr85bs1GP0e2yM",
        "consumer": {
            "id": "64063284-e3b5-48e7-9bca-802251c32138"
        },
        "created_at": 1550538920,
        "secret_token": "11XYyybbu3Ty0Qt4ImIshPGQ0WsvjLzl",
        "ttl": null
    }
}

When the access_token or secret_token values are not provided, token values will be automatically generated via a cryptographically-secure random number generator (CSPRNG).

Integrating Vault objects with Vault-Auth plugins

Vault objects are treated as foreign references in plugin configs, creating a seamless lifecycle relationship between Vault instances and plugins with which they’re associated. vault-auth plugins require an association with a Vault object, which can be defined with the following HTTP request during plugin creation:

curl -X POST http://kong:8001/plugins \
  --data name=vault-auth \
  --data config.vault.id=<uuid>

Response:

HTTP/1.1 201 Created

{
  "created_at": 1550539002,
  "config": {
    "tokens_in_body": false,
    "secret_token_name": "secret_token",
    "run_on_preflight": true,
    "vault": {
      "id": "d3da058d-0acb-49c2-b7fe-72b3e9fd4b0a"
    },
    "anonymous": null,
    "hide_credentials": false,
    "access_token_name": "access_token"
  },
  "id": "b4d0cbb7-bff2-4599-ba19-67c705c15b9a",
  "service": null,
  "enabled": true,
  "run_on": "first",
  "consumer": null,
  "route": null,
  "name": "vault-auth"
}

Where <uuid> is the id of an existing Vault object.

Using Vault credentials

Simply make a request with the access_token and secret_token as querystring parameters:

curl http://kong:8000/{proxy path}?access_token=<access token>&secret_token=<secret token>

Or in a header:

curl http://kong:8000/{proxy path} \
  -H 'access_token: <access_token>' \
  -H 'secret_token: <secret_token>'

Deleting an Access/Secret Token Pair

Existing Vault credentials can be removed from the Vault server via the following API:

curl -X DELETE http://kong:8001/vault-auth/{vault}/credentials/token/{access token}

Response:

HTTP/1.1 204 No Content

Token TTL

When reading a token from Vault, Kong will search the responding KV value for the presence of a ttl field. When this is present, Kong will respect the advisory value of the ttlfield and store the value of the credential in cache for only as long as the ttl field defines. This allows tokens created directly in Vault, outside of the Kong Admin API, to be periodically refreshed by Kong.

Extra-Kong Token Pairs

Kong can read access/token secret pairs that have been created directly in Vault, outside of the Kong Admin API. Create Vault KV secret values must contain the following fields:

{
  access_token: <string>
  secret_token: <string>
  created_at: <integer>
  updated_at: <integer>
  ttl: <integer> (optional)
  consumer: {
    id: <uuid>
  }
}

Additional fields within the secret are ignored. The key must be the access_token value; this is the identifier by which Kong queries the Vault API to fetch the credential data. See the Vault documentation for version 1 or version 2 for further information on the KV secrets engine.

vault-auth token pairs can be created with the Vault HTTP API or the vault write command:

vault write kong-auth/foo - <<EOF
{
  "access_token": "foo",
  "secret_token": "supersecretvalue",
  "consumer": {
    "id": "ce67c25e-2168-4a09-81e5-e06187a2384f"
  },
  "ttl": 86400
}
EOF