[[pki-realm]] === PKI User Authentication You can configure {security} to use Public Key Infrastructure (PKI) certificates to authenticate users. This requires clients to present X.509 certificates. To use PKI, you configure a PKI realm, enable client authentication on the desired network layers (transport or http), and map the Distinguished Names (DNs) from the user certificates to {security} roles in the <>. You can also use a combination of PKI and username/password authentication. For example, you can enable SSL/TLS on the transport layer and define a PKI realm to require transport clients to authenticate with X.509 certificates, while still authenticating HTTP traffic using username and password credentials. You can also set `xpack.security.transport.ssl.client_authentication` to `optional` to allow clients without certificates to authenticate with other credentials. IMPORTANT: You must enable SSL/TLS and enabled client authentication to use PKI. For more information, see <>. ==== PKI Realm Configuration Like other realms, you configure options for a `pki` realm under the `xpack.security.authc.realms` namespace in `elasticsearch.yml`. To configure `pki` realm: . Add a realm configuration of type `pki` to `elasticsearch.yml` under the `xpack.security.authc.realms` namespace. At a minimum, you must set the realm `type` to `pki`. If you are configuring multiple realms, you should also explicitly set the `order` attribute. See <> for all of the options you can set for a `pki` realm. + For example, the following snippet shows the most basic `pki` realm configuration: + [source, yaml] ------------------------------------------------------------ xpack: security: authc: realms: pki1: type: pki ------------------------------------------------------------ + With this configuration, any certificate trusted by the SSL/TLS layer is accepted for authentication. The username is the common name (CN) extracted from the DN of the certificate. + IMPORTANT: When you configure realms in `elasticsearch.yml`, only the realms you specify are used for authentication. If you also want to use the `native` or `file` realms, you must include them in the realm chain. + If you want to use something other than the CN of the DN as the username, you can specify a regex to extract the desired username. For example, the regex in the following configuration extracts the email address from the DN: + [source, yaml] ------------------------------------------------------------ xpack: security: authc: realms: pki1: type: pki username_pattern: "EMAILADDRESS=(.*?)(?:,|$)" ------------------------------------------------------------ + . Restart Elasticsearch. [[pki-ssl-config]] ==== PKI and SSL Settings The PKI realm relies on the SSL settings of the node's network interface (transport or http). The realm can be configured to be more restrictive than the underlying network connection - that is, it is possible to configure the node such that some connections are accepted by the network interface but then fail to be authenticated by the PKI realm. However the reverse is not possible - the PKI realm cannot authenticate a connection that has been refused by the network interface. In particular this means: * The transport or http interface must request client certificates by setting `client_authentication` to `optional` or `required`. * The interface must _trust_ the certificate that is presented by the client by configuring either the `truststore` or `certificate_authorities` paths, or by setting `verification_mode` to `none`. * The _protocols_ supported by the interface must be compatible with those used by the client. The relevant network interface (transport or http) must be configured to trust any certificate that is to be used within the PKI realm. However it possible to configure the PKI realm to trust only a _subset_ of the certificates accepted by the network interface. This is useful when the SSL/TLS layer trusts clients with certificates that are signed by a different CA than the one that signs your users' certificates. To configure the PKI realm with its own truststore, specify the `truststore.path` option as below: [source, yaml] ------------------------------------------------------------ xpack: security: authc: realms: pki1: type: pki truststore: path: "/path/to/pki_truststore.jks" password: "x-pack-test-password" ------------------------------------------------------------ The `certificate_authorities` option may be used as an alternative to the `truststore.path` setting. [[pki-settings]] ===== PKI Realm Settings [cols="4,^3,10"] |======================= | Setting | Required | Description | `type` | yes | Indicates the realm type. Must be set to `pki`. | `order` | no | Indicates the priority of this realm within the realm chain. Realms with a lower order are consulted first. Although not required, we recommend explicitly setting this value when you configure multiple realms. Defaults to `Integer.MAX_VALUE`. | `enabled` | no | Indicates whether this realm is enabled or disabled. Enables you to disable a realm without removing its configuration. Defaults to `true`. | `username_pattern` | no | Specifies the regular expression pattern used to extract the username from the certificate DN. The first match group is used as the username. Defaults to `CN=(.*?)(?:,\|$)`. | `certificate_authorities` | no | List of paths to the PEM encoded certificate files that should be trusted. This setting may not be used with `truststore.path`. | `truststore.path` | no | The path to the truststore. Defaults to the path defined by {ref}/security-settings.html#ssl-tls-settings[SSL/TLS settings]. This setting may not be used with `certificate_authorities`. | `truststore.password` | no/yes | Specifies the password for the truststore. Must be provided if `truststore.path` is set. | `truststore.algorithm` | no | Specifies the algorithm used for the truststore. Defaults to `SunX509`. | `files.role_mapping` | no | Specifies the <> for the <>. Defaults to `CONFIG_DIR/x-pack/role_mapping.yml`. |======================= [[assigning-roles-pki]] ==== Mapping Roles for PKI Users You map roles for PKI users through the {ref}/security-api-role-mapping.html[role-mapping API], or by using a file stored on each node. When a user authenticates against a PKI realm, the privileges for that user are the union of all privileges defined by the roles to which the user is mapped. You identify a user by the distinguished name in their certificate. For example, the following mapping configuration maps `John Doe` to the `user` role: Using the role-mapping API: [source,js] -------------------------------------------------- PUT _xpack/security/role_mapping/users { "roles" : [ "user" ], "rules" : { "field" : { "dn" : "cn=John Doe,ou=example,o=com" <1> } }, "enabled": true } -------------------------------------------------- // CONSOLE <1> The distinguished name (DN) of a PKI user. Or, alternatively, configured in a role-mapping file: [source, yaml] ------------------------------------------------------------ user: <1> - "cn=John Doe,ou=example,o=com" <2> ------------------------------------------------------------ <1> The name of a role. <2> The distinguished name (DN) of a PKI user. The disinguished name for a PKI user follows X.500 naming conventions which place the most specific fields (like `cn` or `uid`) at the beginning of the name, and the most general fields (like `o` or `dc`) at the end of the name. Some tools, such as _openssl_, may print out the subject name in a different format. One way that you can determine the correct DN for a certificate is to use the {ref}/security-api-authenticate.html[authenticate API] (use the relevant PKI certificate as the means of authentication) and inspect the metadata field in the result. The user's distinguished name will be populated under the `pki_dn` key. You can also use the authenticate API to validate your role mapping. For more information, see <>.