Configuring a PKI realm
editConfiguring a PKI realm
editYou can configure Elasticsearch to use Public Key Infrastructure (PKI) certificates to authenticate users. This requires clients to present X.509 certificates.
You cannot use PKI certificates to authenticate users in Kibana.
To use PKI in Elasticsearch, 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 roles in the role-mapping API or role-mapping file.
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.
You must enable SSL/TLS and enable client authentication to use PKI.
For more information, see PKI user authentication.
-
Add a realm configuration for a
pki
realm toelasticsearch.yml
under thexpack.security.authc.realms.pki
namespace. If you are configuring multiple realms, you should explicitly set theorder
attribute. See PKI realm settings for all of the options you can set for apki
realm.For example, the following snippet shows the most basic
pki
realm configuration:xpack: security: authc: realms: pki: pki1: order: 1
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.
When you configure realms in
elasticsearch.yml
, only the realms you specify are used for authentication. If you also want to use thenative
orfile
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:
xpack: security: authc: realms: pki: pki1: username_pattern: "EMAILADDRESS=(.*?)(?:,|$)"
- Restart Elasticsearch.
- Enable SSL/TLS.
-
Enable client authentication on the desired network layers (transport or http).
The PKI realm relies on the TLS settings of the node’s network interface. 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
tooptional
orrequired
. -
The interface must trust the certificate that is presented by the client
by configuring either the
truststore
orcertificate_authorities
paths, or by settingverification_mode
tonone
. Seessl.verification_mode
for an explanation of this setting. - 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. For example:xpack: security: authc: realms: pki: pki1: truststore: path: "/path/to/pki_truststore.jks" password: "x-pack-test-password"
The
certificate_authorities
option can be used as an alternative to thetruststore.path
setting. -
The transport or http interface must request client certificates by setting
-
Map roles for PKI users.
You map roles for PKI users through the role mapping APIs 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 theuser
role:Using the role-mapping API:
PUT /_security/role_mapping/users { "roles" : [ "user" ], "rules" : { "field" : { "dn" : "cn=John Doe,ou=example,o=com" } }, "enabled": true }
Or, alternatively, configured in a role-mapping file:
The distinguished name for a PKI user follows X.500 naming conventions which place the most specific fields (like
cn
oruid
) at the beginning of the name, and the most general fields (likeo
ordc
) 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 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 Mapping users and groups to roles.
The PKI realm supports authorization realms as an alternative to role mapping.