274 lines
11 KiB
Plaintext
274 lines
11 KiB
Plaintext
[[pki-realm-for-direct-clients]]
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==== PKI authentication for clients connecting directly to {es}
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To use PKI in {es}, you configure a PKI realm, enable client authentication on
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the desired network layers (transport or http), and map the Distinguished Names
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(DNs) from the Subject field in the user certificates to roles. You create the
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mappings in a role mapping file or use the role mappings API.
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If you want the same users to also be authenticated using certificates when they
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connect to {kib}, you must configure the {es} PKI realm to
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<<pki-realm-for-proxied-clients,allow delegation>> and to
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{kibana-ref}/kibana-authentication.html#pki-authentication[enable PKI authentication in {kib}].
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You can also use a combination of PKI and username/password authentication. For
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example, you can enable SSL/TLS on the transport layer and define a PKI realm to
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require transport clients to authenticate with X.509 certificates, while still
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authenticating HTTP traffic using username and password credentials. You can
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also set `xpack.security.transport.ssl.client_authentication` to `optional` to
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allow clients without certificates to authenticate with other credentials.
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IMPORTANT: You must enable SSL/TLS with client authentication to use PKI when
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clients connect directly to {es}.
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. Add a realm configuration for a `pki` realm to `elasticsearch.yml` under the
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`xpack.security.authc.realms.pki` namespace.
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If you are configuring multiple realms, you should
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explicitly set the `order` attribute. See <<ref-pki-settings>> for all of the
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options you can set for a `pki` realm.
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+
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--
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For example, the following snippet shows the most basic `pki` realm configuration:
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[source, yaml]
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------------------------------------------------------------
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xpack:
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security:
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authc:
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realms:
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pki:
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pki1:
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order: 1
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------------------------------------------------------------
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With this configuration, any certificate trusted by the {es} SSL/TLS layer is
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accepted for authentication. The username is the common name (CN) extracted
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from the DN in the Subject field of the end-entity certificate. This
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configuration does not permit PKI authentication to {kib}.
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IMPORTANT: When you configure realms in `elasticsearch.yml`, only the
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realms you specify are used for authentication. If you also want to use the
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`native` or `file` realms, you must include them in the realm chain.
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If you want to use something other than the CN of the Subject DN as the
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username, you can specify a regex to extract the desired username. The regex is
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applied on the Subject DN. For example, the regex in the following
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configuration extracts the email address from the Subject DN:
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[source, yaml]
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------------------------------------------------------------
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xpack:
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security:
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authc:
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realms:
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pki:
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pki1:
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username_pattern: "EMAILADDRESS=(.*?)(?:,|$)"
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------------------------------------------------------------
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NOTE: If the regex is too restrictive and does not match the Subject DN of the
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client's certificate, then the realm does not authenticate the certificate.
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--
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. Restart {es} because realm configuration is not reloaded automatically. If
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you're following through with the next steps, you might wish to hold the
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restart for last.
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. <<configuring-tls,Enable SSL/TLS>>.
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. Enable client authentication on the desired network layers (transport or http).
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+
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--
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When clients connect directly to {es} and are not proxy-authenticated, the PKI
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realm relies on the TLS settings of the node's network interface. The realm can
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be configured to be more restrictive than the underlying network connection.
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That is, it is possible to configure the node such that some connections
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are accepted by the network interface but then fail to be authenticated by the
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PKI realm. However, the reverse is not possible. The PKI realm cannot
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authenticate a connection that has been refused by the network interface.
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In particular this means:
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* The transport or http interface must request client certificates by setting
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`client_authentication` to `optional` or `required`.
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* The interface must _trust_ the certificate that is presented by the client
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by configuring either the `truststore` or `certificate_authorities` paths,
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or by setting `verification_mode` to `none`. See
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<<ssl-tls-settings,`ssl.verification_mode`>> for an explanation of this
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setting.
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* The _protocols_ supported by the interface must be compatible with those
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used by the client.
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The relevant network interface (transport or http) must be configured to trust
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any certificate that is to be used within the PKI realm. However, it is possible to
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configure the PKI realm to trust only a _subset_ of the certificates accepted
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by the network interface. This is useful when the SSL/TLS layer trusts clients
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with certificates that are signed by a different CA than the one that signs your
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users' certificates.
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To configure the PKI realm with its own truststore, specify the
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`truststore.path` option. The path must be located within the Elasticsearch
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configuration directory (ES_PATH_CONF). For example:
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[source, yaml]
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------------------------------------------------------------
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xpack:
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security:
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authc:
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realms:
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pki:
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pki1:
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truststore:
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path: "pki1_truststore.jks"
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------------------------------------------------------------
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If the truststore is password protected, the password should be configured by
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adding the appropriate `secure_password` setting to the {es} keystore. For
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example, the following command adds the password for the example realm above:
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[source, shell]
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------------------------------------------------------------
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bin/elasticsearch-keystore add \
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xpack.security.authc.realms.pki.pki1.truststore.secure_password
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------------------------------------------------------------
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The `certificate_authorities` option can be used as an alternative to the
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`truststore.path` setting, when the certificate files are PEM formatted
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. The setting accepts a list. The two options are exclusive, they cannot be both used
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simultaneously.
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--
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. Map roles for PKI users.
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+
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--
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You map roles for PKI users through the <<security-role-mapping-apis,role
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mapping APIs>> or by using a file stored on each node. Both configuration
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options are merged together. When a user authenticates against a PKI realm, the
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privileges for that user are the union of all privileges defined by the roles
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to which the user is mapped.
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You identify a user by the distinguished name in their certificate.
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For example, the following mapping configuration maps `John Doe` to the
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`user` role:
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Using the role-mapping API:
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[source,console]
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--------------------------------------------------
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PUT /_security/role_mapping/users
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{
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"roles" : [ "user" ],
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"rules" : { "field" : {
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"dn" : "cn=John Doe,ou=example,o=com" <1>
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} },
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"enabled": true
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}
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--------------------------------------------------
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<1> The distinguished name (DN) of a PKI user.
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Or, alternatively, configured inside a role-mapping file. The file's path
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defaults to `ES_PATH_CONF/role_mapping.yml`. You can specify a different path (which must be within
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ES_PATH_CONF) by using the `files.role_mapping` realm setting (e.g.
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`xpack.security.authc.realms.pki.pki1.files.role_mapping`):
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[source, yaml]
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------------------------------------------------------------
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user: <1>
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- "cn=John Doe,ou=example,o=com" <2>
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------------------------------------------------------------
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<1> The name of a role.
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<2> The distinguished name (DN) of a PKI user.
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The distinguished name for a PKI user follows X.500 naming conventions which
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place the most specific fields (like `cn` or `uid`) at the beginning of the
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name, and the most general fields (like `o` or `dc`) at the end of the name.
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Some tools, such as _openssl_, may print out the subject name in a different
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format.
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One way that you can determine the correct DN for a certificate is to use the
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<<security-api-authenticate,authenticate API>> (use the relevant PKI
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certificate as the means of authentication) and inspect the metadata field in
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the result. The user's distinguished name will be populated under the `pki_dn`
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key. You can also use the authenticate API to validate your role mapping.
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For more information, see <<mapping-roles>>.
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NOTE: The PKI realm supports <<authorization_realms,authorization realms>> as an
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alternative to role mapping.
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--
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[[pki-realm-for-proxied-clients]]
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==== PKI authentication for clients connecting to {kib}
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By default, the PKI realm relies on the node's network interface to perform the
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SSL/TLS handshake and extract the client certificate. This behaviour requires
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that that clients connect directly to {es} so that their SSL connection is
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terminated by the {es} node. If SSL/TLS authenticatication is to be performed
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by {kib}, the PKI realm must be configured to permit delegation.
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Specifically, when clients presenting X.509 certificates connect to {kib},
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{kib} performs the SSL/TLS authentication. {kib} then forwards the client's
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certificate chain, by calling an {es} API, to have them further validated by
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the PKI realms that have been configured for delegation.
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To permit authentication delegation for a specific {es} PKI realm, start by
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configuring the realm for the usual case, as detailed in the
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<<pki-realm-for-direct-clients>>
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section. Note that you must explicitly configure a `truststore` (or,
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equivalently `certificate_authorities`) even though it is the same trust
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configuration that you have configured on the network layer. Afterwards,
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simply toggle the `delegation.enabled` realm setting to `true`. This realm is
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now allowed to validate delegated PKI authentication (after restarting {es}).
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NOTE: PKI authentication delegation requires that the
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`xpack.security.authc.token.enabled` setting be `true` and that SSL/TLS be
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configured (without SSL/TLS client authentication).
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NOTE: {kib} also needs to be
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{kibana-ref}/kibana-authentication.html#pki-authentication[configured to allow
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PKI certificate authentication].
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A PKI realm with `delegation.enabled` still works unchanged for clients
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connecting directly to {es}. Directly authenticated users, and users that are PKI
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authenticated by delegation to {kib} both follow the same
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<<mapping-roles,role mapping rules>> or
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<<authorization_realms,authorization realms configurations>>.
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However, if you use the <<security-role-mapping-apis,role mapping APIs>>,
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you can distinguish between users that are authenticated by delegation and
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users that are authenticated directly. The former have the
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extra fields `pki_delegated_by_user` and `pki_delegated_by_realm` in the user's
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metadata. In the common setup, where authentication is delegated to {kib}, the
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values of these fields are `kibana` and `reserved`, respectively. For example,
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the following role mapping rule will assign the `role_for_pki1_direct` role to
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all users that have been authenticated directly by the `pki1` realm, by
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connecting to {es} instead of going through {kib}:
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[source,console]
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--------------------------------------------------
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PUT /_security/role_mapping/direct_pki_only
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{
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"roles" : [ "role_for_pki1_direct" ],
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"rules" : {
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"all": [
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{
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"field": {"realm.name": "pki1"}
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},
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{
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"field": {
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"metadata.pki_delegated_by_user": null <1>
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}
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}
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]
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},
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"enabled": true
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}
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--------------------------------------------------
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<1> only when this metadata field is set (it is *not* `null`) the user has been
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authenticated in the delegation scenario.
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