ClickHouse/tests/testflows/kerberos/requirements/requirements.md

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QA-SRS016 ClickHouse Kerberos Authentication

Software Requirements Specification

Table of Contents

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Introduction

This document specifies the behavior for authenticating existing users via Kerberos authentication protocol. Existing ClickHouse users, that are properly configured, have an ability to authenticate using Kerberos. Kerberos authentication is only supported for HTTP requests, and users configured to authenticate via Kerberos cannot be authenticated by any other means of authentication.

In order to use Kerberos authentication, Kerberos needs to be properly configured in the environment: Kerberos server must be present and user's and server's credentials must be set up. Configuring the Kerberos environment is outside the scope of this document.

Terminology

  • Principal - A unique identity that uses Kerberos.

  • Realm - A logical group of resources and identities that use Kerberos.

  • Ticket - An encrypted block of data that authenticates principal.

  • Credentials - A Kerberos ticket and a session key.

  • Kerberized request - A HTTP query to ClickHouse server, which uses GSS SPNEGO and Kerberos to authenticate client.

  • Unkerberized request - A HTTP query to ClickHouse server, which uses any other mean of authentication than GSS SPNEGO or Kerberos.

For a more detailed descriprion, visit Kerberos terminology.

Requirements

Generic

RQ.SRS-016.Kerberos

version: 1.0

ClickHouse SHALL support user authentication using Kerberos server.

Configuration

RQ.SRS-016.Kerberos.Configuration.MultipleAuthMethods

version: 1.0

ClickHouse SHALL generate an exception and TERMINATE in case some user in users.xml has a <kerberos> section specified alongside with any other authentication method's section, e.g. ldap, password.

RQ.SRS-016.Kerberos.Configuration.KerberosNotEnabled

version: 1.0

ClickHouse SHALL reject Kerberos authentication in case user is properly configured for using Kerberos, but Kerberos itself is not enabled in config.xml. For example:

<yandex>
    <!- ... -->
    <kerberos />
</yandex>
<yandex>
    <!- ... -->
    <kerberos>
        <principal>HTTP/clickhouse.example.com@EXAMPLE.COM</principal>
    </kerberos>
</yandex>
<yandex>
    <!- ... -->
    <kerberos>
        <realm>EXAMPLE.COM</realm>
    </kerberos>
</yandex>

RQ.SRS-016.Kerberos.Configuration.MultipleKerberosSections

version: 1.0

ClickHouse SHALL disable Kerberos and reject Kerberos authentication in case multiple kerberos sections are present in config.xml.

RQ.SRS-016.Kerberos.Configuration.WrongUserRealm

version: 1.0

ClickHouse SHALL reject Kerberos authentication if user's realm specified in users.xml doesn't match the realm of the principal trying to authenticate.

RQ.SRS-016.Kerberos.Configuration.PrincipalAndRealmSpecified

version: 1.0

ClickHouse SHALL generate an exception and disable Kerberos in case both realm and principal sections are defined in config.xml.

RQ.SRS-016.Kerberos.Configuration.MultiplePrincipalSections

version: 1.0

ClickHouse SHALL generate an exception and disable Kerberos in case multiple principal sections are specified inside kerberos section in config.xml.

RQ.SRS-016.Kerberos.Configuration.MultipleRealmSections

version: 1.0

ClickHouse SHALL generate an exception and disable Kerberos in case multiple realm sections are specified inside kerberos section in config.xml.

Valid User

RQ.SRS-016.Kerberos.ValidUser.XMLConfiguredUser

version: 1.0

ClickHouse SHALL accept Kerberos authentication for a user that is configured in users.xml and has Kerberos enabled, i.e.:

<yandex>
    <!- ... -->
    <users>
        <!- ... -->
        <my_user>
            <!- ... -->
            <kerberos>
                <realm>EXAMPLE.COM</realm>
            </kerberos>
        </my_user>
    </users>
</yandex>

RQ.SRS-016.Kerberos.ValidUser.RBACConfiguredUser

version: 1.0

ClickHouse SHALL accept Kerberos authentication if user is configured to authenticate via Kerberos using SQL queries

CREATE USER my_user IDENTIFIED WITH kerberos REALM 'EXAMPLE.COM'

or

CREATE USER my_user IDENTIFIED WITH kerberos

RQ.SRS-016.Kerberos.ValidUser.KerberosNotConfigured

version: 1.0

ClickHouse SHALL reject Kerberos authentication if username is valid but ClickHouse user is not configured to be authenticated using Kerberos.

Invalid User

RQ.SRS-016.Kerberos.InvalidUser

version: 1.0

ClickHouse SHALL reject Kerberos authentication if name of the principal attempting to authenticate does not translate to a valid ClickHouse username configured in users.xml or via SQL workflow.

RQ.SRS-016.Kerberos.InvalidUser.UserDeleted

version: 1.0

ClickHouse SHALL reject Kerberos authentication if ClickHouse user was removed from the database using an SQL query.

Kerberos Not Available

RQ.SRS-016.Kerberos.KerberosNotAvailable.InvalidServerTicket

version: 1.0

ClickHouse SHALL reject Kerberos authentication if ClickHouse user is configured to be authenticated using Kerberos and Kerberos server is unavailable, but ClickHouse doesn't have a valid Kerberos ticket or the ticket is expired.

RQ.SRS-016.Kerberos.KerberosNotAvailable.InvalidClientTicket

version: 1.0

ClickHouse SHALL reject Kerberos authentication if ClickHouse user is configured to to be authenticated using Kerberos and Kerberos server is unavailable, but the client doesn't have a valid Kerberos ticket or the ticket is expired.

RQ.SRS-016.Kerberos.KerberosNotAvailable.ValidTickets

version: 1.0

ClickHouse SHALL accept Kerberos authentication if no Kerberos server is reachable, but ClickHouse is configured to use valid credentials and ClickHouse has already processed some valid kerberized request (so it was granted a ticket), and the client has a valid ticket as well.

Kerberos Restarted

RQ.SRS-016.Kerberos.KerberosServerRestarted

version: 1.0

ClickHouse SHALL accept Kerberos authentication if Kerberos server was restarted.

Performance

RQ.SRS-016.Kerberos.Performance

version: 1.0

ClickHouse's performance for Kerberos authentication SHALL be comparable to regular authentication.

Parallel Requests processing

RQ.SRS-016.Kerberos.Parallel

version: 1.0

ClickHouse SHALL support parallel authentication using Kerberos.

RQ.SRS-016.Kerberos.Parallel.ValidRequests.KerberosAndNonKerberos

version: 1.0

ClickHouse SHALL support processing of simultaneous kerberized (for users configured to authenticate via Kerberos) and non-kerberized (for users configured to authenticate with any other means) requests.

RQ.SRS-016.Kerberos.Parallel.ValidRequests.SameCredentials

version: 1.0

ClickHouse SHALL support processing of simultaneously sent Kerberos requests under the same credentials.

RQ.SRS-016.Kerberos.Parallel.ValidRequests.DifferentCredentials

version: 1.0

ClickHouse SHALL support processing of simultaneously sent Kerberos requests under different credentials.

RQ.SRS-016.Kerberos.Parallel.ValidInvalid

version: 1.0

ClickHouse SHALL support parallel authentication of users using Kerberos server, some of which are valid and some invalid. Valid users' authentication should not be affected by invalid users' attempts.

RQ.SRS-016.Kerberos.Parallel.Deletion

version: 1.0

ClickHouse SHALL not crash when two or more Kerberos users are simultaneously deleting one another.

References