|Oracle® Fusion Middleware Administrator's Guide for Oracle Unified Directory
11g Release 2 (11.1.2)
Part Number E22648-05
|PDF · Mobi · ePub|
Most LDAP directory servers typically have a single superuser, which is much like the root account in traditional UNIX systems. This account can bypass access controls and other restrictions that might be enforced for regular users. In Oracle Unified Directory you can define multiple root users, and a privilege subsystem that makes it possible to control capabilities at a more fine-grained level.
The following sections describe root user accounts and the privilege subsystem:
Root user accounts are defined below the
cn=Root DNs,cn=config branch in the server configuration. Each root account is defined as a regular user entry, with the exception that it includes the
ds-cfg-root-dn-user auxiliary object class. A root user entry can also have one or more values for the
ds-cfg-alternate-bind-dn attribute. This attribute specifies alternate DNs that can be used to authenticate as that user (for example, so you can bind as
cn=Directory Manager instead of having to use
cn=Directory Manager,cn=Root DNs,cn=config, which is the actual entry DN).
The ability to define multiple root users, each in its own entry, has a number of advantages:
Each administrator that needs root access to the directory server can have their own account with their own credentials. This makes it easier to keep an audit trail of who does what in the directory server than if all of the administrators shared a single root account.
Because each root user account has its own set of credentials, the credentials for one root user can be changed without impacting any of the other root users. It is not necessary to coordinate root password changes among all of the administrators because each of them has their own account. If an administrator leaves, that account can simply be deactivated or removed.
Because each root user has its own entry, and you can put whatever attributes and object classes you want into that entry (as long as it also has the
ds-cfg-root-dn-user auxiliary object class), root users are capable of using strong authentication like the EXTERNAL or GSSAPI SASL mechanisms.
Root users are subject to password policy enforcement. This means that you can force root users to change their passwords on a regular basis, ensure that they are only allowed to authenticate or change their passwords using secure mechanisms, and ensure that they choose strong passwords. You can also use custom password policies for root users, so that they are subject to different sets of password policy requirements than other users in the directory.
You can define different resource limits for root users than for regular users. Because each root account has its own entry, operational attributes like
ds-rlim-lookthrough-limit work for root users just as they do with regular user accounts.
As mentioned above, root user accounts in traditional directories are special because they can bypass access controls and other restrictions, and there are some kinds of operations that only root users can perform. This is much like the concept of root users in traditional UNIX operating systems. However, there might be cases in which a regular user needs to do something that only a root user can do. If users are given root access, they are given far more power than they actually need to do their job, and system administrators have to hope that they use this power responsibly and do not intentionally or unintentionally impact some other part of the system. Alternately, the user might not be given root access and either not be able to perform a vital function or have to rely on one of the system administrators to perform the task.
Solaris 10 and onward address this problem in UNIX systems by creating a privilege subsystem (also called "process rights management"). The engineers developing Solaris realized that it is dangerous and undesirable to be forced to give someone root access just to perform one specific task. For example, just because a user may need to start a process that listens on a port below 1024 does not mean that they should also be able to bypass filesystem permissions, change network interface settings, or mount and unmount file systems. With the privilege subsystem in Solaris 10, it is possible to give a user just the specific capability that they need, for example, the ability to bind to privileged ports, without giving them full root access. Similarly, it is possible to take away privileges that might otherwise be available. For example, an account that is only used to run a specific daemon does not need to be able to see processes owned by other users on the system.
Administrators should consider Oracle Privileged Account Management system to achieve the best security level.
Oracle Unified Directory also has a privilege subsystem that defines distinct capabilities that users might need and makes it possible to give them just the level of access that they require. Regular users can be granted privileges that they would not otherwise have, certain privileges can be taken away from root users. The set of privileges currently defined in the directory server includes:
Allows the user to bypass access control evaluation
Allows the user to make changes to the access controls defined in the server
Allows the user to have read access to the server configuration
Allows the user to have write access to the server configuration
Allows the user to read JMX attribute values
Allows the user to update JMX attribute values
* Allows the user to subscribe to JMX notifications
Allows the user to request the LDIF import task
Allows the user to request the LDIF export task
Allows the user to request the backend backup task
Allows the user to request the backend restore task
Allows the user to request the server shutdown task
Allows the user to request the server restart task
Allows the user to use the proxied authorization control or request an alternate SASL authorization ID
Allows the user to terminate arbitrary client connections
* Allows the user to cancel arbitrary client requests
Allows the user to request unindexed search operations
Allows the user to reset the passwords for other users
Allows the user to update the server schema
Allows the user to change the set of privileges assigned to a user, or to change the set of default root privileges
At the present time, the privileges marked with an asterisk (*) are not yet implemented in the server and therefore have no effect.
The privilege subsystem is largely independent of the access control subsystem. Unless the user also has the
bypass-acl privilege, operations might still be subject to access control checking. For example, if a user has the
config-read privilege, that user can see only those parts of the configuration that are allowed by access control. As a rule, whenever an operation is covered by both the privilege subsystem and access control, both mechanisms must allow that operation.
By default, normal users are not granted any of the privileges described previously. Therefore, if a user should be allowed to perform any of the associated operations, they must be granted the appropriate privileges. This can be done by adding the
ds-privilege-name operational attribute to the user's entry.
Adding a privilege with a value such as
modify-acl is not sufficient for granting a user the right to add, replace, or delete an ACI. Appropriate access control for the user to modify the ACI for another entry is also required. See Appendix 8, "ACI Syntax" for more information.
ds-privilege-name is a multivalued attribute, and if a user is to be given multiple privileges, then a separate value should be used for each one. When the virtual attribute subsystem is in place, it should also be possible to grant privileges to groups of users automatically by making
ds-privilege-name a virtual attribute in those user entries.
As an example, the following modification can be used to add the
proxied-auth privilege to the user
dn: cn=Proxy User,dc=example,dc=com changetype: modify add: ds-privilege-name ds-privilege-name: proxied-auth
With the introduction of the privilege subsystem, the primary distinguishing characteristics of root users that separate them from other accounts in the server are that they exist in the configuration rather than in the user data, and that because they are root users they automatically inherit a certain set of privileges. The set of privileges automatically granted to root users is defined in the
ds-cfg-default-root-privilege-name attribute of the
cn=Root DNs,cn=config entry. By default, root users are automatically granted the following privileges:
If you want to alter the set of privileges that are automatically assigned to root users, then you may do so by editing the
ds-cfg-default-root-privilege-name attribute. Further, if you want to have a different set of privileges for a specific root user, then you can accomplish that using the
ds-privilege-name attribute in that root user's entry, just like for a normal user. For example, the following modification may be used to give a specific root user (in this case
cn=Test Root User,cn=Root DNs,cn=config) the ability to use proxied authorization while removing the ability to change user privileges or access the configuration. (The minus sign before the privilege indicates that it is being removed rather than granted.):
dn: cn=Test Root User,cn=Root DNs,cn=config changetype: modify add: ds-privilege-name ds-privilege-name: proxied-auth ds-privilege-name: -config-read ds-privilege-name: -config-write
In this case, the
cn=Test Root User,cn=Root DNs,cn=config user inherits all privileges automatically granted to root users with the exception of the
config-write privileges and is also given the