appropriate_privilege(5)       DG/UX R4.11MU05      appropriate_privilege(5)


NAME
       appropriate_privilege, privilege, capability - define terms related
       to privilege

DESCRIPTION
       This man page defines the terms privilege, capability, and
       appropriate privilege and identifies some of the differences that
       exist between a generic DG/UX system and a DG/UX system with
       information security.

   Privilege
       Privilege is a user's ability to perform an action on a computer
       system.  On a generic DG/UX system, the amount of privilege a user
       has is based on his/her identity: his/her user ID (UID) or group ID
       (GID). A regular user has few privileges, and the superuser, who logs
       in as root and has a UID of 0, has virtually unlimited privilege.
       Regular users may, for example, access their own files or files owned
       by their group, change access control lists (ACLs) on files they own,
       and cancel their own print jobs.  A superuser, on the other hand, has
       the privilege to perform all restricted operations, such as mounting
       a file system or adding a new user to the system, and to override
       access control policies, such as writing to a file whose access
       permissions disallow writing.

   Capability
       By comparison, the features of a DG/UX system with information
       security exert more control over the privileges its users have.  The
       capability feature associates certain privileges with each and every
       user on the system and with many of the executable objects on the
       system.  Users can perform only the actions permitted by their
       privileges. If the user does not have the specific capability
       required to perform an action, the action will fail.

       The authority to perform specific actions is associated with a
       capability that may be enabled or disabled for a given user.  One
       capability might grant the privilege to mount a file system, another
       the privilege to override access permissions denying read access to a
       file, and yet another the privilege to add users to the system.  The
       capability mechanism enables your site to grant or deny specific
       privileges to people according to their authorized tasks, not
       according to the "all or nothing" scheme in a generic UNIX system.

       A user's capabilities are defined by administrators with the
       authority known as appropriate privilege (defined below).  For
       example, an administrator, when adding a new user to the system,
       selects the capabilities that that user will need to perform his/her
       authorized tasks. Each time that user logs in to the system or
       otherwise creates a new session under his/her own UID, the user will
       have the capabilities included in his/her user account.

       Executable objects on the system may also have one or more
       capabilities.  Most of these are defined by administrators with
       appropriate privilege.

       Another difference between a generic DG/UX system and a system with
       capability, is that the capability system, by default, has no
       superuser.  Instead, users assume administrative roles; a role is a
       special account that enables the user to manage part of the system
       without having all privileges available on the system.  Each role has
       appropriate privilege to perform specific restricted operations
       and/or to override specific access controls.

   Appropriate Privilege
       Appropriate privilege is originally a POSIX concept (POSIX.1 [IOSO
       9945-1]) that Data General has implemented through its Capability
       mechanism. It is defined as a user's ability to perform a specific
       restricted operation or to override a particular access control
       policy, as determined by the capabilities enabled for the user.  On a
       generic DG/UX system, you have appropriate privilege if you are
       superuser (UID=0). On a DG/UX system with information security,
       appropriate privilege is granted when one or more specific
       capabilities is enabled in the effective capability set of the user.
       See the cap_defaults(5) security man page for more information about
       effective capability sets.

SEE ALSO
       cap_defaults(5), security(5).
       Using Security Features on the DG/UX(®) System in the security
       documentation set.



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