Provided by: krb5-admin-server_1.17-6_amd64 bug

NAME

       kadm5.acl - Kerberos ACL file

DESCRIPTION

       The  Kerberos  kadmind(8)  daemon  uses an Access Control List (ACL) file to manage access
       rights to the Kerberos database.  For operations that affect principals, the ACL file also
       controls which principals can operate on which other principals.

       The  default  location  of the Kerberos ACL file is /etc/krb5kdc/kadm5.acl  unless this is
       overridden by the acl_file variable in kdc.conf(5).

SYNTAX

       Empty lines and lines starting with the sharp sign (#) are ignored.  Lines containing  ACL
       entries have the format:

          principal  permissions  [target_principal  [restrictions] ]

       NOTE:
          Line  order in the ACL file is important.  The first matching entry will control access
          for an actor principal on a target principal.

       principal
              (Partially or fully qualified Kerberos principal  name.)  Specifies  the  principal
              whose permissions are to be set.

              Each component of the name may be wildcarded using the * character.

       permissions
              Specifies  what  operations  may  or may not be performed by a principal matching a
              particular entry.  This is a string of  one  or  more  of  the  following  list  of
              characters  or their upper-case counterparts.  If the character is upper-case, then
              the operation is disallowed.  If the character is lower-case, then the operation is
              permitted.

                                    ┌──┬──────────────────────────────────┐
                                    │a │ [Dis]allows   the   addition  of │
                                    │  │ principals or policies           │
                                    ├──┼──────────────────────────────────┤
                                    │c │ [Dis]allows  the   changing   of │
                                    │  │ passwords for principals         │
                                    ├──┼──────────────────────────────────┤
                                    │d │ [Dis]allows   the   deletion  of │
                                    │  │ principals or policies           │
                                    ├──┼──────────────────────────────────┤
                                    │e │ [Dis]allows  the  extraction  of │
                                    │  │ principal keys                   │
                                    ├──┼──────────────────────────────────┤
                                    │i │ [Dis]allows    inquiries   about │
                                    │  │ principals or policies           │
                                    ├──┼──────────────────────────────────┤
                                    │l │ [Dis]allows the listing  of  all │
                                    │  │ principals or policies           │
                                    ├──┼──────────────────────────────────┤
                                    │m │ [Dis]allows  the modification of │
                                    │  │ principals or policies           │
                                    ├──┼──────────────────────────────────┤
                                    │p │ [Dis]allows the  propagation  of │
                                    │  │ the  principal database (used in │
                                    │  │ incr_db_prop)                    │
                                    └──┴──────────────────────────────────┘

                                    │s │ [Dis]allows the explicit setting │
                                    │  │ of the key for a principal       │
                                    ├──┼──────────────────────────────────┤
                                    │x │ Short    for    admcilsp.    All │
                                    │  │ privileges (except e)            │
                                    ├──┼──────────────────────────────────┤
                                    │* │ Same as x.                       │
                                    └──┴──────────────────────────────────┘

       NOTE:
          The extract privilege is not included in the wildcard privilege; it must be  explicitly
          assigned.   This  privilege allows the user to extract keys from the database, and must
          be handled with great care to avoid disclosure of important  keys  like  those  of  the
          kadmin/*  or krbtgt/* principals.  The lockdown_keys principal attribute can be used to
          prevent key extraction from specific principals regardless of the granted privilege.

       target_principal
              (Optional. Partially or fully qualified Kerberos principal  name.)   Specifies  the
              principal  on  which permissions may be applied.  Each component of the name may be
              wildcarded using the * character.

              target_principal can also include back-references to principal,  in  which  *number
              matches the corresponding wildcard in principal.

       restrictions
              (Optional) A string of flags. Allowed restrictions are:

                 {+|-}flagname
                        flag  is  forced  to  the indicated value.  The permissible flags are the
                        same as those for the default_principal_flags variable in kdc.conf(5).

                 -clearpolicy
                        policy is forced to be empty.

                 -policy pol
                        policy is forced to be pol.

                 -{expire, pwexpire, maxlife, maxrenewlife} time
                        (getdate string) associated value will be forced to  MIN(time,  requested
                        value).

              The above flags act as restrictions on any add or modify operation which is allowed
              due to that ACL line.

       WARNING:
          If the kadmind ACL file is modified, the kadmind  daemon  needs  to  be  restarted  for
          changes to take effect.

EXAMPLE

       Here is an example of a kadm5.acl file:

          */admin@ATHENA.MIT.EDU    *                               # line 1
          joeadmin@ATHENA.MIT.EDU   ADMCIL                          # line 2
          joeadmin/*@ATHENA.MIT.EDU i   */root@ATHENA.MIT.EDU       # line 3
          */root@ATHENA.MIT.EDU     ci  *1@ATHENA.MIT.EDU           # line 4
          */root@ATHENA.MIT.EDU     l   *                           # line 5
          sms@ATHENA.MIT.EDU        x   * -maxlife 9h -postdateable # line 6

       (line  1)  Any  principal  in  the  ATHENA.MIT.EDU  realm  with  an admin instance has all
       administrative privileges except extracting keys.

       (lines 1-3) The user joeadmin has all permissions except extracting keys  with  his  admin
       instance,  joeadmin/admin@ATHENA.MIT.EDU  (matches  line 1).  He has no permissions at all
       with his null instance, joeadmin@ATHENA.MIT.EDU (matches line  2).   His  root  and  other
       non-admin,  non-null  instances (e.g., extra or dbadmin) have inquire permissions with any
       principal that has the instance root (matches line 3).

       (line 4) Any root principal in ATHENA.MIT.EDU can inquire or change the password of  their
       null instance, but not any other null instance.  (Here, *1 denotes a back-reference to the
       component matching the first wildcard in the actor principal.)

       (line 5) Any root principal in ATHENA.MIT.EDU can generate the list of principals  in  the
       database,  and  the  list of policies in the database.  This line is separate from line 4,
       because list permission can only be granted globally, not to specific target principals.

       (line 6) Finally, the Service  Management  System  principal  sms@ATHENA.MIT.EDU  has  all
       permissions except extracting keys, but any principal that it creates or modifies will not
       be able to get postdateable tickets or tickets with a life of longer than 9 hours.

MODULE BEHAVIOR

       The ACL file can coexist with other authorization modules in release 1.16  and  later,  as
       configured  in  the  kadm5_auth  section  of  krb5.conf(5).   The ACL file will positively
       authorize operations according to the rules above, but will never authoritatively deny  an
       operation,  so  other  modules can authorize operations in addition to those authorized by
       the ACL file.

       To operate without an ACL file, set the acl_file variable  in  kdc.conf(5)  to  the  empty
       string with acl_file = "".

SEE ALSO

       kdc.conf(5), kadmind(8)

AUTHOR

       MIT

COPYRIGHT

       1985-2019, MIT