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AUDIT_CONTROL(5)          FreeBSD File Formats Manual         AUDIT_CONTROL(5)

NAME
     audit_control - audit system parameters

DESCRIPTION
     The audit_control file contains several audit system parameters.  Each
     line of this file is of the form:

           parameter:value

     The parameters are:

     dir     The directory where audit log files are stored.  There may be
             more than one of these entries.  Changes to this entry can only
             be enacted by restarting the audit system.  See audit(8) for a
             description of how to restart the audit system.

     dist    When set to on or yes, auditd(8) will be creating hardlinks to
             all trail files in /var/audit/dist directory.  Those hardlinks
             will be consumed by the auditdistd(8) daemon.

     flags   Specifies which audit event classes are audited for all users.
             audit_user(5) describes how to audit events for individual users.
             See the information below for the format of the audit flags.

     host    Specify the hostname or IP address to be used when setting the
             local systems's audit host information.  This hostname will be
             converted into an IP or IPv6 address and will be included in the
             header of each audit record.  Due to the possibility of transient
             errors coupled with the security issues in the DNS protocol
             itself, the use of DNS should be avoided.  Instead, it is
             strongly recommended that the hostname be specified in the
             /etc/hosts file.  For more information see hosts(5).

     naflags
             Contains the audit flags that define what classes of events are
             audited when an action cannot be attributed to a specific user.

     minfree
             The minimum free space required on the file system audit logs are
             being written to.  When the free space falls below this limit a
             warning will be issued.  If no value for the minimum free space
             is set, the default of 20 percent is applied by the kernel.

     policy  A list of global audit policy flags specifying various behaviors,
             such as fail stop, auditing of paths and arguments, etc.

     filesz  Maximum trail size in bytes; if set to a non-0 value, the audit
             daemon will rotate the audit trail file at around this size.
             Sizes less than the minimum trail size (default of 512K) will be
             rejected as invalid.  If 0, trail files will not be automatically
             rotated based on file size.  For convenience, the trail size may
             be expressed with suffix letters: B (Bytes), K (Kilobytes), M
             (Megabytes), or G (Gigabytes).  For example, 2M is the same as
             2097152.

     expire-after
             Specifies when audit log files will expire and be removed.  This
             may be after a time period has passed since the file was last
             written to or when the aggregate of all the trail files have
             reached a specified size or a combination of both.  If no expire-
             after parameter is given then audit log files will not expire and
             be removed by the audit control system.  See the information
             below for the format of the expiration specification.

AUDIT FLAGS
     Audit flags are a comma-delimited list of audit classes as defined in the
     audit_class(5) file.  Event classes may be preceded by a prefix which
     changes their interpretation.  The following prefixes may be used for
     each class:

           (none)  Record both successful and failed events.
           +       Record successful events.
           -       Record failed events.
           ^       Record neither successful nor failed events.
           ^+      Do not record successful events.
           ^-      Do not record failed events.

AUDIT POLICY FLAGS
     The policy flags field is a comma-delimited list of policy flags from the
     following list:

           cnt           Allow processes to continue running even though
                         events are not being audited.  If not set, processes
                         will be suspended when the audit store space is
                         exhausted.  Currently, this is not a recoverable
                         state.
           ahlt          Fail stop the system if unable to audit an
                         event--this consists of first draining pending
                         records to disk, and then halting the operating
                         system.
           argv          Audit command line arguments to execve(2).
           arge          Audit environmental variable arguments to execve(2).
           seq           Include a unique audit sequence number token in
                         generated audit records (not implemented on FreeBSD
                         or Darwin).
           group         Include supplementary groups list in generated audit
                         records (not implemented on FreeBSD or Darwin;
                         supplementary groups are never included in records on
                         these systems).
           trail         Append a trailer token to each audit record (not
                         implemented on FreeBSD or Darwin; trailers are always
                         included in records on these systems).
           path          Include secondary file paths in audit records (not
                         implemented on FreeBSD or Darwin; secondary paths are
                         never included in records on these systems).
           zonename      Include a zone ID token with each audit record (not
                         implemented on FreeBSD or Darwin; FreeBSD audit
                         records do not currently include the jail ID or
                         name).
           perzone       Enable auditing for each local zone (not implemented
                         on FreeBSD or Darwin; on FreeBSD, audit records are
                         collected from all jails and placed in a single
                         global trail, and only limited audit controls are
                         permitted within a jail).

     It is recommended that installations set the cnt flag but not ahlt flag
     unless it is intended that audit logs exceeding available disk space halt
     the system.

AUDIT LOG EXPIRATION SPECIFICATION
     The expiration specification can be one value or two values with the
     logical conjunction of AND/OR between them.  Values for the audit log
     file age are numbers with the following suffixes:

           s           Log file age in seconds.
           h           Log file age in hours.
           d           Log file age in days.
           y           Log file age in years.

     Values for the disk space used are numbers with the following suffixes:

           (space) or
           B           Disk space used in Bytes.
           K           Disk space used in Kilobytes.
           M           Disk space used in Megabytes.
           G           Disk space used in Gigabytes.

     The suffixes on the values are case sensitive.  If both an age and disk
     space value are used they are separated by AND or OR and both values are
     used to determine when audit log files expire.  In the case of AND, both
     the age and disk space conditions must be met before the log file is
     removed.  In the case of OR, either condition may expire the log file.
     For example:

           expire-after: 60d AND 1G

     will expire files that are older than 60 days but only if 1 gigabyte of
     disk space total is being used by the audit logs.

DEFAULT
     The following settings appear in the default audit_control file:

           dir:/var/audit
           flags:lo,aa
           minfree:5
           naflags:lo,aa
           policy:cnt,argv
           filesz:2M
           expire-after:10M

     The flags parameter above specifies the system-wide mask corresponding to
     login/logout as well as authentication and authorization events.  The
     policy parameter specifies that the system should neither fail stop nor
     suspend processes when the audit store fills and that command line
     arguments should be audited for AUE_EXECVE events.  The trail file will
     be automatically rotated by the audit daemon when the file size reaches
     approximately 2MB.  Trail files will expire when their aggregate size
     exceeds 10MB.

FILES
     /etc/security/audit_control

SEE ALSO
     auditon(2), audit(4), audit_class(5), audit_event(5), audit_user(5),
     audit(8), auditd(8)

HISTORY
     The OpenBSM implementation was created by McAfee Research, the security
     division of McAfee Inc., under contract to Apple Computer Inc. in 2004.
     It was subsequently adopted by the TrustedBSD Project as the foundation
     for the OpenBSM distribution.

AUTHORS
     This software was created by McAfee Research, the security research
     division of McAfee, Inc., under contract to Apple Computer Inc.
     Additional authors include Wayne Salamon, Robert Watson, and SPARTA Inc.

     The Basic Security Module (BSM) interface to audit records and audit
     event stream format were defined by Sun Microsystems.

FreeBSD 11.0-PRERELEASE          May 14, 2009          FreeBSD 11.0-PRERELEASE

NAME | DESCRIPTION | AUDIT FLAGS | AUDIT POLICY FLAGS | AUDIT LOG EXPIRATION SPECIFICATION | DEFAULT | FILES | SEE ALSO | HISTORY | AUTHORS

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