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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.	 Cur-
		     rently, 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; supplemen-
		     tary groups are never included in records on these	sys-
		     tems).
	   trail     Append a trailer token to each audit record (not imple-
		     mented on FreeBSD or Darwin; trailers are always included
		     in	records	on these systems).
	   path	     Include secondary file paths in audit records (not	imple-
		     mented 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 col-
		     lected 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 log-
     ical 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	argu-
     ments 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 divi-
     sion 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	9.2			 May 14, 2009			   FreeBSD 9.2

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

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