1.\" Copyright (c) 2004-2009 Apple Inc. 2.\" Copyright (c) 2006 Robert N. M. Watson 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. Neither the name of Apple Inc. ("Apple") nor the names of 14.\" its contributors may be used to endorse or promote products derived 15.\" from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR 21.\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 25.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 26.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27.\" POSSIBILITY OF SUCH DAMAGE. 28.\" 29.Dd May 14, 2009 30.Dt AUDIT_CONTROL 5 31.Os 32.Sh NAME 33.Nm audit_control 34.Nd "audit system parameters" 35.Sh DESCRIPTION 36The 37.Nm 38file contains several audit system parameters. 39Each line of this file is of the form: 40.Pp 41.D1 Ar parameter Ns : Ns Ar value 42.Pp 43The parameters are: 44.Bl -tag -width indent 45.It Va dir 46The directory where audit log files are stored. 47There may be more than one of these entries. 48Changes to this entry can only be enacted by restarting the 49audit system. 50See 51.Xr audit 8 52for a description of how to restart the audit system. 53.It Va dist 54When set to 55.Va on 56or 57.Va yes , 58.Xr auditd 8 59will be creating hardlinks to all trail files in 60.Pa /var/audit/dist 61directory. 62Those hardlinks will be consumed by the 63.Xr auditdistd 8 64daemon. 65.It Va flags 66Specifies which audit event classes are audited for all users. 67.Xr audit_user 5 68describes how to audit events for individual users. 69See the information below for the format of the audit flags. 70.It Va host 71Specify the hostname or IP address to be used when setting the local 72systems's audit host information. 73This hostname will be converted into an IP or IPv6 address and will 74be included in the header of each audit record. 75Due to the possibility of transient errors coupled with the 76security issues in the DNS protocol itself, the use of DNS 77should be avoided. 78Instead, it is strongly recommended that the hostname be 79specified in the /etc/hosts file. 80For more information see 81.Xr hosts 5 . 82.It Va naflags 83Contains the audit flags that define what classes of events are audited when 84an action cannot be attributed to a specific user. 85.It Va minfree 86The minimum free space required on the file system audit logs are being written to. 87When the free space falls below this limit a warning will be issued. 88If no value for the minimum free space is set, the default of 20 percent is 89applied by the kernel. 90.It Va policy 91A list of global audit policy flags specifying various behaviors, such as 92fail stop, auditing of paths and arguments, etc. 93.It Va filesz 94Maximum trail size in bytes; if set to a non-0 value, the audit daemon will 95rotate the audit trail file at around this size. 96Sizes less than the minimum trail size (default of 512K) will be rejected as 97invalid. 98If 0, trail files will not be automatically rotated based on file size. 99For convenience, the trail size may be expressed with suffix letters: 100B (Bytes), K (Kilobytes), M (Megabytes), or G (Gigabytes). 101For example, 2M is the same as 2097152. 102.It Va expire-after 103Specifies when audit log files will expire and be removed. 104This may be after a time period has passed since the file was last 105written to or when the aggregate of all the trail files have reached a 106specified size or a combination of both. 107If no expire-after parameter is given then audit log files will not 108expire and be removed by the audit control system. 109See the information below for the format of the expiration 110specification. 111.El 112.Sh AUDIT FLAGS 113Audit flags are a comma-delimited list of audit classes as defined in the 114.Xr audit_class 5 115file. 116Event classes may be preceded by a prefix which changes their interpretation. 117The following prefixes may be used for each class: 118.Pp 119.Bl -tag -width indent -compact -offset indent 120.It (none) 121Record both successful and failed events. 122.It Li + 123Record successful events. 124.It Li - 125Record failed events. 126.It Li ^ 127Record neither successful nor failed events. 128.It Li ^+ 129Do not record successful events. 130.It Li ^- 131Do not record failed events. 132.El 133.Sh AUDIT POLICY FLAGS 134The policy flags field is a comma-delimited list of policy flags from the 135following list: 136.Pp 137.Bl -tag -width ".Cm zonename" -compact -offset indent 138.It Cm cnt 139Allow processes to continue running even though events are not being audited. 140If not set, processes will be suspended when the audit store space is 141exhausted. 142Currently, this is not a recoverable state. 143.It Cm ahlt 144Fail stop the system if unable to audit an event\[em]this consists of first 145draining pending records to disk, and then halting the operating system. 146.It Cm argv 147Audit command line arguments to 148.Xr execve 2 . 149.It Cm arge 150Audit environmental variable arguments to 151.Xr execve 2 . 152.It Cm seq 153Include a unique audit sequence number token in generated audit records (not 154implemented on 155.Fx 156or Darwin). 157.It Cm group 158Include supplementary groups list in generated audit records (not implemented 159on 160.Fx 161or Darwin; supplementary groups are never included in records on 162these systems). 163.It Cm trail 164Append a trailer token to each audit record (not implemented on 165.Fx 166or 167Darwin; trailers are always included in records on these systems). 168.It Cm path 169Include secondary file paths in audit records (not implemented on 170.Fx 171or 172Darwin; secondary paths are never included in records on these systems). 173.It Cm zonename 174Include a zone ID token with each audit record (not implemented on 175.Fx 176or 177Darwin; 178.Fx 179audit records do not currently include the jail ID or name). 180.It Cm perzone 181Enable auditing for each local zone (not implemented on 182.Fx 183or Darwin; on 184.Fx , 185audit records are collected from all jails and placed in a single 186global trail, and only limited audit controls are permitted within a jail). 187.El 188.Pp 189It is recommended that installations set the 190.Cm cnt 191flag but not 192.Cm ahlt 193flag unless it is intended that audit logs exceeding available disk space 194halt the system. 195.Sh AUDIT LOG EXPIRATION SPECIFICATION 196The expiration specification can be one value or two values with the 197logical conjunction of AND/OR between them. 198Values for the audit log file age are numbers with the following 199suffixes: 200.Pp 201.Bl -tag -width "(space) or" -compact -offset indent 202.It Li s 203Log file age in seconds. 204.It Li h 205Log file age in hours. 206.It Li d 207Log file age in days. 208.It Li y 209Log file age in years. 210.El 211.Pp 212Values for the disk space used are numbers with the following suffixes: 213.Pp 214.Bl -tag -width "(space) or" -compact -offset indent 215.It (space) or 216.It Li B 217Disk space used in Bytes. 218.It Li K 219Disk space used in Kilobytes. 220.It Li M 221Disk space used in Megabytes. 222.It Li G 223Disk space used in Gigabytes. 224.El 225.Pp 226The suffixes on the values are case sensitive. 227If both an age and disk space value are used they are separated by 228AND or OR and both values are used to determine when audit 229log files expire. 230In the case of AND, both the age and disk space conditions must be met 231before the log file is removed. 232In the case of OR, either condition may expire the log file. 233For example: 234.Bd -literal -offset indent 235expire-after: 60d AND 1G 236.Ed 237.Pp 238will expire files that are older than 60 days but only if 1 239gigabyte of disk space total is being used by the audit logs. 240.Sh DEFAULT 241The following settings appear in the default 242.Nm 243file: 244.Bd -literal -offset indent 245dir:/var/audit 246flags:lo,aa 247minfree:5 248naflags:lo,aa 249policy:cnt,argv 250filesz:2M 251expire-after:10M 252.Ed 253.Pp 254The 255.Va flags 256parameter above specifies the system-wide mask corresponding to login/logout 257as well as authentication and authorization events. 258The 259.Va policy 260parameter specifies that the system should neither fail stop nor suspend 261processes when the audit store fills and that command line arguments should 262be audited for 263.Dv AUE_EXECVE 264events. 265The trail file will be automatically rotated by the audit daemon when the 266file size reaches approximately 2MB. 267Trail files will expire when their aggregate size exceeds 10MB. 268.Sh FILES 269.Bl -tag -width ".Pa /etc/security/audit_control" -compact 270.It Pa /etc/security/audit_control 271.El 272.Sh SEE ALSO 273.Xr auditon 2 , 274.Xr audit 4 , 275.Xr audit_class 5 , 276.Xr audit_event 5 , 277.Xr audit_user 5 , 278.Xr audit 8 , 279.Xr auditd 8 280.Sh HISTORY 281The OpenBSM implementation was created by McAfee Research, the security 282division of McAfee Inc., under contract to Apple Computer Inc.\& in 2004. 283It was subsequently adopted by the TrustedBSD Project as the foundation for 284the OpenBSM distribution. 285.Sh AUTHORS 286.An -nosplit 287This software was created by McAfee Research, the security research division 288of McAfee, Inc., under contract to Apple Computer Inc. 289Additional authors include 290.An Wayne Salamon , 291.An Robert Watson , 292and SPARTA Inc. 293.Pp 294The Basic Security Module (BSM) interface to audit records and audit event 295stream format were defined by Sun Microsystems. 296