A special record "default" in the system user class capability database /etc/login.conf is used automatically for any non-root user without a valid login class in /etc/master.passwd. A user with a uid of 0 without a valid login class will use the record "root" if it exists, or "default" if not.
Users may individually create a file called .login_conf in their home directory using the same format, consisting of a single entry with a record id of "me". If present, this file is used by login(1) to set user-defined environment settings which override those specified in the system login capabilities database. Only a subset of login capabilities may be overridden, typically those which do not involve authentication, resource limits and accounting.
Records in a class capabilities database consist of a number of colon-separated fields. The first entry for each record gives one or more names that a record is to be known by, each separated by a '|' character. The first name is the most common abbreviation. The last name given should be a long name that is more descriptive of the capability entry, and all others are synonyms. All names but the last should be in lower case and contain no blanks; the last name may contain upper case characters and blanks for readability.
Note that since a colon (‘:amp;’) is used to separate capability entries, a ‘\c’ escape sequence must be used to embed a literal colon in the value or name of a capability.
The default /etc/login.conf shipped with FreeBSD is an out of the box configuration. Whenever changes to this, or the user's ~/.login_conf, file are made, the modifications will not be picked up until cap_mkdb(1) is used to compile the file into a database. This database file will have a .db extension and is accessed through cgetent(3). See getcap(3) for a more in-depth description of the format of a capability database.
|If the name is present, then the boolean value is true; otherwise, it is false
|Path name to a data file
|Path name to an executable file
|A list of values (or pairs of values) separated by commas or spaces
|A space or comma separated list of path names, following the usual csh conventions (leading tilde with and without username being expanded to home directories etc.)
|A numeric value, either decimal (default), hexadecimal (with leading 0x), or octal (with a leading 0). With a numeric type, only one numeric value is allowed. Numeric types may also be specified in string format (i.e., the capability tag being delimited from the value by '=' instead of '#'). Whichever method is used, then all records in the database must use the same method to allow values to be correctly overridden in interpolated records. A numeric value may be infinite.
|A number which expresses a size. The default interpretation of a value is the number of bytes, but a suffix may specify alternate units:
|explicitly selects 512-byte blocks
|selects kilobytes (1024 bytes)
|specifies a multiplier of 1 megabyte (1048576 bytes),
|specifies units of gigabytes, and
|A period of time, by default in seconds. A prefix may specify a different unit:
|indicates the number of 365 day years,
|indicates the number of weeks,
|the number of days,
|the number of hours,
|the number of minutes, and
|the number of seconds.
"infinity", "inf", "unlimited", "unlimit," and -1 are considered infinite values.
The usual convention to interpolate capability entries using the special tc=value notation may be used.
|Name Ta Type Ta Notes
coredumpsize Ta size Ta
|Maximum coredump size limit.
cputime Ta time Ta
|CPU usage limit.
datasize Ta size Ta
|Maximum data size limit.
filesize Ta size Ta
|Maximum file size limit.
maxproc Ta number Ta
|Maximum number of processes.
memorylocked Ta size Ta
|Maximum locked in core memory size limit.
memoryuse Ta size Ta
|Maximum of core memory use size limit.
openfiles Ta number Ta
|Maximum number of open files per process.
sbsize Ta size Ta
|Maximum permitted socketbuffer size.
vmemoryuse Ta size Ta
|Maximum permitted total VM usage per process.
stacksize Ta size Ta
|Maximum stack size limit.
pseudoterminals Ta number Ta
|Maximum number of pseudo-terminals.
swapuse Ta size Ta
|Maximum swap space size limit.
umtxp Ta number Ta
|Maximum number of process-shared pthread locks.
These resource limit entries actually specify both the maximum and current limits (see getrlimit(2)). The current (soft) limit is the one normally used, although the user is permitted to increase the current limit to the maximum (hard) limit. The maximum and current limits may be specified individually by appending a -max or -cur to the capability name.
|Name Ta Type Ta Notes
charset Ta string Ta
|Set $MM_CHARSET environment variable to the specifiedvalue.
cpumask Ta string Ta
| List of cpus to bind the user to.The syntax is the same as for the
hushlogin Ta bool Ta false
|Same as having a ~/.hushlogin file.
ignorenologin Ta bool Ta false
|Login not prevented by nologin.
ftp-chroot Ta bool Ta false
|Limit FTP access withchroot(2) to the HOME directory of the user. See ftpd(8) for details.
label Ta string Ta
|Default MAC policy; seemaclabel(7).
lang Ta string Ta
|Set $LANG environment variable to the specified value.
mail Ta string Ta
|Set $MAIL environment variable to the specified value.
manpath Ta path Ta
|Default search path for manpages.
nocheckmail Ta bool Ta false
|Display mail status at login.
nologin Ta file Ta
|If the file exists it will be displayed andthe login session will be terminated.
path Ta path Ta /bin /usr/bin
|Default search path.
priority Ta number Ta
|Initial priority (nice) level.
requirehome Ta bool Ta false
|Require a valid home directory to login.
setenv Ta list Ta
|A comma-separated list of environment variables andvalues to which they are to be set.
shell Ta prog Ta
|Session shell to execute rather than theshell specified in the passwd file. The SHELL environment variable will contain the shell specified in the password file.
term Ta string Ta
|Default terminal type if not able to determinefrom other means.
timezone Ta string Ta
|Default value of $TZ environment variable.
umask Ta number Ta 022
|Initial umask. Should always have a leading 0 toensure octal interpretation.
welcome Ta file Ta /etc/motd
|File containing welcome message.
|Name Ta Type Ta Notes
copyright Ta file Ta
|File containing additional copyright information
host.allow Ta list Ta
|List of remote host wildcards from which users inthe class may access.
host.deny Ta list Ta
|List of remote host wildcards from which usersin the class may not access.
login_prompt Ta string Ta
|The login prompt given bylogin(1)
login-backoff Ta number Ta 3
|The number of login attemptsallowed before the backoff delay is inserted after each subsequent attempt. The backoff delay is the number of tries above login-backoff multiplied by 5 seconds.
login-retries Ta number Ta 10
|The number of login attemptsallowed before the login fails.
passwd_format Ta string Ta sha512
|The encryption format that new orchanged passwords will use. Valid values include "des", "md5", "blf", "sha256" and "sha512"; see crypt(3) for details. NIS clients using a non-Fx NIS server should probably use "des".
passwd_prompt Ta string Ta
|The password prompt presented bylogin(1)
passwordtime Ta time Ta
|Used bypasswd(1) to set next password expiry date.
times.allow Ta list Ta
|List of time periods during whichlogins are allowed.
times.deny Ta list Ta
|List of time periods during which logins aredisallowed.
ttys.allow Ta list Ta
|List of ttys and ttygroups which usersin the class may use for access.
ttys.deny Ta list Ta
|List of ttys and ttygroups which usersin the class may not use for access.
warnexpire Ta time Ta
|Advance notice for pending account expiry.
warnpassword Ta time Ta
|Advance notice for pending password expiry.
These fields are intended to be used by passwd(1) and other programs in the login authentication system.
Capabilities that set environment variables are scanned for both ‘amp;~’ and ‘amp;$’ characters, which are substituted for a user's home directory and name respectively. To pass these characters literally into the environment variable, escape the character by preceding it with a backslash '\'.
The host.allow and host.deny entries are comma separated lists used for checking remote access to the system, and consist of a list of hostnames and/or IP addresses against which remote network logins are checked. Items in these lists may contain wildcards in the form used by shell programs for wildcard matching (See fnmatch(3) for details on the implementation). The check on hosts is made against both the remote system's Internet address and hostname (if available). If both lists are empty or not specified, then logins from any remote host are allowed. If host.allow contains one or more hosts, then only remote systems matching any of the items in that list are allowed to log in. If host.deny contains one or more hosts, then a login from any matching hosts will be disallowed.
The times.allow and times.deny entries consist of a comma-separated list of time periods during which the users in a class are allowed to be logged in. These are expressed as one or more day codes followed by a start and end times expressed in 24 hour format, separated by a hyphen or dash. For example, MoThSa0200-1300 translates to Monday, Thursday and Saturday between the hours of 2 am and 1 p.m.. If both of these time lists are empty, users in the class are allowed access at any time. If times.allow is specified, then logins are only allowed during the periods given. If times.deny is specified, then logins are denied during the periods given, regardless of whether one of the periods specified in times.allow applies.
Note that login(1) enforces only that the actual login falls within periods allowed by these entries. Further enforcement over the life of a session requires a separate daemon to monitor transitions from an allowed period to a non-allowed one.
The ttys.allow and ttys.deny entries contain a comma-separated list of tty devices (without the /dev/ prefix) that a user in a class may use to access the system, and/or a list of ttygroups (See getttyent(3) and ttys(5) for information on ttygroups). If neither entry exists, then the choice of login device used by the user is unrestricted. If only ttys.allow is specified, then the user is restricted only to ttys in the given group or device list. If only ttys.deny is specified, then the user is prevented from using the specified devices or devices in the group. If both lists are given and are non-empty, the user is restricted to those devices allowed by ttys.allow that are not available by ttys.deny.
The minpasswordlen and minpasswordcase facilities for enforcing restrictions on password quality, which used to be supported by login.conf, have been superseded by the pam_passwdqc(8) PAM module.
|Name Ta Type Ta Notes
accounted Ta bool Ta false
|Enable session time accounting for all usersin this class.
auth Ta list Ta passwd
|Allowed authentication styles.The first item is the default style.
|Allowed authentication styles for theauthentication type.
autodelete Ta time Ta
|Time after expiry when account is auto-deleted.
bootfull Ta bool Ta false
|Enable 'boot only if ttygroup is full' strategywhen terminating sessions.
daytime Ta time Ta
|Maximum login time per day.
expireperiod Ta time Ta
|Time for expiry allocation.
graceexpire Ta time Ta
|Grace days for expired account.
gracetime Ta time Ta
|Additional grace login time allowed.
host.accounted Ta list Ta
|List of remote host wildcards from whichlogin sessions will be accounted.
host.exempt Ta list Ta
|List of remote host wildcards from whichlogin session accounting is exempted.
idletime Ta time Ta
|Maximum idle time before logout.
minpasswordlen Ta number Ta 6
|The minimum length a localpassword may be.
mixpasswordcase Ta bool Ta true
|Whetherpasswd(1) will warn the user if an all lower case password is entered.
monthtime Ta time Ta
|Maximum login time per month.
refreshtime Ta time Ta
|New time allowed on account refresh.
refreshperiod Ta str Ta
|How often account time is refreshed.
sessiontime Ta time Ta
|Maximum login time per session.
sessionlimit Ta number Ta
|Maximum number of concurrentlogin sessions on ttys in any group.
ttys.accounted Ta list Ta
|List of ttys and ttygroups for whichlogin accounting is active.
ttys.exempt Ta list Ta
|List of ttys and ttygroups for which login accountingis exempt.
warntime Ta time Ta
|Advance notice for pending out-of-time.
weektime Ta time Ta
|Maximum login time per week.
The ttys.accounted and ttys.exempt fields operate in a similar manner to ttys.allow and ttys.deny as explained above. Similarly with the host.accounted and host.exempt lists.
|October 6, 2021
|Not only is UNIX dead, it's starting to smell really bad.
|— Rob Pike