LOGIN.CONF(5) FreeBSD File Formats Manual LOGIN.CONF(5)
NAME
login.conf - login class capability database
SYNOPSIS
/etc/login.conf, ~/.login_conf
DESCRIPTION
login.conf contains various attributes and capabilities of login classes.
A login class (an optional annotation against each record in the user
account database, /etc/master.passwd) determines session accounting,
resource limits and user environment settings. It is used by various
programs in the system to set up a user's login environment and to
enforce policy, accounting and administrative restrictions. It also
provides the means by which users are able to be authenticated to the
system and the types of authentication available. Attributes in addition
to the ones described here are available with third-party packages.
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 (`:') 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.
CAPABILITIES
Fields within each record in the database follow the getcap(3)
conventions for boolean, type string `=' and type numeric `#', although
type numeric is deprecated in favour of the string format and either form
is accepted for a numeric datum. Values fall into the following
categories:
bool If the name is present, then the boolean value is true;
otherwise, it is false
file Path name to a data file
program Path name to an executable file
list A list of values (or pairs of values) separated by commas or
spaces
path 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.)
number 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.
size A number which expresses a size. The default interpretation of
a value is the number of bytes, but a suffix may specify
alternate units:
b explicitly selects 512-byte blocks
k selects kilobytes (1024 bytes)
m specifies a multiplier of 1 megabyte (1048576
bytes),
g specifies units of gigabytes, and
t represents terabytes.
A size value is a numeric quantity and case of the suffix is not
significant. Concatenated values are added together. A size
value may be infinite.
time A period of time, by default in seconds. A prefix may specify a
different unit:
y indicates the number of 365 day years,
w indicates the number of weeks,
d the number of days,
h the number of hours,
m the number of minutes, and
s the number of seconds.
Concatenated values are added together. For example, 2 hours
and 40 minutes may be written either as 9600s, 160m or 2h40m. A
time value may be infinite.
"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.
RESOURCE LIMITS
Name Type Notes Description
coredumpsize size Maximum coredump size limit.
cputime time CPU usage limit.
datasize size Maximum data size limit.
filesize size Maximum file size limit.
maxproc number Maximum number of processes.
memorylocked size Maximum locked in core memory size
limit.
memoryuse size Maximum of core memory use size
limit.
openfiles number Maximum number of open files per
process.
sbsize size Maximum permitted socketbuffer
size.
vmemoryuse size Maximum permitted total VM usage
per process.
stacksize size Maximum stack size limit.
pseudoterminals number Maximum number of
pseudo-terminals.
swapuse size Maximum swap space size limit.
umtxp number 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.
ENVIRONMENT
Name Type Notes Description
charset string Set $MM_CHARSET environment
variable to the specified
value.
cpumask string List of cpus to bind the user
to. The syntax is the same as
for the -l argument of
cpuset(1) or the word
`default'. If set to
`default' no action is taken.
hushlogin bool false Same as having a ~/.hushlogin
file.
ignorenologin bool false Login not prevented by
nologin.
ftp-chroot bool false Limit FTP access with
chroot(2) to the HOME
directory of the user. See
ftpd(8) for details.
label string Default MAC policy; see
maclabel(7).
lang string Set $LANG environment
variable to the specified
value.
mail string Set $MAIL environment
variable to the specified
value.
manpath path Default search path for
manpages.
nocheckmail bool false Display mail status at login.
nologin file If the file exists it will be
displayed and the login
session will be terminated.
path path /bin /usr/bin Default search path.
priority number Initial priority (nice)
level.
requirehome bool false Require a valid home
directory to login.
setenv list A comma-separated list of
environment variables and
values to which they are to
be set.
shell prog Session shell to execute
rather than the shell
specified in the passwd file.
The SHELL environment
variable will contain the
shell specified in the
password file.
term string Default terminal type if not
able to determine from other
means.
timezone string Default value of $TZ
environment variable.
umask number 022 Initial umask. Should always
have a leading 0 to ensure
octal interpretation.
welcome file /etc/motd File containing welcome
message.
AUTHENTICATION
Name Type Notes Description
copyright file File containing additional copyright
information
host.allow list List of remote host wildcards from
which users in the class may access.
host.deny list List of remote host wildcards from
which users in the class may not
access.
login_prompt string The login prompt given by login(1)
login-backoff number 3 The number of login attempts allowed
before the backoff delay is inserted
after each subsequent attempt. The
backoff delay is the number of tries
above login-backoff multiplied by 5
seconds.
login-retries number 10 The number of login attempts allowed
before the login fails.
passwd_format string sha512 The encryption format that new or
changed passwords will use. Valid
values include "des", "md5", "blf",
"sha256" and "sha512"; see crypt(3)
for details. NIS clients using a
non-FreeBSD NIS server should
probably use "des".
passwd_prompt string The password prompt presented by
login(1)
passwordtime time Used by passwd(1) to set next
password expiry date.
times.allow list List of time periods during which
logins are allowed.
times.deny list List of time periods during which
logins are disallowed.
ttys.allow list List of ttys and ttygroups which
users in the class may use for
access.
ttys.deny list List of ttys and ttygroups which
users in the class may not use for
access.
warnexpire time Advance notice for pending account
expiry.
warnpassword time Advance notice for pending password
expiry.
These fields are intended to be used by passwd(1) and other programs in
the login authentication system.
Capabilities that set environment variables are scanned for both `~' and
`$' 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.
RESERVED CAPABILITIES
The following capabilities are reserved for the purposes indicated and
may be supported by third-party software. They are not implemented in
the base system.
Name Type Notes Description
accounted bool false Enable session time accounting for
all users in this class.
auth list passwd Allowed authentication styles. The
first item is the default style.
auth-type list Allowed authentication styles for
the authentication type.
autodelete time Time after expiry when account is
auto-deleted.
bootfull bool false Enable 'boot only if ttygroup is
full' strategy when terminating
sessions.
daytime time Maximum login time per day.
expireperiod time Time for expiry allocation.
graceexpire time Grace days for expired account.
gracetime time Additional grace login time
allowed.
host.accounted list List of remote host wildcards from
which login sessions will be
accounted.
host.exempt list List of remote host wildcards from
which login session accounting is
exempted.
idletime time Maximum idle time before logout.
minpasswordlen number 6 The minimum length a local password
may be.
mixpasswordcase bool true Whether passwd(1) will warn the
user if an all lower case password
is entered.
monthtime time Maximum login time per month.
refreshtime time New time allowed on account
refresh.
refreshperiod str How often account time is
refreshed.
sessiontime time Maximum login time per session.
sessionlimit number Maximum number of concurrent login
sessions on ttys in any group.
ttys.accounted list List of ttys and ttygroups for
which login accounting is active.
ttys.exempt list List of ttys and ttygroups for
which login accounting is exempt.
warntime time Advance notice for pending
out-of-time.
weektime time 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.
SEE ALSO
cap_mkdb(1), login(1), chroot(2), getcap(3), getttyent(3), login_cap(3),
login_class(3), pam(3), passwd(5), ttys(5), ftpd(8), pam_passwdqc(8)
HISTORY
The file login.conf first appeared in FreeBSD 2.1.5.
FreeBSD 13.1-RELEASE-p6 October 6, 2021 FreeBSD 13.1-RELEASE-p6
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