LOGIN.CONF(5) BSD File Formats Manual LOGIN.CONF(5)NAMElogin.conf — login class capability database
SYNOPSIS
/etc/login.conf, ~/.login_conf
DESCRIPTIONlogin.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 pro‐
vides the means by which users are able to be authenticated to the system
and the types of authentication available.
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.
In DragonFly, 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 capabili‐
ties may be overridden, typically those which do not involve authentica‐
tion, 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 charac‐
ters and blanks for readability.
See getcap(3) for a more in-depth description of the format of a capabil‐
ity database.
CAPABILITIES
Fields within each record in the database follow the getcap(3) conven‐
tions 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; other‐
wise, 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 (ie. the capability tag being delim‐
ited 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.
size A number which expresses a size. The default interpretation of
a value is the number of bytes, but a suffix may specify alter‐
nate 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.
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.
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.
posixlocks size Maximum number of POSIX-type advisory-mode
locks.
These resource limit entries actually specify both the maximum and cur‐
rent limits (see getrlimit(2)). The current (soft) limit is the one nor‐
mally used, although the user is permitted to increase the current limit
to the maximum (hard) limit. The maximum and current limits may be spec‐
ified 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.
hushlogin bool false Same as having a ~/.hushlogin
file.
ignorenologin bool false Login not prevented by
nologin.
lang string Set $LANG environment
variable to the specified
value.
manpath path Default search path for
manpages.
nologin file If the file exists it will be
displayed and the login ses‐
sion 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 speci‐
fied in the passwd file. The
SHELL environment variable
will contain the shell speci‐
fied in the password file.
term string Default terminal type if not
able to determine from other
means.
timezone string Default value of $TZ
environment variable.
umask number 022 Initial umask. Should always
have a leading 0 to ensure
octal interpretation.
welcome file /etc/motd File containing welcome
message.
AUTHENTICATION
Name Type Notes Description
copyright file File containing additional
copyright information
host.allow list List of remote host wildcards from
which users in the class may
access.
host.deny list List of remote host wildcards from
which users in the class may not
access.
login_prompt string The login prompt given by login(1)
minpasswordlen number 6 The minimum length a local password
may be.
mixpasswordcase bool true Whether passwd(1) will warn the
user if an all lower case password
is entered.
login-backoff number 3 The number of login attempts
allowed before the backoff delay is
inserted after each subsequent
attempt.
login-retries number 10 The number of login attempts
allowed before the login fails.
passwd_format string md5 The encryption format that new or
changed passwords will use. Valid
values include "des", "md5" and
"blf". NIS clients using a
non-DragonFly/FreeBSD NIS server
should probably use "des".
passwd_prompt string The password prompt presented by
login(1)
times.allow list List of time periods during which
logins are allowed.
times.deny list List of time periods during which
logins are disallowed.
ttys.allow list List of ttys and ttygroups which
users in the class may use for
access.
ttys.deny list List of ttys and ttygroups which
users in the class may not use for
access.
These fields are intended to be used by passwd(1) and other programs in
the login authentication system.
Capabilities that set environment variables are scanned for both ‘~’ and
‘$’ characters, which are substituted for a user's home directory and
name respectively. To pass these characters literally into the environ‐
ment 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 pro‐
grams for wildcard matching (See fnmatch(3) for details on the implemen‐
tation). 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 con‐
tains 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 peri‐
ods 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.
ACCOUNTING LIMITS
Name Type Notes Description
accounted bool false Enable session time accounting for
all users in this class.
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
(unused).
monthtime time Maximum login time per month.
passwordtime time Used by passwd(1) to set next pass‐
word expiry date.
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.
warnexpire time Advance notice for pending account
expiry.
warnpassword time Advance notice for pending password
expiry.
warntime time Advance notice for pending out-of-
time.
weektime time Maximum login time per week.
These fields are used by the time accounting system, which regulates,
controls and records user login access.
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 ALSOcap_mkdb(1), login(1), getcap(3), getttyent(3), login_cap(3),
login_class(3), passwd(5), ttys(5)BUGS
The idletime setting is not enforced.
BSD November 22, 1996 BSD
