login.conf

LOGIN.CONF(5)                BSD 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)
     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.
     passwordtime      time                Used by passwd(1) to set next
                                           password 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.
     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.

BSD                               May 10, 2020                               BSD