d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
8952729381
freebsd-dev/lib/libutil/login.conf.5
Ed Schouten bc093719ca Integrate the new MPSAFE TTY layer to the FreeBSD operating system. 
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

  The old TTY layer has a driver model that is not abstract enough to
  make it friendly to use. A good example is the output path, where the
  device drivers directly access the output buffers. This means that an
  in-kernel PPP implementation must always convert network buffers into
  TTY buffers.

  If a PPP implementation would be built on top of the new TTY layer
  (still needs a hooks layer, though), it would allow the PPP
  implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

  With the old TTY layer, it isn't entirely safe to destroy TTY's from
  the system. This implementation has a two-step destructing design,
  where the driver first abandons the TTY. After all threads have left
  the TTY, the TTY layer calls a routine in the driver, which can be
  used to free resources (unit numbers, etc).

  The pts(4) driver also implements this feature, which means
  posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

  One of the major improvements is the per-TTY mutex, which is expected
  to improve scalability when compared to the old Giant locking.
  Another change is the unbuffered copying to userspace, which is both
  used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from:		//depot/projects/mpsafetty/...
Approved by:		philip (ex-mentor)
Discussed:		on the lists, at BSDCan, at the DevSummit
Sponsored by:		Snow B.V., the Netherlands
dcons(4) fixed by:	kan
2008-08-20 08:31:58 +00:00

460 lines
16 KiB
Groff
Raw Blame History

.\" Copyright (c) 1996 David Nugent <davidn@blaze.net.au>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, is permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice immediately at the beginning of the file, without modification,
.\" this list of conditions, and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. This work was done expressly for inclusion into FreeBSD. Other use
.\" is permitted provided this notation is included.
.\" 4. Absolutely no warranty of function or purpose is made by the author
.\" David Nugent.
.\" 5. Modifications may be freely made to this file providing the above
.\" conditions are met.
.\"
.\" $FreeBSD$
.\"
.Dd August 20, 2008
.Dt LOGIN.CONF 5
.Os
.Sh NAME
.Nm login.conf
.Nd login class capability database
.Sh SYNOPSIS
.Pa /etc/login.conf ,
.Pa ~/.login_conf
.Sh DESCRIPTION
.Nm
contains various attributes and capabilities of login classes.
A login class (an optional annotation against each record in the user
account database,
.Pa /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.
.Pp
A special record "default" in the system user class capability database
.Pa /etc/login.conf
is used automatically for any
non-root user without a valid login class in
.Pa /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.
.Pp
In
.Fx ,
users may individually create a file called
.Pa .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
.Xr 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.
.Pp
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.
.Pp
Note that since a colon
.Pq Ql :\&
is used to separate capability entries, a
.Ql \ec
escape sequence must be used to embed a literal colon in the
value or name of a capability.
.Pp
The default
.Pa /etc/login.conf
shipped with
.Fx
is an out of the box configuration.
Whenever changes to this, or
the user's
.Pa ~/.login_conf ,
file are made, the modifications will not be picked up until
.Xr cap_mkdb 1
is used to compile the file into a database.
This database file will have a
.Pa .db
extension and is accessed through
.Xr cgetent 3 .
See
.Xr getcap 3
for a more in-depth description of the format of a capability database.
.Sh CAPABILITIES
Fields within each record in the database follow the
.Xr getcap 3
conventions for boolean, type string
.Ql \&=
and type numeric
.Ql \&# ,
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:
.Bl -tag -width "program"
.It bool
If the name is present, then the boolean value is true; otherwise, it is
false
.It file
Path name to a data file
.It program
Path name to an executable file
.It list
A list of values (or pairs of values) separated by commas or spaces
.It 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.)
.It 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.
.It 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:
.Bl -tag -offset indent -compact -width xxxx
.It b
explicitly selects 512-byte blocks
.It k
selects kilobytes (1024 bytes)
.It m
specifies a multiplier of 1 megabyte (1048576 bytes),
.It g
specifies units of gigabytes, and
.It t
represents terabytes.
.El
A size value is a numeric quantity and case of the suffix is not significant.
Concatenated values are added together.
.It time
A period of time, by default in seconds.
A prefix may specify a different unit:
.Bl -tag -offset indent -compact -width xxxx
.It y
indicates the number of 365 day years,
.It w
indicates the number of weeks,
.It d
the number of days,
.It h
the number of hours,
.It m
the number of minutes, and
.It s
the number of seconds.
.El
Concatenated values are added together.
For example, 2 hours and 40 minutes may be written either as
9600s, 160m or 2h40m.
.El
.Pp
The usual convention to interpolate capability entries using the special
.Em tc=value
notation may be used.
.Sh RESOURCE LIMITS
.Bl -column pseudoterminals indent indent
.It Sy "Name Type Notes Description
.It "coredumpsize size Maximum coredump size limit.
.It "cputime time CPU usage limit.
.It "datasize size Maximum data size limit.
.It "filesize size Maximum file size limit.
.It "maxproc number Maximum number of processes.
.It "memorylocked size Maximum locked in core memory size limit.
.It "memoryuse size Maximum of core memory use size limit.
.It "openfiles number Maximum number of open files per process.
.It "sbsize size Maximum permitted socketbuffer size.
.It "vmemoryuse size Maximum permitted total VM usage per process.
.It "stacksize size Maximum stack size limit.
.It "pseudoterminals number Maximum number of pseudo-terminals.
.El
.Pp
These resource limit entries actually specify both the maximum
and current limits (see
.Xr 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.
.Sh ENVIRONMENT
.Bl -column ignorenologin indent xbinxxusrxbin
.It Sy "Name Type Notes Description
.It "charset string Set $MM_CHARSET environment variable to the specified
value.
.It "cpumask string List of cpus to bind the user to.
The syntax is the same as for the
.Fl l
argument of
.Xr cpuset 1 or the word
.Ql default .
If set to
.Ql default
no action is taken.
.It "hushlogin bool false Same as having a ~/.hushlogin file.
.It "ignorenologin bool false Login not prevented by nologin.
.It "ftp-chroot bool false Limit FTP access with
.Xr chroot 2
to the
.Ev HOME
directory of the user.
See
.Xr ftpd 8
for details.
.It "label string Default MAC policy; see
.Xr maclabel 7 .
.It "lang string Set $LANG environment variable to the specified value.
.It "manpath path Default search path for manpages.
.It "nocheckmail bool false Display mail status at login.
.It "nologin file If the file exists it will be displayed and
the login session will be terminated.
.It "path path /bin /usr/bin Default search path.
.It "priority number Initial priority (nice) level.
.It "requirehome bool false Require a valid home directory to login.
.It "setenv list A comma-separated list of environment variables and
values to which they are to be set.
.It "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.
.It "term string Default terminal type if not able to determine
from other means.
.It "timezone string Default value of $TZ environment variable.
.It "umask number 022 Initial umask. Should always have a leading 0 to
ensure octal interpretation.
.It "welcome file /etc/motd File containing welcome message.
.El
.Sh AUTHENTICATION
.Bl -column passwd_prompt indent indent
.It Sy "Name Type Notes Description
.\" .It "approve program Program to approve login.
.It "copyright file File containing additional copyright information
.It "host.allow list List of remote host wildcards from which users in
the class may access.
.It "host.deny list List of remote host wildcards from which users
in the class may not access.
.It "login_prompt string The login prompt given by
.Xr login 1
.It "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
.Em login-backoff
multiplied by 5 seconds.
.It "login-retries number 10 The number of login attempts
allowed before the login fails.
.It "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
.No non- Ns Fx
NIS server should probably use "des".
.It "passwd_prompt string The password prompt presented by
.Xr login 1
.It "times.allow list List of time periods during which
logins are allowed.
.It "times.deny list List of time periods during which logins are
disallowed.
.It "ttys.allow list List of ttys and ttygroups which users
in the class may use for access.
.It "ttys.deny list List of ttys and ttygroups which users
in the class may not use for access.
.It "warnexpire time Advance notice for pending account expiry.
.It "warnpassword time Advance notice for pending password expiry.
.\".It "widepasswords bool false Use the wide password format. The wide password
.\" format allows up to 128 significant characters in the password.
.El
.Pp
These fields are intended to be used by
.Xr passwd 1
and other programs in the login authentication system.
.Pp
Capabilities that set environment variables are scanned for both
.Ql \&~
and
.Ql \&$
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 '\\'.
.Pp
The
.Em host.allow
and
.Em 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
.Xr 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.
.Pp
The
.Em times.allow
and
.Em 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
.Em times.allow
is specified, then logins are only allowed during the periods given.
If
.Em times.deny
is specified, then logins are denied during the periods given, regardless of whether
one of the periods specified in
.Em times.allow
applies.
.Pp
Note that
.Xr 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.
.Pp
The
.Em ttys.allow
and
.Em 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
.Xr getttyent 3
and
.Xr ttys 5
for information on ttygroups).
If neither entry exists, then the choice of login device used by the user is
unrestricted.
If only
.Em ttys.allow
is specified, then the user is restricted only to ttys in the given
group or device list.
If only
.Em 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.
.Pp
The
.Em minpasswordlen
and
.Em minpasswordcase
facilities for enforcing restrictions on password quality, which used
to be supported by
.Nm ,
have been superseded by the
.Xr pam_passwdqc 8
PAM module.
.Sh 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.
.Bl -column host.accounted indent indent
.It Sy "Name Type Notes Description
.It "accounted bool false Enable session time accounting for all users
in this class.
.It "auth list passwd Allowed authentication styles.
The first item is the default style.
.It "auth-" Ns Ar type Ta "list Allowed authentication styles for the
authentication
.Ar type .
.It "autodelete time Time after expiry when account is auto-deleted.
.It "bootfull bool false Enable 'boot only if ttygroup is full' strategy
when terminating sessions.
.It "daytime time Maximum login time per day.
.It "expireperiod time Time for expiry allocation.
.It "graceexpire time Grace days for expired account.
.It "gracetime time Additional grace login time allowed.
.It "host.accounted list List of remote host wildcards from which
login sessions will be accounted.
.It "host.exempt list List of remote host wildcards from which
login session accounting is exempted.
.It "idletime time Maximum idle time before logout.
.It "minpasswordlen number 6 The minimum length a local
password may be.
.It "mixpasswordcase bool true Whether
.Xr passwd 1
will warn the user if an all lower case password is entered.
.It "monthtime time Maximum login time per month.
.It "passwordtime time Used by
.Xr passwd 1
to set next password expiry date.
.It "refreshtime time New time allowed on account refresh.
.It "refreshperiod str How often account time is refreshed.
.It "sessiontime time Maximum login time per session.
.It "sessionlimit number Maximum number of concurrent
login sessions on ttys in any group.
.It "ttys.accounted list List of ttys and ttygroups for which
login accounting is active.
.It "ttys.exempt list List of ttys and ttygroups for which login accounting
is exempt.
.It "warntime time Advance notice for pending out-of-time.
.It "weektime time Maximum login time per week.
.El
.Pp
The
.Em ttys.accounted
and
.Em ttys.exempt
fields operate in a similar manner to
.Em ttys.allow
and
.Em ttys.deny
as explained
above.
Similarly with the
.Em host.accounted
and
.Em host.exempt
lists.
.Sh SEE ALSO
.Xr cap_mkdb 1 ,
.Xr login 1 ,
.Xr chroot 2 ,
.Xr getcap 3 ,
.Xr getttyent 3 ,
.Xr login_cap 3 ,
.Xr login_class 3 ,
.Xr pam 3 ,
.Xr passwd 5 ,
.Xr ttys 5 ,
.Xr ftpd 8 ,
.Xr pam_passwdqc 8
Reference in New Issue View Git Blame Copy Permalink