1 .\" Copyright (c) 1996 David Nugent <davidn@blaze.net.au>
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, is permitted provided that the following conditions
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10 .\" 2. Redistributions in binary form must reproduce the above copyright
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13 .\" 3. This work was done expressly for inclusion into FreeBSD. Other use
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15 .\" 4. Absolutely no warranty of function or purpose is made by the author
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18 .\" conditions are met.
25 .Nd login class capability database
31 contains various attributes and capabilities of login classes.
32 A login class (an optional annotation against each record in the user
34 .Pa /etc/master.passwd )
35 determines session accounting, resource limits and user environment settings.
36 It is used by various programs in the system to set up a user's login
37 environment and to enforce policy, accounting and administrative restrictions.
38 It also provides the means by which users are able to be
39 authenticated to the system and the types of authentication available.
40 Attributes in addition to the ones described here are available with
43 A special record "default" in the system user class capability database
45 is used automatically for any
46 non-root user without a valid login class in
47 .Pa /etc/master.passwd .
48 A user with a uid of 0 without a valid login class will use the record
49 "root" if it exists, or "default" if not.
51 Users may individually create a file called
53 in their home directory using the same format, consisting of a single
54 entry with a record id of "me".
55 If present, this file is used by
57 to set user-defined environment settings which override those specified
58 in the system login capabilities database.
59 Only a subset of login capabilities may be overridden, typically those
60 which do not involve authentication, resource limits and accounting.
62 Records in a class capabilities database consist of a number of
63 colon-separated fields.
64 The first entry for each record gives one or more names that a record is
65 to be known by, each separated by a '|' character.
66 The first name is the most common abbreviation.
67 The last name given should be a long name that is more descriptive
68 of the capability entry, and all others are synonyms.
69 All names but the last should be in lower case and contain no blanks;
70 the last name may contain upper case characters and blanks for
73 Note that since a colon
75 is used to separate capability entries, a
77 escape sequence must be used to embed a literal colon in the
78 value or name of a capability.
84 is an out of the box configuration.
85 Whenever changes to this, or
88 file are made, the modifications will not be picked up until
90 is used to compile the file into a database.
91 This database file will have a
93 extension and is accessed through
97 for a more in-depth description of the format of a capability database.
99 Fields within each record in the database follow the
101 conventions for boolean, type string
105 although type numeric is deprecated in favour of the string format and
106 either form is accepted for a numeric datum.
107 Values fall into the following categories:
108 .Bl -tag -width "program"
110 If the name is present, then the boolean value is true; otherwise, it is
113 Path name to a data file
115 Path name to an executable file
117 A list of values (or pairs of values) separated by commas or spaces
119 A space or comma separated list of path names, following the usual csh
120 conventions (leading tilde with and without username being expanded to
121 home directories etc.)
123 A numeric value, either decimal (default), hexadecimal (with leading 0x),
124 or octal (with a leading 0).
125 With a numeric type, only one numeric value is allowed.
126 Numeric types may also be specified in string format (i.e., the capability
127 tag being delimited from the value by '=' instead of '#').
128 Whichever method is used, then all records in the database must use the
129 same method to allow values to be correctly overridden in interpolated
131 A numeric value may be infinite.
133 A number which expresses a size.
134 The default interpretation of a value is the number of bytes, but a
135 suffix may specify alternate units:
136 .Bl -tag -offset indent -compact -width xxxx
138 explicitly selects 512-byte blocks
140 selects kilobytes (1024 bytes)
142 specifies a multiplier of 1 megabyte (1048576 bytes),
144 specifies units of gigabytes, and
146 represents terabytes.
148 A size value is a numeric quantity and case of the suffix is not significant.
149 Concatenated values are added together.
150 A size value may be infinite.
152 A period of time, by default in seconds.
153 A prefix may specify a different unit:
154 .Bl -tag -offset indent -compact -width xxxx
156 indicates the number of 365 day years,
158 indicates the number of weeks,
164 the number of minutes, and
166 the number of seconds.
168 Concatenated values are added together.
169 For example, 2 hours and 40 minutes may be written either as
170 9600s, 160m or 2h40m.
171 A time value may be infinite.
179 are considered infinite values.
181 The usual convention to interpolate capability entries using the special
183 notation may be used.
185 .Bl -column pseudoterminals indent indent
186 .It Sy "Name Type Notes Description"
187 .It "coredumpsize size Maximum coredump size limit."
188 .It "cputime time CPU usage limit."
189 .It "datasize size Maximum data size limit."
190 .It "filesize size Maximum file size limit."
191 .It "maxproc number Maximum number of processes."
192 .It "memorylocked size Maximum locked in core memory size limit."
193 .It "memoryuse size Maximum of core memory use size limit."
194 .It "openfiles number Maximum number of open files per process."
195 .It "sbsize size Maximum permitted socketbuffer size."
196 .It "vmemoryuse size Maximum permitted total VM usage per process."
197 .It "stacksize size Maximum stack size limit."
198 .It "pseudoterminals number Maximum number of pseudo-terminals."
199 .It "swapuse size Maximum swap space size limit."
200 .It "umtxp number Maximum number of process-shared pthread locks."
203 These resource limit entries actually specify both the maximum
204 and current limits (see
206 The current (soft) limit is the one normally used, although the user is
207 permitted to increase the current limit to the maximum (hard) limit.
208 The maximum and current limits may be specified individually by appending a
209 -max or -cur to the capability name.
211 .Bl -column ignorenologin indent xbinxxusrxbin
212 .It Sy "Name Type Notes Description"
213 .It "charset string Set $MM_CHARSET environment variable to the specified"
215 .It "cpumask string List of cpus to bind the user to."
216 The syntax is the same as for the
225 .It "hushlogin bool false Same as having a ~/.hushlogin file."
226 .It "ignorenologin bool false Login not prevented by nologin."
227 .It "ftp-chroot bool false Limit FTP access with"
231 directory of the user.
235 .It "label string Default MAC policy; see"
237 .It "lang string Set $LANG environment variable to the specified value."
238 .It "mail string Set $MAIL environment variable to the specified value."
239 .It "manpath path Default search path for manpages."
240 .It "nocheckmail bool false Display mail status at login."
241 .It "nologin file If the file exists it will be displayed and"
242 the login session will be terminated.
243 .It "path path /bin /usr/bin Default search path."
244 .It "priority number Initial priority (nice) level."
245 .It "requirehome bool false Require a valid home directory to login."
246 .It "setenv list A comma-separated list of environment variables and"
247 values to which they are to be set.
248 Values containing commas must be quoted.
249 .It "shell prog Session shell to execute rather than the"
250 shell specified in the passwd file.
251 The SHELL environment variable will
252 contain the shell specified in the password file.
253 .It "term string Default terminal type if not able to determine"
255 .It "timezone string Default value of $TZ environment variable."
256 .It "umask number 022 Initial umask. Should always have a leading 0 to"
257 ensure octal interpretation.
258 .It "welcome file /etc/motd File containing welcome message."
261 .Bl -column passwd_prompt indent indent
262 .It Sy "Name Type Notes Description"
263 .\" .It "approve program Program to approve login.
264 .It "copyright file File containing additional copyright information"
265 .It "host.allow list List of remote host wildcards from which users in"
266 the class may access.
267 .It "host.deny list List of remote host wildcards from which users"
268 in the class may not access.
269 .It "login_prompt string The login prompt given by"
271 .It "login-backoff number 3 The number of login attempts"
272 allowed before the backoff delay is inserted after each subsequent
274 The backoff delay is the number of tries above
276 multiplied by 5 seconds.
277 .It "login-retries number 10 The number of login attempts"
278 allowed before the login fails.
279 .It "passwd_format string sha512 The encryption format that new or"
280 changed passwords will use.
281 Valid values include "des", "md5", "blf", "sha256" and "sha512"; see
286 NIS server should probably use "des".
287 .It "passwd_prompt string The password prompt presented by"
289 .It "passwordtime time Used by"
291 to set next password expiry date.
292 .It "times.allow list List of time periods during which"
294 .It "times.deny list List of time periods during which logins are"
296 .It "ttys.allow list List of ttys and ttygroups which users"
297 in the class may use for access.
298 .It "ttys.deny list List of ttys and ttygroups which users"
299 in the class may not use for access.
300 .It "warnexpire time Advance notice for pending account expiry."
301 .It "warnpassword time Advance notice for pending password expiry."
302 .\".It "widepasswords bool false Use the wide password format. The wide password
303 .\" format allows up to 128 significant characters in the password.
306 These fields are intended to be used by
308 and other programs in the login authentication system.
310 Capabilities that set environment variables are scanned for both
314 characters, which are substituted for a user's home directory and name
316 To pass these characters literally into the environment variable, escape
317 the character by preceding it with a backslash '\\'.
323 entries are comma separated lists used for checking remote access to the system,
324 and consist of a list of hostnames and/or IP addresses against which remote
325 network logins are checked.
326 Items in these lists may contain wildcards in the form used by shell programs
327 for wildcard matching (See
329 for details on the implementation).
330 The check on hosts is made against both the remote system's Internet address
331 and hostname (if available).
332 If both lists are empty or not specified, then logins from any remote host
334 If host.allow contains one or more hosts, then only remote systems matching
335 any of the items in that list are allowed to log in.
336 If host.deny contains one or more hosts, then a login from any matching hosts
343 entries consist of a comma-separated list of time periods during which the users
344 in a class are allowed to be logged in.
345 These are expressed as one or more day codes followed by a start and end times
346 expressed in 24 hour format, separated by a hyphen or dash.
347 For example, MoThSa0200-1300 translates to Monday, Thursday and Saturday between
348 the hours of 2 am and 1 p.m..
349 If both of these time lists are empty, users in the class are allowed access at
353 is specified, then logins are only allowed during the periods given.
356 is specified, then logins are denied during the periods given, regardless of whether
357 one of the periods specified in
363 enforces only that the actual login falls within periods allowed by these entries.
364 Further enforcement over the life of a session requires a separate daemon to
365 monitor transitions from an allowed period to a non-allowed one.
371 entries contain a comma-separated list of tty devices (without the /dev/ prefix)
372 that a user in a class may use to access the system, and/or a list of ttygroups
377 for information on ttygroups).
378 If neither entry exists, then the choice of login device used by the user is
382 is specified, then the user is restricted only to ttys in the given
383 group or device list.
386 is specified, then the user is prevented from using the specified devices or
387 devices in the group.
388 If both lists are given and are non-empty, the user is restricted to those
389 devices allowed by ttys.allow that are not available by ttys.deny.
395 facilities for enforcing restrictions on password quality, which used
398 have been superseded by the
401 .Sh RESERVED CAPABILITIES
402 The following capabilities are reserved for the purposes indicated and
403 may be supported by third-party software.
404 They are not implemented in the base system.
405 .Bl -column host.accounted indent indent
406 .It Sy "Name Type Notes Description"
407 .It "accounted bool false Enable session time accounting for all users"
409 .It "auth list passwd Allowed authentication styles."
410 The first item is the default style.
411 .It "auth-" Ns Ar type Ta "list Allowed authentication styles for the"
414 .It "autodelete time Time after expiry when account is auto-deleted."
415 .It "bootfull bool false Enable 'boot only if ttygroup is full' strategy"
416 when terminating sessions.
417 .It "daytime time Maximum login time per day."
418 .It "expireperiod time Time for expiry allocation."
419 .It "graceexpire time Grace days for expired account."
420 .It "gracetime time Additional grace login time allowed."
421 .It "host.accounted list List of remote host wildcards from which"
422 login sessions will be accounted.
423 .It "host.exempt list List of remote host wildcards from which"
424 login session accounting is exempted.
425 .It "idletime time Maximum idle time before logout."
426 .It "minpasswordlen number 6 The minimum length a local"
428 .It "mixpasswordcase bool true Whether"
430 will warn the user if an all lower case password is entered.
431 .It "monthtime time Maximum login time per month."
432 .It "refreshtime time New time allowed on account refresh."
433 .It "refreshperiod str How often account time is refreshed."
434 .It "sessiontime time Maximum login time per session."
435 .It "sessionlimit number Maximum number of concurrent"
436 login sessions on ttys in any group.
437 .It "ttys.accounted list List of ttys and ttygroups for which"
438 login accounting is active.
439 .It "ttys.exempt list List of ttys and ttygroups for which login accounting"
441 .It "warntime time Advance notice for pending out-of-time."
442 .It "weektime time Maximum login time per week."
449 fields operate in a similar manner to