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.
27 .Nd login class capability database
33 contains various attributes and capabilities of login classes.
34 A login class (an optional annotation against each record in the user
36 .Pa /etc/master.passwd )
37 determines session accounting, resource limits and user environment settings.
38 It is used by various programs in the system to set up a user's login
39 environment and to enforce policy, accounting and administrative restrictions.
40 It also provides the means by which users are able to be
41 authenticated to the system and the types of authentication available.
42 Attributes in addition to the ones described here are available with
45 A special record "default" in the system user class capability database
47 is used automatically for any
48 non-root user without a valid login class in
49 .Pa /etc/master.passwd .
50 A user with a uid of 0 without a valid login class will use the record
51 "root" if it exists, or "default" if not.
53 Users may individually create a file called
55 in their home directory using the same format, consisting of a single
56 entry with a record id of "me".
57 If present, this file is used by
59 to set user-defined environment settings which override those specified
60 in the system login capabilities database.
61 Only a subset of login capabilities may be overridden, typically those
62 which do not involve authentication, resource limits and accounting.
64 Records in a class capabilities database consist of a number of
65 colon-separated fields.
66 The first entry for each record gives one or more names that a record is
67 to be known by, each separated by a '|' character.
68 The first name is the most common abbreviation.
69 The last name given should be a long name that is more descriptive
70 of the capability entry, and all others are synonyms.
71 All names but the last should be in lower case and contain no blanks;
72 the last name may contain upper case characters and blanks for
75 Note that since a colon
77 is used to separate capability entries, a
79 escape sequence must be used to embed a literal colon in the
80 value or name of a capability.
86 is an out of the box configuration.
87 Whenever changes to this, or
90 file are made, the modifications will not be picked up until
92 is used to compile the file into a database.
93 This database file will have a
95 extension and is accessed through
99 for a more in-depth description of the format of a capability database.
101 Fields within each record in the database follow the
103 conventions for boolean, type string
107 although type numeric is deprecated in favour of the string format and
108 either form is accepted for a numeric datum.
109 Values fall into the following categories:
110 .Bl -tag -width "program"
112 If the name is present, then the boolean value is true; otherwise, it is
115 Path name to a data file
117 Path name to an executable file
119 A list of values (or pairs of values) separated by commas or spaces
121 A space or comma separated list of path names, following the usual csh
122 conventions (leading tilde with and without username being expanded to
123 home directories etc.)
125 A numeric value, either decimal (default), hexadecimal (with leading 0x),
126 or octal (with a leading 0).
127 With a numeric type, only one numeric value is allowed.
128 Numeric types may also be specified in string format (i.e., the capability
129 tag being delimited from the value by '=' instead of '#').
130 Whichever method is used, then all records in the database must use the
131 same method to allow values to be correctly overridden in interpolated
133 A numeric value may be infinite.
135 A number which expresses a size.
136 The default interpretation of a value is the number of bytes, but a
137 suffix may specify alternate units:
138 .Bl -tag -offset indent -compact -width xxxx
140 explicitly selects 512-byte blocks
142 selects kilobytes (1024 bytes)
144 specifies a multiplier of 1 megabyte (1048576 bytes),
146 specifies units of gigabytes, and
148 represents terabytes.
150 A size value is a numeric quantity and case of the suffix is not significant.
151 Concatenated values are added together.
152 A size value may be infinite.
154 A period of time, by default in seconds.
155 A prefix may specify a different unit:
156 .Bl -tag -offset indent -compact -width xxxx
158 indicates the number of 365 day years,
160 indicates the number of weeks,
166 the number of minutes, and
168 the number of seconds.
170 Concatenated values are added together.
171 For example, 2 hours and 40 minutes may be written either as
172 9600s, 160m or 2h40m.
173 A time value may be infinite.
181 are considered infinite values.
183 The usual convention to interpolate capability entries using the special
185 notation may be used.
187 .Bl -column pseudoterminals indent indent
188 .It Sy "Name Type Notes Description"
189 .It "coredumpsize size Maximum coredump size limit."
190 .It "cputime time CPU usage limit."
191 .It "datasize size Maximum data size limit."
192 .It "filesize size Maximum file size limit."
193 .It "maxproc number Maximum number of processes."
194 .It "memorylocked size Maximum locked in core memory size limit."
195 .It "memoryuse size Maximum of core memory use size limit."
196 .It "openfiles number Maximum number of open files per process."
197 .It "sbsize size Maximum permitted socketbuffer size."
198 .It "vmemoryuse size Maximum permitted total VM usage per process."
199 .It "stacksize size Maximum stack size limit."
200 .It "pseudoterminals number Maximum number of pseudo-terminals."
201 .It "swapuse size Maximum swap space size limit."
202 .It "umtxp number Maximum number of process-shared pthread locks."
205 These resource limit entries actually specify both the maximum
206 and current limits (see
208 The current (soft) limit is the one normally used, although the user is
209 permitted to increase the current limit to the maximum (hard) limit.
210 The maximum and current limits may be specified individually by appending a
211 -max or -cur to the capability name.
213 .Bl -column ignorenologin indent xbinxxusrxbin
214 .It Sy "Name Type Notes Description"
215 .It "charset string Set $MM_CHARSET environment variable to the specified"
217 .It "cpumask string List of cpus to bind the user to."
218 The syntax is the same as for the
227 .It "hushlogin bool false Same as having a ~/.hushlogin file."
228 .It "ignorenologin bool false Login not prevented by nologin."
229 .It "ftp-chroot bool false Limit FTP access with"
233 directory of the user.
237 .It "label string Default MAC policy; see"
239 .It "lang string Set $LANG environment variable to the specified value."
240 .It "mail string Set $MAIL environment variable to the specified value."
241 .It "manpath path Default search path for manpages."
242 .It "nocheckmail bool false Display mail status at login."
243 .It "nologin file If the file exists it will be displayed and"
244 the login session will be terminated.
245 .It "path path /bin /usr/bin Default search path."
246 .It "priority number Initial priority (nice) level."
247 .It "requirehome bool false Require a valid home directory to login."
248 .It "setenv list A comma-separated list of environment variables and"
249 values to which they are to be set.
250 Values containing commas must be quoted.
251 .It "shell prog Session shell to execute rather than the"
252 shell specified in the passwd file.
253 The SHELL environment variable will
254 contain the shell specified in the password file.
255 .It "term string Default terminal type if not able to determine"
257 .It "timezone string Default value of $TZ environment variable."
258 .It "umask number 022 Initial umask. Should always have a leading 0 to"
259 ensure octal interpretation.
260 .It "welcome file /etc/motd File containing welcome message."
263 .Bl -column passwd_prompt indent indent
264 .It Sy "Name Type Notes Description"
265 .\" .It "approve program Program to approve login.
266 .It "copyright file File containing additional copyright information"
267 .It "host.allow list List of remote host wildcards from which users in"
268 the class may access.
269 .It "host.deny list List of remote host wildcards from which users"
270 in the class may not access.
271 .It "login_prompt string The login prompt given by"
273 .It "login-backoff number 3 The number of login attempts"
274 allowed before the backoff delay is inserted after each subsequent
276 The backoff delay is the number of tries above
278 multiplied by 5 seconds.
279 .It "login-retries number 10 The number of login attempts"
280 allowed before the login fails.
281 .It "passwd_format string sha512 The encryption format that new or"
282 changed passwords will use.
283 Valid values include "des", "md5", "blf", "sha256" and "sha512"; see
288 NIS server should probably use "des".
289 .It "passwd_prompt string The password prompt presented by"
291 .It "passwordtime time Used by"
293 to set next password expiry date.
294 .It "times.allow list List of time periods during which"
296 .It "times.deny list List of time periods during which logins are"
298 .It "ttys.allow list List of ttys and ttygroups which users"
299 in the class may use for access.
300 .It "ttys.deny list List of ttys and ttygroups which users"
301 in the class may not use for access.
302 .It "warnexpire time Advance notice for pending account expiry."
303 .It "warnpassword time Advance notice for pending password expiry."
304 .\".It "widepasswords bool false Use the wide password format. The wide password
305 .\" format allows up to 128 significant characters in the password.
308 These fields are intended to be used by
310 and other programs in the login authentication system.
312 Capabilities that set environment variables are scanned for both
316 characters, which are substituted for a user's home directory and name
318 To pass these characters literally into the environment variable, escape
319 the character by preceding it with a backslash '\\'.
325 entries are comma separated lists used for checking remote access to the system,
326 and consist of a list of hostnames and/or IP addresses against which remote
327 network logins are checked.
328 Items in these lists may contain wildcards in the form used by shell programs
329 for wildcard matching (See
331 for details on the implementation).
332 The check on hosts is made against both the remote system's Internet address
333 and hostname (if available).
334 If both lists are empty or not specified, then logins from any remote host
336 If host.allow contains one or more hosts, then only remote systems matching
337 any of the items in that list are allowed to log in.
338 If host.deny contains one or more hosts, then a login from any matching hosts
345 entries consist of a comma-separated list of time periods during which the users
346 in a class are allowed to be logged in.
347 These are expressed as one or more day codes followed by a start and end times
348 expressed in 24 hour format, separated by a hyphen or dash.
349 For example, MoThSa0200-1300 translates to Monday, Thursday and Saturday between
350 the hours of 2 am and 1 p.m..
351 If both of these time lists are empty, users in the class are allowed access at
355 is specified, then logins are only allowed during the periods given.
358 is specified, then logins are denied during the periods given, regardless of whether
359 one of the periods specified in
365 enforces only that the actual login falls within periods allowed by these entries.
366 Further enforcement over the life of a session requires a separate daemon to
367 monitor transitions from an allowed period to a non-allowed one.
373 entries contain a comma-separated list of tty devices (without the /dev/ prefix)
374 that a user in a class may use to access the system, and/or a list of ttygroups
379 for information on ttygroups).
380 If neither entry exists, then the choice of login device used by the user is
384 is specified, then the user is restricted only to ttys in the given
385 group or device list.
388 is specified, then the user is prevented from using the specified devices or
389 devices in the group.
390 If both lists are given and are non-empty, the user is restricted to those
391 devices allowed by ttys.allow that are not available by ttys.deny.
397 facilities for enforcing restrictions on password quality, which used
400 have been superseded by the
403 .Sh RESERVED CAPABILITIES
404 The following capabilities are reserved for the purposes indicated and
405 may be supported by third-party software.
406 They are not implemented in the base system.
407 .Bl -column host.accounted indent indent
408 .It Sy "Name Type Notes Description"
409 .It "accounted bool false Enable session time accounting for all users"
411 .It "auth list passwd Allowed authentication styles."
412 The first item is the default style.
413 .It "auth-" Ns Ar type Ta "list Allowed authentication styles for the"
416 .It "autodelete time Time after expiry when account is auto-deleted."
417 .It "bootfull bool false Enable 'boot only if ttygroup is full' strategy"
418 when terminating sessions.
419 .It "daytime time Maximum login time per day."
420 .It "expireperiod time Time for expiry allocation."
421 .It "graceexpire time Grace days for expired account."
422 .It "gracetime time Additional grace login time allowed."
423 .It "host.accounted list List of remote host wildcards from which"
424 login sessions will be accounted.
425 .It "host.exempt list List of remote host wildcards from which"
426 login session accounting is exempted.
427 .It "idletime time Maximum idle time before logout."
428 .It "minpasswordlen number 6 The minimum length a local"
430 .It "mixpasswordcase bool true Whether"
432 will warn the user if an all lower case password is entered.
433 .It "monthtime time Maximum login time per month."
434 .It "refreshtime time New time allowed on account refresh."
435 .It "refreshperiod str How often account time is refreshed."
436 .It "sessiontime time Maximum login time per session."
437 .It "sessionlimit number Maximum number of concurrent"
438 login sessions on ttys in any group.
439 .It "ttys.accounted list List of ttys and ttygroups for which"
440 login accounting is active.
441 .It "ttys.exempt list List of ttys and ttygroups for which login accounting"
443 .It "warntime time Advance notice for pending out-of-time."
444 .It "weektime time Maximum login time per week."
451 fields operate in a similar manner to