chpass/chpass.1

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  28 .\"     @(#)chpass.1    8.2 (Berkeley) 12/30/93
  29 .\" $FreeBSD$
  30 .\"
  31 .Dd November 17, 2020
  32 .Dt CHPASS 1
  33 .Os
  34 .Sh NAME
  35 .Nm chpass ,
  36 .Nm chfn ,
  37 .Nm chsh ,
  38 .Nm ypchpass ,
  39 .Nm ypchfn ,
  40 .Nm ypchsh
  41 .Nd add or change user database information
  42 .Sh SYNOPSIS
  43 .Nm
  44 .Op Fl loy
  45 .Op Fl a Ar list
  46 .Op Fl d Ar domain
  47 .Op Fl e Ar expiretime
  48 .Op Fl h Ar host
  49 .Op Fl p Ar encpass
  50 .Op Fl s Ar newshell
  51 .Op user
  52 .Sh DESCRIPTION
  53 The
  54 .Nm
  55 utility
  56 allows editing of the user database information associated
  57 with
  58 .Ar user
  59 or, by default, the current user.
  60 .Pp
  61 The
  62 .Nm chfn ,
  63 .Nm chsh ,
  64 .Nm ypchpass ,
  65 .Nm ypchfn
  66 and
  67 .Nm ypchsh
  68 utilities behave identically to
  69 .Nm .
  70 (There is only one program.)
  71 .Pp
  72 The information is formatted and supplied to an editor for changes.
  73 .Pp
  74 Only the information that the user is allowed to change is displayed.
  75 .Pp
  76 The options are as follows:
  77 .Bl -tag -width "-e expiretime"
  78 .It Fl a Ar list
  79 The super-user is allowed to directly supply a user database
  80 entry, in the format specified by
  81 .Xr passwd 5 ,
  82 as an argument.
  83 This argument must be a colon
  84 .Pq Dq \&:
  85 separated list of all the
  86 user database fields, although they may be empty.
  87 .It Fl e Ar expiretime
  88 Change the account expire time.
  89 This option is used to set the expire time
  90 from a script as if it was done in the interactive editor.
  91 .It Fl p Ar encpass
  92 The super-user is allowed to directly supply an encrypted password field,
  93 in the format used by
  94 .Xr crypt 3 ,
  95 as an argument.
  96 .It Fl s Ar newshell
  97 Attempt to change the user's shell to
  98 .Ar newshell .
  99 .El
 100 .Pp
 101 Possible display items are as follows:
 102 .Pp
 103 .Bl -tag -width "Other Information:" -compact -offset indent
 104 .It Login:
 105 user's login name
 106 .It Password:
 107 user's encrypted password
 108 .It Uid:
 109 user's login
 110 .It Gid:
 111 user's login group
 112 .It Class:
 113 user's general classification
 114 .It Change:
 115 password change time
 116 .It Expire:
 117 account expiration time
 118 .It Full Name:
 119 user's real name
 120 .It Office Location:
 121 user's office location (1)
 122 .It Office Phone:
 123 user's office phone (1)
 124 .It Home Phone:
 125 user's home phone (1)
 126 .It Other Information:
 127 any locally defined parameters for user (1)
 128 .It Home Directory:
 129 user's home directory
 130 .It Shell:
 131 user's login shell
 132 .Pp
 133 .It NOTE(1) -
 134 In the actual master.passwd file, these fields are comma-delimited
 135 fields embedded in the FullName field.
 136 .El
 137 .Pp
 138 The
 139 .Ar login
 140 field is the user name used to access the computer account.
 141 .Pp
 142 The
 143 .Ar password
 144 field contains the encrypted form of the user's password.
 145 .Pp
 146 The
 147 .Ar uid
 148 field is the number associated with the
 149 .Ar login
 150 field.
 151 Both of these fields should be unique across the system (and often
 152 across a group of systems) as they control file access.
 153 .Pp
 154 While it is possible to have multiple entries with identical login names
 155 and/or identical user id's, it is usually a mistake to do so.
 156 Routines
 157 that manipulate these files will often return only one of the multiple
 158 entries, and that one by random selection.
 159 .Pp
 160 The
 161 .Ar gid
 162 field is the group that the user will be placed in at login.
 163 Since
 164 .Bx
 165 supports multiple groups (see
 166 .Xr groups 1 )
 167 this field currently has little special meaning.
 168 This field may be filled in with either a number or a group name (see
 169 .Xr group 5 ) .
 170 .Pp
 171 The
 172 .Ar class
 173 field references class descriptions in
 174 .Pa /etc/login.conf
 175 and is typically used to initialize the user's system resource limits
 176 when they login.
 177 .Pp
 178 The
 179 .Ar change
 180 field is the date by which the password must be changed.
 181 .Pp
 182 The
 183 .Ar expire
 184 field is the date on which the account expires.
 185 .Pp
 186 Both the
 187 .Ar change
 188 and
 189 .Ar expire
 190 fields should be entered in the form
 191 .Dq month day year
 192 where
 193 .Ar month
 194 is the month name (the first three characters are sufficient),
 195 .Ar day
 196 is the day of the month, and
 197 .Ar year
 198 is the year.
 199 .Pp
 200 Five fields are available for storing the user's
 201 .Ar full name , office location ,
 202 .Ar work
 203 and
 204 .Ar home telephone
 205 numbers and finally
 206 .Ar other information
 207 which is a single comma delimited string to represent any additional
 208 gecos fields (typically used for site specific user information).
 209 Note that
 210 .Xr finger 1
 211 will display the office location and office phone together under the
 212 heading
 213 .Ar Office\&: .
 214 .Pp
 215 The user's
 216 .Ar home directory
 217 is the full
 218 .Ux
 219 path name where the user
 220 will be placed at login.
 221 .Pp
 222 The
 223 .Ar shell
 224 field is the command interpreter the user prefers.
 225 If the
 226 .Ar shell
 227 field is empty, the Bourne shell,
 228 .Pa /bin/sh ,
 229 is assumed.
 230 When altering a login shell, and not the super-user, the user
 231 may not change from a non-standard shell or to a non-standard
 232 shell.
 233 Non-standard is defined as a shell not found in
 234 .Pa /etc/shells .
 235 .Pp
 236 Once the information has been verified,
 237 .Nm
 238 uses
 239 .Xr pwd_mkdb 8
 240 to update the user database.
 241 .Sh ENVIRONMENT
 242 The
 243 .Xr vi 1
 244 editor will be used unless the environment variable
 245 .Ev EDITOR
 246 is set to
 247 an alternate editor.
 248 When the editor terminates, the information is re-read and used to
 249 update the user database itself.
 250 Only the user, or the super-user, may edit the information associated
 251 with the user.
 252 .Pp
 253 See
 254 .Xr pwd_mkdb 8
 255 for an explanation of the impact of setting the
 256 .Ev PW_SCAN_BIG_IDS
 257 environment variable.
 258 .Sh NIS INTERACTION
 259 The
 260 .Nm
 261 utility can also be used in conjunction with NIS, however some restrictions
 262 apply.
 263 Currently,
 264 .Nm
 265 can only make changes to the NIS passwd maps through
 266 .Xr rpc.yppasswdd 8 ,
 267 which normally only permits changes to a user's password, shell and GECOS
 268 fields.
 269 Except when invoked by the super-user on the NIS master server,
 270 .Nm
 271 (and, similarly,
 272 .Xr passwd 1 )
 273 cannot use the
 274 .Xr rpc.yppasswdd 8
 275 server to change other user information or
 276 add new records to the NIS passwd maps.
 277 Furthermore,
 278 .Xr rpc.yppasswdd 8
 279 requires password authentication before it will make any
 280 changes.
 281 The only user allowed to submit changes without supplying
 282 a password is the super-user on the NIS master server; all other users,
 283 including those with root privileges on NIS clients (and NIS slave
 284 servers) must enter a password.
 285 (The super-user on the NIS master is allowed to bypass these restrictions
 286 largely for convenience: a user with root access
 287 to the NIS master server already has the privileges required to make
 288 updates to the NIS maps, but editing the map source files by hand can
 289 be cumbersome.
 290 .Pp
 291 Note: these exceptions only apply when the NIS master server is a
 292 .Fx
 293 system).
 294 .Pp
 295 Consequently, except where noted, the following restrictions apply when
 296 .Nm
 297 is used with NIS:
 298 .Bl -enum -offset indent
 299 .It
 300 .Em "Only the shell and GECOS information may be changed" .
 301 All other
 302 fields are restricted, even when
 303 .Nm
 304 is invoked by the super-user.
 305 While support for
 306 changing other fields could be added, this would lead to
 307 compatibility problems with other NIS-capable systems.
 308 Even though the super-user may supply data for other fields
 309 while editing an entry, the extra information (other than the
 310 password \(em see below) will be silently discarded.
 311 .Pp
 312 Exception: the super-user on the NIS master server is permitted to
 313 change any field.
 314 .It
 315 .Em "Password authentication is required" .
 316 The
 317 .Nm
 318 utility will prompt for the user's NIS password before effecting
 319 any changes.
 320 If the password is invalid, all changes will be
 321 discarded.
 322 .Pp
 323 Exception: the super-user on the NIS master server is allowed to
 324 submit changes without supplying a password.
 325 (The super-user may
 326 choose to turn off this feature using the
 327 .Fl o
 328 flag, described below.)
 329 .It
 330 .Em "Adding new records to the local password database is discouraged" .
 331 The
 332 .Nm
 333 utility will allow the administrator to add new records to the
 334 local password database while NIS is enabled, but this can lead to
 335 some confusion since the new records are appended to the end of
 336 the master password file, usually after the special NIS '+' entries.
 337 The administrator should use
 338 .Xr vipw 8
 339 to modify the local password
 340 file when NIS is running.
 341 .Pp
 342 The super-user on the NIS master server is permitted to add new records
 343 to the NIS password maps, provided the
 344 .Xr rpc.yppasswdd 8
 345 server has been started with the
 346 .Fl a
 347 flag to permitted additions (it refuses them by default).
 348 The
 349 .Nm
 350 utility tries to update the local password database by default; to update the
 351 NIS maps instead, invoke chpass with the
 352 .Fl y
 353 flag.
 354 .It
 355 .Em "Password changes are not permitted".
 356 Users should use
 357 .Xr passwd 1
 358 or
 359 .Xr yppasswd 1
 360 to change their NIS passwords.
 361 The super-user is allowed to specify
 362 a new password (even though the
 363 .Dq Password:
 364 field does not show
 365 up in the editor template, the super-user may add it back by hand),
 366 but even the super-user must supply the user's original password
 367 otherwise
 368 .Xr rpc.yppasswdd 8
 369 will refuse to update the NIS maps.
 370 .Pp
 371 Exception: the super-user on the NIS master server is permitted to
 372 change a user's NIS password with
 373 .Nm .
 374 .El
 375 .Pp
 376 There are also a few extra option flags that are available when
 377 .Nm
 378 is compiled with NIS support:
 379 .Bl -tag -width "-d domain"
 380 .It Fl d Ar domain
 381 Specify a particular NIS domain.
 382 The
 383 .Nm
 384 utility uses the system domain name by default, as set by the
 385 .Xr domainname 1
 386 utility.
 387 The
 388 .Fl d
 389 option can be used to override a default, or to specify a domain
 390 when the system domain name is not set.
 391 .It Fl h Ar host
 392 Specify the name or address of an NIS server to query.
 393 Normally,
 394 .Nm
 395 will communicate with the NIS master host specified in the
 396 .Pa master.passwd
 397 or
 398 .Pa passwd
 399 maps.
 400 On hosts that have not been configured as NIS clients, there is
 401 no way for the program to determine this information unless the user
 402 provides the hostname of a server.
 403 Note that the specified hostname need
 404 not be that of the NIS master server; the name of any server, master or
 405 slave, in a given NIS domain will do.
 406 .Pp
 407 When using the
 408 .Fl d
 409 option, the hostname defaults to
 410 .Dq localhost .
 411 The
 412 .Fl h
 413 option can be used in conjunction with the
 414 .Fl d
 415 option, in which case the user-specified hostname will override
 416 the default.
 417 .It Fl l
 418 Force
 419 .Nm
 420 to modify the local copy of a user's password
 421 information in the event that a user exists in both
 422 the local and NIS databases.
 423 .It Fl o
 424 Force the use of RPC-based updates when communicating with
 425 .Xr rpc.yppasswdd 8
 426 .Pq Dq old-mode .
 427 When invoked by the super-user on the NIS master server,
 428 .Nm
 429 allows unrestricted changes to the NIS passwd maps using dedicated,
 430 non-RPC-based mechanism (in this case, a
 431 .Ux
 432 domain socket).
 433 The
 434 .Fl o
 435 flag can be used to force
 436 .Nm
 437 to use the standard update mechanism instead.
 438 This option is provided
 439 mainly for testing purposes.
 440 .It Fl y
 441 Opposite effect of
 442 .Fl l .
 443 This flag is largely redundant since
 444 .Nm
 445 operates on NIS entries by default if NIS is enabled.
 446 .El
 447 .Sh FILES
 448 .Bl -tag -width /etc/master.passwd -compact
 449 .It Pa /etc/master.passwd
 450 the user database
 451 .It Pa /etc/passwd
 452 a Version 7 format password file
 453 .It Pa /etc/chpass.XXXXXX
 454 temporary copy of the password file
 455 .It Pa /etc/shells
 456 the list of approved shells
 457 .El
 458 .Sh SEE ALSO
 459 .Xr finger 1 ,
 460 .Xr login 1 ,
 461 .Xr passwd 1 ,
 462 .Xr getusershell 3 ,
 463 .Xr login.conf 5 ,
 464 .Xr passwd 5 ,
 465 .Xr pw 8 ,
 466 .Xr pwd_mkdb 8 ,
 467 .Xr vipw 8
 468 .Rs
 469 .%A Robert Morris
 470 .%A Ken Thompson
 471 .%T "UNIX Password security"
 472 .Re
 473 .Sh HISTORY
 474 The
 475 .Nm
 476 utility appeared in
 477 .Bx 4.3 Reno .
 478 .Sh BUGS
 479 User information should (and eventually will) be stored elsewhere.