chpass/chpass.1

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  32 .\"     @(#)chpass.1    8.2 (Berkeley) 12/30/93
  33 .\"     $Id: chpass.1,v 1.14 1998/12/13 15:32:26 bde Exp $
  34 .\"
  35 .Dd December 30, 1993
  36 .Dt CHPASS 1
  37 .Os
  38 .Sh NAME
  39 .Nm chpass, chfn, chsh, ypchpass, ypchfn, ypchsh
  40 .Nd add or change user database information
  41 .Sh SYNOPSIS
  42 .Nm chpass
  43 .Op Fl a Ar list
  44 .Op Fl p Ar encpass
  45 .Op Fl s Ar newshell
  46 .Op user
  47 .Sh DESCRIPTION
  48 The
  49 .Nm chpass
  50 program
  51 allows editing of the user database information associated
  52 with
  53 .Ar user
  54 or, by default, the current user.
  55 The information is formatted and supplied to an editor for changes.
  56 .Pp
  57 Only the information that the user is allowed to change is displayed.
  58 .Pp
  59 The options are as follows:
  60 .Bl -tag -width flag
  61 .It Fl a
  62 The super-user is allowed to directly supply a user database
  63 entry, in the format specified by
  64 .Xr passwd 5 ,
  65 as an argument.
  66 This argument must be a colon (``:'') separated list of all the
  67 user database fields, although they may be empty.
  68 .It Fl p
  69 The super-user is allowed to directly supply an encrypted password field,
  70 in the format used by
  71 .Xr crypt 3 ,
  72 as an argument.
  73 .It Fl s
  74 The
  75 .Fl s
  76 option attempts to change the user's shell to
  77 .Ar newshell .
  78 .El
  79 .Pp
  80 Possible display items are as follows:
  81 .Pp
  82 .Bl -tag -width "Other Information:" -compact -offset indent
  83 .It Login:
  84 user's login name
  85 .It Password:
  86 user's encrypted password
  87 .It Uid:
  88 user's login
  89 .It Gid:
  90 user's login group
  91 .It Class:
  92 user's general classification
  93 .It Change:
  94 password change time
  95 .It Expire:
  96 account expiration time
  97 .It Full Name:
  98 user's real name
  99 .It Office Location:
 100 user's office location (1)
 101 .It Office Phone:
 102 user's office phone (1)
 103 .It Home Phone:
 104 user's home phone (1)
 105 .It Other Information:
 106 any locally defined parameters for user (1)
 107 .It Home Directory:
 108 user's home directory
 109 .It Shell:
 110 user's login shell
 111 .Pp
 112 .It NOTE(1) -
 113 In the actual master.passwd file, these fields are comma-delimited
 114 fields embedded in the FullName field.
 115 .El
 116 .Pp
 117 The
 118 .Ar login
 119 field is the user name used to access the computer account.
 120 .Pp
 121 The
 122 .Ar password
 123 field contains the encrypted form of the user's password.
 124 .Pp
 125 The
 126 .Ar uid
 127 field is the number associated with the
 128 .Ar login
 129 field.
 130 Both of these fields should be unique across the system (and often
 131 across a group of systems) as they control file access.
 132 .Pp
 133 While it is possible to have multiple entries with identical login names
 134 and/or identical user id's, it is usually a mistake to do so.  Routines
 135 that manipulate these files will often return only one of the multiple
 136 entries, and that one by random selection.
 137 .Pp
 138 The
 139 .Ar group
 140 field is the group that the user will be placed in at login.
 141 Since BSD supports multiple groups (see
 142 .Xr groups 1 )
 143 this field currently has little special meaning.
 144 This field may be filled in with either a number or a group name (see
 145 .Xr group 5 ) .
 146 .Pp
 147 The
 148 .Ar class
 149 field references class descriptions in
 150 .Ar /etc/login.conf
 151 and is typically used to initialize the user's system resource limits
 152 when they login.
 153 .Pp
 154 The
 155 .Ar change
 156 field is the date by which the password must be changed.
 157 .Pp
 158 The
 159 .Ar expire
 160 field is the date on which the account expires.
 161 .Pp
 162 Both the
 163 .Ar change
 164 and
 165 .Ar expire
 166 fields should be entered in the form ``month day year'' where
 167 .Ar month
 168 is the month name (the first three characters are sufficient),
 169 .Ar day
 170 is the day of the month, and
 171 .Ar year
 172 is the year.
 173 .Pp
 174 Five fields are available for storing the user's
 175 .Ar full name , office location ,
 176 .Ar work
 177 and
 178 .Ar home telephone
 179 numbers and finally
 180 .Ar other information
 181 which is a single comma delimited string to represent any additional
 182 gcos fields (typically used for site specific user information).
 183 Note that
 184 .Xr finger 1
 185 will display the office location and office phone together under the
 186 heading
 187 .Ar Office: .
 188 .Pp
 189 The user's
 190 .Ar home directory
 191 is the full UNIX path name where the user
 192 will be placed at login.
 193 .Pp
 194 The
 195 .Ar shell
 196 field is the command interpreter the user prefers.
 197 If the
 198 .Ar shell
 199 field is empty, the Bourne shell,
 200 .Pa /bin/sh ,
 201 is assumed.
 202 When altering a login shell, and not the super-user, the user
 203 may not change from a non-standard shell or to a non-standard
 204 shell.
 205 Non-standard is defined as a shell not found in
 206 .Pa /etc/shells .
 207 .Pp
 208 Once the information has been verified,
 209 .Nm chpass
 210 uses
 211 .Xr pwd_mkdb 8
 212 to update the user database.
 213 .Sh ENVIRONMENT
 214 The
 215 .Xr vi 1
 216 editor will be used unless the environment variable EDITOR is set to
 217 an alternate editor.
 218 When the editor terminates, the information is re-read and used to
 219 update the user database itself.
 220 Only the user, or the super-user, may edit the information associated
 221 with the user.
 222 .Sh NIS INTERACTION
 223 .Nm Chpass
 224 can also be used in conjunction with NIS, however some restrictions
 225 apply.
 226 Currently,
 227 .Nm chpass
 228 can only make changes to the NIS passwd maps through
 229 .Xr rpc.yppasswdd 8 ,
 230 which normally only permits changes to a user's password, shell and GECOS
 231 fields. Except when invoked by the super-user on the NIS master server,
 232 .Nm chpass
 233 (and, similarly,
 234 .Xr passwd 1 )
 235 can not use the
 236 .Xr rpc.yppasswdd 8
 237 server to change other user information or
 238 add new records to the NIS passwd maps.
 239 Furthermore,
 240 .Xr rpc.yppasswdd 8
 241 requires password authentication before it will make any
 242 changes. The only user allowed to submit changes without supplying
 243 a password is the super-user on the NIS master server; all other users,
 244 including those with root privileges on NIS clients (and NIS slave
 245 servers) must enter a password.
 246 (The super-user on the NIS master is allowed to bypass these restrictions
 247 largely for convenience: a user with root access
 248 to the NIS master server already has the privileges required to make
 249 updates to the NIS maps, but editing the map source files by hand can
 250 be cumbersome.
 251 .Pp
 252 Note: these exceptions only apply when the NIS master server is a
 253 FreeBSD system.)
 254 .Pp
 255 Consequently, except where noted, the following restrictions apply when
 256 .Nm chpass
 257 is used with NIS:
 258 .Bl -enum -offset indent
 259 .It
 260 .Pa Only the shell and GECOS information may be changed.
 261 All other
 262 fields are restricted, even when
 263 .Nm chpass
 264 is invoked by the super-user.
 265 While support for
 266 changing other fields could be added, this would lead to
 267 compatibility problems with other NIS-capable systems.
 268 Even though the super-user may supply data for other fields
 269 while editing an entry, the extra information (other than the
 270 password -- see below) will be silently discarded.
 271 .Pp
 272 Exception: the super-user on the NIS master server is permitted to
 273 change any field.
 274 .Pp
 275 .It
 276 .Pa Password authentication is required.
 277 .Nm Chpass
 278 will prompt for the user's NIS password before effecting
 279 any changes. If the password is invalid, all changes will be
 280 discarded.
 281 .Pp
 282 Exception: the super-user on the NIS master server is allowed to
 283 submit changes without supplying a password. (The super-user may
 284 choose to turn off this feature using the
 285 .Fl o
 286 flag, described below.)
 287 .It
 288 .Pa Adding new records to the local
 289 .Pa password database is discouraged.
 290 .Nm Chpass
 291 will allow the administrator to add new records to the
 292 local password database while NIS is enabled, but this can lead to
 293 some confusion since the new records are appended to the end of
 294 the master password file, usually after the special NIS '+' entries.
 295 The administrator should use
 296 .Xr vipw 8
 297 to modify the local password
 298 file when NIS is running.
 299 .Pp
 300 The super-user on the NIS master server is permitted to add new records
 301 to the NIS password maps, provided the
 302 .Xr rpc.yppasswdd 8
 303 server has been started with the
 304 .Fl a
 305 flag to permitted additions (it refuses them by default).
 306 .Nm Chpass
 307 tries to update the local password database by default; to update the
 308 NIS maps instead, invoke chpass with the
 309 .Fl y
 310 flag.
 311 .It
 312 .Pa Password changes are not permitted.
 313 Users should use
 314 .Xr passwd 1
 315 or
 316 .Xr yppasswd 1
 317 to change their NIS passwords. The super-user is allowed to specify
 318 a new password (even though the ``Password:'' field does not show
 319 up in the editor template, the super-user may add it back by hand),
 320 but even the super-user must supply the user's original password
 321 otherwise
 322 .Xr rpc.yppasswdd 8
 323 will refuse to update the NIS maps.
 324 .Pp
 325 Exception: the super-user on the NIS master server is permitted to
 326 change a user's NIS password with
 327 .Nm chpass .
 328 .El
 329 .Pp
 330 There are also a few extra option flags that are available when
 331 .Nm chpass
 332 is compiled with NIS support:
 333 .Bl -tag -width flag
 334 .It Fl l
 335 The
 336 .Fl l
 337 flag forces
 338 .Nm chpass
 339 to modify the local copy of a user's password
 340 information in the even that a user exists in both
 341 the local and NIS databases.
 342 .It Fl y
 343 This flag has the opposite effect of
 344 .Fl l .
 345 This flag is largely redundant since
 346 .Nm chpass
 347 operates on NIS entries by default if NIS is enabled.
 348 .It Fl d Ar domain
 349 Specify a particular NIS domain.
 350 .Nm Chpass
 351 uses the system domain name by default, as set by the
 352 .Xr domainname 1
 353 command. The
 354 .Fl d
 355 option can be used to override a default, or to specify a domain
 356 when the system domain name is not set.
 357 .It Fl h Ar host
 358 Specify the name or address of an NIS server to query. Normally,
 359 .Nm chpass
 360 will communicate with the NIS master host specified in the
 361 .Pa master.passwd
 362 or
 363 .Pa passwd
 364 maps. On hosts that have not been configured as NIS clients, there is
 365 no way for the program to determine this information unless the user
 366 provides the hostname of a server. Note that the specified hostname need
 367 not be that of the NIS master server; the name of any server, master or
 368 slave, in a given NIS domain will do.
 369 .Pp
 370 When using the
 371 .Fl d
 372 option, the hostname defaults to ``localhost.'' The
 373 .Fl h
 374 option can be used in conjunction with the
 375 .Fl d
 376 option, in which case the user-specified hostname will override
 377 the default.
 378 .Pp
 379 .It Fl o
 380 Force the use of RPC-based updates when communicating with
 381 .Xr rpc.yppasswdd 8
 382 (``old-mode'').
 383 When invoked by the super-user on the NIS master server,
 384 .Nm chpass
 385 allows unrestricted changes to the NIS passwd maps using dedicated,
 386 non-RPC-based mechanism (in this case, a UNIX domain socket). The
 387 .Fl o
 388 flag can be used to force
 389 .Nm chpass
 390 to use the standard update mechanism instead. This option is provided
 391 mainly for testing purposes.
 392 .El
 393 .Pp
 394 .Sh FILES
 395 .Bl -tag -width /etc/master.passwd -compact
 396 .It Pa /etc/master.passwd
 397 The user database
 398 .It Pa /etc/passwd
 399 A Version 7 format password file
 400 .It Pa /etc/chpass.XXXXXX
 401 Temporary copy of the password file
 402 .It Pa /etc/shells
 403 The list of approved shells
 404 .El
 405 .Sh SEE ALSO
 406 .Xr finger 1 ,
 407 .Xr login 1 ,
 408 .Xr passwd 1 ,
 409 .Xr getusershell 3 ,
 410 .Xr login.conf 5,
 411 .Xr passwd 5 ,
 412 .Xr pwd_mkdb 8 ,
 413 .Xr vipw 8
 414 .Rs
 415 .%A Robert Morris
 416 and
 417 .%A Ken Thompson
 418 .%T "UNIX Password security"
 419 .Re
 420 .Sh NOTES
 421 The
 422 .Xr chfn 1 ,
 423 .Xr chsh 1 ,
 424 .Xr ypchpass 1 ,
 425 .Xr ypchfn 1
 426 and
 427 .Xr ypchsh 1
 428 commands are really only links to
 429 .Nm chpass .
 430 .Sh BUGS
 431 User information should (and eventually will) be stored elsewhere.
 432 .Sh HISTORY
 433 The
 434 .Nm
 435 command appeared in
 436 .Bx 4.3 Reno .