chpass/chpass.1

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