1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)passwd.1 8.1 (Berkeley) 6/6/93 29.\" $FreeBSD: src/usr.bin/passwd/passwd.1,v 1.33 2007/11/07 07:59:38 ru Exp $ 30.\" $DragonFly: src/usr.bin/passwd/passwd.1,v 1.6 2006/11/17 23:23:05 swildner Exp $ 31.\" 32.Dd June 6, 1993 33.Dt PASSWD 1 34.Os 35.Sh NAME 36.Nm passwd , 37.Nm yppasswd 38.Nd modify a user's password 39.Sh SYNOPSIS 40.Nm 41.Op Fl l 42.Op Ar user 43.Nm yppasswd 44.Op Fl l 45.Op Fl y 46.Op Fl d Ar domain 47.Op Fl h Ar host 48.Op Fl o 49.Sh DESCRIPTION 50The 51.Nm 52utility changes the user's local, Kerberos, or NIS password. 53If the user is not the super-user, 54.Nm 55first prompts for the current password and will not continue unless the correct 56password is entered. 57.Pp 58When entering the new password, the characters entered do not echo, in order to 59avoid the password being seen by a passer-by. 60The 61.Nm 62utility prompts for the new password twice in order to detect typing errors. 63.Pp 64The new password should be at least six characters long (which 65may be overridden using the 66.Xr login.conf 5 67.Dq minpasswordlen 68setting for a user's login class) and not purely alphabetic. 69Its total length must be less than 70.Dv _PASSWORD_LEN 71(currently 128 characters). 72.Pp 73The new password should contain a mixture of upper and lower case 74characters (which may be overridden using the 75.Xr login.conf 5 76.Dq mixpasswordcase 77setting for a user's login class). 78Allowing lower case passwords may 79be useful where the password file will be used in situations where only 80lower case passwords are permissible, such as when using Samba to 81authenticate Windows clients. 82In all other situations, numbers, upper 83case letters and meta characters are encouraged. 84.Pp 85Once the password has been verified, 86.Nm 87communicates the new password information to 88the Kerberos authenticating host. 89.Pp 90The following option is available: 91.Bl -tag -width indent 92.It Fl l 93Cause the password to be updated only in the local 94password file, and not with the Kerberos database. 95When changing only the local password, 96.Xr pwd_mkdb 8 97is used to update the password databases. 98.El 99.Pp 100When changing local or NIS password, the next password change date 101is set according to 102.Dq passwordtime 103capability in the user's login class. 104.Pp 105To change another user's Kerberos password, one must first 106run 107.Xr kinit 1 Pq Pa security/heimdal 108followed by 109.Nm . 110The super-user is not required to provide a user's current password 111if only the local password is modified. 112.Sh NIS INTERACTION 113The 114.Nm 115utility has built-in support for NIS. 116If a user exists in the NIS password 117database but does not exist locally, 118.Nm 119automatically switches into 120.Nm yppasswd 121mode. 122If the specified 123user does not exist in either the local password database or the 124NIS password maps, 125.Nm 126returns an error. 127.Pp 128When changing an NIS password, unprivileged users are required to provide 129their old password for authentication (the 130.Xr rpc.yppasswdd 8 131daemon requires the original password before 132it will allow any changes to the NIS password maps). 133This restriction applies even to the 134super-user, with one important exception: the password authentication is 135bypassed for the super-user on the NIS master server. 136This means that 137the super-user on the NIS master server can make unrestricted changes to 138anyone's NIS password. 139The super-user on NIS client systems and NIS slave 140servers still needs to provide a password before the update will be processed. 141.Pp 142The following additional options are supported for use with NIS: 143.Bl -tag -width indent 144.It Fl y 145Override 146.Nm Ns 's 147checking heuristics and forces 148it into NIS mode. 149.It Fl l 150When NIS is enabled, the 151.Fl l 152flag can be used to force 153.Nm 154into 155.Dq local only 156mode. 157This flag can be used to change the entry 158for a local user when an NIS user exists with the same login name. 159For example, you will sometimes find entries for system 160.Dq placeholder 161users such as 162.Pa bin 163or 164.Pa daemon 165in both the NIS password maps and the local user database. 166By 167default, 168.Nm 169will try to change the NIS password. 170The 171.Fl l 172flag can be used to change the local password instead. 173.It Fl d Ar domain 174Specify what domain to use when changing an NIS password. 175By default, 176.Nm 177assumes that the system default domain should be used. 178This flag is 179primarily for use by the superuser on the NIS master server: a single 180NIS server can support multiple domains. 181It is also possible that the 182domainname on the NIS master may not be set (it is not necessary for 183an NIS server to also be a client) in which case the 184.Nm 185command needs to be told what domain to operate on. 186.It Fl h Ar host 187Specify the name of an NIS server. 188This option, in conjunction 189with the 190.Fl d 191option, can be used to change an NIS password on a non-local NIS 192server. 193When a domain is specified with the 194.Fl d 195option and 196.Nm 197is unable to determine the name of the NIS master server (possibly because 198the local domainname is not set), the name of the NIS master is assumed to 199be 200.Dq localhost . 201This can be overridden with the 202.Fl h 203flag. 204The specified hostname need not be the name of an NIS master: the 205name of the NIS master for a given map can be determined by querying any 206NIS server (master or slave) in a domain, so specifying the name of a 207slave server will work equally well. 208.It Fl o 209Do not automatically override the password authentication checks for the 210super-user on the NIS master server; assume 211.Dq old 212mode instead. 213This 214flag is of limited practical use but is useful for testing. 215.El 216.Sh FILES 217.Bl -tag -width /etc/master.passwd -compact 218.It Pa /etc/master.passwd 219the user database 220.It Pa /etc/passwd 221a Version 7 format password file 222.It Pa /etc/passwd.XXXXXX 223temporary copy of the password file 224.It Pa /etc/login.conf 225login class capabilities database 226.It Pa /etc/auth.conf 227configure authentication services 228.El 229.Sh SEE ALSO 230.Xr chpass 1 , 231.Xr kinit 1 Pq Pa security/heimdal , 232.Xr login 1 , 233.Xr login.conf 5 , 234.Xr passwd 5 , 235.Xr kerberos 8 Pq Pa security/heimdal , 236.Xr kpasswdd 8 Pq Pa security/heimdal , 237.Xr pw 8 , 238.Xr pwd_mkdb 8 , 239.Xr vipw 8 240.Rs 241.%A Robert Morris 242.%A Ken Thompson 243.%T "UNIX password security" 244.Re 245.Sh NOTES 246The 247.Nm yppasswd 248command is really only a link to 249.Nm . 250.Sh HISTORY 251A 252.Nm 253command appeared in 254.At v6 . 255