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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)passwd.1 8.1 (Berkeley) 6/6/93 33.\" $FreeBSD: src/usr.bin/passwd/passwd.1,v 1.18.2.5 2002/06/21 15:28:37 charnier Exp $ 34.\" $DragonFly: src/usr.bin/passwd/passwd.1,v 1.3 2004/07/16 00:45:34 hmp Exp $ 35.\" 36.Dd June 6, 1993 37.Dt PASSWD 1 38.Os 39.Sh NAME 40.Nm passwd , yppasswd 41.Nd modify a user's password 42.Sh SYNOPSIS 43.Nm 44.Op Fl l 45.Op Ar user 46.Nm yppasswd 47.Op Fl l 48.Op Fl y 49.Op Fl d Ar domain 50.Op Fl h Ar host 51.Op Fl o 52.Sh DESCRIPTION 53The 54.Nm 55utility changes the user's local, Kerberos, or NIS password. 56If the user is not the super-user, 57.Nm 58first prompts for the current password and will not continue unless the correct 59password is entered. 60.Pp 61When entering the new password, the characters entered do not echo, in order to 62avoid the password being seen by a passer-by. 63The 64.Nm 65utility prompts for the new password twice in order to detect typing errors. 66.Pp 67The new password should be at least six characters long (which 68may be overridden using the 69.Xr login.conf 5 70.Dq minpasswordlen 71setting for a user's login class) and not purely alphabetic. 72Its total length must be less than 73.Dv _PASSWORD_LEN 74(currently 128 characters). 75.Pp 76The new password should contain a mixture of upper and lower case 77characters (which may be overridden using the 78.Xr login.conf 5 79.Dq mixpasswordcase 80setting for a user's login class). 81Allowing lower case passwords may 82be useful where the password file will be used in situations where only 83lower case passwords are permissible, such as when using Samba to 84authenticate Windows clients. 85In all other situations, numbers, upper 86case letters and meta characters are encouraged. 87.Pp 88Once the password has been verified, 89.Nm 90communicates the new password information to 91the Kerberos authenticating host. 92.Bl -tag -width flag 93.It Fl l 94This option causes the password to be updated only in the local 95password file, and not with the Kerberos database. 96When changing only the local password, 97.Xr pwd_mkdb 8 98is used to update the password databases. 99.Pp 100.El 101When changing local or NIS password, the next password change date 102is set according to 103.Dq passwordtime 104capability in the user's login class. 105.Pp 106To change another user's Kerberos password, one must first 107run 108.Xr kinit 1 109followed by 110.Xr passwd 1 . 111The super-user is not required to provide a user's current password 112if only the local password is modified. 113.Sh NIS INTERACTION 114The 115.Nm 116utility has built-in support for NIS. 117If a user exists in the NIS password 118database but does not exist locally, 119.Nm 120automatically switches into 121.Dq yppasswd 122mode. 123If the specified 124user does not exist in either the local password database of the 125NIS password maps, 126.Nm 127returns an error. 128.Pp 129When changing an NIS password, unprivileged users are required to provide 130their old password for authentication (the 131.Xr rpc.yppasswdd 8 132daemon requires the original password before 133it will allow any changes to the NIS password maps). 134This restriction applies even to the 135super-user, with one important exception: the password authentication is 136bypassed for the super-user on the NIS master server. 137This means that 138the super-user on the NIS master server can make unrestricted changes to 139anyone's NIS password. 140The super-user on NIS client systems and NIS slave 141servers still needs to provide a password before the update will be processed. 142.Pp 143The following additional options are supported for use with NIS: 144.Bl -tag -width flag 145.It Fl y 146The 147.Fl y 148flag overrides 149.Nm Ns 's 150checking heuristics and forces 151it into NIS mode. 152.It Fl l 153When NIS is enabled, the 154.Fl l 155flag can be used to force 156.Nm 157into 158.Dq local only 159mode. 160This flag can be used to change the entry 161for a local user when an NIS user exists with the same login name. 162For example, you will sometimes find entries for system 163.Dq placeholder 164users such as 165.Pa bin 166or 167.Pa daemon 168in both the NIS password maps and the local user database. 169By 170default, 171.Nm 172will try to change the NIS password. 173The 174.Fl l 175flag can be used to change the local password instead. 176.It Fl d Ar domain 177Specify what domain to use when changing an NIS password. 178By default, 179.Nm 180assumes that the system default domain should be used. 181This flag is 182primarily for use by the superuser on the NIS master server: a single 183NIS server can support multiple domains. 184It is also possible that the 185domainname on the NIS master may not be set (it is not necessary for 186an NIS server to also be a client) in which case the 187.Nm 188command needs to be told what domain to operate on. 189.It Fl h Ar host 190Specify the name of an NIS server. 191This option, in conjunction 192with the 193.Fl d 194option, can be used to change an NIS password on a non-local NIS 195server. 196When a domain is specified with the 197.Fl d 198option and 199.Nm 200is unable to determine the name of the NIS master server (possibly because 201the local domainname isn't set), the name of the NIS master is assumed to 202be 203.Dq localhost . 204This can be overridden with the 205.Fl h 206flag. 207The specified hostname need not be the name of an NIS master: the 208name of the NIS master for a given map can be determined by querying any 209NIS server (master or slave) in a domain, so specifying the name of a 210slave server will work equally well. 211.Pp 212.It Fl o 213Do not automatically override the password authentication checks for the 214super-user on the NIS master server; assume 'old' mode instead. 215This 216flag is of limited practical use but is useful for testing. 217.El 218.Sh FILES 219.Bl -tag -width /etc/master.passwd -compact 220.It Pa /etc/master.passwd 221The user database 222.It Pa /etc/passwd 223A Version 7 format password file 224.It Pa /etc/passwd.XXXXXX 225Temporary copy of the password file 226.It Pa /etc/login.conf 227Login class capabilities database 228.It Pa /etc/auth.conf 229configure authentication services 230.El 231.Sh SEE ALSO 232.Xr chpass 1 , 233.Xr kerberos 1 , 234.Xr kinit 1 , 235.Xr login 1 , 236.Xr login.conf 5 , 237.Xr passwd 5 , 238.Xr kpasswdd 8 , 239.Xr pwd_mkdb 8 , 240.Xr vipw 8 241.Rs 242.%A Robert Morris 243.%A Ken Thompson 244.%T "UNIX password security" 245.Re 246.Sh NOTES 247The 248.Xr yppasswd 1 249command is really only a link to 250.Nm . 251.Sh HISTORY 252A 253.Nm 254command appeared in 255.At v6 . 256