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.\" 4. 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.\" $FreeBSD$ 30.\" 31.Dd June 6, 1993 32.Dt PASSWD 1 33.Os 34.Sh NAME 35.Nm passwd , yppasswd 36.Nd modify a user's password 37.Sh SYNOPSIS 38.Nm 39.Op Fl l 40.Op Ar user 41.Nm yppasswd 42.Op Fl l 43.Op Fl y 44.Op Fl d Ar domain 45.Op Fl h Ar host 46.Op Fl o 47.Sh DESCRIPTION 48The 49.Nm 50utility changes the user's local, Kerberos, or NIS password. 51If the user is not the super-user, 52.Nm 53first prompts for the current password and will not continue unless the correct 54password is entered. 55.Pp 56When entering the new password, the characters entered do not echo, in order to 57avoid the password being seen by a passer-by. 58The 59.Nm 60utility prompts for the new password twice in order to detect typing errors. 61.Pp 62The new password should be at least six characters long (which 63may be overridden using the 64.Xr login.conf 5 65.Dq minpasswordlen 66setting for a user's login class) and not purely alphabetic. 67Its total length must be less than 68.Dv _PASSWORD_LEN 69(currently 128 characters). 70.Pp 71The new password should contain a mixture of upper and lower case 72characters (which may be overridden using the 73.Xr login.conf 5 74.Dq mixpasswordcase 75setting for a user's login class). 76Allowing lower case passwords may 77be useful where the password file will be used in situations where only 78lower case passwords are permissible, such as when using Samba to 79authenticate Windows clients. 80In all other situations, numbers, upper 81case letters and meta characters are encouraged. 82.Pp 83Once the password has been verified, 84.Nm 85communicates the new password information to 86the Kerberos authenticating host. 87.Pp 88The following option is available: 89.Bl -tag -width indent 90.It Fl l 91Cause the password to be updated only in the local 92password file, and not with the Kerberos database. 93When changing only the local password, 94.Xr pwd_mkdb 8 95is used to update the password databases. 96.El 97.Pp 98When changing local or NIS password, the next password change date 99is set according to 100.Dq passwordtime 101capability in the user's login class. 102.Pp 103To change another user's Kerberos password, one must first 104run 105.Xr kinit 1 106followed by 107.Nm . 108The super-user is not required to provide a user's current password 109if only the local password is modified. 110.Sh NIS INTERACTION 111The 112.Nm 113utility has built-in support for NIS. 114If a user exists in the NIS password 115database but does not exist locally, 116.Nm 117automatically switches into 118.Nm yppasswd 119mode. 120If the specified 121user does not exist in either the local password database or the 122NIS password maps, 123.Nm 124returns an error. 125.Pp 126When changing an NIS password, unprivileged users are required to provide 127their old password for authentication (the 128.Xr rpc.yppasswdd 8 129daemon requires the original password before 130it will allow any changes to the NIS password maps). 131This restriction applies even to the 132super-user, with one important exception: the password authentication is 133bypassed for the super-user on the NIS master server. 134This means that 135the super-user on the NIS master server can make unrestricted changes to 136anyone's NIS password. 137The super-user on NIS client systems and NIS slave 138servers still needs to provide a password before the update will be processed. 139.Pp 140The following additional options are supported for use with NIS: 141.Bl -tag -width indent 142.It Fl y 143Override 144.Nm Ns 's 145checking heuristics and forces 146it into NIS mode. 147.It Fl l 148When NIS is enabled, the 149.Fl l 150flag can be used to force 151.Nm 152into 153.Dq local only 154mode. 155This flag can be used to change the entry 156for a local user when an NIS user exists with the same login name. 157For example, you will sometimes find entries for system 158.Dq placeholder 159users such as 160.Pa bin 161or 162.Pa daemon 163in both the NIS password maps and the local user database. 164By 165default, 166.Nm 167will try to change the NIS password. 168The 169.Fl l 170flag can be used to change the local password instead. 171.It Fl d Ar domain 172Specify what domain to use when changing an NIS password. 173By default, 174.Nm 175assumes that the system default domain should be used. 176This flag is 177primarily for use by the superuser on the NIS master server: a single 178NIS server can support multiple domains. 179It is also possible that the 180domainname on the NIS master may not be set (it is not necessary for 181an NIS server to also be a client) in which case the 182.Nm 183command needs to be told what domain to operate on. 184.It Fl h Ar host 185Specify the name of an NIS server. 186This option, in conjunction 187with the 188.Fl d 189option, can be used to change an NIS password on a non-local NIS 190server. 191When a domain is specified with the 192.Fl d 193option and 194.Nm 195is unable to determine the name of the NIS master server (possibly because 196the local domainname is not set), the name of the NIS master is assumed to 197be 198.Dq localhost . 199This can be overridden with the 200.Fl h 201flag. 202The specified hostname need not be the name of an NIS master: the 203name of the NIS master for a given map can be determined by querying any 204NIS server (master or slave) in a domain, so specifying the name of a 205slave server will work equally well. 206.It Fl o 207Do not automatically override the password authentication checks for the 208super-user on the NIS master server; assume 209.Dq old 210mode instead. 211This 212flag is of limited practical use but is useful for testing. 213.El 214.Sh FILES 215.Bl -tag -width /etc/master.passwd -compact 216.It Pa /etc/master.passwd 217the user database 218.It Pa /etc/passwd 219a Version 7 format password file 220.It Pa /etc/passwd.XXXXXX 221temporary copy of the password file 222.It Pa /etc/login.conf 223login class capabilities database 224.It Pa /etc/auth.conf 225configure authentication services 226.El 227.Sh SEE ALSO 228.Xr chpass 1 , 229.Xr kinit 1 , 230.Xr login 1 , 231.Xr login.conf 5 , 232.Xr passwd 5 , 233.Xr kerberos 8 , 234.Xr kpasswdd 8 , 235.Xr pw 8 , 236.Xr pwd_mkdb 8 , 237.Xr vipw 8 238.Rs 239.%A Robert Morris 240.%A Ken Thompson 241.%T "UNIX password security" 242.Re 243.Sh NOTES 244The 245.Nm yppasswd 246command is really only a link to 247.Nm . 248.Sh HISTORY 249A 250.Nm 251command appeared in 252.At v6 . 253