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 1.4 2005/08/05 22:35:11 swildner Exp $ 35.\" 36.Dd June 6, 1993 37.Dt PASSWD 1 38.Os 39.Sh NAME 40.Nm passwd , 41.Nm yppasswd 42.Nd modify a user's password 43.Sh SYNOPSIS 44.Nm 45.Op Fl l 46.Op Ar user 47.Nm yppasswd 48.Op Fl l 49.Op Fl y 50.Op Fl d Ar domain 51.Op Fl h Ar host 52.Op Fl o 53.Sh DESCRIPTION 54The 55.Nm 56utility changes the user's local, Kerberos, or NIS password. 57If the user is not the super-user, 58.Nm 59first prompts for the current password and will not continue unless the correct 60password is entered. 61.Pp 62When entering the new password, the characters entered do not echo, in order to 63avoid the password being seen by a passer-by. 64The 65.Nm 66utility prompts for the new password twice in order to detect typing errors. 67.Pp 68The new password should be at least six characters long (which 69may be overridden using the 70.Xr login.conf 5 71.Dq minpasswordlen 72setting for a user's login class) and not purely alphabetic. 73Its total length must be less than 74.Dv _PASSWORD_LEN 75(currently 128 characters). 76.Pp 77The new password should contain a mixture of upper and lower case 78characters (which may be overridden using the 79.Xr login.conf 5 80.Dq mixpasswordcase 81setting for a user's login class). 82Allowing lower case passwords may 83be useful where the password file will be used in situations where only 84lower case passwords are permissible, such as when using Samba to 85authenticate Windows clients. 86In all other situations, numbers, upper 87case letters and meta characters are encouraged. 88.Pp 89Once the password has been verified, 90.Nm 91communicates the new password information to 92the Kerberos authenticating host. 93.Bl -tag -width flag 94.It Fl l 95This option causes the password to be updated only in the local 96password file, and not with the Kerberos database. 97When changing only the local password, 98.Xr pwd_mkdb 8 99is used to update the password databases. 100.Pp 101.El 102When changing local or NIS password, the next password change date 103is set according to 104.Dq passwordtime 105capability in the user's login class. 106.Pp 107To change another user's Kerberos password, one must first 108run 109.Xr kinit 1 110followed by 111.Xr passwd 1 . 112The super-user is not required to provide a user's current password 113if only the local password is modified. 114.Sh NIS INTERACTION 115The 116.Nm 117utility has built-in support for NIS. 118If a user exists in the NIS password 119database but does not exist locally, 120.Nm 121automatically switches into 122.Dq yppasswd 123mode. 124If the specified 125user does not exist in either the local password database of the 126NIS password maps, 127.Nm 128returns an error. 129.Pp 130When changing an NIS password, unprivileged users are required to provide 131their old password for authentication (the 132.Xr rpc.yppasswdd 8 133daemon requires the original password before 134it will allow any changes to the NIS password maps). 135This restriction applies even to the 136super-user, with one important exception: the password authentication is 137bypassed for the super-user on the NIS master server. 138This means that 139the super-user on the NIS master server can make unrestricted changes to 140anyone's NIS password. 141The super-user on NIS client systems and NIS slave 142servers still needs to provide a password before the update will be processed. 143.Pp 144The following additional options are supported for use with NIS: 145.Bl -tag -width flag 146.It Fl y 147The 148.Fl y 149flag overrides 150.Nm Ns 's 151checking heuristics and forces 152it into NIS mode. 153.It Fl l 154When NIS is enabled, the 155.Fl l 156flag can be used to force 157.Nm 158into 159.Dq local only 160mode. 161This flag can be used to change the entry 162for a local user when an NIS user exists with the same login name. 163For example, you will sometimes find entries for system 164.Dq placeholder 165users such as 166.Pa bin 167or 168.Pa daemon 169in both the NIS password maps and the local user database. 170By 171default, 172.Nm 173will try to change the NIS password. 174The 175.Fl l 176flag can be used to change the local password instead. 177.It Fl d Ar domain 178Specify what domain to use when changing an NIS password. 179By default, 180.Nm 181assumes that the system default domain should be used. 182This flag is 183primarily for use by the superuser on the NIS master server: a single 184NIS server can support multiple domains. 185It is also possible that the 186domainname on the NIS master may not be set (it is not necessary for 187an NIS server to also be a client) in which case the 188.Nm 189command needs to be told what domain to operate on. 190.It Fl h Ar host 191Specify the name of an NIS server. 192This option, in conjunction 193with the 194.Fl d 195option, can be used to change an NIS password on a non-local NIS 196server. 197When a domain is specified with the 198.Fl d 199option and 200.Nm 201is unable to determine the name of the NIS master server (possibly because 202the local domainname isn't set), the name of the NIS master is assumed to 203be 204.Dq localhost . 205This can be overridden with the 206.Fl h 207flag. 208The specified hostname need not be the name of an NIS master: the 209name of the NIS master for a given map can be determined by querying any 210NIS server (master or slave) in a domain, so specifying the name of a 211slave server will work equally well. 212.Pp 213.It Fl o 214Do not automatically override the password authentication checks for the 215super-user on the NIS master server; assume 'old' mode instead. 216This 217flag is of limited practical use but is useful for testing. 218.El 219.Sh FILES 220.Bl -tag -width /etc/master.passwd -compact 221.It Pa /etc/master.passwd 222The user database 223.It Pa /etc/passwd 224A Version 7 format password file 225.It Pa /etc/passwd.XXXXXX 226Temporary copy of the password file 227.It Pa /etc/login.conf 228Login class capabilities database 229.It Pa /etc/auth.conf 230configure authentication services 231.El 232.Sh SEE ALSO 233.Xr chpass 1 , 234.Xr kerberos 1 , 235.Xr kinit 1 , 236.Xr login 1 , 237.Xr login.conf 5 , 238.Xr passwd 5 , 239.Xr kpasswdd 8 , 240.Xr pwd_mkdb 8 , 241.Xr vipw 8 242.Rs 243.%A Robert Morris 244.%A Ken Thompson 245.%T "UNIX password security" 246.Re 247.Sh NOTES 248The 249.Xr yppasswd 1 250command is really only a link to 251.Nm . 252.Sh HISTORY 253A 254.Nm 255command appeared in 256.At v6 . 257