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 1.2 2003/06/17 04:29:30 dillon 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). Allowing lower case passwords may 81be useful where the password file will be used in situations where only 82lower case passwords are permissible, such as when using Samba to 83authenticate Windows clients. In all other situations, numbers, upper 84case letters and meta characters are encouraged. 85.Pp 86Once the password has been verified, 87.Nm 88communicates the new password information to 89the Kerberos authenticating host. 90.Bl -tag -width flag 91.It Fl l 92This option causes the password to be updated only in the local 93password file, and not with the Kerberos database. 94When changing only the local password, 95.Xr pwd_mkdb 8 96is used to update the password databases. 97.Pp 98.El 99When changing local or NIS password, the next password change date 100is set according to 101.Dq passwordtime 102capability in the user's login class. 103.Pp 104To change another user's Kerberos password, one must first 105run 106.Xr kinit 1 107followed by 108.Xr passwd 1 . 109The super-user is not required to provide a user's current password 110if only the local password is modified. 111.Sh NIS INTERACTION 112The 113.Nm 114utility has built-in support for NIS. 115If a user exists in the NIS password 116database but does not exist locally, 117.Nm 118automatically switches into 119.Dq yppasswd 120mode. 121If the specified 122user does not exist in either the local password database of the 123NIS password maps, 124.Nm 125returns an error. 126.Pp 127When changing an NIS password, unprivileged users are required to provide 128their old password for authentication (the 129.Xr rpc.yppasswdd 8 130daemon requires the original password before 131it will allow any changes to the NIS password maps). 132This restriction applies even to the 133super-user, with one important exception: the password authentication is 134bypassed for the super-user on the NIS master server. 135This means that 136the super-user on the NIS master server can make unrestricted changes to 137anyone's NIS password. 138The super-user on NIS client systems and NIS slave 139servers still needs to provide a password before the update will be processed. 140.Pp 141The following additional options are supported for use with NIS: 142.Bl -tag -width flag 143.It Fl y 144The 145.Fl y 146flag overrides 147.Nm Ns 's 148checking heuristics and forces 149it into NIS mode. 150.It Fl l 151When NIS is enabled, the 152.Fl l 153flag can be used to force 154.Nm 155into 156.Dq local only 157mode. 158This flag can be used to change the entry 159for a local user when an NIS user exists with the same login name. 160For example, you will sometimes find entries for system 161.Dq placeholder 162users such as 163.Pa bin 164or 165.Pa daemon 166in both the NIS password maps and the local user database. 167By 168default, 169.Nm 170will try to change the NIS password. 171The 172.Fl l 173flag can be used to change the local password instead. 174.It Fl d Ar domain 175Specify what domain to use when changing an NIS password. 176By default, 177.Nm 178assumes that the system default domain should be used. 179This flag is 180primarily for use by the superuser on the NIS master server: a single 181NIS server can support multiple domains. 182It is also possible that the 183domainname on the NIS master may not be set (it is not necessary for 184an NIS server to also be a client) in which case the 185.Nm 186command needs to be told what domain to operate on. 187.It Fl h Ar host 188Specify the name of an NIS server. 189This option, in conjunction 190with the 191.Fl d 192option, can be used to change an NIS password on a non-local NIS 193server. 194When a domain is specified with the 195.Fl d 196option and 197.Nm 198is unable to determine the name of the NIS master server (possibly because 199the local domainname isn't set), the name of the NIS master is assumed to 200be 201.Dq localhost . 202This can be overridden with the 203.Fl h 204flag. 205The specified hostname need not be the name of an NIS master: the 206name of the NIS master for a given map can be determined by querying any 207NIS server (master or slave) in a domain, so specifying the name of a 208slave server will work equally well. 209.Pp 210.It Fl o 211Do not automatically override the password authentication checks for the 212super-user on the NIS master server; assume 'old' mode 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 kerberos 1 , 232.Xr kinit 1 , 233.Xr login 1 , 234.Xr login.conf 5 , 235.Xr passwd 5 , 236.Xr kpasswdd 8 , 237.Xr pwd_mkdb 8 , 238.Xr vipw 8 239.Rs 240.%A Robert Morris 241.%A Ken Thompson 242.%T "UNIX password security" 243.Re 244.Sh NOTES 245The 246.Xr yppasswd 1 247command is really only a link to 248.Nm . 249.Sh HISTORY 250A 251.Nm 252command appeared in 253.At v6 . 254