357 lines
11 KiB
Groff
357 lines
11 KiB
Groff
.\" Copyright (c) 1995, 1996
|
|
.\" Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by Bill Paul.
|
|
.\" 4. Neither the name of the author nor the names of contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd February 8, 1996
|
|
.Dt RPC.YPPASSWDD 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm rpc.yppasswdd
|
|
.Nd "server for updating NIS passwords"
|
|
.Sh SYNOPSIS
|
|
.Nm rpc.yppasswdd
|
|
.Op Fl t Ar master.passwd template file
|
|
.Op Fl d Ar default domain
|
|
.Op Fl p Ar path
|
|
.Op Fl s
|
|
.Op Fl f
|
|
.Op Fl a
|
|
.Op Fl m
|
|
.Op Fl i
|
|
.Op Fl v
|
|
.Op Fl u
|
|
.Op Fl h
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
daemon allows users to change their NIS passwords and certain
|
|
other information using the
|
|
.Xr yppasswd 1
|
|
and
|
|
.Xr ypchpass 1
|
|
commands.
|
|
.Nm Rpc.yppasswdd
|
|
is an RPC-based server that accepts incoming password change requests,
|
|
authenticates them, places the updated information in the
|
|
.Pa /var/yp/master.passwd
|
|
template file and then updates the NIS
|
|
.Pa master.passwd
|
|
and
|
|
.Pa passwd
|
|
maps.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
server allows a normal NIS user to change
|
|
his or her NIS password, full name (also
|
|
known as 'GECOS' field) or shell.
|
|
These updates are typically done using
|
|
the
|
|
.Xr yppasswd 1 ,
|
|
.Xr ypchfn 1 ,
|
|
.Xr ypchsh 1 ,
|
|
or
|
|
.Xr ypchpass 1
|
|
commands.
|
|
(Some administrators don't want users to be able to change their
|
|
full name information or shells; the server can be invoked with option flags
|
|
that disallow such changes.)
|
|
When the server receives an update request,
|
|
it compares the address of the client making the request against the
|
|
.Pa securenets
|
|
rules outlined in
|
|
.Pa /var/yp/securenets .
|
|
(See the
|
|
.Xr ypserv 8
|
|
manual page for more information on securenets; the
|
|
.Nm
|
|
server uses the same access control mechanism as
|
|
.Xr ypserv 8 .)
|
|
.Pp
|
|
The server then
|
|
checks the 'old' password supplied by the user to make sure it's
|
|
valid, then performs some sanity checks on the updated information (these
|
|
include checking for embedded control characters, colons or invalid shells).
|
|
Once it is satisfied that the update request is valid, the server modifies
|
|
the template password file (the default is
|
|
.Pa /var/yp/master.passwd )
|
|
and then runs the
|
|
.Pa /usr/libexec/yppwupdate
|
|
script to rebuild the NIS maps.
|
|
(This script has two arguments passed
|
|
to it: the absolute pathname of the password template that was modified
|
|
and the name of the domain that is to be updated.
|
|
These in turn are
|
|
passed to
|
|
.Pa /var/yp/Makefile ) .
|
|
.Pp
|
|
The
|
|
.Bx Free
|
|
version of
|
|
.Nm
|
|
also allows the super-user on the NIS master server to perform more
|
|
sophisticated updates on the NIS passwd maps.
|
|
The super-user can modify
|
|
any field in any user's master.passwd entry in any domain, and can
|
|
do so without knowing the user's existing NIS password (when the server
|
|
receives a request from the super-user, the password authentication
|
|
check is bypassed). Furthermore, if the server is invoked with the
|
|
.Fl a
|
|
flag, the super-user can even add new entries to the maps using
|
|
.Xr ypchpass 1 .
|
|
Again, this only applies to the super-user on the NIS
|
|
master server: none of these special functions can be peformed over
|
|
the network.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
daemon can only be run on a machine that is an NIS master server.
|
|
.Sh OPTIONS
|
|
The following options are available:
|
|
.Bl -tag -width indent
|
|
.It Fl t Ar master.passwd template file
|
|
By default,
|
|
.Nm
|
|
assumes that the template file used to generates the
|
|
.Pa master.passwd
|
|
and
|
|
.Pa passwd
|
|
maps for the default domain is called
|
|
.Pa /var/yp/master.passwd .
|
|
This default can be overridden by specifying an alternate file name
|
|
with the
|
|
.Fl t
|
|
flag.
|
|
.Pp
|
|
Note: if the template file specified with this flag is
|
|
.Pa /etc/master.passwd ,
|
|
.Nm
|
|
will also automatically invoke
|
|
.Xr pwd_mkdb 8
|
|
to rebuild the local password databases in addition to the NIS
|
|
maps.
|
|
.It Fl d Ar domain
|
|
The
|
|
.Nm
|
|
server can support multiple domains, however it must
|
|
choose one domain as a default.
|
|
It will try to use the system default domain name as set by the
|
|
.Xr domainname 1
|
|
command for this default.
|
|
However,
|
|
if the system domain name is not
|
|
set, a default domain must be specified on
|
|
the command line.
|
|
If the system default domain is set,
|
|
then this option can be used to override it.
|
|
.It Fl p Ar path
|
|
This option can be used to override the default path to
|
|
the location of the NIS
|
|
map databases.
|
|
The compiled-in default path is
|
|
.Pa /var/yp .
|
|
.It Fl s
|
|
Disallow changing of shell information.
|
|
.It Fl f
|
|
Disallow changing of full name ('GECOS') information.
|
|
.It Fl a
|
|
Allow additions to be made to the NIS passwd databases.
|
|
The super-user on the
|
|
NIS master server is permitted to use the
|
|
.Xr ypchpass 1
|
|
command to perform unrestricted modifications to any field in a user's
|
|
.Pa master.passwd
|
|
map entry.
|
|
When
|
|
.Nm
|
|
is started with this flag, it will also allow the super-user to add new
|
|
records to the NIS passwd maps, just as is possible when using
|
|
.Xr chpass 1
|
|
to modify the local password database.
|
|
.It Fl m
|
|
Turn on multi-domain mode.
|
|
Even though
|
|
.Xr ypserv 8
|
|
can handle several simultaneous domains, most implementations of
|
|
.Nm
|
|
can only operate on a single NIS domain, which is generally the same as
|
|
the system default domain of the NIS master server.
|
|
The
|
|
.Bx Free
|
|
.Nm
|
|
attempts to overcome this problem in spite of the inherent limitations
|
|
of the
|
|
.Pa yppasswd
|
|
protocol, which does not allow for a
|
|
.Pa domain
|
|
argument in client requests.
|
|
In multi-domain mode,
|
|
.Nm
|
|
will search through all the passwd maps of all the domains it
|
|
can find under
|
|
.Pa /var/yp
|
|
until it finds an entry that matches the user information specified in
|
|
a given update request.
|
|
(Matches are determined by checking the username,
|
|
UID and GID fields.)
|
|
The matched entry and corresponding domain are then
|
|
used for the update.
|
|
.Pp
|
|
Note that in order for multi-domain mode to work, there have to be
|
|
seperate template files for each domain.
|
|
For example, if a server
|
|
supports three domains,
|
|
.Pa foo ,
|
|
.Pa bar ,
|
|
and
|
|
.Pa baz ,
|
|
there should be three seperate master.passwd template files called
|
|
.Pa /var/yp/foo/master.passwd ,
|
|
.Pa /var/yp/bar/master.passwd ,
|
|
and
|
|
.Pa /var/yp/baz/master.passwd .
|
|
If
|
|
.Pa foo
|
|
happens to be the system default domain, then its template file can
|
|
be either
|
|
.Pa /var/yp/foo/master.passwd
|
|
or
|
|
.Pa /var/yp/master.passwd .
|
|
The server will check for the latter file first and then use the former
|
|
if it can't find it.
|
|
.Pp
|
|
Multi-domain mode is off by default since it can fail if there are
|
|
duplicate or near-duplicate user entries in different domains.
|
|
The server
|
|
will abort an update request if it finds more than one user entry that
|
|
matches its search criteria.
|
|
Even so, paranoid administrators
|
|
may wish to leave multi-domain mode disabled.
|
|
.It Fl i
|
|
If
|
|
.Nm
|
|
is invoked with this flag, it will perform map updates in place.
|
|
This
|
|
means that instead of just modifying the password template file and
|
|
starting a map update, the server will modify the map databases
|
|
directly.
|
|
This is useful when the password maps are large: if, for
|
|
example, the password database has tens of thousands of entries, it
|
|
can take several minutes for a map update to complete.
|
|
Updating the
|
|
maps in place reduces this time to a few seconds.
|
|
.It Fl v
|
|
Turn on verbose logging mode.
|
|
The server normally only logs messages
|
|
using the
|
|
.Xr syslog 3
|
|
facility when it encounters an error condition, or when processing
|
|
updates for the super-user on the NIS master server.
|
|
Running the server
|
|
with the
|
|
.Fl v
|
|
flag will cause it to log informational messages for all updates.
|
|
.It Fl u
|
|
Many commercial
|
|
.Xr yppasswd 1
|
|
clients do not use a reserved port when sending requests to
|
|
.Nm rpc.yppasswdd .
|
|
This is either because the
|
|
.Xr yppasswd 1
|
|
program is not installed set-uid root, or because the RPC
|
|
implementation does not place any emphasis on binding to reserved
|
|
ports when establishing client connections for the super-user.
|
|
By default,
|
|
.Nm
|
|
expects to receive requests from clients using reserved ports; requests
|
|
received from non-privileged ports are rejected.
|
|
Unfortunately, this
|
|
behavior prevents any client systems that to not use privileged
|
|
ports from sucessfully submitting password updates.
|
|
Specifying
|
|
the
|
|
.Fl u
|
|
flag to
|
|
.Nm
|
|
disables the privileged port check so that it will work with
|
|
.Xr yppasswd 1
|
|
clients that don't use privileged ports.
|
|
This reduces security to
|
|
a certain small degree, but it might be necessary in cases where it
|
|
is not possible to change the client behavior.
|
|
.It Fl h
|
|
Display the list of flags and options understood by
|
|
.Nm rpc.yppasswdd .
|
|
.El
|
|
.Sh FILES
|
|
.Bl -tag -width Pa -compact
|
|
.It Pa /usr/libexec/yppwupdate
|
|
The script invoked by
|
|
.Nm
|
|
to update and push the NIS maps after
|
|
an update.
|
|
.It Pa /var/yp/master.passwd
|
|
The template password file for the default domain.
|
|
.It Pa /var/yp/[domainname]/[maps]
|
|
The NIS maps for a particular NIS domain.
|
|
.It Pa /var/yp/[domainname]/master.passwd
|
|
The template password file(s) for non-default domains
|
|
(used only in multi-domain mode).
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr yp 4 ,
|
|
.Xr yppush 8 ,
|
|
.Xr ypserv 8 ,
|
|
.Xr ypxfr 8
|
|
.Sh BUGS
|
|
As listed in the yppasswd.x protocol definition, the YPPASSWDPROC_UPDATE
|
|
procedure takes two arguments: a V7-style passwd structure containing
|
|
updated user information and the user's existing unencrypted (cleartext)
|
|
password.
|
|
Since
|
|
.Nm
|
|
is supposed to handle update requests from remote NIS client machines,
|
|
this means that
|
|
.Xr yppasswd 1
|
|
and similar client programs will in fact be transmitting users' cleartext
|
|
passwords over the network.
|
|
.Pp
|
|
This is not a problem for password updates since the plaintext password
|
|
sent with the update will no longer be valid once the new encrypted password
|
|
is put into place, but if the user is only updating his or her 'GECOS'
|
|
information or shell, then the cleartext password sent with the update
|
|
will still be valid once the update is completed.
|
|
If the network is
|
|
insecure, this cleartext password could be intercepted and used to
|
|
gain unauthorized access to the user's account.
|
|
.Sh AUTHORS
|
|
.An Bill Paul Aq wpaul@ctr.columbia.edu
|