1
.\" $OpenBSD: 3.t,v 1.2 1997/01/17 15:54:16 millert Exp $
3
.\" Copyright (c) 1983, 1993
4
.\" The Regents of the University of California. All rights reserved.
6
.\" Redistribution and use in source and binary forms, with or without
7
.\" modification, are permitted provided that the following conditions
9
.\" 1. Redistributions of source code must retain the above copyright
10
.\" notice, this list of conditions and the following disclaimer.
11
.\" 2. Redistributions in binary form must reproduce the above copyright
12
.\" notice, this list of conditions and the following disclaimer in the
13
.\" documentation and/or other materials provided with the distribution.
14
.\" 3. All advertising materials mentioning features or use of this software
15
.\" must display the following acknowledgement:
16
.\" This product includes software developed by the University of
17
.\" California, Berkeley and its contributors.
18
.\" 4. Neither the name of the University nor the names of its contributors
19
.\" may be used to endorse or promote products derived from this software
20
.\" without specific prior written permission.
22
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34
.\" @(#)3.t 8.1 (Berkeley) 6/8/93
39
The printer system maintains protected spooling areas so that
40
users cannot circumvent printer accounting or
41
remove files other than their own.
42
The strategy used to maintain protected
43
spooling areas is as follows:
45
The spooling area is writable only by a \fIdaemon\fP user
46
and \fIdaemon\fP group.
48
The \fIlpr\fP program runs set-user-id to \fIroot\fP and
49
set-group-id to group \fIdaemon\fP. The \fIroot\fP access permits
50
reading any file required. Accessibility is verified
51
with an \fIaccess\fP\|(2) call. The group ID
52
is used in setting up proper ownership of files
53
in the spooling area for \fIlprm\fP.
55
Control files in a spooling area are made with \fIdaemon\fP
56
ownership and group ownership \fIdaemon\fP. Their mode is 0660.
57
This insures control files are not modified by a user
58
and that no user can remove files except through \fIlprm\fP.
60
The spooling programs,
61
\fIlpd\fP, \fIlpq\fP, and \fIlprm\fP run set-user-id to \fIroot\fP
62
and set-group-id to group \fIdaemon\fP to access spool files and printers.
64
The printer server, \fIlpd\fP,
65
uses the same verification procedures as \fIrshd\fP\|(8C)
66
in authenticating remote clients. The host on which a client
67
resides must be present in the file /etc/hosts.equiv or /etc/hosts.lpd and
68
the request message must come from a reserved port number.
70
In practice, none of \fIlpd\fP, \fIlpq\fP, or
71
\fIlprm\fP would have to run as user \fIroot\fP if remote
72
spooling were not supported. In previous incarnations of
73
the printer system \fIlpd\fP ran set-user-id to \fIdaemon\fP,
74
set-group-id to group \fIspooling\fP, and \fIlpq\fP and \fIlprm\fP ran
75
set-group-id to group \fIspooling\fP.
added
removed
SMM.doc/3.t
