summaryrefslogtreecommitdiff
path: root/doc/saned.man
blob: d019901119413e2189dd0820e64a0c7c713655f0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
.TH saned 8 "29 Sep 2017" "@PACKAGEVERSION@" "SANE Scanner Access Now Easy"
.IX saned
.SH NAME
saned \- SANE network daemon
.SH SYNOPSIS
.B saned
.B [ \-a
.I [ username ]
.B ]
.B [ \-u
.I username
.B ]
.B [ \-b
.I address
.B ]
.B [ \-l ]
.B [ \-D ]
.B [ \-o ]
.B [ \-d
.I n
.B ]
.B [ \-e ]
.B [ \-h ]
.SH DESCRIPTION
.B saned
is the SANE (Scanner Access Now Easy) daemon that allows remote clients
to access image acquisition devices available on the local host.
.SH OPTIONS
.PP
The
.B \-l
flag requests that
.B saned
run in standalone daemon mode.  In this mode,
.B saned
will listen for incoming client connections;
.B inetd
is not required for
.B saned
operations in this mode. The
.B \-b
flag tells
.B saned
to bind to the
.I address
given.  The
.B \-u
flag requests that
.B saned
drop root privileges and run as the user (and group) associated with
.I username
after binding.
The
.B \-D
flag will request
.B saned
to detach from the console and run in the background.
The flag
.B \-a
is equivalent to the combination of
.B \-l \-B \-u
.I username
options.
.PP
The
.B \-d
flag sets the level of
.B saned
debug output.  When compiled with debugging enabled, this flag may be
followed by a number to request more or less debug info.  The larger
the number, the more verbose the debug output.  E.g.,
.B \-d128
will request output of all debug info.  A level of 0 produces no
output at all.  The default value is 2.
.PP
The
.B \-e
flag will divert
.B saned
debug output to stderr instead of the syslog default.
.PP
The
.B \-o
flag requests that
.B saned
exits after the first client disconnects.  This is useful for debugging.
.PP
The
.B \-h
flag displays a short help message.
.PP
If
.B saned
is run from other programs such as inetd, xinetd and systemd, check that
program's documentation on how to pass command-line options.
.SH CONFIGURATION
First and foremost:
.B saned
is not intended to be exposed to the internet or other non-trusted
networks. Make sure that access is limited by tcpwrappers and/or a firewall
setup. Don't depend only on
.BR saned 's
own authentication. Don't run
.B saned
as root if it's not necessary. And do
.B not
install
.B saned
as setuid root.
.PP
The
.I saned.conf
configuration file contains both options for the daemon and the access
list.
.TP
\fBdata_portrange\fP = \fImin_port\fP - \fImax_port\fP
Specify the port range to use for the data connection. Pick a port
range between 1024 and 65535; don't pick a too large port range, as it
may have performance issues. Use this option if your \fBsaned\fP
server is sitting behind a firewall. If that firewall is a Linux
machine, we strongly recommend using the Netfilter
\fInf_conntrack_sane\fP module instead.
.TP
\fBdata_connect_timeout\fP = \fItimeout\fP
Specify the time in milliseconds that saned will wait for a data
connection. Without this option, if the data connection is not done
before the scanner reaches the end of scan, the scanner will continue
to scan past the end and may damage it depending on the
backend. Specify zero to have the old behavior. The default is 4000ms.
.PP
The access list is a list of host names, IP addresses or IP subnets
(CIDR notation) that are permitted to use local SANE devices. IPv6
addresses must be enclosed in brackets, and should always be specified
in their compressed form. Connections from localhost are always
permitted. Empty lines and lines starting with a hash mark (#) are
ignored. A line containing the single character ``+'' is interpreted
to match any hostname. This allows any remote machine to use your
scanner and may present a security risk, so this shouldn't be used
unless you know what you're doing.
.PP
A sample configuration file is shown below:
.PP
.RS
# Daemon options
.br
data_portrange = 10000 - 10100
.br
# Access list
.br
scan\-client.somedomain.firm
.br
# this is a comment
.br
192.168.0.1
.br
192.168.2.12/29
.br
[::1]
.br
[2001:db8:185e::42:12]/64
.RE
.PP
The case of the host names does not matter, so AHost.COM is considered
identical to ahost.com.
.SH SERVER DAEMON CONFIGURATION
For
.B saned
to work properly in its default mode of operation, it is also necessary to
add the appropriate configuration for
.I (x)inetd or systemd.
(see below).
Note that your inetd must support IPv6 if you
want to connect to saned over IPv6 ; xinetd, openbsd-inetd and systemd
are known to support IPv6, check the documentation for your inetd daemon.
.PP
In the sections below the configuration for
.I inetd, xinetd
and
.I systemd
are described in more detail.
.PP
For the configurations below it is necessary to add a line of the following
form to
.IR /etc/services :
.PP
.RS
sane\-port 6566/tcp # SANE network scanner daemon
.RE
.PP
The official IANA short name for port 6566 is "sane\-port". The older name
"sane" is now deprecated.
.SH INETD CONFIGURATION
It is required to add a single line to the inetd configuration file
.IR (/etc/inetd.conf)
.
.PP
The configuration line normally looks like this:
.PP
.RS
sane\-port stream tcp nowait saned.saned @SBINDIR@/saned saned
.RE
.PP
However, if your system uses
.BR tcpd (8)
for additional security screening, you may want to disable saned
access control by putting ``+'' in
.IR saned.conf
and use a line of the following form in
.IR /etc/inetd.conf
instead:
.PP
.RS
sane\-port stream tcp nowait saned.saned /usr/sbin/tcpd @SBINDIR@/saned
.RE
.PP
Note that both examples assume that there is a
.B saned
group and a
.B saned
user.  If you follow this example, please make sure that the
access permissions on the special device are set such that
.B saned
can access the scanner (the program generally needs read and
write access to scanner devices).
.SH XINETD CONFIGURATION
If xinetd is installed on your system instead of inetd the following example
for
.I /etc/xinetd.conf
may be helpful:
.PP
.RS
.ft CR
.nf
# default: off
# description: The sane server accepts requests
# for network access to a local scanner via the
# network.
service sane\-port
{
   port        = 6566
   socket_type = stream
   wait        = no
   user        = saned
   group       = saned
   server      = @SBINDIR@/saned
}
.fi
.ft R
.RE
.SH SYSTEMD CONFIGURATION
Saned can be compiled with explicit systemd support. This
will allow logging debugging information to be forwarded
to the systemd journal. The systemd support
requires compilation with the systemd-devel package
installed on the system. this is the preferred option.

Saned can be used wih systemd without the systemd integration
compiled in, but then logging of debug information is not supported.

The systemd configuration is different for the 2 options, so
both are described below.
.SH Systemd configuration for saned with systemd support compiled in
for the systemd configuration we need to add 2 configuration files in
.I /etc/systemd/system.
.PP
The first file we need to add here is called
.I saned.socket.
It shall have
the following contents:
.PP
.RS
.ft CR
.nf
[Unit]
Description=saned incoming socket

[Socket]
ListenStream=6566
Accept=yes
MaxConnections=1

[Install]
WantedBy=sockets.target
.fi
.ft R
.RE
.PP
The second file to be added is
.I saned@.service
with the following contents:
.PP
.RS
.ft CR
.nf
[Unit]
Description=Scanner Service
Requires=saned.socket

[Service]
ExecStart=/usr/sbin/saned
User=saned
Group=saned
StandardInput=null
StandardOutput=syslog
StandardError=syslog
Environment=SANE_CONFIG_DIR=@CONFIGDIR@
# If you need to debug your configuration uncomment the next line and
# change it as appropriate to set the desired debug options
# Environment=SANE_DEBUG_DLL=255 SANE_DEBUG_BJNP=5

[Install]
Also=saned.socket
.fi
.ft R
.RE
.PP
You need to set an environment variable for
.B SANE_CONFIG_DIR
pointing to the directory where saned can find its configuration files.
you will have to remove the # on the last line and set the variables
for the desired debugging information if required.  Multiple variables
can be set by separating the assignments by spaces as shown in the
example above.
.PP
Unlike
.I (x)inetd
, systemd allows debugging output from backends set using
.B SANE_DEBUG_XXX
to be captured. See the man-page for your backend to see what options
are  supported.
With the service unit as described above, the debugging output is
forwarded to the system log.

.SH Systemd configuration when saned is compiled without systemd support
This configuration will also work when Saned is compiled WITH systemd integration
support, but it does not allow debugging information to be logged.
.PP
for systemd configuration for saned, we need to add 2 configuration files in
.I /etc/systemd/system.
.PP
The first file we need to add here is called
.I saned.socket.
It is identical to the version for systemd with the support compiled in.
It shall have the following contents:
.PP
.RS
.ft CR
.nf
[Unit]
Description=saned incoming socket

[Socket]
ListenStream=6566
Accept=yes
MaxConnections=1

[Install]
WantedBy=sockets.target
.fi
.ft R
.RE
.PP
The second file to be added is
.I saned@.service
This one differes from the sersion with systemd integration compiled in:
.PP
.RS
.ft CR
.nf
[Unit]
Description=Scanner Service
Requires=saned.socket

[Service]
ExecStart=/usr/sbin/saned
User=saned
Group=saned
StandardInput=socket

Environment=SANE_CONFIG_DIR=/etc/sane.d

[Install]
Also=saned.socket
.fi
.ft R
.RE
.PP

.SH FILES
.TP
.I /etc/hosts.equiv
The hosts listed in this file are permitted to access all local SANE
devices.  Caveat: this file imposes serious security risks and its use
is not recommended.
.TP
.I @CONFIGDIR@/saned.conf
Contains a list of hosts permitted to access local SANE devices (see
also description of
.B SANE_CONFIG_DIR
below).
.TP
.I @CONFIGDIR@/saned.users
If this file contains lines of the form

user:password:backend

access to the listed backends is restricted. A backend may be listed multiple
times for different user/password combinations. The server uses MD5 hashing
if supported by the client.
.SH ENVIRONMENT
.TP
.B SANE_CONFIG_DIR
This environment variable specifies the list of directories that may
contain the configuration file.  Under UNIX, the directories are
separated by a colon (`:'), under OS/2, they are separated by a
semi-colon (`;').  If this variable is not set, the configuration file
is searched in two default directories: first, the current working
directory (".") and then in @CONFIGDIR@.  If the value of the
environment variable ends with the directory separator character, then
the default directories are searched after the explicitly specified
directories.  For example, setting
.B SANE_CONFIG_DIR
to "/tmp/config:" would result in directories "tmp/config", ".", and
"@CONFIGDIR@" being searched (in this order).

.SH "SEE ALSO"
.BR sane (7),
.BR scanimage (1),
.BR xscanimage (1),
.BR xcam (1),
.BR sane\-dll (5),
.BR sane\-net (5),
.BR sane\-"backendname" (5)
.br
.I http://www.penguin-breeder.org/?page=sane\-net
.SH AUTHOR
David Mosberger