saned - SANE network daemon
saned [-d|-s [n]]
saned is the SANE (Scanner Access Now Easy) daemon that allows remote
clients to access image acquisition devices available on the local
host.
The -d and -s flags request that saned run in debug mode (as opposed to
inetd(8) mode). In this mode, saned explicitly waits for a connection
request. When compiled with debugging enabled, these flags may be followed
by a number to request debug info. The larger the number, the
more verbose the debug output. E.g., -d128 will request printing of
all debug info. Debug level 0 means no debug output at all. The default
value is 2. If flag -d is used, the debug messages will be printed to
stderr while -s requests using syslog.
First and foremost: please do not install saned as setuid root without
due consideration. Especially when using dynamic linking, there is a
potential for introducing security holes when running this program as
root.
The contents of the saned.conf file is a list of host names or IP
addresses that are permitted to use local SANE devices. 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. A sample configuration
file is shown below:
scan-client.somedomain.firm
# this is a comment
192.168.0.1
The case of the host names does not matter, so AHost.COM is considered
identical to ahost.com.
For saned to work properly, it is also necessary to add a configuration
line to /etc/inetd.conf. The configuration line normally looks like
this:
sane stream tcp nowait saned.saned /usr/sbin/saned saned
However, if your system uses tcpd(8) for additional security screening,
you may want to disable saned access control by putting ``+'' in
saned.conf and use a line of the following form in /etc/inetd.conf
instead:
sane stream tcp nowait saned.saned /usr/sbin/tcpd saned
Note that both examples assume that there is a saned group and a saned
user. If you follow this example, please make sure that the access
permissions on the special device are set such that saned can access
the scanner (the program generally needs read and write access to scanner
devices).
If xinetd is installed on your system instead of inetd the following
example for xinetd.conf may be helpful:
# default: off
# description: The sane server accepts requests
# for network access to a local scanner via the
# network.
service sane
{
port = 6566
socket_type = stream
wait = no
user = saned
group = saned
server = /usr/local/sbin/saned
}
Finally, it is also necessary to add a line of the following form to
/etc/services:
sane 6566/tcp # SANE network scanner daemon
Note that port number 6566 has not been officially assigned to the SANE
network protocol and may thus change in the future.
In addition to the control connection (port 6566) saned also uses a
data connection. The port of this socket is selected by the operating
system and can't be specified by the user currently. This may be a
problem if the connection must go through a firewall (packet filter).
/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.
/etc/sane.d/saned.conf
Contains a list of hosts permitted to access local SANE devices
(see also description of SANE_CONFIG_DIR below).
/etc/sane.d/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 encryption if supported by the client.
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 /etc/sane.d. 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
SANE_CONFIG_DIR to "/tmp/config:" would result in directories
"tmp/config", ".", and "/etc/sane.d" being searched (in this
order).
sane(7), scanimage(1), xscanimage(1), xcam(1), sane-dll(5),
sane-net(5), sane-"backendname"(5)
http://home.nexgo.de/jochen.eisinger/saned/
David Mosberger
07 Jan 2002 saned(1)
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