saned Man page

saned(8) SANE Scanner Access Now Easy saned(8)

NAME

saned – SANE network daemon

SYNOPSIS

saned [ -a [ username ] | -d [ n ] | -s [ n ] | -h ]

DESCRIPTION

saned is the SANE (Scanner Access Now Easy) daemon that allows remote
clients to access image acquisition devices available on the local
host.

OPTIONS

The -a flag requests that saned run in standalone daemon mode. In this
mode, saned will detach from the console and run in the background,
listening for incoming client connections; inetd is not required for
saned operations in this mode. If the optional username is given after
-a , saned will drop root privileges and run as this user (and group).

The -d and -s flags request that saned run in debug mode (as opposed to
inetd(8) daemon mode). In this mode, saned explicitly waits for a con‐
nection 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.

If saned is run from inetd, xinetd or systemd, no option can be given.

The -h flag displays a short help message.

CONFIGURATION
First and foremost: saned is not intended to be exposed to the internet
or other non-trusted networks. Make sure that access is limited by tcp‐
wrappers and/or a firewall setup. Don’t depend only on saned’s own
authentication. Don’t run saned as root if it’s not necessary. And do
not install saned as setuid root.

The saned.conf configuration file contains both options for the daemon
and the access list.

data_portrange = min_port – max_port
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 saned server is sitting behind a firewall. If that firewall
is a Linux machine, we strongly recommend using the Netfilter
nf_conntrack_sane module instead.

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 permit‐
ted. 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:

# Daemon options
data_portrange = 10000 – 10100
# Access list
scan-client.somedomain.firm
# this is a comment
192.168.0.1
192.168.2.12/29
[::1] [2001:db8:185e::42:12]/64

The case of the host names does not matter, so AHost.COM is considered
identical to ahost.com.

SERVER DAEMON CONFIGURATION
For saned to work properly in its default mode of operation, it is also
necessary to add the appropriate configuration for (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.

In the sections below the configuration for inetd, xinetd and systemd
are described in more detail.

For the configurations below it is necessary to add a line of the fol‐
lowing form to /etc/services:

sane-port 6566/tcp # SANE network scanner daemon

The official IANA short name for port 6566 is “sane-port”. The older
name “sane” is now deprecated.

INETD CONFIGURATION
It is required to add a single line to the inetd configuration file
(/etc/inetd.conf)

The configuration line normally looks like this:

sane-port 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-port stream tcp nowait saned.saned /usr/sbin/tcpd
/usr/sbin/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 scan‐
ner devices).

XINETD CONFIGURATION
If xinetd is installed on your system instead of inetd the following
example for /etc/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
{
port = 6566
socket_type = stream
wait = no
user = saned
group = saned
server = /usr/sbin/saned
}

SYSTEMD CONFIGURATION
for systemd we need to add 2 configuation files in /etc/systemd/system.

The first file we need to add here is called saned.socket. It shall
have the following contents:

[Unit] Description=saned incoming socket

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

[Install] WantedBy=sockets.target

The second file to be added is saned@.service with the following con‐
tents:

[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=/etc/sane.d SANE_DEBUG_DLL=255

Is you need to set an environment variable for saned like SANE_CON‐
FIG_DIR you will have to remove the # on the last line and set the
variable appropriately. Multiple variables can be set by separating
the assignments by spaces as shown in the example above.

Unlike (x)inetd systemd allows debugging output from backends set using
SANE_DEBUG_ to be captured. With the service unit as
described above, the debugging output is forwarded to the system log.

FILES
/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 hashing if supported by the client.

ENVIRONMENT
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 config‐
uration 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 sepa‐
rator 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).

SEE ALSO

sane(7), scanimage, xscanimage, xcam(1), sane-dll(5),
sane-net(5), sane-“backendname”(5)
http://www.penguin-breeder.org/?page=sane-net

AUTHOR

David Mosberger

20 Apr 2009 saned(8)