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Configuration file reference

The configuration file is formatted in XML and subdivided in 4 sections:

  • Default options, shared among every device, user and service
  • Devices declaration and settings
  • Users declaration and settings
  • Services declaration and settings

The syntax is the following:

<configuration>
    <defaults>
        <!-- default options -->
    </defaults>

    <devices>
        <!-- devices definitions -->
    </devices>

    <users>
        <!-- users definitions -->
    </users>

    <services>
        <!-- services definitions -->
    </services>
</configuration>

Options

Name Type Default Description
enable Boolean true Enable pam_usb
debug Boolean false Enable debug messages
quiet Boolean false Quiet mode
color_log Boolean true Enable colored output
one_time_pad Boolean true Enable the use of one time pads
deny_remote Boolean true Deny access from remote host (ssh)
probe_timeout Time 10s Time to wait for the volume to be detected
pad_expiration Time 1h Time between pads regeneration
hostname String Computer's hostname Must be unique accross computers using the same device
system_pad_directory String .pamusb Relative path to the user's home used to store one time pads
device_pad_directory String .pamusb Relative path to the device used to store one time pads

Example:

<configuration>
    <defaults>
        <!-- Disable colored output by default -->
        <option name="color_log">false</option>
        <!-- Enable debug output -->
        <option name="debug">true</option>
    </defaults>

    <users>
        <user id="root">
            <!-- Enable colored output for user "root" -->
            <option name="color_log">true</option>
        </user>

        <user id="scox">
             <!-- Disable debug output for user "scox" -->
             <option name="debug">false</option>
        </user>
    </users>

    <devices>
        <device id="mydevice">
            <!-- Wait 15 seconds instead of the default 10 seconds for "mydevice" to be detected -->
            <option name="probe_timeout">15</option>
        </device>
    </devices>

    <services>
        <service id="su">
            <!-- Disable pam_usb for "su" ("su" will ask for a password as usual) -->
            <option name="enable">false<option>
       </service>
    </services>
</configuration>

Devices

Name Type Description Example
id Attribute Arbitrary device name MyDevice
vendor Element device's vendor name SanDisk Corp.
model Element device's model name Cruzer Titanium
serial Element serial number of the device SNDKXXXXXXXXXXXXXXXX
volume_uuid Element UUID of the device's volume used to store pads 6F6B-42FC

Example:

<device id="MyDevice">
    <vendor>SanDisk Corp.</vendor>
    <model>Cruzer Titanium</model>
    <serial>SNDKXXXXXXXXXXXXXXXX</serial>
    <volume_uuid>6F6B-42FC</volume_uuid>
</device>

Users

Name Type Description Example
id Attribute Login of the user root
device Element id of the device associated to the user MyDevice
agent Element Agent commands, for use with pamusb-agent

Example:

<user id="scox">
    <device>MyDevice</device>

    <!-- When the user "scox" removes the usb device, lock the screen and pause
    beep-media-player -->
    <agent event="lock">gnome-screensaver-command --lock</agent>
    <agent event="lock">beep-media-player --pause</agent>

    <!-- Resume operations when the usb device is plugged back and authenticated -->
    <agent event="unlock">gnome-screensaver-command --deactivate</agent>
    <agent event="unlock">beep-media-player --play</agent>
</user>

Services

Name Type Description Example
id Attribute Name of the service su

Example:

<service id="su">
    <!--
       Here you can put service specific options such as "enable", "debug" etc.
       See the options section of this document.
    -->
</service>

Location of the configuration file

By default, pam_usb.so and its tools will look for the configuration file at /etc/pamusb.conf.

If you want to use a different location, you will have to use the -c flag.

# /etc/pam.d/common-auth
auth    sufficient      pam_usb.so -c /some/other/path.conf
auth    required        pam_unix.so nullok_secure

You will also have to use the -c option when calling pam_usb's tools.

pamusb-agent -c /some/other/path.conf
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