YubiKey lock screen

What

I'm trying to make my fedora 17 ( gnome3 ) desktop lock the screen when it sees my yubikey removed from the usb slot.

HOW

Get the serial, idVendor, idProduct of the thing.

udevadm info -a -p $(udevadm info -q path -n /dev/hidraw0)

Create a /etc/udev/rules.d/85-screen-lock-toggle.rules

SUBSYSTEM=="usb", ACTION=="remove", ENV{ID_VENDOR_ID}=="1050", ENV{ID_SERIAL_SHORT}=="0001121136", RUN+="/usr/local/bin/gnome-lock enable"
SUBSYSTEM=="usb", ACTION=="add", ENV{ID_VENDOR_ID}=="1050", ENV{ID_MODEL_ID}=="0010", RUN+="/usr/local/bin/gnome-lock disable"

Also you should probably reload the rules:

udevadm control --reload-rules

And you should create the 2 scripts (you'll probably have to comment out default requirretty in /etc/sudoers) :

~# cat /usr/local/bin/gnome-lock
#!/bin/bash
log="/tmp/yubi_lock_log"
echo "$(date) $(whoami) '$0' '$1'" >> ${log}

user=`ps aux | grep gnome-screensaver | head -n 1 | awk '{print $1}'`
export DISPLAY=":0"
if [ "$1" == "enable" ]
then
    	if [ -n ${user} -a "$(grep -c ${user}:${ID_SERIAL_SHORT} /etc/yubikey_decmappings)" == "1" ]
        then
            	sudo -u ${user} /usr/bin/gnome-screensaver-command -l >> ${log} 2>&1
        fi
else
    	if [ -n ${user} -a "$(grep -c ${user}:000$(ykinfo -q -s) /etc/yubikey_decmappings)" == "1" ]
        then
            	sudo -u ${user} /usr/bin/gnome-screensaver-command -d >> ${log} 2>&1
        fi
fi

Your /etc/yubikey_decmappings should contain user:000key, padding with 000(you can see that in env) (which key should be able to unlock what login if in multiple desktop environment )

ISSUES

On an arch environment it has been said you need some other exports for this to work...

GNOME_SCREENSAVER_PROC=`ps xa | grep gnome-screensaver | head -n 1 | awk '{print $1}'`
export `grep -z DBUS_SESSION_BUS_ADDRESS /proc/$GNOME_SCREENSAVER_PROC/environ`

Also, you could probably use dbus to do the job for locking/unlocking

sudo -u ${user} dbus-send --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.SetActive boolean:false # for unlock
sudo -u ${user} dbus-send --type=method_call --dest=org.gnome.ScreenSaver /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock # for lock