NAME
lockout - avoid slacking and impose productivity and discipline on
yourself
WARNING
This program is VERY DANGEROUS. If it fails, you may end up not
knowing the root password to your own computer (in which case you need
to boot into single-user mode). There are no known reports of this
actually happening, but we don’t know how stupid you are. Also, you
should probably not run this on a multi-user system.
SYNOPSIS
lockout lock HhMm │ Hh │ Mm
lockout lock HH:MM
lockout lock HH:MMam │ HH:MMpm
lockout lock HHam │ HHpm
lockout lock
lockout unlock [force]
lockout status
DESCRIPTION
Lockout is a tool that imposes discipline on you so that you get some
work done. For example, lockout can be used to install a firewall that
does not let you browse the Web. Lockout changes the root password for
a specified duration; this prevents you from secretly ripping down the
firewall and then browsing the Web anyway. In case of an emergency,
you can reboot your computer to undo the effects of lockout and to
restore the original root password.
Obviously, lockout lock and lockout unlock can only be run by root.
lockout status can be run by any user.
lockout without any parameters shows a brief help message.
lockout lock takes one optional parameter. If no parameter is given,
you are dropped in interactive mode and asked for the duration of the
lock or the time at which the lock should be lifted. You can also
supply this as a parameter on the command line. Lockout understands
various time formats. You can specify a delay, e.g., 3h (3 hours),
1h30m (1 hour and 30 minutes), or 90m (1 hour and 30 minutes), or you
can specify absolute time, e.g., 2pm, 2:30am, 15:30, etc. You will be
asked to confirm the time at which lockout will unlock your system. If
you type "yes", lockout executes /etc/lockout/lock.sh and changes the
root password to something completely random. /etc/lockout/lock.sh is
a shell script that you write. It takes measures to make sure you stop
slacking. For example, it could install a firewall that prevents
outgoing connections to port 80. See the "EXAMPLES" section below.
lockout unlock takes an optional force parameter. Without any
parameters, lockout lock will check whether it is time to unlock the
system and, if so, executes /etc/lockout/unlock.sh, which is a shell
script that you write. It should undo the effects of
/etc/lockout/lock.sh, executed when the system was locked. If you pass
the force parameter to lockout unlock, lockout will forcibly unlock
your system, whether it was really time for that or not. lockout
unlock should be called every minute by cron. See "CONFIGURATION".
lockout status will print out the time at which the system is going to
be unlocked.
CONFIGURATION
/etc/cron.d/lockout must contain the following two entries:
*/1 * * * * root /usr/bin/lockout unlock >/dev/null 2>&1
@reboot root /usr/bin/lockout unlock force >/dev/null 2>&1
The examples that follow assume you are using sudo(8) and you have a
file, /etc/lockout/sudoers.normal which is the normal /etc/sudoers
file, and /etc/lockout/sudoers.lock, which is the /etc/sudoers file
when lockout locks your computer. This example also assumes you are
using iptables(8). /var/lib/iptables/active should contain your
default firewall rules, and /var/lib/iptables/work should contain the
firewall rules that enforce discipline. See below for an example.
/etc/lock/lock.sh imposes discipline. For example:
#!/bin/sh
/etc/init.d/iptables load work
cp /etc/lockout/sudoers.lock /etc/sudoers
/etc/init.d/sudo stop
/etc/init.d/sudo start
/etc/lock/unlock.sh undoes these effects. For example:
#!/bin/sh
/etc/init.d/iptables restart
cp /etc/lockout/sudoers.normal /etc/sudoers
/etc/init.d/sudo stop
/etc/init.d/sudo start
Your /var/lib/iptables/work may look something like this:
*filter
:INPUT ACCEPT [1047:99548]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1104:120792]
# allow incoming packets from localhost, ntp,
# and existing connections
-A INPUT -i lo -j ACCEPT
-A INPUT -p udp -m udp --source-port ntp -m state --state ESTABLISHED -j ACCEPT
-A INPUT -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp -j DROP
-A INPUT -p udp -j DROP
# allow outgoing connections for email and DNS
-A OUTPUT -d 127.0.0.1/8 -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport smtp -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport domain -j ACCEPT
-A OUTPUT -p udp -m udp --dport domain -j ACCEPT
-A OUTPUT -j DROP
COMMIT
EXAMPLES
lockout lock 2h30m [locks out for 2h and 30m]
lockout lock 90m [locks out for 1h and 30m]
lockout lock 3pm [locks out until 3pm]
lockout lock 3:20am [locks out until 3:20am]
lockout lock 15:20 [locks out until 3:20pm]
lockout status [shows when the system is going to be unlocked]
FILES
/etc/lockout/lock.sh: executed when running lockout lock
/etc/lockout/unlock.sh: executed when running lockout unlock
SEE ALSO
usermod(8), iptables(8), passwd(1), cron(8), crontab(1)
BUGS
Arguably, a program that changes the root password to something random
with the possibility of never recovering the original password might be
considered a bug by itself. Other than that, no known bugs.
AUTHOR
Thomer M. Gil, http://thomer.com/lockout/