run program at failed login

themanwhowas · 06-02-2014, 07:28 AM

Hello

Fedora 19 KDE 4

How can i run a program when a user login fails due to incorrect password? google leads me toward PAM but is there an easier way? if not can anyone point me to a PAM newbie guide as I've never done anything with that before.

The program I want to run is just a simple bash script

Thanks

Pearlseattle · 06-02-2014, 04:33 PM

Hi

Very intersting, but not sure how to do it.

This is some kind of low-level change which might make your system not able to boot => first ensure that you have an alternative way of booting your PC (e.g. using a cd-rom)

In my case (Gentoo Linux without graphical login), the login is controlled by the configuration found in "/etc/inittab:

Code:

# TERMINALS
c1:12345:respawn:/sbin/agetty --noclear 38400 tty1 linux
c2:2345:respawn:/sbin/agetty --noclear 38400 tty2 linux
c3:2345:respawn:/sbin/agetty --noclear 38400 tty3 linux
c4:2345:respawn:/sbin/agetty --noclear 38400 tty4 linux
c5:2345:respawn:/sbin/agetty --noclear 38400 tty5 linux
c6:2345:respawn:/sbin/agetty --noclear 38400 tty6 linux

Maybe you could substitute the text saying e.g. "/sbin/agetty --noclear 38400 ttyXXX linux" with your own script "/my/own/scriptXXX.sh" and in "scriptXXX.sh" write something like...

Code:

/sbin/agetty --noclear 38400 ttyXXX linux || echo somefailedlogin_on_XXX >> /tmp/nosypeople.txt

...which would execute the same exact original command but additionally run the "echo" command (for testing purposes - once you have that working you can run anything) only in case of a failure.

Again: if you screw up with "inittab" you'll definitely end up not being able to login at all => ensure that you have a way to modify that file without relying on your HDD (e.g. booting from cd-rom + mounting your root partition + edit that file).

Have fun