Putting rickrolling in kernel space
Kernelroll is a linux kernel module for advanced rickrolling.
It works by patching the open() system call to open a specified music file instead of other music files. Currently, it only checks if the file extension "mp3" is present and calls the original open() with the supplied path instead.
WARNING: There is probably a performance penalty and your kernel might crash at a very inappropriate time and cause data loss! You are responsible for the code you load into your kernel!
But most probably, it will be alright! ;)
You need the address of sys_call_table in your kernel. Use
$ grep sys_call_table /boot/System.map-3.0.0-1-amd64 ffffffff81400300 R sys_call_table
on the respective System.map of your kernel to find out the address
Now fire up kernelroll.c and add yours:
void **sys_call_table = (void **)0xffffffff81400300;
This will probably be simplified in the future, but as sys_call_table isn't exported anymore in 2.6 kernels, we have to use some tricks.
$ insmod kernelroll.ko rollfile=/path/to/rickroll.mp3
Fire up a music player of your choice, play a song and consider yourself kernelrolled. ;)