NULLDEREF -- A module for playing with kernel NULL pointer dereferences

BUILDING This module should build against any remotely recent 2.6 kernel. To build, you'll need the kernel headers for your kernel installed. On Debian or Ubuntu, try:

apt-get install linux-headers-$(uname -r)

on Fedora, try:

yum install kernel-devel

Once you've got those, just run 'make' to produce a 'nullderef.ko' file.

USING

nullderef uses sysfs to export its hooks. Simply

insmod nullderef.ko

You shuld now have a /sys/module/nullderef/parameters/ directory, containing two files, "read", and "call".

Reading from either of these files will result in a NULL pointer dereference in the kernel. "read" will simply try to read a NULL pointer. "call" will read a function pointer from the NULL address, and then attempt to call through the resulting pointer.

Once you're done crashing your kernel, if your machine is still stable, you can remove the module using:

rmmod nullderef