Linux Kernel Hacking

2.0: Loading a Kernel Module from Memory (Kpatching chown)

Patch the kernel with a single executable!

To use:

• Set up kpatch following these instructions.
• Build the patch with kpatch-build -t vmlinux -v /lib/debug/boot/vmlinux-<KERNEL>-generic chown.patch
• Remove the - from the filename (C doesn't like it in variable names)
  • mv livepatch-chown.ko livepatch_chown.ko
• Build the loader with make
• Execute as root with sudo ./load
• chown a file, e.g. chown vagrant:vagrant chown.patch
• Check output in kernel buffer with dmesg
• Unload with echo 0 | sudo tee /sys/kernel/livepatch/chown/enabled && sudo rmmod chown