> Tejun's example program digs around in the target's address space for a nice bit of memory which has execute permission; the contents of that memory are saved and replaced by his "parasite" code.
I covered this technique and its limitations in my Defcon 19 presentation. I created a project called libhijack that allows injection of arbitrary code into new memory mappings. I have a feeling libhijack will get much more powerful with PTRACE_SEIZE.
I'm curious why Linux developers don't implement a DTrace clone. PTrace should die a horrible death.