When Memory Injection Sucks

Hi Folks,
during last few days I utilized a self-made tool to inject shellcode into process. I must be sincere.. it has been a while since I didn’t use it … maybe a year ? But it always worked great. I injected tons of shellcode on processes, at the beginning for studying (aka homework) and then for research purposes (aka for work). Well, today on BackTrack 4 it doesn’t work anymore. That surprised me.

The script uses ptrace() API, and like Malaria or shellInjector writes back to IP the entire shellcode. So far I have no idea what happened and why it wont work anymore. The displayed error is: POKETEXT Input/Output. I attache here the screenshot of the issue.

Suggestions ? Someone know what happens ? Maybe a kernel restriction ? Please leave a comment if you know what changed during last year :D. thank you .