Hardening DDMA Copy‑On‑Write exploit PoC.

[alor29]

Description:
This pull request adds simple safety checks to make the proof‑of‑concept more robust and less risky to run.

PID validation: Before, the program would try to inject into any process ID, including critical system processes. I added a guard so that very low PIDs (like 0–4) are rejected. This prevents accidental crashes or corruption of system processes.

Section size check: The exploit assumed the .text section of kernel32.dll always had enough space for shellcode. I added a check to make sure the section is at least 0x1000 bytes before attempting injection. This avoids writing into too small a section.

TLS address sanity check: The code used whatever address GetProcAddress returned for TlsGetValue. I added a guard to stop if the address is invalid. This prevents overwriting memory when the pointer is not safe.

Shellcode size validation: The exploit copied shellcode without checking if it fit. I added a check so that if the shellcode is larger than the allocated section, the program aborts instead of overflowing memory.