Memory pointer truncation on 64bit systems

If I understand correctly Defense+ now include the Comodo Memory Firewall. This bug report is really for the last version of the memory firewall, but since the bug has been in the memory firewall for over a year I doubt it has been fixed.

The memory firewall has for all releases I’ve tested had a bug where all memory pointers in the patched API calls are truncated to 32bit causing applications trash their own memory and also causing the heap list to be corrupted (failing memory allocations) when the application tries to allocate virtual memory beyond the 4GB barrier. That doesn’t mean that the application is really using 4GB, but just generating a pointer beyond that point.

Typically this causes problem with Mozilla Firefox which is very good on allocating memory. It starts to behave strange with corrupted pages when memory usage gets near 2GB.

Security software is rarely longlived on my system as most non-Microsoft (also called third party) software tend to BSOD or leak memory when under high pressure. So this was just another application confirming that writing security software isn’t an easy task.

My configuration:
Window Vista x64 Business
AMD Phenom II X4 940 @ 3.0GHz
8 GB of RAM (+16 GB page file)
Administrator account with UAC enabled