Question

I can use GetModuleHandle to get its base offset, but I also need to know the size of the code segment of the DLL or EXE. For example, I need to estimate nSize in this code:

char aCrashSignatureBytesAtEIP[] = { 0x87, 0x12, 0x00, ... };
char* pBaseOffset = (char*) GetModuleHandle(NULL);
int nSize = ???;
for (int i = 0; i<nSize; i++)
    if (!memcmp(&pBaseOffset[i], aCrashSignatureBytesAtEIP, sizeof(aCrashSignatureBytesAtEIP)))
    {
        printf("Crash signature found at offset %p", &pBaseOffset[i]);
    }

Answer 1

PSAPI gets you this: GetModuleInformation function returns you MODULEINFO structure with both base address and size of the image.

typedef struct _MODULEINFO {
  LPVOID lpBaseOfDll;
  DWORD  SizeOfImage;
  LPVOID EntryPoint;
} MODULEINFO, *LPMODULEINFO;