Error if allocated memory spans over the address 0x100000000 (4GB)

[tobias-loew]

FinalizeSections will fail if the allocated memory spans over the address 0x100000000 (4GB) since the addresses in the IMAGE_SECTION_HEADER are only 32-bit values.
I could fix it by putting the following code after the allocation of the variable "code":

#ifdef _WIN64
// check that memory-block does not span over the 4GB border
if(code < (LPVOID)0x100000000 && code + alignedImageSize >= (LPVOID)0x100000000)
{
auto old_code = code;
code = (unsigned char *)allocMemory(NULL,
alignedImageSize,
MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE,
userdata);
freeMemory(old_code, 0, MEM_RELEASE, userdata);
if(code == NULL) {
SetLastError(ERROR_OUTOFMEMORY);
return NULL;
}
}
#endif

[fancycode]

Hmm, that looks hacky ;-)

From reading the original code, is the problem that sectionData.address is wrong in line 280 in your case?
https://github.com/fancycode/MemoryModule/blob/master/MemoryModule.c#L280

Also which version/commit are you using?

[tobias-loew]

The problem is actually in line 295:
when the memory spans the 4 GB boundary the expression
(uintptr_t) sectionData.address + sectionData.size > (uintptr_t) alignedAddress
evaluates to true and thus the code from 297 to 303 the erroneously executed.

Please see my PR #64

PS:
I use memorymodule on a 64-bit machine to load like a 100 copies off the same dll, and everything works fine until I step over the 4 GB boundary

[tobias-loew]

You can force the crash by spefifying a load address in line 582 that is just below the 4GB boundary, such address + alignedImageSize is above 4GB

[tobias-loew]

I just figured out that the crash happens every-time the memory spans over A MULTIPLE of 4GB (obviously). My bad. I'll make a new pull request.

[ianhbell]

See #67