Repository navigation
Error if allocated memory spans over the address 0x100000000 (4GB) #63
Description
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
Activity
fancycode commentedon May 11, 2017
Hmm, that looks hacky ;-)
From reading the original code, is the problem that
sectionData.addressis 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 commentedon May 11, 2017
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 commentedon May 11, 2017
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 commentedon May 12, 2017
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 commentedon Aug 2, 2017
See #67
Prevent memory of library from spanning over 4GB bounaries.