Why ReadProcessMemory error (0xC0000005)

[aleaforny]

Please note I'm referring to this issue: #1570

I'm getting 0xC0000005 while attempting to use ReadProcessMemory, nevertheless it's not happening while using the library with ctypes (proving that it's not an access violation issue).

FYI, I'm attempting to read an integer value (from process with PID 18896)

The following codes produces 0xC0000005:

process = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS, False, 18896)
print(win32process.ReadProcessMemory(process, 0x20c6a34aa30, sys.getsizeof(wintypes.INT())))

When the following codes works as expected:

process = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS, False, 18896)

ReadProcessMemory = ctypes.WinDLL('kernel32', use_last_error=True).ReadProcessMemory
ReadProcessMemory.argtypes = [wintypes.HANDLE, wintypes.LPCVOID, wintypes.LPVOID, ctypes.c_size_t, ctypes.POINTER(ctypes.c_size_t)]
ReadProcessMemory.restype = wintypes.BOOL

int_buffer = 0

if ReadProcessMemory(process.handle, 0x20c6a34aa30, id(int_buffer), sys.getsizeof(wintypes.INT()), None):
    print("int_buffer= {}".format(int_buffer))

Any idea?

Thanks

[mhammond]

That's odd - if you can come up with a way for me to repro it I'm happy to see what I can find.

[aleaforny]

Thanks @mhammond

Here the program I run where I attempt to get int_content:
https://pastebin.com/Q6wic9pi

Here the code which is working (pywin32 + ctypes):
(https://pastebin.com/Xgtf0yk2)

Here the code resulting in 0xC0000005 (pywin32 only):
https://pastebin.com/HukyEYXt

FYI, I'm running all the programs with the same privileges, under Windows 10 64bits (winver 1909), UAC enabled.

Hope this can help!

[mhammond]

Thanks - silly mistake in win32process.i - will be fixed in the next release.

[aleaforny]

Awesome, thanks @mhammond !