New subject: [Bug 56357] Zero sized writes using WriteProcessMemory succeed on Windows, but fail on Wine.

23 Feb 2024


      https://bugs.winehq.org/show_bug.cgi?id=56357
Bug ID: 56357
           Summary: Zero sized writes using WriteProcessMemory succeed on
                    Windows, but fail on Wine. testcase source
           Product: Wine
           Version: 9.2
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: wine-bugs@winehq.org
          Reporter: admin@sewer56.dev
      Distribution: ---
Created attachment 76082
  --> https://bugs.winehq.org/attachment.cgi?id=76082
Precompiled sample C program.
[ testcase source ]
Zero sized writes using WriteProcessMemory succeed on Windows, but fail on
Wine.
Build the following program:
```c
#include <windows.h>
#include <stdio.h>
int main() {
    // Allocate a buffer in memory
    char* buffer = (char*) VirtualAlloc(NULL, 1024, MEM_COMMIT | MEM_RESERVE,
PAGE_READWRITE);
    if (buffer == NULL) {
        printf("Memory allocation failed\n");
        return 1;
    }
// Sample data to write (not actually used due to 0-byte length)
    const char* data = "Sample data";
    SIZE_T writtenBytes = 0;
// Get a handle to the current process
    HANDLE processHandle = GetCurrentProcess();
// Attempt to write memory with 0 byte length
    BOOL result = WriteProcessMemory(processHandle, buffer, data, 0,
&writtenBytes);
if (result == FALSE) {
        printf("WriteProcessMemory failed: %lu\n", GetLastError());
    } else {
        printf("WriteProcessMemory succeeded, but 0 bytes were written.\n");
    }
VirtualFree(buffer, 0, MEM_RELEASE);
    return 0;
}
```
Commandline:
```
x86_64-w64-mingw32-gcc write_process_memory.c -o write_process_memory.exe
-lkernel32
```
When running on Linux, this prints `WriteProcessMemory failed: 87`.
When running on Windows, this succeeds `WriteProcessMemory succeeded, but 0
bytes were written`.
Tested on x86_64 Archlinux using latest git version of Wine
(wine-9.2-286-g232b18d820e).
-----------
Extra Notes:
I encountered this bug while unit testing a Rust DLL Injection library against
Wine: https://github.com/OpenByteDev/dll-syringe/pull/19
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[Bug 56357] New: Zero sized writes using WriteProcessMemory succeed on Windows, but fail on Wine. testcase source