feat(soyuz): 🚀

.gitignore

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+# IDE
+/.idea/
+
+# CMake
+/cmake-build-debug/
+/build/

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.20)
+project(soyuz)
+
+add_subdirectory(${PROJECT_NAME})

README.rst

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+🚀 Soyuz
+=======
+
+Soyuz has one simple purpose; listen for incoming Discord RPC requests from
+Lunar Client and block them!
+
+.. raw:: html
+
+  <a href="https://github.com/fuwn/soyuz">
+    <img
+      src="http://www.spacesafetymagazine.com/wp-content/uploads/2014/08/early-soyuz-capsule.gif"
+      alt="Soyuz"
+      width="220">
+  </a>
+
+Limitations
+-----------
+
+- Windows only
+
+Soon to come
+------------
+
+- Tray support
+- "Startup" support
+
+License
+-------
+
+`GNU General Public License v3.0 <./LICENSE>`_

include/soyuz/library.hh

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+// Copyright (C) 2021-2021 Fuwn
+// SPDX-License-Identifier: GPL-3.0-only
+
+#ifndef SOYUZ_LIBRARY_HH
+#define SOYUZ_LIBRARY_HH
+
+#pragma once
+
+#include <Windows.h>
+
+#define NT_SUCCESS(status) (status >= 0)
+#define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS)0xC0000004L)
+
+enum PROCESSINFOCLASS {
+  ProcessHandleInformation = 51
+};
+
+typedef struct _PROCESS_HANDLE_TABLE_ENTRY_INFO {
+  HANDLE HandleValue;
+  ULONG_PTR HandleCount;
+  ULONG_PTR PointerCount;
+  ULONG GrantedAccess;
+  ULONG ObjectTypeIndex;
+  ULONG HandleAttributes;
+  ULONG Reserved;
+} PROCESS_HANDLE_TABLE_ENTRY_INFO, * PPROCESS_HANDLE_TABLE_ENTRY_INFO;
+
+typedef struct _PROCESS_HANDLE_SNAPSHOT_INFORMATION {
+  ULONG_PTR NumberOfHandles;
+  ULONG_PTR Reserved;
+  PROCESS_HANDLE_TABLE_ENTRY_INFO Handles[1];
+} PROCESS_HANDLE_SNAPSHOT_INFORMATION, * PPROCESS_HANDLE_SNAPSHOT_INFORMATION;
+
+extern "C" NTSTATUS NTAPI NtQueryInformationProcess(
+  _In_ HANDLE ProcessHandle,
+  _In_ PROCESSINFOCLASS ProcessInformationClass,
+  _Out_writes_bytes_(ProcessInformationLength) PVOID ProcessInformation,
+  _In_ ULONG ProcessInformationLength,
+  _Out_opt_ PULONG ReturnLength
+);
+
+typedef enum _OBJECT_INFORMATION_CLASS {
+  ObjectNameInformation = 1
+} OBJECT_INFORMATION_CLASS;
+
+typedef struct _UNICODE_STRING {
+  USHORT Length;
+  USHORT MaximumLength;
+  PWSTR  Buffer;
+} UNICODE_STRING;
+
+typedef struct _OBJECT_NAME_INFORMATION {
+  UNICODE_STRING Name;
+} OBJECT_NAME_INFORMATION, * POBJECT_NAME_INFORMATION;
+
+extern "C" NTSTATUS NTAPI NtQueryObject(
+  _In_opt_ HANDLE Handle,
+  _In_ OBJECT_INFORMATION_CLASS ObjectInformationClass,
+  _Out_writes_bytes_opt_(ObjectInformationLength) PVOID ObjectInformation,
+  _In_ ULONG ObjectInformationLength,
+  _Out_opt_ PULONG ReturnLength
+);
+
+static auto enum_windows_proc(HWND hwnd, LPARAM lparam) -> BOOL;
+auto find_lunar() -> DWORD;
+auto delete_handle(DWORD pid) -> int;
+
+#endif //SOYUZ_LIBRARY_HH

include/soyuz/soyuz.hh

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+// Copyright (C) 2021-2021 Fuwn
+// SPDX-License-Identifier: GPL-3.0-only
+
+#ifndef SOYUZ_SOYUZ_HH
+#define SOYUZ_SOYUZ_HH
+
+#pragma once
+
+#define LUNAR_WINDOW_NAME_BASE "Lunar Client ("
+#define DISCORD_IPC_NAMED_PIPE_NAME L"\\Device\\NamedPipe\\discord-ipc-0"
+
+#endif //SOYUZ_SOYUZ_HH

soyuz/CMakeLists.txt

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+add_executable(${PROJECT_NAME}
+  library.cc
+  soyuz.cc
+)
+
+target_include_directories(${PROJECT_NAME} PRIVATE ${PROJECT_SOURCE_DIR}/include)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES
+  CXX_STANDARD 20
+  CXX_STANDARD_REQUIRED ON
+  CMAKE_CXX_EXTENSIONS OFF
+)
+target_compile_features(${PROJECT_NAME} PUBLIC
+  cxx_std_20
+  cxx_return_type_deduction
+)
+
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+  target_compile_options(${PROJECT_NAME} PUBLIC -W3)
+else()
+  target_compile_options(${PROJECT_NAME} PUBLIC -Wall)
+endif()
+add_compile_options(-stdlib=libc++)

soyuz/library.cc

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+// Copyright (C) 2021-2021 Fuwn
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include <cstdio>
+#include <memory>
+#include <string>
+#include <Windows.h>
+
+#include "soyuz/library.hh"
+#include "soyuz/soyuz.hh"
+
+static auto enum_windows_proc(HWND hwnd, LPARAM lparam) -> BOOL {
+  int length = GetWindowTextLength(hwnd);
+  auto title = new CHAR[length + 1];
+  GetWindowText(hwnd, title, length);
+
+  if (strstr(title, LUNAR_WINDOW_NAME_BASE)) {
+    *((HWND*)lparam) = hwnd;
+
+    delete[] title;
+
+    return FALSE;
+  }
+
+  delete[] title;
+
+  return TRUE;
+}
+
+auto find_lunar() -> DWORD {
+  HWND window = nullptr;
+  EnumWindows(enum_windows_proc, (LPARAM)&window);
+
+  int length = GetWindowTextLength(window);
+  auto title = new CHAR[length + 1];
+  GetWindowText(window, title, length);
+
+  DWORD pid;
+  GetWindowThreadProcessId(window, &pid);
+  return pid;
+}
+
+auto delete_handle(DWORD pid) -> int {
+  HANDLE lunar = OpenProcess(
+    PROCESS_QUERY_INFORMATION | PROCESS_DUP_HANDLE,
+    FALSE,
+    pid
+  );
+  if (!lunar) {
+    printf("could not open handle to lunar client: %lu\n", GetLastError());
+
+    return 1;
+  }
+
+  ULONG size = 1 << 10;
+  std::unique_ptr<BYTE[]> buffer;
+  for (;;) {
+    buffer = std::make_unique<BYTE[]>(size);
+
+    NTSTATUS status = NtQueryInformationProcess(
+      lunar,
+      ProcessHandleInformation,
+      buffer.get(),
+      size,
+      &size
+    );
+
+    if (NT_SUCCESS(status)) { break; }
+    if (status == STATUS_INFO_LENGTH_MISMATCH) { size += 1 << 10; continue; }
+
+    printf("could not enumerate handle\n");
+
+    return 1;
+  }
+
+  auto *info = reinterpret_cast<PROCESS_HANDLE_SNAPSHOT_INFORMATION*>(buffer.get());
+  for (ULONG i = 0; i < info->NumberOfHandles; ++i) {
+    HANDLE h = info->Handles[i].HandleValue;
+    HANDLE target;
+    if (!DuplicateHandle(
+      lunar,
+      h,
+      GetCurrentProcess(),
+      &target,
+      0,
+      FALSE,
+      DUPLICATE_SAME_ACCESS
+    )) { continue; }
+
+    BYTE name_buffer[1 << 10];
+    NTSTATUS status = NtQueryObject(
+      target,
+      ObjectNameInformation,
+      name_buffer,
+      sizeof(name_buffer),
+      nullptr
+    );
+    CloseHandle(target);
+    if (!NT_SUCCESS(status)) { continue; }
+
+    WCHAR target_name[256];
+    DWORD session_id;
+    ProcessIdToSessionId(pid, &session_id);
+    swprintf_s(target_name, DISCORD_IPC_NAMED_PIPE_NAME);
+    size_t length = wcslen(target_name);
+
+    auto *name = reinterpret_cast<UNICODE_STRING*>(name_buffer);
+    if (name->Buffer && _wcsnicmp(name->Buffer, target_name, length) == 0) {
+      printf("found lunar client's discord ipc named pipe\n");
+
+      DuplicateHandle(
+        lunar,
+        h,
+        GetCurrentProcess(),
+        &target,
+
+        0,
+        FALSE,
+        DUPLICATE_CLOSE_SOURCE
+      );
+      CloseHandle(target);
+
+      printf("closed lunar client's discord ipc named pipe\n");
+
+      return 0;
+    }
+  }
+
+  return 0;
+}

soyuz/soyuz.cc

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+// Copyright (C) 2021-2021 Fuwn
+// SPDX-License-Identifier: GPL-3.0-only
+
+#pragma comment(lib, "ntdll.lib")
+
+#include <cstdio>
+#include <Windows.h>
+
+#include "soyuz/library.hh"
+
+auto main() -> int {
+  DWORD pid = find_lunar();
+  if (pid == 0 || pid == 3435973836) {
+    printf("could not locate lunar client\n");
+
+    return 1;
+  }
+  printf("located lunar client: %lu\n\n", pid);
+
+  for (;;) {
+    if (delete_handle(pid) == 1) {
+      printf("unable to close lunar client's discord ipc named pipe\n");
+    }
+  }
+
+  return 0;
+}