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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "mozilla/WindowsMsctfInitialization.h"
#include <windows.h>
#include "mozilla/NativeNt.h"
#include "mozilla/WindowsVersion.h"
#include "nsWindowsDllInterceptor.h"
namespace mozilla {
#if defined(_M_IX86) || defined(_M_X64)
// Starting with Windows 11 22H2 (10.0.22621.*), msctf.dll uses a new
// convention for the lParam argument of TF_Notify when uMsg is 0x20000. It now
// expects a pointer to a structure similar to LPARAM20000 described below,
// where a scalar value was used before. We convert the value forwarded by
// ZoneAlarm Anti-Keylogger to the new convention, if we detect that it is
struct LPARAM20000 {
uintptr_t Reserved1; // Not used
LPARAM LegacyValue; // This value used to be sent as lParam directly
uintptr_t Reserved2; // Used as a boolean (though never saw it set to true)
};
static WindowsDllInterceptor MsctfIntercept;
typedef uintptr_t(WINAPI* TF_Notify_func)(UINT uMsg, WPARAM wParam,
LPARAM lParam);
static WindowsDllInterceptor::FuncHookType<TF_Notify_func> stub_TF_Notify;
uintptr_t WINAPI patched_TF_Notify(UINT uMsg, WPARAM wParam, LPARAM lParam) {
// Only convert to the new convention if we detect a problem with the lParam
if (uMsg == 0x20000 &&
IsBadReadPtr(reinterpret_cast<void*>(lParam), sizeof(LPARAM20000))) {
// Using a pointer to stack as lParam is fine here: when observing calls
// that originate from Microsoft code, pointers to stack are used as well
LPARAM20000 lParamWithNewConvention{
.Reserved1 = 0,
.LegacyValue = lParam,
.Reserved2 = 0,
};
return stub_TF_Notify(uMsg, wParam,
reinterpret_cast<LPARAM>(&lParamWithNewConvention));
}
return stub_TF_Notify(uMsg, wParam, lParam);
}
bool WindowsMsctfInitialization() {
HMODULE icsak = ::GetModuleHandleW(L"icsak.dll");
if (!icsak) {
return true;
}
// Only proceed if msctf.dll uses the new lParam convention
if (!IsWin1122H2OrLater()) {
return true;
}
// Only proceed if icsak.dll is in version 1.5.393.2181 or older
nt::PEHeaders icsakHeaders{icsak};
uint64_t icsakVersion{};
if (!icsakHeaders || !icsakHeaders.GetVersionInfo(icsakVersion) ||
icsakVersion > 0x0001000501890885) {
return true;
}
// Apply our hook to fix messages using the old lParam convention
MsctfIntercept.Init(L"msctf.dll");
return stub_TF_Notify.Set(MsctfIntercept, "TF_Notify", &patched_TF_Notify);
}
#endif // _M_IX86 || _M_X64
} // namespace mozilla