Bug 1838138: Remove InSendMessageEx hack. r=nlapre

This was only necessary when we had cross-process COM proxies for accessibility.

Differential Revision: https://phabricator.services.mozilla.com/D180776
This commit is contained in:
James Teh 2023-06-14 00:38:57 +00:00
Родитель f4b891103c
Коммит c1a2fd8cdb
1 изменённых файлов: 0 добавлений и 105 удалений

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@ -9,11 +9,9 @@
#include "mozilla/WindowsVersion.h"
#include "mozilla/WinHeaderOnlyUtils.h"
#include "mozilla/StaticPrefs_accessibility.h"
#include "nsExceptionHandler.h"
#include "nsIXULRuntime.h"
#include "nsPrintfCString.h"
#include "nsUnicharUtils.h"
#include "nsWindowsDllInterceptor.h"
#include "nsWinUtils.h"
#include "Statistics.h"
#include "AccessibleWrap.h"
@ -47,89 +45,6 @@ bool Compatibility::IsModuleVersionLessThan(HMODULE aModuleHandle,
// Compatibility
////////////////////////////////////////////////////////////////////////////////
static WindowsDllInterceptor sUser32Interceptor;
static WindowsDllInterceptor::FuncHookType<decltype(&InSendMessageEx)>
sInSendMessageExStub;
static bool sInSendMessageExHackEnabled = false;
static PVOID sVectoredExceptionHandler = nullptr;
#if defined(_MSC_VER)
# include <intrin.h>
# pragma intrinsic(_ReturnAddress)
# define RETURN_ADDRESS() _ReturnAddress()
#elif defined(__GNUC__) || defined(__clang__)
# define RETURN_ADDRESS() \
__builtin_extract_return_addr(__builtin_return_address(0))
#endif
static inline bool IsCurrentThreadInBlockingMessageSend(
const DWORD aStateBits) {
// From the MSDN docs for InSendMessageEx
return (aStateBits & (ISMEX_REPLIED | ISMEX_SEND)) == ISMEX_SEND;
}
/**
* COM assumes that if you're invoking a proxy from an STA thread while
* InSendMessageEx reports that the calling thread is blocked, that you'll
* deadlock your own process. It returns the RPC_E_CANTCALLOUT_ININPUTSYNCCALL
* error code. This is not actually true in our case: we are calling into
* the multithreaded apartment via ALPC. In this hook, we check to see if the
* caller is COM, and if so, we lie to it.
*
* This hack is necessary for ATs who invoke COM proxies from within
* WH_CALLWNDPROC hooks, WinEvent hooks, or a WndProc handling a sent
* (as opposed to posted) message.
*/
static DWORD WINAPI InSendMessageExHook(LPVOID lpReserved) {
MOZ_ASSERT(XRE_IsParentProcess());
DWORD result = sInSendMessageExStub(lpReserved);
if (NS_IsMainThread() && sInSendMessageExHackEnabled &&
IsCurrentThreadInBlockingMessageSend(result)) {
// We want to take a strong reference to the dll so that it is never
// unloaded/reloaded from this point forward, hence we use LoadLibrary
// and not GetModuleHandle.
static const HMODULE comModule = []() -> HMODULE {
HMODULE module = LoadLibraryW(L"combase.dll");
if (!module) {
// combase is not present on Windows 7, so we fall back to ole32 there
module = LoadLibraryW(L"ole32.dll");
}
return module;
}();
MOZ_ASSERT(comModule);
if (!comModule) {
return result;
}
// Check if InSendMessageEx is being called from code within comModule
HMODULE callingModule;
if (GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
reinterpret_cast<LPCWSTR>(RETURN_ADDRESS()),
&callingModule) &&
callingModule == comModule) {
result = ISMEX_NOTIFY;
}
}
return result;
}
static LONG CALLBACK
DetectInSendMessageExCompat(PEXCEPTION_POINTERS aExceptionInfo) {
DWORD exceptionCode = aExceptionInfo->ExceptionRecord->ExceptionCode;
if (exceptionCode == static_cast<DWORD>(RPC_E_CANTCALLOUT_ININPUTSYNCCALL) &&
NS_IsMainThread()) {
sInSendMessageExHackEnabled = true;
// We don't need this exception handler anymore, so remove it
if (RemoveVectoredExceptionHandler(sVectoredExceptionHandler)) {
sVectoredExceptionHandler = nullptr;
}
}
return EXCEPTION_CONTINUE_SEARCH;
}
uint32_t Compatibility::sConsumers = Compatibility::UNKNOWN;
/**
@ -206,26 +121,6 @@ void Compatibility::Init() {
if (!Preferences::HasUserValue("browser.ctrlTab.disallowForScreenReaders"))
Preferences::SetBool("browser.ctrlTab.disallowForScreenReaders", true);
}
// If we have a consumer who is not NVDA, we enable detection for the
// InSendMessageEx compatibility hack. NVDA does not require this.
// We also skip UIA, as we see crashes there.
if ((sConsumers & (~(UIAUTOMATION | NVDA))) && BrowserTabsRemoteAutostart()) {
sUser32Interceptor.Init("user32.dll");
sInSendMessageExStub.Set(sUser32Interceptor, "InSendMessageEx",
&InSendMessageExHook);
// The vectored exception handler allows us to catch exceptions ahead of any
// SEH handlers.
if (!sVectoredExceptionHandler) {
// We need to let ASan's ShadowExceptionHandler remain in the firstHandler
// position, otherwise we'll get infinite recursion when our handler
// faults on shadow memory.
const ULONG firstHandler = FALSE;
sVectoredExceptionHandler = AddVectoredExceptionHandler(
firstHandler, &DetectInSendMessageExCompat);
}
}
}
// static