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//===-- asan_win.cpp ------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Windows-specific details.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_WINDOWS
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdlib.h>
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_report.h"
#include "asan_stack.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_mutex.h"
#include "sanitizer_common/sanitizer_win.h"
#include "sanitizer_common/sanitizer_win_defs.h"
using namespace __asan;
extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE
int __asan_should_detect_stack_use_after_return() {
__asan_init();
return __asan_option_detect_stack_use_after_return;
}
SANITIZER_INTERFACE_ATTRIBUTE
uptr __asan_get_shadow_memory_dynamic_address() {
__asan_init();
return __asan_shadow_memory_dynamic_address;
}
} // extern "C"
// ---------------------- Windows-specific interceptors ---------------- {{{
static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler;
extern "C" SANITIZER_INTERFACE_ATTRIBUTE
long __asan_unhandled_exception_filter(EXCEPTION_POINTERS *info) {
EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
CONTEXT *context = info->ContextRecord;
// FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
SignalContext sig(exception_record, context);
ReportDeadlySignal(sig);
UNREACHABLE("returned from reporting deadly signal");
}
// Wrapper SEH Handler. If the exception should be handled by asan, we call
// __asan_unhandled_exception_filter, otherwise, we execute the user provided
// exception handler or the default.
static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
DWORD exception_code = info->ExceptionRecord->ExceptionCode;
if (__sanitizer::IsHandledDeadlyException(exception_code))
return __asan_unhandled_exception_filter(info);
if (user_seh_handler)
return user_seh_handler(info);
// Bubble out to the default exception filter.
if (default_seh_handler)
return default_seh_handler(info);
return EXCEPTION_CONTINUE_SEARCH;
}
INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER, SetUnhandledExceptionFilter,
LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter) {
CHECK(REAL(SetUnhandledExceptionFilter));
if (ExceptionFilter == &SEHHandler)
return REAL(SetUnhandledExceptionFilter)(ExceptionFilter);
// We record the user provided exception handler to be called for all the
// exceptions unhandled by asan.
Swap(ExceptionFilter, user_seh_handler);
return ExceptionFilter;
}
INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
CHECK(REAL(RtlRaiseException));
// This is a noreturn function, unless it's one of the exceptions raised to
// communicate with the debugger, such as the one from OutputDebugString.
if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
__asan_handle_no_return();
REAL(RtlRaiseException)(ExceptionRecord);
}
INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
CHECK(REAL(RaiseException));
__asan_handle_no_return();
REAL(RaiseException)(a, b, c, d);
}
#ifdef _WIN64
INTERCEPTOR_WINAPI(EXCEPTION_DISPOSITION, __C_specific_handler,
_EXCEPTION_RECORD *a, void *b, _CONTEXT *c,
_DISPATCHER_CONTEXT *d) {
CHECK(REAL(__C_specific_handler));
__asan_handle_no_return();
return REAL(__C_specific_handler)(a, b, c, d);
}
#else
INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
CHECK(REAL(_except_handler3));
__asan_handle_no_return();
return REAL(_except_handler3)(a, b, c, d);
}
#if ASAN_DYNAMIC
// This handler is named differently in -MT and -MD CRTs.
#define _except_handler4 _except_handler4_common
#endif
INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
CHECK(REAL(_except_handler4));
__asan_handle_no_return();
return REAL(_except_handler4)(a, b, c, d);
}
#endif
static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
AsanThread *t = (AsanThread *)arg;
SetCurrentThread(t);
return t->ThreadStart(GetTid(), /* signal_thread_is_registered */ nullptr);
}
INTERCEPTOR_WINAPI(HANDLE, CreateThread, LPSECURITY_ATTRIBUTES security,
SIZE_T stack_size, LPTHREAD_START_ROUTINE start_routine,
void *arg, DWORD thr_flags, DWORD *tid) {
// Strict init-order checking is thread-hostile.
if (flags()->strict_init_order)
StopInitOrderChecking();
GET_STACK_TRACE_THREAD;
// FIXME: The CreateThread interceptor is not the same as a pthread_create
// one. This is a bandaid fix for PR22025.
bool detached = false; // FIXME: how can we determine it on Windows?
u32 current_tid = GetCurrentTidOrInvalid();
AsanThread *t =
AsanThread::Create(start_routine, arg, current_tid, &stack, detached);
return REAL(CreateThread)(security, stack_size, asan_thread_start, t,
thr_flags, tid);
}
// }}}
namespace __asan {
void InitializePlatformInterceptors() {
// The interceptors were not designed to be removable, so we have to keep this
// module alive for the life of the process.
HMODULE pinned;
CHECK(GetModuleHandleExW(
GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
(LPCWSTR)&InitializePlatformInterceptors, &pinned));
ASAN_INTERCEPT_FUNC(CreateThread);
ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
#ifdef _WIN64
ASAN_INTERCEPT_FUNC(__C_specific_handler);
#else
ASAN_INTERCEPT_FUNC(_except_handler3);
ASAN_INTERCEPT_FUNC(_except_handler4);
#endif
// Try to intercept kernel32!RaiseException, and if that fails, intercept
// ntdll!RtlRaiseException instead.
if (!::__interception::OverrideFunction("RaiseException",
(uptr)WRAP(RaiseException),
(uptr *)&REAL(RaiseException))) {
CHECK(::__interception::OverrideFunction("RtlRaiseException",
(uptr)WRAP(RtlRaiseException),
(uptr *)&REAL(RtlRaiseException)));
}
}
void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
UNIMPLEMENTED();
}
// ---------------------- TSD ---------------- {{{
static bool tsd_key_inited = false;
static __declspec(thread) void *fake_tsd = 0;
// https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb
// "[This structure may be altered in future versions of Windows. Applications
// should use the alternate functions listed in this topic.]"
typedef struct _TEB {
PVOID Reserved1[12];
// PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1.
PVOID ProcessEnvironmentBlock;
PVOID Reserved2[399];
BYTE Reserved3[1952];
PVOID TlsSlots[64];
BYTE Reserved4[8];
PVOID Reserved5[26];
PVOID ReservedForOle;
PVOID Reserved6[4];
PVOID TlsExpansionSlots;
} TEB, *PTEB;
constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11;
BOOL IsTlsInitialized() {
PTEB teb = (PTEB)NtCurrentTeb();
return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] !=
nullptr;
}
void AsanTSDInit(void (*destructor)(void *tsd)) {
// FIXME: we're ignoring the destructor for now.
tsd_key_inited = true;
}
void *AsanTSDGet() {
CHECK(tsd_key_inited);
return IsTlsInitialized() ? fake_tsd : nullptr;
}
void AsanTSDSet(void *tsd) {
CHECK(tsd_key_inited);
fake_tsd = tsd;
}
void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); }
// }}}
// ---------------------- Various stuff ---------------- {{{
void *AsanDoesNotSupportStaticLinkage() {
#if defined(_DEBUG)
#error Please build the runtime with a non-debug CRT: /MD or /MT
#endif
return 0;
}
uptr FindDynamicShadowStart() {
uptr granularity = GetMmapGranularity();
uptr alignment = 8 * granularity;
uptr left_padding = granularity;
uptr space_size = kHighShadowEnd + left_padding;
uptr shadow_start = FindAvailableMemoryRange(space_size, alignment,
granularity, nullptr, nullptr);
CHECK_NE((uptr)0, shadow_start);
CHECK(IsAligned(shadow_start, alignment));
return shadow_start;
}
void AsanCheckDynamicRTPrereqs() {}
void AsanCheckIncompatibleRT() {}
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
UNIMPLEMENTED();
}
void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); }
#if SANITIZER_WINDOWS64
// Exception handler for dealing with shadow memory.
static LONG CALLBACK
ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
uptr page_size = GetPageSizeCached();
// Only handle access violations.
if (exception_pointers->ExceptionRecord->ExceptionCode !=
EXCEPTION_ACCESS_VIOLATION ||
exception_pointers->ExceptionRecord->NumberParameters < 2) {
__asan_handle_no_return();
return EXCEPTION_CONTINUE_SEARCH;
}
// Only handle access violations that land within the shadow memory.
uptr addr =
(uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
// Check valid shadow range.
if (!AddrIsInShadow(addr)) {
__asan_handle_no_return();
return EXCEPTION_CONTINUE_SEARCH;
}
// This is an access violation while trying to read from the shadow. Commit
// the relevant page and let execution continue.
// Determine the address of the page that is being accessed.
uptr page = RoundDownTo(addr, page_size);
// Commit the page.
uptr result =
(uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
if (result != page)
return EXCEPTION_CONTINUE_SEARCH;
// The page mapping succeeded, so continue execution as usual.
return EXCEPTION_CONTINUE_EXECUTION;
}
#endif
void InitializePlatformExceptionHandlers() {
#if SANITIZER_WINDOWS64
// On Win64, we map memory on demand with access violation handler.
// Install our exception handler.
CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
#endif
}
bool IsSystemHeapAddress(uptr addr) {
return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE;
}
// We want to install our own exception handler (EH) to print helpful reports
// on access violations and whatnot. Unfortunately, the CRT initializers assume
// they are run before any user code and drop any previously-installed EHs on
// the floor, so we can't install our handler inside __asan_init.
// (See crt0dat.c in the CRT sources for the details)
//
// Things get even more complicated with the dynamic runtime, as it finishes its
// initialization before the .exe module CRT begins to initialize.
//
// For the static runtime (-MT), it's enough to put a callback to
// __asan_set_seh_filter in the last section for C initializers.
//
// For the dynamic runtime (-MD), we want link the same
// asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
// will be called for each instrumented module. This ensures that at least one
// __asan_set_seh_filter call happens after the .exe module CRT is initialized.
extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() {
// We should only store the previous handler if it's not our own handler in
// order to avoid loops in the EH chain.
auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
if (prev_seh_handler != &SEHHandler)
default_seh_handler = prev_seh_handler;
return 0;
}
bool HandleDlopenInit() {
// Not supported on this platform.
static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN,
"Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false");
return false;
}
#if !ASAN_DYNAMIC
// The CRT runs initializers in this order:
// - C initializers, from XIA to XIZ
// - C++ initializers, from XCA to XCZ
// Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
// near the end of C initialization. Starting in 2015, it was moved to the
// beginning of C++ initialization. We set our priority to XCAB to run
// immediately after the CRT runs. This way, our exception filter is called
// first and we can delegate to their filter if appropriate.
#pragma section(".CRT$XCAB", long, read)
__declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
__asan_set_seh_filter;
// Piggyback on the TLS initialization callback directory to initialize asan as
// early as possible. Initializers in .CRT$XL* are called directly by ntdll,
// which run before the CRT. Users also add code to .CRT$XLC, so it's important
// to run our initializers first.
static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
if (reason == DLL_PROCESS_ATTACH)
__asan_init();
}
#pragma section(".CRT$XLAB", long, read)
__declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)(
void *, unsigned long, void *) = asan_thread_init;
#endif
static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) {
if (reason == DLL_THREAD_DETACH) {
// Unpoison the thread's stack because the memory may be re-used.
NT_TIB *tib = (NT_TIB *)NtCurrentTeb();
uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit;
__asan_unpoison_memory_region(tib->StackLimit, stackSize);
}
}
#pragma section(".CRT$XLY", long, read)
__declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)(
void *, unsigned long, void *) = asan_thread_exit;
WIN_FORCE_LINK(__asan_dso_reg_hook)
// }}}
} // namespace __asan
#endif // SANITIZER_WINDOWS