1//===-- asan_win.cpp 2//------------------------------------------------------===//> 3// 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5// See https://llvm.org/LICENSE.txt for license information. 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of AddressSanitizer, an address sanity checker. 11// 12// Windows-specific details. 13//===----------------------------------------------------------------------===// 14 15#include "sanitizer_common/sanitizer_platform.h" 16#if SANITIZER_WINDOWS 17# define WIN32_LEAN_AND_MEAN 18# include <stdlib.h> 19# include <windows.h> 20 21# include "asan_interceptors.h" 22# include "asan_internal.h" 23# include "asan_mapping.h" 24# include "asan_report.h" 25# include "asan_stack.h" 26# include "asan_thread.h" 27# include "sanitizer_common/sanitizer_libc.h" 28# include "sanitizer_common/sanitizer_mutex.h" 29# include "sanitizer_common/sanitizer_win.h" 30# include "sanitizer_common/sanitizer_win_defs.h" 31 32using namespace __asan; 33 34extern "C" { 35SANITIZER_INTERFACE_ATTRIBUTE 36int __asan_should_detect_stack_use_after_return() { 37 __asan_init(); 38 return __asan_option_detect_stack_use_after_return; 39} 40 41SANITIZER_INTERFACE_ATTRIBUTE 42uptr __asan_get_shadow_memory_dynamic_address() { 43 __asan_init(); 44 return __asan_shadow_memory_dynamic_address; 45} 46} // extern "C" 47 48// ---------------------- Windows-specific interceptors ---------------- {{{ 49static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler; 50static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler; 51 52extern "C" SANITIZER_INTERFACE_ATTRIBUTE long __asan_unhandled_exception_filter( 53 EXCEPTION_POINTERS *info) { 54 EXCEPTION_RECORD *exception_record = info->ExceptionRecord; 55 CONTEXT *context = info->ContextRecord; 56 57 // FIXME: Handle EXCEPTION_STACK_OVERFLOW here. 58 59 SignalContext sig(exception_record, context); 60 ReportDeadlySignal(sig); 61 UNREACHABLE("returned from reporting deadly signal"); 62} 63 64// Wrapper SEH Handler. If the exception should be handled by asan, we call 65// __asan_unhandled_exception_filter, otherwise, we execute the user provided 66// exception handler or the default. 67static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) { 68 DWORD exception_code = info->ExceptionRecord->ExceptionCode; 69 if (__sanitizer::IsHandledDeadlyException(exception_code)) 70 return __asan_unhandled_exception_filter(info); 71 if (user_seh_handler) 72 return user_seh_handler(info); 73 // Bubble out to the default exception filter. 74 if (default_seh_handler) 75 return default_seh_handler(info); 76 return EXCEPTION_CONTINUE_SEARCH; 77} 78 79INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER, SetUnhandledExceptionFilter, 80 LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter) { 81 CHECK(REAL(SetUnhandledExceptionFilter)); 82 if (ExceptionFilter == &SEHHandler) 83 return REAL(SetUnhandledExceptionFilter)(ExceptionFilter); 84 // We record the user provided exception handler to be called for all the 85 // exceptions unhandled by asan. 86 Swap(ExceptionFilter, user_seh_handler); 87 return ExceptionFilter; 88} 89 90INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) { 91 CHECK(REAL(RtlRaiseException)); 92 // This is a noreturn function, unless it's one of the exceptions raised to 93 // communicate with the debugger, such as the one from OutputDebugString. 94 if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C) 95 __asan_handle_no_return(); 96 REAL(RtlRaiseException)(ExceptionRecord); 97} 98 99INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) { 100 CHECK(REAL(RaiseException)); 101 __asan_handle_no_return(); 102 REAL(RaiseException)(a, b, c, d); 103} 104 105#ifdef _WIN64 106 107INTERCEPTOR_WINAPI(EXCEPTION_DISPOSITION, __C_specific_handler, 108 _EXCEPTION_RECORD *a, void *b, _CONTEXT *c, 109 _DISPATCHER_CONTEXT *d) { 110 CHECK(REAL(__C_specific_handler)); 111 __asan_handle_no_return(); 112 return REAL(__C_specific_handler)(a, b, c, d); 113} 114 115#else 116 117INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) { 118 CHECK(REAL(_except_handler3)); 119 __asan_handle_no_return(); 120 return REAL(_except_handler3)(a, b, c, d); 121} 122 123#if ASAN_DYNAMIC 124// This handler is named differently in -MT and -MD CRTs. 125#define _except_handler4 _except_handler4_common 126#endif 127INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) { 128 CHECK(REAL(_except_handler4)); 129 __asan_handle_no_return(); 130 return REAL(_except_handler4)(a, b, c, d); 131} 132#endif 133 134struct ThreadStartParams { 135 thread_callback_t start_routine; 136 void *arg; 137}; 138 139static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) { 140 AsanThread *t = (AsanThread *)arg; 141 SetCurrentThread(t); 142 t->ThreadStart(GetTid()); 143 144 ThreadStartParams params; 145 t->GetStartData(params); 146 147 auto res = (*params.start_routine)(params.arg); 148 t->Destroy(); // POSIX calls this from TSD destructor. 149 return res; 150} 151 152INTERCEPTOR_WINAPI(HANDLE, CreateThread, LPSECURITY_ATTRIBUTES security, 153 SIZE_T stack_size, LPTHREAD_START_ROUTINE start_routine, 154 void *arg, DWORD thr_flags, DWORD *tid) { 155 // Strict init-order checking is thread-hostile. 156 if (flags()->strict_init_order) 157 StopInitOrderChecking(); 158 GET_STACK_TRACE_THREAD; 159 // FIXME: The CreateThread interceptor is not the same as a pthread_create 160 // one. This is a bandaid fix for PR22025. 161 bool detached = false; // FIXME: how can we determine it on Windows? 162 u32 current_tid = GetCurrentTidOrInvalid(); 163 ThreadStartParams params = {start_routine, arg}; 164 AsanThread *t = AsanThread::Create(params, current_tid, &stack, detached); 165 return REAL(CreateThread)(security, stack_size, asan_thread_start, t, 166 thr_flags, tid); 167} 168 169// }}} 170 171namespace __asan { 172 173void InitializePlatformInterceptors() { 174 __interception::SetErrorReportCallback(Report); 175 176 // The interceptors were not designed to be removable, so we have to keep this 177 // module alive for the life of the process. 178 HMODULE pinned; 179 CHECK(GetModuleHandleExW( 180 GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN, 181 (LPCWSTR)&InitializePlatformInterceptors, &pinned)); 182 183 ASAN_INTERCEPT_FUNC(CreateThread); 184 ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter); 185 186#ifdef _WIN64 187 ASAN_INTERCEPT_FUNC(__C_specific_handler); 188#else 189 ASAN_INTERCEPT_FUNC(_except_handler3); 190 ASAN_INTERCEPT_FUNC(_except_handler4); 191#endif 192 193 // Try to intercept kernel32!RaiseException, and if that fails, intercept 194 // ntdll!RtlRaiseException instead. 195 if (!::__interception::OverrideFunction("RaiseException", 196 (uptr)WRAP(RaiseException), 197 (uptr *)&REAL(RaiseException))) { 198 CHECK(::__interception::OverrideFunction("RtlRaiseException", 199 (uptr)WRAP(RtlRaiseException), 200 (uptr *)&REAL(RtlRaiseException))); 201 } 202} 203 204void InstallAtExitCheckLeaks() {} 205 206void InstallAtForkHandler() {} 207 208void AsanApplyToGlobals(globals_op_fptr op, const void *needle) { 209 UNIMPLEMENTED(); 210} 211 212void FlushUnneededASanShadowMemory(uptr p, uptr size) { 213 // Only asan on 64-bit Windows supports committing shadow memory on demand. 214#if SANITIZER_WINDOWS64 215 // Since asan's mapping is compacting, the shadow chunk may be 216 // not page-aligned, so we only flush the page-aligned portion. 217 ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size)); 218#endif 219} 220 221// ---------------------- TSD ---------------- {{{ 222static bool tsd_key_inited = false; 223 224static __declspec(thread) void *fake_tsd = 0; 225 226// https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb 227// "[This structure may be altered in future versions of Windows. Applications 228// should use the alternate functions listed in this topic.]" 229typedef struct _TEB { 230 PVOID Reserved1[12]; 231 // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1. 232 PVOID ProcessEnvironmentBlock; 233 PVOID Reserved2[399]; 234 BYTE Reserved3[1952]; 235 PVOID TlsSlots[64]; 236 BYTE Reserved4[8]; 237 PVOID Reserved5[26]; 238 PVOID ReservedForOle; 239 PVOID Reserved6[4]; 240 PVOID TlsExpansionSlots; 241} TEB, *PTEB; 242 243constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11; 244BOOL IsTlsInitialized() { 245 PTEB teb = (PTEB)NtCurrentTeb(); 246 return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] != 247 nullptr; 248} 249 250void AsanTSDInit(void (*destructor)(void *tsd)) { 251 // FIXME: we're ignoring the destructor for now. 252 tsd_key_inited = true; 253} 254 255void *AsanTSDGet() { 256 CHECK(tsd_key_inited); 257 return IsTlsInitialized() ? fake_tsd : nullptr; 258} 259 260void AsanTSDSet(void *tsd) { 261 CHECK(tsd_key_inited); 262 fake_tsd = tsd; 263} 264 265void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); } 266// }}} 267 268// ---------------------- Various stuff ---------------- {{{ 269void *AsanDoesNotSupportStaticLinkage() { return 0; } 270 271uptr FindDynamicShadowStart() { 272 return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE, 273 /*min_shadow_base_alignment*/ 0, kHighMemEnd); 274} 275 276void AsanCheckDynamicRTPrereqs() {} 277 278void AsanCheckIncompatibleRT() {} 279 280void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); } 281 282bool PlatformUnpoisonStacks() { return false; } 283 284#if SANITIZER_WINDOWS64 285// Exception handler for dealing with shadow memory. 286static LONG CALLBACK 287ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) { 288 uptr page_size = GetPageSizeCached(); 289 // Only handle access violations. 290 if (exception_pointers->ExceptionRecord->ExceptionCode != 291 EXCEPTION_ACCESS_VIOLATION || 292 exception_pointers->ExceptionRecord->NumberParameters < 2) { 293 __asan_handle_no_return(); 294 return EXCEPTION_CONTINUE_SEARCH; 295 } 296 297 // Only handle access violations that land within the shadow memory. 298 uptr addr = 299 (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]); 300 301 // Check valid shadow range. 302 if (!AddrIsInShadow(addr)) { 303 __asan_handle_no_return(); 304 return EXCEPTION_CONTINUE_SEARCH; 305 } 306 307 // This is an access violation while trying to read from the shadow. Commit 308 // the relevant page and let execution continue. 309 310 // Determine the address of the page that is being accessed. 311 uptr page = RoundDownTo(addr, page_size); 312 313 // Commit the page. 314 uptr result = 315 (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE); 316 if (result != page) 317 return EXCEPTION_CONTINUE_SEARCH; 318 319 // The page mapping succeeded, so continue execution as usual. 320 return EXCEPTION_CONTINUE_EXECUTION; 321} 322 323#endif 324 325void InitializePlatformExceptionHandlers() { 326#if SANITIZER_WINDOWS64 327 // On Win64, we map memory on demand with access violation handler. 328 // Install our exception handler. 329 CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler)); 330#endif 331} 332 333bool IsSystemHeapAddress(uptr addr) { 334 return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE; 335} 336 337// We want to install our own exception handler (EH) to print helpful reports 338// on access violations and whatnot. Unfortunately, the CRT initializers assume 339// they are run before any user code and drop any previously-installed EHs on 340// the floor, so we can't install our handler inside __asan_init. 341// (See crt0dat.c in the CRT sources for the details) 342// 343// Things get even more complicated with the dynamic runtime, as it finishes its 344// initialization before the .exe module CRT begins to initialize. 345// 346// For the static runtime (-MT), it's enough to put a callback to 347// __asan_set_seh_filter in the last section for C initializers. 348// 349// For the dynamic runtime (-MD), we want link the same 350// asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter 351// will be called for each instrumented module. This ensures that at least one 352// __asan_set_seh_filter call happens after the .exe module CRT is initialized. 353extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() { 354 // We should only store the previous handler if it's not our own handler in 355 // order to avoid loops in the EH chain. 356 auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler); 357 if (prev_seh_handler != &SEHHandler) 358 default_seh_handler = prev_seh_handler; 359 return 0; 360} 361 362bool HandleDlopenInit() { 363 // Not supported on this platform. 364 static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN, 365 "Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false"); 366 return false; 367} 368 369#if !ASAN_DYNAMIC 370// The CRT runs initializers in this order: 371// - C initializers, from XIA to XIZ 372// - C++ initializers, from XCA to XCZ 373// Prior to 2015, the CRT set the unhandled exception filter at priority XIY, 374// near the end of C initialization. Starting in 2015, it was moved to the 375// beginning of C++ initialization. We set our priority to XCAB to run 376// immediately after the CRT runs. This way, our exception filter is called 377// first and we can delegate to their filter if appropriate. 378#pragma section(".CRT$XCAB", long, read) 379__declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() = 380 __asan_set_seh_filter; 381 382// Piggyback on the TLS initialization callback directory to initialize asan as 383// early as possible. Initializers in .CRT$XL* are called directly by ntdll, 384// which run before the CRT. Users also add code to .CRT$XLC, so it's important 385// to run our initializers first. 386static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) { 387 if (reason == DLL_PROCESS_ATTACH) 388 __asan_init(); 389} 390 391#pragma section(".CRT$XLAB", long, read) 392__declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)( 393 void *, unsigned long, void *) = asan_thread_init; 394#endif 395 396static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) { 397 if (reason == DLL_THREAD_DETACH) { 398 // Unpoison the thread's stack because the memory may be re-used. 399 NT_TIB *tib = (NT_TIB *)NtCurrentTeb(); 400 uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit; 401 __asan_unpoison_memory_region(tib->StackLimit, stackSize); 402 } 403} 404 405#pragma section(".CRT$XLY", long, read) 406__declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)( 407 void *, unsigned long, void *) = asan_thread_exit; 408 409WIN_FORCE_LINK(__asan_dso_reg_hook) 410 411// }}} 412} // namespace __asan 413 414#endif // SANITIZER_WINDOWS 415