1//===-- asan_win.cpp ------------------------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file is a part of AddressSanitizer, an address sanity checker. 10// 11// Windows-specific details. 12//===----------------------------------------------------------------------===// 13 14#include "sanitizer_common/sanitizer_platform.h" 15#if SANITIZER_WINDOWS 16#define WIN32_LEAN_AND_MEAN 17#include <windows.h> 18 19#include <stdlib.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 53long __asan_unhandled_exception_filter(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 134static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) { 135 AsanThread *t = (AsanThread *)arg; 136 SetCurrentThread(t); 137 return t->ThreadStart(GetTid()); 138} 139 140INTERCEPTOR_WINAPI(HANDLE, CreateThread, LPSECURITY_ATTRIBUTES security, 141 SIZE_T stack_size, LPTHREAD_START_ROUTINE start_routine, 142 void *arg, DWORD thr_flags, DWORD *tid) { 143 // Strict init-order checking is thread-hostile. 144 if (flags()->strict_init_order) 145 StopInitOrderChecking(); 146 GET_STACK_TRACE_THREAD; 147 // FIXME: The CreateThread interceptor is not the same as a pthread_create 148 // one. This is a bandaid fix for PR22025. 149 bool detached = false; // FIXME: how can we determine it on Windows? 150 u32 current_tid = GetCurrentTidOrInvalid(); 151 AsanThread *t = 152 AsanThread::Create(start_routine, arg, current_tid, &stack, detached); 153 return REAL(CreateThread)(security, stack_size, asan_thread_start, t, 154 thr_flags, tid); 155} 156 157// }}} 158 159namespace __asan { 160 161void InitializePlatformInterceptors() { 162 // The interceptors were not designed to be removable, so we have to keep this 163 // module alive for the life of the process. 164 HMODULE pinned; 165 CHECK(GetModuleHandleExW( 166 GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN, 167 (LPCWSTR)&InitializePlatformInterceptors, &pinned)); 168 169 ASAN_INTERCEPT_FUNC(CreateThread); 170 ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter); 171 172#ifdef _WIN64 173 ASAN_INTERCEPT_FUNC(__C_specific_handler); 174#else 175 ASAN_INTERCEPT_FUNC(_except_handler3); 176 ASAN_INTERCEPT_FUNC(_except_handler4); 177#endif 178 179 // Try to intercept kernel32!RaiseException, and if that fails, intercept 180 // ntdll!RtlRaiseException instead. 181 if (!::__interception::OverrideFunction("RaiseException", 182 (uptr)WRAP(RaiseException), 183 (uptr *)&REAL(RaiseException))) { 184 CHECK(::__interception::OverrideFunction("RtlRaiseException", 185 (uptr)WRAP(RtlRaiseException), 186 (uptr *)&REAL(RtlRaiseException))); 187 } 188} 189 190void AsanApplyToGlobals(globals_op_fptr op, const void *needle) { 191 UNIMPLEMENTED(); 192} 193 194void FlushUnneededASanShadowMemory(uptr p, uptr size) { 195 // Since asan's mapping is compacting, the shadow chunk may be 196 // not page-aligned, so we only flush the page-aligned portion. 197 ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size)); 198} 199 200// ---------------------- TSD ---------------- {{{ 201static bool tsd_key_inited = false; 202 203static __declspec(thread) void *fake_tsd = 0; 204 205// https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb 206// "[This structure may be altered in future versions of Windows. Applications 207// should use the alternate functions listed in this topic.]" 208typedef struct _TEB { 209 PVOID Reserved1[12]; 210 // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1. 211 PVOID ProcessEnvironmentBlock; 212 PVOID Reserved2[399]; 213 BYTE Reserved3[1952]; 214 PVOID TlsSlots[64]; 215 BYTE Reserved4[8]; 216 PVOID Reserved5[26]; 217 PVOID ReservedForOle; 218 PVOID Reserved6[4]; 219 PVOID TlsExpansionSlots; 220} TEB, *PTEB; 221 222constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11; 223BOOL IsTlsInitialized() { 224 PTEB teb = (PTEB)NtCurrentTeb(); 225 return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] != 226 nullptr; 227} 228 229void AsanTSDInit(void (*destructor)(void *tsd)) { 230 // FIXME: we're ignoring the destructor for now. 231 tsd_key_inited = true; 232} 233 234void *AsanTSDGet() { 235 CHECK(tsd_key_inited); 236 return IsTlsInitialized() ? fake_tsd : nullptr; 237} 238 239void AsanTSDSet(void *tsd) { 240 CHECK(tsd_key_inited); 241 fake_tsd = tsd; 242} 243 244void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); } 245// }}} 246 247// ---------------------- Various stuff ---------------- {{{ 248void *AsanDoesNotSupportStaticLinkage() { 249#if defined(_DEBUG) 250#error Please build the runtime with a non-debug CRT: /MD or /MT 251#endif 252 return 0; 253} 254 255uptr FindDynamicShadowStart() { 256 return MapDynamicShadow(MemToShadowSize(kHighMemEnd), SHADOW_SCALE, 257 /*min_shadow_base_alignment*/ 0, kHighMemEnd); 258} 259 260void AsanCheckDynamicRTPrereqs() {} 261 262void AsanCheckIncompatibleRT() {} 263 264void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 265 UNIMPLEMENTED(); 266} 267 268void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); } 269 270bool PlatformUnpoisonStacks() { return false; } 271 272#if SANITIZER_WINDOWS64 273// Exception handler for dealing with shadow memory. 274static LONG CALLBACK 275ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) { 276 uptr page_size = GetPageSizeCached(); 277 // Only handle access violations. 278 if (exception_pointers->ExceptionRecord->ExceptionCode != 279 EXCEPTION_ACCESS_VIOLATION || 280 exception_pointers->ExceptionRecord->NumberParameters < 2) { 281 __asan_handle_no_return(); 282 return EXCEPTION_CONTINUE_SEARCH; 283 } 284 285 // Only handle access violations that land within the shadow memory. 286 uptr addr = 287 (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]); 288 289 // Check valid shadow range. 290 if (!AddrIsInShadow(addr)) { 291 __asan_handle_no_return(); 292 return EXCEPTION_CONTINUE_SEARCH; 293 } 294 295 // This is an access violation while trying to read from the shadow. Commit 296 // the relevant page and let execution continue. 297 298 // Determine the address of the page that is being accessed. 299 uptr page = RoundDownTo(addr, page_size); 300 301 // Commit the page. 302 uptr result = 303 (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE); 304 if (result != page) 305 return EXCEPTION_CONTINUE_SEARCH; 306 307 // The page mapping succeeded, so continue execution as usual. 308 return EXCEPTION_CONTINUE_EXECUTION; 309} 310 311#endif 312 313void InitializePlatformExceptionHandlers() { 314#if SANITIZER_WINDOWS64 315 // On Win64, we map memory on demand with access violation handler. 316 // Install our exception handler. 317 CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler)); 318#endif 319} 320 321bool IsSystemHeapAddress(uptr addr) { 322 return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE; 323} 324 325// We want to install our own exception handler (EH) to print helpful reports 326// on access violations and whatnot. Unfortunately, the CRT initializers assume 327// they are run before any user code and drop any previously-installed EHs on 328// the floor, so we can't install our handler inside __asan_init. 329// (See crt0dat.c in the CRT sources for the details) 330// 331// Things get even more complicated with the dynamic runtime, as it finishes its 332// initialization before the .exe module CRT begins to initialize. 333// 334// For the static runtime (-MT), it's enough to put a callback to 335// __asan_set_seh_filter in the last section for C initializers. 336// 337// For the dynamic runtime (-MD), we want link the same 338// asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter 339// will be called for each instrumented module. This ensures that at least one 340// __asan_set_seh_filter call happens after the .exe module CRT is initialized. 341extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() { 342 // We should only store the previous handler if it's not our own handler in 343 // order to avoid loops in the EH chain. 344 auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler); 345 if (prev_seh_handler != &SEHHandler) 346 default_seh_handler = prev_seh_handler; 347 return 0; 348} 349 350bool HandleDlopenInit() { 351 // Not supported on this platform. 352 static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN, 353 "Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false"); 354 return false; 355} 356 357#if !ASAN_DYNAMIC 358// The CRT runs initializers in this order: 359// - C initializers, from XIA to XIZ 360// - C++ initializers, from XCA to XCZ 361// Prior to 2015, the CRT set the unhandled exception filter at priority XIY, 362// near the end of C initialization. Starting in 2015, it was moved to the 363// beginning of C++ initialization. We set our priority to XCAB to run 364// immediately after the CRT runs. This way, our exception filter is called 365// first and we can delegate to their filter if appropriate. 366#pragma section(".CRT$XCAB", long, read) 367__declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() = 368 __asan_set_seh_filter; 369 370// Piggyback on the TLS initialization callback directory to initialize asan as 371// early as possible. Initializers in .CRT$XL* are called directly by ntdll, 372// which run before the CRT. Users also add code to .CRT$XLC, so it's important 373// to run our initializers first. 374static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) { 375 if (reason == DLL_PROCESS_ATTACH) 376 __asan_init(); 377} 378 379#pragma section(".CRT$XLAB", long, read) 380__declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)( 381 void *, unsigned long, void *) = asan_thread_init; 382#endif 383 384static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) { 385 if (reason == DLL_THREAD_DETACH) { 386 // Unpoison the thread's stack because the memory may be re-used. 387 NT_TIB *tib = (NT_TIB *)NtCurrentTeb(); 388 uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit; 389 __asan_unpoison_memory_region(tib->StackLimit, stackSize); 390 } 391} 392 393#pragma section(".CRT$XLY", long, read) 394__declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)( 395 void *, unsigned long, void *) = asan_thread_exit; 396 397WIN_FORCE_LINK(__asan_dso_reg_hook) 398 399// }}} 400} // namespace __asan 401 402#endif // SANITIZER_WINDOWS 403