libsanitizer/asan/asan_win.cpp

   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
  32 using namespace __asan;
  33
  34 extern "C" {
  35 SANITIZER_INTERFACE_ATTRIBUTE
  36 int __asan_should_detect_stack_use_after_return() {
  37   __asan_init();
  38   return __asan_option_detect_stack_use_after_return;
  39 }
  40
  41 SANITIZER_INTERFACE_ATTRIBUTE
  42 uptr __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 ---------------- {{{
  49 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
  50 static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler;
  51
  52 extern "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.
  67 static 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
  79 INTERCEPTOR_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
  90 INTERCEPTOR_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
  99 INTERCEPTOR_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
 107 INTERCEPTOR_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
 117 INTERCEPTOR(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
 127 INTERCEPTOR(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
 134 static 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
 140 INTERCEPTOR_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
 159 namespace __asan {
 160
 161 void 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
 190 void InstallAtExitCheckLeaks() {}
 191
 192 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 193   UNIMPLEMENTED();
 194 }
 195
 196 void FlushUnneededASanShadowMemory(uptr p, uptr size) {
 197   // Since asan's mapping is compacting, the shadow chunk may be
 198   // not page-aligned, so we only flush the page-aligned portion.
 199   ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
 200 }
 201
 202 // ---------------------- TSD ---------------- {{{
 203 static bool tsd_key_inited = false;
 204
 205 static __declspec(thread) void *fake_tsd = 0;
 206
 207 // https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb
 208 // "[This structure may be altered in future versions of Windows. Applications
 209 // should use the alternate functions listed in this topic.]"
 210 typedef struct _TEB {
 211   PVOID Reserved1[12];
 212   // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1.
 213   PVOID ProcessEnvironmentBlock;
 214   PVOID Reserved2[399];
 215   BYTE Reserved3[1952];
 216   PVOID TlsSlots[64];
 217   BYTE Reserved4[8];
 218   PVOID Reserved5[26];
 219   PVOID ReservedForOle;
 220   PVOID Reserved6[4];
 221   PVOID TlsExpansionSlots;
 222 } TEB, *PTEB;
 223
 224 constexpr size_t TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11;
 225 BOOL IsTlsInitialized() {
 226   PTEB teb = (PTEB)NtCurrentTeb();
 227   return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] !=
 228          nullptr;
 229 }
 230
 231 void AsanTSDInit(void (*destructor)(void *tsd)) {
 232   // FIXME: we're ignoring the destructor for now.
 233   tsd_key_inited = true;
 234 }
 235
 236 void *AsanTSDGet() {
 237   CHECK(tsd_key_inited);
 238   return IsTlsInitialized() ? fake_tsd : nullptr;
 239 }
 240
 241 void AsanTSDSet(void *tsd) {
 242   CHECK(tsd_key_inited);
 243   fake_tsd = tsd;
 244 }
 245
 246 void PlatformTSDDtor(void *tsd) { AsanThread::TSDDtor(tsd); }
 247 // }}}
 248
 249 // ---------------------- Various stuff ---------------- {{{
 250 void *AsanDoesNotSupportStaticLinkage() {
 251 #if defined(_DEBUG)
 252 #error Please build the runtime with a non-debug CRT: /MD or /MT
 253 #endif
 254   return 0;
 255 }
 256
 257 uptr FindDynamicShadowStart() {
 258   return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
 259                           /*min_shadow_base_alignment*/ 0, kHighMemEnd);
 260 }
 261
 262 void AsanCheckDynamicRTPrereqs() {}
 263
 264 void AsanCheckIncompatibleRT() {}
 265
 266 void AsanOnDeadlySignal(int, void *siginfo, void *context) { UNIMPLEMENTED(); }
 267
 268 bool PlatformUnpoisonStacks() { return false; }
 269
 270 #if SANITIZER_WINDOWS64
 271 // Exception handler for dealing with shadow memory.
 272 static LONG CALLBACK
 273 ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
 274   uptr page_size = GetPageSizeCached();
 275   // Only handle access violations.
 276   if (exception_pointers->ExceptionRecord->ExceptionCode !=
 277           EXCEPTION_ACCESS_VIOLATION ||
 278       exception_pointers->ExceptionRecord->NumberParameters < 2) {
 279     __asan_handle_no_return();
 280     return EXCEPTION_CONTINUE_SEARCH;
 281   }
 282
 283   // Only handle access violations that land within the shadow memory.
 284   uptr addr =
 285       (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
 286
 287   // Check valid shadow range.
 288   if (!AddrIsInShadow(addr)) {
 289     __asan_handle_no_return();
 290     return EXCEPTION_CONTINUE_SEARCH;
 291   }
 292
 293   // This is an access violation while trying to read from the shadow. Commit
 294   // the relevant page and let execution continue.
 295
 296   // Determine the address of the page that is being accessed.
 297   uptr page = RoundDownTo(addr, page_size);
 298
 299   // Commit the page.
 300   uptr result =
 301       (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
 302   if (result != page)
 303     return EXCEPTION_CONTINUE_SEARCH;
 304
 305   // The page mapping succeeded, so continue execution as usual.
 306   return EXCEPTION_CONTINUE_EXECUTION;
 307 }
 308
 309 #endif
 310
 311 void InitializePlatformExceptionHandlers() {
 312 #if SANITIZER_WINDOWS64
 313   // On Win64, we map memory on demand with access violation handler.
 314   // Install our exception handler.
 315   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 316 #endif
 317 }
 318
 319 bool IsSystemHeapAddress(uptr addr) {
 320   return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE;
 321 }
 322
 323 // We want to install our own exception handler (EH) to print helpful reports
 324 // on access violations and whatnot.  Unfortunately, the CRT initializers assume
 325 // they are run before any user code and drop any previously-installed EHs on
 326 // the floor, so we can't install our handler inside __asan_init.
 327 // (See crt0dat.c in the CRT sources for the details)
 328 //
 329 // Things get even more complicated with the dynamic runtime, as it finishes its
 330 // initialization before the .exe module CRT begins to initialize.
 331 //
 332 // For the static runtime (-MT), it's enough to put a callback to
 333 // __asan_set_seh_filter in the last section for C initializers.
 334 //
 335 // For the dynamic runtime (-MD), we want link the same
 336 // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
 337 // will be called for each instrumented module.  This ensures that at least one
 338 // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
 339 extern "C" SANITIZER_INTERFACE_ATTRIBUTE int __asan_set_seh_filter() {
 340   // We should only store the previous handler if it's not our own handler in
 341   // order to avoid loops in the EH chain.
 342   auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
 343   if (prev_seh_handler != &SEHHandler)
 344     default_seh_handler = prev_seh_handler;
 345   return 0;
 346 }
 347
 348 bool HandleDlopenInit() {
 349   // Not supported on this platform.
 350   static_assert(!SANITIZER_SUPPORTS_INIT_FOR_DLOPEN,
 351                 "Expected SANITIZER_SUPPORTS_INIT_FOR_DLOPEN to be false");
 352   return false;
 353 }
 354
 355 #if !ASAN_DYNAMIC
 356 // The CRT runs initializers in this order:
 357 // - C initializers, from XIA to XIZ
 358 // - C++ initializers, from XCA to XCZ
 359 // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
 360 // near the end of C initialization. Starting in 2015, it was moved to the
 361 // beginning of C++ initialization. We set our priority to XCAB to run
 362 // immediately after the CRT runs. This way, our exception filter is called
 363 // first and we can delegate to their filter if appropriate.
 364 #pragma section(".CRT$XCAB", long, read)
 365 __declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
 366     __asan_set_seh_filter;
 367
 368 // Piggyback on the TLS initialization callback directory to initialize asan as
 369 // early as possible. Initializers in .CRT$XL* are called directly by ntdll,
 370 // which run before the CRT. Users also add code to .CRT$XLC, so it's important
 371 // to run our initializers first.
 372 static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
 373   if (reason == DLL_PROCESS_ATTACH)
 374     __asan_init();
 375 }
 376
 377 #pragma section(".CRT$XLAB", long, read)
 378 __declspec(allocate(".CRT$XLAB")) void(NTAPI *__asan_tls_init)(
 379     void *, unsigned long, void *) = asan_thread_init;
 380 #endif
 381
 382 static void NTAPI asan_thread_exit(void *module, DWORD reason, void *reserved) {
 383   if (reason == DLL_THREAD_DETACH) {
 384     // Unpoison the thread's stack because the memory may be re-used.
 385     NT_TIB *tib = (NT_TIB *)NtCurrentTeb();
 386     uptr stackSize = (uptr)tib->StackBase - (uptr)tib->StackLimit;
 387     __asan_unpoison_memory_region(tib->StackLimit, stackSize);
 388   }
 389 }
 390
 391 #pragma section(".CRT$XLY", long, read)
 392 __declspec(allocate(".CRT$XLY")) void(NTAPI *__asan_tls_exit)(
 393     void *, unsigned long, void *) = asan_thread_exit;
 394
 395 WIN_FORCE_LINK(__asan_dso_reg_hook)
 396
 397 // }}}
 398 }  // namespace __asan
 399
 400 #endif  // SANITIZER_WINDOWS