libsanitizer/asan/asan_win.cpp

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