libsanitizer/asan/asan_win.cc

   1 //===-- asan_win.cc -------------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Windows-specific details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_WINDOWS
  15 #define WIN32_LEAN_AND_MEAN
  16 #include <windows.h>
  17
  18 #include <stdlib.h>
  19
  20 #include "asan_interceptors.h"
  21 #include "asan_internal.h"
  22 #include "asan_report.h"
  23 #include "asan_stack.h"
  24 #include "asan_thread.h"
  25 #include "asan_mapping.h"
  26 #include "sanitizer_common/sanitizer_libc.h"
  27 #include "sanitizer_common/sanitizer_mutex.h"
  28 #include "sanitizer_common/sanitizer_win.h"
  29 #include "sanitizer_common/sanitizer_win_defs.h"
  30
  31 using namespace __asan;  // NOLINT
  32
  33 extern "C" {
  34 SANITIZER_INTERFACE_ATTRIBUTE
  35 int __asan_should_detect_stack_use_after_return() {
  36   __asan_init();
  37   return __asan_option_detect_stack_use_after_return;
  38 }
  39
  40 SANITIZER_INTERFACE_ATTRIBUTE
  41 uptr __asan_get_shadow_memory_dynamic_address() {
  42   __asan_init();
  43   return __asan_shadow_memory_dynamic_address;
  44 }
  45 }  // extern "C"
  46
  47 // ---------------------- Windows-specific interceptors ---------------- {{{
  48 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
  49 static LPTOP_LEVEL_EXCEPTION_FILTER user_seh_handler;
  50
  51 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
  52 long __asan_unhandled_exception_filter(EXCEPTION_POINTERS *info) {
  53   EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
  54   CONTEXT *context = info->ContextRecord;
  55
  56   // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
  57
  58   SignalContext sig(exception_record, context);
  59   ReportDeadlySignal(sig);
  60   UNREACHABLE("returned from reporting deadly signal");
  61 }
  62
  63 // Wrapper SEH Handler. If the exception should be handled by asan, we call
  64 // __asan_unhandled_exception_filter, otherwise, we execute the user provided
  65 // exception handler or the default.
  66 static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
  67   DWORD exception_code = info->ExceptionRecord->ExceptionCode;
  68   if (__sanitizer::IsHandledDeadlyException(exception_code))
  69     return __asan_unhandled_exception_filter(info);
  70   if (user_seh_handler)
  71     return user_seh_handler(info);
  72   // Bubble out to the default exception filter.
  73   if (default_seh_handler)
  74     return default_seh_handler(info);
  75   return EXCEPTION_CONTINUE_SEARCH;
  76 }
  77
  78 INTERCEPTOR_WINAPI(LPTOP_LEVEL_EXCEPTION_FILTER, SetUnhandledExceptionFilter,
  79     LPTOP_LEVEL_EXCEPTION_FILTER ExceptionFilter) {
  80   CHECK(REAL(SetUnhandledExceptionFilter));
  81   if (ExceptionFilter == &SEHHandler)
  82     return REAL(SetUnhandledExceptionFilter)(ExceptionFilter);
  83   // We record the user provided exception handler to be called for all the
  84   // exceptions unhandled by asan.
  85   Swap(ExceptionFilter, user_seh_handler);
  86   return ExceptionFilter;
  87 }
  88
  89 INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
  90   CHECK(REAL(RtlRaiseException));
  91   // This is a noreturn function, unless it's one of the exceptions raised to
  92   // communicate with the debugger, such as the one from OutputDebugString.
  93   if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
  94     __asan_handle_no_return();
  95   REAL(RtlRaiseException)(ExceptionRecord);
  96 }
  97
  98 INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
  99   CHECK(REAL(RaiseException));
 100   __asan_handle_no_return();
 101   REAL(RaiseException)(a, b, c, d);
 102 }
 103
 104 #ifdef _WIN64
 105
 106 INTERCEPTOR_WINAPI(int, __C_specific_handler, void *a, void *b, void *c, void *d) {  // NOLINT
 107   CHECK(REAL(__C_specific_handler));
 108   __asan_handle_no_return();
 109   return REAL(__C_specific_handler)(a, b, c, d);
 110 }
 111
 112 #else
 113
 114 INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
 115   CHECK(REAL(_except_handler3));
 116   __asan_handle_no_return();
 117   return REAL(_except_handler3)(a, b, c, d);
 118 }
 119
 120 #if ASAN_DYNAMIC
 121 // This handler is named differently in -MT and -MD CRTs.
 122 #define _except_handler4 _except_handler4_common
 123 #endif
 124 INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
 125   CHECK(REAL(_except_handler4));
 126   __asan_handle_no_return();
 127   return REAL(_except_handler4)(a, b, c, d);
 128 }
 129 #endif
 130
 131 static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
 132   AsanThread *t = (AsanThread*)arg;
 133   SetCurrentThread(t);
 134   return t->ThreadStart(GetTid(), /* signal_thread_is_registered */ nullptr);
 135 }
 136
 137 INTERCEPTOR_WINAPI(DWORD, CreateThread,
 138                    void* security, uptr stack_size,
 139                    DWORD (__stdcall *start_routine)(void*), void* arg,
 140                    DWORD thr_flags, void* tid) {
 141   // Strict init-order checking is thread-hostile.
 142   if (flags()->strict_init_order)
 143     StopInitOrderChecking();
 144   GET_STACK_TRACE_THREAD;
 145   // FIXME: The CreateThread interceptor is not the same as a pthread_create
 146   // one.  This is a bandaid fix for PR22025.
 147   bool detached = false;  // FIXME: how can we determine it on Windows?
 148   u32 current_tid = GetCurrentTidOrInvalid();
 149   AsanThread *t =
 150         AsanThread::Create(start_routine, arg, current_tid, &stack, detached);
 151   return REAL(CreateThread)(security, stack_size,
 152                             asan_thread_start, t, thr_flags, tid);
 153 }
 154
 155 // }}}
 156
 157 namespace __asan {
 158
 159 void InitializePlatformInterceptors() {
 160   // The interceptors were not designed to be removable, so we have to keep this
 161   // module alive for the life of the process.
 162   HMODULE pinned;
 163   CHECK(GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
 164                            GET_MODULE_HANDLE_EX_FLAG_PIN,
 165                            (LPCWSTR)&InitializePlatformInterceptors,
 166                            &pinned));
 167
 168   ASAN_INTERCEPT_FUNC(CreateThread);
 169   ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
 170
 171 #ifdef _WIN64
 172   ASAN_INTERCEPT_FUNC(__C_specific_handler);
 173 #else
 174   ASAN_INTERCEPT_FUNC(_except_handler3);
 175   ASAN_INTERCEPT_FUNC(_except_handler4);
 176 #endif
 177
 178   // Try to intercept kernel32!RaiseException, and if that fails, intercept
 179   // ntdll!RtlRaiseException instead.
 180   if (!::__interception::OverrideFunction("RaiseException",
 181                                           (uptr)WRAP(RaiseException),
 182                                           (uptr *)&REAL(RaiseException))) {
 183     CHECK(::__interception::OverrideFunction("RtlRaiseException",
 184                                              (uptr)WRAP(RtlRaiseException),
 185                                              (uptr *)&REAL(RtlRaiseException)));
 186   }
 187 }
 188
 189 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 190   UNIMPLEMENTED();
 191 }
 192
 193 // ---------------------- TSD ---------------- {{{
 194 static bool tsd_key_inited = false;
 195
 196 static __declspec(thread) void *fake_tsd = 0;
 197
 198 void AsanTSDInit(void (*destructor)(void *tsd)) {
 199   // FIXME: we're ignoring the destructor for now.
 200   tsd_key_inited = true;
 201 }
 202
 203 void *AsanTSDGet() {
 204   CHECK(tsd_key_inited);
 205   return fake_tsd;
 206 }
 207
 208 void AsanTSDSet(void *tsd) {
 209   CHECK(tsd_key_inited);
 210   fake_tsd = tsd;
 211 }
 212
 213 void PlatformTSDDtor(void *tsd) {
 214   AsanThread::TSDDtor(tsd);
 215 }
 216 // }}}
 217
 218 // ---------------------- Various stuff ---------------- {{{
 219 void *AsanDoesNotSupportStaticLinkage() {
 220 #if defined(_DEBUG)
 221 #error Please build the runtime with a non-debug CRT: /MD or /MT
 222 #endif
 223   return 0;
 224 }
 225
 226 uptr FindDynamicShadowStart() {
 227   uptr granularity = GetMmapGranularity();
 228   uptr alignment = 8 * granularity;
 229   uptr left_padding = granularity;
 230   uptr space_size = kHighShadowEnd + left_padding;
 231   uptr shadow_start = FindAvailableMemoryRange(space_size, alignment,
 232                                                granularity, nullptr, nullptr);
 233   CHECK_NE((uptr)0, shadow_start);
 234   CHECK(IsAligned(shadow_start, alignment));
 235   return shadow_start;
 236 }
 237
 238 void AsanCheckDynamicRTPrereqs() {}
 239
 240 void AsanCheckIncompatibleRT() {}
 241
 242 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 243   UNIMPLEMENTED();
 244 }
 245
 246 void AsanOnDeadlySignal(int, void *siginfo, void *context) {
 247   UNIMPLEMENTED();
 248 }
 249
 250 #if SANITIZER_WINDOWS64
 251 // Exception handler for dealing with shadow memory.
 252 static LONG CALLBACK
 253 ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
 254   uptr page_size = GetPageSizeCached();
 255   // Only handle access violations.
 256   if (exception_pointers->ExceptionRecord->ExceptionCode !=
 257       EXCEPTION_ACCESS_VIOLATION) {
 258     return EXCEPTION_CONTINUE_SEARCH;
 259   }
 260
 261   // Only handle access violations that land within the shadow memory.
 262   uptr addr =
 263       (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
 264
 265   // Check valid shadow range.
 266   if (!AddrIsInShadow(addr)) return EXCEPTION_CONTINUE_SEARCH;
 267
 268   // This is an access violation while trying to read from the shadow. Commit
 269   // the relevant page and let execution continue.
 270
 271   // Determine the address of the page that is being accessed.
 272   uptr page = RoundDownTo(addr, page_size);
 273
 274   // Commit the page.
 275   uptr result =
 276       (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
 277   if (result != page) return EXCEPTION_CONTINUE_SEARCH;
 278
 279   // The page mapping succeeded, so continue execution as usual.
 280   return EXCEPTION_CONTINUE_EXECUTION;
 281 }
 282
 283 #endif
 284
 285 void InitializePlatformExceptionHandlers() {
 286 #if SANITIZER_WINDOWS64
 287   // On Win64, we map memory on demand with access violation handler.
 288   // Install our exception handler.
 289   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 290 #endif
 291 }
 292
 293 bool IsSystemHeapAddress(uptr addr) {
 294   return ::HeapValidate(GetProcessHeap(), 0, (void*)addr) != FALSE;
 295 }
 296
 297 // We want to install our own exception handler (EH) to print helpful reports
 298 // on access violations and whatnot.  Unfortunately, the CRT initializers assume
 299 // they are run before any user code and drop any previously-installed EHs on
 300 // the floor, so we can't install our handler inside __asan_init.
 301 // (See crt0dat.c in the CRT sources for the details)
 302 //
 303 // Things get even more complicated with the dynamic runtime, as it finishes its
 304 // initialization before the .exe module CRT begins to initialize.
 305 //
 306 // For the static runtime (-MT), it's enough to put a callback to
 307 // __asan_set_seh_filter in the last section for C initializers.
 308 //
 309 // For the dynamic runtime (-MD), we want link the same
 310 // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
 311 // will be called for each instrumented module.  This ensures that at least one
 312 // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
 313 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 314 int __asan_set_seh_filter() {
 315   // We should only store the previous handler if it's not our own handler in
 316   // order to avoid loops in the EH chain.
 317   auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
 318   if (prev_seh_handler != &SEHHandler)
 319     default_seh_handler = prev_seh_handler;
 320   return 0;
 321 }
 322
 323 #if !ASAN_DYNAMIC
 324 // The CRT runs initializers in this order:
 325 // - C initializers, from XIA to XIZ
 326 // - C++ initializers, from XCA to XCZ
 327 // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
 328 // near the end of C initialization. Starting in 2015, it was moved to the
 329 // beginning of C++ initialization. We set our priority to XCAB to run
 330 // immediately after the CRT runs. This way, our exception filter is called
 331 // first and we can delegate to their filter if appropriate.
 332 #pragma section(".CRT$XCAB", long, read)  // NOLINT
 333 __declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
 334     __asan_set_seh_filter;
 335
 336 // Piggyback on the TLS initialization callback directory to initialize asan as
 337 // early as possible. Initializers in .CRT$XL* are called directly by ntdll,
 338 // which run before the CRT. Users also add code to .CRT$XLC, so it's important
 339 // to run our initializers first.
 340 static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
 341   if (reason == DLL_PROCESS_ATTACH) __asan_init();
 342 }
 343
 344 #pragma section(".CRT$XLAB", long, read)  // NOLINT
 345 __declspec(allocate(".CRT$XLAB")) void (NTAPI *__asan_tls_init)(void *,
 346     unsigned long, void *) = asan_thread_init;
 347 #endif
 348
 349 WIN_FORCE_LINK(__asan_dso_reg_hook)
 350
 351 // }}}
 352 }  // namespace __asan
 353
 354 #endif  // SANITIZER_WINDOWS