src/compiler-rt/lib/asan/asan_win.cc

   1 //===-- asan_win.cc -------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   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 <windows.h>
  19
  20 #include <stdlib.h>
  21
  22 #include "asan_globals_win.h"
  23 #include "asan_interceptors.h"
  24 #include "asan_internal.h"
  25 #include "asan_report.h"
  26 #include "asan_stack.h"
  27 #include "asan_thread.h"
  28 #include "asan_mapping.h"
  29 #include "sanitizer_common/sanitizer_libc.h"
  30 #include "sanitizer_common/sanitizer_mutex.h"
  31
  32 using namespace __asan;  // NOLINT
  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
  47 // -------------------- A workaround for the absence of weak symbols ----- {{{
  48 // We don't have a direct equivalent of weak symbols when using MSVC, but we can
  49 // use the /alternatename directive to tell the linker to default a specific
  50 // symbol to a specific value, which works nicely for allocator hooks and
  51 // __asan_default_options().
  52 void __sanitizer_default_malloc_hook(void *ptr, uptr size) { }
  53 void __sanitizer_default_free_hook(void *ptr) { }
  54 const char* __asan_default_default_options() { return ""; }
  55 const char* __asan_default_default_suppressions() { return ""; }
  56 void __asan_default_on_error() {}
  57 // 64-bit msvc will not prepend an underscore for symbols.
  58 #ifdef _WIN64
  59 #pragma comment(linker, "/alternatename:__sanitizer_malloc_hook=__sanitizer_default_malloc_hook")  // NOLINT
  60 #pragma comment(linker, "/alternatename:__sanitizer_free_hook=__sanitizer_default_free_hook")      // NOLINT
  61 #pragma comment(linker, "/alternatename:__asan_default_options=__asan_default_default_options")    // NOLINT
  62 #pragma comment(linker, "/alternatename:__asan_default_suppressions=__asan_default_default_suppressions")    // NOLINT
  63 #pragma comment(linker, "/alternatename:__asan_on_error=__asan_default_on_error")                  // NOLINT
  64 #else
  65 #pragma comment(linker, "/alternatename:___sanitizer_malloc_hook=___sanitizer_default_malloc_hook")  // NOLINT
  66 #pragma comment(linker, "/alternatename:___sanitizer_free_hook=___sanitizer_default_free_hook")      // NOLINT
  67 #pragma comment(linker, "/alternatename:___asan_default_options=___asan_default_default_options")    // NOLINT
  68 #pragma comment(linker, "/alternatename:___asan_default_suppressions=___asan_default_default_suppressions")    // NOLINT
  69 #pragma comment(linker, "/alternatename:___asan_on_error=___asan_default_on_error")                  // NOLINT
  70 #endif
  71 // }}}
  72 }  // extern "C"
  73
  74 // ---------------------- Windows-specific interceptors ---------------- {{{
  75 INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
  76   CHECK(REAL(RtlRaiseException));
  77   // This is a noreturn function, unless it's one of the exceptions raised to
  78   // communicate with the debugger, such as the one from OutputDebugString.
  79   if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
  80     __asan_handle_no_return();
  81   REAL(RtlRaiseException)(ExceptionRecord);
  82 }
  83
  84 INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
  85   CHECK(REAL(RaiseException));
  86   __asan_handle_no_return();
  87   REAL(RaiseException)(a, b, c, d);
  88 }
  89
  90 #ifdef _WIN64
  91
  92 INTERCEPTOR_WINAPI(int, __C_specific_handler, void *a, void *b, void *c, void *d) {  // NOLINT
  93   CHECK(REAL(__C_specific_handler));
  94   __asan_handle_no_return();
  95   return REAL(__C_specific_handler)(a, b, c, d);
  96 }
  97
  98 #else
  99
 100 INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
 101   CHECK(REAL(_except_handler3));
 102   __asan_handle_no_return();
 103   return REAL(_except_handler3)(a, b, c, d);
 104 }
 105
 106 #if ASAN_DYNAMIC
 107 // This handler is named differently in -MT and -MD CRTs.
 108 #define _except_handler4 _except_handler4_common
 109 #endif
 110 INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
 111   CHECK(REAL(_except_handler4));
 112   __asan_handle_no_return();
 113   return REAL(_except_handler4)(a, b, c, d);
 114 }
 115 #endif
 116
 117 static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
 118   AsanThread *t = (AsanThread*)arg;
 119   SetCurrentThread(t);
 120   return t->ThreadStart(GetTid(), /* signal_thread_is_registered */ nullptr);
 121 }
 122
 123 INTERCEPTOR_WINAPI(DWORD, CreateThread,
 124                    void* security, uptr stack_size,
 125                    DWORD (__stdcall *start_routine)(void*), void* arg,
 126                    DWORD thr_flags, void* tid) {
 127   // Strict init-order checking is thread-hostile.
 128   if (flags()->strict_init_order)
 129     StopInitOrderChecking();
 130   GET_STACK_TRACE_THREAD;
 131   // FIXME: The CreateThread interceptor is not the same as a pthread_create
 132   // one.  This is a bandaid fix for PR22025.
 133   bool detached = false;  // FIXME: how can we determine it on Windows?
 134   u32 current_tid = GetCurrentTidOrInvalid();
 135   AsanThread *t =
 136         AsanThread::Create(start_routine, arg, current_tid, &stack, detached);
 137   return REAL(CreateThread)(security, stack_size,
 138                             asan_thread_start, t, thr_flags, tid);
 139 }
 140
 141 // }}}
 142
 143 namespace __asan {
 144
 145 void InitializePlatformInterceptors() {
 146   ASAN_INTERCEPT_FUNC(CreateThread);
 147
 148 #ifdef _WIN64
 149   ASAN_INTERCEPT_FUNC(__C_specific_handler);
 150 #else
 151   ASAN_INTERCEPT_FUNC(_except_handler3);
 152   ASAN_INTERCEPT_FUNC(_except_handler4);
 153 #endif
 154
 155   // Try to intercept kernel32!RaiseException, and if that fails, intercept
 156   // ntdll!RtlRaiseException instead.
 157   if (!::__interception::OverrideFunction("RaiseException",
 158                                           (uptr)WRAP(RaiseException),
 159                                           (uptr *)&REAL(RaiseException))) {
 160     CHECK(::__interception::OverrideFunction("RtlRaiseException",
 161                                              (uptr)WRAP(RtlRaiseException),
 162                                              (uptr *)&REAL(RtlRaiseException)));
 163   }
 164 }
 165
 166 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 167   UNIMPLEMENTED();
 168 }
 169
 170 // ---------------------- TSD ---------------- {{{
 171 static bool tsd_key_inited = false;
 172
 173 static __declspec(thread) void *fake_tsd = 0;
 174
 175 void AsanTSDInit(void (*destructor)(void *tsd)) {
 176   // FIXME: we're ignoring the destructor for now.
 177   tsd_key_inited = true;
 178 }
 179
 180 void *AsanTSDGet() {
 181   CHECK(tsd_key_inited);
 182   return fake_tsd;
 183 }
 184
 185 void AsanTSDSet(void *tsd) {
 186   CHECK(tsd_key_inited);
 187   fake_tsd = tsd;
 188 }
 189
 190 void PlatformTSDDtor(void *tsd) {
 191   AsanThread::TSDDtor(tsd);
 192 }
 193 // }}}
 194
 195 // ---------------------- Various stuff ---------------- {{{
 196 void *AsanDoesNotSupportStaticLinkage() {
 197 #if defined(_DEBUG)
 198 #error Please build the runtime with a non-debug CRT: /MD or /MT
 199 #endif
 200   return 0;
 201 }
 202
 203 void AsanCheckDynamicRTPrereqs() {}
 204
 205 void AsanCheckIncompatibleRT() {}
 206
 207 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 208   UNIMPLEMENTED();
 209 }
 210
 211 void AsanOnDeadlySignal(int, void *siginfo, void *context) {
 212   UNIMPLEMENTED();
 213 }
 214
 215 #if SANITIZER_WINDOWS64
 216 // Exception handler for dealing with shadow memory.
 217 static LONG CALLBACK
 218 ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
 219   uptr page_size = GetPageSizeCached();
 220   // Only handle access violations.
 221   if (exception_pointers->ExceptionRecord->ExceptionCode !=
 222       EXCEPTION_ACCESS_VIOLATION) {
 223     return EXCEPTION_CONTINUE_SEARCH;
 224   }
 225
 226   // Only handle access violations that land within the shadow memory.
 227   uptr addr =
 228       (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
 229
 230   // Check valid shadow range.
 231   if (!AddrIsInShadow(addr)) return EXCEPTION_CONTINUE_SEARCH;
 232
 233   // This is an access violation while trying to read from the shadow. Commit
 234   // the relevant page and let execution continue.
 235
 236   // Determine the address of the page that is being accessed.
 237   uptr page = RoundDownTo(addr, page_size);
 238
 239   // Query the existing page.
 240   MEMORY_BASIC_INFORMATION mem_info = {};
 241   if (::VirtualQuery((LPVOID)page, &mem_info, sizeof(mem_info)) == 0)
 242     return EXCEPTION_CONTINUE_SEARCH;
 243
 244   // Commit the page.
 245   uptr result =
 246       (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
 247   if (result != page) return EXCEPTION_CONTINUE_SEARCH;
 248
 249   // The page mapping succeeded, so continue execution as usual.
 250   return EXCEPTION_CONTINUE_EXECUTION;
 251 }
 252
 253 #endif
 254
 255 void InitializePlatformExceptionHandlers() {
 256 #if SANITIZER_WINDOWS64
 257   // On Win64, we map memory on demand with access violation handler.
 258   // Install our exception handler.
 259   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 260 #endif
 261 }
 262
 263 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
 264
 265 // Check based on flags if we should report this exception.
 266 static bool ShouldReportDeadlyException(unsigned code) {
 267   switch (code) {
 268     case EXCEPTION_ACCESS_VIOLATION:
 269     case EXCEPTION_IN_PAGE_ERROR:
 270       return common_flags()->handle_segv;
 271     case EXCEPTION_BREAKPOINT:
 272     case EXCEPTION_ILLEGAL_INSTRUCTION: {
 273       return common_flags()->handle_sigill;
 274     }
 275   }
 276   return false;
 277 }
 278
 279 // Return the textual name for this exception.
 280 const char *DescribeSignalOrException(int signo) {
 281   unsigned code = signo;
 282   // Get the string description of the exception if this is a known deadly
 283   // exception.
 284   switch (code) {
 285     case EXCEPTION_ACCESS_VIOLATION:
 286       return "access-violation";
 287     case EXCEPTION_IN_PAGE_ERROR:
 288       return "in-page-error";
 289     case EXCEPTION_BREAKPOINT:
 290       return "breakpoint";
 291     case EXCEPTION_ILLEGAL_INSTRUCTION:
 292       return "illegal-instruction";
 293   }
 294   return nullptr;
 295 }
 296
 297 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 298 long __asan_unhandled_exception_filter(EXCEPTION_POINTERS *info) {
 299   EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
 300   CONTEXT *context = info->ContextRecord;
 301
 302   // Continue the search if the signal wasn't deadly.
 303   if (!ShouldReportDeadlyException(exception_record->ExceptionCode))
 304     return EXCEPTION_CONTINUE_SEARCH;
 305   // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
 306
 307   SignalContext sig = SignalContext::Create(exception_record, context);
 308   ReportDeadlySignal(exception_record->ExceptionCode, sig);
 309   UNREACHABLE("returned from reporting deadly signal");
 310 }
 311
 312 static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
 313   __asan_unhandled_exception_filter(info);
 314
 315   // Bubble out to the default exception filter.
 316   return default_seh_handler(info);
 317 }
 318
 319 // We want to install our own exception handler (EH) to print helpful reports
 320 // on access violations and whatnot.  Unfortunately, the CRT initializers assume
 321 // they are run before any user code and drop any previously-installed EHs on
 322 // the floor, so we can't install our handler inside __asan_init.
 323 // (See crt0dat.c in the CRT sources for the details)
 324 //
 325 // Things get even more complicated with the dynamic runtime, as it finishes its
 326 // initialization before the .exe module CRT begins to initialize.
 327 //
 328 // For the static runtime (-MT), it's enough to put a callback to
 329 // __asan_set_seh_filter in the last section for C initializers.
 330 //
 331 // For the dynamic runtime (-MD), we want link the same
 332 // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
 333 // will be called for each instrumented module.  This ensures that at least one
 334 // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
 335 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 336 int __asan_set_seh_filter() {
 337   // We should only store the previous handler if it's not our own handler in
 338   // order to avoid loops in the EH chain.
 339   auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
 340   if (prev_seh_handler != &SEHHandler)
 341     default_seh_handler = prev_seh_handler;
 342   return 0;
 343 }
 344
 345 #if !ASAN_DYNAMIC
 346 // The CRT runs initializers in this order:
 347 // - C initializers, from XIA to XIZ
 348 // - C++ initializers, from XCA to XCZ
 349 // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
 350 // near the end of C initialization. Starting in 2015, it was moved to the
 351 // beginning of C++ initialization. We set our priority to XCAB to run
 352 // immediately after the CRT runs. This way, our exception filter is called
 353 // first and we can delegate to their filter if appropriate.
 354 #pragma section(".CRT$XCAB", long, read)  // NOLINT
 355 __declspec(allocate(".CRT$XCAB")) int (*__intercept_seh)() =
 356     __asan_set_seh_filter;
 357
 358 // Piggyback on the TLS initialization callback directory to initialize asan as
 359 // early as possible. Initializers in .CRT$XL* are called directly by ntdll,
 360 // which run before the CRT. Users also add code to .CRT$XLC, so it's important
 361 // to run our initializers first.
 362 static void NTAPI asan_thread_init(void *module, DWORD reason, void *reserved) {
 363   if (reason == DLL_PROCESS_ATTACH) __asan_init();
 364 }
 365
 366 #pragma section(".CRT$XLAB", long, read)  // NOLINT
 367 __declspec(allocate(".CRT$XLAB")) void (NTAPI *__asan_tls_init)(void *,
 368     unsigned long, void *) = asan_thread_init;
 369 #endif
 370
 371 ASAN_LINK_GLOBALS_WIN()
 372
 373 // }}}
 374 }  // namespace __asan
 375
 376 #endif  // SANITIZER_WINDOWS