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
  29 using namespace __asan;  // NOLINT
  30
  31 extern "C" {
  32 SANITIZER_INTERFACE_ATTRIBUTE
  33 int __asan_should_detect_stack_use_after_return() {
  34   __asan_init();
  35   return __asan_option_detect_stack_use_after_return;
  36 }
  37
  38 SANITIZER_INTERFACE_ATTRIBUTE
  39 uptr __asan_get_shadow_memory_dynamic_address() {
  40   __asan_init();
  41   return __asan_shadow_memory_dynamic_address;
  42 }
  43
  44 // -------------------- A workaround for the absence of weak symbols ----- {{{
  45 // We don't have a direct equivalent of weak symbols when using MSVC, but we can
  46 // use the /alternatename directive to tell the linker to default a specific
  47 // symbol to a specific value, which works nicely for allocator hooks and
  48 // __asan_default_options().
  49 void __sanitizer_default_malloc_hook(void *ptr, uptr size) { }
  50 void __sanitizer_default_free_hook(void *ptr) { }
  51 const char* __asan_default_default_options() { return ""; }
  52 const char* __asan_default_default_suppressions() { return ""; }
  53 void __asan_default_on_error() {}
  54 // 64-bit msvc will not prepend an underscore for symbols.
  55 #ifdef _WIN64
  56 #pragma comment(linker, "/alternatename:__sanitizer_malloc_hook=__sanitizer_default_malloc_hook")  // NOLINT
  57 #pragma comment(linker, "/alternatename:__sanitizer_free_hook=__sanitizer_default_free_hook")      // NOLINT
  58 #pragma comment(linker, "/alternatename:__asan_default_options=__asan_default_default_options")    // NOLINT
  59 #pragma comment(linker, "/alternatename:__asan_default_suppressions=__asan_default_default_suppressions")    // NOLINT
  60 #pragma comment(linker, "/alternatename:__asan_on_error=__asan_default_on_error")                  // NOLINT
  61 #else
  62 #pragma comment(linker, "/alternatename:___sanitizer_malloc_hook=___sanitizer_default_malloc_hook")  // NOLINT
  63 #pragma comment(linker, "/alternatename:___sanitizer_free_hook=___sanitizer_default_free_hook")      // NOLINT
  64 #pragma comment(linker, "/alternatename:___asan_default_options=___asan_default_default_options")    // NOLINT
  65 #pragma comment(linker, "/alternatename:___asan_default_suppressions=___asan_default_default_suppressions")    // NOLINT
  66 #pragma comment(linker, "/alternatename:___asan_on_error=___asan_default_on_error")                  // NOLINT
  67 #endif
  68 // }}}
  69 }  // extern "C"
  70
  71 // ---------------------- Windows-specific interceptors ---------------- {{{
  72 INTERCEPTOR_WINAPI(void, RtlRaiseException, EXCEPTION_RECORD *ExceptionRecord) {
  73   CHECK(REAL(RtlRaiseException));
  74   // This is a noreturn function, unless it's one of the exceptions raised to
  75   // communicate with the debugger, such as the one from OutputDebugString.
  76   if (ExceptionRecord->ExceptionCode != DBG_PRINTEXCEPTION_C)
  77     __asan_handle_no_return();
  78   REAL(RtlRaiseException)(ExceptionRecord);
  79 }
  80
  81 INTERCEPTOR_WINAPI(void, RaiseException, void *a, void *b, void *c, void *d) {
  82   CHECK(REAL(RaiseException));
  83   __asan_handle_no_return();
  84   REAL(RaiseException)(a, b, c, d);
  85 }
  86
  87 #ifdef _WIN64
  88
  89 INTERCEPTOR_WINAPI(int, __C_specific_handler, void *a, void *b, void *c, void *d) {  // NOLINT
  90   CHECK(REAL(__C_specific_handler));
  91   __asan_handle_no_return();
  92   return REAL(__C_specific_handler)(a, b, c, d);
  93 }
  94
  95 #else
  96
  97 INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
  98   CHECK(REAL(_except_handler3));
  99   __asan_handle_no_return();
 100   return REAL(_except_handler3)(a, b, c, d);
 101 }
 102
 103 #if ASAN_DYNAMIC
 104 // This handler is named differently in -MT and -MD CRTs.
 105 #define _except_handler4 _except_handler4_common
 106 #endif
 107 INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
 108   CHECK(REAL(_except_handler4));
 109   __asan_handle_no_return();
 110   return REAL(_except_handler4)(a, b, c, d);
 111 }
 112 #endif
 113
 114 static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
 115   AsanThread *t = (AsanThread*)arg;
 116   SetCurrentThread(t);
 117   return t->ThreadStart(GetTid(), /* signal_thread_is_registered */ nullptr);
 118 }
 119
 120 INTERCEPTOR_WINAPI(DWORD, CreateThread,
 121                    void* security, uptr stack_size,
 122                    DWORD (__stdcall *start_routine)(void*), void* arg,
 123                    DWORD thr_flags, void* tid) {
 124   // Strict init-order checking is thread-hostile.
 125   if (flags()->strict_init_order)
 126     StopInitOrderChecking();
 127   GET_STACK_TRACE_THREAD;
 128   // FIXME: The CreateThread interceptor is not the same as a pthread_create
 129   // one.  This is a bandaid fix for PR22025.
 130   bool detached = false;  // FIXME: how can we determine it on Windows?
 131   u32 current_tid = GetCurrentTidOrInvalid();
 132   AsanThread *t =
 133         AsanThread::Create(start_routine, arg, current_tid, &stack, detached);
 134   return REAL(CreateThread)(security, stack_size,
 135                             asan_thread_start, t, thr_flags, tid);
 136 }
 137
 138 // }}}
 139
 140 namespace __asan {
 141
 142 void InitializePlatformInterceptors() {
 143   ASAN_INTERCEPT_FUNC(CreateThread);
 144
 145 #ifdef _WIN64
 146   ASAN_INTERCEPT_FUNC(__C_specific_handler);
 147 #else
 148   ASAN_INTERCEPT_FUNC(_except_handler3);
 149   ASAN_INTERCEPT_FUNC(_except_handler4);
 150 #endif
 151
 152   // Try to intercept kernel32!RaiseException, and if that fails, intercept
 153   // ntdll!RtlRaiseException instead.
 154   if (!::__interception::OverrideFunction("RaiseException",
 155                                           (uptr)WRAP(RaiseException),
 156                                           (uptr *)&REAL(RaiseException))) {
 157     CHECK(::__interception::OverrideFunction("RtlRaiseException",
 158                                              (uptr)WRAP(RtlRaiseException),
 159                                              (uptr *)&REAL(RtlRaiseException)));
 160   }
 161 }
 162
 163 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 164   UNIMPLEMENTED();
 165 }
 166
 167 // ---------------------- TSD ---------------- {{{
 168 static bool tsd_key_inited = false;
 169
 170 static __declspec(thread) void *fake_tsd = 0;
 171
 172 void AsanTSDInit(void (*destructor)(void *tsd)) {
 173   // FIXME: we're ignoring the destructor for now.
 174   tsd_key_inited = true;
 175 }
 176
 177 void *AsanTSDGet() {
 178   CHECK(tsd_key_inited);
 179   return fake_tsd;
 180 }
 181
 182 void AsanTSDSet(void *tsd) {
 183   CHECK(tsd_key_inited);
 184   fake_tsd = tsd;
 185 }
 186
 187 void PlatformTSDDtor(void *tsd) {
 188   AsanThread::TSDDtor(tsd);
 189 }
 190 // }}}
 191
 192 // ---------------------- Various stuff ---------------- {{{
 193 void *AsanDoesNotSupportStaticLinkage() {
 194 #if defined(_DEBUG)
 195 #error Please build the runtime with a non-debug CRT: /MD or /MT
 196 #endif
 197   return 0;
 198 }
 199
 200 void AsanCheckDynamicRTPrereqs() {}
 201
 202 void AsanCheckIncompatibleRT() {}
 203
 204 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 205   UNIMPLEMENTED();
 206 }
 207
 208 void AsanOnDeadlySignal(int, void *siginfo, void *context) {
 209   UNIMPLEMENTED();
 210 }
 211
 212 #if SANITIZER_WINDOWS64
 213 // Exception handler for dealing with shadow memory.
 214 static LONG CALLBACK
 215 ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
 216   uptr page_size = GetPageSizeCached();
 217   // Only handle access violations.
 218   if (exception_pointers->ExceptionRecord->ExceptionCode !=
 219       EXCEPTION_ACCESS_VIOLATION) {
 220     return EXCEPTION_CONTINUE_SEARCH;
 221   }
 222
 223   // Only handle access violations that land within the shadow memory.
 224   uptr addr =
 225       (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
 226
 227   // Check valid shadow range.
 228   if (!AddrIsInShadow(addr)) return EXCEPTION_CONTINUE_SEARCH;
 229
 230   // This is an access violation while trying to read from the shadow. Commit
 231   // the relevant page and let execution continue.
 232
 233   // Determine the address of the page that is being accessed.
 234   uptr page = RoundDownTo(addr, page_size);
 235
 236   // Query the existing page.
 237   MEMORY_BASIC_INFORMATION mem_info = {};
 238   if (::VirtualQuery((LPVOID)page, &mem_info, sizeof(mem_info)) == 0)
 239     return EXCEPTION_CONTINUE_SEARCH;
 240
 241   // Commit the page.
 242   uptr result =
 243       (uptr)::VirtualAlloc((LPVOID)page, page_size, MEM_COMMIT, PAGE_READWRITE);
 244   if (result != page) return EXCEPTION_CONTINUE_SEARCH;
 245
 246   // The page mapping succeeded, so continue execution as usual.
 247   return EXCEPTION_CONTINUE_EXECUTION;
 248 }
 249
 250 #endif
 251
 252 void InitializePlatformExceptionHandlers() {
 253 #if SANITIZER_WINDOWS64
 254   // On Win64, we map memory on demand with access violation handler.
 255   // Install our exception handler.
 256   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 257 #endif
 258 }
 259
 260 static LPTOP_LEVEL_EXCEPTION_FILTER default_seh_handler;
 261
 262 // Check based on flags if we should report this exception.
 263 static bool ShouldReportDeadlyException(unsigned code) {
 264   switch (code) {
 265     case EXCEPTION_ACCESS_VIOLATION:
 266     case EXCEPTION_IN_PAGE_ERROR:
 267       return common_flags()->handle_segv;
 268     case EXCEPTION_BREAKPOINT:
 269     case EXCEPTION_ILLEGAL_INSTRUCTION: {
 270       return common_flags()->handle_sigill;
 271     }
 272   }
 273   return false;
 274 }
 275
 276 // Return the textual name for this exception.
 277 const char *DescribeSignalOrException(int signo) {
 278   unsigned code = signo;
 279   // Get the string description of the exception if this is a known deadly
 280   // exception.
 281   switch (code) {
 282     case EXCEPTION_ACCESS_VIOLATION:
 283       return "access-violation";
 284     case EXCEPTION_IN_PAGE_ERROR:
 285       return "in-page-error";
 286     case EXCEPTION_BREAKPOINT:
 287       return "breakpoint";
 288     case EXCEPTION_ILLEGAL_INSTRUCTION:
 289       return "illegal-instruction";
 290   }
 291   return nullptr;
 292 }
 293
 294 static long WINAPI SEHHandler(EXCEPTION_POINTERS *info) {
 295   EXCEPTION_RECORD *exception_record = info->ExceptionRecord;
 296   CONTEXT *context = info->ContextRecord;
 297
 298   if (ShouldReportDeadlyException(exception_record->ExceptionCode)) {
 299     SignalContext sig = SignalContext::Create(exception_record, context);
 300     ReportDeadlySignal(exception_record->ExceptionCode, sig);
 301   }
 302
 303   // FIXME: Handle EXCEPTION_STACK_OVERFLOW here.
 304
 305   return default_seh_handler(info);
 306 }
 307
 308 // We want to install our own exception handler (EH) to print helpful reports
 309 // on access violations and whatnot.  Unfortunately, the CRT initializers assume
 310 // they are run before any user code and drop any previously-installed EHs on
 311 // the floor, so we can't install our handler inside __asan_init.
 312 // (See crt0dat.c in the CRT sources for the details)
 313 //
 314 // Things get even more complicated with the dynamic runtime, as it finishes its
 315 // initialization before the .exe module CRT begins to initialize.
 316 //
 317 // For the static runtime (-MT), it's enough to put a callback to
 318 // __asan_set_seh_filter in the last section for C initializers.
 319 //
 320 // For the dynamic runtime (-MD), we want link the same
 321 // asan_dynamic_runtime_thunk.lib to all the modules, thus __asan_set_seh_filter
 322 // will be called for each instrumented module.  This ensures that at least one
 323 // __asan_set_seh_filter call happens after the .exe module CRT is initialized.
 324 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
 325 int __asan_set_seh_filter() {
 326   // We should only store the previous handler if it's not our own handler in
 327   // order to avoid loops in the EH chain.
 328   auto prev_seh_handler = SetUnhandledExceptionFilter(SEHHandler);
 329   if (prev_seh_handler != &SEHHandler)
 330     default_seh_handler = prev_seh_handler;
 331   return 0;
 332 }
 333
 334 #if !ASAN_DYNAMIC
 335 // The CRT runs initializers in this order:
 336 // - C initializers, from XIA to XIZ
 337 // - C++ initializers, from XCA to XCZ
 338 // Prior to 2015, the CRT set the unhandled exception filter at priority XIY,
 339 // near the end of C initialization. Starting in 2015, it was moved to the
 340 // beginning of C++ initialization. We set our priority to XCAB to run
 341 // immediately after the CRT runs. This way, our exception filter is called
 342 // first and we can delegate to their filter if appropriate.
 343 #pragma section(".CRT$XCAB", long, read)  // NOLINT
 344 __declspec(allocate(".CRT$XCAB"))
 345     int (*__intercept_seh)() = __asan_set_seh_filter;
 346 #endif
 347 // }}}
 348 }  // namespace __asan
 349
 350 #endif  // _WIN32