libsanitizer/hwasan/hwasan.cpp

   1 //===-- hwasan.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 HWAddressSanitizer.
  10 //
  11 // HWAddressSanitizer runtime.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "hwasan.h"
  15
  16 #include "hwasan_checks.h"
  17 #include "hwasan_dynamic_shadow.h"
  18 #include "hwasan_globals.h"
  19 #include "hwasan_mapping.h"
  20 #include "hwasan_poisoning.h"
  21 #include "hwasan_report.h"
  22 #include "hwasan_thread.h"
  23 #include "hwasan_thread_list.h"
  24 #include "sanitizer_common/sanitizer_atomic.h"
  25 #include "sanitizer_common/sanitizer_common.h"
  26 #include "sanitizer_common/sanitizer_flag_parser.h"
  27 #include "sanitizer_common/sanitizer_flags.h"
  28 #include "sanitizer_common/sanitizer_interface_internal.h"
  29 #include "sanitizer_common/sanitizer_libc.h"
  30 #include "sanitizer_common/sanitizer_procmaps.h"
  31 #include "sanitizer_common/sanitizer_stackdepot.h"
  32 #include "sanitizer_common/sanitizer_stacktrace.h"
  33 #include "sanitizer_common/sanitizer_symbolizer.h"
  34 #include "ubsan/ubsan_flags.h"
  35 #include "ubsan/ubsan_init.h"
  36
  37 // ACHTUNG! No system header includes in this file.
  38
  39 using namespace __sanitizer;
  40
  41 namespace __hwasan {
  42
  43 static Flags hwasan_flags;
  44
  45 Flags *flags() {
  46   return &hwasan_flags;
  47 }
  48
  49 int hwasan_inited = 0;
  50 int hwasan_instrumentation_inited = 0;
  51 bool hwasan_init_is_running;
  52
  53 int hwasan_report_count = 0;
  54
  55 uptr kLowShadowStart;
  56 uptr kLowShadowEnd;
  57 uptr kHighShadowStart;
  58 uptr kHighShadowEnd;
  59
  60 void Flags::SetDefaults() {
  61 #define HWASAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
  62 #include "hwasan_flags.inc"
  63 #undef HWASAN_FLAG
  64 }
  65
  66 static void RegisterHwasanFlags(FlagParser *parser, Flags *f) {
  67 #define HWASAN_FLAG(Type, Name, DefaultValue, Description) \
  68   RegisterFlag(parser, #Name, Description, &f->Name);
  69 #include "hwasan_flags.inc"
  70 #undef HWASAN_FLAG
  71 }
  72
  73 static void InitializeFlags() {
  74   SetCommonFlagsDefaults();
  75   {
  76     CommonFlags cf;
  77     cf.CopyFrom(*common_flags());
  78     cf.external_symbolizer_path = GetEnv("HWASAN_SYMBOLIZER_PATH");
  79     cf.malloc_context_size = 20;
  80     cf.handle_ioctl = true;
  81     // FIXME: test and enable.
  82     cf.check_printf = false;
  83     cf.intercept_tls_get_addr = true;
  84     cf.exitcode = 99;
  85     // 8 shadow pages ~512kB, small enough to cover common stack sizes.
  86     cf.clear_shadow_mmap_threshold = 4096 * (SANITIZER_ANDROID ? 2 : 8);
  87     // Sigtrap is used in error reporting.
  88     cf.handle_sigtrap = kHandleSignalExclusive;
  89
  90 #if SANITIZER_ANDROID
  91     // Let platform handle other signals. It is better at reporting them then we
  92     // are.
  93     cf.handle_segv = kHandleSignalNo;
  94     cf.handle_sigbus = kHandleSignalNo;
  95     cf.handle_abort = kHandleSignalNo;
  96     cf.handle_sigill = kHandleSignalNo;
  97     cf.handle_sigfpe = kHandleSignalNo;
  98 #endif
  99     OverrideCommonFlags(cf);
 100   }
 101
 102   Flags *f = flags();
 103   f->SetDefaults();
 104
 105   FlagParser parser;
 106   RegisterHwasanFlags(&parser, f);
 107   RegisterCommonFlags(&parser);
 108
 109 #if HWASAN_CONTAINS_UBSAN
 110   __ubsan::Flags *uf = __ubsan::flags();
 111   uf->SetDefaults();
 112
 113   FlagParser ubsan_parser;
 114   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
 115   RegisterCommonFlags(&ubsan_parser);
 116 #endif
 117
 118   // Override from user-specified string.
 119   if (__hwasan_default_options)
 120     parser.ParseString(__hwasan_default_options());
 121 #if HWASAN_CONTAINS_UBSAN
 122   const char *ubsan_default_options = __ubsan_default_options();
 123   ubsan_parser.ParseString(ubsan_default_options);
 124 #endif
 125
 126   parser.ParseStringFromEnv("HWASAN_OPTIONS");
 127 #if HWASAN_CONTAINS_UBSAN
 128   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
 129 #endif
 130
 131   InitializeCommonFlags();
 132
 133   if (Verbosity()) ReportUnrecognizedFlags();
 134
 135   if (common_flags()->help) parser.PrintFlagDescriptions();
 136 }
 137
 138 static void CheckUnwind() {
 139   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
 140   stack.Print();
 141 }
 142
 143 static void HwasanFormatMemoryUsage(InternalScopedString &s) {
 144   HwasanThreadList &thread_list = hwasanThreadList();
 145   auto thread_stats = thread_list.GetThreadStats();
 146   auto sds = StackDepotGetStats();
 147   AllocatorStatCounters asc;
 148   GetAllocatorStats(asc);
 149   s.append(
 150       "HWASAN pid: %d rss: %zd threads: %zd stacks: %zd"
 151       " thr_aux: %zd stack_depot: %zd uniq_stacks: %zd"
 152       " heap: %zd",
 153       internal_getpid(), GetRSS(), thread_stats.n_live_threads,
 154       thread_stats.total_stack_size,
 155       thread_stats.n_live_threads * thread_list.MemoryUsedPerThread(),
 156       sds.allocated, sds.n_uniq_ids, asc[AllocatorStatMapped]);
 157 }
 158
 159 #if SANITIZER_ANDROID
 160 static constexpr uptr kMemoryUsageBufferSize = 4096;
 161
 162 static char *memory_usage_buffer = nullptr;
 163
 164 static void InitMemoryUsage() {
 165   memory_usage_buffer =
 166       (char *)MmapOrDie(kMemoryUsageBufferSize, "memory usage string");
 167   CHECK(memory_usage_buffer);
 168   memory_usage_buffer[0] = '\0';
 169   DecorateMapping((uptr)memory_usage_buffer, kMemoryUsageBufferSize,
 170                   memory_usage_buffer);
 171 }
 172
 173 void UpdateMemoryUsage() {
 174   if (!flags()->export_memory_stats)
 175     return;
 176   if (!memory_usage_buffer)
 177     InitMemoryUsage();
 178   InternalScopedString s;
 179   HwasanFormatMemoryUsage(s);
 180   internal_strncpy(memory_usage_buffer, s.data(), kMemoryUsageBufferSize - 1);
 181   memory_usage_buffer[kMemoryUsageBufferSize - 1] = '\0';
 182 }
 183 #else
 184 void UpdateMemoryUsage() {}
 185 #endif
 186
 187 void HwasanAtExit() {
 188   if (common_flags()->print_module_map)
 189     DumpProcessMap();
 190   if (flags()->print_stats && (flags()->atexit || hwasan_report_count > 0))
 191     ReportStats();
 192   if (hwasan_report_count > 0) {
 193     // ReportAtExitStatistics();
 194     if (common_flags()->exitcode)
 195       internal__exit(common_flags()->exitcode);
 196   }
 197 }
 198
 199 void HandleTagMismatch(AccessInfo ai, uptr pc, uptr frame, void *uc,
 200                        uptr *registers_frame) {
 201   InternalMmapVector<BufferedStackTrace> stack_buffer(1);
 202   BufferedStackTrace *stack = stack_buffer.data();
 203   stack->Reset();
 204   stack->Unwind(pc, frame, uc, common_flags()->fast_unwind_on_fatal);
 205
 206   // The second stack frame contains the failure __hwasan_check function, as
 207   // we have a stack frame for the registers saved in __hwasan_tag_mismatch that
 208   // we wish to ignore. This (currently) only occurs on AArch64, as x64
 209   // implementations use SIGTRAP to implement the failure, and thus do not go
 210   // through the stack saver.
 211   if (registers_frame && stack->trace && stack->size > 0) {
 212     stack->trace++;
 213     stack->size--;
 214   }
 215
 216   bool fatal = flags()->halt_on_error || !ai.recover;
 217   ReportTagMismatch(stack, ai.addr, ai.size, ai.is_store, fatal,
 218                     registers_frame);
 219 }
 220
 221 void HwasanTagMismatch(uptr addr, uptr pc, uptr frame, uptr access_info,
 222                        uptr *registers_frame, size_t outsize) {
 223   __hwasan::AccessInfo ai;
 224   ai.is_store = access_info & 0x10;
 225   ai.is_load = !ai.is_store;
 226   ai.recover = access_info & 0x20;
 227   ai.addr = addr;
 228   if ((access_info & 0xf) == 0xf)
 229     ai.size = outsize;
 230   else
 231     ai.size = 1 << (access_info & 0xf);
 232
 233   HandleTagMismatch(ai, pc, frame, nullptr, registers_frame);
 234 }
 235
 236 Thread *GetCurrentThread() {
 237   uptr *ThreadLongPtr = GetCurrentThreadLongPtr();
 238   if (UNLIKELY(*ThreadLongPtr == 0))
 239     return nullptr;
 240   auto *R = (StackAllocationsRingBuffer *)ThreadLongPtr;
 241   return hwasanThreadList().GetThreadByBufferAddress((uptr)R->Next());
 242 }
 243
 244 } // namespace __hwasan
 245
 246 using namespace __hwasan;
 247
 248 void __sanitizer::BufferedStackTrace::UnwindImpl(
 249     uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
 250   Thread *t = GetCurrentThread();
 251   if (!t) {
 252     // The thread is still being created, or has already been destroyed.
 253     size = 0;
 254     return;
 255   }
 256   Unwind(max_depth, pc, bp, context, t->stack_top(), t->stack_bottom(),
 257          request_fast);
 258 }
 259
 260 static bool InitializeSingleGlobal(const hwasan_global &global) {
 261   uptr full_granule_size = RoundDownTo(global.size(), 16);
 262   TagMemoryAligned(global.addr(), full_granule_size, global.tag());
 263   if (global.size() % 16)
 264     TagMemoryAligned(global.addr() + full_granule_size, 16, global.size() % 16);
 265   return false;
 266 }
 267
 268 static void InitLoadedGlobals() {
 269   dl_iterate_phdr(
 270       [](dl_phdr_info *info, size_t /* size */, void * /* data */) -> int {
 271         for (const hwasan_global &global : HwasanGlobalsFor(
 272                  info->dlpi_addr, info->dlpi_phdr, info->dlpi_phnum))
 273           InitializeSingleGlobal(global);
 274         return 0;
 275       },
 276       nullptr);
 277 }
 278
 279 // Prepare to run instrumented code on the main thread.
 280 static void InitInstrumentation() {
 281   if (hwasan_instrumentation_inited) return;
 282
 283   InitializeOsSupport();
 284
 285   if (!InitShadow()) {
 286     Printf("FATAL: HWAddressSanitizer cannot mmap the shadow memory.\n");
 287     DumpProcessMap();
 288     Die();
 289   }
 290
 291   InitThreads();
 292
 293   hwasan_instrumentation_inited = 1;
 294 }
 295
 296 // Interface.
 297
 298 uptr __hwasan_shadow_memory_dynamic_address;  // Global interface symbol.
 299
 300 // This function was used by the old frame descriptor mechanism. We keep it
 301 // around to avoid breaking ABI.
 302 void __hwasan_init_frames(uptr beg, uptr end) {}
 303
 304 void __hwasan_init_static() {
 305   InitShadowGOT();
 306   InitInstrumentation();
 307
 308   // In the non-static code path we call dl_iterate_phdr here. But at this point
 309   // libc might not have been initialized enough for dl_iterate_phdr to work.
 310   // Fortunately, since this is a statically linked executable we can use the
 311   // linker-defined symbol __ehdr_start to find the only relevant set of phdrs.
 312   extern ElfW(Ehdr) __ehdr_start;
 313   for (const hwasan_global &global : HwasanGlobalsFor(
 314            /* base */ 0,
 315            reinterpret_cast<const ElfW(Phdr) *>(
 316                reinterpret_cast<const char *>(&__ehdr_start) +
 317                __ehdr_start.e_phoff),
 318            __ehdr_start.e_phnum))
 319     InitializeSingleGlobal(global);
 320 }
 321
 322 __attribute__((constructor(0))) void __hwasan_init() {
 323   CHECK(!hwasan_init_is_running);
 324   if (hwasan_inited) return;
 325   hwasan_init_is_running = 1;
 326   SanitizerToolName = "HWAddressSanitizer";
 327
 328   InitTlsSize();
 329
 330   CacheBinaryName();
 331   InitializeFlags();
 332
 333   // Install tool-specific callbacks in sanitizer_common.
 334   SetCheckUnwindCallback(CheckUnwind);
 335
 336   __sanitizer_set_report_path(common_flags()->log_path);
 337
 338   AndroidTestTlsSlot();
 339
 340   DisableCoreDumperIfNecessary();
 341
 342   InitInstrumentation();
 343   if constexpr (!SANITIZER_FUCHSIA) {
 344     // Fuchsia's libc provides a hook (__sanitizer_module_loaded) that runs on
 345     // the startup path which calls into __hwasan_library_loaded on all
 346     // initially loaded modules, so explicitly registering the globals here
 347     // isn't needed.
 348     InitLoadedGlobals();
 349   }
 350
 351   // Needs to be called here because flags()->random_tags might not have been
 352   // initialized when InitInstrumentation() was called.
 353   GetCurrentThread()->EnsureRandomStateInited();
 354
 355   SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
 356   // This may call libc -> needs initialized shadow.
 357   AndroidLogInit();
 358
 359   InitializeInterceptors();
 360   InstallDeadlySignalHandlers(HwasanOnDeadlySignal);
 361   InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
 362
 363   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
 364
 365   HwasanTSDInit();
 366   HwasanTSDThreadInit();
 367
 368   HwasanAllocatorInit();
 369   HwasanInstallAtForkHandler();
 370
 371 #if HWASAN_CONTAINS_UBSAN
 372   __ubsan::InitAsPlugin();
 373 #endif
 374
 375   VPrintf(1, "HWAddressSanitizer init done\n");
 376
 377   hwasan_init_is_running = 0;
 378   hwasan_inited = 1;
 379 }
 380
 381 void __hwasan_library_loaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
 382                              ElfW(Half) phnum) {
 383   for (const hwasan_global &global : HwasanGlobalsFor(base, phdr, phnum))
 384     InitializeSingleGlobal(global);
 385 }
 386
 387 void __hwasan_library_unloaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
 388                                ElfW(Half) phnum) {
 389   for (; phnum != 0; ++phdr, --phnum)
 390     if (phdr->p_type == PT_LOAD)
 391       TagMemory(base + phdr->p_vaddr, phdr->p_memsz, 0);
 392 }
 393
 394 void __hwasan_print_shadow(const void *p, uptr sz) {
 395   uptr ptr_raw = UntagAddr(reinterpret_cast<uptr>(p));
 396   uptr shadow_first = MemToShadow(ptr_raw);
 397   uptr shadow_last = MemToShadow(ptr_raw + sz - 1);
 398   Printf("HWASan shadow map for %zx .. %zx (pointer tag %x)\n", ptr_raw,
 399          ptr_raw + sz, GetTagFromPointer((uptr)p));
 400   for (uptr s = shadow_first; s <= shadow_last; ++s) {
 401     tag_t mem_tag = *reinterpret_cast<tag_t *>(s);
 402     uptr granule_addr = ShadowToMem(s);
 403     if (mem_tag && mem_tag < kShadowAlignment)
 404       Printf("  %zx: %02x(%02x)\n", granule_addr, mem_tag,
 405              *reinterpret_cast<tag_t *>(granule_addr + kShadowAlignment - 1));
 406     else
 407       Printf("  %zx: %02x\n", granule_addr, mem_tag);
 408   }
 409 }
 410
 411 sptr __hwasan_test_shadow(const void *p, uptr sz) {
 412   if (sz == 0)
 413     return -1;
 414   tag_t ptr_tag = GetTagFromPointer((uptr)p);
 415   uptr ptr_raw = UntagAddr(reinterpret_cast<uptr>(p));
 416   uptr shadow_first = MemToShadow(ptr_raw);
 417   uptr shadow_last = MemToShadow(ptr_raw + sz - 1);
 418   for (uptr s = shadow_first; s <= shadow_last; ++s)
 419     if (*(tag_t *)s != ptr_tag) {
 420       sptr offset = ShadowToMem(s) - ptr_raw;
 421       return offset < 0 ? 0 : offset;
 422     }
 423   return -1;
 424 }
 425
 426 u16 __sanitizer_unaligned_load16(const uu16 *p) {
 427   return *p;
 428 }
 429 u32 __sanitizer_unaligned_load32(const uu32 *p) {
 430   return *p;
 431 }
 432 u64 __sanitizer_unaligned_load64(const uu64 *p) {
 433   return *p;
 434 }
 435 void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
 436   *p = x;
 437 }
 438 void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
 439   *p = x;
 440 }
 441 void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
 442   *p = x;
 443 }
 444
 445 void __hwasan_loadN(uptr p, uptr sz) {
 446   CheckAddressSized<ErrorAction::Abort, AccessType::Load>(p, sz);
 447 }
 448 void __hwasan_load1(uptr p) {
 449   CheckAddress<ErrorAction::Abort, AccessType::Load, 0>(p);
 450 }
 451 void __hwasan_load2(uptr p) {
 452   CheckAddress<ErrorAction::Abort, AccessType::Load, 1>(p);
 453 }
 454 void __hwasan_load4(uptr p) {
 455   CheckAddress<ErrorAction::Abort, AccessType::Load, 2>(p);
 456 }
 457 void __hwasan_load8(uptr p) {
 458   CheckAddress<ErrorAction::Abort, AccessType::Load, 3>(p);
 459 }
 460 void __hwasan_load16(uptr p) {
 461   CheckAddress<ErrorAction::Abort, AccessType::Load, 4>(p);
 462 }
 463
 464 void __hwasan_loadN_noabort(uptr p, uptr sz) {
 465   CheckAddressSized<ErrorAction::Recover, AccessType::Load>(p, sz);
 466 }
 467 void __hwasan_load1_noabort(uptr p) {
 468   CheckAddress<ErrorAction::Recover, AccessType::Load, 0>(p);
 469 }
 470 void __hwasan_load2_noabort(uptr p) {
 471   CheckAddress<ErrorAction::Recover, AccessType::Load, 1>(p);
 472 }
 473 void __hwasan_load4_noabort(uptr p) {
 474   CheckAddress<ErrorAction::Recover, AccessType::Load, 2>(p);
 475 }
 476 void __hwasan_load8_noabort(uptr p) {
 477   CheckAddress<ErrorAction::Recover, AccessType::Load, 3>(p);
 478 }
 479 void __hwasan_load16_noabort(uptr p) {
 480   CheckAddress<ErrorAction::Recover, AccessType::Load, 4>(p);
 481 }
 482
 483 void __hwasan_storeN(uptr p, uptr sz) {
 484   CheckAddressSized<ErrorAction::Abort, AccessType::Store>(p, sz);
 485 }
 486 void __hwasan_store1(uptr p) {
 487   CheckAddress<ErrorAction::Abort, AccessType::Store, 0>(p);
 488 }
 489 void __hwasan_store2(uptr p) {
 490   CheckAddress<ErrorAction::Abort, AccessType::Store, 1>(p);
 491 }
 492 void __hwasan_store4(uptr p) {
 493   CheckAddress<ErrorAction::Abort, AccessType::Store, 2>(p);
 494 }
 495 void __hwasan_store8(uptr p) {
 496   CheckAddress<ErrorAction::Abort, AccessType::Store, 3>(p);
 497 }
 498 void __hwasan_store16(uptr p) {
 499   CheckAddress<ErrorAction::Abort, AccessType::Store, 4>(p);
 500 }
 501
 502 void __hwasan_storeN_noabort(uptr p, uptr sz) {
 503   CheckAddressSized<ErrorAction::Recover, AccessType::Store>(p, sz);
 504 }
 505 void __hwasan_store1_noabort(uptr p) {
 506   CheckAddress<ErrorAction::Recover, AccessType::Store, 0>(p);
 507 }
 508 void __hwasan_store2_noabort(uptr p) {
 509   CheckAddress<ErrorAction::Recover, AccessType::Store, 1>(p);
 510 }
 511 void __hwasan_store4_noabort(uptr p) {
 512   CheckAddress<ErrorAction::Recover, AccessType::Store, 2>(p);
 513 }
 514 void __hwasan_store8_noabort(uptr p) {
 515   CheckAddress<ErrorAction::Recover, AccessType::Store, 3>(p);
 516 }
 517 void __hwasan_store16_noabort(uptr p) {
 518   CheckAddress<ErrorAction::Recover, AccessType::Store, 4>(p);
 519 }
 520
 521 void __hwasan_tag_memory(uptr p, u8 tag, uptr sz) {
 522   TagMemoryAligned(p, sz, tag);
 523 }
 524
 525 uptr __hwasan_tag_pointer(uptr p, u8 tag) {
 526   return AddTagToPointer(p, tag);
 527 }
 528
 529 void __hwasan_handle_longjmp(const void *sp_dst) {
 530   uptr dst = (uptr)sp_dst;
 531   // HWASan does not support tagged SP.
 532   CHECK(GetTagFromPointer(dst) == 0);
 533
 534   uptr sp = (uptr)__builtin_frame_address(0);
 535   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
 536   if (dst < sp || dst - sp > kMaxExpectedCleanupSize) {
 537     Report(
 538         "WARNING: HWASan is ignoring requested __hwasan_handle_longjmp: "
 539         "stack top: %p; target %p; distance: %p (%zd)\n"
 540         "False positive error reports may follow\n",
 541         (void *)sp, (void *)dst, dst - sp);
 542     return;
 543   }
 544   TagMemory(sp, dst - sp, 0);
 545 }
 546
 547 void __hwasan_handle_vfork(const void *sp_dst) {
 548   uptr sp = (uptr)sp_dst;
 549   Thread *t = GetCurrentThread();
 550   CHECK(t);
 551   uptr top = t->stack_top();
 552   uptr bottom = t->stack_bottom();
 553   if (top == 0 || bottom == 0 || sp < bottom || sp >= top) {
 554     Report(
 555         "WARNING: HWASan is ignoring requested __hwasan_handle_vfork: "
 556         "stack top: %zx; current %zx; bottom: %zx \n"
 557         "False positive error reports may follow\n",
 558         top, sp, bottom);
 559     return;
 560   }
 561   TagMemory(bottom, sp - bottom, 0);
 562 }
 563
 564 extern "C" void *__hwasan_extra_spill_area() {
 565   Thread *t = GetCurrentThread();
 566   return &t->vfork_spill();
 567 }
 568
 569 void __hwasan_print_memory_usage() {
 570   InternalScopedString s;
 571   HwasanFormatMemoryUsage(s);
 572   Printf("%s\n", s.data());
 573 }
 574
 575 static const u8 kFallbackTag = 0xBB & kTagMask;
 576
 577 u8 __hwasan_generate_tag() {
 578   Thread *t = GetCurrentThread();
 579   if (!t) return kFallbackTag;
 580   return t->GenerateRandomTag();
 581 }
 582
 583 void __hwasan_add_frame_record(u64 frame_record_info) {
 584   Thread *t = GetCurrentThread();
 585   if (t)
 586     t->stack_allocations()->push(frame_record_info);
 587 }
 588
 589 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 590 extern "C" {
 591 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 592 const char* __hwasan_default_options() { return ""; }
 593 }  // extern "C"
 594 #endif
 595
 596 extern "C" {
 597 SANITIZER_INTERFACE_ATTRIBUTE
 598 void __sanitizer_print_stack_trace() {
 599   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
 600   stack.Print();
 601 }
 602
 603 // Entry point for interoperability between __hwasan_tag_mismatch (ASM) and the
 604 // rest of the mismatch handling code (C++).
 605 void __hwasan_tag_mismatch4(uptr addr, uptr access_info, uptr *registers_frame,
 606                             size_t outsize) {
 607   __hwasan::HwasanTagMismatch(addr, (uptr)__builtin_return_address(0),
 608                               (uptr)__builtin_frame_address(0), access_info,
 609                               registers_frame, outsize);
 610 }
 611
 612 } // extern "C"