libsanitizer/asan/asan_errors.cpp

   1 //===-- asan_errors.cpp -----------------------------------------*- C++ -*-===//
   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 // ASan implementation for error structures.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "asan_errors.h"
  15 #include "asan_descriptions.h"
  16 #include "asan_mapping.h"
  17 #include "asan_report.h"
  18 #include "asan_stack.h"
  19 #include "sanitizer_common/sanitizer_stackdepot.h"
  20
  21 namespace __asan {
  22
  23 static void OnStackUnwind(const SignalContext &sig,
  24                           const void *callback_context,
  25                           BufferedStackTrace *stack) {
  26   bool fast = common_flags()->fast_unwind_on_fatal;
  27 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
  28   // On FreeBSD the slow unwinding that leverages _Unwind_Backtrace()
  29   // yields the call stack of the signal's handler and not of the code
  30   // that raised the signal (as it does on Linux).
  31   fast = true;
  32 #endif
  33   // Tests and maybe some users expect that scariness is going to be printed
  34   // just before the stack. As only asan has scariness score we have no
  35   // corresponding code in the sanitizer_common and we use this callback to
  36   // print it.
  37   static_cast<const ScarinessScoreBase *>(callback_context)->Print();
  38   stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
  39                 fast);
  40 }
  41
  42 void ErrorDeadlySignal::Print() {
  43   ReportDeadlySignal(signal, tid, &OnStackUnwind, &scariness);
  44 }
  45
  46 void ErrorDoubleFree::Print() {
  47   Decorator d;
  48   Printf("%s", d.Error());
  49   Report(
  50       "ERROR: AddressSanitizer: attempting %s on %p in thread %s:\n",
  51       scariness.GetDescription(), addr_description.addr,
  52       AsanThreadIdAndName(tid).c_str());
  53   Printf("%s", d.Default());
  54   scariness.Print();
  55   GET_STACK_TRACE_FATAL(second_free_stack->trace[0],
  56                         second_free_stack->top_frame_bp);
  57   stack.Print();
  58   addr_description.Print();
  59   ReportErrorSummary(scariness.GetDescription(), &stack);
  60 }
  61
  62 void ErrorNewDeleteTypeMismatch::Print() {
  63   Decorator d;
  64   Printf("%s", d.Error());
  65   Report(
  66       "ERROR: AddressSanitizer: %s on %p in thread %s:\n",
  67       scariness.GetDescription(), addr_description.addr,
  68       AsanThreadIdAndName(tid).c_str());
  69   Printf("%s  object passed to delete has wrong type:\n", d.Default());
  70   if (delete_size != 0) {
  71     Printf(
  72         "  size of the allocated type:   %zd bytes;\n"
  73         "  size of the deallocated type: %zd bytes.\n",
  74         addr_description.chunk_access.chunk_size, delete_size);
  75   }
  76   const uptr user_alignment =
  77       addr_description.chunk_access.user_requested_alignment;
  78   if (delete_alignment != user_alignment) {
  79     char user_alignment_str[32];
  80     char delete_alignment_str[32];
  81     internal_snprintf(user_alignment_str, sizeof(user_alignment_str),
  82                       "%zd bytes", user_alignment);
  83     internal_snprintf(delete_alignment_str, sizeof(delete_alignment_str),
  84                       "%zd bytes", delete_alignment);
  85     static const char *kDefaultAlignment = "default-aligned";
  86     Printf(
  87         "  alignment of the allocated type:   %s;\n"
  88         "  alignment of the deallocated type: %s.\n",
  89         user_alignment > 0 ? user_alignment_str : kDefaultAlignment,
  90         delete_alignment > 0 ? delete_alignment_str : kDefaultAlignment);
  91   }
  92   CHECK_GT(free_stack->size, 0);
  93   scariness.Print();
  94   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
  95   stack.Print();
  96   addr_description.Print();
  97   ReportErrorSummary(scariness.GetDescription(), &stack);
  98   Report(
  99       "HINT: if you don't care about these errors you may set "
 100       "ASAN_OPTIONS=new_delete_type_mismatch=0\n");
 101 }
 102
 103 void ErrorFreeNotMalloced::Print() {
 104   Decorator d;
 105   Printf("%s", d.Error());
 106   Report(
 107       "ERROR: AddressSanitizer: attempting free on address "
 108       "which was not malloc()-ed: %p in thread %s\n",
 109       addr_description.Address(), AsanThreadIdAndName(tid).c_str());
 110   Printf("%s", d.Default());
 111   CHECK_GT(free_stack->size, 0);
 112   scariness.Print();
 113   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
 114   stack.Print();
 115   addr_description.Print();
 116   ReportErrorSummary(scariness.GetDescription(), &stack);
 117 }
 118
 119 void ErrorAllocTypeMismatch::Print() {
 120   static const char *alloc_names[] = {"INVALID", "malloc", "operator new",
 121                                       "operator new []"};
 122   static const char *dealloc_names[] = {"INVALID", "free", "operator delete",
 123                                         "operator delete []"};
 124   CHECK_NE(alloc_type, dealloc_type);
 125   Decorator d;
 126   Printf("%s", d.Error());
 127   Report("ERROR: AddressSanitizer: %s (%s vs %s) on %p\n",
 128          scariness.GetDescription(), alloc_names[alloc_type],
 129          dealloc_names[dealloc_type], addr_description.Address());
 130   Printf("%s", d.Default());
 131   CHECK_GT(dealloc_stack->size, 0);
 132   scariness.Print();
 133   GET_STACK_TRACE_FATAL(dealloc_stack->trace[0], dealloc_stack->top_frame_bp);
 134   stack.Print();
 135   addr_description.Print();
 136   ReportErrorSummary(scariness.GetDescription(), &stack);
 137   Report(
 138       "HINT: if you don't care about these errors you may set "
 139       "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
 140 }
 141
 142 void ErrorMallocUsableSizeNotOwned::Print() {
 143   Decorator d;
 144   Printf("%s", d.Error());
 145   Report(
 146       "ERROR: AddressSanitizer: attempting to call malloc_usable_size() for "
 147       "pointer which is not owned: %p\n",
 148       addr_description.Address());
 149   Printf("%s", d.Default());
 150   stack->Print();
 151   addr_description.Print();
 152   ReportErrorSummary(scariness.GetDescription(), stack);
 153 }
 154
 155 void ErrorSanitizerGetAllocatedSizeNotOwned::Print() {
 156   Decorator d;
 157   Printf("%s", d.Error());
 158   Report(
 159       "ERROR: AddressSanitizer: attempting to call "
 160       "__sanitizer_get_allocated_size() for pointer which is not owned: %p\n",
 161       addr_description.Address());
 162   Printf("%s", d.Default());
 163   stack->Print();
 164   addr_description.Print();
 165   ReportErrorSummary(scariness.GetDescription(), stack);
 166 }
 167
 168 void ErrorCallocOverflow::Print() {
 169   Decorator d;
 170   Printf("%s", d.Error());
 171   Report(
 172       "ERROR: AddressSanitizer: calloc parameters overflow: count * size "
 173       "(%zd * %zd) cannot be represented in type size_t (thread %s)\n",
 174       count, size, AsanThreadIdAndName(tid).c_str());
 175   Printf("%s", d.Default());
 176   stack->Print();
 177   PrintHintAllocatorCannotReturnNull();
 178   ReportErrorSummary(scariness.GetDescription(), stack);
 179 }
 180
 181 void ErrorReallocArrayOverflow::Print() {
 182   Decorator d;
 183   Printf("%s", d.Error());
 184   Report(
 185       "ERROR: AddressSanitizer: reallocarray parameters overflow: count * size "
 186       "(%zd * %zd) cannot be represented in type size_t (thread %s)\n",
 187       count, size, AsanThreadIdAndName(tid).c_str());
 188   Printf("%s", d.Default());
 189   stack->Print();
 190   PrintHintAllocatorCannotReturnNull();
 191   ReportErrorSummary(scariness.GetDescription(), stack);
 192 }
 193
 194 void ErrorPvallocOverflow::Print() {
 195   Decorator d;
 196   Printf("%s", d.Error());
 197   Report(
 198       "ERROR: AddressSanitizer: pvalloc parameters overflow: size 0x%zx "
 199       "rounded up to system page size 0x%zx cannot be represented in type "
 200       "size_t (thread %s)\n",
 201       size, GetPageSizeCached(), AsanThreadIdAndName(tid).c_str());
 202   Printf("%s", d.Default());
 203   stack->Print();
 204   PrintHintAllocatorCannotReturnNull();
 205   ReportErrorSummary(scariness.GetDescription(), stack);
 206 }
 207
 208 void ErrorInvalidAllocationAlignment::Print() {
 209   Decorator d;
 210   Printf("%s", d.Error());
 211   Report(
 212       "ERROR: AddressSanitizer: invalid allocation alignment: %zd, "
 213       "alignment must be a power of two (thread %s)\n",
 214       alignment, AsanThreadIdAndName(tid).c_str());
 215   Printf("%s", d.Default());
 216   stack->Print();
 217   PrintHintAllocatorCannotReturnNull();
 218   ReportErrorSummary(scariness.GetDescription(), stack);
 219 }
 220
 221 void ErrorInvalidAlignedAllocAlignment::Print() {
 222   Decorator d;
 223   Printf("%s", d.Error());
 224 #if SANITIZER_POSIX
 225   Report("ERROR: AddressSanitizer: invalid alignment requested in "
 226          "aligned_alloc: %zd, alignment must be a power of two and the "
 227          "requested size 0x%zx must be a multiple of alignment "
 228          "(thread %s)\n", alignment, size, AsanThreadIdAndName(tid).c_str());
 229 #else
 230   Report("ERROR: AddressSanitizer: invalid alignment requested in "
 231          "aligned_alloc: %zd, the requested size 0x%zx must be a multiple of "
 232          "alignment (thread %s)\n", alignment, size,
 233          AsanThreadIdAndName(tid).c_str());
 234 #endif
 235   Printf("%s", d.Default());
 236   stack->Print();
 237   PrintHintAllocatorCannotReturnNull();
 238   ReportErrorSummary(scariness.GetDescription(), stack);
 239 }
 240
 241 void ErrorInvalidPosixMemalignAlignment::Print() {
 242   Decorator d;
 243   Printf("%s", d.Error());
 244   Report(
 245       "ERROR: AddressSanitizer: invalid alignment requested in posix_memalign: "
 246       "%zd, alignment must be a power of two and a multiple of sizeof(void*) "
 247       "== %zd (thread %s)\n",
 248       alignment, sizeof(void *), AsanThreadIdAndName(tid).c_str());
 249   Printf("%s", d.Default());
 250   stack->Print();
 251   PrintHintAllocatorCannotReturnNull();
 252   ReportErrorSummary(scariness.GetDescription(), stack);
 253 }
 254
 255 void ErrorAllocationSizeTooBig::Print() {
 256   Decorator d;
 257   Printf("%s", d.Error());
 258   Report(
 259       "ERROR: AddressSanitizer: requested allocation size 0x%zx (0x%zx after "
 260       "adjustments for alignment, red zones etc.) exceeds maximum supported "
 261       "size of 0x%zx (thread %s)\n",
 262       user_size, total_size, max_size, AsanThreadIdAndName(tid).c_str());
 263   Printf("%s", d.Default());
 264   stack->Print();
 265   PrintHintAllocatorCannotReturnNull();
 266   ReportErrorSummary(scariness.GetDescription(), stack);
 267 }
 268
 269 void ErrorRssLimitExceeded::Print() {
 270   Decorator d;
 271   Printf("%s", d.Error());
 272   Report(
 273       "ERROR: AddressSanitizer: specified RSS limit exceeded, currently set to "
 274       "soft_rss_limit_mb=%zd\n", common_flags()->soft_rss_limit_mb);
 275   Printf("%s", d.Default());
 276   stack->Print();
 277   PrintHintAllocatorCannotReturnNull();
 278   ReportErrorSummary(scariness.GetDescription(), stack);
 279 }
 280
 281 void ErrorOutOfMemory::Print() {
 282   Decorator d;
 283   Printf("%s", d.Error());
 284   Report(
 285       "ERROR: AddressSanitizer: allocator is out of memory trying to allocate "
 286       "0x%zx bytes\n", requested_size);
 287   Printf("%s", d.Default());
 288   stack->Print();
 289   PrintHintAllocatorCannotReturnNull();
 290   ReportErrorSummary(scariness.GetDescription(), stack);
 291 }
 292
 293 void ErrorStringFunctionMemoryRangesOverlap::Print() {
 294   Decorator d;
 295   char bug_type[100];
 296   internal_snprintf(bug_type, sizeof(bug_type), "%s-param-overlap", function);
 297   Printf("%s", d.Error());
 298   Report(
 299       "ERROR: AddressSanitizer: %s: memory ranges [%p,%p) and [%p, %p) "
 300       "overlap\n",
 301       bug_type, addr1_description.Address(),
 302       addr1_description.Address() + length1, addr2_description.Address(),
 303       addr2_description.Address() + length2);
 304   Printf("%s", d.Default());
 305   scariness.Print();
 306   stack->Print();
 307   addr1_description.Print();
 308   addr2_description.Print();
 309   ReportErrorSummary(bug_type, stack);
 310 }
 311
 312 void ErrorStringFunctionSizeOverflow::Print() {
 313   Decorator d;
 314   Printf("%s", d.Error());
 315   Report("ERROR: AddressSanitizer: %s: (size=%zd)\n",
 316          scariness.GetDescription(), size);
 317   Printf("%s", d.Default());
 318   scariness.Print();
 319   stack->Print();
 320   addr_description.Print();
 321   ReportErrorSummary(scariness.GetDescription(), stack);
 322 }
 323
 324 void ErrorBadParamsToAnnotateContiguousContainer::Print() {
 325   Report(
 326       "ERROR: AddressSanitizer: bad parameters to "
 327       "__sanitizer_annotate_contiguous_container:\n"
 328       "      beg     : %p\n"
 329       "      end     : %p\n"
 330       "      old_mid : %p\n"
 331       "      new_mid : %p\n",
 332       beg, end, old_mid, new_mid);
 333   uptr granularity = SHADOW_GRANULARITY;
 334   if (!IsAligned(beg, granularity))
 335     Report("ERROR: beg is not aligned by %d\n", granularity);
 336   stack->Print();
 337   ReportErrorSummary(scariness.GetDescription(), stack);
 338 }
 339
 340 void ErrorODRViolation::Print() {
 341   Decorator d;
 342   Printf("%s", d.Error());
 343   Report("ERROR: AddressSanitizer: %s (%p):\n", scariness.GetDescription(),
 344          global1.beg);
 345   Printf("%s", d.Default());
 346   InternalScopedString g1_loc;
 347   InternalScopedString g2_loc;
 348   PrintGlobalLocation(&g1_loc, global1);
 349   PrintGlobalLocation(&g2_loc, global2);
 350   Printf("  [1] size=%zd '%s' %s\n", global1.size,
 351          MaybeDemangleGlobalName(global1.name), g1_loc.data());
 352   Printf("  [2] size=%zd '%s' %s\n", global2.size,
 353          MaybeDemangleGlobalName(global2.name), g2_loc.data());
 354   if (stack_id1 && stack_id2) {
 355     Printf("These globals were registered at these points:\n");
 356     Printf("  [1]:\n");
 357     StackDepotGet(stack_id1).Print();
 358     Printf("  [2]:\n");
 359     StackDepotGet(stack_id2).Print();
 360   }
 361   Report(
 362       "HINT: if you don't care about these errors you may set "
 363       "ASAN_OPTIONS=detect_odr_violation=0\n");
 364   InternalScopedString error_msg;
 365   error_msg.append("%s: global '%s' at %s", scariness.GetDescription(),
 366                    MaybeDemangleGlobalName(global1.name), g1_loc.data());
 367   ReportErrorSummary(error_msg.data());
 368 }
 369
 370 void ErrorInvalidPointerPair::Print() {
 371   Decorator d;
 372   Printf("%s", d.Error());
 373   Report("ERROR: AddressSanitizer: %s: %p %p\n", scariness.GetDescription(),
 374          addr1_description.Address(), addr2_description.Address());
 375   Printf("%s", d.Default());
 376   GET_STACK_TRACE_FATAL(pc, bp);
 377   stack.Print();
 378   addr1_description.Print();
 379   addr2_description.Print();
 380   ReportErrorSummary(scariness.GetDescription(), &stack);
 381 }
 382
 383 static bool AdjacentShadowValuesAreFullyPoisoned(u8 *s) {
 384   return s[-1] > 127 && s[1] > 127;
 385 }
 386
 387 ErrorGeneric::ErrorGeneric(u32 tid, uptr pc_, uptr bp_, uptr sp_, uptr addr,
 388                            bool is_write_, uptr access_size_)
 389     : ErrorBase(tid),
 390       addr_description(addr, access_size_, /*shouldLockThreadRegistry=*/false),
 391       pc(pc_),
 392       bp(bp_),
 393       sp(sp_),
 394       access_size(access_size_),
 395       is_write(is_write_),
 396       shadow_val(0) {
 397   scariness.Clear();
 398   if (access_size) {
 399     if (access_size <= 9) {
 400       char desr[] = "?-byte";
 401       desr[0] = '0' + access_size;
 402       scariness.Scare(access_size + access_size / 2, desr);
 403     } else if (access_size >= 10) {
 404       scariness.Scare(15, "multi-byte");
 405     }
 406     is_write ? scariness.Scare(20, "write") : scariness.Scare(1, "read");
 407
 408     // Determine the error type.
 409     bug_descr = "unknown-crash";
 410     if (AddrIsInMem(addr)) {
 411       u8 *shadow_addr = (u8 *)MemToShadow(addr);
 412       // If we are accessing 16 bytes, look at the second shadow byte.
 413       if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY) shadow_addr++;
 414       // If we are in the partial right redzone, look at the next shadow byte.
 415       if (*shadow_addr > 0 && *shadow_addr < 128) shadow_addr++;
 416       bool far_from_bounds = false;
 417       shadow_val = *shadow_addr;
 418       int bug_type_score = 0;
 419       // For use-after-frees reads are almost as bad as writes.
 420       int read_after_free_bonus = 0;
 421       switch (shadow_val) {
 422         case kAsanHeapLeftRedzoneMagic:
 423         case kAsanArrayCookieMagic:
 424           bug_descr = "heap-buffer-overflow";
 425           bug_type_score = 10;
 426           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 427           break;
 428         case kAsanHeapFreeMagic:
 429           bug_descr = "heap-use-after-free";
 430           bug_type_score = 20;
 431           if (!is_write) read_after_free_bonus = 18;
 432           break;
 433         case kAsanStackLeftRedzoneMagic:
 434           bug_descr = "stack-buffer-underflow";
 435           bug_type_score = 25;
 436           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 437           break;
 438         case kAsanInitializationOrderMagic:
 439           bug_descr = "initialization-order-fiasco";
 440           bug_type_score = 1;
 441           break;
 442         case kAsanStackMidRedzoneMagic:
 443         case kAsanStackRightRedzoneMagic:
 444           bug_descr = "stack-buffer-overflow";
 445           bug_type_score = 25;
 446           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 447           break;
 448         case kAsanStackAfterReturnMagic:
 449           bug_descr = "stack-use-after-return";
 450           bug_type_score = 30;
 451           if (!is_write) read_after_free_bonus = 18;
 452           break;
 453         case kAsanUserPoisonedMemoryMagic:
 454           bug_descr = "use-after-poison";
 455           bug_type_score = 20;
 456           break;
 457         case kAsanContiguousContainerOOBMagic:
 458           bug_descr = "container-overflow";
 459           bug_type_score = 10;
 460           break;
 461         case kAsanStackUseAfterScopeMagic:
 462           bug_descr = "stack-use-after-scope";
 463           bug_type_score = 10;
 464           break;
 465         case kAsanGlobalRedzoneMagic:
 466           bug_descr = "global-buffer-overflow";
 467           bug_type_score = 10;
 468           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 469           break;
 470         case kAsanIntraObjectRedzone:
 471           bug_descr = "intra-object-overflow";
 472           bug_type_score = 10;
 473           break;
 474         case kAsanAllocaLeftMagic:
 475         case kAsanAllocaRightMagic:
 476           bug_descr = "dynamic-stack-buffer-overflow";
 477           bug_type_score = 25;
 478           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 479           break;
 480       }
 481       scariness.Scare(bug_type_score + read_after_free_bonus, bug_descr);
 482       if (far_from_bounds) scariness.Scare(10, "far-from-bounds");
 483     }
 484   }
 485 }
 486
 487 static void PrintContainerOverflowHint() {
 488   Printf("HINT: if you don't care about these errors you may set "
 489          "ASAN_OPTIONS=detect_container_overflow=0.\n"
 490          "If you suspect a false positive see also: "
 491          "https://github.com/google/sanitizers/wiki/"
 492          "AddressSanitizerContainerOverflow.\n");
 493 }
 494
 495 static void PrintShadowByte(InternalScopedString *str, const char *before,
 496     u8 byte, const char *after = "\n") {
 497   PrintMemoryByte(str, before, byte, /*in_shadow*/true, after);
 498 }
 499
 500 static void PrintLegend(InternalScopedString *str) {
 501   str->append(
 502       "Shadow byte legend (one shadow byte represents %d "
 503       "application bytes):\n",
 504       (int)SHADOW_GRANULARITY);
 505   PrintShadowByte(str, "  Addressable:           ", 0);
 506   str->append("  Partially addressable: ");
 507   for (u8 i = 1; i < SHADOW_GRANULARITY; i++) PrintShadowByte(str, "", i, " ");
 508   str->append("\n");
 509   PrintShadowByte(str, "  Heap left redzone:       ",
 510                   kAsanHeapLeftRedzoneMagic);
 511   PrintShadowByte(str, "  Freed heap region:       ", kAsanHeapFreeMagic);
 512   PrintShadowByte(str, "  Stack left redzone:      ",
 513                   kAsanStackLeftRedzoneMagic);
 514   PrintShadowByte(str, "  Stack mid redzone:       ",
 515                   kAsanStackMidRedzoneMagic);
 516   PrintShadowByte(str, "  Stack right redzone:     ",
 517                   kAsanStackRightRedzoneMagic);
 518   PrintShadowByte(str, "  Stack after return:      ",
 519                   kAsanStackAfterReturnMagic);
 520   PrintShadowByte(str, "  Stack use after scope:   ",
 521                   kAsanStackUseAfterScopeMagic);
 522   PrintShadowByte(str, "  Global redzone:          ", kAsanGlobalRedzoneMagic);
 523   PrintShadowByte(str, "  Global init order:       ",
 524                   kAsanInitializationOrderMagic);
 525   PrintShadowByte(str, "  Poisoned by user:        ",
 526                   kAsanUserPoisonedMemoryMagic);
 527   PrintShadowByte(str, "  Container overflow:      ",
 528                   kAsanContiguousContainerOOBMagic);
 529   PrintShadowByte(str, "  Array cookie:            ",
 530                   kAsanArrayCookieMagic);
 531   PrintShadowByte(str, "  Intra object redzone:    ",
 532                   kAsanIntraObjectRedzone);
 533   PrintShadowByte(str, "  ASan internal:           ", kAsanInternalHeapMagic);
 534   PrintShadowByte(str, "  Left alloca redzone:     ", kAsanAllocaLeftMagic);
 535   PrintShadowByte(str, "  Right alloca redzone:    ", kAsanAllocaRightMagic);
 536 }
 537
 538 static void PrintShadowBytes(InternalScopedString *str, const char *before,
 539                              u8 *bytes, u8 *guilty, uptr n) {
 540   Decorator d;
 541   if (before) str->append("%s%p:", before, bytes);
 542   for (uptr i = 0; i < n; i++) {
 543     u8 *p = bytes + i;
 544     const char *before =
 545         p == guilty ? "[" : (p - 1 == guilty && i != 0) ? "" : " ";
 546     const char *after = p == guilty ? "]" : "";
 547     PrintShadowByte(str, before, *p, after);
 548   }
 549   str->append("\n");
 550 }
 551
 552 static void PrintShadowMemoryForAddress(uptr addr) {
 553   if (!AddrIsInMem(addr)) return;
 554   uptr shadow_addr = MemToShadow(addr);
 555   const uptr n_bytes_per_row = 16;
 556   uptr aligned_shadow = shadow_addr & ~(n_bytes_per_row - 1);
 557   InternalScopedString str;
 558   str.append("Shadow bytes around the buggy address:\n");
 559   for (int i = -5; i <= 5; i++) {
 560     uptr row_shadow_addr = aligned_shadow + i * n_bytes_per_row;
 561     // Skip rows that would be outside the shadow range. This can happen when
 562     // the user address is near the bottom, top, or shadow gap of the address
 563     // space.
 564     if (!AddrIsInShadow(row_shadow_addr)) continue;
 565     const char *prefix = (i == 0) ? "=>" : "  ";
 566     PrintShadowBytes(&str, prefix, (u8 *)row_shadow_addr, (u8 *)shadow_addr,
 567                      n_bytes_per_row);
 568   }
 569   if (flags()->print_legend) PrintLegend(&str);
 570   Printf("%s", str.data());
 571 }
 572
 573 void ErrorGeneric::Print() {
 574   Decorator d;
 575   Printf("%s", d.Error());
 576   uptr addr = addr_description.Address();
 577   Report("ERROR: AddressSanitizer: %s on address %p at pc %p bp %p sp %p\n",
 578          bug_descr, (void *)addr, pc, bp, sp);
 579   Printf("%s", d.Default());
 580
 581   Printf("%s%s of size %zu at %p thread %s%s\n", d.Access(),
 582          access_size ? (is_write ? "WRITE" : "READ") : "ACCESS", access_size,
 583          (void *)addr, AsanThreadIdAndName(tid).c_str(), d.Default());
 584
 585   scariness.Print();
 586   GET_STACK_TRACE_FATAL(pc, bp);
 587   stack.Print();
 588
 589   // Pass bug_descr because we have a special case for
 590   // initialization-order-fiasco
 591   addr_description.Print(bug_descr);
 592   if (shadow_val == kAsanContiguousContainerOOBMagic)
 593     PrintContainerOverflowHint();
 594   ReportErrorSummary(bug_descr, &stack);
 595   PrintShadowMemoryForAddress(addr);
 596 }
 597
 598 }  // namespace __asan