compiler-rt/lib/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("ERROR: AddressSanitizer: attempting %s on %p in thread %s:\n",
  50          scariness.GetDescription(), (void *)addr_description.addr,
  51          AsanThreadIdAndName(tid).c_str());
  52   Printf("%s", d.Default());
  53   scariness.Print();
  54   GET_STACK_TRACE_FATAL(second_free_stack->trace[0],
  55                         second_free_stack->top_frame_bp);
  56   stack.Print();
  57   addr_description.Print();
  58   ReportErrorSummary(scariness.GetDescription(), &stack);
  59 }
  60
  61 void ErrorNewDeleteTypeMismatch::Print() {
  62   Decorator d;
  63   Printf("%s", d.Error());
  64   Report("ERROR: AddressSanitizer: %s on %p in thread %s:\n",
  65          scariness.GetDescription(), (void *)addr_description.addr,
  66          AsanThreadIdAndName(tid).c_str());
  67   Printf("%s  object passed to delete has wrong type:\n", d.Default());
  68   if (delete_size != 0) {
  69     Printf(
  70         "  size of the allocated type:   %zd bytes;\n"
  71         "  size of the deallocated type: %zd bytes.\n",
  72         addr_description.chunk_access.chunk_size, delete_size);
  73   }
  74   const uptr user_alignment =
  75       addr_description.chunk_access.user_requested_alignment;
  76   if (delete_alignment != user_alignment) {
  77     char user_alignment_str[32];
  78     char delete_alignment_str[32];
  79     internal_snprintf(user_alignment_str, sizeof(user_alignment_str),
  80                       "%zd bytes", user_alignment);
  81     internal_snprintf(delete_alignment_str, sizeof(delete_alignment_str),
  82                       "%zd bytes", delete_alignment);
  83     static const char *kDefaultAlignment = "default-aligned";
  84     Printf(
  85         "  alignment of the allocated type:   %s;\n"
  86         "  alignment of the deallocated type: %s.\n",
  87         user_alignment > 0 ? user_alignment_str : kDefaultAlignment,
  88         delete_alignment > 0 ? delete_alignment_str : kDefaultAlignment);
  89   }
  90   CHECK_GT(free_stack->size, 0);
  91   scariness.Print();
  92   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
  93   stack.Print();
  94   addr_description.Print();
  95   ReportErrorSummary(scariness.GetDescription(), &stack);
  96   Report(
  97       "HINT: if you don't care about these errors you may set "
  98       "ASAN_OPTIONS=new_delete_type_mismatch=0\n");
  99 }
 100
 101 void ErrorFreeNotMalloced::Print() {
 102   Decorator d;
 103   Printf("%s", d.Error());
 104   Report(
 105       "ERROR: AddressSanitizer: attempting free on address "
 106       "which was not malloc()-ed: %p in thread %s\n",
 107       (void *)addr_description.Address(), AsanThreadIdAndName(tid).c_str());
 108   Printf("%s", d.Default());
 109   CHECK_GT(free_stack->size, 0);
 110   scariness.Print();
 111   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
 112   stack.Print();
 113   addr_description.Print();
 114   ReportErrorSummary(scariness.GetDescription(), &stack);
 115 }
 116
 117 void ErrorAllocTypeMismatch::Print() {
 118   static const char *alloc_names[] = {"INVALID", "malloc", "operator new",
 119                                       "operator new []"};
 120   static const char *dealloc_names[] = {"INVALID", "free", "operator delete",
 121                                         "operator delete []"};
 122   CHECK_NE(alloc_type, dealloc_type);
 123   Decorator d;
 124   Printf("%s", d.Error());
 125   Report("ERROR: AddressSanitizer: %s (%s vs %s) on %p\n",
 126          scariness.GetDescription(), alloc_names[alloc_type],
 127          dealloc_names[dealloc_type], (void *)addr_description.Address());
 128   Printf("%s", d.Default());
 129   CHECK_GT(dealloc_stack->size, 0);
 130   scariness.Print();
 131   GET_STACK_TRACE_FATAL(dealloc_stack->trace[0], dealloc_stack->top_frame_bp);
 132   stack.Print();
 133   addr_description.Print();
 134   ReportErrorSummary(scariness.GetDescription(), &stack);
 135   Report(
 136       "HINT: if you don't care about these errors you may set "
 137       "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
 138 }
 139
 140 void ErrorMallocUsableSizeNotOwned::Print() {
 141   Decorator d;
 142   Printf("%s", d.Error());
 143   Report(
 144       "ERROR: AddressSanitizer: attempting to call malloc_usable_size() for "
 145       "pointer which is not owned: %p\n",
 146       (void *)addr_description.Address());
 147   Printf("%s", d.Default());
 148   stack->Print();
 149   addr_description.Print();
 150   ReportErrorSummary(scariness.GetDescription(), stack);
 151 }
 152
 153 void ErrorSanitizerGetAllocatedSizeNotOwned::Print() {
 154   Decorator d;
 155   Printf("%s", d.Error());
 156   Report(
 157       "ERROR: AddressSanitizer: attempting to call "
 158       "__sanitizer_get_allocated_size() for pointer which is not owned: %p\n",
 159       (void *)addr_description.Address());
 160   Printf("%s", d.Default());
 161   stack->Print();
 162   addr_description.Print();
 163   ReportErrorSummary(scariness.GetDescription(), stack);
 164 }
 165
 166 void ErrorCallocOverflow::Print() {
 167   Decorator d;
 168   Printf("%s", d.Error());
 169   Report(
 170       "ERROR: AddressSanitizer: calloc parameters overflow: count * size "
 171       "(%zd * %zd) cannot be represented in type size_t (thread %s)\n",
 172       count, size, AsanThreadIdAndName(tid).c_str());
 173   Printf("%s", d.Default());
 174   stack->Print();
 175   PrintHintAllocatorCannotReturnNull();
 176   ReportErrorSummary(scariness.GetDescription(), stack);
 177 }
 178
 179 void ErrorReallocArrayOverflow::Print() {
 180   Decorator d;
 181   Printf("%s", d.Error());
 182   Report(
 183       "ERROR: AddressSanitizer: reallocarray parameters overflow: count * size "
 184       "(%zd * %zd) cannot be represented in type size_t (thread %s)\n",
 185       count, size, AsanThreadIdAndName(tid).c_str());
 186   Printf("%s", d.Default());
 187   stack->Print();
 188   PrintHintAllocatorCannotReturnNull();
 189   ReportErrorSummary(scariness.GetDescription(), stack);
 190 }
 191
 192 void ErrorPvallocOverflow::Print() {
 193   Decorator d;
 194   Printf("%s", d.Error());
 195   Report(
 196       "ERROR: AddressSanitizer: pvalloc parameters overflow: size 0x%zx "
 197       "rounded up to system page size 0x%zx cannot be represented in type "
 198       "size_t (thread %s)\n",
 199       size, GetPageSizeCached(), AsanThreadIdAndName(tid).c_str());
 200   Printf("%s", d.Default());
 201   stack->Print();
 202   PrintHintAllocatorCannotReturnNull();
 203   ReportErrorSummary(scariness.GetDescription(), stack);
 204 }
 205
 206 void ErrorInvalidAllocationAlignment::Print() {
 207   Decorator d;
 208   Printf("%s", d.Error());
 209   Report(
 210       "ERROR: AddressSanitizer: invalid allocation alignment: %zd, "
 211       "alignment must be a power of two (thread %s)\n",
 212       alignment, AsanThreadIdAndName(tid).c_str());
 213   Printf("%s", d.Default());
 214   stack->Print();
 215   PrintHintAllocatorCannotReturnNull();
 216   ReportErrorSummary(scariness.GetDescription(), stack);
 217 }
 218
 219 void ErrorInvalidAlignedAllocAlignment::Print() {
 220   Decorator d;
 221   Printf("%s", d.Error());
 222 #if SANITIZER_POSIX
 223   Report("ERROR: AddressSanitizer: invalid alignment requested in "
 224          "aligned_alloc: %zd, alignment must be a power of two and the "
 225          "requested size 0x%zx must be a multiple of alignment "
 226          "(thread %s)\n", alignment, size, AsanThreadIdAndName(tid).c_str());
 227 #else
 228   Report("ERROR: AddressSanitizer: invalid alignment requested in "
 229          "aligned_alloc: %zd, the requested size 0x%zx must be a multiple of "
 230          "alignment (thread %s)\n", alignment, size,
 231          AsanThreadIdAndName(tid).c_str());
 232 #endif
 233   Printf("%s", d.Default());
 234   stack->Print();
 235   PrintHintAllocatorCannotReturnNull();
 236   ReportErrorSummary(scariness.GetDescription(), stack);
 237 }
 238
 239 void ErrorInvalidPosixMemalignAlignment::Print() {
 240   Decorator d;
 241   Printf("%s", d.Error());
 242   Report(
 243       "ERROR: AddressSanitizer: invalid alignment requested in posix_memalign: "
 244       "%zd, alignment must be a power of two and a multiple of sizeof(void*) "
 245       "== %zd (thread %s)\n",
 246       alignment, sizeof(void *), AsanThreadIdAndName(tid).c_str());
 247   Printf("%s", d.Default());
 248   stack->Print();
 249   PrintHintAllocatorCannotReturnNull();
 250   ReportErrorSummary(scariness.GetDescription(), stack);
 251 }
 252
 253 void ErrorAllocationSizeTooBig::Print() {
 254   Decorator d;
 255   Printf("%s", d.Error());
 256   Report(
 257       "ERROR: AddressSanitizer: requested allocation size 0x%zx (0x%zx after "
 258       "adjustments for alignment, red zones etc.) exceeds maximum supported "
 259       "size of 0x%zx (thread %s)\n",
 260       user_size, total_size, max_size, AsanThreadIdAndName(tid).c_str());
 261   Printf("%s", d.Default());
 262   stack->Print();
 263   PrintHintAllocatorCannotReturnNull();
 264   ReportErrorSummary(scariness.GetDescription(), stack);
 265 }
 266
 267 void ErrorRssLimitExceeded::Print() {
 268   Decorator d;
 269   Printf("%s", d.Error());
 270   Report(
 271       "ERROR: AddressSanitizer: specified RSS limit exceeded, currently set to "
 272       "soft_rss_limit_mb=%zd\n", common_flags()->soft_rss_limit_mb);
 273   Printf("%s", d.Default());
 274   stack->Print();
 275   PrintHintAllocatorCannotReturnNull();
 276   ReportErrorSummary(scariness.GetDescription(), stack);
 277 }
 278
 279 void ErrorOutOfMemory::Print() {
 280   Decorator d;
 281   Printf("%s", d.Error());
 282   Report(
 283       "ERROR: AddressSanitizer: allocator is out of memory trying to allocate "
 284       "0x%zx bytes\n", requested_size);
 285   Printf("%s", d.Default());
 286   stack->Print();
 287   PrintHintAllocatorCannotReturnNull();
 288   ReportErrorSummary(scariness.GetDescription(), stack);
 289 }
 290
 291 void ErrorStringFunctionMemoryRangesOverlap::Print() {
 292   Decorator d;
 293   char bug_type[100];
 294   internal_snprintf(bug_type, sizeof(bug_type), "%s-param-overlap", function);
 295   Printf("%s", d.Error());
 296   Report(
 297       "ERROR: AddressSanitizer: %s: memory ranges [%p,%p) and [%p, %p) "
 298       "overlap\n",
 299       bug_type, (void *)addr1_description.Address(),
 300       (void *)(addr1_description.Address() + length1),
 301       (void *)addr2_description.Address(),
 302       (void *)(addr2_description.Address() + length2));
 303   Printf("%s", d.Default());
 304   scariness.Print();
 305   stack->Print();
 306   addr1_description.Print();
 307   addr2_description.Print();
 308   ReportErrorSummary(bug_type, stack);
 309 }
 310
 311 void ErrorStringFunctionSizeOverflow::Print() {
 312   Decorator d;
 313   Printf("%s", d.Error());
 314   Report("ERROR: AddressSanitizer: %s: (size=%zd)\n",
 315          scariness.GetDescription(), size);
 316   Printf("%s", d.Default());
 317   scariness.Print();
 318   stack->Print();
 319   addr_description.Print();
 320   ReportErrorSummary(scariness.GetDescription(), stack);
 321 }
 322
 323 void ErrorBadParamsToAnnotateContiguousContainer::Print() {
 324   Report(
 325       "ERROR: AddressSanitizer: bad parameters to "
 326       "__sanitizer_annotate_contiguous_container:\n"
 327       "      beg     : %p\n"
 328       "      end     : %p\n"
 329       "      old_mid : %p\n"
 330       "      new_mid : %p\n",
 331       (void *)beg, (void *)end, (void *)old_mid, (void *)new_mid);
 332   uptr granularity = ASAN_SHADOW_GRANULARITY;
 333   if (!IsAligned(beg, granularity))
 334     Report("ERROR: beg is not aligned by %zu\n", granularity);
 335   stack->Print();
 336   ReportErrorSummary(scariness.GetDescription(), stack);
 337 }
 338
 339 void ErrorODRViolation::Print() {
 340   Decorator d;
 341   Printf("%s", d.Error());
 342   Report("ERROR: AddressSanitizer: %s (%p):\n", scariness.GetDescription(),
 343          (void *)global1.beg);
 344   Printf("%s", d.Default());
 345   InternalScopedString g1_loc;
 346   InternalScopedString g2_loc;
 347   PrintGlobalLocation(&g1_loc, global1);
 348   PrintGlobalLocation(&g2_loc, global2);
 349   Printf("  [1] size=%zd '%s' %s\n", global1.size,
 350          MaybeDemangleGlobalName(global1.name), g1_loc.data());
 351   Printf("  [2] size=%zd '%s' %s\n", global2.size,
 352          MaybeDemangleGlobalName(global2.name), g2_loc.data());
 353   if (stack_id1 && stack_id2) {
 354     Printf("These globals were registered at these points:\n");
 355     Printf("  [1]:\n");
 356     StackDepotGet(stack_id1).Print();
 357     Printf("  [2]:\n");
 358     StackDepotGet(stack_id2).Print();
 359   }
 360   Report(
 361       "HINT: if you don't care about these errors you may set "
 362       "ASAN_OPTIONS=detect_odr_violation=0\n");
 363   InternalScopedString error_msg;
 364   error_msg.append("%s: global '%s' at %s", scariness.GetDescription(),
 365                    MaybeDemangleGlobalName(global1.name), g1_loc.data());
 366   ReportErrorSummary(error_msg.data());
 367 }
 368
 369 void ErrorInvalidPointerPair::Print() {
 370   Decorator d;
 371   Printf("%s", d.Error());
 372   Report("ERROR: AddressSanitizer: %s: %p %p\n", scariness.GetDescription(),
 373          (void *)addr1_description.Address(),
 374          (void *)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 > ASAN_SHADOW_GRANULARITY)
 414         shadow_addr++;
 415       // If we are in the partial right redzone, look at the next shadow byte.
 416       if (*shadow_addr > 0 && *shadow_addr < 128) shadow_addr++;
 417       bool far_from_bounds = false;
 418       shadow_val = *shadow_addr;
 419       int bug_type_score = 0;
 420       // For use-after-frees reads are almost as bad as writes.
 421       int read_after_free_bonus = 0;
 422       switch (shadow_val) {
 423         case kAsanHeapLeftRedzoneMagic:
 424         case kAsanArrayCookieMagic:
 425           bug_descr = "heap-buffer-overflow";
 426           bug_type_score = 10;
 427           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 428           break;
 429         case kAsanHeapFreeMagic:
 430           bug_descr = "heap-use-after-free";
 431           bug_type_score = 20;
 432           if (!is_write) read_after_free_bonus = 18;
 433           break;
 434         case kAsanStackLeftRedzoneMagic:
 435           bug_descr = "stack-buffer-underflow";
 436           bug_type_score = 25;
 437           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 438           break;
 439         case kAsanInitializationOrderMagic:
 440           bug_descr = "initialization-order-fiasco";
 441           bug_type_score = 1;
 442           break;
 443         case kAsanStackMidRedzoneMagic:
 444         case kAsanStackRightRedzoneMagic:
 445           bug_descr = "stack-buffer-overflow";
 446           bug_type_score = 25;
 447           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 448           break;
 449         case kAsanStackAfterReturnMagic:
 450           bug_descr = "stack-use-after-return";
 451           bug_type_score = 30;
 452           if (!is_write) read_after_free_bonus = 18;
 453           break;
 454         case kAsanUserPoisonedMemoryMagic:
 455           bug_descr = "use-after-poison";
 456           bug_type_score = 20;
 457           break;
 458         case kAsanContiguousContainerOOBMagic:
 459           bug_descr = "container-overflow";
 460           bug_type_score = 10;
 461           break;
 462         case kAsanStackUseAfterScopeMagic:
 463           bug_descr = "stack-use-after-scope";
 464           bug_type_score = 10;
 465           break;
 466         case kAsanGlobalRedzoneMagic:
 467           bug_descr = "global-buffer-overflow";
 468           bug_type_score = 10;
 469           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 470           break;
 471         case kAsanIntraObjectRedzone:
 472           bug_descr = "intra-object-overflow";
 473           bug_type_score = 10;
 474           break;
 475         case kAsanAllocaLeftMagic:
 476         case kAsanAllocaRightMagic:
 477           bug_descr = "dynamic-stack-buffer-overflow";
 478           bug_type_score = 25;
 479           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 480           break;
 481       }
 482       scariness.Scare(bug_type_score + read_after_free_bonus, bug_descr);
 483       if (far_from_bounds) scariness.Scare(10, "far-from-bounds");
 484     }
 485   }
 486 }
 487
 488 static void PrintContainerOverflowHint() {
 489   Printf("HINT: if you don't care about these errors you may set "
 490          "ASAN_OPTIONS=detect_container_overflow=0.\n"
 491          "If you suspect a false positive see also: "
 492          "https://github.com/google/sanitizers/wiki/"
 493          "AddressSanitizerContainerOverflow.\n");
 494 }
 495
 496 static void PrintShadowByte(InternalScopedString *str, const char *before,
 497     u8 byte, const char *after = "\n") {
 498   PrintMemoryByte(str, before, byte, /*in_shadow*/true, after);
 499 }
 500
 501 static void PrintLegend(InternalScopedString *str) {
 502   str->append(
 503       "Shadow byte legend (one shadow byte represents %d "
 504       "application bytes):\n",
 505       (int)ASAN_SHADOW_GRANULARITY);
 506   PrintShadowByte(str, "  Addressable:           ", 0);
 507   str->append("  Partially addressable: ");
 508   for (u8 i = 1; i < ASAN_SHADOW_GRANULARITY; i++)
 509     PrintShadowByte(str, "", i, " ");
 510   str->append("\n");
 511   PrintShadowByte(str, "  Heap left redzone:       ",
 512                   kAsanHeapLeftRedzoneMagic);
 513   PrintShadowByte(str, "  Freed heap region:       ", kAsanHeapFreeMagic);
 514   PrintShadowByte(str, "  Stack left redzone:      ",
 515                   kAsanStackLeftRedzoneMagic);
 516   PrintShadowByte(str, "  Stack mid redzone:       ",
 517                   kAsanStackMidRedzoneMagic);
 518   PrintShadowByte(str, "  Stack right redzone:     ",
 519                   kAsanStackRightRedzoneMagic);
 520   PrintShadowByte(str, "  Stack after return:      ",
 521                   kAsanStackAfterReturnMagic);
 522   PrintShadowByte(str, "  Stack use after scope:   ",
 523                   kAsanStackUseAfterScopeMagic);
 524   PrintShadowByte(str, "  Global redzone:          ", kAsanGlobalRedzoneMagic);
 525   PrintShadowByte(str, "  Global init order:       ",
 526                   kAsanInitializationOrderMagic);
 527   PrintShadowByte(str, "  Poisoned by user:        ",
 528                   kAsanUserPoisonedMemoryMagic);
 529   PrintShadowByte(str, "  Container overflow:      ",
 530                   kAsanContiguousContainerOOBMagic);
 531   PrintShadowByte(str, "  Array cookie:            ",
 532                   kAsanArrayCookieMagic);
 533   PrintShadowByte(str, "  Intra object redzone:    ",
 534                   kAsanIntraObjectRedzone);
 535   PrintShadowByte(str, "  ASan internal:           ", kAsanInternalHeapMagic);
 536   PrintShadowByte(str, "  Left alloca redzone:     ", kAsanAllocaLeftMagic);
 537   PrintShadowByte(str, "  Right alloca redzone:    ", kAsanAllocaRightMagic);
 538 }
 539
 540 static void PrintShadowBytes(InternalScopedString *str, const char *before,
 541                              u8 *bytes, u8 *guilty, uptr n) {
 542   Decorator d;
 543   if (before)
 544     str->append("%s%p:", before, (void *)bytes);
 545   for (uptr i = 0; i < n; i++) {
 546     u8 *p = bytes + i;
 547     const char *before =
 548         p == guilty ? "[" : (p - 1 == guilty && i != 0) ? "" : " ";
 549     const char *after = p == guilty ? "]" : "";
 550     PrintShadowByte(str, before, *p, after);
 551   }
 552   str->append("\n");
 553 }
 554
 555 static void PrintShadowMemoryForAddress(uptr addr) {
 556   if (!AddrIsInMem(addr)) return;
 557   uptr shadow_addr = MemToShadow(addr);
 558   const uptr n_bytes_per_row = 16;
 559   uptr aligned_shadow = shadow_addr & ~(n_bytes_per_row - 1);
 560   InternalScopedString str;
 561   str.append("Shadow bytes around the buggy address:\n");
 562   for (int i = -5; i <= 5; i++) {
 563     uptr row_shadow_addr = aligned_shadow + i * n_bytes_per_row;
 564     // Skip rows that would be outside the shadow range. This can happen when
 565     // the user address is near the bottom, top, or shadow gap of the address
 566     // space.
 567     if (!AddrIsInShadow(row_shadow_addr)) continue;
 568     const char *prefix = (i == 0) ? "=>" : "  ";
 569     PrintShadowBytes(&str, prefix, (u8 *)row_shadow_addr, (u8 *)shadow_addr,
 570                      n_bytes_per_row);
 571   }
 572   if (flags()->print_legend) PrintLegend(&str);
 573   Printf("%s", str.data());
 574 }
 575
 576 void ErrorGeneric::Print() {
 577   Decorator d;
 578   Printf("%s", d.Error());
 579   uptr addr = addr_description.Address();
 580   Report("ERROR: AddressSanitizer: %s on address %p at pc %p bp %p sp %p\n",
 581          bug_descr, (void *)addr, (void *)pc, (void *)bp, (void *)sp);
 582   Printf("%s", d.Default());
 583
 584   Printf("%s%s of size %zu at %p thread %s%s\n", d.Access(),
 585          access_size ? (is_write ? "WRITE" : "READ") : "ACCESS", access_size,
 586          (void *)addr, AsanThreadIdAndName(tid).c_str(), d.Default());
 587
 588   scariness.Print();
 589   GET_STACK_TRACE_FATAL(pc, bp);
 590   stack.Print();
 591
 592   // Pass bug_descr because we have a special case for
 593   // initialization-order-fiasco
 594   addr_description.Print(bug_descr);
 595   if (shadow_val == kAsanContiguousContainerOOBMagic)
 596     PrintContainerOverflowHint();
 597   ReportErrorSummary(bug_descr, &stack);
 598   PrintShadowMemoryForAddress(addr);
 599 }
 600
 601 }  // namespace __asan