libsanitizer/asan/asan_errors.cc

   1 //===-- asan_errors.cc ------------------------------------------*- C++ -*-===//
   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 // ASan implementation for error structures.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "asan_errors.h"
  14 #include <signal.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 void ErrorStackOverflow::Print() {
  24   Decorator d;
  25   Printf("%s", d.Warning());
  26   Report(
  27       "ERROR: AddressSanitizer: stack-overflow on address %p"
  28       " (pc %p bp %p sp %p T%d)\n",
  29       (void *)addr, (void *)pc, (void *)bp, (void *)sp, tid);
  30   Printf("%s", d.EndWarning());
  31   scariness.Print();
  32   BufferedStackTrace stack;
  33   GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, context,
  34                                   common_flags()->fast_unwind_on_fatal);
  35   stack.Print();
  36   ReportErrorSummary("stack-overflow", &stack);
  37 }
  38
  39 static void MaybeDumpInstructionBytes(uptr pc) {
  40   if (!flags()->dump_instruction_bytes || (pc < GetPageSizeCached())) return;
  41   InternalScopedString str(1024);
  42   str.append("First 16 instruction bytes at pc: ");
  43   if (IsAccessibleMemoryRange(pc, 16)) {
  44     for (int i = 0; i < 16; ++i) {
  45       PrintMemoryByte(&str, "", ((u8 *)pc)[i], /*in_shadow*/ false, " ");
  46     }
  47     str.append("\n");
  48   } else {
  49     str.append("unaccessible\n");
  50   }
  51   Report("%s", str.data());
  52 }
  53
  54 void ErrorDeadlySignal::Print() {
  55   Decorator d;
  56   Printf("%s", d.Warning());
  57   const char *description = DescribeSignalOrException(signo);
  58   Report(
  59       "ERROR: AddressSanitizer: %s on unknown address %p (pc %p bp %p sp %p "
  60       "T%d)\n",
  61       description, (void *)addr, (void *)pc, (void *)bp, (void *)sp, tid);
  62   Printf("%s", d.EndWarning());
  63   if (pc < GetPageSizeCached()) Report("Hint: pc points to the zero page.\n");
  64   if (is_memory_access) {
  65     const char *access_type =
  66         write_flag == SignalContext::WRITE
  67             ? "WRITE"
  68             : (write_flag == SignalContext::READ ? "READ" : "UNKNOWN");
  69     Report("The signal is caused by a %s memory access.\n", access_type);
  70     if (addr < GetPageSizeCached())
  71       Report("Hint: address points to the zero page.\n");
  72   }
  73   scariness.Print();
  74   BufferedStackTrace stack;
  75   GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, context,
  76                                   common_flags()->fast_unwind_on_fatal);
  77   stack.Print();
  78   MaybeDumpInstructionBytes(pc);
  79   Printf("AddressSanitizer can not provide additional info.\n");
  80   ReportErrorSummary(description, &stack);
  81 }
  82
  83 void ErrorDoubleFree::Print() {
  84   Decorator d;
  85   Printf("%s", d.Warning());
  86   char tname[128];
  87   Report(
  88       "ERROR: AddressSanitizer: attempting double-free on %p in "
  89       "thread T%d%s:\n",
  90       addr_description.addr, tid,
  91       ThreadNameWithParenthesis(tid, tname, sizeof(tname)));
  92   Printf("%s", d.EndWarning());
  93   scariness.Print();
  94   GET_STACK_TRACE_FATAL(second_free_stack->trace[0],
  95                         second_free_stack->top_frame_bp);
  96   stack.Print();
  97   addr_description.Print();
  98   ReportErrorSummary("double-free", &stack);
  99 }
 100
 101 void ErrorNewDeleteSizeMismatch::Print() {
 102   Decorator d;
 103   Printf("%s", d.Warning());
 104   char tname[128];
 105   Report(
 106       "ERROR: AddressSanitizer: new-delete-type-mismatch on %p in thread "
 107       "T%d%s:\n",
 108       addr_description.addr, tid,
 109       ThreadNameWithParenthesis(tid, tname, sizeof(tname)));
 110   Printf("%s  object passed to delete has wrong type:\n", d.EndWarning());
 111   Printf(
 112       "  size of the allocated type:   %zd bytes;\n"
 113       "  size of the deallocated type: %zd bytes.\n",
 114       addr_description.chunk_access.chunk_size, delete_size);
 115   CHECK_GT(free_stack->size, 0);
 116   scariness.Print();
 117   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
 118   stack.Print();
 119   addr_description.Print();
 120   ReportErrorSummary("new-delete-type-mismatch", &stack);
 121   Report(
 122       "HINT: if you don't care about these errors you may set "
 123       "ASAN_OPTIONS=new_delete_type_mismatch=0\n");
 124 }
 125
 126 void ErrorFreeNotMalloced::Print() {
 127   Decorator d;
 128   Printf("%s", d.Warning());
 129   char tname[128];
 130   Report(
 131       "ERROR: AddressSanitizer: attempting free on address "
 132       "which was not malloc()-ed: %p in thread T%d%s\n",
 133       addr_description.Address(), tid,
 134       ThreadNameWithParenthesis(tid, tname, sizeof(tname)));
 135   Printf("%s", d.EndWarning());
 136   CHECK_GT(free_stack->size, 0);
 137   scariness.Print();
 138   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
 139   stack.Print();
 140   addr_description.Print();
 141   ReportErrorSummary("bad-free", &stack);
 142 }
 143
 144 void ErrorAllocTypeMismatch::Print() {
 145   static const char *alloc_names[] = {"INVALID", "malloc", "operator new",
 146                                       "operator new []"};
 147   static const char *dealloc_names[] = {"INVALID", "free", "operator delete",
 148                                         "operator delete []"};
 149   CHECK_NE(alloc_type, dealloc_type);
 150   Decorator d;
 151   Printf("%s", d.Warning());
 152   Report("ERROR: AddressSanitizer: alloc-dealloc-mismatch (%s vs %s) on %p\n",
 153          alloc_names[alloc_type], dealloc_names[dealloc_type],
 154          addr_description.addr);
 155   Printf("%s", d.EndWarning());
 156   CHECK_GT(dealloc_stack->size, 0);
 157   scariness.Print();
 158   GET_STACK_TRACE_FATAL(dealloc_stack->trace[0], dealloc_stack->top_frame_bp);
 159   stack.Print();
 160   addr_description.Print();
 161   ReportErrorSummary("alloc-dealloc-mismatch", &stack);
 162   Report(
 163       "HINT: if you don't care about these errors you may set "
 164       "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
 165 }
 166
 167 void ErrorMallocUsableSizeNotOwned::Print() {
 168   Decorator d;
 169   Printf("%s", d.Warning());
 170   Report(
 171       "ERROR: AddressSanitizer: attempting to call malloc_usable_size() for "
 172       "pointer which is not owned: %p\n",
 173       addr_description.Address());
 174   Printf("%s", d.EndWarning());
 175   stack->Print();
 176   addr_description.Print();
 177   ReportErrorSummary("bad-malloc_usable_size", stack);
 178 }
 179
 180 void ErrorSanitizerGetAllocatedSizeNotOwned::Print() {
 181   Decorator d;
 182   Printf("%s", d.Warning());
 183   Report(
 184       "ERROR: AddressSanitizer: attempting to call "
 185       "__sanitizer_get_allocated_size() for pointer which is not owned: %p\n",
 186       addr_description.Address());
 187   Printf("%s", d.EndWarning());
 188   stack->Print();
 189   addr_description.Print();
 190   ReportErrorSummary("bad-__sanitizer_get_allocated_size", stack);
 191 }
 192
 193 void ErrorStringFunctionMemoryRangesOverlap::Print() {
 194   Decorator d;
 195   char bug_type[100];
 196   internal_snprintf(bug_type, sizeof(bug_type), "%s-param-overlap", function);
 197   Printf("%s", d.Warning());
 198   Report(
 199       "ERROR: AddressSanitizer: %s: memory ranges [%p,%p) and [%p, %p) "
 200       "overlap\n",
 201       bug_type, addr1_description.Address(),
 202       addr1_description.Address() + length1, addr2_description.Address(),
 203       addr2_description.Address() + length2);
 204   Printf("%s", d.EndWarning());
 205   scariness.Print();
 206   stack->Print();
 207   addr1_description.Print();
 208   addr2_description.Print();
 209   ReportErrorSummary(bug_type, stack);
 210 }
 211
 212 void ErrorStringFunctionSizeOverflow::Print() {
 213   Decorator d;
 214   Printf("%s", d.Warning());
 215   const char *bug_type = "negative-size-param";
 216   Report("ERROR: AddressSanitizer: %s: (size=%zd)\n", bug_type, size);
 217   Printf("%s", d.EndWarning());
 218   scariness.Print();
 219   stack->Print();
 220   addr_description.Print();
 221   ReportErrorSummary(bug_type, stack);
 222 }
 223
 224 void ErrorBadParamsToAnnotateContiguousContainer::Print() {
 225   Report(
 226       "ERROR: AddressSanitizer: bad parameters to "
 227       "__sanitizer_annotate_contiguous_container:\n"
 228       "      beg     : %p\n"
 229       "      end     : %p\n"
 230       "      old_mid : %p\n"
 231       "      new_mid : %p\n",
 232       beg, end, old_mid, new_mid);
 233   uptr granularity = SHADOW_GRANULARITY;
 234   if (!IsAligned(beg, granularity))
 235     Report("ERROR: beg is not aligned by %d\n", granularity);
 236   stack->Print();
 237   ReportErrorSummary("bad-__sanitizer_annotate_contiguous_container", stack);
 238 }
 239
 240 void ErrorODRViolation::Print() {
 241   Decorator d;
 242   Printf("%s", d.Warning());
 243   Report("ERROR: AddressSanitizer: odr-violation (%p):\n", global1.beg);
 244   Printf("%s", d.EndWarning());
 245   InternalScopedString g1_loc(256), g2_loc(256);
 246   PrintGlobalLocation(&g1_loc, global1);
 247   PrintGlobalLocation(&g2_loc, global2);
 248   Printf("  [1] size=%zd '%s' %s\n", global1.size,
 249          MaybeDemangleGlobalName(global1.name), g1_loc.data());
 250   Printf("  [2] size=%zd '%s' %s\n", global2.size,
 251          MaybeDemangleGlobalName(global2.name), g2_loc.data());
 252   if (stack_id1 && stack_id2) {
 253     Printf("These globals were registered at these points:\n");
 254     Printf("  [1]:\n");
 255     StackDepotGet(stack_id1).Print();
 256     Printf("  [2]:\n");
 257     StackDepotGet(stack_id2).Print();
 258   }
 259   Report(
 260       "HINT: if you don't care about these errors you may set "
 261       "ASAN_OPTIONS=detect_odr_violation=0\n");
 262   InternalScopedString error_msg(256);
 263   error_msg.append("odr-violation: global '%s' at %s",
 264                    MaybeDemangleGlobalName(global1.name), g1_loc.data());
 265   ReportErrorSummary(error_msg.data());
 266 }
 267
 268 void ErrorInvalidPointerPair::Print() {
 269   const char *bug_type = "invalid-pointer-pair";
 270   Decorator d;
 271   Printf("%s", d.Warning());
 272   Report("ERROR: AddressSanitizer: invalid-pointer-pair: %p %p\n",
 273          addr1_description.Address(), addr2_description.Address());
 274   Printf("%s", d.EndWarning());
 275   GET_STACK_TRACE_FATAL(pc, bp);
 276   stack.Print();
 277   addr1_description.Print();
 278   addr2_description.Print();
 279   ReportErrorSummary(bug_type, &stack);
 280 }
 281
 282 static bool AdjacentShadowValuesAreFullyPoisoned(u8 *s) {
 283   return s[-1] > 127 && s[1] > 127;
 284 }
 285
 286 ErrorGeneric::ErrorGeneric(u32 tid, uptr pc_, uptr bp_, uptr sp_, uptr addr,
 287                            bool is_write_, uptr access_size_)
 288     : ErrorBase(tid),
 289       addr_description(addr, access_size_, /*shouldLockThreadRegistry=*/false),
 290       pc(pc_),
 291       bp(bp_),
 292       sp(sp_),
 293       access_size(access_size_),
 294       is_write(is_write_),
 295       shadow_val(0) {
 296   scariness.Clear();
 297   if (access_size) {
 298     if (access_size <= 9) {
 299       char desr[] = "?-byte";
 300       desr[0] = '0' + access_size;
 301       scariness.Scare(access_size + access_size / 2, desr);
 302     } else if (access_size >= 10) {
 303       scariness.Scare(15, "multi-byte");
 304     }
 305     is_write ? scariness.Scare(20, "write") : scariness.Scare(1, "read");
 306
 307     // Determine the error type.
 308     bug_descr = "unknown-crash";
 309     if (AddrIsInMem(addr)) {
 310       u8 *shadow_addr = (u8 *)MemToShadow(addr);
 311       // If we are accessing 16 bytes, look at the second shadow byte.
 312       if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY) shadow_addr++;
 313       // If we are in the partial right redzone, look at the next shadow byte.
 314       if (*shadow_addr > 0 && *shadow_addr < 128) shadow_addr++;
 315       bool far_from_bounds = false;
 316       shadow_val = *shadow_addr;
 317       int bug_type_score = 0;
 318       // For use-after-frees reads are almost as bad as writes.
 319       int read_after_free_bonus = 0;
 320       switch (shadow_val) {
 321         case kAsanHeapLeftRedzoneMagic:
 322         case kAsanArrayCookieMagic:
 323           bug_descr = "heap-buffer-overflow";
 324           bug_type_score = 10;
 325           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 326           break;
 327         case kAsanHeapFreeMagic:
 328           bug_descr = "heap-use-after-free";
 329           bug_type_score = 20;
 330           if (!is_write) read_after_free_bonus = 18;
 331           break;
 332         case kAsanStackLeftRedzoneMagic:
 333           bug_descr = "stack-buffer-underflow";
 334           bug_type_score = 25;
 335           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 336           break;
 337         case kAsanInitializationOrderMagic:
 338           bug_descr = "initialization-order-fiasco";
 339           bug_type_score = 1;
 340           break;
 341         case kAsanStackMidRedzoneMagic:
 342         case kAsanStackRightRedzoneMagic:
 343           bug_descr = "stack-buffer-overflow";
 344           bug_type_score = 25;
 345           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 346           break;
 347         case kAsanStackAfterReturnMagic:
 348           bug_descr = "stack-use-after-return";
 349           bug_type_score = 30;
 350           if (!is_write) read_after_free_bonus = 18;
 351           break;
 352         case kAsanUserPoisonedMemoryMagic:
 353           bug_descr = "use-after-poison";
 354           bug_type_score = 20;
 355           break;
 356         case kAsanContiguousContainerOOBMagic:
 357           bug_descr = "container-overflow";
 358           bug_type_score = 10;
 359           break;
 360         case kAsanStackUseAfterScopeMagic:
 361           bug_descr = "stack-use-after-scope";
 362           bug_type_score = 10;
 363           break;
 364         case kAsanGlobalRedzoneMagic:
 365           bug_descr = "global-buffer-overflow";
 366           bug_type_score = 10;
 367           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 368           break;
 369         case kAsanIntraObjectRedzone:
 370           bug_descr = "intra-object-overflow";
 371           bug_type_score = 10;
 372           break;
 373         case kAsanAllocaLeftMagic:
 374         case kAsanAllocaRightMagic:
 375           bug_descr = "dynamic-stack-buffer-overflow";
 376           bug_type_score = 25;
 377           far_from_bounds = AdjacentShadowValuesAreFullyPoisoned(shadow_addr);
 378           break;
 379       }
 380       scariness.Scare(bug_type_score + read_after_free_bonus, bug_descr);
 381       if (far_from_bounds) scariness.Scare(10, "far-from-bounds");
 382     }
 383   }
 384 }
 385
 386 static void PrintContainerOverflowHint() {
 387   Printf("HINT: if you don't care about these errors you may set "
 388          "ASAN_OPTIONS=detect_container_overflow=0.\n"
 389          "If you suspect a false positive see also: "
 390          "https://github.com/google/sanitizers/wiki/"
 391          "AddressSanitizerContainerOverflow.\n");
 392 }
 393
 394 static void PrintShadowByte(InternalScopedString *str, const char *before,
 395     u8 byte, const char *after = "\n") {
 396   PrintMemoryByte(str, before, byte, /*in_shadow*/true, after);
 397 }
 398
 399 static void PrintLegend(InternalScopedString *str) {
 400   str->append(
 401       "Shadow byte legend (one shadow byte represents %d "
 402       "application bytes):\n",
 403       (int)SHADOW_GRANULARITY);
 404   PrintShadowByte(str, "  Addressable:           ", 0);
 405   str->append("  Partially addressable: ");
 406   for (u8 i = 1; i < SHADOW_GRANULARITY; i++) PrintShadowByte(str, "", i, " ");
 407   str->append("\n");
 408   PrintShadowByte(str, "  Heap left redzone:       ",
 409                   kAsanHeapLeftRedzoneMagic);
 410   PrintShadowByte(str, "  Freed heap region:       ", kAsanHeapFreeMagic);
 411   PrintShadowByte(str, "  Stack left redzone:      ",
 412                   kAsanStackLeftRedzoneMagic);
 413   PrintShadowByte(str, "  Stack mid redzone:       ",
 414                   kAsanStackMidRedzoneMagic);
 415   PrintShadowByte(str, "  Stack right redzone:     ",
 416                   kAsanStackRightRedzoneMagic);
 417   PrintShadowByte(str, "  Stack after return:      ",
 418                   kAsanStackAfterReturnMagic);
 419   PrintShadowByte(str, "  Stack use after scope:   ",
 420                   kAsanStackUseAfterScopeMagic);
 421   PrintShadowByte(str, "  Global redzone:          ", kAsanGlobalRedzoneMagic);
 422   PrintShadowByte(str, "  Global init order:       ",
 423                   kAsanInitializationOrderMagic);
 424   PrintShadowByte(str, "  Poisoned by user:        ",
 425                   kAsanUserPoisonedMemoryMagic);
 426   PrintShadowByte(str, "  Container overflow:      ",
 427                   kAsanContiguousContainerOOBMagic);
 428   PrintShadowByte(str, "  Array cookie:            ",
 429                   kAsanArrayCookieMagic);
 430   PrintShadowByte(str, "  Intra object redzone:    ",
 431                   kAsanIntraObjectRedzone);
 432   PrintShadowByte(str, "  ASan internal:           ", kAsanInternalHeapMagic);
 433   PrintShadowByte(str, "  Left alloca redzone:     ", kAsanAllocaLeftMagic);
 434   PrintShadowByte(str, "  Right alloca redzone:    ", kAsanAllocaRightMagic);
 435 }
 436
 437 static void PrintShadowBytes(InternalScopedString *str, const char *before,
 438                              u8 *bytes, u8 *guilty, uptr n) {
 439   Decorator d;
 440   if (before) str->append("%s%p:", before, bytes);
 441   for (uptr i = 0; i < n; i++) {
 442     u8 *p = bytes + i;
 443     const char *before =
 444         p == guilty ? "[" : (p - 1 == guilty && i != 0) ? "" : " ";
 445     const char *after = p == guilty ? "]" : "";
 446     PrintShadowByte(str, before, *p, after);
 447   }
 448   str->append("\n");
 449 }
 450
 451 static void PrintShadowMemoryForAddress(uptr addr) {
 452   if (!AddrIsInMem(addr)) return;
 453   uptr shadow_addr = MemToShadow(addr);
 454   const uptr n_bytes_per_row = 16;
 455   uptr aligned_shadow = shadow_addr & ~(n_bytes_per_row - 1);
 456   InternalScopedString str(4096 * 8);
 457   str.append("Shadow bytes around the buggy address:\n");
 458   for (int i = -5; i <= 5; i++) {
 459     const char *prefix = (i == 0) ? "=>" : "  ";
 460     PrintShadowBytes(&str, prefix, (u8 *)(aligned_shadow + i * n_bytes_per_row),
 461                      (u8 *)shadow_addr, n_bytes_per_row);
 462   }
 463   if (flags()->print_legend) PrintLegend(&str);
 464   Printf("%s", str.data());
 465 }
 466
 467 void ErrorGeneric::Print() {
 468   Decorator d;
 469   Printf("%s", d.Warning());
 470   uptr addr = addr_description.Address();
 471   Report("ERROR: AddressSanitizer: %s on address %p at pc %p bp %p sp %p\n",
 472          bug_descr, (void *)addr, pc, bp, sp);
 473   Printf("%s", d.EndWarning());
 474
 475   char tname[128];
 476   Printf("%s%s of size %zu at %p thread T%d%s%s\n", d.Access(),
 477          access_size ? (is_write ? "WRITE" : "READ") : "ACCESS", access_size,
 478          (void *)addr, tid,
 479          ThreadNameWithParenthesis(tid, tname, sizeof(tname)), d.EndAccess());
 480
 481   scariness.Print();
 482   GET_STACK_TRACE_FATAL(pc, bp);
 483   stack.Print();
 484
 485   // Pass bug_descr because we have a special case for
 486   // initialization-order-fiasco
 487   addr_description.Print(bug_descr);
 488   if (shadow_val == kAsanContiguousContainerOOBMagic)
 489     PrintContainerOverflowHint();
 490   ReportErrorSummary(bug_descr, &stack);
 491   PrintShadowMemoryForAddress(addr);
 492 }
 493
 494 }  // namespace __asan