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