libsanitizer/asan/asan_report.cc

   1 //===-- asan_report.cc ----------------------------------------------------===//
   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 // This file contains error reporting code.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "asan_errors.h"
  14 #include "asan_flags.h"
  15 #include "asan_descriptions.h"
  16 #include "asan_internal.h"
  17 #include "asan_mapping.h"
  18 #include "asan_report.h"
  19 #include "asan_scariness_score.h"
  20 #include "asan_stack.h"
  21 #include "asan_thread.h"
  22 #include "sanitizer_common/sanitizer_common.h"
  23 #include "sanitizer_common/sanitizer_flags.h"
  24 #include "sanitizer_common/sanitizer_report_decorator.h"
  25 #include "sanitizer_common/sanitizer_stackdepot.h"
  26 #include "sanitizer_common/sanitizer_symbolizer.h"
  27
  28 namespace __asan {
  29
  30 // -------------------- User-specified callbacks ----------------- {{{1
  31 static void (*error_report_callback)(const char*);
  32 static char *error_message_buffer = nullptr;
  33 static uptr error_message_buffer_pos = 0;
  34 static BlockingMutex error_message_buf_mutex(LINKER_INITIALIZED);
  35 static const unsigned kAsanBuggyPcPoolSize = 25;
  36 static __sanitizer::atomic_uintptr_t AsanBuggyPcPool[kAsanBuggyPcPoolSize];
  37
  38 void AppendToErrorMessageBuffer(const char *buffer) {
  39   BlockingMutexLock l(&error_message_buf_mutex);
  40   if (!error_message_buffer) {
  41     error_message_buffer =
  42       (char*)MmapOrDieQuietly(kErrorMessageBufferSize, __func__);
  43     error_message_buffer_pos = 0;
  44   }
  45   uptr length = internal_strlen(buffer);
  46   RAW_CHECK(kErrorMessageBufferSize >= error_message_buffer_pos);
  47   uptr remaining = kErrorMessageBufferSize - error_message_buffer_pos;
  48   internal_strncpy(error_message_buffer + error_message_buffer_pos,
  49                    buffer, remaining);
  50   error_message_buffer[kErrorMessageBufferSize - 1] = '\0';
  51   // FIXME: reallocate the buffer instead of truncating the message.
  52   error_message_buffer_pos += Min(remaining, length);
  53 }
  54
  55 // ---------------------- Helper functions ----------------------- {{{1
  56
  57 void PrintMemoryByte(InternalScopedString *str, const char *before, u8 byte,
  58                      bool in_shadow, const char *after) {
  59   Decorator d;
  60   str->append("%s%s%x%x%s%s", before,
  61               in_shadow ? d.ShadowByte(byte) : d.MemoryByte(), byte >> 4,
  62               byte & 15, d.Default(), after);
  63 }
  64
  65 static void PrintZoneForPointer(uptr ptr, uptr zone_ptr,
  66                                 const char *zone_name) {
  67   if (zone_ptr) {
  68     if (zone_name) {
  69       Printf("malloc_zone_from_ptr(%p) = %p, which is %s\n",
  70                  ptr, zone_ptr, zone_name);
  71     } else {
  72       Printf("malloc_zone_from_ptr(%p) = %p, which doesn't have a name\n",
  73                  ptr, zone_ptr);
  74     }
  75   } else {
  76     Printf("malloc_zone_from_ptr(%p) = 0\n", ptr);
  77   }
  78 }
  79
  80 // ---------------------- Address Descriptions ------------------- {{{1
  81
  82 bool ParseFrameDescription(const char *frame_descr,
  83                            InternalMmapVector<StackVarDescr> *vars) {
  84   CHECK(frame_descr);
  85   char *p;
  86   // This string is created by the compiler and has the following form:
  87   // "n alloc_1 alloc_2 ... alloc_n"
  88   // where alloc_i looks like "offset size len ObjectName"
  89   // or                       "offset size len ObjectName:line".
  90   uptr n_objects = (uptr)internal_simple_strtoll(frame_descr, &p, 10);
  91   if (n_objects == 0)
  92     return false;
  93
  94   for (uptr i = 0; i < n_objects; i++) {
  95     uptr beg  = (uptr)internal_simple_strtoll(p, &p, 10);
  96     uptr size = (uptr)internal_simple_strtoll(p, &p, 10);
  97     uptr len  = (uptr)internal_simple_strtoll(p, &p, 10);
  98     if (beg == 0 || size == 0 || *p != ' ') {
  99       return false;
 100     }
 101     p++;
 102     char *colon_pos = internal_strchr(p, ':');
 103     uptr line = 0;
 104     uptr name_len = len;
 105     if (colon_pos != nullptr && colon_pos < p + len) {
 106       name_len = colon_pos - p;
 107       line = (uptr)internal_simple_strtoll(colon_pos + 1, nullptr, 10);
 108     }
 109     StackVarDescr var = {beg, size, p, name_len, line};
 110     vars->push_back(var);
 111     p += len;
 112   }
 113
 114   return true;
 115 }
 116
 117 // -------------------- Different kinds of reports ----------------- {{{1
 118
 119 // Use ScopedInErrorReport to run common actions just before and
 120 // immediately after printing error report.
 121 class ScopedInErrorReport {
 122  public:
 123   explicit ScopedInErrorReport(bool fatal = false)
 124       : halt_on_error_(fatal || flags()->halt_on_error) {
 125     // Make sure the registry and sanitizer report mutexes are locked while
 126     // we're printing an error report.
 127     // We can lock them only here to avoid self-deadlock in case of
 128     // recursive reports.
 129     asanThreadRegistry().Lock();
 130     Printf(
 131         "=================================================================\n");
 132   }
 133
 134   ~ScopedInErrorReport() {
 135     ASAN_ON_ERROR();
 136     if (current_error_.IsValid()) current_error_.Print();
 137
 138     // Make sure the current thread is announced.
 139     DescribeThread(GetCurrentThread());
 140     // We may want to grab this lock again when printing stats.
 141     asanThreadRegistry().Unlock();
 142     // Print memory stats.
 143     if (flags()->print_stats)
 144       __asan_print_accumulated_stats();
 145
 146     if (common_flags()->print_cmdline)
 147       PrintCmdline();
 148
 149     if (common_flags()->print_module_map == 2) PrintModuleMap();
 150
 151     // Copy the message buffer so that we could start logging without holding a
 152     // lock that gets aquired during printing.
 153     InternalScopedBuffer<char> buffer_copy(kErrorMessageBufferSize);
 154     {
 155       BlockingMutexLock l(&error_message_buf_mutex);
 156       internal_memcpy(buffer_copy.data(),
 157                       error_message_buffer, kErrorMessageBufferSize);
 158     }
 159
 160     LogFullErrorReport(buffer_copy.data());
 161
 162     if (error_report_callback) {
 163       error_report_callback(buffer_copy.data());
 164     }
 165
 166     if (halt_on_error_ && common_flags()->abort_on_error) {
 167       // On Android the message is truncated to 512 characters.
 168       // FIXME: implement "compact" error format, possibly without, or with
 169       // highly compressed stack traces?
 170       // FIXME: or just use the summary line as abort message?
 171       SetAbortMessage(buffer_copy.data());
 172     }
 173
 174     // In halt_on_error = false mode, reset the current error object (before
 175     // unlocking).
 176     if (!halt_on_error_)
 177       internal_memset(&current_error_, 0, sizeof(current_error_));
 178
 179     if (halt_on_error_) {
 180       Report("ABORTING\n");
 181       Die();
 182     }
 183   }
 184
 185   void ReportError(const ErrorDescription &description) {
 186     // Can only report one error per ScopedInErrorReport.
 187     CHECK_EQ(current_error_.kind, kErrorKindInvalid);
 188     current_error_ = description;
 189   }
 190
 191   static ErrorDescription &CurrentError() {
 192     return current_error_;
 193   }
 194
 195  private:
 196   ScopedErrorReportLock error_report_lock_;
 197   // Error currently being reported. This enables the destructor to interact
 198   // with the debugger and point it to an error description.
 199   static ErrorDescription current_error_;
 200   bool halt_on_error_;
 201 };
 202
 203 ErrorDescription ScopedInErrorReport::current_error_;
 204
 205 void ReportDeadlySignal(const SignalContext &sig) {
 206   ScopedInErrorReport in_report(/*fatal*/ true);
 207   ErrorDeadlySignal error(GetCurrentTidOrInvalid(), sig);
 208   in_report.ReportError(error);
 209 }
 210
 211 void ReportDoubleFree(uptr addr, BufferedStackTrace *free_stack) {
 212   ScopedInErrorReport in_report;
 213   ErrorDoubleFree error(GetCurrentTidOrInvalid(), free_stack, addr);
 214   in_report.ReportError(error);
 215 }
 216
 217 void ReportNewDeleteSizeMismatch(uptr addr, uptr delete_size,
 218                                  BufferedStackTrace *free_stack) {
 219   ScopedInErrorReport in_report;
 220   ErrorNewDeleteSizeMismatch error(GetCurrentTidOrInvalid(), free_stack, addr,
 221                                    delete_size);
 222   in_report.ReportError(error);
 223 }
 224
 225 void ReportFreeNotMalloced(uptr addr, BufferedStackTrace *free_stack) {
 226   ScopedInErrorReport in_report;
 227   ErrorFreeNotMalloced error(GetCurrentTidOrInvalid(), free_stack, addr);
 228   in_report.ReportError(error);
 229 }
 230
 231 void ReportAllocTypeMismatch(uptr addr, BufferedStackTrace *free_stack,
 232                              AllocType alloc_type,
 233                              AllocType dealloc_type) {
 234   ScopedInErrorReport in_report;
 235   ErrorAllocTypeMismatch error(GetCurrentTidOrInvalid(), free_stack, addr,
 236                                alloc_type, dealloc_type);
 237   in_report.ReportError(error);
 238 }
 239
 240 void ReportMallocUsableSizeNotOwned(uptr addr, BufferedStackTrace *stack) {
 241   ScopedInErrorReport in_report;
 242   ErrorMallocUsableSizeNotOwned error(GetCurrentTidOrInvalid(), stack, addr);
 243   in_report.ReportError(error);
 244 }
 245
 246 void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr,
 247                                              BufferedStackTrace *stack) {
 248   ScopedInErrorReport in_report;
 249   ErrorSanitizerGetAllocatedSizeNotOwned error(GetCurrentTidOrInvalid(), stack,
 250                                                addr);
 251   in_report.ReportError(error);
 252 }
 253
 254 void ReportStringFunctionMemoryRangesOverlap(const char *function,
 255                                              const char *offset1, uptr length1,
 256                                              const char *offset2, uptr length2,
 257                                              BufferedStackTrace *stack) {
 258   ScopedInErrorReport in_report;
 259   ErrorStringFunctionMemoryRangesOverlap error(
 260       GetCurrentTidOrInvalid(), stack, (uptr)offset1, length1, (uptr)offset2,
 261       length2, function);
 262   in_report.ReportError(error);
 263 }
 264
 265 void ReportStringFunctionSizeOverflow(uptr offset, uptr size,
 266                                       BufferedStackTrace *stack) {
 267   ScopedInErrorReport in_report;
 268   ErrorStringFunctionSizeOverflow error(GetCurrentTidOrInvalid(), stack, offset,
 269                                         size);
 270   in_report.ReportError(error);
 271 }
 272
 273 void ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end,
 274                                                   uptr old_mid, uptr new_mid,
 275                                                   BufferedStackTrace *stack) {
 276   ScopedInErrorReport in_report;
 277   ErrorBadParamsToAnnotateContiguousContainer error(
 278       GetCurrentTidOrInvalid(), stack, beg, end, old_mid, new_mid);
 279   in_report.ReportError(error);
 280 }
 281
 282 void ReportODRViolation(const __asan_global *g1, u32 stack_id1,
 283                         const __asan_global *g2, u32 stack_id2) {
 284   ScopedInErrorReport in_report;
 285   ErrorODRViolation error(GetCurrentTidOrInvalid(), g1, stack_id1, g2,
 286                           stack_id2);
 287   in_report.ReportError(error);
 288 }
 289
 290 // ----------------------- CheckForInvalidPointerPair ----------- {{{1
 291 static NOINLINE void ReportInvalidPointerPair(uptr pc, uptr bp, uptr sp,
 292                                               uptr a1, uptr a2) {
 293   ScopedInErrorReport in_report;
 294   ErrorInvalidPointerPair error(GetCurrentTidOrInvalid(), pc, bp, sp, a1, a2);
 295   in_report.ReportError(error);
 296 }
 297
 298 static bool IsInvalidPointerPair(uptr a1, uptr a2) {
 299   if (a1 == a2)
 300     return false;
 301
 302   // 256B in shadow memory can be iterated quite fast
 303   static const uptr kMaxOffset = 2048;
 304
 305   uptr left = a1 < a2 ? a1 : a2;
 306   uptr right = a1 < a2 ? a2 : a1;
 307   uptr offset = right - left;
 308   if (offset <= kMaxOffset)
 309     return __asan_region_is_poisoned(left, offset);
 310
 311   AsanThread *t = GetCurrentThread();
 312
 313   // check whether left is a stack memory pointer
 314   if (uptr shadow_offset1 = t->GetStackVariableShadowStart(left)) {
 315     uptr shadow_offset2 = t->GetStackVariableShadowStart(right);
 316     return shadow_offset2 == 0 || shadow_offset1 != shadow_offset2;
 317   }
 318
 319   // check whether left is a heap memory address
 320   HeapAddressDescription hdesc1, hdesc2;
 321   if (GetHeapAddressInformation(left, 0, &hdesc1) &&
 322       hdesc1.chunk_access.access_type == kAccessTypeInside)
 323     return !GetHeapAddressInformation(right, 0, &hdesc2) ||
 324         hdesc2.chunk_access.access_type != kAccessTypeInside ||
 325         hdesc1.chunk_access.chunk_begin != hdesc2.chunk_access.chunk_begin;
 326
 327   // check whether left is an address of a global variable
 328   GlobalAddressDescription gdesc1, gdesc2;
 329   if (GetGlobalAddressInformation(left, 0, &gdesc1))
 330     return !GetGlobalAddressInformation(right - 1, 0, &gdesc2) ||
 331         !gdesc1.PointsInsideTheSameVariable(gdesc2);
 332
 333   if (t->GetStackVariableShadowStart(right) ||
 334       GetHeapAddressInformation(right, 0, &hdesc2) ||
 335       GetGlobalAddressInformation(right - 1, 0, &gdesc2))
 336     return true;
 337
 338   // At this point we know nothing about both a1 and a2 addresses.
 339   return false;
 340 }
 341
 342 static INLINE void CheckForInvalidPointerPair(void *p1, void *p2) {
 343   switch (flags()->detect_invalid_pointer_pairs) {
 344     case 0 : return;
 345     case 1 : if (p1 == nullptr || p2 == nullptr) return; break;
 346   }
 347
 348   uptr a1 = reinterpret_cast<uptr>(p1);
 349   uptr a2 = reinterpret_cast<uptr>(p2);
 350
 351   if (IsInvalidPointerPair(a1, a2)) {
 352     GET_CALLER_PC_BP_SP;
 353     ReportInvalidPointerPair(pc, bp, sp, a1, a2);
 354   }
 355 }
 356 // ----------------------- Mac-specific reports ----------------- {{{1
 357
 358 void ReportMacMzReallocUnknown(uptr addr, uptr zone_ptr, const char *zone_name,
 359                                BufferedStackTrace *stack) {
 360   ScopedInErrorReport in_report;
 361   Printf("mz_realloc(%p) -- attempting to realloc unallocated memory.\n"
 362              "This is an unrecoverable problem, exiting now.\n",
 363              addr);
 364   PrintZoneForPointer(addr, zone_ptr, zone_name);
 365   stack->Print();
 366   DescribeAddressIfHeap(addr);
 367 }
 368
 369 // -------------- SuppressErrorReport -------------- {{{1
 370 // Avoid error reports duplicating for ASan recover mode.
 371 static bool SuppressErrorReport(uptr pc) {
 372   if (!common_flags()->suppress_equal_pcs) return false;
 373   for (unsigned i = 0; i < kAsanBuggyPcPoolSize; i++) {
 374     uptr cmp = atomic_load_relaxed(&AsanBuggyPcPool[i]);
 375     if (cmp == 0 && atomic_compare_exchange_strong(&AsanBuggyPcPool[i], &cmp,
 376                                                    pc, memory_order_relaxed))
 377       return false;
 378     if (cmp == pc) return true;
 379   }
 380   Die();
 381 }
 382
 383 void ReportGenericError(uptr pc, uptr bp, uptr sp, uptr addr, bool is_write,
 384                         uptr access_size, u32 exp, bool fatal) {
 385   if (!fatal && SuppressErrorReport(pc)) return;
 386   ENABLE_FRAME_POINTER;
 387
 388   // Optimization experiments.
 389   // The experiments can be used to evaluate potential optimizations that remove
 390   // instrumentation (assess false negatives). Instead of completely removing
 391   // some instrumentation, compiler can emit special calls into runtime
 392   // (e.g. __asan_report_exp_load1 instead of __asan_report_load1) and pass
 393   // mask of experiments (exp).
 394   // The reaction to a non-zero value of exp is to be defined.
 395   (void)exp;
 396
 397   ScopedInErrorReport in_report(fatal);
 398   ErrorGeneric error(GetCurrentTidOrInvalid(), pc, bp, sp, addr, is_write,
 399                      access_size);
 400   in_report.ReportError(error);
 401 }
 402
 403 }  // namespace __asan
 404
 405 // --------------------------- Interface --------------------- {{{1
 406 using namespace __asan;  // NOLINT
 407
 408 void __asan_report_error(uptr pc, uptr bp, uptr sp, uptr addr, int is_write,
 409                          uptr access_size, u32 exp) {
 410   ENABLE_FRAME_POINTER;
 411   bool fatal = flags()->halt_on_error;
 412   ReportGenericError(pc, bp, sp, addr, is_write, access_size, exp, fatal);
 413 }
 414
 415 void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
 416   BlockingMutexLock l(&error_message_buf_mutex);
 417   error_report_callback = callback;
 418 }
 419
 420 void __asan_describe_address(uptr addr) {
 421   // Thread registry must be locked while we're describing an address.
 422   asanThreadRegistry().Lock();
 423   PrintAddressDescription(addr, 1, "");
 424   asanThreadRegistry().Unlock();
 425 }
 426
 427 int __asan_report_present() {
 428   return ScopedInErrorReport::CurrentError().kind != kErrorKindInvalid;
 429 }
 430
 431 uptr __asan_get_report_pc() {
 432   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 433     return ScopedInErrorReport::CurrentError().Generic.pc;
 434   return 0;
 435 }
 436
 437 uptr __asan_get_report_bp() {
 438   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 439     return ScopedInErrorReport::CurrentError().Generic.bp;
 440   return 0;
 441 }
 442
 443 uptr __asan_get_report_sp() {
 444   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 445     return ScopedInErrorReport::CurrentError().Generic.sp;
 446   return 0;
 447 }
 448
 449 uptr __asan_get_report_address() {
 450   ErrorDescription &err = ScopedInErrorReport::CurrentError();
 451   if (err.kind == kErrorKindGeneric)
 452     return err.Generic.addr_description.Address();
 453   else if (err.kind == kErrorKindDoubleFree)
 454     return err.DoubleFree.addr_description.addr;
 455   return 0;
 456 }
 457
 458 int __asan_get_report_access_type() {
 459   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 460     return ScopedInErrorReport::CurrentError().Generic.is_write;
 461   return 0;
 462 }
 463
 464 uptr __asan_get_report_access_size() {
 465   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 466     return ScopedInErrorReport::CurrentError().Generic.access_size;
 467   return 0;
 468 }
 469
 470 const char *__asan_get_report_description() {
 471   if (ScopedInErrorReport::CurrentError().kind == kErrorKindGeneric)
 472     return ScopedInErrorReport::CurrentError().Generic.bug_descr;
 473   return ScopedInErrorReport::CurrentError().Base.scariness.GetDescription();
 474 }
 475
 476 extern "C" {
 477 SANITIZER_INTERFACE_ATTRIBUTE
 478 void __sanitizer_ptr_sub(void *a, void *b) {
 479   CheckForInvalidPointerPair(a, b);
 480 }
 481 SANITIZER_INTERFACE_ATTRIBUTE
 482 void __sanitizer_ptr_cmp(void *a, void *b) {
 483   CheckForInvalidPointerPair(a, b);
 484 }
 485 } // extern "C"
 486
 487 // Provide default implementation of __asan_on_error that does nothing
 488 // and may be overriden by user.
 489 SANITIZER_INTERFACE_WEAK_DEF(void, __asan_on_error, void) {}