libsanitizer/ubsan/ubsan_handlers_cxx.cc

   1 //===-- ubsan_handlers_cxx.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 // Error logging entry points for the UBSan runtime, which are only used for C++
   9 // compilations. This file is permitted to use language features which require
  10 // linking against a C++ ABI library.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "ubsan_platform.h"
  15 #if CAN_SANITIZE_UB
  16 #include "ubsan_handlers.h"
  17 #include "ubsan_handlers_cxx.h"
  18 #include "ubsan_diag.h"
  19 #include "ubsan_type_hash.h"
  20
  21 #include "sanitizer_common/sanitizer_common.h"
  22 #include "sanitizer_common/sanitizer_suppressions.h"
  23
  24 using namespace __sanitizer;
  25 using namespace __ubsan;
  26
  27 namespace __ubsan {
  28   extern const char *TypeCheckKinds[];
  29 }
  30
  31 // Returns true if UBSan has printed an error report.
  32 static bool HandleDynamicTypeCacheMiss(
  33     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash,
  34     ReportOptions Opts) {
  35   if (checkDynamicType((void*)Pointer, Data->TypeInfo, Hash))
  36     // Just a cache miss. The type matches after all.
  37     return false;
  38
  39   // Check if error report should be suppressed.
  40   DynamicTypeInfo DTI = getDynamicTypeInfoFromObject((void*)Pointer);
  41   if (DTI.isValid() && IsVptrCheckSuppressed(DTI.getMostDerivedTypeName()))
  42     return false;
  43
  44   SourceLocation Loc = Data->Loc.acquire();
  45   ErrorType ET = ErrorType::DynamicTypeMismatch;
  46   if (ignoreReport(Loc, Opts, ET))
  47     return false;
  48
  49   ScopedReport R(Opts, Loc, ET);
  50
  51   Diag(Loc, DL_Error,
  52        "%0 address %1 which does not point to an object of type %2")
  53     << TypeCheckKinds[Data->TypeCheckKind] << (void*)Pointer << Data->Type;
  54
  55   // If possible, say what type it actually points to.
  56   if (!DTI.isValid()) {
  57     if (DTI.getOffset() < -VptrMaxOffsetToTop || DTI.getOffset() > VptrMaxOffsetToTop) {
  58       Diag(Pointer, DL_Note, "object has a possibly invalid vptr: abs(offset to top) too big")
  59           << TypeName(DTI.getMostDerivedTypeName())
  60           << Range(Pointer, Pointer + sizeof(uptr), "possibly invalid vptr");
  61     } else {
  62       Diag(Pointer, DL_Note, "object has invalid vptr")
  63           << TypeName(DTI.getMostDerivedTypeName())
  64           << Range(Pointer, Pointer + sizeof(uptr), "invalid vptr");
  65     }
  66   } else if (!DTI.getOffset())
  67     Diag(Pointer, DL_Note, "object is of type %0")
  68         << TypeName(DTI.getMostDerivedTypeName())
  69         << Range(Pointer, Pointer + sizeof(uptr), "vptr for %0");
  70   else
  71     // FIXME: Find the type at the specified offset, and include that
  72     //        in the note.
  73     Diag(Pointer - DTI.getOffset(), DL_Note,
  74          "object is base class subobject at offset %0 within object of type %1")
  75         << DTI.getOffset() << TypeName(DTI.getMostDerivedTypeName())
  76         << TypeName(DTI.getSubobjectTypeName())
  77         << Range(Pointer, Pointer + sizeof(uptr),
  78                  "vptr for %2 base class of %1");
  79   return true;
  80 }
  81
  82 void __ubsan::__ubsan_handle_dynamic_type_cache_miss(
  83     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
  84   GET_REPORT_OPTIONS(false);
  85   HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts);
  86 }
  87 void __ubsan::__ubsan_handle_dynamic_type_cache_miss_abort(
  88     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
  89   // Note: -fsanitize=vptr is always recoverable.
  90   GET_REPORT_OPTIONS(false);
  91   if (HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts))
  92     Die();
  93 }
  94
  95 namespace __ubsan {
  96 void __ubsan_handle_cfi_bad_type(CFICheckFailData *Data, ValueHandle Vtable,
  97                                  bool ValidVtable, ReportOptions Opts) {
  98   SourceLocation Loc = Data->Loc.acquire();
  99   ErrorType ET = ErrorType::CFIBadType;
 100
 101   if (ignoreReport(Loc, Opts, ET))
 102     return;
 103
 104   ScopedReport R(Opts, Loc, ET);
 105   DynamicTypeInfo DTI = ValidVtable
 106                             ? getDynamicTypeInfoFromVtable((void *)Vtable)
 107                             : DynamicTypeInfo(0, 0, 0);
 108
 109   const char *CheckKindStr;
 110   switch (Data->CheckKind) {
 111   case CFITCK_VCall:
 112     CheckKindStr = "virtual call";
 113     break;
 114   case CFITCK_NVCall:
 115     CheckKindStr = "non-virtual call";
 116     break;
 117   case CFITCK_DerivedCast:
 118     CheckKindStr = "base-to-derived cast";
 119     break;
 120   case CFITCK_UnrelatedCast:
 121     CheckKindStr = "cast to unrelated type";
 122     break;
 123   case CFITCK_ICall:
 124   default:
 125     Die();
 126   }
 127
 128   Diag(Loc, DL_Error, "control flow integrity check for type %0 failed during "
 129                       "%1 (vtable address %2)")
 130       << Data->Type << CheckKindStr << (void *)Vtable;
 131
 132   // If possible, say what type it actually points to.
 133   if (!DTI.isValid()) {
 134     const char *module = Symbolizer::GetOrInit()->GetModuleNameForPc(Vtable);
 135     if (module)
 136       Diag(Vtable, DL_Note, "invalid vtable in module %0") << module;
 137     else
 138       Diag(Vtable, DL_Note, "invalid vtable");
 139   } else {
 140     Diag(Vtable, DL_Note, "vtable is of type %0")
 141         << TypeName(DTI.getMostDerivedTypeName());
 142   }
 143 }
 144 }  // namespace __ubsan
 145
 146 #endif // CAN_SANITIZE_UB