src/libcompiler_builtins/compiler-rt/lib/ubsan/ubsan_handlers_cxx.cc

   1 //===-- ubsan_handlers_cxx.cc ---------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Error logging entry points for the UBSan runtime, which are only used for C++
  11 // compilations. This file is permitted to use language features which require
  12 // linking against a C++ ABI library.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "ubsan_platform.h"
  17 #if CAN_SANITIZE_UB
  18 #include "ubsan_handlers.h"
  19 #include "ubsan_handlers_cxx.h"
  20 #include "ubsan_diag.h"
  21 #include "ubsan_type_hash.h"
  22
  23 #include "sanitizer_common/sanitizer_common.h"
  24 #include "sanitizer_common/sanitizer_suppressions.h"
  25
  26 using namespace __sanitizer;
  27 using namespace __ubsan;
  28
  29 namespace __ubsan {
  30   extern const char *TypeCheckKinds[];
  31 }
  32
  33 // Returns true if UBSan has printed an error report.
  34 static bool HandleDynamicTypeCacheMiss(
  35     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash,
  36     ReportOptions Opts) {
  37   if (checkDynamicType((void*)Pointer, Data->TypeInfo, Hash))
  38     // Just a cache miss. The type matches after all.
  39     return false;
  40
  41   // Check if error report should be suppressed.
  42   DynamicTypeInfo DTI = getDynamicTypeInfoFromObject((void*)Pointer);
  43   if (DTI.isValid() && IsVptrCheckSuppressed(DTI.getMostDerivedTypeName()))
  44     return false;
  45
  46   SourceLocation Loc = Data->Loc.acquire();
  47   ErrorType ET = ErrorType::DynamicTypeMismatch;
  48   if (ignoreReport(Loc, Opts, ET))
  49     return false;
  50
  51   ScopedReport R(Opts, Loc, ET);
  52
  53   Diag(Loc, DL_Error,
  54        "%0 address %1 which does not point to an object of type %2")
  55     << TypeCheckKinds[Data->TypeCheckKind] << (void*)Pointer << Data->Type;
  56
  57   // If possible, say what type it actually points to.
  58   if (!DTI.isValid()) {
  59     if (DTI.getOffset() < -VptrMaxOffsetToTop || DTI.getOffset() > VptrMaxOffsetToTop) {
  60       Diag(Pointer, DL_Note, "object has a possibly invalid vptr: abs(offset to top) too big")
  61           << TypeName(DTI.getMostDerivedTypeName())
  62           << Range(Pointer, Pointer + sizeof(uptr), "possibly invalid vptr");
  63     } else {
  64       Diag(Pointer, DL_Note, "object has invalid vptr")
  65           << TypeName(DTI.getMostDerivedTypeName())
  66           << Range(Pointer, Pointer + sizeof(uptr), "invalid vptr");
  67     }
  68   } else if (!DTI.getOffset())
  69     Diag(Pointer, DL_Note, "object is of type %0")
  70         << TypeName(DTI.getMostDerivedTypeName())
  71         << Range(Pointer, Pointer + sizeof(uptr), "vptr for %0");
  72   else
  73     // FIXME: Find the type at the specified offset, and include that
  74     //        in the note.
  75     Diag(Pointer - DTI.getOffset(), DL_Note,
  76          "object is base class subobject at offset %0 within object of type %1")
  77         << DTI.getOffset() << TypeName(DTI.getMostDerivedTypeName())
  78         << TypeName(DTI.getSubobjectTypeName())
  79         << Range(Pointer, Pointer + sizeof(uptr),
  80                  "vptr for %2 base class of %1");
  81   return true;
  82 }
  83
  84 void __ubsan::__ubsan_handle_dynamic_type_cache_miss(
  85     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
  86   GET_REPORT_OPTIONS(false);
  87   HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts);
  88 }
  89 void __ubsan::__ubsan_handle_dynamic_type_cache_miss_abort(
  90     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
  91   // Note: -fsanitize=vptr is always recoverable.
  92   GET_REPORT_OPTIONS(false);
  93   if (HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts))
  94     Die();
  95 }
  96
  97 namespace __ubsan {
  98 void HandleCFIBadType(CFICheckFailData *Data, ValueHandle Vtable,
  99                       bool ValidVtable, ReportOptions Opts) {
 100   SourceLocation Loc = Data->Loc.acquire();
 101   ErrorType ET = ErrorType::CFIBadType;
 102
 103   if (ignoreReport(Loc, Opts, ET))
 104     return;
 105
 106   ScopedReport R(Opts, Loc, ET);
 107   DynamicTypeInfo DTI = ValidVtable
 108                             ? getDynamicTypeInfoFromVtable((void *)Vtable)
 109                             : DynamicTypeInfo(0, 0, 0);
 110
 111   const char *CheckKindStr;
 112   switch (Data->CheckKind) {
 113   case CFITCK_VCall:
 114     CheckKindStr = "virtual call";
 115     break;
 116   case CFITCK_NVCall:
 117     CheckKindStr = "non-virtual call";
 118     break;
 119   case CFITCK_DerivedCast:
 120     CheckKindStr = "base-to-derived cast";
 121     break;
 122   case CFITCK_UnrelatedCast:
 123     CheckKindStr = "cast to unrelated type";
 124     break;
 125   case CFITCK_ICall:
 126     Die();
 127   }
 128
 129   Diag(Loc, DL_Error, "control flow integrity check for type %0 failed during "
 130                       "%1 (vtable address %2)")
 131       << Data->Type << CheckKindStr << (void *)Vtable;
 132
 133   // If possible, say what type it actually points to.
 134   if (!DTI.isValid()) {
 135     const char *module = Symbolizer::GetOrInit()->GetModuleNameForPc(Vtable);
 136     if (module)
 137       Diag(Vtable, DL_Note, "invalid vtable in module %0") << module;
 138     else
 139       Diag(Vtable, DL_Note, "invalid vtable");
 140   } else {
 141     Diag(Vtable, DL_Note, "vtable is of type %0")
 142         << TypeName(DTI.getMostDerivedTypeName());
 143   }
 144 }
 145 }  // namespace __ubsan
 146
 147 #endif // CAN_SANITIZE_UB