compiler-rt/lib/ubsan/ubsan_handlers_cxx.cpp

   1 //===-- ubsan_handlers_cxx.cpp --------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Error logging entry points for the UBSan runtime, which are only used for C++
  10 // compilations. This file is permitted to use language features which require
  11 // linking against a C++ ABI library.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "ubsan_platform.h"
  16 #if CAN_SANITIZE_UB
  17 #include "ubsan_handlers.h"
  18 #include "ubsan_handlers_cxx.h"
  19 #include "ubsan_diag.h"
  20 #include "ubsan_type_hash.h"
  21
  22 #include "sanitizer_common/sanitizer_common.h"
  23 #include "sanitizer_common/sanitizer_suppressions.h"
  24
  25 using namespace __sanitizer;
  26 using namespace __ubsan;
  27
  28 namespace __ubsan {
  29   extern const char *const TypeCheckKinds[];
  30 }
  31
  32 // Returns true if UBSan has printed an error report.
  33 static bool HandleDynamicTypeCacheMiss(
  34     DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash,
  35     ReportOptions Opts) {
  36   if (checkDynamicType((void*)Pointer, Data->TypeInfo, Hash))
  37     // Just a cache miss. The type matches after all.
  38     return false;
  39
  40   // Check if error report should be suppressed.
  41   DynamicTypeInfo DTI = getDynamicTypeInfoFromObject((void*)Pointer);
  42   if (DTI.isValid() && IsVptrCheckSuppressed(DTI.getMostDerivedTypeName()))
  43     return false;
  44
  45   SourceLocation Loc = Data->Loc.acquire();
  46   ErrorType ET = ErrorType::DynamicTypeMismatch;
  47   if (ignoreReport(Loc, Opts, ET))
  48     return false;
  49
  50   ScopedReport R(Opts, Loc, ET);
  51
  52   Diag(Loc, DL_Error, ET,
  53        "%0 address %1 which does not point to an object of type %2")
  54     << TypeCheckKinds[Data->TypeCheckKind] << (void*)Pointer << Data->Type;
  55
  56   // If possible, say what type it actually points to.
  57   if (!DTI.isValid()) {
  58     if (DTI.getOffset() < -VptrMaxOffsetToTop || DTI.getOffset() > VptrMaxOffsetToTop) {
  59       Diag(Pointer, DL_Note, ET,
  60            "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, ET, "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, ET, "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, ET,
  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 __ubsan_handle_cfi_bad_type(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_VMFCall:
 126     CheckKindStr = "virtual pointer to member function call";
 127     break;
 128   case CFITCK_ICall:
 129   case CFITCK_NVMFCall:
 130     Die();
 131   }
 132
 133   Diag(Loc, DL_Error, ET,
 134        "control flow integrity check for type %0 failed during "
 135        "%1 (vtable address %2)")
 136       << Data->Type << CheckKindStr << (void *)Vtable;
 137
 138   // If possible, say what type it actually points to.
 139   if (!DTI.isValid())
 140     Diag(Vtable, DL_Note, ET, "invalid vtable");
 141   else
 142     Diag(Vtable, DL_Note, ET, "vtable is of type %0")
 143         << TypeName(DTI.getMostDerivedTypeName());
 144
 145   // If the failure involved different DSOs for the check location and vtable,
 146   // report the DSO names.
 147   const char *DstModule = Symbolizer::GetOrInit()->GetModuleNameForPc(Vtable);
 148   if (!DstModule)
 149     DstModule = "(unknown)";
 150
 151   const char *SrcModule = Symbolizer::GetOrInit()->GetModuleNameForPc(Opts.pc);
 152   if (!SrcModule)
 153     SrcModule = "(unknown)";
 154
 155   if (internal_strcmp(SrcModule, DstModule))
 156     Diag(Loc, DL_Note, ET, "check failed in %0, vtable located in %1")
 157         << SrcModule << DstModule;
 158 }
 159 }  // namespace __ubsan
 160
 161 #endif // CAN_SANITIZE_UB