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//===-- ubsan_handlers_cxx.cpp --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Error logging entry points for the UBSan runtime, which are only used for C++
// compilations. This file is permitted to use language features which require
// linking against a C++ ABI library.
//
//===----------------------------------------------------------------------===//
#include "ubsan_platform.h"
#if CAN_SANITIZE_UB
#include "ubsan_handlers.h"
#include "ubsan_handlers_cxx.h"
#include "ubsan_diag.h"
#include "ubsan_type_hash.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_suppressions.h"
using namespace __sanitizer;
using namespace __ubsan;
namespace __ubsan {
extern const char *const TypeCheckKinds[];
}
// Returns true if UBSan has printed an error report.
static bool HandleDynamicTypeCacheMiss(
DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash,
ReportOptions Opts) {
if (checkDynamicType((void*)Pointer, Data->TypeInfo, Hash))
// Just a cache miss. The type matches after all.
return false;
// Check if error report should be suppressed.
DynamicTypeInfo DTI = getDynamicTypeInfoFromObject((void*)Pointer);
if (DTI.isValid() && IsVptrCheckSuppressed(DTI.getMostDerivedTypeName()))
return false;
SourceLocation Loc = Data->Loc.acquire();
ErrorType ET = ErrorType::DynamicTypeMismatch;
if (ignoreReport(Loc, Opts, ET))
return false;
ScopedReport R(Opts, Loc, ET);
Diag(Loc, DL_Error, ET,
"%0 address %1 which does not point to an object of type %2")
<< TypeCheckKinds[Data->TypeCheckKind] << (void*)Pointer << Data->Type;
// If possible, say what type it actually points to.
if (!DTI.isValid()) {
if (DTI.getOffset() < -VptrMaxOffsetToTop || DTI.getOffset() > VptrMaxOffsetToTop) {
Diag(Pointer, DL_Note, ET,
"object has a possibly invalid vptr: abs(offset to top) too big")
<< TypeName(DTI.getMostDerivedTypeName())
<< Range(Pointer, Pointer + sizeof(uptr), "possibly invalid vptr");
} else {
Diag(Pointer, DL_Note, ET, "object has invalid vptr")
<< TypeName(DTI.getMostDerivedTypeName())
<< Range(Pointer, Pointer + sizeof(uptr), "invalid vptr");
}
} else if (!DTI.getOffset())
Diag(Pointer, DL_Note, ET, "object is of type %0")
<< TypeName(DTI.getMostDerivedTypeName())
<< Range(Pointer, Pointer + sizeof(uptr), "vptr for %0");
else
// FIXME: Find the type at the specified offset, and include that
// in the note.
Diag(Pointer - DTI.getOffset(), DL_Note, ET,
"object is base class subobject at offset %0 within object of type %1")
<< DTI.getOffset() << TypeName(DTI.getMostDerivedTypeName())
<< TypeName(DTI.getSubobjectTypeName())
<< Range(Pointer, Pointer + sizeof(uptr),
"vptr for %2 base class of %1");
return true;
}
void __ubsan::__ubsan_handle_dynamic_type_cache_miss(
DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
GET_REPORT_OPTIONS(false);
HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts);
}
void __ubsan::__ubsan_handle_dynamic_type_cache_miss_abort(
DynamicTypeCacheMissData *Data, ValueHandle Pointer, ValueHandle Hash) {
// Note: -fsanitize=vptr is always recoverable.
GET_REPORT_OPTIONS(false);
if (HandleDynamicTypeCacheMiss(Data, Pointer, Hash, Opts))
Die();
}
namespace __ubsan {
void __ubsan_handle_cfi_bad_type(CFICheckFailData *Data, ValueHandle Vtable,
bool ValidVtable, ReportOptions Opts) {
SourceLocation Loc = Data->Loc.acquire();
ErrorType ET = ErrorType::CFIBadType;
if (ignoreReport(Loc, Opts, ET))
return;
ScopedReport R(Opts, Loc, ET);
DynamicTypeInfo DTI = ValidVtable
? getDynamicTypeInfoFromVtable((void *)Vtable)
: DynamicTypeInfo(0, 0, 0);
const char *CheckKindStr;
switch (Data->CheckKind) {
case CFITCK_VCall:
CheckKindStr = "virtual call";
break;
case CFITCK_NVCall:
CheckKindStr = "non-virtual call";
break;
case CFITCK_DerivedCast:
CheckKindStr = "base-to-derived cast";
break;
case CFITCK_UnrelatedCast:
CheckKindStr = "cast to unrelated type";
break;
case CFITCK_VMFCall:
CheckKindStr = "virtual pointer to member function call";
break;
case CFITCK_ICall:
case CFITCK_NVMFCall:
Die();
}
Diag(Loc, DL_Error, ET,
"control flow integrity check for type %0 failed during "
"%1 (vtable address %2)")
<< Data->Type << CheckKindStr << (void *)Vtable;
// If possible, say what type it actually points to.
if (!DTI.isValid())
Diag(Vtable, DL_Note, ET, "invalid vtable");
else
Diag(Vtable, DL_Note, ET, "vtable is of type %0")
<< TypeName(DTI.getMostDerivedTypeName());
// If the failure involved different DSOs for the check location and vtable,
// report the DSO names.
const char *DstModule = Symbolizer::GetOrInit()->GetModuleNameForPc(Vtable);
if (!DstModule)
DstModule = "(unknown)";
const char *SrcModule = Symbolizer::GetOrInit()->GetModuleNameForPc(Opts.pc);
if (!SrcModule)
SrcModule = "(unknown)";
if (internal_strcmp(SrcModule, DstModule))
Diag(Loc, DL_Note, ET, "check failed in %0, vtable located in %1")
<< SrcModule << DstModule;
}
} // namespace __ubsan
#endif // CAN_SANITIZE_UB
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