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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/debug/asan_invalid_access.h"
#include <stddef.h>
#include <memory>
#include "base/debug/alias.h"
#include "base/logging.h"
#include "build/build_config.h"
#if defined(OS_WIN)
#include <windows.h>
#endif
namespace base {
namespace debug {
namespace {
#if defined(SYZYASAN) && defined(COMPILER_MSVC)
// Disable warning C4530: "C++ exception handler used, but unwind semantics are
// not enabled". We don't want to change the compilation flags just for this
// test, and no exception should be triggered here, so this warning has no value
// here.
#pragma warning(push)
#pragma warning(disable: 4530)
// Corrupt a memory block and make sure that the corruption gets detected either
// when we free it or when another crash happens (if |induce_crash| is set to
// true).
NOINLINE void CorruptMemoryBlock(bool induce_crash) {
// NOTE(sebmarchand): We intentionally corrupt a memory block here in order to
// trigger an Address Sanitizer (ASAN) error report.
static const int kArraySize = 5;
int* array = new int[kArraySize];
// Encapsulate the invalid memory access into a try-catch statement to prevent
// this function from being instrumented. This way the underflow won't be
// detected but the corruption will (as the allocator will still be hooked).
try {
// Declares the dummy value as volatile to make sure it doesn't get
// optimized away.
int volatile dummy = array[-1]--;
base::debug::Alias(const_cast<int*>(&dummy));
} catch (...) {
}
if (induce_crash)
CHECK(false);
delete[] array;
}
#pragma warning(pop)
#endif // SYZYASAN && COMPILER_MSVC
} // namespace
#if defined(ADDRESS_SANITIZER) || defined(SYZYASAN)
// NOTE(sebmarchand): We intentionally perform some invalid heap access here in
// order to trigger an AddressSanitizer (ASan) error report.
static const size_t kArraySize = 5;
void AsanHeapOverflow() {
// Declares the array as volatile to make sure it doesn't get optimized away.
std::unique_ptr<volatile int[]> array(
const_cast<volatile int*>(new int[kArraySize]));
int dummy = array[kArraySize];
base::debug::Alias(&dummy);
}
void AsanHeapUnderflow() {
// Declares the array as volatile to make sure it doesn't get optimized away.
std::unique_ptr<volatile int[]> array(
const_cast<volatile int*>(new int[kArraySize]));
// We need to store the underflow address in a temporary variable as trying to
// access array[-1] will trigger a warning C4245: "conversion from 'int' to
// 'size_t', signed/unsigned mismatch".
volatile int* underflow_address = &array[0] - 1;
int dummy = *underflow_address;
base::debug::Alias(&dummy);
}
void AsanHeapUseAfterFree() {
// Declares the array as volatile to make sure it doesn't get optimized away.
std::unique_ptr<volatile int[]> array(
const_cast<volatile int*>(new int[kArraySize]));
volatile int* dangling = array.get();
array.reset();
int dummy = dangling[kArraySize / 2];
base::debug::Alias(&dummy);
}
#endif // ADDRESS_SANITIZER || SYZYASAN
#if defined(SYZYASAN) && defined(COMPILER_MSVC)
void AsanCorruptHeapBlock() {
CorruptMemoryBlock(false);
}
void AsanCorruptHeap() {
CorruptMemoryBlock(true);
}
#endif // SYZYASAN && COMPILER_MSVC
} // namespace debug
} // namespace base
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