Add some function and URLs to induce ASan crashes.

base/debug/asan_invalid_access.cc

+// 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.
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+
+#include "base/debug/alias.h"
+#include "base/debug/asan_invalid_access.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+namespace debug {
+
+namespace {
+
+#if defined(SYZYASAN)
+// 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;
+}
+#endif
+
+}  // 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 int kArraySize = 5;
+
+void AsanHeapOverflow() {
+  scoped_ptr<int[]> array(new int[kArraySize]);
+  // Declares the dummy value as volatile to make sure it doesn't get optimized
+  // away.
+  int volatile dummy = 0;
+  dummy = array[kArraySize];
+  base::debug::Alias(const_cast<int*>(&dummy));
+}
+
+void AsanHeapUnderflow() {
+  scoped_ptr<int[]> array(new int[kArraySize]);
+  // Declares the dummy value as volatile to make sure it doesn't get optimized
+  // away.
+  int volatile dummy = 0;
+  dummy = array[-1];
+  base::debug::Alias(const_cast<int*>(&dummy));
+}
+
+void AsanHeapUseAfterFree() {
+  scoped_ptr<int[]> array(new int[kArraySize]);
+  // Declares the dummy value as volatile to make sure it doesn't get optimized
+  // away.
+  int volatile dummy = 0;
+  int* dangling = array.get();
+  array.reset();
+  dummy = dangling[kArraySize / 2];
+  base::debug::Alias(const_cast<int*>(&dummy));
+}
+
+#endif  // ADDRESS_SANITIZER || SYZYASAN
+
+#if defined(SYZYASAN)
+void AsanCorruptHeapBlock() {
+  CorruptMemoryBlock(false);
+}
+
+void AsanCorruptHeap() {
+  CorruptMemoryBlock(true);
+}
+#endif  // SYZYASAN
+
+}  // namespace debug
+}  // namespace base