TCMalloc: restrict maximum size of memory ranges

base/security_unittest.cc

+// Copyright (c) 2013 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <algorithm>
+#include <limits>
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using std::nothrow;
+
+namespace {
+
+// Check that we can not allocate a memory range that cannot be indexed
+// via an int. This is used to mitigate vulnerabilities in libraries that use
+// int instead of size_t.
+// See crbug.com/169327.
+
+// - NO_TCMALLOC because we only patched tcmalloc
+// - ADDRESS_SANITIZER because it has its own memory allocator
+// - IOS does not seem to honor nothrow in new properly
+// - OS_MACOSX does not use tcmalloc
+#if !defined(NO_TCMALLOC) && !defined(ADDRESS_SANITIZER) && \
+    !defined(OS_IOS) && !defined(OS_MACOSX)
+  #define ALLOC_TEST(function) function
+#else
+  #define ALLOC_TEST(function) DISABLED_##function
+#endif
+
+// TODO(jln): switch to std::numeric_limits<int>::max() when we switch to
+// C++11.
+const size_t kTooBigAllocSize = INT_MAX;
+
+// Detect runtime TCMalloc bypasses.
+bool IsTcMallocBypassed() {
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
+  // This should detect a TCMalloc bypass from Valgrind.
+  char* g_slice = getenv("G_SLICE");
+  if (g_slice && !strcmp(g_slice, "always-malloc"))
+    return true;
+#endif
+  return false;
+}
+
+// Fake test that allow to know the state of TCMalloc by looking at bots.
+TEST(SecurityTest, ALLOC_TEST(IsTCMallocDynamicallyBypassed)) {
+  printf("Malloc is dynamically bypassed: %s\n",
+         IsTcMallocBypassed() ? "yes." : "no.");
+}
+
+TEST(SecurityTest, ALLOC_TEST(MemoryAllocationRestrictionsMalloc)) {
+  if (!IsTcMallocBypassed()) {
+    scoped_ptr<char, base::FreeDeleter>
+        ptr(static_cast<char*>(malloc(kTooBigAllocSize)));
+    ASSERT_TRUE(ptr == NULL);
+  }
+}
+
+TEST(SecurityTest, ALLOC_TEST(MemoryAllocationRestrictionsCalloc)) {
+  if (!IsTcMallocBypassed()) {
+    scoped_ptr<char, base::FreeDeleter>
+        ptr(static_cast<char*>(calloc(kTooBigAllocSize, 1)));
+    ASSERT_TRUE(ptr == NULL);
+  }
+}
+
+TEST(SecurityTest, ALLOC_TEST(MemoryAllocationRestrictionsRealloc)) {
+  if (!IsTcMallocBypassed()) {
+    char* orig_ptr = static_cast<char*>(malloc(1));
+    ASSERT_TRUE(orig_ptr != NULL);
+    scoped_ptr<char, base::FreeDeleter>
+        ptr(static_cast<char*>(realloc(orig_ptr, kTooBigAllocSize)));
+    ASSERT_TRUE(ptr == NULL);
+    // If realloc() did not succeed, we need to free orig_ptr.
+    free(orig_ptr);
+  }
+}
+
+typedef struct {
+  char large_array[kTooBigAllocSize];
+} VeryLargeStruct;
+
+TEST(SecurityTest, ALLOC_TEST(MemoryAllocationRestrictionsNew)) {
+  if (!IsTcMallocBypassed()) {
+    scoped_ptr<VeryLargeStruct> ptr(new (nothrow) VeryLargeStruct);
+    ASSERT_TRUE(ptr == NULL);
+  }
+}
+
+TEST(SecurityTest, ALLOC_TEST(MemoryAllocationRestrictionsNewArray)) {
+  if (!IsTcMallocBypassed()) {
+    scoped_array<char> ptr(new (nothrow) char[kTooBigAllocSize]);
+    ASSERT_TRUE(ptr == NULL);
+  }
+}
+
+}  // namespace