From b5bf9a135808b579f659d73e6048dd86bc6db903 Mon Sep 17 00:00:00 2001
From: "jln@chromium.org"
 <jln@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Tue, 15 Jan 2013 20:16:33 +0000
Subject: TCMalloc: restrict maximum size of memory allocations

For security purposes, we restrict the maximum size of memory allocations under
what can be indexed by an int.

BUG=169327
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/11857007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176961 0039d316-1c4b-4281-b951-d872f2087c98
---
 base/base.gyp             |   1 +
 base/security_unittest.cc | 103 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+)
 create mode 100644 base/security_unittest.cc

(limited to 'base')

diff --git a/base/base.gyp b/base/base.gyp
index 08cf7f4..f650f56 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -527,6 +527,7 @@
         'rand_util_unittest.cc',
         'scoped_native_library_unittest.cc',
         'scoped_observer.h',
+        'security_unittest.cc',
         'sequence_checker_unittest.cc',
         'sequence_checker_impl_unittest.cc',
         'sha1_unittest.cc',
diff --git a/base/security_unittest.cc b/base/security_unittest.cc
new file mode 100644
index 0000000..11e871b
--- /dev/null
+++ b/base/security_unittest.cc
@@ -0,0 +1,103 @@
+// 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
-- 
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