1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
11 #include <sys/types.h>
17 #include "base/allocator/buildflags.h"
18 #include "base/files/file_util.h"
19 #include "base/memory/free_deleter.h"
20 #include "base/sanitizer_buildflags.h"
21 #include "build/build_config.h"
22 #include "testing/gtest/include/gtest/gtest.h"
30 using std::numeric_limits;
34 // This function acts as a compiler optimization barrier. We use it to
35 // prevent the compiler from making an expression a compile-time constant.
36 // We also use it so that the compiler doesn't discard certain return values
37 // as something we don't need (see the comment with calloc below).
38 template <typename Type>
39 NOINLINE Type HideValueFromCompiler(volatile Type value) {
41 // In a GCC compatible compiler (GCC or Clang), make this compiler barrier
42 // more robust than merely using "volatile".
43 __asm__ volatile ("" : "+r" (value));
48 // TCmalloc, currently supported only by Linux/CrOS, supports malloc limits.
49 // - USE_TCMALLOC (should be set if compiled with use_allocator=="tcmalloc")
50 // - ADDRESS_SANITIZER it has its own memory allocator
51 #if defined(OS_LINUX) && BUILDFLAG(USE_TCMALLOC) && !defined(ADDRESS_SANITIZER)
52 #define MALLOC_OVERFLOW_TEST(function) function
54 #define MALLOC_OVERFLOW_TEST(function) DISABLED_##function
57 // There are platforms where these tests are known to fail. We would like to
58 // be able to easily check the status on the bots, but marking tests as
59 // FAILS_ is too clunky.
60 void OverflowTestsSoftExpectTrue(bool overflow_detected) {
61 if (!overflow_detected) {
62 #if defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_MACOSX)
63 // Sadly, on Linux, Android, and OSX we don't have a good story yet. Don't
64 // fail the test, but report.
65 printf("Platform has overflow: %s\n",
66 !overflow_detected ? "yes." : "no.");
68 // Otherwise, fail the test. (Note: EXPECT are ok in subfunctions, ASSERT
70 EXPECT_TRUE(overflow_detected);
75 #if defined(OS_IOS) || defined(OS_FUCHSIA) || defined(OS_MACOSX) || \
76 defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) || \
77 defined(MEMORY_SANITIZER) || BUILDFLAG(IS_HWASAN)
78 #define MAYBE_NewOverflow DISABLED_NewOverflow
80 #define MAYBE_NewOverflow NewOverflow
82 // Test array[TooBig][X] and array[X][TooBig] allocations for int
83 // overflows. IOS doesn't honor nothrow, so disable the test there.
84 // TODO(https://crbug.com/828229): Fuchsia SDK exports an incorrect
85 // new[] that gets picked up in Debug/component builds, breaking this
86 // test. Disabled on Mac for the same reason. Disabled under XSan
87 // because asan aborts when new returns nullptr,
88 // https://bugs.chromium.org/p/chromium/issues/detail?id=690271#c15
89 TEST(SecurityTest, MAYBE_NewOverflow) {
90 const size_t kArraySize = 4096;
91 // We want something "dynamic" here, so that the compiler doesn't
92 // immediately reject crazy arrays.
93 const size_t kDynamicArraySize = HideValueFromCompiler(kArraySize);
94 const size_t kMaxSizeT = std::numeric_limits<size_t>::max();
95 const size_t kArraySize2 = kMaxSizeT / kArraySize + 10;
96 const size_t kDynamicArraySize2 = HideValueFromCompiler(kArraySize2);
98 std::unique_ptr<char[][kArraySize]> array_pointer(
99 new (nothrow) char[kDynamicArraySize2][kArraySize]);
100 // Prevent clang from optimizing away the whole test.
101 char* volatile p = reinterpret_cast<char*>(array_pointer.get());
102 OverflowTestsSoftExpectTrue(!p);
104 // On windows, the compiler prevents static array sizes of more than
105 // 0x7fffffff (error C2148).
106 #if defined(OS_WIN) && defined(ARCH_CPU_64_BITS)
107 ALLOW_UNUSED_LOCAL(kDynamicArraySize);
110 std::unique_ptr<char[][kArraySize2]> array_pointer(
111 new (nothrow) char[kDynamicArraySize][kArraySize2]);
112 // Prevent clang from optimizing away the whole test.
113 char* volatile p = reinterpret_cast<char*>(array_pointer.get());
114 OverflowTestsSoftExpectTrue(!p);
116 #endif // !defined(OS_WIN) || !defined(ARCH_CPU_64_BITS)
119 #if defined(OS_LINUX) && defined(__x86_64__)
120 // Check if ptr1 and ptr2 are separated by less than size chars.
121 bool ArePointersToSameArea(void* ptr1, void* ptr2, size_t size) {
122 ptrdiff_t ptr_diff = reinterpret_cast<char*>(std::max(ptr1, ptr2)) -
123 reinterpret_cast<char*>(std::min(ptr1, ptr2));
124 return static_cast<size_t>(ptr_diff) <= size;
127 // Check if TCMalloc uses an underlying random memory allocator.
128 TEST(SecurityTest, MALLOC_OVERFLOW_TEST(RandomMemoryAllocations)) {
129 size_t kPageSize = 4096; // We support x86_64 only.
130 // Check that malloc() returns an address that is neither the kernel's
131 // un-hinted mmap area, nor the current brk() area. The first malloc() may
132 // not be at a random address because TCMalloc will first exhaust any memory
133 // that it has allocated early on, before starting the sophisticated
135 void* default_mmap_heap_address =
136 mmap(nullptr, kPageSize, PROT_READ | PROT_WRITE,
137 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
138 ASSERT_NE(default_mmap_heap_address,
139 static_cast<void*>(MAP_FAILED));
140 ASSERT_EQ(munmap(default_mmap_heap_address, kPageSize), 0);
141 void* brk_heap_address = sbrk(0);
142 ASSERT_NE(brk_heap_address, reinterpret_cast<void*>(-1));
143 ASSERT_TRUE(brk_heap_address != nullptr);
144 // 1 MB should get us past what TCMalloc pre-allocated before initializing
145 // the sophisticated allocators.
146 size_t kAllocSize = 1<<20;
147 std::unique_ptr<char, base::FreeDeleter> ptr(
148 static_cast<char*>(malloc(kAllocSize)));
149 ASSERT_TRUE(ptr != nullptr);
150 // If two pointers are separated by less than 512MB, they are considered
151 // to be in the same area.
152 // Our random pointer could be anywhere within 0x3fffffffffff (46bits),
153 // and we are checking that it's not withing 1GB (30 bits) from two
154 // addresses (brk and mmap heap). We have roughly one chance out of
156 const size_t kAreaRadius = 1<<29;
157 bool in_default_mmap_heap = ArePointersToSameArea(
158 ptr.get(), default_mmap_heap_address, kAreaRadius);
159 EXPECT_FALSE(in_default_mmap_heap);
161 bool in_default_brk_heap = ArePointersToSameArea(
162 ptr.get(), brk_heap_address, kAreaRadius);
163 EXPECT_FALSE(in_default_brk_heap);
165 // In the implementation, we always mask our random addresses with
166 // kRandomMask, so we use it as an additional detection mechanism.
167 const uintptr_t kRandomMask = 0x3fffffffffffULL;
168 bool impossible_random_address =
169 reinterpret_cast<uintptr_t>(ptr.get()) & ~kRandomMask;
170 EXPECT_FALSE(impossible_random_address);
173 #endif // defined(OS_LINUX) && defined(__x86_64__)