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) || defined(OS_CHROMEOS)) && BUILDFLAG(USE_TCMALLOC) && \
52 !defined(ADDRESS_SANITIZER)
53 #define MALLOC_OVERFLOW_TEST(function) function
55 #define MALLOC_OVERFLOW_TEST(function) DISABLED_##function
58 // There are platforms where these tests are known to fail. We would like to
59 // be able to easily check the status on the bots, but marking tests as
60 // FAILS_ is too clunky.
61 void OverflowTestsSoftExpectTrue(bool overflow_detected) {
62 if (!overflow_detected) {
63 #if defined(OS_LINUX) || defined(OS_CHROMEOS) || defined(OS_ANDROID) || \
65 // Sadly, on Linux, Android, and OSX we don't have a good story yet. Don't
66 // fail the test, but report.
67 printf("Platform has overflow: %s\n",
68 !overflow_detected ? "yes." : "no.");
70 // Otherwise, fail the test. (Note: EXPECT are ok in subfunctions, ASSERT
72 EXPECT_TRUE(overflow_detected);
77 #if defined(OS_FUCHSIA) || defined(OS_APPLE) || defined(ADDRESS_SANITIZER) || \
78 defined(THREAD_SANITIZER) || defined(MEMORY_SANITIZER) || \
79 BUILDFLAG(IS_HWASAN) || BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
80 #define MAYBE_NewOverflow DISABLED_NewOverflow
82 #define MAYBE_NewOverflow NewOverflow
84 // Test that array[TooBig][X] and array[X][TooBig] allocations fail and not
85 // succeed with the wrong size allocation in case of size_t overflow. This
86 // test is disabled on environments that operator new (nothrow) crashes in
87 // case of size_t overflow.
89 // - iOS doesn't honor nothrow.
90 // - XSan aborts when operator new returns nullptr.
91 // - PartitionAlloc crashes by design when size_t overflows.
93 // TODO(https://crbug.com/828229): Fuchsia SDK exports an incorrect
94 // new[] that gets picked up in Debug/component builds, breaking this
95 // test. Disabled on Mac for the same reason.
96 TEST(SecurityTest, MAYBE_NewOverflow) {
97 const size_t kArraySize = 4096;
98 // We want something "dynamic" here, so that the compiler doesn't
99 // immediately reject crazy arrays.
100 const size_t kDynamicArraySize = HideValueFromCompiler(kArraySize);
101 const size_t kMaxSizeT = std::numeric_limits<size_t>::max();
102 const size_t kArraySize2 = kMaxSizeT / kArraySize + 10;
103 const size_t kDynamicArraySize2 = HideValueFromCompiler(kArraySize2);
105 std::unique_ptr<char[][kArraySize]> array_pointer(
106 new (nothrow) char[kDynamicArraySize2][kArraySize]);
107 // Prevent clang from optimizing away the whole test.
108 char* volatile p = reinterpret_cast<char*>(array_pointer.get());
109 OverflowTestsSoftExpectTrue(!p);
111 // On windows, the compiler prevents static array sizes of more than
112 // 0x7fffffff (error C2148).
113 #if defined(OS_WIN) && defined(ARCH_CPU_64_BITS)
114 ALLOW_UNUSED_LOCAL(kDynamicArraySize);
117 std::unique_ptr<char[][kArraySize2]> array_pointer(
118 new (nothrow) char[kDynamicArraySize][kArraySize2]);
119 // Prevent clang from optimizing away the whole test.
120 char* volatile p = reinterpret_cast<char*>(array_pointer.get());
121 OverflowTestsSoftExpectTrue(!p);
123 #endif // !defined(OS_WIN) || !defined(ARCH_CPU_64_BITS)
126 #if (defined(OS_LINUX) || defined(OS_CHROMEOS)) && defined(__x86_64__)
127 // Check if ptr1 and ptr2 are separated by less than size chars.
128 bool ArePointersToSameArea(void* ptr1, void* ptr2, size_t size) {
129 ptrdiff_t ptr_diff = reinterpret_cast<char*>(std::max(ptr1, ptr2)) -
130 reinterpret_cast<char*>(std::min(ptr1, ptr2));
131 return static_cast<size_t>(ptr_diff) <= size;
134 // Check if TCMalloc uses an underlying random memory allocator.
135 TEST(SecurityTest, MALLOC_OVERFLOW_TEST(RandomMemoryAllocations)) {
136 size_t kPageSize = 4096; // We support x86_64 only.
137 // Check that malloc() returns an address that is neither the kernel's
138 // un-hinted mmap area, nor the current brk() area. The first malloc() may
139 // not be at a random address because TCMalloc will first exhaust any memory
140 // that it has allocated early on, before starting the sophisticated
142 void* default_mmap_heap_address =
143 mmap(nullptr, kPageSize, PROT_READ | PROT_WRITE,
144 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
145 ASSERT_NE(default_mmap_heap_address,
146 static_cast<void*>(MAP_FAILED));
147 ASSERT_EQ(munmap(default_mmap_heap_address, kPageSize), 0);
148 void* brk_heap_address = sbrk(0);
149 ASSERT_NE(brk_heap_address, reinterpret_cast<void*>(-1));
150 ASSERT_TRUE(brk_heap_address != nullptr);
151 // 1 MB should get us past what TCMalloc pre-allocated before initializing
152 // the sophisticated allocators.
153 size_t kAllocSize = 1<<20;
154 std::unique_ptr<char, base::FreeDeleter> ptr(
155 static_cast<char*>(malloc(kAllocSize)));
156 ASSERT_TRUE(ptr != nullptr);
157 // If two pointers are separated by less than 512MB, they are considered
158 // to be in the same area.
159 // Our random pointer could be anywhere within 0x3fffffffffff (46bits),
160 // and we are checking that it's not withing 1GB (30 bits) from two
161 // addresses (brk and mmap heap). We have roughly one chance out of
163 const size_t kAreaRadius = 1<<29;
164 bool in_default_mmap_heap = ArePointersToSameArea(
165 ptr.get(), default_mmap_heap_address, kAreaRadius);
166 EXPECT_FALSE(in_default_mmap_heap);
168 bool in_default_brk_heap = ArePointersToSameArea(
169 ptr.get(), brk_heap_address, kAreaRadius);
170 EXPECT_FALSE(in_default_brk_heap);
172 // In the implementation, we always mask our random addresses with
173 // kRandomMask, so we use it as an additional detection mechanism.
174 const uintptr_t kRandomMask = 0x3fffffffffffULL;
175 bool impossible_random_address =
176 reinterpret_cast<uintptr_t>(ptr.get()) & ~kRandomMask;
177 EXPECT_FALSE(impossible_random_address);
180 #endif // (defined(OS_LINUX) || defined(OS_CHROMEOS)) && defined(__x86_64__)