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. 4 5 #include <fcntl.h> 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <sys/stat.h> 10 #include <sys/types.h> 11 12 #include <algorithm> 13 #include <limits> 14 15 #include "base/file_util.h" 16 #include "base/logging.h" 17 #include "base/memory/scoped_ptr.h" 18 #include "build/build_config.h" 19 #include "testing/gtest/include/gtest/gtest.h" 20 21 #if defined(OS_POSIX) 22 #include <sys/mman.h> 23 #include <unistd.h> 24 #endif 25 26 using std::nothrow; 27 using std::numeric_limits; 28 29 namespace { 30 31 // This function acts as a compiler optimization barrier. We use it to 32 // prevent the compiler from making an expression a compile-time constant. 33 // We also use it so that the compiler doesn't discard certain return values 34 // as something we don't need (see the comment with calloc below). 35 template <typename Type> 36 Type HideValueFromCompiler(volatile Type value) { 37 #if defined(__GNUC__) 38 // In a GCC compatible compiler (GCC or Clang), make this compiler barrier 39 // more robust than merely using "volatile". 40 __asm__ volatile ("" : "+r" (value)); 41 #endif // __GNUC__ 42 return value; 43 } 44 45 // - NO_TCMALLOC (should be defined if we compile with linux_use_tcmalloc=0) 46 // - ADDRESS_SANITIZER because it has its own memory allocator 47 // - IOS does not use tcmalloc 48 // - OS_MACOSX does not use tcmalloc 49 #if !defined(NO_TCMALLOC) && !defined(ADDRESS_SANITIZER) && \ 50 !defined(OS_IOS) && !defined(OS_MACOSX) 51 #define TCMALLOC_TEST(function) function 52 #else 53 #define TCMALLOC_TEST(function) DISABLED_##function 54 #endif 55 56 // TODO(jln): switch to std::numeric_limits<int>::max() when we switch to 57 // C++11. 58 const size_t kTooBigAllocSize = INT_MAX; 59 60 // Detect runtime TCMalloc bypasses. 61 bool IsTcMallocBypassed() { 62 #if defined(OS_LINUX) || defined(OS_CHROMEOS) 63 // This should detect a TCMalloc bypass from Valgrind. 64 char* g_slice = getenv("G_SLICE"); 65 if (g_slice && !strcmp(g_slice, "always-malloc")) 66 return true; 67 #elif defined(OS_WIN) 68 // This should detect a TCMalloc bypass from setting 69 // the CHROME_ALLOCATOR environment variable. 70 char* allocator = getenv("CHROME_ALLOCATOR"); 71 if (allocator && strcmp(allocator, "tcmalloc")) 72 return true; 73 #endif 74 return false; 75 } 76 77 bool CallocDiesOnOOM() { 78 // The sanitizers' calloc dies on OOM instead of returning NULL. 79 // The wrapper function in base/process_util_linux.cc that is used when we 80 // compile without TCMalloc will just die on OOM instead of returning NULL. 81 #if defined(ADDRESS_SANITIZER) || defined(MEMORY_SANITIZER) || \ 82 defined(THREAD_SANITIZER) || (defined(OS_LINUX) && defined(NO_TCMALLOC)) 83 return true; 84 #else 85 return false; 86 #endif 87 } 88 89 // Fake test that allow to know the state of TCMalloc by looking at bots. 90 TEST(SecurityTest, TCMALLOC_TEST(IsTCMallocDynamicallyBypassed)) { 91 printf("Malloc is dynamically bypassed: %s\n", 92 IsTcMallocBypassed() ? "yes." : "no."); 93 } 94 95 // The MemoryAllocationRestrictions* tests test that we can not allocate a 96 // memory range that cannot be indexed via an int. This is used to mitigate 97 // vulnerabilities in libraries that use int instead of size_t. See 98 // crbug.com/169327. 99 100 TEST(SecurityTest, TCMALLOC_TEST(MemoryAllocationRestrictionsMalloc)) { 101 if (!IsTcMallocBypassed()) { 102 scoped_ptr<char, base::FreeDeleter> ptr(static_cast<char*>( 103 HideValueFromCompiler(malloc(kTooBigAllocSize)))); 104 ASSERT_TRUE(!ptr); 105 } 106 } 107 108 TEST(SecurityTest, TCMALLOC_TEST(MemoryAllocationRestrictionsCalloc)) { 109 if (!IsTcMallocBypassed()) { 110 scoped_ptr<char, base::FreeDeleter> ptr(static_cast<char*>( 111 HideValueFromCompiler(calloc(kTooBigAllocSize, 1)))); 112 ASSERT_TRUE(!ptr); 113 } 114 } 115 116 TEST(SecurityTest, TCMALLOC_TEST(MemoryAllocationRestrictionsRealloc)) { 117 if (!IsTcMallocBypassed()) { 118 char* orig_ptr = static_cast<char*>(malloc(1)); 119 ASSERT_TRUE(orig_ptr); 120 scoped_ptr<char, base::FreeDeleter> ptr(static_cast<char*>( 121 HideValueFromCompiler(realloc(orig_ptr, kTooBigAllocSize)))); 122 ASSERT_TRUE(!ptr); 123 // If realloc() did not succeed, we need to free orig_ptr. 124 free(orig_ptr); 125 } 126 } 127 128 typedef struct { 129 char large_array[kTooBigAllocSize]; 130 } VeryLargeStruct; 131 132 TEST(SecurityTest, TCMALLOC_TEST(MemoryAllocationRestrictionsNew)) { 133 if (!IsTcMallocBypassed()) { 134 scoped_ptr<VeryLargeStruct> ptr( 135 HideValueFromCompiler(new (nothrow) VeryLargeStruct)); 136 ASSERT_TRUE(!ptr); 137 } 138 } 139 140 TEST(SecurityTest, TCMALLOC_TEST(MemoryAllocationRestrictionsNewArray)) { 141 if (!IsTcMallocBypassed()) { 142 scoped_ptr<char[]> ptr( 143 HideValueFromCompiler(new (nothrow) char[kTooBigAllocSize])); 144 ASSERT_TRUE(!ptr); 145 } 146 } 147 148 // The tests bellow check for overflows in new[] and calloc(). 149 150 #if defined(OS_IOS) || defined(OS_WIN) || defined(THREAD_SANITIZER) 151 #define DISABLE_ON_IOS_AND_WIN_AND_TSAN(function) DISABLED_##function 152 #else 153 #define DISABLE_ON_IOS_AND_WIN_AND_TSAN(function) function 154 #endif 155 156 // There are platforms where these tests are known to fail. We would like to 157 // be able to easily check the status on the bots, but marking tests as 158 // FAILS_ is too clunky. 159 void OverflowTestsSoftExpectTrue(bool overflow_detected) { 160 if (!overflow_detected) { 161 #if defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_MACOSX) 162 // Sadly, on Linux, Android, and OSX we don't have a good story yet. Don't 163 // fail the test, but report. 164 printf("Platform has overflow: %s\n", 165 !overflow_detected ? "yes." : "no."); 166 #else 167 // Otherwise, fail the test. (Note: EXPECT are ok in subfunctions, ASSERT 168 // aren't). 169 EXPECT_TRUE(overflow_detected); 170 #endif 171 } 172 } 173 174 // Test array[TooBig][X] and array[X][TooBig] allocations for int overflows. 175 // IOS doesn't honor nothrow, so disable the test there. 176 // Crashes on Windows Dbg builds, disable there as well. 177 TEST(SecurityTest, DISABLE_ON_IOS_AND_WIN_AND_TSAN(NewOverflow)) { 178 const size_t kArraySize = 4096; 179 // We want something "dynamic" here, so that the compiler doesn't 180 // immediately reject crazy arrays. 181 const size_t kDynamicArraySize = HideValueFromCompiler(kArraySize); 182 // numeric_limits are still not constexpr until we switch to C++11, so we 183 // use an ugly cast. 184 const size_t kMaxSizeT = ~static_cast<size_t>(0); 185 ASSERT_EQ(numeric_limits<size_t>::max(), kMaxSizeT); 186 const size_t kArraySize2 = kMaxSizeT / kArraySize + 10; 187 const size_t kDynamicArraySize2 = HideValueFromCompiler(kArraySize2); 188 { 189 scoped_ptr<char[][kArraySize]> array_pointer(new (nothrow) 190 char[kDynamicArraySize2][kArraySize]); 191 OverflowTestsSoftExpectTrue(!array_pointer); 192 } 193 // On windows, the compiler prevents static array sizes of more than 194 // 0x7fffffff (error C2148). 195 #if !defined(OS_WIN) || !defined(ARCH_CPU_64_BITS) 196 { 197 scoped_ptr<char[][kArraySize2]> array_pointer(new (nothrow) 198 char[kDynamicArraySize][kArraySize2]); 199 OverflowTestsSoftExpectTrue(!array_pointer); 200 } 201 #endif // !defined(OS_WIN) || !defined(ARCH_CPU_64_BITS) 202 } 203 204 // Call calloc(), eventually free the memory and return whether or not 205 // calloc() did succeed. 206 bool CallocReturnsNull(size_t nmemb, size_t size) { 207 scoped_ptr<char, base::FreeDeleter> array_pointer( 208 static_cast<char*>(calloc(nmemb, size))); 209 // We need the call to HideValueFromCompiler(): we have seen LLVM 210 // optimize away the call to calloc() entirely and assume 211 // the pointer to not be NULL. 212 return HideValueFromCompiler(array_pointer.get()) == NULL; 213 } 214 215 // Test if calloc() can overflow. 216 TEST(SecurityTest, CallocOverflow) { 217 const size_t kArraySize = 4096; 218 const size_t kMaxSizeT = numeric_limits<size_t>::max(); 219 const size_t kArraySize2 = kMaxSizeT / kArraySize + 10; 220 if (!CallocDiesOnOOM()) { 221 EXPECT_TRUE(CallocReturnsNull(kArraySize, kArraySize2)); 222 EXPECT_TRUE(CallocReturnsNull(kArraySize2, kArraySize)); 223 } else { 224 // It's also ok for calloc to just terminate the process. 225 #if defined(GTEST_HAS_DEATH_TEST) 226 EXPECT_DEATH(CallocReturnsNull(kArraySize, kArraySize2), ""); 227 EXPECT_DEATH(CallocReturnsNull(kArraySize2, kArraySize), ""); 228 #endif // GTEST_HAS_DEATH_TEST 229 } 230 } 231 232 #if (defined(OS_LINUX) || defined(OS_CHROMEOS)) && defined(__x86_64__) 233 // Check if ptr1 and ptr2 are separated by less than size chars. 234 bool ArePointersToSameArea(void* ptr1, void* ptr2, size_t size) { 235 ptrdiff_t ptr_diff = reinterpret_cast<char*>(std::max(ptr1, ptr2)) - 236 reinterpret_cast<char*>(std::min(ptr1, ptr2)); 237 return static_cast<size_t>(ptr_diff) <= size; 238 } 239 240 // Check if TCMalloc uses an underlying random memory allocator. 241 TEST(SecurityTest, TCMALLOC_TEST(RandomMemoryAllocations)) { 242 if (IsTcMallocBypassed()) 243 return; 244 size_t kPageSize = 4096; // We support x86_64 only. 245 // Check that malloc() returns an address that is neither the kernel's 246 // un-hinted mmap area, nor the current brk() area. The first malloc() may 247 // not be at a random address because TCMalloc will first exhaust any memory 248 // that it has allocated early on, before starting the sophisticated 249 // allocators. 250 void* default_mmap_heap_address = 251 mmap(0, kPageSize, PROT_READ|PROT_WRITE, 252 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 253 ASSERT_NE(default_mmap_heap_address, 254 static_cast<void*>(MAP_FAILED)); 255 ASSERT_EQ(munmap(default_mmap_heap_address, kPageSize), 0); 256 void* brk_heap_address = sbrk(0); 257 ASSERT_NE(brk_heap_address, reinterpret_cast<void*>(-1)); 258 ASSERT_TRUE(brk_heap_address != NULL); 259 // 1 MB should get us past what TCMalloc pre-allocated before initializing 260 // the sophisticated allocators. 261 size_t kAllocSize = 1<<20; 262 scoped_ptr<char, base::FreeDeleter> ptr( 263 static_cast<char*>(malloc(kAllocSize))); 264 ASSERT_TRUE(ptr != NULL); 265 // If two pointers are separated by less than 512MB, they are considered 266 // to be in the same area. 267 // Our random pointer could be anywhere within 0x3fffffffffff (46bits), 268 // and we are checking that it's not withing 1GB (30 bits) from two 269 // addresses (brk and mmap heap). We have roughly one chance out of 270 // 2^15 to flake. 271 const size_t kAreaRadius = 1<<29; 272 bool in_default_mmap_heap = ArePointersToSameArea( 273 ptr.get(), default_mmap_heap_address, kAreaRadius); 274 EXPECT_FALSE(in_default_mmap_heap); 275 276 bool in_default_brk_heap = ArePointersToSameArea( 277 ptr.get(), brk_heap_address, kAreaRadius); 278 EXPECT_FALSE(in_default_brk_heap); 279 280 // In the implementation, we always mask our random addresses with 281 // kRandomMask, so we use it as an additional detection mechanism. 282 const uintptr_t kRandomMask = 0x3fffffffffffULL; 283 bool impossible_random_address = 284 reinterpret_cast<uintptr_t>(ptr.get()) & ~kRandomMask; 285 EXPECT_FALSE(impossible_random_address); 286 } 287 288 #endif // (defined(OS_LINUX) || defined(OS_CHROMEOS)) && defined(__x86_64__) 289 290 } // namespace 291
