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| 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 "base/process/memory.h" | |
| 6 | |
| 7 #include <new> | |
| 8 | |
| 9 #include "base/files/file_path.h" | |
| 10 #include "base/files/file_util.h" | |
| 11 #include "base/logging.h" | |
| 12 #include "base/process/internal_linux.h" | |
| 13 #include "base/strings/string_number_conversions.h" | |
| 14 | |
| 15 #if defined(USE_TCMALLOC) | |
| 16 // Used by UncheckedMalloc. If tcmalloc is linked to the executable | |
| 17 // this will be replaced by a strong symbol that actually implement | |
| 18 // the semantics and don't call new handler in case the allocation fails. | |
| 19 extern "C" { | |
| 20 | |
| 21 __attribute__((weak, visibility("default"))) | |
| 22 void* tc_malloc_skip_new_handler_weak(size_t size); | |
| 23 | |
| 24 void* tc_malloc_skip_new_handler_weak(size_t size) { | |
| 25 return malloc(size); | |
| 26 } | |
| 27 | |
| 28 } | |
| 29 #endif | |
| 30 | |
| 31 namespace base { | |
| 32 | |
| 33 size_t g_oom_size = 0U; | |
| 34 | |
| 35 namespace { | |
| 36 | |
| 37 #if !defined(OS_ANDROID) | |
| 38 void OnNoMemorySize(size_t size) { | |
| 39 g_oom_size = size; | |
| 40 | |
| 41 if (size != 0) | |
| 42 LOG(FATAL) << "Out of memory, size = " << size; | |
| 43 LOG(FATAL) << "Out of memory."; | |
| 44 } | |
| 45 | |
| 46 void OnNoMemory() { | |
| 47 OnNoMemorySize(0); | |
| 48 } | |
| 49 #endif // !defined(OS_ANDROID) | |
| 50 | |
| 51 } // namespace | |
| 52 | |
| 53 #if !defined(ADDRESS_SANITIZER) && !defined(MEMORY_SANITIZER) && \ | |
| 54 !defined(THREAD_SANITIZER) && !defined(LEAK_SANITIZER) | |
| 55 | |
| 56 #if defined(LIBC_GLIBC) && !defined(USE_TCMALLOC) | |
| 57 | |
| 58 extern "C" { | |
| 59 void* __libc_malloc(size_t size); | |
| 60 void* __libc_realloc(void* ptr, size_t size); | |
| 61 void* __libc_calloc(size_t nmemb, size_t size); | |
| 62 void* __libc_valloc(size_t size); | |
| 63 #if PVALLOC_AVAILABLE == 1 | |
| 64 void* __libc_pvalloc(size_t size); | |
| 65 #endif | |
| 66 void* __libc_memalign(size_t alignment, size_t size); | |
| 67 | |
| 68 // Overriding the system memory allocation functions: | |
| 69 // | |
| 70 // For security reasons, we want malloc failures to be fatal. Too much code | |
| 71 // doesn't check for a NULL return value from malloc and unconditionally uses | |
| 72 // the resulting pointer. If the first offset that they try to access is | |
| 73 // attacker controlled, then the attacker can direct the code to access any | |
| 74 // part of memory. | |
| 75 // | |
| 76 // Thus, we define all the standard malloc functions here and mark them as | |
| 77 // visibility 'default'. This means that they replace the malloc functions for | |
| 78 // all Chromium code and also for all code in shared libraries. There are tests | |
| 79 // for this in process_util_unittest.cc. | |
| 80 // | |
| 81 // If we are using tcmalloc, then the problem is moot since tcmalloc handles | |
| 82 // this for us. Thus this code is in a !defined(USE_TCMALLOC) block. | |
| 83 // | |
| 84 // If we are testing the binary with AddressSanitizer, we should not | |
| 85 // redefine malloc and let AddressSanitizer do it instead. | |
| 86 // | |
| 87 // We call the real libc functions in this code by using __libc_malloc etc. | |
| 88 // Previously we tried using dlsym(RTLD_NEXT, ...) but that failed depending on | |
| 89 // the link order. Since ld.so needs calloc during symbol resolution, it | |
| 90 // defines its own versions of several of these functions in dl-minimal.c. | |
| 91 // Depending on the runtime library order, dlsym ended up giving us those | |
| 92 // functions and bad things happened. See crbug.com/31809 | |
| 93 // | |
| 94 // This means that any code which calls __libc_* gets the raw libc versions of | |
| 95 // these functions. | |
| 96 | |
| 97 #define DIE_ON_OOM_1(function_name) \ | |
| 98 void* function_name(size_t) __attribute__ ((visibility("default"))); \ | |
| 99 \ | |
| 100 void* function_name(size_t size) { \ | |
| 101 void* ret = __libc_##function_name(size); \ | |
| 102 if (ret == NULL && size != 0) \ | |
| 103 OnNoMemorySize(size); \ | |
| 104 return ret; \ | |
| 105 } | |
| 106 | |
| 107 #define DIE_ON_OOM_2(function_name, arg1_type) \ | |
| 108 void* function_name(arg1_type, size_t) \ | |
| 109 __attribute__ ((visibility("default"))); \ | |
| 110 \ | |
| 111 void* function_name(arg1_type arg1, size_t size) { \ | |
| 112 void* ret = __libc_##function_name(arg1, size); \ | |
| 113 if (ret == NULL && size != 0) \ | |
| 114 OnNoMemorySize(size); \ | |
| 115 return ret; \ | |
| 116 } | |
| 117 | |
| 118 DIE_ON_OOM_1(malloc) | |
| 119 DIE_ON_OOM_1(valloc) | |
| 120 #if PVALLOC_AVAILABLE == 1 | |
| 121 DIE_ON_OOM_1(pvalloc) | |
| 122 #endif | |
| 123 | |
| 124 DIE_ON_OOM_2(calloc, size_t) | |
| 125 DIE_ON_OOM_2(realloc, void*) | |
| 126 DIE_ON_OOM_2(memalign, size_t) | |
| 127 | |
| 128 // posix_memalign has a unique signature and doesn't have a __libc_ variant. | |
| 129 int posix_memalign(void** ptr, size_t alignment, size_t size) | |
| 130 __attribute__ ((visibility("default"))); | |
| 131 | |
| 132 int posix_memalign(void** ptr, size_t alignment, size_t size) { | |
| 133 // This will use the safe version of memalign, above. | |
| 134 *ptr = memalign(alignment, size); | |
| 135 return 0; | |
| 136 } | |
| 137 | |
| 138 } // extern C | |
| 139 | |
| 140 #else | |
| 141 | |
| 142 // TODO(mostynb@opera.com): dlsym dance | |
| 143 | |
| 144 #endif // LIBC_GLIBC && !USE_TCMALLOC | |
| 145 | |
| 146 #endif // !*_SANITIZER | |
| 147 | |
| 148 void EnableTerminationOnHeapCorruption() { | |
| 149 // On Linux, there nothing to do AFAIK. | |
| 150 } | |
| 151 | |
| 152 void EnableTerminationOnOutOfMemory() { | |
| 153 #if defined(OS_ANDROID) | |
| 154 // Android doesn't support setting a new handler. | |
| 155 DLOG(WARNING) << "Not feasible."; | |
| 156 #else | |
| 157 // Set the new-out of memory handler. | |
| 158 std::set_new_handler(&OnNoMemory); | |
| 159 // If we're using glibc's allocator, the above functions will override | |
| 160 // malloc and friends and make them die on out of memory. | |
| 161 #endif | |
| 162 } | |
| 163 | |
| 164 // NOTE: This is not the only version of this function in the source: | |
| 165 // the setuid sandbox (in process_util_linux.c, in the sandbox source) | |
| 166 // also has its own C version. | |
| 167 bool AdjustOOMScore(ProcessId process, int score) { | |
| 168 if (score < 0 || score > kMaxOomScore) | |
| 169 return false; | |
| 170 | |
| 171 FilePath oom_path(internal::GetProcPidDir(process)); | |
| 172 | |
| 173 // Attempt to write the newer oom_score_adj file first. | |
| 174 FilePath oom_file = oom_path.AppendASCII("oom_score_adj"); | |
| 175 if (PathExists(oom_file)) { | |
| 176 std::string score_str = IntToString(score); | |
| 177 DVLOG(1) << "Adjusting oom_score_adj of " << process << " to " | |
| 178 << score_str; | |
| 179 int score_len = static_cast<int>(score_str.length()); | |
| 180 return (score_len == WriteFile(oom_file, score_str.c_str(), score_len)); | |
| 181 } | |
| 182 | |
| 183 // If the oom_score_adj file doesn't exist, then we write the old | |
| 184 // style file and translate the oom_adj score to the range 0-15. | |
| 185 oom_file = oom_path.AppendASCII("oom_adj"); | |
| 186 if (PathExists(oom_file)) { | |
| 187 // Max score for the old oom_adj range. Used for conversion of new | |
| 188 // values to old values. | |
| 189 const int kMaxOldOomScore = 15; | |
| 190 | |
| 191 int converted_score = score * kMaxOldOomScore / kMaxOomScore; | |
| 192 std::string score_str = IntToString(converted_score); | |
| 193 DVLOG(1) << "Adjusting oom_adj of " << process << " to " << score_str; | |
| 194 int score_len = static_cast<int>(score_str.length()); | |
| 195 return (score_len == WriteFile(oom_file, score_str.c_str(), score_len)); | |
| 196 } | |
| 197 | |
| 198 return false; | |
| 199 } | |
| 200 | |
| 201 bool UncheckedMalloc(size_t size, void** result) { | |
| 202 #if defined(MEMORY_TOOL_REPLACES_ALLOCATOR) || \ | |
| 203 (!defined(LIBC_GLIBC) && !defined(USE_TCMALLOC)) | |
| 204 *result = malloc(size); | |
| 205 #elif defined(LIBC_GLIBC) && !defined(USE_TCMALLOC) | |
| 206 *result = __libc_malloc(size); | |
| 207 #elif defined(USE_TCMALLOC) | |
| 208 *result = tc_malloc_skip_new_handler_weak(size); | |
| 209 #endif | |
| 210 return *result != NULL; | |
| 211 } | |
| 212 | |
| 213 } // namespace base | |
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