1 //===-- asan_malloc_mac.cc ------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of AddressSanitizer, an address sanity checker. 11 // 12 // Mac-specific malloc interception. 13 //===----------------------------------------------------------------------===// 14 15 #ifdef __APPLE__ 16 17 #include <AvailabilityMacros.h> 18 #include <CoreFoundation/CFBase.h> 19 #include <dlfcn.h> 20 #include <malloc/malloc.h> 21 22 #include "asan_allocator.h" 23 #include "asan_interceptors.h" 24 #include "asan_internal.h" 25 #include "asan_mac.h" 26 #include "asan_report.h" 27 #include "asan_stack.h" 28 29 // Similar code is used in Google Perftools, 30 // http://code.google.com/p/google-perftools. 31 32 // ---------------------- Replacement functions ---------------- {{{1 33 using namespace __asan; // NOLINT 34 35 // TODO(glider): do we need both zones? 36 static malloc_zone_t *system_malloc_zone = 0; 37 static malloc_zone_t *system_purgeable_zone = 0; 38 static malloc_zone_t asan_zone; 39 CFAllocatorRef cf_asan = 0; 40 41 // _CFRuntimeCreateInstance() checks whether the supplied allocator is 42 // kCFAllocatorSystemDefault and, if it is not, stores the allocator reference 43 // at the beginning of the allocated memory and returns the pointer to the 44 // allocated memory plus sizeof(CFAllocatorRef). See 45 // http://www.opensource.apple.com/source/CF/CF-635.21/CFRuntime.c 46 // Pointers returned by _CFRuntimeCreateInstance() can then be passed directly 47 // to free() or CFAllocatorDeallocate(), which leads to false invalid free 48 // reports. 49 // The corresponding rdar bug is http://openradar.appspot.com/radar?id=1796404. 50 void* ALWAYS_INLINE get_saved_cfallocator_ref(void *ptr) { 51 if (flags()->replace_cfallocator) { 52 // Make sure we're not hitting the previous page. This may be incorrect 53 // if ASan's malloc returns an address ending with 0xFF8, which will be 54 // then padded to a page boundary with a CFAllocatorRef. 55 uptr arith_ptr = (uptr)ptr; 56 if ((arith_ptr & 0xFFF) > sizeof(CFAllocatorRef)) { 57 CFAllocatorRef *saved = 58 (CFAllocatorRef*)(arith_ptr - sizeof(CFAllocatorRef)); 59 if ((*saved == cf_asan) && asan_mz_size(saved)) ptr = (void*)saved; 60 } 61 } 62 return ptr; 63 } 64 65 // The free() implementation provided by OS X calls malloc_zone_from_ptr() 66 // to find the owner of |ptr|. If the result is 0, an invalid free() is 67 // reported. Our implementation falls back to asan_free() in this case 68 // in order to print an ASan-style report. 69 // 70 // For the objects created by _CFRuntimeCreateInstance a CFAllocatorRef is 71 // placed at the beginning of the allocated chunk and the pointer returned by 72 // our allocator is off by sizeof(CFAllocatorRef). This pointer can be then 73 // passed directly to free(), which will lead to errors. 74 // To overcome this we're checking whether |ptr-sizeof(CFAllocatorRef)| 75 // contains a pointer to our CFAllocator (assuming no other allocator is used). 76 // See http://code.google.com/p/address-sanitizer/issues/detail?id=70 for more 77 // info. 78 INTERCEPTOR(void, free, void *ptr) { 79 malloc_zone_t *zone = malloc_zone_from_ptr(ptr); 80 if (zone) { 81 #if defined(MAC_OS_X_VERSION_10_6) && \ 82 MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6 83 if ((zone->version >= 6) && (zone->free_definite_size)) { 84 zone->free_definite_size(zone, ptr, malloc_size(ptr)); 85 } else { 86 malloc_zone_free(zone, ptr); 87 } 88 #else 89 malloc_zone_free(zone, ptr); 90 #endif 91 } else { 92 if (!asan_mz_size(ptr)) ptr = get_saved_cfallocator_ref(ptr); 93 GET_STACK_TRACE_HERE_FOR_FREE(ptr); 94 asan_free(ptr, &stack); 95 } 96 } 97 98 namespace __asan { 99 void ReplaceCFAllocator(); 100 } 101 102 // We can't always replace the default CFAllocator with cf_asan right in 103 // ReplaceSystemMalloc(), because it is sometimes called before 104 // __CFInitialize(), when the default allocator is invalid and replacing it may 105 // crash the program. Instead we wait for the allocator to initialize and jump 106 // in just after __CFInitialize(). Nobody is going to allocate memory using 107 // CFAllocators before that, so we won't miss anything. 108 // 109 // See http://code.google.com/p/address-sanitizer/issues/detail?id=87 110 // and http://opensource.apple.com/source/CF/CF-550.43/CFRuntime.c 111 INTERCEPTOR(void, __CFInitialize) { 112 // If the runtime is built as dynamic library, __CFInitialize wrapper may be 113 // called before __asan_init. 114 #if !MAC_INTERPOSE_FUNCTIONS 115 CHECK(flags()->replace_cfallocator); 116 CHECK(asan_inited); 117 #endif 118 REAL(__CFInitialize)(); 119 if (!cf_asan && asan_inited) ReplaceCFAllocator(); 120 } 121 122 namespace { 123 124 // TODO(glider): the mz_* functions should be united with the Linux wrappers, 125 // as they are basically copied from there. 126 size_t mz_size(malloc_zone_t* zone, const void* ptr) { 127 return asan_mz_size(ptr); 128 } 129 130 void *mz_malloc(malloc_zone_t *zone, size_t size) { 131 if (!asan_inited) { 132 CHECK(system_malloc_zone); 133 return malloc_zone_malloc(system_malloc_zone, size); 134 } 135 GET_STACK_TRACE_HERE_FOR_MALLOC; 136 return asan_malloc(size, &stack); 137 } 138 139 void *cf_malloc(CFIndex size, CFOptionFlags hint, void *info) { 140 if (!asan_inited) { 141 CHECK(system_malloc_zone); 142 return malloc_zone_malloc(system_malloc_zone, size); 143 } 144 GET_STACK_TRACE_HERE_FOR_MALLOC; 145 return asan_malloc(size, &stack); 146 } 147 148 void *mz_calloc(malloc_zone_t *zone, size_t nmemb, size_t size) { 149 if (!asan_inited) { 150 // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym. 151 const size_t kCallocPoolSize = 1024; 152 static uptr calloc_memory_for_dlsym[kCallocPoolSize]; 153 static size_t allocated; 154 size_t size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize; 155 void *mem = (void*)&calloc_memory_for_dlsym[allocated]; 156 allocated += size_in_words; 157 CHECK(allocated < kCallocPoolSize); 158 return mem; 159 } 160 GET_STACK_TRACE_HERE_FOR_MALLOC; 161 return asan_calloc(nmemb, size, &stack); 162 } 163 164 void *mz_valloc(malloc_zone_t *zone, size_t size) { 165 if (!asan_inited) { 166 CHECK(system_malloc_zone); 167 return malloc_zone_valloc(system_malloc_zone, size); 168 } 169 GET_STACK_TRACE_HERE_FOR_MALLOC; 170 return asan_memalign(kPageSize, size, &stack); 171 } 172 173 #define GET_ZONE_FOR_PTR(ptr) \ 174 malloc_zone_t *zone_ptr = malloc_zone_from_ptr(ptr); \ 175 const char *zone_name = (zone_ptr == 0) ? 0 : zone_ptr->zone_name 176 177 void ALWAYS_INLINE free_common(void *context, void *ptr) { 178 if (!ptr) return; 179 if (asan_mz_size(ptr)) { 180 GET_STACK_TRACE_HERE_FOR_FREE(ptr); 181 asan_free(ptr, &stack); 182 } else { 183 // If the pointer does not belong to any of the zones, use one of the 184 // fallback methods to free memory. 185 malloc_zone_t *zone_ptr = malloc_zone_from_ptr(ptr); 186 if (zone_ptr == system_purgeable_zone) { 187 // allocations from malloc_default_purgeable_zone() done before 188 // __asan_init() may be occasionally freed via free_common(). 189 // see http://code.google.com/p/address-sanitizer/issues/detail?id=99. 190 malloc_zone_free(zone_ptr, ptr); 191 } else { 192 // If the memory chunk pointer was moved to store additional 193 // CFAllocatorRef, fix it back. 194 ptr = get_saved_cfallocator_ref(ptr); 195 GET_STACK_TRACE_HERE_FOR_FREE(ptr); 196 if (!flags()->mac_ignore_invalid_free) { 197 asan_free(ptr, &stack); 198 } else { 199 GET_ZONE_FOR_PTR(ptr); 200 WarnMacFreeUnallocated((uptr)ptr, (uptr)zone_ptr, zone_name, &stack); 201 return; 202 } 203 } 204 } 205 } 206 207 // TODO(glider): the allocation callbacks need to be refactored. 208 void mz_free(malloc_zone_t *zone, void *ptr) { 209 free_common(zone, ptr); 210 } 211 212 void cf_free(void *ptr, void *info) { 213 free_common(info, ptr); 214 } 215 216 void *mz_realloc(malloc_zone_t *zone, void *ptr, size_t size) { 217 if (!ptr) { 218 GET_STACK_TRACE_HERE_FOR_MALLOC; 219 return asan_malloc(size, &stack); 220 } else { 221 if (asan_mz_size(ptr)) { 222 GET_STACK_TRACE_HERE_FOR_MALLOC; 223 return asan_realloc(ptr, size, &stack); 224 } else { 225 // We can't recover from reallocating an unknown address, because 226 // this would require reading at most |size| bytes from 227 // potentially unaccessible memory. 228 GET_STACK_TRACE_HERE_FOR_FREE(ptr); 229 GET_ZONE_FOR_PTR(ptr); 230 ReportMacMzReallocUnknown((uptr)ptr, (uptr)zone_ptr, zone_name, &stack); 231 } 232 } 233 } 234 235 void *cf_realloc(void *ptr, CFIndex size, CFOptionFlags hint, void *info) { 236 if (!ptr) { 237 GET_STACK_TRACE_HERE_FOR_MALLOC; 238 return asan_malloc(size, &stack); 239 } else { 240 if (asan_mz_size(ptr)) { 241 GET_STACK_TRACE_HERE_FOR_MALLOC; 242 return asan_realloc(ptr, size, &stack); 243 } else { 244 // We can't recover from reallocating an unknown address, because 245 // this would require reading at most |size| bytes from 246 // potentially unaccessible memory. 247 GET_STACK_TRACE_HERE_FOR_FREE(ptr); 248 GET_ZONE_FOR_PTR(ptr); 249 ReportMacCfReallocUnknown((uptr)ptr, (uptr)zone_ptr, zone_name, &stack); 250 } 251 } 252 } 253 254 void mz_destroy(malloc_zone_t* zone) { 255 // A no-op -- we will not be destroyed! 256 Printf("mz_destroy() called -- ignoring\n"); 257 } 258 // from AvailabilityMacros.h 259 #if defined(MAC_OS_X_VERSION_10_6) && \ 260 MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6 261 void *mz_memalign(malloc_zone_t *zone, size_t align, size_t size) { 262 if (!asan_inited) { 263 CHECK(system_malloc_zone); 264 return malloc_zone_memalign(system_malloc_zone, align, size); 265 } 266 GET_STACK_TRACE_HERE_FOR_MALLOC; 267 return asan_memalign(align, size, &stack); 268 } 269 270 // This function is currently unused, and we build with -Werror. 271 #if 0 272 void mz_free_definite_size(malloc_zone_t* zone, void *ptr, size_t size) { 273 // TODO(glider): check that |size| is valid. 274 UNIMPLEMENTED(); 275 } 276 #endif 277 #endif 278 279 // malloc_introspection callbacks. I'm not clear on what all of these do. 280 kern_return_t mi_enumerator(task_t task, void *, 281 unsigned type_mask, vm_address_t zone_address, 282 memory_reader_t reader, 283 vm_range_recorder_t recorder) { 284 // Should enumerate all the pointers we have. Seems like a lot of work. 285 return KERN_FAILURE; 286 } 287 288 size_t mi_good_size(malloc_zone_t *zone, size_t size) { 289 // I think it's always safe to return size, but we maybe could do better. 290 return size; 291 } 292 293 boolean_t mi_check(malloc_zone_t *zone) { 294 UNIMPLEMENTED(); 295 return true; 296 } 297 298 void mi_print(malloc_zone_t *zone, boolean_t verbose) { 299 UNIMPLEMENTED(); 300 return; 301 } 302 303 void mi_log(malloc_zone_t *zone, void *address) { 304 // I don't think we support anything like this 305 } 306 307 void mi_force_lock(malloc_zone_t *zone) { 308 asan_mz_force_lock(); 309 } 310 311 void mi_force_unlock(malloc_zone_t *zone) { 312 asan_mz_force_unlock(); 313 } 314 315 // This function is currently unused, and we build with -Werror. 316 #if 0 317 void mi_statistics(malloc_zone_t *zone, malloc_statistics_t *stats) { 318 // TODO(csilvers): figure out how to fill these out 319 // TODO(glider): port this from tcmalloc when ready. 320 stats->blocks_in_use = 0; 321 stats->size_in_use = 0; 322 stats->max_size_in_use = 0; 323 stats->size_allocated = 0; 324 } 325 #endif 326 327 #if defined(MAC_OS_X_VERSION_10_6) && \ 328 MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6 329 boolean_t mi_zone_locked(malloc_zone_t *zone) { 330 // UNIMPLEMENTED(); 331 return false; 332 } 333 #endif 334 335 } // unnamed namespace 336 337 extern int __CFRuntimeClassTableSize; 338 339 namespace __asan { 340 void ReplaceCFAllocator() { 341 static CFAllocatorContext asan_context = { 342 /*version*/ 0, /*info*/ &asan_zone, 343 /*retain*/ 0, /*release*/ 0, 344 /*copyDescription*/0, 345 /*allocate*/ &cf_malloc, 346 /*reallocate*/ &cf_realloc, 347 /*deallocate*/ &cf_free, 348 /*preferredSize*/ 0 }; 349 if (!cf_asan) 350 cf_asan = CFAllocatorCreate(kCFAllocatorUseContext, &asan_context); 351 if (CFAllocatorGetDefault() != cf_asan) 352 CFAllocatorSetDefault(cf_asan); 353 } 354 355 void ReplaceSystemMalloc() { 356 static malloc_introspection_t asan_introspection; 357 // Ok to use internal_memset, these places are not performance-critical. 358 internal_memset(&asan_introspection, 0, sizeof(asan_introspection)); 359 360 asan_introspection.enumerator = &mi_enumerator; 361 asan_introspection.good_size = &mi_good_size; 362 asan_introspection.check = &mi_check; 363 asan_introspection.print = &mi_print; 364 asan_introspection.log = &mi_log; 365 asan_introspection.force_lock = &mi_force_lock; 366 asan_introspection.force_unlock = &mi_force_unlock; 367 368 internal_memset(&asan_zone, 0, sizeof(malloc_zone_t)); 369 370 // Start with a version 4 zone which is used for OS X 10.4 and 10.5. 371 asan_zone.version = 4; 372 asan_zone.zone_name = "asan"; 373 asan_zone.size = &mz_size; 374 asan_zone.malloc = &mz_malloc; 375 asan_zone.calloc = &mz_calloc; 376 asan_zone.valloc = &mz_valloc; 377 asan_zone.free = &mz_free; 378 asan_zone.realloc = &mz_realloc; 379 asan_zone.destroy = &mz_destroy; 380 asan_zone.batch_malloc = 0; 381 asan_zone.batch_free = 0; 382 asan_zone.introspect = &asan_introspection; 383 384 // from AvailabilityMacros.h 385 #if defined(MAC_OS_X_VERSION_10_6) && \ 386 MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6 387 // Switch to version 6 on OSX 10.6 to support memalign. 388 asan_zone.version = 6; 389 asan_zone.free_definite_size = 0; 390 asan_zone.memalign = &mz_memalign; 391 asan_introspection.zone_locked = &mi_zone_locked; 392 393 // Request the default purgable zone to force its creation. The 394 // current default zone is registered with the purgable zone for 395 // doing tiny and small allocs. Sadly, it assumes that the default 396 // zone is the szone implementation from OS X and will crash if it 397 // isn't. By creating the zone now, this will be true and changing 398 // the default zone won't cause a problem. (OS X 10.6 and higher.) 399 system_purgeable_zone = malloc_default_purgeable_zone(); 400 #endif 401 402 // Register the ASan zone. At this point, it will not be the 403 // default zone. 404 malloc_zone_register(&asan_zone); 405 406 // Unregister and reregister the default zone. Unregistering swaps 407 // the specified zone with the last one registered which for the 408 // default zone makes the more recently registered zone the default 409 // zone. The default zone is then re-registered to ensure that 410 // allocations made from it earlier will be handled correctly. 411 // Things are not guaranteed to work that way, but it's how they work now. 412 system_malloc_zone = malloc_default_zone(); 413 malloc_zone_unregister(system_malloc_zone); 414 malloc_zone_register(system_malloc_zone); 415 // Make sure the default allocator was replaced. 416 CHECK(malloc_default_zone() == &asan_zone); 417 418 if (flags()->replace_cfallocator) { 419 // If __CFInitialize() hasn't been called yet, cf_asan will be created and 420 // installed as the default allocator after __CFInitialize() finishes (see 421 // the interceptor for __CFInitialize() above). Otherwise install cf_asan 422 // right now. On both Snow Leopard and Lion __CFInitialize() calls 423 // __CFAllocatorInitialize(), which initializes the _base._cfisa field of 424 // the default allocators we check here. 425 if (((CFRuntimeBase*)kCFAllocatorSystemDefault)->_cfisa) { 426 ReplaceCFAllocator(); 427 } 428 } 429 } 430 } // namespace __asan 431 432 #endif // __APPLE__ 433