libsanitizer/asan/asan_mac.cc

   1 //===-- asan_mac.cc -------------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Mac-specific details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifdef __APPLE__
  14
  15 #include "asan_interceptors.h"
  16 #include "asan_internal.h"
  17 #include "asan_mac.h"
  18 #include "asan_mapping.h"
  19 #include "asan_stack.h"
  20 #include "asan_thread.h"
  21 #include "asan_thread_registry.h"
  22 #include "sanitizer_common/sanitizer_libc.h"
  23
  24 #include <crt_externs.h>  // for _NSGetArgv
  25 #include <dlfcn.h>  // for dladdr()
  26 #include <mach-o/dyld.h>
  27 #include <mach-o/loader.h>
  28 #include <sys/mman.h>
  29 #include <sys/resource.h>
  30 #include <sys/sysctl.h>
  31 #include <sys/ucontext.h>
  32 #include <fcntl.h>
  33 #include <pthread.h>
  34 #include <stdlib.h>  // for free()
  35 #include <unistd.h>
  36 #include <libkern/OSAtomic.h>
  37 #include <CoreFoundation/CFString.h>
  38
  39 namespace __asan {
  40
  41 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
  42   ucontext_t *ucontext = (ucontext_t*)context;
  43 # if SANITIZER_WORDSIZE == 64
  44   *pc = ucontext->uc_mcontext->__ss.__rip;
  45   *bp = ucontext->uc_mcontext->__ss.__rbp;
  46   *sp = ucontext->uc_mcontext->__ss.__rsp;
  47 # else
  48   *pc = ucontext->uc_mcontext->__ss.__eip;
  49   *bp = ucontext->uc_mcontext->__ss.__ebp;
  50   *sp = ucontext->uc_mcontext->__ss.__esp;
  51 # endif  // SANITIZER_WORDSIZE
  52 }
  53
  54 int GetMacosVersion() {
  55   int mib[2] = { CTL_KERN, KERN_OSRELEASE };
  56   char version[100];
  57   uptr len = 0, maxlen = sizeof(version) / sizeof(version[0]);
  58   for (uptr i = 0; i < maxlen; i++) version[i] = '\0';
  59   // Get the version length.
  60   CHECK(sysctl(mib, 2, 0, &len, 0, 0) != -1);
  61   CHECK(len < maxlen);
  62   CHECK(sysctl(mib, 2, version, &len, 0, 0) != -1);
  63   switch (version[0]) {
  64     case '9': return MACOS_VERSION_LEOPARD;
  65     case '1': {
  66       switch (version[1]) {
  67         case '0': return MACOS_VERSION_SNOW_LEOPARD;
  68         case '1': return MACOS_VERSION_LION;
  69         case '2': return MACOS_VERSION_MOUNTAIN_LION;
  70         default: return MACOS_VERSION_UNKNOWN;
  71       }
  72     }
  73     default: return MACOS_VERSION_UNKNOWN;
  74   }
  75 }
  76
  77 bool PlatformHasDifferentMemcpyAndMemmove() {
  78   // On OS X 10.7 memcpy() and memmove() are both resolved
  79   // into memmove$VARIANT$sse42.
  80   // See also http://code.google.com/p/address-sanitizer/issues/detail?id=34.
  81   // TODO(glider): need to check dynamically that memcpy() and memmove() are
  82   // actually the same function.
  83   return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD;
  84 }
  85
  86 extern "C"
  87 void __asan_init();
  88
  89 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
  90
  91 void MaybeReexec() {
  92   if (!flags()->allow_reexec) return;
  93 #if MAC_INTERPOSE_FUNCTIONS
  94   // If the program is linked with the dynamic ASan runtime library, make sure
  95   // the library is preloaded so that the wrappers work. If it is not, set
  96   // DYLD_INSERT_LIBRARIES and re-exec ourselves.
  97   Dl_info info;
  98   CHECK(dladdr((void*)((uptr)__asan_init), &info));
  99   const char *dyld_insert_libraries = GetEnv(kDyldInsertLibraries);
 100   if (!dyld_insert_libraries ||
 101       !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) {
 102     // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime
 103     // library.
 104     char program_name[1024];
 105     uint32_t buf_size = sizeof(program_name);
 106     _NSGetExecutablePath(program_name, &buf_size);
 107     // Ok to use setenv() since the wrappers don't depend on the value of
 108     // asan_inited.
 109     setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0);
 110     if (flags()->verbosity >= 1) {
 111       Report("exec()-ing the program with\n");
 112       Report("%s=%s\n", kDyldInsertLibraries, info.dli_fname);
 113       Report("to enable ASan wrappers.\n");
 114       Report("Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n");
 115     }
 116     execv(program_name, *_NSGetArgv());
 117   }
 118 #endif  // MAC_INTERPOSE_FUNCTIONS
 119   // If we're not using the dynamic runtime, do nothing.
 120 }
 121
 122 // No-op. Mac does not support static linkage anyway.
 123 void *AsanDoesNotSupportStaticLinkage() {
 124   return 0;
 125 }
 126
 127 bool AsanInterceptsSignal(int signum) {
 128   return (signum == SIGSEGV || signum == SIGBUS) && flags()->handle_segv;
 129 }
 130
 131 void AsanPlatformThreadInit() {
 132   // For the first program thread, we can't replace the allocator before
 133   // __CFInitialize() has been called. If it hasn't, we'll call
 134   // MaybeReplaceCFAllocator() later on this thread.
 135   // For other threads __CFInitialize() has been called before their creation.
 136   // See also asan_malloc_mac.cc.
 137   if (((CFRuntimeBase*)kCFAllocatorSystemDefault)->_cfisa) {
 138     MaybeReplaceCFAllocator();
 139   }
 140 }
 141
 142 AsanLock::AsanLock(LinkerInitialized) {
 143   // We assume that OS_SPINLOCK_INIT is zero
 144 }
 145
 146 void AsanLock::Lock() {
 147   CHECK(sizeof(OSSpinLock) <= sizeof(opaque_storage_));
 148   CHECK(OS_SPINLOCK_INIT == 0);
 149   CHECK(owner_ != (uptr)pthread_self());
 150   OSSpinLockLock((OSSpinLock*)&opaque_storage_);
 151   CHECK(!owner_);
 152   owner_ = (uptr)pthread_self();
 153 }
 154
 155 void AsanLock::Unlock() {
 156   CHECK(owner_ == (uptr)pthread_self());
 157   owner_ = 0;
 158   OSSpinLockUnlock((OSSpinLock*)&opaque_storage_);
 159 }
 160
 161 void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp) {
 162   stack->size = 0;
 163   stack->trace[0] = pc;
 164   if ((max_s) > 1) {
 165     stack->max_size = max_s;
 166     if (!asan_inited) return;
 167     if (AsanThread *t = asanThreadRegistry().GetCurrent())
 168       stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom());
 169   }
 170 }
 171
 172 void ClearShadowMemoryForContext(void *context) {
 173   UNIMPLEMENTED();
 174 }
 175
 176 // The range of pages to be used for escape islands.
 177 // TODO(glider): instead of mapping a fixed range we must find a range of
 178 // unmapped pages in vmmap and take them.
 179 // These constants were chosen empirically and may not work if the shadow
 180 // memory layout changes. Unfortunately they do necessarily depend on
 181 // kHighMemBeg or kHighMemEnd.
 182 static void *island_allocator_pos = 0;
 183
 184 #if SANITIZER_WORDSIZE == 32
 185 # define kIslandEnd (0xffdf0000 - kPageSize)
 186 # define kIslandBeg (kIslandEnd - 256 * kPageSize)
 187 #else
 188 # define kIslandEnd (0x7fffffdf0000 - kPageSize)
 189 # define kIslandBeg (kIslandEnd - 256 * kPageSize)
 190 #endif
 191
 192 extern "C"
 193 mach_error_t __interception_allocate_island(void **ptr,
 194                                             uptr unused_size,
 195                                             void *unused_hint) {
 196   if (!island_allocator_pos) {
 197     island_allocator_pos =
 198         internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg,
 199                       PROT_READ | PROT_WRITE | PROT_EXEC,
 200                       MAP_PRIVATE | MAP_ANON | MAP_FIXED,
 201                       -1, 0);
 202     if (island_allocator_pos != (void*)kIslandBeg) {
 203       return KERN_NO_SPACE;
 204     }
 205     if (flags()->verbosity) {
 206       Report("Mapped pages %p--%p for branch islands.\n",
 207              (void*)kIslandBeg, (void*)kIslandEnd);
 208     }
 209     // Should not be very performance-critical.
 210     internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg);
 211   };
 212   *ptr = island_allocator_pos;
 213   island_allocator_pos = (char*)island_allocator_pos + kPageSize;
 214   if (flags()->verbosity) {
 215     Report("Branch island allocated at %p\n", *ptr);
 216   }
 217   return err_none;
 218 }
 219
 220 extern "C"
 221 mach_error_t __interception_deallocate_island(void *ptr) {
 222   // Do nothing.
 223   // TODO(glider): allow to free and reuse the island memory.
 224   return err_none;
 225 }
 226
 227 // Support for the following functions from libdispatch on Mac OS:
 228 //   dispatch_async_f()
 229 //   dispatch_async()
 230 //   dispatch_sync_f()
 231 //   dispatch_sync()
 232 //   dispatch_after_f()
 233 //   dispatch_after()
 234 //   dispatch_group_async_f()
 235 //   dispatch_group_async()
 236 // TODO(glider): libdispatch API contains other functions that we don't support
 237 // yet.
 238 //
 239 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 240 // they can cause jobs to run on a thread different from the current one.
 241 // TODO(glider): if so, we need a test for this (otherwise we should remove
 242 // them).
 243 //
 244 // The following functions use dispatch_barrier_async_f() (which isn't a library
 245 // function but is exported) and are thus supported:
 246 //   dispatch_source_set_cancel_handler_f()
 247 //   dispatch_source_set_cancel_handler()
 248 //   dispatch_source_set_event_handler_f()
 249 //   dispatch_source_set_event_handler()
 250 //
 251 // The reference manual for Grand Central Dispatch is available at
 252 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 253 // The implementation details are at
 254 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 255
 256 typedef void* pthread_workqueue_t;
 257 typedef void* pthread_workitem_handle_t;
 258
 259 typedef void* dispatch_group_t;
 260 typedef void* dispatch_queue_t;
 261 typedef void* dispatch_source_t;
 262 typedef u64 dispatch_time_t;
 263 typedef void (*dispatch_function_t)(void *block);
 264 typedef void* (*worker_t)(void *block);
 265
 266 // A wrapper for the ObjC blocks used to support libdispatch.
 267 typedef struct {
 268   void *block;
 269   dispatch_function_t func;
 270   u32 parent_tid;
 271 } asan_block_context_t;
 272
 273 // We use extern declarations of libdispatch functions here instead
 274 // of including <dispatch/dispatch.h>. This header is not present on
 275 // Mac OS X Leopard and eariler, and although we don't expect ASan to
 276 // work on legacy systems, it's bad to break the build of
 277 // LLVM compiler-rt there.
 278 extern "C" {
 279 void dispatch_async_f(dispatch_queue_t dq, void *ctxt,
 280                       dispatch_function_t func);
 281 void dispatch_sync_f(dispatch_queue_t dq, void *ctxt,
 282                      dispatch_function_t func);
 283 void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt,
 284                       dispatch_function_t func);
 285 void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt,
 286                               dispatch_function_t func);
 287 void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq,
 288                             void *ctxt, dispatch_function_t func);
 289 int pthread_workqueue_additem_np(pthread_workqueue_t workq,
 290     void *(*workitem_func)(void *), void * workitem_arg,
 291     pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp);
 292 }  // extern "C"
 293
 294 static ALWAYS_INLINE
 295 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 296   AsanThread *t = asanThreadRegistry().GetCurrent();
 297   if (!t) {
 298     t = AsanThread::Create(parent_tid, 0, 0, stack);
 299     asanThreadRegistry().RegisterThread(t);
 300     t->Init();
 301     asanThreadRegistry().SetCurrent(t);
 302   }
 303 }
 304
 305 // For use by only those functions that allocated the context via
 306 // alloc_asan_context().
 307 extern "C"
 308 void asan_dispatch_call_block_and_release(void *block) {
 309   GET_STACK_TRACE_HERE(kStackTraceMax);
 310   asan_block_context_t *context = (asan_block_context_t*)block;
 311   if (flags()->verbosity >= 2) {
 312     Report("asan_dispatch_call_block_and_release(): "
 313            "context: %p, pthread_self: %p\n",
 314            block, pthread_self());
 315   }
 316   asan_register_worker_thread(context->parent_tid, &stack);
 317   // Call the original dispatcher for the block.
 318   context->func(context->block);
 319   asan_free(context, &stack);
 320 }
 321
 322 }  // namespace __asan
 323
 324 using namespace __asan;  // NOLINT
 325
 326 // Wrap |ctxt| and |func| into an asan_block_context_t.
 327 // The caller retains control of the allocated context.
 328 extern "C"
 329 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 330                                          StackTrace *stack) {
 331   asan_block_context_t *asan_ctxt =
 332       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 333   asan_ctxt->block = ctxt;
 334   asan_ctxt->func = func;
 335   asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid();
 336   return asan_ctxt;
 337 }
 338
 339 // Define interceptor for dispatch_*_f function with the three most common
 340 // parameters: dispatch_queue_t, context, dispatch_function_t.
 341 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 342   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 343                                   dispatch_function_t func) {                 \
 344     GET_STACK_TRACE_HERE(kStackTraceMax);                                     \
 345     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 346     if (flags()->verbosity >= 2) {                                            \
 347       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 348              asan_ctxt, pthread_self());                                      \
 349        PRINT_CURRENT_STACK();                                                 \
 350      }                                                                        \
 351      return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                          \
 352                                asan_dispatch_call_block_and_release);         \
 353   }
 354
 355 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 356 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 357 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 358
 359 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 360                                     dispatch_queue_t dq, void *ctxt,
 361                                     dispatch_function_t func) {
 362   GET_STACK_TRACE_HERE(kStackTraceMax);
 363   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 364   if (flags()->verbosity >= 2) {
 365     Report("dispatch_after_f: %p\n", asan_ctxt);
 366     PRINT_CURRENT_STACK();
 367   }
 368   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 369                                 asan_dispatch_call_block_and_release);
 370 }
 371
 372 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 373                                           dispatch_queue_t dq, void *ctxt,
 374                                           dispatch_function_t func) {
 375   GET_STACK_TRACE_HERE(kStackTraceMax);
 376   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 377   if (flags()->verbosity >= 2) {
 378     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 379            asan_ctxt, pthread_self());
 380     PRINT_CURRENT_STACK();
 381   }
 382   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 383                                asan_dispatch_call_block_and_release);
 384 }
 385
 386 #if MAC_INTERPOSE_FUNCTIONS
 387 // dispatch_async, dispatch_group_async and others tailcall the corresponding
 388 // dispatch_*_f functions. When wrapping functions with mach_override, those
 389 // dispatch_*_f are intercepted automatically. But with dylib interposition
 390 // this does not work, because the calls within the same library are not
 391 // interposed.
 392 // Therefore we need to re-implement dispatch_async and friends.
 393
 394 extern "C" {
 395 // FIXME: consolidate these declarations with asan_intercepted_functions.h.
 396 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 397 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 398                           void(^work)(void));
 399 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 400                     void(^work)(void));
 401 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 402                                         void(^work)(void));
 403 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 404 }
 405
 406 #define GET_ASAN_BLOCK(work) \
 407   void (^asan_block)(void);  \
 408   int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \
 409   asan_block = ^(void) { \
 410     GET_STACK_TRACE_HERE(kStackTraceMax); \
 411     asan_register_worker_thread(parent_tid, &stack); \
 412     work(); \
 413   }
 414
 415 INTERCEPTOR(void, dispatch_async,
 416             dispatch_queue_t dq, void(^work)(void)) {
 417   GET_ASAN_BLOCK(work);
 418   REAL(dispatch_async)(dq, asan_block);
 419 }
 420
 421 INTERCEPTOR(void, dispatch_group_async,
 422             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 423   GET_ASAN_BLOCK(work);
 424   REAL(dispatch_group_async)(dg, dq, asan_block);
 425 }
 426
 427 INTERCEPTOR(void, dispatch_after,
 428             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 429   GET_ASAN_BLOCK(work);
 430   REAL(dispatch_after)(when, queue, asan_block);
 431 }
 432
 433 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 434             dispatch_source_t ds, void(^work)(void)) {
 435   GET_ASAN_BLOCK(work);
 436   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 437 }
 438
 439 INTERCEPTOR(void, dispatch_source_set_event_handler,
 440             dispatch_source_t ds, void(^work)(void)) {
 441   GET_ASAN_BLOCK(work);
 442   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 443 }
 444 #endif
 445
 446 // The following stuff has been extremely helpful while looking for the
 447 // unhandled functions that spawned jobs on Chromium shutdown. If the verbosity
 448 // level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to
 449 // find the points of worker thread creation (each of such threads may be used
 450 // to run several tasks, that's why this is not enough to support the whole
 451 // libdispatch API.
 452 extern "C"
 453 void *wrap_workitem_func(void *arg) {
 454   if (flags()->verbosity >= 2) {
 455     Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self());
 456   }
 457   asan_block_context_t *ctxt = (asan_block_context_t*)arg;
 458   worker_t fn = (worker_t)(ctxt->func);
 459   void *result =  fn(ctxt->block);
 460   GET_STACK_TRACE_HERE(kStackTraceMax);
 461   asan_free(arg, &stack);
 462   return result;
 463 }
 464
 465 INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq,
 466     void *(*workitem_func)(void *), void * workitem_arg,
 467     pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) {
 468   GET_STACK_TRACE_HERE(kStackTraceMax);
 469   asan_block_context_t *asan_ctxt =
 470       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack);
 471   asan_ctxt->block = workitem_arg;
 472   asan_ctxt->func = (dispatch_function_t)workitem_func;
 473   asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid();
 474   if (flags()->verbosity >= 2) {
 475     Report("pthread_workqueue_additem_np: %p\n", asan_ctxt);
 476     PRINT_CURRENT_STACK();
 477   }
 478   return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func,
 479                                             asan_ctxt, itemhandlep,
 480                                             gencountp);
 481 }
 482
 483 // See http://opensource.apple.com/source/CF/CF-635.15/CFString.c
 484 int __CFStrIsConstant(CFStringRef str) {
 485   CFRuntimeBase *base = (CFRuntimeBase*)str;
 486 #if __LP64__
 487   return base->_rc == 0;
 488 #else
 489   return (base->_cfinfo[CF_RC_BITS]) == 0;
 490 #endif
 491 }
 492
 493 INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc,
 494                                              CFStringRef str) {
 495   if (__CFStrIsConstant(str)) {
 496     return str;
 497   } else {
 498     return REAL(CFStringCreateCopy)(alloc, str);
 499   }
 500 }
 501
 502 DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr)
 503
 504 DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize, void)
 505
 506 namespace __asan {
 507
 508 void InitializeMacInterceptors() {
 509   CHECK(INTERCEPT_FUNCTION(dispatch_async_f));
 510   CHECK(INTERCEPT_FUNCTION(dispatch_sync_f));
 511   CHECK(INTERCEPT_FUNCTION(dispatch_after_f));
 512   CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f));
 513   CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f));
 514   // We don't need to intercept pthread_workqueue_additem_np() to support the
 515   // libdispatch API, but it helps us to debug the unsupported functions. Let's
 516   // intercept it only during verbose runs.
 517   if (flags()->verbosity >= 2) {
 518     CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np));
 519   }
 520   // Normally CFStringCreateCopy should not copy constant CF strings.
 521   // Replacing the default CFAllocator causes constant strings to be copied
 522   // rather than just returned, which leads to bugs in big applications like
 523   // Chromium and WebKit, see
 524   // http://code.google.com/p/address-sanitizer/issues/detail?id=10
 525   // Until this problem is fixed we need to check that the string is
 526   // non-constant before calling CFStringCreateCopy.
 527   CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy));
 528   // Some of the library functions call free() directly, so we have to
 529   // intercept it.
 530   CHECK(INTERCEPT_FUNCTION(free));
 531   if (flags()->replace_cfallocator) {
 532     CHECK(INTERCEPT_FUNCTION(__CFInitialize));
 533   }
 534 }
 535
 536 }  // namespace __asan
 537
 538 #endif  // __APPLE__