asan_mac.cc revision fe6d91684bcda766593800f6307233f1a33d31f6
1//===-- asan_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 details. 13//===----------------------------------------------------------------------===// 14 15#ifdef __APPLE__ 16 17#include "asan_interceptors.h" 18#include "asan_internal.h" 19#include "asan_mac.h" 20#include "asan_mapping.h" 21#include "asan_stack.h" 22#include "asan_thread.h" 23#include "asan_thread_registry.h" 24#include "sanitizer_common/sanitizer_libc.h" 25 26#include <crt_externs.h> // for _NSGetArgv 27#include <dlfcn.h> // for dladdr() 28#include <mach-o/dyld.h> 29#include <mach-o/loader.h> 30#include <sys/mman.h> 31#include <sys/resource.h> 32#include <sys/sysctl.h> 33#include <sys/ucontext.h> 34#include <fcntl.h> 35#include <pthread.h> 36#include <stdlib.h> // for free() 37#include <unistd.h> 38#include <libkern/OSAtomic.h> 39#include <CoreFoundation/CFString.h> 40 41namespace __asan { 42 43void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) { 44 ucontext_t *ucontext = (ucontext_t*)context; 45# if SANITIZER_WORDSIZE == 64 46 *pc = ucontext->uc_mcontext->__ss.__rip; 47 *bp = ucontext->uc_mcontext->__ss.__rbp; 48 *sp = ucontext->uc_mcontext->__ss.__rsp; 49# else 50 *pc = ucontext->uc_mcontext->__ss.__eip; 51 *bp = ucontext->uc_mcontext->__ss.__ebp; 52 *sp = ucontext->uc_mcontext->__ss.__esp; 53# endif // SANITIZER_WORDSIZE 54} 55 56int GetMacosVersion() { 57 int mib[2] = { CTL_KERN, KERN_OSRELEASE }; 58 char version[100]; 59 uptr len = 0, maxlen = sizeof(version) / sizeof(version[0]); 60 for (uptr i = 0; i < maxlen; i++) version[i] = '\0'; 61 // Get the version length. 62 CHECK(sysctl(mib, 2, 0, &len, 0, 0) != -1); 63 CHECK(len < maxlen); 64 CHECK(sysctl(mib, 2, version, &len, 0, 0) != -1); 65 switch (version[0]) { 66 case '9': return MACOS_VERSION_LEOPARD; 67 case '1': { 68 switch (version[1]) { 69 case '0': return MACOS_VERSION_SNOW_LEOPARD; 70 case '1': return MACOS_VERSION_LION; 71 case '2': return MACOS_VERSION_MOUNTAIN_LION; 72 default: return MACOS_VERSION_UNKNOWN; 73 } 74 } 75 default: return MACOS_VERSION_UNKNOWN; 76 } 77} 78 79bool PlatformHasDifferentMemcpyAndMemmove() { 80 // On OS X 10.7 memcpy() and memmove() are both resolved 81 // into memmove$VARIANT$sse42. 82 // See also http://code.google.com/p/address-sanitizer/issues/detail?id=34. 83 // TODO(glider): need to check dynamically that memcpy() and memmove() are 84 // actually the same function. 85 return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD; 86} 87 88extern "C" 89void __asan_init(); 90 91static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES"; 92 93void MaybeReexec() { 94 if (!flags()->allow_reexec) return; 95#if MAC_INTERPOSE_FUNCTIONS 96 // If the program is linked with the dynamic ASan runtime library, make sure 97 // the library is preloaded so that the wrappers work. If it is not, set 98 // DYLD_INSERT_LIBRARIES and re-exec ourselves. 99 Dl_info info; 100 CHECK(dladdr((void*)((uptr)__asan_init), &info)); 101 const char *dyld_insert_libraries = GetEnv(kDyldInsertLibraries); 102 if (!dyld_insert_libraries || 103 !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) { 104 // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime 105 // library. 106 char program_name[1024]; 107 uint32_t buf_size = sizeof(program_name); 108 _NSGetExecutablePath(program_name, &buf_size); 109 // Ok to use setenv() since the wrappers don't depend on the value of 110 // asan_inited. 111 setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0); 112 if (flags()->verbosity >= 1) { 113 Report("exec()-ing the program with\n"); 114 Report("%s=%s\n", kDyldInsertLibraries, info.dli_fname); 115 Report("to enable ASan wrappers.\n"); 116 Report("Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n"); 117 } 118 execv(program_name, *_NSGetArgv()); 119 } 120#endif // MAC_INTERPOSE_FUNCTIONS 121 // If we're not using the dynamic runtime, do nothing. 122} 123 124// No-op. Mac does not support static linkage anyway. 125void *AsanDoesNotSupportStaticLinkage() { 126 return 0; 127} 128 129bool AsanInterceptsSignal(int signum) { 130 return (signum == SIGSEGV || signum == SIGBUS) && flags()->handle_segv; 131} 132 133void AsanPlatformThreadInit() { 134 // For the first program thread, we can't replace the allocator before 135 // __CFInitialize() has been called. If it hasn't, we'll call 136 // MaybeReplaceCFAllocator() later on this thread. 137 // For other threads __CFInitialize() has been called before their creation. 138 // See also asan_malloc_mac.cc. 139 if (((CFRuntimeBase*)kCFAllocatorSystemDefault)->_cfisa) { 140 MaybeReplaceCFAllocator(); 141 } 142} 143 144AsanLock::AsanLock(LinkerInitialized) { 145 // We assume that OS_SPINLOCK_INIT is zero 146} 147 148void AsanLock::Lock() { 149 CHECK(sizeof(OSSpinLock) <= sizeof(opaque_storage_)); 150 CHECK(OS_SPINLOCK_INIT == 0); 151 CHECK(owner_ != (uptr)pthread_self()); 152 OSSpinLockLock((OSSpinLock*)&opaque_storage_); 153 CHECK(!owner_); 154 owner_ = (uptr)pthread_self(); 155} 156 157void AsanLock::Unlock() { 158 CHECK(owner_ == (uptr)pthread_self()); 159 owner_ = 0; 160 OSSpinLockUnlock((OSSpinLock*)&opaque_storage_); 161} 162 163void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, bool fast) { 164 (void)fast; 165 stack->size = 0; 166 stack->trace[0] = pc; 167 if ((max_s) > 1) { 168 stack->max_size = max_s; 169 if (!asan_inited) return; 170 if (AsanThread *t = asanThreadRegistry().GetCurrent()) 171 stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom()); 172 } 173} 174 175void ClearShadowMemoryForContext(void *context) { 176 UNIMPLEMENTED(); 177} 178 179// The range of pages to be used for escape islands. 180// TODO(glider): instead of mapping a fixed range we must find a range of 181// unmapped pages in vmmap and take them. 182// These constants were chosen empirically and may not work if the shadow 183// memory layout changes. Unfortunately they do necessarily depend on 184// kHighMemBeg or kHighMemEnd. 185static void *island_allocator_pos = 0; 186 187#if SANITIZER_WORDSIZE == 32 188# define kIslandEnd (0xffdf0000 - GetPageSizeCached()) 189# define kIslandBeg (kIslandEnd - 256 * GetPageSizeCached()) 190#else 191# define kIslandEnd (0x7fffffdf0000 - GetPageSizeCached()) 192# define kIslandBeg (kIslandEnd - 256 * GetPageSizeCached()) 193#endif 194 195extern "C" 196mach_error_t __interception_allocate_island(void **ptr, 197 uptr unused_size, 198 void *unused_hint) { 199 if (!island_allocator_pos) { 200 island_allocator_pos = 201 internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg, 202 PROT_READ | PROT_WRITE | PROT_EXEC, 203 MAP_PRIVATE | MAP_ANON | MAP_FIXED, 204 -1, 0); 205 if (island_allocator_pos != (void*)kIslandBeg) { 206 return KERN_NO_SPACE; 207 } 208 if (flags()->verbosity) { 209 Report("Mapped pages %p--%p for branch islands.\n", 210 (void*)kIslandBeg, (void*)kIslandEnd); 211 } 212 // Should not be very performance-critical. 213 internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg); 214 }; 215 *ptr = island_allocator_pos; 216 island_allocator_pos = (char*)island_allocator_pos + GetPageSizeCached(); 217 if (flags()->verbosity) { 218 Report("Branch island allocated at %p\n", *ptr); 219 } 220 return err_none; 221} 222 223extern "C" 224mach_error_t __interception_deallocate_island(void *ptr) { 225 // Do nothing. 226 // TODO(glider): allow to free and reuse the island memory. 227 return err_none; 228} 229 230// Support for the following functions from libdispatch on Mac OS: 231// dispatch_async_f() 232// dispatch_async() 233// dispatch_sync_f() 234// dispatch_sync() 235// dispatch_after_f() 236// dispatch_after() 237// dispatch_group_async_f() 238// dispatch_group_async() 239// TODO(glider): libdispatch API contains other functions that we don't support 240// yet. 241// 242// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 243// they can cause jobs to run on a thread different from the current one. 244// TODO(glider): if so, we need a test for this (otherwise we should remove 245// them). 246// 247// The following functions use dispatch_barrier_async_f() (which isn't a library 248// function but is exported) and are thus supported: 249// dispatch_source_set_cancel_handler_f() 250// dispatch_source_set_cancel_handler() 251// dispatch_source_set_event_handler_f() 252// dispatch_source_set_event_handler() 253// 254// The reference manual for Grand Central Dispatch is available at 255// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 256// The implementation details are at 257// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 258 259typedef void* pthread_workqueue_t; 260typedef void* pthread_workitem_handle_t; 261 262typedef void* dispatch_group_t; 263typedef void* dispatch_queue_t; 264typedef void* dispatch_source_t; 265typedef u64 dispatch_time_t; 266typedef void (*dispatch_function_t)(void *block); 267typedef void* (*worker_t)(void *block); 268 269// A wrapper for the ObjC blocks used to support libdispatch. 270typedef struct { 271 void *block; 272 dispatch_function_t func; 273 u32 parent_tid; 274} asan_block_context_t; 275 276// We use extern declarations of libdispatch functions here instead 277// of including <dispatch/dispatch.h>. This header is not present on 278// Mac OS X Leopard and eariler, and although we don't expect ASan to 279// work on legacy systems, it's bad to break the build of 280// LLVM compiler-rt there. 281extern "C" { 282void dispatch_async_f(dispatch_queue_t dq, void *ctxt, 283 dispatch_function_t func); 284void dispatch_sync_f(dispatch_queue_t dq, void *ctxt, 285 dispatch_function_t func); 286void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt, 287 dispatch_function_t func); 288void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, 289 dispatch_function_t func); 290void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq, 291 void *ctxt, dispatch_function_t func); 292int pthread_workqueue_additem_np(pthread_workqueue_t workq, 293 void *(*workitem_func)(void *), void * workitem_arg, 294 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp); 295} // extern "C" 296 297static ALWAYS_INLINE 298void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 299 AsanThread *t = asanThreadRegistry().GetCurrent(); 300 if (!t) { 301 t = AsanThread::Create(parent_tid, 0, 0, stack); 302 asanThreadRegistry().RegisterThread(t); 303 t->Init(); 304 asanThreadRegistry().SetCurrent(t); 305 } 306} 307 308// For use by only those functions that allocated the context via 309// alloc_asan_context(). 310extern "C" 311void asan_dispatch_call_block_and_release(void *block) { 312 GET_STACK_TRACE_THREAD; 313 asan_block_context_t *context = (asan_block_context_t*)block; 314 if (flags()->verbosity >= 2) { 315 Report("asan_dispatch_call_block_and_release(): " 316 "context: %p, pthread_self: %p\n", 317 block, pthread_self()); 318 } 319 asan_register_worker_thread(context->parent_tid, &stack); 320 // Call the original dispatcher for the block. 321 context->func(context->block); 322 asan_free(context, &stack, FROM_MALLOC); 323} 324 325} // namespace __asan 326 327using namespace __asan; // NOLINT 328 329// Wrap |ctxt| and |func| into an asan_block_context_t. 330// The caller retains control of the allocated context. 331extern "C" 332asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 333 StackTrace *stack) { 334 asan_block_context_t *asan_ctxt = 335 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 336 asan_ctxt->block = ctxt; 337 asan_ctxt->func = func; 338 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 339 return asan_ctxt; 340} 341 342// Define interceptor for dispatch_*_f function with the three most common 343// parameters: dispatch_queue_t, context, dispatch_function_t. 344#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 345 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 346 dispatch_function_t func) { \ 347 GET_STACK_TRACE_THREAD; \ 348 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 349 if (flags()->verbosity >= 2) { \ 350 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 351 asan_ctxt, pthread_self()); \ 352 PRINT_CURRENT_STACK(); \ 353 } \ 354 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 355 asan_dispatch_call_block_and_release); \ 356 } 357 358INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 359INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 360INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 361 362INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 363 dispatch_queue_t dq, void *ctxt, 364 dispatch_function_t func) { 365 GET_STACK_TRACE_THREAD; 366 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 367 if (flags()->verbosity >= 2) { 368 Report("dispatch_after_f: %p\n", asan_ctxt); 369 PRINT_CURRENT_STACK(); 370 } 371 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 372 asan_dispatch_call_block_and_release); 373} 374 375INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 376 dispatch_queue_t dq, void *ctxt, 377 dispatch_function_t func) { 378 GET_STACK_TRACE_THREAD; 379 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 380 if (flags()->verbosity >= 2) { 381 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 382 asan_ctxt, pthread_self()); 383 PRINT_CURRENT_STACK(); 384 } 385 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 386 asan_dispatch_call_block_and_release); 387} 388 389#if MAC_INTERPOSE_FUNCTIONS && !defined(MISSING_BLOCKS_SUPPORT) 390// dispatch_async, dispatch_group_async and others tailcall the corresponding 391// dispatch_*_f functions. When wrapping functions with mach_override, those 392// dispatch_*_f are intercepted automatically. But with dylib interposition 393// this does not work, because the calls within the same library are not 394// interposed. 395// Therefore we need to re-implement dispatch_async and friends. 396 397extern "C" { 398// FIXME: consolidate these declarations with asan_intercepted_functions.h. 399void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 400void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 401 void(^work)(void)); 402void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 403 void(^work)(void)); 404void dispatch_source_set_cancel_handler(dispatch_source_t ds, 405 void(^work)(void)); 406void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 407} 408 409#define GET_ASAN_BLOCK(work) \ 410 void (^asan_block)(void); \ 411 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 412 asan_block = ^(void) { \ 413 GET_STACK_TRACE_THREAD; \ 414 asan_register_worker_thread(parent_tid, &stack); \ 415 work(); \ 416 } 417 418INTERCEPTOR(void, dispatch_async, 419 dispatch_queue_t dq, void(^work)(void)) { 420 GET_ASAN_BLOCK(work); 421 REAL(dispatch_async)(dq, asan_block); 422} 423 424INTERCEPTOR(void, dispatch_group_async, 425 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 426 GET_ASAN_BLOCK(work); 427 REAL(dispatch_group_async)(dg, dq, asan_block); 428} 429 430INTERCEPTOR(void, dispatch_after, 431 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 432 GET_ASAN_BLOCK(work); 433 REAL(dispatch_after)(when, queue, asan_block); 434} 435 436INTERCEPTOR(void, dispatch_source_set_cancel_handler, 437 dispatch_source_t ds, void(^work)(void)) { 438 GET_ASAN_BLOCK(work); 439 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 440} 441 442INTERCEPTOR(void, dispatch_source_set_event_handler, 443 dispatch_source_t ds, void(^work)(void)) { 444 GET_ASAN_BLOCK(work); 445 REAL(dispatch_source_set_event_handler)(ds, asan_block); 446} 447#endif 448 449// The following stuff has been extremely helpful while looking for the 450// unhandled functions that spawned jobs on Chromium shutdown. If the verbosity 451// level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to 452// find the points of worker thread creation (each of such threads may be used 453// to run several tasks, that's why this is not enough to support the whole 454// libdispatch API. 455extern "C" 456void *wrap_workitem_func(void *arg) { 457 if (flags()->verbosity >= 2) { 458 Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self()); 459 } 460 asan_block_context_t *ctxt = (asan_block_context_t*)arg; 461 worker_t fn = (worker_t)(ctxt->func); 462 void *result = fn(ctxt->block); 463 GET_STACK_TRACE_THREAD; 464 asan_free(arg, &stack, FROM_MALLOC); 465 return result; 466} 467 468INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq, 469 void *(*workitem_func)(void *), void * workitem_arg, 470 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) { 471 GET_STACK_TRACE_THREAD; 472 asan_block_context_t *asan_ctxt = 473 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack); 474 asan_ctxt->block = workitem_arg; 475 asan_ctxt->func = (dispatch_function_t)workitem_func; 476 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 477 if (flags()->verbosity >= 2) { 478 Report("pthread_workqueue_additem_np: %p\n", asan_ctxt); 479 PRINT_CURRENT_STACK(); 480 } 481 return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func, 482 asan_ctxt, itemhandlep, 483 gencountp); 484} 485 486// See http://opensource.apple.com/source/CF/CF-635.15/CFString.c 487int __CFStrIsConstant(CFStringRef str) { 488 CFRuntimeBase *base = (CFRuntimeBase*)str; 489#if __LP64__ 490 return base->_rc == 0; 491#else 492 return (base->_cfinfo[CF_RC_BITS]) == 0; 493#endif 494} 495 496INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc, 497 CFStringRef str) { 498 if (__CFStrIsConstant(str)) { 499 return str; 500 } else { 501 return REAL(CFStringCreateCopy)(alloc, str); 502 } 503} 504 505DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr) 506 507DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize, void) 508 509namespace __asan { 510 511void InitializeMacInterceptors() { 512 CHECK(INTERCEPT_FUNCTION(dispatch_async_f)); 513 CHECK(INTERCEPT_FUNCTION(dispatch_sync_f)); 514 CHECK(INTERCEPT_FUNCTION(dispatch_after_f)); 515 CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f)); 516 CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f)); 517 // We don't need to intercept pthread_workqueue_additem_np() to support the 518 // libdispatch API, but it helps us to debug the unsupported functions. Let's 519 // intercept it only during verbose runs. 520 if (flags()->verbosity >= 2) { 521 CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np)); 522 } 523 // Normally CFStringCreateCopy should not copy constant CF strings. 524 // Replacing the default CFAllocator causes constant strings to be copied 525 // rather than just returned, which leads to bugs in big applications like 526 // Chromium and WebKit, see 527 // http://code.google.com/p/address-sanitizer/issues/detail?id=10 528 // Until this problem is fixed we need to check that the string is 529 // non-constant before calling CFStringCreateCopy. 530 CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy)); 531 // Some of the library functions call free() directly, so we have to 532 // intercept it. 533 CHECK(INTERCEPT_FUNCTION(free)); 534 if (flags()->replace_cfallocator) { 535 CHECK(INTERCEPT_FUNCTION(__CFInitialize)); 536 } 537} 538 539} // namespace __asan 540 541#endif // __APPLE__ 542