asan_mac.cc revision c3390df6670cb166119b961eb27a033fb9073496
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 __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 // __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 default: return MACOS_VERSION_UNKNOWN; 72 } 73 } 74 default: return MACOS_VERSION_UNKNOWN; 75 } 76} 77 78bool PlatformHasDifferentMemcpyAndMemmove() { 79 // On OS X 10.7 memcpy() and memmove() are both resolved 80 // into memmove$VARIANT$sse42. 81 // See also http://code.google.com/p/address-sanitizer/issues/detail?id=34. 82 // TODO(glider): need to check dynamically that memcpy() and memmove() are 83 // actually the same function. 84 return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD; 85} 86 87extern "C" 88void __asan_init(); 89 90static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES"; 91 92void MaybeReexec() { 93 if (!flags()->allow_reexec) return; 94#if MAC_INTERPOSE_FUNCTIONS 95 // If the program is linked with the dynamic ASan runtime library, make sure 96 // the library is preloaded so that the wrappers work. If it is not, set 97 // DYLD_INSERT_LIBRARIES and re-exec ourselves. 98 Dl_info info; 99 int result = dladdr((void*)__asan_init, &info); 100 const char *dyld_insert_libraries = GetEnv(kDyldInsertLibraries); 101 if (!dyld_insert_libraries || 102 !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) { 103 // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime 104 // library. 105 char program_name[1024]; 106 uint32_t buf_size = sizeof(program_name); 107 _NSGetExecutablePath(program_name, &buf_size); 108 // Ok to use setenv() since the wrappers don't depend on the value of 109 // asan_inited. 110 setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0); 111 if (flags()->verbosity >= 1) { 112 Report("exec()-ing the program with\n"); 113 Report("%s=%s\n", kDyldInsertLibraries, info.dli_fname); 114 Report("to enable ASan wrappers.\n"); 115 Report("Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n"); 116 } 117 execv(program_name, *_NSGetArgv()); 118 } 119#endif // MAC_INTERPOSE_FUNCTIONS 120 // If we're not using the dynamic runtime, do nothing. 121} 122 123// No-op. Mac does not support static linkage anyway. 124void *AsanDoesNotSupportStaticLinkage() { 125 return 0; 126} 127 128bool AsanInterceptsSignal(int signum) { 129 return (signum == SIGSEGV || signum == SIGBUS) && flags()->handle_segv; 130} 131 132void AsanPlatformThreadInit() { 133 ReplaceCFAllocator(); 134} 135 136AsanLock::AsanLock(LinkerInitialized) { 137 // We assume that OS_SPINLOCK_INIT is zero 138} 139 140void AsanLock::Lock() { 141 CHECK(sizeof(OSSpinLock) <= sizeof(opaque_storage_)); 142 CHECK(OS_SPINLOCK_INIT == 0); 143 CHECK(owner_ != (uptr)pthread_self()); 144 OSSpinLockLock((OSSpinLock*)&opaque_storage_); 145 CHECK(!owner_); 146 owner_ = (uptr)pthread_self(); 147} 148 149void AsanLock::Unlock() { 150 CHECK(owner_ == (uptr)pthread_self()); 151 owner_ = 0; 152 OSSpinLockUnlock((OSSpinLock*)&opaque_storage_); 153} 154 155void StackTrace::GetStackTrace(uptr max_s, uptr pc, uptr bp) { 156 size = 0; 157 trace[0] = pc; 158 if ((max_s) > 1) { 159 max_size = max_s; 160 FastUnwindStack(pc, bp); 161 } 162} 163 164// The range of pages to be used for escape islands. 165// TODO(glider): instead of mapping a fixed range we must find a range of 166// unmapped pages in vmmap and take them. 167// These constants were chosen empirically and may not work if the shadow 168// memory layout changes. Unfortunately they do necessarily depend on 169// kHighMemBeg or kHighMemEnd. 170static void *island_allocator_pos = 0; 171 172#if __WORDSIZE == 32 173# define kIslandEnd (0xffdf0000 - kPageSize) 174# define kIslandBeg (kIslandEnd - 256 * kPageSize) 175#else 176# define kIslandEnd (0x7fffffdf0000 - kPageSize) 177# define kIslandBeg (kIslandEnd - 256 * kPageSize) 178#endif 179 180extern "C" 181mach_error_t __interception_allocate_island(void **ptr, 182 uptr unused_size, 183 void *unused_hint) { 184 if (!island_allocator_pos) { 185 island_allocator_pos = 186 internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg, 187 PROT_READ | PROT_WRITE | PROT_EXEC, 188 MAP_PRIVATE | MAP_ANON | MAP_FIXED, 189 -1, 0); 190 if (island_allocator_pos != (void*)kIslandBeg) { 191 return KERN_NO_SPACE; 192 } 193 if (flags()->verbosity) { 194 Report("Mapped pages %p--%p for branch islands.\n", 195 (void*)kIslandBeg, (void*)kIslandEnd); 196 } 197 // Should not be very performance-critical. 198 internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg); 199 }; 200 *ptr = island_allocator_pos; 201 island_allocator_pos = (char*)island_allocator_pos + kPageSize; 202 if (flags()->verbosity) { 203 Report("Branch island allocated at %p\n", *ptr); 204 } 205 return err_none; 206} 207 208extern "C" 209mach_error_t __interception_deallocate_island(void *ptr) { 210 // Do nothing. 211 // TODO(glider): allow to free and reuse the island memory. 212 return err_none; 213} 214 215// Support for the following functions from libdispatch on Mac OS: 216// dispatch_async_f() 217// dispatch_async() 218// dispatch_sync_f() 219// dispatch_sync() 220// dispatch_after_f() 221// dispatch_after() 222// dispatch_group_async_f() 223// dispatch_group_async() 224// TODO(glider): libdispatch API contains other functions that we don't support 225// yet. 226// 227// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 228// they can cause jobs to run on a thread different from the current one. 229// TODO(glider): if so, we need a test for this (otherwise we should remove 230// them). 231// 232// The following functions use dispatch_barrier_async_f() (which isn't a library 233// function but is exported) and are thus supported: 234// dispatch_source_set_cancel_handler_f() 235// dispatch_source_set_cancel_handler() 236// dispatch_source_set_event_handler_f() 237// dispatch_source_set_event_handler() 238// 239// The reference manual for Grand Central Dispatch is available at 240// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 241// The implementation details are at 242// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 243 244typedef void* pthread_workqueue_t; 245typedef void* pthread_workitem_handle_t; 246 247typedef void* dispatch_group_t; 248typedef void* dispatch_queue_t; 249typedef void* dispatch_source_t; 250typedef u64 dispatch_time_t; 251typedef void (*dispatch_function_t)(void *block); 252typedef void* (*worker_t)(void *block); 253 254// A wrapper for the ObjC blocks used to support libdispatch. 255typedef struct { 256 void *block; 257 dispatch_function_t func; 258 u32 parent_tid; 259} asan_block_context_t; 260 261// We use extern declarations of libdispatch functions here instead 262// of including <dispatch/dispatch.h>. This header is not present on 263// Mac OS X Leopard and eariler, and although we don't expect ASan to 264// work on legacy systems, it's bad to break the build of 265// LLVM compiler-rt there. 266extern "C" { 267void dispatch_async_f(dispatch_queue_t dq, void *ctxt, 268 dispatch_function_t func); 269void dispatch_sync_f(dispatch_queue_t dq, void *ctxt, 270 dispatch_function_t func); 271void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt, 272 dispatch_function_t func); 273void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, 274 dispatch_function_t func); 275void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq, 276 void *ctxt, dispatch_function_t func); 277int pthread_workqueue_additem_np(pthread_workqueue_t workq, 278 void *(*workitem_func)(void *), void * workitem_arg, 279 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp); 280} // extern "C" 281 282static ALWAYS_INLINE 283void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 284 AsanThread *t = asanThreadRegistry().GetCurrent(); 285 if (!t) { 286 t = AsanThread::Create(parent_tid, 0, 0, stack); 287 asanThreadRegistry().RegisterThread(t); 288 t->Init(); 289 asanThreadRegistry().SetCurrent(t); 290 } 291} 292 293// For use by only those functions that allocated the context via 294// alloc_asan_context(). 295extern "C" 296void asan_dispatch_call_block_and_release(void *block) { 297 GET_STACK_TRACE_HERE(kStackTraceMax); 298 asan_block_context_t *context = (asan_block_context_t*)block; 299 if (flags()->verbosity >= 2) { 300 Report("asan_dispatch_call_block_and_release(): " 301 "context: %p, pthread_self: %p\n", 302 block, pthread_self()); 303 } 304 asan_register_worker_thread(context->parent_tid, &stack); 305 // Call the original dispatcher for the block. 306 context->func(context->block); 307 asan_free(context, &stack); 308} 309 310} // namespace __asan 311 312using namespace __asan; // NOLINT 313 314// Wrap |ctxt| and |func| into an asan_block_context_t. 315// The caller retains control of the allocated context. 316extern "C" 317asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 318 StackTrace *stack) { 319 asan_block_context_t *asan_ctxt = 320 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 321 asan_ctxt->block = ctxt; 322 asan_ctxt->func = func; 323 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 324 return asan_ctxt; 325} 326 327// Define interceptor for dispatch_*_f function with the three most common 328// parameters: dispatch_queue_t, context, dispatch_function_t. 329#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 330 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 331 dispatch_function_t func) { \ 332 GET_STACK_TRACE_HERE(kStackTraceMax); \ 333 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 334 if (flags()->verbosity >= 2) { \ 335 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 336 asan_ctxt, pthread_self()); \ 337 PRINT_CURRENT_STACK(); \ 338 } \ 339 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 340 asan_dispatch_call_block_and_release); \ 341 } 342 343INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 344INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 345INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 346 347INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 348 dispatch_queue_t dq, void *ctxt, 349 dispatch_function_t func) { 350 GET_STACK_TRACE_HERE(kStackTraceMax); 351 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 352 if (flags()->verbosity >= 2) { 353 Report("dispatch_after_f: %p\n", asan_ctxt); 354 PRINT_CURRENT_STACK(); 355 } 356 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 357 asan_dispatch_call_block_and_release); 358} 359 360INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 361 dispatch_queue_t dq, void *ctxt, 362 dispatch_function_t func) { 363 GET_STACK_TRACE_HERE(kStackTraceMax); 364 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 365 if (flags()->verbosity >= 2) { 366 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 367 asan_ctxt, pthread_self()); 368 PRINT_CURRENT_STACK(); 369 } 370 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 371 asan_dispatch_call_block_and_release); 372} 373 374#if MAC_INTERPOSE_FUNCTIONS 375// dispatch_async, dispatch_group_async and others tailcall the corresponding 376// dispatch_*_f functions. When wrapping functions with mach_override, those 377// dispatch_*_f are intercepted automatically. But with dylib interposition 378// this does not work, because the calls within the same library are not 379// interposed. 380// Therefore we need to re-implement dispatch_async and friends. 381 382extern "C" { 383// FIXME: consolidate these declarations with asan_intercepted_functions.h. 384void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 385void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 386 void(^work)(void)); 387void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 388 void(^work)(void)); 389void dispatch_source_set_cancel_handler(dispatch_source_t ds, 390 void(^work)(void)); 391void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 392} 393 394#define GET_ASAN_BLOCK(work) \ 395 void (^asan_block)(void); \ 396 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 397 asan_block = ^(void) { \ 398 GET_STACK_TRACE_HERE(kStackTraceMax); \ 399 asan_register_worker_thread(parent_tid, &stack); \ 400 work(); \ 401 } 402 403INTERCEPTOR(void, dispatch_async, 404 dispatch_queue_t dq, void(^work)(void)) { 405 GET_ASAN_BLOCK(work); 406 REAL(dispatch_async)(dq, asan_block); 407} 408 409INTERCEPTOR(void, dispatch_group_async, 410 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 411 GET_ASAN_BLOCK(work); 412 REAL(dispatch_group_async)(dg, dq, asan_block); 413} 414 415INTERCEPTOR(void, dispatch_after, 416 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 417 GET_ASAN_BLOCK(work); 418 REAL(dispatch_after)(when, queue, asan_block); 419} 420 421INTERCEPTOR(void, dispatch_source_set_cancel_handler, 422 dispatch_source_t ds, void(^work)(void)) { 423 GET_ASAN_BLOCK(work); 424 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 425} 426 427INTERCEPTOR(void, dispatch_source_set_event_handler, 428 dispatch_source_t ds, void(^work)(void)) { 429 GET_ASAN_BLOCK(work); 430 REAL(dispatch_source_set_event_handler)(ds, asan_block); 431} 432#endif 433 434// The following stuff has been extremely helpful while looking for the 435// unhandled functions that spawned jobs on Chromium shutdown. If the verbosity 436// level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to 437// find the points of worker thread creation (each of such threads may be used 438// to run several tasks, that's why this is not enough to support the whole 439// libdispatch API. 440extern "C" 441void *wrap_workitem_func(void *arg) { 442 if (flags()->verbosity >= 2) { 443 Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self()); 444 } 445 asan_block_context_t *ctxt = (asan_block_context_t*)arg; 446 worker_t fn = (worker_t)(ctxt->func); 447 void *result = fn(ctxt->block); 448 GET_STACK_TRACE_HERE(kStackTraceMax); 449 asan_free(arg, &stack); 450 return result; 451} 452 453INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq, 454 void *(*workitem_func)(void *), void * workitem_arg, 455 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) { 456 GET_STACK_TRACE_HERE(kStackTraceMax); 457 asan_block_context_t *asan_ctxt = 458 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack); 459 asan_ctxt->block = workitem_arg; 460 asan_ctxt->func = (dispatch_function_t)workitem_func; 461 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 462 if (flags()->verbosity >= 2) { 463 Report("pthread_workqueue_additem_np: %p\n", asan_ctxt); 464 PRINT_CURRENT_STACK(); 465 } 466 return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func, 467 asan_ctxt, itemhandlep, 468 gencountp); 469} 470 471// See http://opensource.apple.com/source/CF/CF-635.15/CFString.c 472int __CFStrIsConstant(CFStringRef str) { 473 CFRuntimeBase *base = (CFRuntimeBase*)str; 474#if __LP64__ 475 return base->_rc == 0; 476#else 477 return (base->_cfinfo[CF_RC_BITS]) == 0; 478#endif 479} 480 481INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc, 482 CFStringRef str) { 483 if (__CFStrIsConstant(str)) { 484 return str; 485 } else { 486 return REAL(CFStringCreateCopy)(alloc, str); 487 } 488} 489 490DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr) 491 492DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize) 493 494namespace __asan { 495 496void InitializeMacInterceptors() { 497 CHECK(INTERCEPT_FUNCTION(dispatch_async_f)); 498 CHECK(INTERCEPT_FUNCTION(dispatch_sync_f)); 499 CHECK(INTERCEPT_FUNCTION(dispatch_after_f)); 500 CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f)); 501 CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f)); 502 // We don't need to intercept pthread_workqueue_additem_np() to support the 503 // libdispatch API, but it helps us to debug the unsupported functions. Let's 504 // intercept it only during verbose runs. 505 if (flags()->verbosity >= 2) { 506 CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np)); 507 } 508 // Normally CFStringCreateCopy should not copy constant CF strings. 509 // Replacing the default CFAllocator causes constant strings to be copied 510 // rather than just returned, which leads to bugs in big applications like 511 // Chromium and WebKit, see 512 // http://code.google.com/p/address-sanitizer/issues/detail?id=10 513 // Until this problem is fixed we need to check that the string is 514 // non-constant before calling CFStringCreateCopy. 515 CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy)); 516 // Some of the library functions call free() directly, so we have to 517 // intercept it. 518 CHECK(INTERCEPT_FUNCTION(free)); 519 if (flags()->replace_cfallocator) { 520 CHECK(INTERCEPT_FUNCTION(__CFInitialize)); 521 } 522} 523 524} // namespace __asan 525 526#endif // __APPLE__ 527