asan_mac.cc revision ec3a5a21fd261f5227b5ad0d76bc148c6d227297
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 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) { 164 stack->size = 0; 165 stack->trace[0] = pc; 166 if ((max_s) > 1) { 167 stack->max_size = max_s; 168 if (!asan_inited) return; 169 if (AsanThread *t = asanThreadRegistry().GetCurrent()) 170 stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom()); 171 } 172} 173 174// The range of pages to be used for escape islands. 175// TODO(glider): instead of mapping a fixed range we must find a range of 176// unmapped pages in vmmap and take them. 177// These constants were chosen empirically and may not work if the shadow 178// memory layout changes. Unfortunately they do necessarily depend on 179// kHighMemBeg or kHighMemEnd. 180static void *island_allocator_pos = 0; 181 182#if __WORDSIZE == 32 183# define kIslandEnd (0xffdf0000 - kPageSize) 184# define kIslandBeg (kIslandEnd - 256 * kPageSize) 185#else 186# define kIslandEnd (0x7fffffdf0000 - kPageSize) 187# define kIslandBeg (kIslandEnd - 256 * kPageSize) 188#endif 189 190extern "C" 191mach_error_t __interception_allocate_island(void **ptr, 192 uptr unused_size, 193 void *unused_hint) { 194 if (!island_allocator_pos) { 195 island_allocator_pos = 196 internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg, 197 PROT_READ | PROT_WRITE | PROT_EXEC, 198 MAP_PRIVATE | MAP_ANON | MAP_FIXED, 199 -1, 0); 200 if (island_allocator_pos != (void*)kIslandBeg) { 201 return KERN_NO_SPACE; 202 } 203 if (flags()->verbosity) { 204 Report("Mapped pages %p--%p for branch islands.\n", 205 (void*)kIslandBeg, (void*)kIslandEnd); 206 } 207 // Should not be very performance-critical. 208 internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg); 209 }; 210 *ptr = island_allocator_pos; 211 island_allocator_pos = (char*)island_allocator_pos + kPageSize; 212 if (flags()->verbosity) { 213 Report("Branch island allocated at %p\n", *ptr); 214 } 215 return err_none; 216} 217 218extern "C" 219mach_error_t __interception_deallocate_island(void *ptr) { 220 // Do nothing. 221 // TODO(glider): allow to free and reuse the island memory. 222 return err_none; 223} 224 225// Support for the following functions from libdispatch on Mac OS: 226// dispatch_async_f() 227// dispatch_async() 228// dispatch_sync_f() 229// dispatch_sync() 230// dispatch_after_f() 231// dispatch_after() 232// dispatch_group_async_f() 233// dispatch_group_async() 234// TODO(glider): libdispatch API contains other functions that we don't support 235// yet. 236// 237// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 238// they can cause jobs to run on a thread different from the current one. 239// TODO(glider): if so, we need a test for this (otherwise we should remove 240// them). 241// 242// The following functions use dispatch_barrier_async_f() (which isn't a library 243// function but is exported) and are thus supported: 244// dispatch_source_set_cancel_handler_f() 245// dispatch_source_set_cancel_handler() 246// dispatch_source_set_event_handler_f() 247// dispatch_source_set_event_handler() 248// 249// The reference manual for Grand Central Dispatch is available at 250// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 251// The implementation details are at 252// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 253 254typedef void* pthread_workqueue_t; 255typedef void* pthread_workitem_handle_t; 256 257typedef void* dispatch_group_t; 258typedef void* dispatch_queue_t; 259typedef void* dispatch_source_t; 260typedef u64 dispatch_time_t; 261typedef void (*dispatch_function_t)(void *block); 262typedef void* (*worker_t)(void *block); 263 264// A wrapper for the ObjC blocks used to support libdispatch. 265typedef struct { 266 void *block; 267 dispatch_function_t func; 268 u32 parent_tid; 269} asan_block_context_t; 270 271// We use extern declarations of libdispatch functions here instead 272// of including <dispatch/dispatch.h>. This header is not present on 273// Mac OS X Leopard and eariler, and although we don't expect ASan to 274// work on legacy systems, it's bad to break the build of 275// LLVM compiler-rt there. 276extern "C" { 277void dispatch_async_f(dispatch_queue_t dq, void *ctxt, 278 dispatch_function_t func); 279void dispatch_sync_f(dispatch_queue_t dq, void *ctxt, 280 dispatch_function_t func); 281void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt, 282 dispatch_function_t func); 283void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, 284 dispatch_function_t func); 285void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq, 286 void *ctxt, dispatch_function_t func); 287int pthread_workqueue_additem_np(pthread_workqueue_t workq, 288 void *(*workitem_func)(void *), void * workitem_arg, 289 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp); 290} // extern "C" 291 292static ALWAYS_INLINE 293void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 294 AsanThread *t = asanThreadRegistry().GetCurrent(); 295 if (!t) { 296 t = AsanThread::Create(parent_tid, 0, 0, stack); 297 asanThreadRegistry().RegisterThread(t); 298 t->Init(); 299 asanThreadRegistry().SetCurrent(t); 300 } 301} 302 303// For use by only those functions that allocated the context via 304// alloc_asan_context(). 305extern "C" 306void asan_dispatch_call_block_and_release(void *block) { 307 GET_STACK_TRACE_HERE(kStackTraceMax); 308 asan_block_context_t *context = (asan_block_context_t*)block; 309 if (flags()->verbosity >= 2) { 310 Report("asan_dispatch_call_block_and_release(): " 311 "context: %p, pthread_self: %p\n", 312 block, pthread_self()); 313 } 314 asan_register_worker_thread(context->parent_tid, &stack); 315 // Call the original dispatcher for the block. 316 context->func(context->block); 317 asan_free(context, &stack); 318} 319 320} // namespace __asan 321 322using namespace __asan; // NOLINT 323 324// Wrap |ctxt| and |func| into an asan_block_context_t. 325// The caller retains control of the allocated context. 326extern "C" 327asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 328 StackTrace *stack) { 329 asan_block_context_t *asan_ctxt = 330 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 331 asan_ctxt->block = ctxt; 332 asan_ctxt->func = func; 333 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 334 return asan_ctxt; 335} 336 337// Define interceptor for dispatch_*_f function with the three most common 338// parameters: dispatch_queue_t, context, dispatch_function_t. 339#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 340 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 341 dispatch_function_t func) { \ 342 GET_STACK_TRACE_HERE(kStackTraceMax); \ 343 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 344 if (flags()->verbosity >= 2) { \ 345 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 346 asan_ctxt, pthread_self()); \ 347 PRINT_CURRENT_STACK(); \ 348 } \ 349 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 350 asan_dispatch_call_block_and_release); \ 351 } 352 353INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 354INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 355INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 356 357INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 358 dispatch_queue_t dq, void *ctxt, 359 dispatch_function_t func) { 360 GET_STACK_TRACE_HERE(kStackTraceMax); 361 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 362 if (flags()->verbosity >= 2) { 363 Report("dispatch_after_f: %p\n", asan_ctxt); 364 PRINT_CURRENT_STACK(); 365 } 366 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 367 asan_dispatch_call_block_and_release); 368} 369 370INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 371 dispatch_queue_t dq, void *ctxt, 372 dispatch_function_t func) { 373 GET_STACK_TRACE_HERE(kStackTraceMax); 374 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 375 if (flags()->verbosity >= 2) { 376 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 377 asan_ctxt, pthread_self()); 378 PRINT_CURRENT_STACK(); 379 } 380 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 381 asan_dispatch_call_block_and_release); 382} 383 384#if MAC_INTERPOSE_FUNCTIONS 385// dispatch_async, dispatch_group_async and others tailcall the corresponding 386// dispatch_*_f functions. When wrapping functions with mach_override, those 387// dispatch_*_f are intercepted automatically. But with dylib interposition 388// this does not work, because the calls within the same library are not 389// interposed. 390// Therefore we need to re-implement dispatch_async and friends. 391 392extern "C" { 393// FIXME: consolidate these declarations with asan_intercepted_functions.h. 394void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 395void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 396 void(^work)(void)); 397void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 398 void(^work)(void)); 399void dispatch_source_set_cancel_handler(dispatch_source_t ds, 400 void(^work)(void)); 401void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 402} 403 404#define GET_ASAN_BLOCK(work) \ 405 void (^asan_block)(void); \ 406 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 407 asan_block = ^(void) { \ 408 GET_STACK_TRACE_HERE(kStackTraceMax); \ 409 asan_register_worker_thread(parent_tid, &stack); \ 410 work(); \ 411 } 412 413INTERCEPTOR(void, dispatch_async, 414 dispatch_queue_t dq, void(^work)(void)) { 415 GET_ASAN_BLOCK(work); 416 REAL(dispatch_async)(dq, asan_block); 417} 418 419INTERCEPTOR(void, dispatch_group_async, 420 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 421 GET_ASAN_BLOCK(work); 422 REAL(dispatch_group_async)(dg, dq, asan_block); 423} 424 425INTERCEPTOR(void, dispatch_after, 426 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 427 GET_ASAN_BLOCK(work); 428 REAL(dispatch_after)(when, queue, asan_block); 429} 430 431INTERCEPTOR(void, dispatch_source_set_cancel_handler, 432 dispatch_source_t ds, void(^work)(void)) { 433 GET_ASAN_BLOCK(work); 434 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 435} 436 437INTERCEPTOR(void, dispatch_source_set_event_handler, 438 dispatch_source_t ds, void(^work)(void)) { 439 GET_ASAN_BLOCK(work); 440 REAL(dispatch_source_set_event_handler)(ds, asan_block); 441} 442#endif 443 444// The following stuff has been extremely helpful while looking for the 445// unhandled functions that spawned jobs on Chromium shutdown. If the verbosity 446// level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to 447// find the points of worker thread creation (each of such threads may be used 448// to run several tasks, that's why this is not enough to support the whole 449// libdispatch API. 450extern "C" 451void *wrap_workitem_func(void *arg) { 452 if (flags()->verbosity >= 2) { 453 Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self()); 454 } 455 asan_block_context_t *ctxt = (asan_block_context_t*)arg; 456 worker_t fn = (worker_t)(ctxt->func); 457 void *result = fn(ctxt->block); 458 GET_STACK_TRACE_HERE(kStackTraceMax); 459 asan_free(arg, &stack); 460 return result; 461} 462 463INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq, 464 void *(*workitem_func)(void *), void * workitem_arg, 465 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) { 466 GET_STACK_TRACE_HERE(kStackTraceMax); 467 asan_block_context_t *asan_ctxt = 468 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack); 469 asan_ctxt->block = workitem_arg; 470 asan_ctxt->func = (dispatch_function_t)workitem_func; 471 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 472 if (flags()->verbosity >= 2) { 473 Report("pthread_workqueue_additem_np: %p\n", asan_ctxt); 474 PRINT_CURRENT_STACK(); 475 } 476 return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func, 477 asan_ctxt, itemhandlep, 478 gencountp); 479} 480 481// See http://opensource.apple.com/source/CF/CF-635.15/CFString.c 482int __CFStrIsConstant(CFStringRef str) { 483 CFRuntimeBase *base = (CFRuntimeBase*)str; 484#if __LP64__ 485 return base->_rc == 0; 486#else 487 return (base->_cfinfo[CF_RC_BITS]) == 0; 488#endif 489} 490 491INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc, 492 CFStringRef str) { 493 if (__CFStrIsConstant(str)) { 494 return str; 495 } else { 496 return REAL(CFStringCreateCopy)(alloc, str); 497 } 498} 499 500DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr) 501 502DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize, void) 503 504namespace __asan { 505 506void InitializeMacInterceptors() { 507 CHECK(INTERCEPT_FUNCTION(dispatch_async_f)); 508 CHECK(INTERCEPT_FUNCTION(dispatch_sync_f)); 509 CHECK(INTERCEPT_FUNCTION(dispatch_after_f)); 510 CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f)); 511 CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f)); 512 // We don't need to intercept pthread_workqueue_additem_np() to support the 513 // libdispatch API, but it helps us to debug the unsupported functions. Let's 514 // intercept it only during verbose runs. 515 if (flags()->verbosity >= 2) { 516 CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np)); 517 } 518 // Normally CFStringCreateCopy should not copy constant CF strings. 519 // Replacing the default CFAllocator causes constant strings to be copied 520 // rather than just returned, which leads to bugs in big applications like 521 // Chromium and WebKit, see 522 // http://code.google.com/p/address-sanitizer/issues/detail?id=10 523 // Until this problem is fixed we need to check that the string is 524 // non-constant before calling CFStringCreateCopy. 525 CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy)); 526 // Some of the library functions call free() directly, so we have to 527 // intercept it. 528 CHECK(INTERCEPT_FUNCTION(free)); 529 if (flags()->replace_cfallocator) { 530 CHECK(INTERCEPT_FUNCTION(__CFInitialize)); 531 } 532} 533 534} // namespace __asan 535 536#endif // __APPLE__ 537