asan_mac.cc revision 679bf63dba568611bf1fe6397fd0c41d43ac041a
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 ReplaceCFAllocator(); 135} 136 137AsanLock::AsanLock(LinkerInitialized) { 138 // We assume that OS_SPINLOCK_INIT is zero 139} 140 141void AsanLock::Lock() { 142 CHECK(sizeof(OSSpinLock) <= sizeof(opaque_storage_)); 143 CHECK(OS_SPINLOCK_INIT == 0); 144 CHECK(owner_ != (uptr)pthread_self()); 145 OSSpinLockLock((OSSpinLock*)&opaque_storage_); 146 CHECK(!owner_); 147 owner_ = (uptr)pthread_self(); 148} 149 150void AsanLock::Unlock() { 151 CHECK(owner_ == (uptr)pthread_self()); 152 owner_ = 0; 153 OSSpinLockUnlock((OSSpinLock*)&opaque_storage_); 154} 155 156void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp) { 157 stack->size = 0; 158 stack->trace[0] = pc; 159 if ((max_s) > 1) { 160 stack->max_size = max_s; 161 if (!asan_inited) return; 162 if (AsanThread *t = asanThreadRegistry().GetCurrent()) 163 stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom()); 164 } 165} 166 167// The range of pages to be used for escape islands. 168// TODO(glider): instead of mapping a fixed range we must find a range of 169// unmapped pages in vmmap and take them. 170// These constants were chosen empirically and may not work if the shadow 171// memory layout changes. Unfortunately they do necessarily depend on 172// kHighMemBeg or kHighMemEnd. 173static void *island_allocator_pos = 0; 174 175#if __WORDSIZE == 32 176# define kIslandEnd (0xffdf0000 - kPageSize) 177# define kIslandBeg (kIslandEnd - 256 * kPageSize) 178#else 179# define kIslandEnd (0x7fffffdf0000 - kPageSize) 180# define kIslandBeg (kIslandEnd - 256 * kPageSize) 181#endif 182 183extern "C" 184mach_error_t __interception_allocate_island(void **ptr, 185 uptr unused_size, 186 void *unused_hint) { 187 if (!island_allocator_pos) { 188 island_allocator_pos = 189 internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg, 190 PROT_READ | PROT_WRITE | PROT_EXEC, 191 MAP_PRIVATE | MAP_ANON | MAP_FIXED, 192 -1, 0); 193 if (island_allocator_pos != (void*)kIslandBeg) { 194 return KERN_NO_SPACE; 195 } 196 if (flags()->verbosity) { 197 Report("Mapped pages %p--%p for branch islands.\n", 198 (void*)kIslandBeg, (void*)kIslandEnd); 199 } 200 // Should not be very performance-critical. 201 internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg); 202 }; 203 *ptr = island_allocator_pos; 204 island_allocator_pos = (char*)island_allocator_pos + kPageSize; 205 if (flags()->verbosity) { 206 Report("Branch island allocated at %p\n", *ptr); 207 } 208 return err_none; 209} 210 211extern "C" 212mach_error_t __interception_deallocate_island(void *ptr) { 213 // Do nothing. 214 // TODO(glider): allow to free and reuse the island memory. 215 return err_none; 216} 217 218// Support for the following functions from libdispatch on Mac OS: 219// dispatch_async_f() 220// dispatch_async() 221// dispatch_sync_f() 222// dispatch_sync() 223// dispatch_after_f() 224// dispatch_after() 225// dispatch_group_async_f() 226// dispatch_group_async() 227// TODO(glider): libdispatch API contains other functions that we don't support 228// yet. 229// 230// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 231// they can cause jobs to run on a thread different from the current one. 232// TODO(glider): if so, we need a test for this (otherwise we should remove 233// them). 234// 235// The following functions use dispatch_barrier_async_f() (which isn't a library 236// function but is exported) and are thus supported: 237// dispatch_source_set_cancel_handler_f() 238// dispatch_source_set_cancel_handler() 239// dispatch_source_set_event_handler_f() 240// dispatch_source_set_event_handler() 241// 242// The reference manual for Grand Central Dispatch is available at 243// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 244// The implementation details are at 245// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 246 247typedef void* pthread_workqueue_t; 248typedef void* pthread_workitem_handle_t; 249 250typedef void* dispatch_group_t; 251typedef void* dispatch_queue_t; 252typedef void* dispatch_source_t; 253typedef u64 dispatch_time_t; 254typedef void (*dispatch_function_t)(void *block); 255typedef void* (*worker_t)(void *block); 256 257// A wrapper for the ObjC blocks used to support libdispatch. 258typedef struct { 259 void *block; 260 dispatch_function_t func; 261 u32 parent_tid; 262} asan_block_context_t; 263 264// We use extern declarations of libdispatch functions here instead 265// of including <dispatch/dispatch.h>. This header is not present on 266// Mac OS X Leopard and eariler, and although we don't expect ASan to 267// work on legacy systems, it's bad to break the build of 268// LLVM compiler-rt there. 269extern "C" { 270void dispatch_async_f(dispatch_queue_t dq, void *ctxt, 271 dispatch_function_t func); 272void dispatch_sync_f(dispatch_queue_t dq, void *ctxt, 273 dispatch_function_t func); 274void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt, 275 dispatch_function_t func); 276void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, 277 dispatch_function_t func); 278void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq, 279 void *ctxt, dispatch_function_t func); 280int pthread_workqueue_additem_np(pthread_workqueue_t workq, 281 void *(*workitem_func)(void *), void * workitem_arg, 282 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp); 283} // extern "C" 284 285static ALWAYS_INLINE 286void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 287 AsanThread *t = asanThreadRegistry().GetCurrent(); 288 if (!t) { 289 t = AsanThread::Create(parent_tid, 0, 0, stack); 290 asanThreadRegistry().RegisterThread(t); 291 t->Init(); 292 asanThreadRegistry().SetCurrent(t); 293 } 294} 295 296// For use by only those functions that allocated the context via 297// alloc_asan_context(). 298extern "C" 299void asan_dispatch_call_block_and_release(void *block) { 300 GET_STACK_TRACE_HERE(kStackTraceMax); 301 asan_block_context_t *context = (asan_block_context_t*)block; 302 if (flags()->verbosity >= 2) { 303 Report("asan_dispatch_call_block_and_release(): " 304 "context: %p, pthread_self: %p\n", 305 block, pthread_self()); 306 } 307 asan_register_worker_thread(context->parent_tid, &stack); 308 // Call the original dispatcher for the block. 309 context->func(context->block); 310 asan_free(context, &stack); 311} 312 313} // namespace __asan 314 315using namespace __asan; // NOLINT 316 317// Wrap |ctxt| and |func| into an asan_block_context_t. 318// The caller retains control of the allocated context. 319extern "C" 320asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 321 StackTrace *stack) { 322 asan_block_context_t *asan_ctxt = 323 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 324 asan_ctxt->block = ctxt; 325 asan_ctxt->func = func; 326 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 327 return asan_ctxt; 328} 329 330// Define interceptor for dispatch_*_f function with the three most common 331// parameters: dispatch_queue_t, context, dispatch_function_t. 332#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 333 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 334 dispatch_function_t func) { \ 335 GET_STACK_TRACE_HERE(kStackTraceMax); \ 336 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 337 if (flags()->verbosity >= 2) { \ 338 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 339 asan_ctxt, pthread_self()); \ 340 PRINT_CURRENT_STACK(); \ 341 } \ 342 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 343 asan_dispatch_call_block_and_release); \ 344 } 345 346INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 347INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 348INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 349 350INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 351 dispatch_queue_t dq, void *ctxt, 352 dispatch_function_t func) { 353 GET_STACK_TRACE_HERE(kStackTraceMax); 354 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 355 if (flags()->verbosity >= 2) { 356 Report("dispatch_after_f: %p\n", asan_ctxt); 357 PRINT_CURRENT_STACK(); 358 } 359 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 360 asan_dispatch_call_block_and_release); 361} 362 363INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 364 dispatch_queue_t dq, void *ctxt, 365 dispatch_function_t func) { 366 GET_STACK_TRACE_HERE(kStackTraceMax); 367 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 368 if (flags()->verbosity >= 2) { 369 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 370 asan_ctxt, pthread_self()); 371 PRINT_CURRENT_STACK(); 372 } 373 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 374 asan_dispatch_call_block_and_release); 375} 376 377#if MAC_INTERPOSE_FUNCTIONS 378// dispatch_async, dispatch_group_async and others tailcall the corresponding 379// dispatch_*_f functions. When wrapping functions with mach_override, those 380// dispatch_*_f are intercepted automatically. But with dylib interposition 381// this does not work, because the calls within the same library are not 382// interposed. 383// Therefore we need to re-implement dispatch_async and friends. 384 385extern "C" { 386// FIXME: consolidate these declarations with asan_intercepted_functions.h. 387void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 388void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 389 void(^work)(void)); 390void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 391 void(^work)(void)); 392void dispatch_source_set_cancel_handler(dispatch_source_t ds, 393 void(^work)(void)); 394void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 395} 396 397#define GET_ASAN_BLOCK(work) \ 398 void (^asan_block)(void); \ 399 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 400 asan_block = ^(void) { \ 401 GET_STACK_TRACE_HERE(kStackTraceMax); \ 402 asan_register_worker_thread(parent_tid, &stack); \ 403 work(); \ 404 } 405 406INTERCEPTOR(void, dispatch_async, 407 dispatch_queue_t dq, void(^work)(void)) { 408 GET_ASAN_BLOCK(work); 409 REAL(dispatch_async)(dq, asan_block); 410} 411 412INTERCEPTOR(void, dispatch_group_async, 413 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 414 GET_ASAN_BLOCK(work); 415 REAL(dispatch_group_async)(dg, dq, asan_block); 416} 417 418INTERCEPTOR(void, dispatch_after, 419 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 420 GET_ASAN_BLOCK(work); 421 REAL(dispatch_after)(when, queue, asan_block); 422} 423 424INTERCEPTOR(void, dispatch_source_set_cancel_handler, 425 dispatch_source_t ds, void(^work)(void)) { 426 GET_ASAN_BLOCK(work); 427 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 428} 429 430INTERCEPTOR(void, dispatch_source_set_event_handler, 431 dispatch_source_t ds, void(^work)(void)) { 432 GET_ASAN_BLOCK(work); 433 REAL(dispatch_source_set_event_handler)(ds, asan_block); 434} 435#endif 436 437// The following stuff has been extremely helpful while looking for the 438// unhandled functions that spawned jobs on Chromium shutdown. If the verbosity 439// level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to 440// find the points of worker thread creation (each of such threads may be used 441// to run several tasks, that's why this is not enough to support the whole 442// libdispatch API. 443extern "C" 444void *wrap_workitem_func(void *arg) { 445 if (flags()->verbosity >= 2) { 446 Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self()); 447 } 448 asan_block_context_t *ctxt = (asan_block_context_t*)arg; 449 worker_t fn = (worker_t)(ctxt->func); 450 void *result = fn(ctxt->block); 451 GET_STACK_TRACE_HERE(kStackTraceMax); 452 asan_free(arg, &stack); 453 return result; 454} 455 456INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq, 457 void *(*workitem_func)(void *), void * workitem_arg, 458 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) { 459 GET_STACK_TRACE_HERE(kStackTraceMax); 460 asan_block_context_t *asan_ctxt = 461 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack); 462 asan_ctxt->block = workitem_arg; 463 asan_ctxt->func = (dispatch_function_t)workitem_func; 464 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 465 if (flags()->verbosity >= 2) { 466 Report("pthread_workqueue_additem_np: %p\n", asan_ctxt); 467 PRINT_CURRENT_STACK(); 468 } 469 return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func, 470 asan_ctxt, itemhandlep, 471 gencountp); 472} 473 474// See http://opensource.apple.com/source/CF/CF-635.15/CFString.c 475int __CFStrIsConstant(CFStringRef str) { 476 CFRuntimeBase *base = (CFRuntimeBase*)str; 477#if __LP64__ 478 return base->_rc == 0; 479#else 480 return (base->_cfinfo[CF_RC_BITS]) == 0; 481#endif 482} 483 484INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc, 485 CFStringRef str) { 486 if (__CFStrIsConstant(str)) { 487 return str; 488 } else { 489 return REAL(CFStringCreateCopy)(alloc, str); 490 } 491} 492 493DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr) 494 495DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize, void) 496 497namespace __asan { 498 499void InitializeMacInterceptors() { 500 CHECK(INTERCEPT_FUNCTION(dispatch_async_f)); 501 CHECK(INTERCEPT_FUNCTION(dispatch_sync_f)); 502 CHECK(INTERCEPT_FUNCTION(dispatch_after_f)); 503 CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f)); 504 CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f)); 505 // We don't need to intercept pthread_workqueue_additem_np() to support the 506 // libdispatch API, but it helps us to debug the unsupported functions. Let's 507 // intercept it only during verbose runs. 508 if (flags()->verbosity >= 2) { 509 CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np)); 510 } 511 // Normally CFStringCreateCopy should not copy constant CF strings. 512 // Replacing the default CFAllocator causes constant strings to be copied 513 // rather than just returned, which leads to bugs in big applications like 514 // Chromium and WebKit, see 515 // http://code.google.com/p/address-sanitizer/issues/detail?id=10 516 // Until this problem is fixed we need to check that the string is 517 // non-constant before calling CFStringCreateCopy. 518 CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy)); 519 // Some of the library functions call free() directly, so we have to 520 // intercept it. 521 CHECK(INTERCEPT_FUNCTION(free)); 522 if (flags()->replace_cfallocator) { 523 CHECK(INTERCEPT_FUNCTION(__CFInitialize)); 524 } 525} 526 527} // namespace __asan 528 529#endif // __APPLE__ 530