asan_mac.cc revision f4f51f2cc6fa936f0c65577f82e6b62989d546ee
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 144void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, bool fast) { 145 (void)fast; 146 stack->size = 0; 147 stack->trace[0] = pc; 148 if ((max_s) > 1) { 149 stack->max_size = max_s; 150 if (!asan_inited) return; 151 if (AsanThread *t = asanThreadRegistry().GetCurrent()) 152 stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom()); 153 } 154} 155 156void ClearShadowMemoryForContext(void *context) { 157 UNIMPLEMENTED(); 158} 159 160// The range of pages to be used for escape islands. 161// TODO(glider): instead of mapping a fixed range we must find a range of 162// unmapped pages in vmmap and take them. 163// These constants were chosen empirically and may not work if the shadow 164// memory layout changes. Unfortunately they do necessarily depend on 165// kHighMemBeg or kHighMemEnd. 166static void *island_allocator_pos = 0; 167 168#if SANITIZER_WORDSIZE == 32 169# define kIslandEnd (0xffdf0000 - GetPageSizeCached()) 170# define kIslandBeg (kIslandEnd - 256 * GetPageSizeCached()) 171#else 172# define kIslandEnd (0x7fffffdf0000 - GetPageSizeCached()) 173# define kIslandBeg (kIslandEnd - 256 * GetPageSizeCached()) 174#endif 175 176extern "C" 177mach_error_t __interception_allocate_island(void **ptr, 178 uptr unused_size, 179 void *unused_hint) { 180 if (!island_allocator_pos) { 181 island_allocator_pos = 182 internal_mmap((void*)kIslandBeg, kIslandEnd - kIslandBeg, 183 PROT_READ | PROT_WRITE | PROT_EXEC, 184 MAP_PRIVATE | MAP_ANON | MAP_FIXED, 185 -1, 0); 186 if (island_allocator_pos != (void*)kIslandBeg) { 187 return KERN_NO_SPACE; 188 } 189 if (flags()->verbosity) { 190 Report("Mapped pages %p--%p for branch islands.\n", 191 (void*)kIslandBeg, (void*)kIslandEnd); 192 } 193 // Should not be very performance-critical. 194 internal_memset(island_allocator_pos, 0xCC, kIslandEnd - kIslandBeg); 195 }; 196 *ptr = island_allocator_pos; 197 island_allocator_pos = (char*)island_allocator_pos + GetPageSizeCached(); 198 if (flags()->verbosity) { 199 Report("Branch island allocated at %p\n", *ptr); 200 } 201 return err_none; 202} 203 204extern "C" 205mach_error_t __interception_deallocate_island(void *ptr) { 206 // Do nothing. 207 // TODO(glider): allow to free and reuse the island memory. 208 return err_none; 209} 210 211// Support for the following functions from libdispatch on Mac OS: 212// dispatch_async_f() 213// dispatch_async() 214// dispatch_sync_f() 215// dispatch_sync() 216// dispatch_after_f() 217// dispatch_after() 218// dispatch_group_async_f() 219// dispatch_group_async() 220// TODO(glider): libdispatch API contains other functions that we don't support 221// yet. 222// 223// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 224// they can cause jobs to run on a thread different from the current one. 225// TODO(glider): if so, we need a test for this (otherwise we should remove 226// them). 227// 228// The following functions use dispatch_barrier_async_f() (which isn't a library 229// function but is exported) and are thus supported: 230// dispatch_source_set_cancel_handler_f() 231// dispatch_source_set_cancel_handler() 232// dispatch_source_set_event_handler_f() 233// dispatch_source_set_event_handler() 234// 235// The reference manual for Grand Central Dispatch is available at 236// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 237// The implementation details are at 238// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 239 240typedef void* pthread_workqueue_t; 241typedef void* pthread_workitem_handle_t; 242 243typedef void* dispatch_group_t; 244typedef void* dispatch_queue_t; 245typedef void* dispatch_source_t; 246typedef u64 dispatch_time_t; 247typedef void (*dispatch_function_t)(void *block); 248typedef void* (*worker_t)(void *block); 249 250// A wrapper for the ObjC blocks used to support libdispatch. 251typedef struct { 252 void *block; 253 dispatch_function_t func; 254 u32 parent_tid; 255} asan_block_context_t; 256 257// We use extern declarations of libdispatch functions here instead 258// of including <dispatch/dispatch.h>. This header is not present on 259// Mac OS X Leopard and eariler, and although we don't expect ASan to 260// work on legacy systems, it's bad to break the build of 261// LLVM compiler-rt there. 262extern "C" { 263void dispatch_async_f(dispatch_queue_t dq, void *ctxt, 264 dispatch_function_t func); 265void dispatch_sync_f(dispatch_queue_t dq, void *ctxt, 266 dispatch_function_t func); 267void dispatch_after_f(dispatch_time_t when, dispatch_queue_t dq, void *ctxt, 268 dispatch_function_t func); 269void dispatch_barrier_async_f(dispatch_queue_t dq, void *ctxt, 270 dispatch_function_t func); 271void dispatch_group_async_f(dispatch_group_t group, dispatch_queue_t dq, 272 void *ctxt, dispatch_function_t func); 273int pthread_workqueue_additem_np(pthread_workqueue_t workq, 274 void *(*workitem_func)(void *), void * workitem_arg, 275 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp); 276} // extern "C" 277 278static ALWAYS_INLINE 279void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 280 AsanThread *t = asanThreadRegistry().GetCurrent(); 281 if (!t) { 282 t = AsanThread::Create(parent_tid, 0, 0, stack); 283 asanThreadRegistry().RegisterThread(t); 284 t->Init(); 285 asanThreadRegistry().SetCurrent(t); 286 } 287} 288 289// For use by only those functions that allocated the context via 290// alloc_asan_context(). 291extern "C" 292void asan_dispatch_call_block_and_release(void *block) { 293 GET_STACK_TRACE_THREAD; 294 asan_block_context_t *context = (asan_block_context_t*)block; 295 if (flags()->verbosity >= 2) { 296 Report("asan_dispatch_call_block_and_release(): " 297 "context: %p, pthread_self: %p\n", 298 block, pthread_self()); 299 } 300 asan_register_worker_thread(context->parent_tid, &stack); 301 // Call the original dispatcher for the block. 302 context->func(context->block); 303 asan_free(context, &stack, FROM_MALLOC); 304} 305 306} // namespace __asan 307 308using namespace __asan; // NOLINT 309 310// Wrap |ctxt| and |func| into an asan_block_context_t. 311// The caller retains control of the allocated context. 312extern "C" 313asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 314 StackTrace *stack) { 315 asan_block_context_t *asan_ctxt = 316 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 317 asan_ctxt->block = ctxt; 318 asan_ctxt->func = func; 319 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 320 return asan_ctxt; 321} 322 323// Define interceptor for dispatch_*_f function with the three most common 324// parameters: dispatch_queue_t, context, dispatch_function_t. 325#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 326 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 327 dispatch_function_t func) { \ 328 GET_STACK_TRACE_THREAD; \ 329 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 330 if (flags()->verbosity >= 2) { \ 331 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 332 asan_ctxt, pthread_self()); \ 333 PRINT_CURRENT_STACK(); \ 334 } \ 335 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 336 asan_dispatch_call_block_and_release); \ 337 } 338 339INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 340INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 341INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 342 343INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 344 dispatch_queue_t dq, void *ctxt, 345 dispatch_function_t func) { 346 GET_STACK_TRACE_THREAD; 347 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 348 if (flags()->verbosity >= 2) { 349 Report("dispatch_after_f: %p\n", asan_ctxt); 350 PRINT_CURRENT_STACK(); 351 } 352 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 353 asan_dispatch_call_block_and_release); 354} 355 356INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 357 dispatch_queue_t dq, void *ctxt, 358 dispatch_function_t func) { 359 GET_STACK_TRACE_THREAD; 360 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 361 if (flags()->verbosity >= 2) { 362 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 363 asan_ctxt, pthread_self()); 364 PRINT_CURRENT_STACK(); 365 } 366 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 367 asan_dispatch_call_block_and_release); 368} 369 370#if MAC_INTERPOSE_FUNCTIONS && !defined(MISSING_BLOCKS_SUPPORT) 371// dispatch_async, dispatch_group_async and others tailcall the corresponding 372// dispatch_*_f functions. When wrapping functions with mach_override, those 373// dispatch_*_f are intercepted automatically. But with dylib interposition 374// this does not work, because the calls within the same library are not 375// interposed. 376// Therefore we need to re-implement dispatch_async and friends. 377 378extern "C" { 379// FIXME: consolidate these declarations with asan_intercepted_functions.h. 380void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 381void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 382 void(^work)(void)); 383void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 384 void(^work)(void)); 385void dispatch_source_set_cancel_handler(dispatch_source_t ds, 386 void(^work)(void)); 387void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 388} 389 390#define GET_ASAN_BLOCK(work) \ 391 void (^asan_block)(void); \ 392 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 393 asan_block = ^(void) { \ 394 GET_STACK_TRACE_THREAD; \ 395 asan_register_worker_thread(parent_tid, &stack); \ 396 work(); \ 397 } 398 399INTERCEPTOR(void, dispatch_async, 400 dispatch_queue_t dq, void(^work)(void)) { 401 GET_ASAN_BLOCK(work); 402 REAL(dispatch_async)(dq, asan_block); 403} 404 405INTERCEPTOR(void, dispatch_group_async, 406 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 407 GET_ASAN_BLOCK(work); 408 REAL(dispatch_group_async)(dg, dq, asan_block); 409} 410 411INTERCEPTOR(void, dispatch_after, 412 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 413 GET_ASAN_BLOCK(work); 414 REAL(dispatch_after)(when, queue, asan_block); 415} 416 417INTERCEPTOR(void, dispatch_source_set_cancel_handler, 418 dispatch_source_t ds, void(^work)(void)) { 419 GET_ASAN_BLOCK(work); 420 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 421} 422 423INTERCEPTOR(void, dispatch_source_set_event_handler, 424 dispatch_source_t ds, void(^work)(void)) { 425 GET_ASAN_BLOCK(work); 426 REAL(dispatch_source_set_event_handler)(ds, asan_block); 427} 428#endif 429 430// The following stuff has been extremely helpful while looking for the 431// unhandled functions that spawned jobs on Chromium shutdown. If the verbosity 432// level is 2 or greater, we wrap pthread_workqueue_additem_np() in order to 433// find the points of worker thread creation (each of such threads may be used 434// to run several tasks, that's why this is not enough to support the whole 435// libdispatch API. 436extern "C" 437void *wrap_workitem_func(void *arg) { 438 if (flags()->verbosity >= 2) { 439 Report("wrap_workitem_func: %p, pthread_self: %p\n", arg, pthread_self()); 440 } 441 asan_block_context_t *ctxt = (asan_block_context_t*)arg; 442 worker_t fn = (worker_t)(ctxt->func); 443 void *result = fn(ctxt->block); 444 GET_STACK_TRACE_THREAD; 445 asan_free(arg, &stack, FROM_MALLOC); 446 return result; 447} 448 449INTERCEPTOR(int, pthread_workqueue_additem_np, pthread_workqueue_t workq, 450 void *(*workitem_func)(void *), void * workitem_arg, 451 pthread_workitem_handle_t * itemhandlep, unsigned int *gencountp) { 452 GET_STACK_TRACE_THREAD; 453 asan_block_context_t *asan_ctxt = 454 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), &stack); 455 asan_ctxt->block = workitem_arg; 456 asan_ctxt->func = (dispatch_function_t)workitem_func; 457 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 458 if (flags()->verbosity >= 2) { 459 Report("pthread_workqueue_additem_np: %p\n", asan_ctxt); 460 PRINT_CURRENT_STACK(); 461 } 462 return REAL(pthread_workqueue_additem_np)(workq, wrap_workitem_func, 463 asan_ctxt, itemhandlep, 464 gencountp); 465} 466 467// See http://opensource.apple.com/source/CF/CF-635.15/CFString.c 468int __CFStrIsConstant(CFStringRef str) { 469 CFRuntimeBase *base = (CFRuntimeBase*)str; 470#if __LP64__ 471 return base->_rc == 0; 472#else 473 return (base->_cfinfo[CF_RC_BITS]) == 0; 474#endif 475} 476 477INTERCEPTOR(CFStringRef, CFStringCreateCopy, CFAllocatorRef alloc, 478 CFStringRef str) { 479 if (__CFStrIsConstant(str)) { 480 return str; 481 } else { 482 return REAL(CFStringCreateCopy)(alloc, str); 483 } 484} 485 486DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr) 487 488DECLARE_REAL_AND_INTERCEPTOR(void, __CFInitialize, void) 489 490namespace __asan { 491 492void InitializeMacInterceptors() { 493 CHECK(INTERCEPT_FUNCTION(dispatch_async_f)); 494 CHECK(INTERCEPT_FUNCTION(dispatch_sync_f)); 495 CHECK(INTERCEPT_FUNCTION(dispatch_after_f)); 496 CHECK(INTERCEPT_FUNCTION(dispatch_barrier_async_f)); 497 CHECK(INTERCEPT_FUNCTION(dispatch_group_async_f)); 498 // We don't need to intercept pthread_workqueue_additem_np() to support the 499 // libdispatch API, but it helps us to debug the unsupported functions. Let's 500 // intercept it only during verbose runs. 501 if (flags()->verbosity >= 2) { 502 CHECK(INTERCEPT_FUNCTION(pthread_workqueue_additem_np)); 503 } 504 // Normally CFStringCreateCopy should not copy constant CF strings. 505 // Replacing the default CFAllocator causes constant strings to be copied 506 // rather than just returned, which leads to bugs in big applications like 507 // Chromium and WebKit, see 508 // http://code.google.com/p/address-sanitizer/issues/detail?id=10 509 // Until this problem is fixed we need to check that the string is 510 // non-constant before calling CFStringCreateCopy. 511 CHECK(INTERCEPT_FUNCTION(CFStringCreateCopy)); 512 // Some of the library functions call free() directly, so we have to 513 // intercept it. 514 CHECK(INTERCEPT_FUNCTION(free)); 515 if (flags()->replace_cfallocator) { 516 CHECK(INTERCEPT_FUNCTION(__CFInitialize)); 517 } 518} 519 520} // namespace __asan 521 522#endif // __APPLE__ 523