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 #include "sanitizer_common/sanitizer_platform.h" 16 #if SANITIZER_MAC 17 18 #include "asan_interceptors.h" 19 #include "asan_internal.h" 20 #include "asan_mac.h" 21 #include "asan_mapping.h" 22 #include "asan_stack.h" 23 #include "asan_thread.h" 24 #include "sanitizer_common/sanitizer_atomic.h" 25 #include "sanitizer_common/sanitizer_libc.h" 26 27 #include <crt_externs.h> // for _NSGetArgv 28 #include <dlfcn.h> // for dladdr() 29 #include <mach-o/dyld.h> 30 #include <mach-o/loader.h> 31 #include <sys/mman.h> 32 #include <sys/resource.h> 33 #include <sys/sysctl.h> 34 #include <sys/ucontext.h> 35 #include <fcntl.h> 36 #include <pthread.h> 37 #include <stdlib.h> // for free() 38 #include <unistd.h> 39 #include <libkern/OSAtomic.h> 40 41 namespace __asan { 42 43 void 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 56 MacosVersion cached_macos_version = MACOS_VERSION_UNINITIALIZED; 57 58 MacosVersion GetMacosVersionInternal() { 59 int mib[2] = { CTL_KERN, KERN_OSRELEASE }; 60 char version[100]; 61 uptr len = 0, maxlen = sizeof(version) / sizeof(version[0]); 62 for (uptr i = 0; i < maxlen; i++) version[i] = '\0'; 63 // Get the version length. 64 CHECK_NE(sysctl(mib, 2, 0, &len, 0, 0), -1); 65 CHECK_LT(len, maxlen); 66 CHECK_NE(sysctl(mib, 2, version, &len, 0, 0), -1); 67 switch (version[0]) { 68 case '9': return MACOS_VERSION_LEOPARD; 69 case '1': { 70 switch (version[1]) { 71 case '0': return MACOS_VERSION_SNOW_LEOPARD; 72 case '1': return MACOS_VERSION_LION; 73 case '2': return MACOS_VERSION_MOUNTAIN_LION; 74 case '3': return MACOS_VERSION_MAVERICKS; 75 default: return MACOS_VERSION_UNKNOWN; 76 } 77 } 78 default: return MACOS_VERSION_UNKNOWN; 79 } 80 } 81 82 MacosVersion GetMacosVersion() { 83 atomic_uint32_t *cache = 84 reinterpret_cast<atomic_uint32_t*>(&cached_macos_version); 85 MacosVersion result = 86 static_cast<MacosVersion>(atomic_load(cache, memory_order_acquire)); 87 if (result == MACOS_VERSION_UNINITIALIZED) { 88 result = GetMacosVersionInternal(); 89 atomic_store(cache, result, memory_order_release); 90 } 91 return result; 92 } 93 94 bool PlatformHasDifferentMemcpyAndMemmove() { 95 // On OS X 10.7 memcpy() and memmove() are both resolved 96 // into memmove$VARIANT$sse42. 97 // See also http://code.google.com/p/address-sanitizer/issues/detail?id=34. 98 // TODO(glider): need to check dynamically that memcpy() and memmove() are 99 // actually the same function. 100 return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD; 101 } 102 103 extern "C" 104 void __asan_init(); 105 106 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES"; 107 LowLevelAllocator allocator_for_env; 108 109 // Change the value of the env var |name|, leaking the original value. 110 // If |name_value| is NULL, the variable is deleted from the environment, 111 // otherwise the corresponding "NAME=value" string is replaced with 112 // |name_value|. 113 void LeakyResetEnv(const char *name, const char *name_value) { 114 char ***env_ptr = _NSGetEnviron(); 115 CHECK(env_ptr); 116 char **environ = *env_ptr; 117 CHECK(environ); 118 uptr name_len = internal_strlen(name); 119 while (*environ != 0) { 120 uptr len = internal_strlen(*environ); 121 if (len > name_len) { 122 const char *p = *environ; 123 if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') { 124 // Match. 125 if (name_value) { 126 // Replace the old value with the new one. 127 *environ = const_cast<char*>(name_value); 128 } else { 129 // Shift the subsequent pointers back. 130 char **del = environ; 131 do { 132 del[0] = del[1]; 133 } while (*del++); 134 } 135 } 136 } 137 environ++; 138 } 139 } 140 141 void MaybeReexec() { 142 if (!flags()->allow_reexec) return; 143 // Make sure the dynamic ASan runtime library is preloaded so that the 144 // wrappers work. If it is not, set DYLD_INSERT_LIBRARIES and re-exec 145 // ourselves. 146 Dl_info info; 147 CHECK(dladdr((void*)((uptr)__asan_init), &info)); 148 char *dyld_insert_libraries = 149 const_cast<char*>(GetEnv(kDyldInsertLibraries)); 150 uptr old_env_len = dyld_insert_libraries ? 151 internal_strlen(dyld_insert_libraries) : 0; 152 uptr fname_len = internal_strlen(info.dli_fname); 153 if (!dyld_insert_libraries || 154 !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) { 155 // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime 156 // library. 157 char program_name[1024]; 158 uint32_t buf_size = sizeof(program_name); 159 _NSGetExecutablePath(program_name, &buf_size); 160 char *new_env = const_cast<char*>(info.dli_fname); 161 if (dyld_insert_libraries) { 162 // Append the runtime dylib name to the existing value of 163 // DYLD_INSERT_LIBRARIES. 164 new_env = (char*)allocator_for_env.Allocate(old_env_len + fname_len + 2); 165 internal_strncpy(new_env, dyld_insert_libraries, old_env_len); 166 new_env[old_env_len] = ':'; 167 // Copy fname_len and add a trailing zero. 168 internal_strncpy(new_env + old_env_len + 1, info.dli_fname, 169 fname_len + 1); 170 // Ok to use setenv() since the wrappers don't depend on the value of 171 // asan_inited. 172 setenv(kDyldInsertLibraries, new_env, /*overwrite*/1); 173 } else { 174 // Set DYLD_INSERT_LIBRARIES equal to the runtime dylib name. 175 setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0); 176 } 177 if (flags()->verbosity >= 1) { 178 Report("exec()-ing the program with\n"); 179 Report("%s=%s\n", kDyldInsertLibraries, new_env); 180 Report("to enable ASan wrappers.\n"); 181 Report("Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n"); 182 } 183 execv(program_name, *_NSGetArgv()); 184 } else { 185 // DYLD_INSERT_LIBRARIES is set and contains the runtime library. 186 if (old_env_len == fname_len) { 187 // It's just the runtime library name - fine to unset the variable. 188 LeakyResetEnv(kDyldInsertLibraries, NULL); 189 } else { 190 uptr env_name_len = internal_strlen(kDyldInsertLibraries); 191 // Allocate memory to hold the previous env var name, its value, the '=' 192 // sign and the '\0' char. 193 char *new_env = (char*)allocator_for_env.Allocate( 194 old_env_len + 2 + env_name_len); 195 CHECK(new_env); 196 internal_memset(new_env, '\0', old_env_len + 2 + env_name_len); 197 internal_strncpy(new_env, kDyldInsertLibraries, env_name_len); 198 new_env[env_name_len] = '='; 199 char *new_env_pos = new_env + env_name_len + 1; 200 201 // Iterate over colon-separated pieces of |dyld_insert_libraries|. 202 char *piece_start = dyld_insert_libraries; 203 char *piece_end = NULL; 204 char *old_env_end = dyld_insert_libraries + old_env_len; 205 do { 206 if (piece_start[0] == ':') piece_start++; 207 piece_end = REAL(strchr)(piece_start, ':'); 208 if (!piece_end) piece_end = dyld_insert_libraries + old_env_len; 209 if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break; 210 uptr piece_len = piece_end - piece_start; 211 212 // If the current piece isn't the runtime library name, 213 // append it to new_env. 214 if ((piece_len != fname_len) || 215 (internal_strncmp(piece_start, info.dli_fname, fname_len) != 0)) { 216 if (new_env_pos != new_env + env_name_len + 1) { 217 new_env_pos[0] = ':'; 218 new_env_pos++; 219 } 220 internal_strncpy(new_env_pos, piece_start, piece_len); 221 } 222 // Move on to the next piece. 223 new_env_pos += piece_len; 224 piece_start = piece_end; 225 } while (piece_start < old_env_end); 226 227 // Can't use setenv() here, because it requires the allocator to be 228 // initialized. 229 // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in 230 // a separate function called after InitializeAllocator(). 231 LeakyResetEnv(kDyldInsertLibraries, new_env); 232 } 233 } 234 } 235 236 // No-op. Mac does not support static linkage anyway. 237 void *AsanDoesNotSupportStaticLinkage() { 238 return 0; 239 } 240 241 bool AsanInterceptsSignal(int signum) { 242 return (signum == SIGSEGV || signum == SIGBUS) && flags()->handle_segv; 243 } 244 245 void AsanPlatformThreadInit() { 246 } 247 248 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 249 UNIMPLEMENTED(); 250 } 251 252 // Support for the following functions from libdispatch on Mac OS: 253 // dispatch_async_f() 254 // dispatch_async() 255 // dispatch_sync_f() 256 // dispatch_sync() 257 // dispatch_after_f() 258 // dispatch_after() 259 // dispatch_group_async_f() 260 // dispatch_group_async() 261 // TODO(glider): libdispatch API contains other functions that we don't support 262 // yet. 263 // 264 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 265 // they can cause jobs to run on a thread different from the current one. 266 // TODO(glider): if so, we need a test for this (otherwise we should remove 267 // them). 268 // 269 // The following functions use dispatch_barrier_async_f() (which isn't a library 270 // function but is exported) and are thus supported: 271 // dispatch_source_set_cancel_handler_f() 272 // dispatch_source_set_cancel_handler() 273 // dispatch_source_set_event_handler_f() 274 // dispatch_source_set_event_handler() 275 // 276 // The reference manual for Grand Central Dispatch is available at 277 // http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 278 // The implementation details are at 279 // http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 280 281 typedef void* dispatch_group_t; 282 typedef void* dispatch_queue_t; 283 typedef void* dispatch_source_t; 284 typedef u64 dispatch_time_t; 285 typedef void (*dispatch_function_t)(void *block); 286 typedef void* (*worker_t)(void *block); 287 288 // A wrapper for the ObjC blocks used to support libdispatch. 289 typedef struct { 290 void *block; 291 dispatch_function_t func; 292 u32 parent_tid; 293 } asan_block_context_t; 294 295 ALWAYS_INLINE 296 void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 297 AsanThread *t = GetCurrentThread(); 298 if (!t) { 299 t = AsanThread::Create(0, 0); 300 CreateThreadContextArgs args = { t, stack }; 301 asanThreadRegistry().CreateThread(*(uptr*)t, true, parent_tid, &args); 302 t->Init(); 303 asanThreadRegistry().StartThread(t->tid(), 0, 0); 304 SetCurrentThread(t); 305 } 306 } 307 308 // For use by only those functions that allocated the context via 309 // alloc_asan_context(). 310 extern "C" 311 void 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 326 327 using namespace __asan; // NOLINT 328 329 // Wrap |ctxt| and |func| into an asan_block_context_t. 330 // The caller retains control of the allocated context. 331 extern "C" 332 asan_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 = 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 } 357 358 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 359 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 360 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 361 362 INTERCEPTOR(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 } 374 375 INTERCEPTOR(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 !defined(MISSING_BLOCKS_SUPPORT) 390 extern "C" { 391 // FIXME: consolidate these declarations with asan_intercepted_functions.h. 392 void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 393 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 394 void(^work)(void)); 395 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 396 void(^work)(void)); 397 void dispatch_source_set_cancel_handler(dispatch_source_t ds, 398 void(^work)(void)); 399 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 400 } 401 402 #define GET_ASAN_BLOCK(work) \ 403 void (^asan_block)(void); \ 404 int parent_tid = GetCurrentTidOrInvalid(); \ 405 asan_block = ^(void) { \ 406 GET_STACK_TRACE_THREAD; \ 407 asan_register_worker_thread(parent_tid, &stack); \ 408 work(); \ 409 } 410 411 INTERCEPTOR(void, dispatch_async, 412 dispatch_queue_t dq, void(^work)(void)) { 413 GET_ASAN_BLOCK(work); 414 REAL(dispatch_async)(dq, asan_block); 415 } 416 417 INTERCEPTOR(void, dispatch_group_async, 418 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 419 GET_ASAN_BLOCK(work); 420 REAL(dispatch_group_async)(dg, dq, asan_block); 421 } 422 423 INTERCEPTOR(void, dispatch_after, 424 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 425 GET_ASAN_BLOCK(work); 426 REAL(dispatch_after)(when, queue, asan_block); 427 } 428 429 INTERCEPTOR(void, dispatch_source_set_cancel_handler, 430 dispatch_source_t ds, void(^work)(void)) { 431 GET_ASAN_BLOCK(work); 432 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 433 } 434 435 INTERCEPTOR(void, dispatch_source_set_event_handler, 436 dispatch_source_t ds, void(^work)(void)) { 437 GET_ASAN_BLOCK(work); 438 REAL(dispatch_source_set_event_handler)(ds, asan_block); 439 } 440 #endif 441 442 #endif // SANITIZER_MAC 443
