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 40 namespace __asan { 41 42 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) { 43 ucontext_t *ucontext = (ucontext_t*)context; 44 # if SANITIZER_WORDSIZE == 64 45 *pc = ucontext->uc_mcontext->__ss.__rip; 46 *bp = ucontext->uc_mcontext->__ss.__rbp; 47 *sp = ucontext->uc_mcontext->__ss.__rsp; 48 # else 49 *pc = ucontext->uc_mcontext->__ss.__eip; 50 *bp = ucontext->uc_mcontext->__ss.__ebp; 51 *sp = ucontext->uc_mcontext->__ss.__esp; 52 # endif // SANITIZER_WORDSIZE 53 } 54 55 int GetMacosVersion() { 56 int mib[2] = { CTL_KERN, KERN_OSRELEASE }; 57 char version[100]; 58 uptr len = 0, maxlen = sizeof(version) / sizeof(version[0]); 59 for (uptr i = 0; i < maxlen; i++) version[i] = '\0'; 60 // Get the version length. 61 CHECK(sysctl(mib, 2, 0, &len, 0, 0) != -1); 62 CHECK(len < maxlen); 63 CHECK(sysctl(mib, 2, version, &len, 0, 0) != -1); 64 switch (version[0]) { 65 case '9': return MACOS_VERSION_LEOPARD; 66 case '1': { 67 switch (version[1]) { 68 case '0': return MACOS_VERSION_SNOW_LEOPARD; 69 case '1': return MACOS_VERSION_LION; 70 case '2': return MACOS_VERSION_MOUNTAIN_LION; 71 default: return MACOS_VERSION_UNKNOWN; 72 } 73 } 74 default: return MACOS_VERSION_UNKNOWN; 75 } 76 } 77 78 bool 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 87 extern "C" 88 void __asan_init(); 89 90 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES"; 91 LowLevelAllocator allocator_for_env; 92 93 // Change the value of the env var |name|, leaking the original value. 94 // If |name_value| is NULL, the variable is deleted from the environment, 95 // otherwise the corresponding "NAME=value" string is replaced with 96 // |name_value|. 97 void LeakyResetEnv(const char *name, const char *name_value) { 98 char ***env_ptr = _NSGetEnviron(); 99 CHECK(env_ptr); 100 char **environ = *env_ptr; 101 CHECK(environ); 102 uptr name_len = internal_strlen(name); 103 while (*environ != 0) { 104 uptr len = internal_strlen(*environ); 105 if (len > name_len) { 106 const char *p = *environ; 107 if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') { 108 // Match. 109 if (name_value) { 110 // Replace the old value with the new one. 111 *environ = const_cast<char*>(name_value); 112 } else { 113 // Shift the subsequent pointers back. 114 char **del = environ; 115 do { 116 del[0] = del[1]; 117 } while (*del++); 118 } 119 } 120 } 121 environ++; 122 } 123 } 124 125 void MaybeReexec() { 126 if (!flags()->allow_reexec) return; 127 // Make sure the dynamic ASan runtime library is preloaded so that the 128 // wrappers work. If it is not, set DYLD_INSERT_LIBRARIES and re-exec 129 // ourselves. 130 Dl_info info; 131 CHECK(dladdr((void*)((uptr)__asan_init), &info)); 132 char *dyld_insert_libraries = 133 const_cast<char*>(GetEnv(kDyldInsertLibraries)); 134 uptr old_env_len = dyld_insert_libraries ? 135 internal_strlen(dyld_insert_libraries) : 0; 136 uptr fname_len = internal_strlen(info.dli_fname); 137 if (!dyld_insert_libraries || 138 !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) { 139 // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime 140 // library. 141 char program_name[1024]; 142 uint32_t buf_size = sizeof(program_name); 143 _NSGetExecutablePath(program_name, &buf_size); 144 char *new_env = const_cast<char*>(info.dli_fname); 145 if (dyld_insert_libraries) { 146 // Append the runtime dylib name to the existing value of 147 // DYLD_INSERT_LIBRARIES. 148 new_env = (char*)allocator_for_env.Allocate(old_env_len + fname_len + 2); 149 internal_strncpy(new_env, dyld_insert_libraries, old_env_len); 150 new_env[old_env_len] = ':'; 151 // Copy fname_len and add a trailing zero. 152 internal_strncpy(new_env + old_env_len + 1, info.dli_fname, 153 fname_len + 1); 154 // Ok to use setenv() since the wrappers don't depend on the value of 155 // asan_inited. 156 setenv(kDyldInsertLibraries, new_env, /*overwrite*/1); 157 } else { 158 // Set DYLD_INSERT_LIBRARIES equal to the runtime dylib name. 159 setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0); 160 } 161 if (flags()->verbosity >= 1) { 162 Report("exec()-ing the program with\n"); 163 Report("%s=%s\n", kDyldInsertLibraries, new_env); 164 Report("to enable ASan wrappers.\n"); 165 Report("Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n"); 166 } 167 execv(program_name, *_NSGetArgv()); 168 } else { 169 // DYLD_INSERT_LIBRARIES is set and contains the runtime library. 170 if (old_env_len == fname_len) { 171 // It's just the runtime library name - fine to unset the variable. 172 LeakyResetEnv(kDyldInsertLibraries, NULL); 173 } else { 174 uptr env_name_len = internal_strlen(kDyldInsertLibraries); 175 // Allocate memory to hold the previous env var name, its value, the '=' 176 // sign and the '\0' char. 177 char *new_env = (char*)allocator_for_env.Allocate( 178 old_env_len + 2 + env_name_len); 179 CHECK(new_env); 180 internal_memset(new_env, '\0', old_env_len + 2 + env_name_len); 181 internal_strncpy(new_env, kDyldInsertLibraries, env_name_len); 182 new_env[env_name_len] = '='; 183 char *new_env_pos = new_env + env_name_len + 1; 184 185 // Iterate over colon-separated pieces of |dyld_insert_libraries|. 186 char *piece_start = dyld_insert_libraries; 187 char *piece_end = NULL; 188 char *old_env_end = dyld_insert_libraries + old_env_len; 189 do { 190 if (piece_start[0] == ':') piece_start++; 191 piece_end = REAL(strchr)(piece_start, ':'); 192 if (!piece_end) piece_end = dyld_insert_libraries + old_env_len; 193 if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break; 194 uptr piece_len = piece_end - piece_start; 195 196 // If the current piece isn't the runtime library name, 197 // append it to new_env. 198 if ((piece_len != fname_len) || 199 (internal_strncmp(piece_start, info.dli_fname, fname_len) != 0)) { 200 if (new_env_pos != new_env + env_name_len + 1) { 201 new_env_pos[0] = ':'; 202 new_env_pos++; 203 } 204 internal_strncpy(new_env_pos, piece_start, piece_len); 205 } 206 // Move on to the next piece. 207 new_env_pos += piece_len; 208 piece_start = piece_end; 209 } while (piece_start < old_env_end); 210 211 // Can't use setenv() here, because it requires the allocator to be 212 // initialized. 213 // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in 214 // a separate function called after InitializeAllocator(). 215 LeakyResetEnv(kDyldInsertLibraries, new_env); 216 } 217 } 218 } 219 220 // No-op. Mac does not support static linkage anyway. 221 void *AsanDoesNotSupportStaticLinkage() { 222 return 0; 223 } 224 225 bool AsanInterceptsSignal(int signum) { 226 return (signum == SIGSEGV || signum == SIGBUS) && flags()->handle_segv; 227 } 228 229 void AsanPlatformThreadInit() { 230 } 231 232 void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, bool fast) { 233 (void)fast; 234 stack->size = 0; 235 stack->trace[0] = pc; 236 if ((max_s) > 1) { 237 stack->max_size = max_s; 238 if (!asan_inited) return; 239 if (AsanThread *t = asanThreadRegistry().GetCurrent()) 240 stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom()); 241 } 242 } 243 244 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 245 UNIMPLEMENTED(); 246 } 247 248 // Support for the following functions from libdispatch on Mac OS: 249 // dispatch_async_f() 250 // dispatch_async() 251 // dispatch_sync_f() 252 // dispatch_sync() 253 // dispatch_after_f() 254 // dispatch_after() 255 // dispatch_group_async_f() 256 // dispatch_group_async() 257 // TODO(glider): libdispatch API contains other functions that we don't support 258 // yet. 259 // 260 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 261 // they can cause jobs to run on a thread different from the current one. 262 // TODO(glider): if so, we need a test for this (otherwise we should remove 263 // them). 264 // 265 // The following functions use dispatch_barrier_async_f() (which isn't a library 266 // function but is exported) and are thus supported: 267 // dispatch_source_set_cancel_handler_f() 268 // dispatch_source_set_cancel_handler() 269 // dispatch_source_set_event_handler_f() 270 // dispatch_source_set_event_handler() 271 // 272 // The reference manual for Grand Central Dispatch is available at 273 // http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 274 // The implementation details are at 275 // http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 276 277 typedef void* dispatch_group_t; 278 typedef void* dispatch_queue_t; 279 typedef void* dispatch_source_t; 280 typedef u64 dispatch_time_t; 281 typedef void (*dispatch_function_t)(void *block); 282 typedef void* (*worker_t)(void *block); 283 284 // A wrapper for the ObjC blocks used to support libdispatch. 285 typedef struct { 286 void *block; 287 dispatch_function_t func; 288 u32 parent_tid; 289 } asan_block_context_t; 290 291 static ALWAYS_INLINE 292 void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 293 AsanThread *t = asanThreadRegistry().GetCurrent(); 294 if (!t) { 295 t = AsanThread::Create(parent_tid, 0, 0, stack); 296 asanThreadRegistry().RegisterThread(t); 297 t->Init(); 298 asanThreadRegistry().SetCurrent(t); 299 } 300 } 301 302 // For use by only those functions that allocated the context via 303 // alloc_asan_context(). 304 extern "C" 305 void asan_dispatch_call_block_and_release(void *block) { 306 GET_STACK_TRACE_THREAD; 307 asan_block_context_t *context = (asan_block_context_t*)block; 308 if (flags()->verbosity >= 2) { 309 Report("asan_dispatch_call_block_and_release(): " 310 "context: %p, pthread_self: %p\n", 311 block, pthread_self()); 312 } 313 asan_register_worker_thread(context->parent_tid, &stack); 314 // Call the original dispatcher for the block. 315 context->func(context->block); 316 asan_free(context, &stack, FROM_MALLOC); 317 } 318 319 } // namespace __asan 320 321 using namespace __asan; // NOLINT 322 323 // Wrap |ctxt| and |func| into an asan_block_context_t. 324 // The caller retains control of the allocated context. 325 extern "C" 326 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 327 StackTrace *stack) { 328 asan_block_context_t *asan_ctxt = 329 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 330 asan_ctxt->block = ctxt; 331 asan_ctxt->func = func; 332 asan_ctxt->parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); 333 return asan_ctxt; 334 } 335 336 // Define interceptor for dispatch_*_f function with the three most common 337 // parameters: dispatch_queue_t, context, dispatch_function_t. 338 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 339 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 340 dispatch_function_t func) { \ 341 GET_STACK_TRACE_THREAD; \ 342 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 343 if (flags()->verbosity >= 2) { \ 344 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 345 asan_ctxt, pthread_self()); \ 346 PRINT_CURRENT_STACK(); \ 347 } \ 348 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 349 asan_dispatch_call_block_and_release); \ 350 } 351 352 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 353 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 354 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 355 356 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 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_after_f: %p\n", asan_ctxt); 363 PRINT_CURRENT_STACK(); 364 } 365 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 366 asan_dispatch_call_block_and_release); 367 } 368 369 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 370 dispatch_queue_t dq, void *ctxt, 371 dispatch_function_t func) { 372 GET_STACK_TRACE_THREAD; 373 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 374 if (flags()->verbosity >= 2) { 375 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 376 asan_ctxt, pthread_self()); 377 PRINT_CURRENT_STACK(); 378 } 379 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 380 asan_dispatch_call_block_and_release); 381 } 382 383 #if !defined(MISSING_BLOCKS_SUPPORT) 384 extern "C" { 385 // FIXME: consolidate these declarations with asan_intercepted_functions.h. 386 void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 387 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 388 void(^work)(void)); 389 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 390 void(^work)(void)); 391 void dispatch_source_set_cancel_handler(dispatch_source_t ds, 392 void(^work)(void)); 393 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 394 } 395 396 #define GET_ASAN_BLOCK(work) \ 397 void (^asan_block)(void); \ 398 int parent_tid = asanThreadRegistry().GetCurrentTidOrInvalid(); \ 399 asan_block = ^(void) { \ 400 GET_STACK_TRACE_THREAD; \ 401 asan_register_worker_thread(parent_tid, &stack); \ 402 work(); \ 403 } 404 405 INTERCEPTOR(void, dispatch_async, 406 dispatch_queue_t dq, void(^work)(void)) { 407 GET_ASAN_BLOCK(work); 408 REAL(dispatch_async)(dq, asan_block); 409 } 410 411 INTERCEPTOR(void, dispatch_group_async, 412 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 413 GET_ASAN_BLOCK(work); 414 REAL(dispatch_group_async)(dg, dq, asan_block); 415 } 416 417 INTERCEPTOR(void, dispatch_after, 418 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 419 GET_ASAN_BLOCK(work); 420 REAL(dispatch_after)(when, queue, asan_block); 421 } 422 423 INTERCEPTOR(void, dispatch_source_set_cancel_handler, 424 dispatch_source_t ds, void(^work)(void)) { 425 GET_ASAN_BLOCK(work); 426 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 427 } 428 429 INTERCEPTOR(void, dispatch_source_set_event_handler, 430 dispatch_source_t ds, void(^work)(void)) { 431 GET_ASAN_BLOCK(work); 432 REAL(dispatch_source_set_event_handler)(ds, asan_block); 433 } 434 #endif 435 436 #endif // __APPLE__ 437
