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_mapping.h" 21 #include "asan_stack.h" 22 #include "asan_thread.h" 23 #include "sanitizer_common/sanitizer_atomic.h" 24 #include "sanitizer_common/sanitizer_libc.h" 25 #include "sanitizer_common/sanitizer_mac.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 57 bool PlatformHasDifferentMemcpyAndMemmove() { 58 // On OS X 10.7 memcpy() and memmove() are both resolved 59 // into memmove$VARIANT$sse42. 60 // See also http://code.google.com/p/address-sanitizer/issues/detail?id=34. 61 // TODO(glider): need to check dynamically that memcpy() and memmove() are 62 // actually the same function. 63 return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD; 64 } 65 66 extern "C" 67 void __asan_init(); 68 69 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES"; 70 LowLevelAllocator allocator_for_env; 71 72 // Change the value of the env var |name|, leaking the original value. 73 // If |name_value| is NULL, the variable is deleted from the environment, 74 // otherwise the corresponding "NAME=value" string is replaced with 75 // |name_value|. 76 void LeakyResetEnv(const char *name, const char *name_value) { 77 char ***env_ptr = _NSGetEnviron(); 78 CHECK(env_ptr); 79 char **environ = *env_ptr; 80 CHECK(environ); 81 uptr name_len = internal_strlen(name); 82 while (*environ != 0) { 83 uptr len = internal_strlen(*environ); 84 if (len > name_len) { 85 const char *p = *environ; 86 if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') { 87 // Match. 88 if (name_value) { 89 // Replace the old value with the new one. 90 *environ = const_cast<char*>(name_value); 91 } else { 92 // Shift the subsequent pointers back. 93 char **del = environ; 94 do { 95 del[0] = del[1]; 96 } while (*del++); 97 } 98 } 99 } 100 environ++; 101 } 102 } 103 104 void MaybeReexec() { 105 if (!flags()->allow_reexec) return; 106 // Make sure the dynamic ASan runtime library is preloaded so that the 107 // wrappers work. If it is not, set DYLD_INSERT_LIBRARIES and re-exec 108 // ourselves. 109 Dl_info info; 110 CHECK(dladdr((void*)((uptr)__asan_init), &info)); 111 char *dyld_insert_libraries = 112 const_cast<char*>(GetEnv(kDyldInsertLibraries)); 113 uptr old_env_len = dyld_insert_libraries ? 114 internal_strlen(dyld_insert_libraries) : 0; 115 uptr fname_len = internal_strlen(info.dli_fname); 116 if (!dyld_insert_libraries || 117 !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) { 118 // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime 119 // library. 120 char program_name[1024]; 121 uint32_t buf_size = sizeof(program_name); 122 _NSGetExecutablePath(program_name, &buf_size); 123 char *new_env = const_cast<char*>(info.dli_fname); 124 if (dyld_insert_libraries) { 125 // Append the runtime dylib name to the existing value of 126 // DYLD_INSERT_LIBRARIES. 127 new_env = (char*)allocator_for_env.Allocate(old_env_len + fname_len + 2); 128 internal_strncpy(new_env, dyld_insert_libraries, old_env_len); 129 new_env[old_env_len] = ':'; 130 // Copy fname_len and add a trailing zero. 131 internal_strncpy(new_env + old_env_len + 1, info.dli_fname, 132 fname_len + 1); 133 // Ok to use setenv() since the wrappers don't depend on the value of 134 // asan_inited. 135 setenv(kDyldInsertLibraries, new_env, /*overwrite*/1); 136 } else { 137 // Set DYLD_INSERT_LIBRARIES equal to the runtime dylib name. 138 setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0); 139 } 140 VReport(1, "exec()-ing the program with\n"); 141 VReport(1, "%s=%s\n", kDyldInsertLibraries, new_env); 142 VReport(1, "to enable ASan wrappers.\n"); 143 VReport(1, "Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n"); 144 execv(program_name, *_NSGetArgv()); 145 } else { 146 // DYLD_INSERT_LIBRARIES is set and contains the runtime library. 147 if (old_env_len == fname_len) { 148 // It's just the runtime library name - fine to unset the variable. 149 LeakyResetEnv(kDyldInsertLibraries, NULL); 150 } else { 151 uptr env_name_len = internal_strlen(kDyldInsertLibraries); 152 // Allocate memory to hold the previous env var name, its value, the '=' 153 // sign and the '\0' char. 154 char *new_env = (char*)allocator_for_env.Allocate( 155 old_env_len + 2 + env_name_len); 156 CHECK(new_env); 157 internal_memset(new_env, '\0', old_env_len + 2 + env_name_len); 158 internal_strncpy(new_env, kDyldInsertLibraries, env_name_len); 159 new_env[env_name_len] = '='; 160 char *new_env_pos = new_env + env_name_len + 1; 161 162 // Iterate over colon-separated pieces of |dyld_insert_libraries|. 163 char *piece_start = dyld_insert_libraries; 164 char *piece_end = NULL; 165 char *old_env_end = dyld_insert_libraries + old_env_len; 166 do { 167 if (piece_start[0] == ':') piece_start++; 168 piece_end = REAL(strchr)(piece_start, ':'); 169 if (!piece_end) piece_end = dyld_insert_libraries + old_env_len; 170 if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break; 171 uptr piece_len = piece_end - piece_start; 172 173 // If the current piece isn't the runtime library name, 174 // append it to new_env. 175 if ((piece_len != fname_len) || 176 (internal_strncmp(piece_start, info.dli_fname, fname_len) != 0)) { 177 if (new_env_pos != new_env + env_name_len + 1) { 178 new_env_pos[0] = ':'; 179 new_env_pos++; 180 } 181 internal_strncpy(new_env_pos, piece_start, piece_len); 182 } 183 // Move on to the next piece. 184 new_env_pos += piece_len; 185 piece_start = piece_end; 186 } while (piece_start < old_env_end); 187 188 // Can't use setenv() here, because it requires the allocator to be 189 // initialized. 190 // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in 191 // a separate function called after InitializeAllocator(). 192 LeakyResetEnv(kDyldInsertLibraries, new_env); 193 } 194 } 195 } 196 197 // No-op. Mac does not support static linkage anyway. 198 void *AsanDoesNotSupportStaticLinkage() { 199 return 0; 200 } 201 202 // No-op. Mac does not support static linkage anyway. 203 void AsanCheckDynamicRTPrereqs() {} 204 205 // No-op. Mac does not support static linkage anyway. 206 void AsanCheckIncompatibleRT() {} 207 208 bool AsanInterceptsSignal(int signum) { 209 return (signum == SIGSEGV || signum == SIGBUS) && 210 common_flags()->handle_segv; 211 } 212 213 void AsanPlatformThreadInit() { 214 } 215 216 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 217 UNIMPLEMENTED(); 218 } 219 220 // Support for the following functions from libdispatch on Mac OS: 221 // dispatch_async_f() 222 // dispatch_async() 223 // dispatch_sync_f() 224 // dispatch_sync() 225 // dispatch_after_f() 226 // dispatch_after() 227 // dispatch_group_async_f() 228 // dispatch_group_async() 229 // TODO(glider): libdispatch API contains other functions that we don't support 230 // yet. 231 // 232 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are 233 // they can cause jobs to run on a thread different from the current one. 234 // TODO(glider): if so, we need a test for this (otherwise we should remove 235 // them). 236 // 237 // The following functions use dispatch_barrier_async_f() (which isn't a library 238 // function but is exported) and are thus supported: 239 // dispatch_source_set_cancel_handler_f() 240 // dispatch_source_set_cancel_handler() 241 // dispatch_source_set_event_handler_f() 242 // dispatch_source_set_event_handler() 243 // 244 // The reference manual for Grand Central Dispatch is available at 245 // http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html 246 // The implementation details are at 247 // http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c 248 249 typedef void* dispatch_group_t; 250 typedef void* dispatch_queue_t; 251 typedef void* dispatch_source_t; 252 typedef u64 dispatch_time_t; 253 typedef void (*dispatch_function_t)(void *block); 254 typedef void* (*worker_t)(void *block); 255 256 // A wrapper for the ObjC blocks used to support libdispatch. 257 typedef struct { 258 void *block; 259 dispatch_function_t func; 260 u32 parent_tid; 261 } asan_block_context_t; 262 263 ALWAYS_INLINE 264 void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 265 AsanThread *t = GetCurrentThread(); 266 if (!t) { 267 t = AsanThread::Create(0, 0); 268 CreateThreadContextArgs args = { t, stack }; 269 asanThreadRegistry().CreateThread(*(uptr*)t, true, parent_tid, &args); 270 t->Init(); 271 asanThreadRegistry().StartThread(t->tid(), 0, 0); 272 SetCurrentThread(t); 273 } 274 } 275 276 // For use by only those functions that allocated the context via 277 // alloc_asan_context(). 278 extern "C" 279 void asan_dispatch_call_block_and_release(void *block) { 280 GET_STACK_TRACE_THREAD; 281 asan_block_context_t *context = (asan_block_context_t*)block; 282 VReport(2, 283 "asan_dispatch_call_block_and_release(): " 284 "context: %p, pthread_self: %p\n", 285 block, pthread_self()); 286 asan_register_worker_thread(context->parent_tid, &stack); 287 // Call the original dispatcher for the block. 288 context->func(context->block); 289 asan_free(context, &stack, FROM_MALLOC); 290 } 291 292 } // namespace __asan 293 294 using namespace __asan; // NOLINT 295 296 // Wrap |ctxt| and |func| into an asan_block_context_t. 297 // The caller retains control of the allocated context. 298 extern "C" 299 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 300 StackTrace *stack) { 301 asan_block_context_t *asan_ctxt = 302 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 303 asan_ctxt->block = ctxt; 304 asan_ctxt->func = func; 305 asan_ctxt->parent_tid = GetCurrentTidOrInvalid(); 306 return asan_ctxt; 307 } 308 309 // Define interceptor for dispatch_*_f function with the three most common 310 // parameters: dispatch_queue_t, context, dispatch_function_t. 311 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 312 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 313 dispatch_function_t func) { \ 314 GET_STACK_TRACE_THREAD; \ 315 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 316 if (common_flags()->verbosity >= 2) { \ 317 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 318 asan_ctxt, pthread_self()); \ 319 PRINT_CURRENT_STACK(); \ 320 } \ 321 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 322 asan_dispatch_call_block_and_release); \ 323 } 324 325 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 326 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 327 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 328 329 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 330 dispatch_queue_t dq, void *ctxt, 331 dispatch_function_t func) { 332 GET_STACK_TRACE_THREAD; 333 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 334 if (common_flags()->verbosity >= 2) { 335 Report("dispatch_after_f: %p\n", asan_ctxt); 336 PRINT_CURRENT_STACK(); 337 } 338 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 339 asan_dispatch_call_block_and_release); 340 } 341 342 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 343 dispatch_queue_t dq, void *ctxt, 344 dispatch_function_t func) { 345 GET_STACK_TRACE_THREAD; 346 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 347 if (common_flags()->verbosity >= 2) { 348 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 349 asan_ctxt, pthread_self()); 350 PRINT_CURRENT_STACK(); 351 } 352 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 353 asan_dispatch_call_block_and_release); 354 } 355 356 #if !defined(MISSING_BLOCKS_SUPPORT) 357 extern "C" { 358 void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 359 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 360 void(^work)(void)); 361 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 362 void(^work)(void)); 363 void dispatch_source_set_cancel_handler(dispatch_source_t ds, 364 void(^work)(void)); 365 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 366 } 367 368 #define GET_ASAN_BLOCK(work) \ 369 void (^asan_block)(void); \ 370 int parent_tid = GetCurrentTidOrInvalid(); \ 371 asan_block = ^(void) { \ 372 GET_STACK_TRACE_THREAD; \ 373 asan_register_worker_thread(parent_tid, &stack); \ 374 work(); \ 375 } 376 377 // Forces the compiler to generate a frame pointer in the function. 378 #define ENABLE_FRAME_POINTER \ 379 do { \ 380 volatile uptr enable_fp; \ 381 enable_fp = GET_CURRENT_FRAME(); \ 382 } while (0) 383 384 INTERCEPTOR(void, dispatch_async, 385 dispatch_queue_t dq, void(^work)(void)) { 386 ENABLE_FRAME_POINTER; 387 GET_ASAN_BLOCK(work); 388 REAL(dispatch_async)(dq, asan_block); 389 } 390 391 INTERCEPTOR(void, dispatch_group_async, 392 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 393 ENABLE_FRAME_POINTER; 394 GET_ASAN_BLOCK(work); 395 REAL(dispatch_group_async)(dg, dq, asan_block); 396 } 397 398 INTERCEPTOR(void, dispatch_after, 399 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 400 ENABLE_FRAME_POINTER; 401 GET_ASAN_BLOCK(work); 402 REAL(dispatch_after)(when, queue, asan_block); 403 } 404 405 INTERCEPTOR(void, dispatch_source_set_cancel_handler, 406 dispatch_source_t ds, void(^work)(void)) { 407 ENABLE_FRAME_POINTER; 408 GET_ASAN_BLOCK(work); 409 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 410 } 411 412 INTERCEPTOR(void, dispatch_source_set_event_handler, 413 dispatch_source_t ds, void(^work)(void)) { 414 ENABLE_FRAME_POINTER; 415 GET_ASAN_BLOCK(work); 416 REAL(dispatch_source_set_event_handler)(ds, asan_block); 417 } 418 #endif 419 420 #endif // SANITIZER_MAC 421
