msan.cc revision 7ad195c7686f7246d6afa36e930884efae42abee
1//===-- msan.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 MemorySanitizer. 11// 12// MemorySanitizer runtime. 13//===----------------------------------------------------------------------===// 14 15#include "msan.h" 16#include "sanitizer_common/sanitizer_atomic.h" 17#include "sanitizer_common/sanitizer_common.h" 18#include "sanitizer_common/sanitizer_flags.h" 19#include "sanitizer_common/sanitizer_libc.h" 20#include "sanitizer_common/sanitizer_procmaps.h" 21#include "sanitizer_common/sanitizer_stacktrace.h" 22#include "sanitizer_common/sanitizer_symbolizer.h" 23 24#include "interception/interception.h" 25 26// ACHTUNG! No system header includes in this file. 27 28using namespace __sanitizer; 29 30// Globals. 31static THREADLOCAL int msan_expect_umr = 0; 32static THREADLOCAL int msan_expected_umr_found = 0; 33 34static int msan_running_under_dr = 0; 35 36SANITIZER_INTERFACE_ATTRIBUTE 37THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSizeInWords]; 38 39SANITIZER_INTERFACE_ATTRIBUTE 40THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSizeInWords]; 41 42SANITIZER_INTERFACE_ATTRIBUTE 43THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSizeInWords]; 44 45SANITIZER_INTERFACE_ATTRIBUTE 46THREADLOCAL u32 __msan_retval_origin_tls; 47 48SANITIZER_INTERFACE_ATTRIBUTE 49THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSizeInWords]; 50 51SANITIZER_INTERFACE_ATTRIBUTE 52THREADLOCAL u64 __msan_va_arg_overflow_size_tls; 53 54SANITIZER_INTERFACE_ATTRIBUTE 55THREADLOCAL u32 __msan_origin_tls; 56 57static THREADLOCAL struct { 58 uptr stack_top, stack_bottom; 59} __msan_stack_bounds; 60 61static THREADLOCAL int is_in_symbolizer; 62static THREADLOCAL int is_in_loader; 63 64extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins; 65 66int __msan_get_track_origins() { 67 return &__msan_track_origins ? __msan_track_origins : 0; 68} 69 70extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going; 71 72namespace __msan { 73 74static bool IsRunningUnderDr() { 75 bool result = false; 76 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 77 const sptr kBufSize = 4095; 78 char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__); 79 while (proc_maps.Next(/* start */0, /* end */0, /* file_offset */0, 80 filename, kBufSize, /* protection */0)) { 81 if (internal_strstr(filename, "libdynamorio") != 0) { 82 result = true; 83 break; 84 } 85 } 86 UnmapOrDie(filename, kBufSize); 87 return result; 88} 89 90void EnterSymbolizer() { ++is_in_symbolizer; } 91void ExitSymbolizer() { --is_in_symbolizer; } 92bool IsInSymbolizer() { return is_in_symbolizer; } 93 94void EnterLoader() { ++is_in_loader; } 95void ExitLoader() { --is_in_loader; } 96 97extern "C" { 98SANITIZER_INTERFACE_ATTRIBUTE 99bool __msan_is_in_loader() { return is_in_loader; } 100} 101 102static Flags msan_flags; 103 104Flags *flags() { 105 return &msan_flags; 106} 107 108int msan_inited = 0; 109bool msan_init_is_running; 110 111int msan_report_count = 0; 112 113// Array of stack origins. 114// FIXME: make it resizable. 115static const uptr kNumStackOriginDescrs = 1024 * 1024; 116static const char *StackOriginDescr[kNumStackOriginDescrs]; 117static uptr StackOriginPC[kNumStackOriginDescrs]; 118static atomic_uint32_t NumStackOriginDescrs; 119 120static void ParseFlagsFromString(Flags *f, const char *str) { 121 ParseCommonFlagsFromString(str); 122 ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); 123 ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); 124 ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); 125 ParseFlag(str, &f->poison_in_malloc, "poison_in_free"); 126 ParseFlag(str, &f->exit_code, "exit_code"); 127 if (f->exit_code < 0 || f->exit_code > 127) { 128 Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); 129 Die(); 130 } 131 ParseFlag(str, &f->report_umrs, "report_umrs"); 132 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 133 134 // keep_going is an old name for halt_on_error, 135 // and it has inverse meaning. 136 f->halt_on_error = !f->halt_on_error; 137 ParseFlag(str, &f->halt_on_error, "keep_going"); 138 f->halt_on_error = !f->halt_on_error; 139 ParseFlag(str, &f->halt_on_error, "halt_on_error"); 140} 141 142static void InitializeFlags(Flags *f, const char *options) { 143 CommonFlags *cf = common_flags(); 144 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 145 cf->strip_path_prefix = ""; 146 cf->fast_unwind_on_fatal = false; 147 cf->fast_unwind_on_malloc = true; 148 cf->malloc_context_size = 20; 149 cf->handle_ioctl = true; 150 cf->log_path = 0; 151 152 internal_memset(f, 0, sizeof(*f)); 153 f->poison_heap_with_zeroes = false; 154 f->poison_stack_with_zeroes = false; 155 f->poison_in_malloc = true; 156 f->poison_in_free = true; 157 f->exit_code = 77; 158 f->report_umrs = true; 159 f->wrap_signals = true; 160 f->halt_on_error = !&__msan_keep_going; 161 162 // Override from user-specified string. 163 if (__msan_default_options) 164 ParseFlagsFromString(f, __msan_default_options()); 165 ParseFlagsFromString(f, options); 166} 167 168static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 169 if (__msan_stack_bounds.stack_top == 0) { 170 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 171 // realloc -> GetStackTrace). 172 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 173 GetThreadStackTopAndBottom(/* at_initialization */false, 174 &__msan_stack_bounds.stack_top, 175 &__msan_stack_bounds.stack_bottom); 176 } 177 *stack_top = __msan_stack_bounds.stack_top; 178 *stack_bottom = __msan_stack_bounds.stack_bottom; 179} 180 181void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 182 bool fast) { 183 if (!fast) { 184 // Block reports from our interceptors during _Unwind_Backtrace. 185 SymbolizerScope sym_scope; 186 return stack->SlowUnwindStack(pc, max_s); 187 } 188 189 uptr stack_top, stack_bottom; 190 GetCurrentStackBounds(&stack_top, &stack_bottom); 191 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom, max_s); 192} 193 194void PrintWarning(uptr pc, uptr bp) { 195 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 196} 197 198bool OriginIsValid(u32 origin) { 199 return origin != 0 && origin != (u32)-1; 200} 201 202void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 203 if (msan_expect_umr) { 204 // Printf("Expected UMR\n"); 205 __msan_origin_tls = origin; 206 msan_expected_umr_found = 1; 207 return; 208 } 209 210 ++msan_report_count; 211 212 StackTrace stack; 213 GetStackTrace(&stack, kStackTraceMax, pc, bp, 214 common_flags()->fast_unwind_on_fatal); 215 216 u32 report_origin = 217 (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; 218 ReportUMR(&stack, report_origin); 219 220 if (__msan_get_track_origins() && !OriginIsValid(origin)) { 221 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 222 "please report to MemorySanitizer developers.\n", 223 origin); 224 } 225} 226 227void UnpoisonParam(uptr n) { 228 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 229} 230 231// Backup MSan runtime TLS state. 232// Implementation must be async-signal-safe. 233// Instances of this class may live on the signal handler stack, and data size 234// may be an issue. 235void ScopedThreadLocalStateBackup::Backup() { 236 va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls; 237} 238 239void ScopedThreadLocalStateBackup::Restore() { 240 // A lame implementation that only keeps essential state and resets the rest. 241 __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls; 242 243 internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls)); 244 internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls)); 245 internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls)); 246 247 if (__msan_get_track_origins()) { 248 internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_tls)); 249 internal_memset(__msan_param_origin_tls, 0, 250 sizeof(__msan_param_origin_tls)); 251 } 252} 253 254void UnpoisonThreadLocalState() { 255} 256 257const char *GetOriginDescrIfStack(u32 id, uptr *pc) { 258 if ((id >> 31) == 0) return 0; 259 id &= (1U << 31) - 1; 260 CHECK_LT(id, kNumStackOriginDescrs); 261 if (pc) *pc = StackOriginPC[id]; 262 return StackOriginDescr[id]; 263} 264 265} // namespace __msan 266 267// Interface. 268 269using namespace __msan; 270 271void __msan_warning() { 272 GET_CALLER_PC_BP_SP; 273 (void)sp; 274 PrintWarning(pc, bp); 275 if (__msan::flags()->halt_on_error) { 276 Printf("Exiting\n"); 277 Die(); 278 } 279} 280 281void __msan_warning_noreturn() { 282 GET_CALLER_PC_BP_SP; 283 (void)sp; 284 PrintWarning(pc, bp); 285 Printf("Exiting\n"); 286 Die(); 287} 288 289void __msan_init() { 290 if (msan_inited) return; 291 msan_init_is_running = 1; 292 SanitizerToolName = "MemorySanitizer"; 293 294 SetDieCallback(MsanDie); 295 InitTlsSize(); 296 InitializeInterceptors(); 297 InstallAtExitHandler(); // Needs __cxa_atexit interceptor. 298 299 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 300 ReplaceOperatorsNewAndDelete(); 301 const char *msan_options = GetEnv("MSAN_OPTIONS"); 302 InitializeFlags(&msan_flags, msan_options); 303 __sanitizer_set_report_path(common_flags()->log_path); 304 if (StackSizeIsUnlimited()) { 305 if (common_flags()->verbosity) 306 Printf("Unlimited stack, doing reexec\n"); 307 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 308 // well, the program could have been run with unlimited stack for a reason. 309 SetStackSizeLimitInBytes(32 * 1024 * 1024); 310 ReExec(); 311 } 312 313 if (common_flags()->verbosity) 314 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 315 316 msan_running_under_dr = IsRunningUnderDr(); 317 __msan_clear_on_return(); 318 if (__msan_get_track_origins() && common_flags()->verbosity > 0) 319 Printf("msan_track_origins\n"); 320 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 321 __msan_get_track_origins())) { 322 // FIXME: prot1 = false is only required when running under DR. 323 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 324 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 325 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 326 Printf("FATAL: If running under GDB, try " 327 "'set disable-randomization off'.\n"); 328 DumpProcessMap(); 329 Die(); 330 } 331 332 const char *external_symbolizer = common_flags()->external_symbolizer_path; 333 bool symbolizer_started = 334 getSymbolizer()->InitializeExternal(external_symbolizer); 335 if (external_symbolizer && external_symbolizer[0]) { 336 CHECK(symbolizer_started); 337 } 338 339 GetThreadStackTopAndBottom(/* at_initialization */true, 340 &__msan_stack_bounds.stack_top, 341 &__msan_stack_bounds.stack_bottom); 342 if (common_flags()->verbosity) 343 Printf("MemorySanitizer init done\n"); 344 msan_init_is_running = 0; 345 msan_inited = 1; 346} 347 348void __msan_set_exit_code(int exit_code) { 349 flags()->exit_code = exit_code; 350} 351 352void __msan_set_keep_going(int keep_going) { 353 flags()->halt_on_error = !keep_going; 354} 355 356void __msan_set_expect_umr(int expect_umr) { 357 if (expect_umr) { 358 msan_expected_umr_found = 0; 359 } else if (!msan_expected_umr_found) { 360 GET_CALLER_PC_BP_SP; 361 (void)sp; 362 StackTrace stack; 363 GetStackTrace(&stack, kStackTraceMax, pc, bp, 364 common_flags()->fast_unwind_on_fatal); 365 ReportExpectedUMRNotFound(&stack); 366 Die(); 367 } 368 msan_expect_umr = expect_umr; 369} 370 371void __msan_print_shadow(const void *x, uptr size) { 372 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 373 u32 *o = (u32*)MEM_TO_ORIGIN(x); 374 for (uptr i = 0; i < size; i++) { 375 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 376 } 377 Printf("\n"); 378 if (__msan_get_track_origins()) { 379 for (uptr i = 0; i < size / 4; i++) { 380 Printf(" o: %x ", o[i]); 381 } 382 Printf("\n"); 383 } 384} 385 386void __msan_print_param_shadow() { 387 for (int i = 0; i < 16; i++) { 388 Printf("#%d:%zx ", i, __msan_param_tls[i]); 389 } 390 Printf("\n"); 391} 392 393sptr __msan_test_shadow(const void *x, uptr size) { 394 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 395 for (uptr i = 0; i < size; ++i) 396 if (s[i]) 397 return i; 398 return -1; 399} 400 401int __msan_set_poison_in_malloc(int do_poison) { 402 int old = flags()->poison_in_malloc; 403 flags()->poison_in_malloc = do_poison; 404 return old; 405} 406 407int __msan_has_dynamic_component() { 408 return msan_running_under_dr; 409} 410 411NOINLINE 412void __msan_clear_on_return() { 413 __msan_param_tls[0] = 0; 414} 415 416static void* get_tls_base() { 417 u64 p; 418 asm("mov %%fs:0, %0" 419 : "=r"(p) ::); 420 return (void*)p; 421} 422 423int __msan_get_retval_tls_offset() { 424 // volatile here is needed to avoid UB, because the compiler thinks that we 425 // are doing address arithmetics on unrelated pointers, and takes some 426 // shortcuts 427 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 428 volatile sptr tls_base_p = (sptr)get_tls_base(); 429 return retval_tls_p - tls_base_p; 430} 431 432int __msan_get_param_tls_offset() { 433 // volatile here is needed to avoid UB, because the compiler thinks that we 434 // are doing address arithmetics on unrelated pointers, and takes some 435 // shortcuts 436 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 437 volatile sptr tls_base_p = (sptr)get_tls_base(); 438 return param_tls_p - tls_base_p; 439} 440 441void __msan_partial_poison(const void* data, void* shadow, uptr size) { 442 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 443} 444 445void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 446 internal_memcpy(dst, src, size); 447 __msan_unpoison(dst, size); 448} 449 450void __msan_set_origin(const void *a, uptr size, u32 origin) { 451 // Origin mapping is 4 bytes per 4 bytes of application memory. 452 // Here we extend the range such that its left and right bounds are both 453 // 4 byte aligned. 454 if (!__msan_get_track_origins()) return; 455 uptr x = MEM_TO_ORIGIN((uptr)a); 456 uptr beg = x & ~3UL; // align down. 457 uptr end = (x + size + 3) & ~3UL; // align up. 458 u64 origin64 = ((u64)origin << 32) | origin; 459 // This is like memset, but the value is 32-bit. We unroll by 2 two write 460 // 64-bits at once. May want to unroll further to get 128-bit stores. 461 if (beg & 7ULL) { 462 *(u32*)beg = origin; 463 beg += 4; 464 } 465 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 466 *(u64*)addr = origin64; 467 if (end & 7ULL) 468 *(u32*)(end - 4) = origin; 469} 470 471// 'descr' is created at compile time and contains '----' in the beginning. 472// When we see descr for the first time we replace '----' with a uniq id 473// and set the origin to (id | (31-th bit)). 474void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 475 __msan_set_alloca_origin4(a, size, descr, 0); 476} 477 478void __msan_set_alloca_origin4(void *a, uptr size, const char *descr, uptr pc) { 479 static const u32 dash = '-'; 480 static const u32 first_timer = 481 dash + (dash << 8) + (dash << 16) + (dash << 24); 482 u32 *id_ptr = (u32*)descr; 483 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 484 u32 id = *id_ptr; 485 if (id == first_timer) { 486 id = atomic_fetch_add(&NumStackOriginDescrs, 487 1, memory_order_relaxed); 488 *id_ptr = id; 489 CHECK_LT(id, kNumStackOriginDescrs); 490 StackOriginDescr[id] = descr + 4; 491 StackOriginPC[id] = pc; 492 if (print) 493 Printf("First time: id=%d %s %p \n", id, descr + 4, pc); 494 } 495 id |= 1U << 31; 496 if (print) 497 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 498 __msan_set_origin(a, size, id); 499} 500 501const char *__msan_get_origin_descr_if_stack(u32 id) { 502 return GetOriginDescrIfStack(id, 0); 503} 504 505u32 __msan_get_origin(const void *a) { 506 if (!__msan_get_track_origins()) return 0; 507 uptr x = (uptr)a; 508 uptr aligned = x & ~3ULL; 509 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 510 return *(u32*)origin_ptr; 511} 512 513u32 __msan_get_umr_origin() { 514 return __msan_origin_tls; 515} 516 517u16 __sanitizer_unaligned_load16(const uu16 *p) { 518 __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); 519 if (__msan_get_track_origins()) 520 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 521 return *p; 522} 523u32 __sanitizer_unaligned_load32(const uu32 *p) { 524 __msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); 525 if (__msan_get_track_origins()) 526 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 527 return *p; 528} 529u64 __sanitizer_unaligned_load64(const uu64 *p) { 530 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); 531 if (__msan_get_track_origins()) 532 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 533 return *p; 534} 535void __sanitizer_unaligned_store16(uu16 *p, u16 x) { 536 *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 537 if (__msan_get_track_origins()) 538 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 539 *p = x; 540} 541void __sanitizer_unaligned_store32(uu32 *p, u32 x) { 542 *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 543 if (__msan_get_track_origins()) 544 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 545 *p = x; 546} 547void __sanitizer_unaligned_store64(uu64 *p, u64 x) { 548 *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 549 if (__msan_get_track_origins()) 550 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 551 *p = x; 552} 553 554#if !SANITIZER_SUPPORTS_WEAK_HOOKS 555extern "C" { 556SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE 557const char* __msan_default_options() { return ""; } 558} // extern "C" 559#endif 560 561