msan.cc revision 55c7947a742aa72530eef52d902e60e5571ac3cf
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_free, "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 SetCommonFlagDefaults(); 145 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 146 cf->malloc_context_size = 20; 147 cf->handle_ioctl = true; 148 149 internal_memset(f, 0, sizeof(*f)); 150 f->poison_heap_with_zeroes = false; 151 f->poison_stack_with_zeroes = false; 152 f->poison_in_malloc = true; 153 f->poison_in_free = true; 154 f->exit_code = 77; 155 f->report_umrs = true; 156 f->wrap_signals = true; 157 f->halt_on_error = !&__msan_keep_going; 158 159 // Override from user-specified string. 160 if (__msan_default_options) 161 ParseFlagsFromString(f, __msan_default_options()); 162 ParseFlagsFromString(f, options); 163} 164 165static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 166 if (__msan_stack_bounds.stack_top == 0) { 167 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 168 // realloc -> GetStackTrace). 169 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 170 GetThreadStackTopAndBottom(/* at_initialization */false, 171 &__msan_stack_bounds.stack_top, 172 &__msan_stack_bounds.stack_bottom); 173 } 174 *stack_top = __msan_stack_bounds.stack_top; 175 *stack_bottom = __msan_stack_bounds.stack_bottom; 176} 177 178void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 179 bool request_fast_unwind) { 180 if (!StackTrace::WillUseFastUnwind(request_fast_unwind)) { 181 // Block reports from our interceptors during _Unwind_Backtrace. 182 SymbolizerScope sym_scope; 183 return stack->Unwind(max_s, pc, bp, 0, 0, request_fast_unwind); 184 } 185 uptr stack_top, stack_bottom; 186 GetCurrentStackBounds(&stack_top, &stack_bottom); 187 stack->Unwind(max_s, pc, bp, stack_top, stack_bottom, request_fast_unwind); 188} 189 190void PrintWarning(uptr pc, uptr bp) { 191 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 192} 193 194bool OriginIsValid(u32 origin) { 195 return origin != 0 && origin != (u32)-1; 196} 197 198void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 199 if (msan_expect_umr) { 200 // Printf("Expected UMR\n"); 201 __msan_origin_tls = origin; 202 msan_expected_umr_found = 1; 203 return; 204 } 205 206 ++msan_report_count; 207 208 StackTrace stack; 209 GetStackTrace(&stack, kStackTraceMax, pc, bp, 210 common_flags()->fast_unwind_on_fatal); 211 212 u32 report_origin = 213 (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; 214 ReportUMR(&stack, report_origin); 215 216 if (__msan_get_track_origins() && !OriginIsValid(origin)) { 217 Printf( 218 " ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin " 219 "tracking.\n This could still be a bug in your code, too!\n", 220 origin); 221 } 222} 223 224void UnpoisonParam(uptr n) { 225 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 226} 227 228// Backup MSan runtime TLS state. 229// Implementation must be async-signal-safe. 230// Instances of this class may live on the signal handler stack, and data size 231// may be an issue. 232void ScopedThreadLocalStateBackup::Backup() { 233 va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls; 234} 235 236void ScopedThreadLocalStateBackup::Restore() { 237 // A lame implementation that only keeps essential state and resets the rest. 238 __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls; 239 240 internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls)); 241 internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls)); 242 internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls)); 243 244 if (__msan_get_track_origins()) { 245 internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_tls)); 246 internal_memset(__msan_param_origin_tls, 0, 247 sizeof(__msan_param_origin_tls)); 248 } 249} 250 251void UnpoisonThreadLocalState() { 252} 253 254const char *GetOriginDescrIfStack(u32 id, uptr *pc) { 255 if ((id >> 31) == 0) return 0; 256 id &= (1U << 31) - 1; 257 CHECK_LT(id, kNumStackOriginDescrs); 258 if (pc) *pc = StackOriginPC[id]; 259 return StackOriginDescr[id]; 260} 261 262} // namespace __msan 263 264// Interface. 265 266using namespace __msan; 267 268void __msan_warning() { 269 GET_CALLER_PC_BP_SP; 270 (void)sp; 271 PrintWarning(pc, bp); 272 if (__msan::flags()->halt_on_error) { 273 Printf("Exiting\n"); 274 Die(); 275 } 276} 277 278void __msan_warning_noreturn() { 279 GET_CALLER_PC_BP_SP; 280 (void)sp; 281 PrintWarning(pc, bp); 282 Printf("Exiting\n"); 283 Die(); 284} 285 286void __msan_init() { 287 if (msan_inited) return; 288 msan_init_is_running = 1; 289 SanitizerToolName = "MemorySanitizer"; 290 291 SetDieCallback(MsanDie); 292 InitTlsSize(); 293 294 const char *msan_options = GetEnv("MSAN_OPTIONS"); 295 InitializeFlags(&msan_flags, msan_options); 296 __sanitizer_set_report_path(common_flags()->log_path); 297 298 InitializeInterceptors(); 299 InstallAtExitHandler(); // Needs __cxa_atexit interceptor. 300 301 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 302 ReplaceOperatorsNewAndDelete(); 303 if (StackSizeIsUnlimited()) { 304 if (common_flags()->verbosity) 305 Printf("Unlimited stack, doing reexec\n"); 306 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 307 // well, the program could have been run with unlimited stack for a reason. 308 SetStackSizeLimitInBytes(32 * 1024 * 1024); 309 ReExec(); 310 } 311 312 if (common_flags()->verbosity) 313 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 314 315 msan_running_under_dr = IsRunningUnderDr(); 316 __msan_clear_on_return(); 317 if (__msan_get_track_origins() && common_flags()->verbosity > 0) 318 Printf("msan_track_origins\n"); 319 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 320 __msan_get_track_origins())) { 321 // FIXME: prot1 = false is only required when running under DR. 322 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 323 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 324 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 325 Printf("FATAL: If running under GDB, try " 326 "'set disable-randomization off'.\n"); 327 DumpProcessMap(); 328 Die(); 329 } 330 331 const char *external_symbolizer = common_flags()->external_symbolizer_path; 332 bool external_symbolizer_started = 333 Symbolizer::Init(external_symbolizer)->IsExternalAvailable(); 334 if (external_symbolizer && external_symbolizer[0]) { 335 CHECK(external_symbolizer_started); 336 } 337 Symbolizer::Get()->AddHooks(EnterSymbolizer, ExitSymbolizer); 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 if (!MEM_IS_APP(x)) { 373 Printf("Not a valid application address: %p\n", x); 374 return; 375 } 376 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 377 u32 *o = (u32*)MEM_TO_ORIGIN(x); 378 for (uptr i = 0; i < size; i++) { 379 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 380 } 381 Printf("\n"); 382 if (__msan_get_track_origins()) { 383 for (uptr i = 0; i < size / 4; i++) { 384 Printf(" o: %x ", o[i]); 385 } 386 Printf("\n"); 387 } 388} 389 390void __msan_print_param_shadow() { 391 for (int i = 0; i < 16; i++) { 392 Printf("#%d:%zx ", i, __msan_param_tls[i]); 393 } 394 Printf("\n"); 395} 396 397sptr __msan_test_shadow(const void *x, uptr size) { 398 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 399 for (uptr i = 0; i < size; ++i) 400 if (s[i]) 401 return i; 402 return -1; 403} 404 405int __msan_set_poison_in_malloc(int do_poison) { 406 int old = flags()->poison_in_malloc; 407 flags()->poison_in_malloc = do_poison; 408 return old; 409} 410 411int __msan_has_dynamic_component() { 412 return msan_running_under_dr; 413} 414 415NOINLINE 416void __msan_clear_on_return() { 417 __msan_param_tls[0] = 0; 418} 419 420static void* get_tls_base() { 421 u64 p; 422 asm("mov %%fs:0, %0" 423 : "=r"(p) ::); 424 return (void*)p; 425} 426 427int __msan_get_retval_tls_offset() { 428 // volatile here is needed to avoid UB, because the compiler thinks that we 429 // are doing address arithmetics on unrelated pointers, and takes some 430 // shortcuts 431 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 432 volatile sptr tls_base_p = (sptr)get_tls_base(); 433 return retval_tls_p - tls_base_p; 434} 435 436int __msan_get_param_tls_offset() { 437 // volatile here is needed to avoid UB, because the compiler thinks that we 438 // are doing address arithmetics on unrelated pointers, and takes some 439 // shortcuts 440 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 441 volatile sptr tls_base_p = (sptr)get_tls_base(); 442 return param_tls_p - tls_base_p; 443} 444 445void __msan_partial_poison(const void* data, void* shadow, uptr size) { 446 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 447} 448 449void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 450 internal_memcpy(dst, src, size); 451 __msan_unpoison(dst, size); 452} 453 454void __msan_set_origin(const void *a, uptr size, u32 origin) { 455 // Origin mapping is 4 bytes per 4 bytes of application memory. 456 // Here we extend the range such that its left and right bounds are both 457 // 4 byte aligned. 458 if (!__msan_get_track_origins()) return; 459 uptr x = MEM_TO_ORIGIN((uptr)a); 460 uptr beg = x & ~3UL; // align down. 461 uptr end = (x + size + 3) & ~3UL; // align up. 462 u64 origin64 = ((u64)origin << 32) | origin; 463 // This is like memset, but the value is 32-bit. We unroll by 2 two write 464 // 64-bits at once. May want to unroll further to get 128-bit stores. 465 if (beg & 7ULL) { 466 *(u32*)beg = origin; 467 beg += 4; 468 } 469 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 470 *(u64*)addr = origin64; 471 if (end & 7ULL) 472 *(u32*)(end - 4) = origin; 473} 474 475// 'descr' is created at compile time and contains '----' in the beginning. 476// When we see descr for the first time we replace '----' with a uniq id 477// and set the origin to (id | (31-th bit)). 478void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 479 __msan_set_alloca_origin4(a, size, descr, 0); 480} 481 482void __msan_set_alloca_origin4(void *a, uptr size, const char *descr, uptr pc) { 483 static const u32 dash = '-'; 484 static const u32 first_timer = 485 dash + (dash << 8) + (dash << 16) + (dash << 24); 486 u32 *id_ptr = (u32*)descr; 487 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 488 u32 id = *id_ptr; 489 if (id == first_timer) { 490 id = atomic_fetch_add(&NumStackOriginDescrs, 491 1, memory_order_relaxed); 492 *id_ptr = id; 493 CHECK_LT(id, kNumStackOriginDescrs); 494 StackOriginDescr[id] = descr + 4; 495 StackOriginPC[id] = pc; 496 if (print) 497 Printf("First time: id=%d %s %p \n", id, descr + 4, pc); 498 } 499 id |= 1U << 31; 500 if (print) 501 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 502 __msan_set_origin(a, size, id); 503} 504 505const char *__msan_get_origin_descr_if_stack(u32 id) { 506 return GetOriginDescrIfStack(id, 0); 507} 508 509u32 __msan_get_origin(const void *a) { 510 if (!__msan_get_track_origins()) return 0; 511 uptr x = (uptr)a; 512 uptr aligned = x & ~3ULL; 513 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 514 return *(u32*)origin_ptr; 515} 516 517u32 __msan_get_umr_origin() { 518 return __msan_origin_tls; 519} 520 521u16 __sanitizer_unaligned_load16(const uu16 *p) { 522 __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); 523 if (__msan_get_track_origins()) 524 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 525 return *p; 526} 527u32 __sanitizer_unaligned_load32(const uu32 *p) { 528 __msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); 529 if (__msan_get_track_origins()) 530 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 531 return *p; 532} 533u64 __sanitizer_unaligned_load64(const uu64 *p) { 534 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); 535 if (__msan_get_track_origins()) 536 __msan_retval_origin_tls = *(uu32 *)MEM_TO_ORIGIN((uptr)p); 537 return *p; 538} 539void __sanitizer_unaligned_store16(uu16 *p, u16 x) { 540 *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 541 if (__msan_get_track_origins()) 542 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 543 *p = x; 544} 545void __sanitizer_unaligned_store32(uu32 *p, u32 x) { 546 *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 547 if (__msan_get_track_origins()) 548 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 549 *p = x; 550} 551void __sanitizer_unaligned_store64(uu64 *p, u64 x) { 552 *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 553 if (__msan_get_track_origins()) 554 *(uu32 *)MEM_TO_ORIGIN((uptr)p) = __msan_param_origin_tls[1]; 555 *p = x; 556} 557 558#if !SANITIZER_SUPPORTS_WEAK_HOOKS 559extern "C" { 560SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE 561const char* __msan_default_options() { return ""; } 562} // extern "C" 563#endif 564 565