msan.cc revision cfc29de659f3abbb9273fb0fb1c9a3cd5400c81b
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->verbosity, "verbosity"); 133 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 134 135 // keep_going is an old name for halt_on_error, 136 // and it has inverse meaning. 137 f->halt_on_error = !f->halt_on_error; 138 ParseFlag(str, &f->halt_on_error, "keep_going"); 139 f->halt_on_error = !f->halt_on_error; 140 ParseFlag(str, &f->halt_on_error, "halt_on_error"); 141} 142 143static void InitializeFlags(Flags *f, const char *options) { 144 CommonFlags *cf = common_flags(); 145 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 146 cf->strip_path_prefix = ""; 147 cf->fast_unwind_on_fatal = false; 148 cf->fast_unwind_on_malloc = true; 149 cf->malloc_context_size = 20; 150 cf->handle_ioctl = true; 151 cf->log_path = 0; 152 153 internal_memset(f, 0, sizeof(*f)); 154 f->poison_heap_with_zeroes = false; 155 f->poison_stack_with_zeroes = false; 156 f->poison_in_malloc = true; 157 f->poison_in_free = true; 158 f->exit_code = 77; 159 f->report_umrs = true; 160 f->verbosity = 0; 161 f->wrap_signals = true; 162 f->halt_on_error = !&__msan_keep_going; 163 164 // Override from user-specified string. 165 if (__msan_default_options) 166 ParseFlagsFromString(f, __msan_default_options()); 167 ParseFlagsFromString(f, options); 168} 169 170static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 171 if (__msan_stack_bounds.stack_top == 0) { 172 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 173 // realloc -> GetStackTrace). 174 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 175 GetThreadStackTopAndBottom(/* at_initialization */false, 176 &__msan_stack_bounds.stack_top, 177 &__msan_stack_bounds.stack_bottom); 178 } 179 *stack_top = __msan_stack_bounds.stack_top; 180 *stack_bottom = __msan_stack_bounds.stack_bottom; 181} 182 183void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 184 bool fast) { 185 if (!fast) { 186 // Block reports from our interceptors during _Unwind_Backtrace. 187 SymbolizerScope sym_scope; 188 return stack->SlowUnwindStack(pc, max_s); 189 } 190 191 uptr stack_top, stack_bottom; 192 GetCurrentStackBounds(&stack_top, &stack_bottom); 193 stack->size = 0; 194 stack->trace[0] = pc; 195 stack->max_size = max_s; 196 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); 197} 198 199void PrintWarning(uptr pc, uptr bp) { 200 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 201} 202 203bool OriginIsValid(u32 origin) { 204 return origin != 0 && origin != (u32)-1; 205} 206 207void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 208 if (msan_expect_umr) { 209 // Printf("Expected UMR\n"); 210 __msan_origin_tls = origin; 211 msan_expected_umr_found = 1; 212 return; 213 } 214 215 ++msan_report_count; 216 217 StackTrace stack; 218 GetStackTrace(&stack, kStackTraceMax, pc, bp, 219 common_flags()->fast_unwind_on_fatal); 220 221 u32 report_origin = 222 (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; 223 ReportUMR(&stack, report_origin); 224 225 if (__msan_get_track_origins() && !OriginIsValid(origin)) { 226 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 227 "please report to MemorySanitizer developers.\n", 228 origin); 229 } 230} 231 232void UnpoisonParam(uptr n) { 233 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 234} 235 236// Backup MSan runtime TLS state. 237// Implementation must be async-signal-safe. 238// Instances of this class may live on the signal handler stack, and data size 239// may be an issue. 240void ScopedThreadLocalStateBackup::Backup() { 241 va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls; 242} 243 244void ScopedThreadLocalStateBackup::Restore() { 245 // A lame implementation that only keeps essential state and resets the rest. 246 __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls; 247 248 internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls)); 249 internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls)); 250 internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls)); 251 252 if (__msan_get_track_origins()) { 253 internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_tls)); 254 internal_memset(__msan_param_origin_tls, 0, 255 sizeof(__msan_param_origin_tls)); 256 } 257} 258 259void UnpoisonThreadLocalState() { 260} 261 262const char *GetOriginDescrIfStack(u32 id, uptr *pc) { 263 if ((id >> 31) == 0) return 0; 264 id &= (1U << 31) - 1; 265 CHECK_LT(id, kNumStackOriginDescrs); 266 if (pc) *pc = StackOriginPC[id]; 267 return StackOriginDescr[id]; 268} 269 270} // namespace __msan 271 272// Interface. 273 274using namespace __msan; 275 276void __msan_warning() { 277 GET_CALLER_PC_BP_SP; 278 (void)sp; 279 PrintWarning(pc, bp); 280 if (__msan::flags()->halt_on_error) { 281 Printf("Exiting\n"); 282 Die(); 283 } 284} 285 286void __msan_warning_noreturn() { 287 GET_CALLER_PC_BP_SP; 288 (void)sp; 289 PrintWarning(pc, bp); 290 Printf("Exiting\n"); 291 Die(); 292} 293 294void __msan_init() { 295 if (msan_inited) return; 296 msan_init_is_running = 1; 297 SanitizerToolName = "MemorySanitizer"; 298 299 SetDieCallback(MsanDie); 300 InitTlsSize(); 301 InitializeInterceptors(); 302 InstallAtExitHandler(); // Needs __cxa_atexit interceptor. 303 304 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 305 ReplaceOperatorsNewAndDelete(); 306 const char *msan_options = GetEnv("MSAN_OPTIONS"); 307 InitializeFlags(&msan_flags, msan_options); 308 __sanitizer_set_report_path(common_flags()->log_path); 309 if (StackSizeIsUnlimited()) { 310 if (flags()->verbosity) 311 Printf("Unlimited stack, doing reexec\n"); 312 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 313 // well, the program could have been run with unlimited stack for a reason. 314 SetStackSizeLimitInBytes(32 * 1024 * 1024); 315 ReExec(); 316 } 317 318 if (flags()->verbosity) 319 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 320 321 msan_running_under_dr = IsRunningUnderDr(); 322 __msan_clear_on_return(); 323 if (__msan_get_track_origins() && flags()->verbosity > 0) 324 Printf("msan_track_origins\n"); 325 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 326 __msan_get_track_origins())) { 327 // FIXME: prot1 = false is only required when running under DR. 328 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 329 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 330 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 331 Printf("FATAL: If running under GDB, try " 332 "'set disable-randomization off'.\n"); 333 DumpProcessMap(); 334 Die(); 335 } 336 337 const char *external_symbolizer = common_flags()->external_symbolizer_path; 338 bool symbolizer_started = 339 getSymbolizer()->InitializeExternal(external_symbolizer); 340 if (external_symbolizer && external_symbolizer[0]) { 341 CHECK(symbolizer_started); 342 } 343 344 GetThreadStackTopAndBottom(/* at_initialization */true, 345 &__msan_stack_bounds.stack_top, 346 &__msan_stack_bounds.stack_bottom); 347 if (flags()->verbosity) 348 Printf("MemorySanitizer init done\n"); 349 msan_init_is_running = 0; 350 msan_inited = 1; 351} 352 353void __msan_set_exit_code(int exit_code) { 354 flags()->exit_code = exit_code; 355} 356 357void __msan_set_keep_going(int keep_going) { 358 flags()->halt_on_error = !keep_going; 359} 360 361void __msan_set_expect_umr(int expect_umr) { 362 if (expect_umr) { 363 msan_expected_umr_found = 0; 364 } else if (!msan_expected_umr_found) { 365 GET_CALLER_PC_BP_SP; 366 (void)sp; 367 StackTrace stack; 368 GetStackTrace(&stack, kStackTraceMax, pc, bp, 369 common_flags()->fast_unwind_on_fatal); 370 ReportExpectedUMRNotFound(&stack); 371 Die(); 372 } 373 msan_expect_umr = expect_umr; 374} 375 376void __msan_print_shadow(const void *x, uptr size) { 377 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 378 u32 *o = (u32*)MEM_TO_ORIGIN(x); 379 for (uptr i = 0; i < size; i++) { 380 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 381 } 382 Printf("\n"); 383 if (__msan_get_track_origins()) { 384 for (uptr i = 0; i < size / 4; i++) { 385 Printf(" o: %x ", o[i]); 386 } 387 Printf("\n"); 388 } 389} 390 391void __msan_print_param_shadow() { 392 for (int i = 0; i < 16; i++) { 393 Printf("#%d:%zx ", i, __msan_param_tls[i]); 394 } 395 Printf("\n"); 396} 397 398sptr __msan_test_shadow(const void *x, uptr size) { 399 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 400 for (uptr i = 0; i < size; ++i) 401 if (s[i]) 402 return i; 403 return -1; 404} 405 406int __msan_set_poison_in_malloc(int do_poison) { 407 int old = flags()->poison_in_malloc; 408 flags()->poison_in_malloc = do_poison; 409 return old; 410} 411 412int __msan_has_dynamic_component() { 413 return msan_running_under_dr; 414} 415 416NOINLINE 417void __msan_clear_on_return() { 418 __msan_param_tls[0] = 0; 419} 420 421static void* get_tls_base() { 422 u64 p; 423 asm("mov %%fs:0, %0" 424 : "=r"(p) ::); 425 return (void*)p; 426} 427 428int __msan_get_retval_tls_offset() { 429 // volatile here is needed to avoid UB, because the compiler thinks that we 430 // are doing address arithmetics on unrelated pointers, and takes some 431 // shortcuts 432 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 433 volatile sptr tls_base_p = (sptr)get_tls_base(); 434 return retval_tls_p - tls_base_p; 435} 436 437int __msan_get_param_tls_offset() { 438 // volatile here is needed to avoid UB, because the compiler thinks that we 439 // are doing address arithmetics on unrelated pointers, and takes some 440 // shortcuts 441 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 442 volatile sptr tls_base_p = (sptr)get_tls_base(); 443 return param_tls_p - tls_base_p; 444} 445 446void __msan_partial_poison(const void* data, void* shadow, uptr size) { 447 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 448} 449 450void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 451 internal_memcpy(dst, src, size); 452 __msan_unpoison(dst, size); 453} 454 455void __msan_set_origin(const void *a, uptr size, u32 origin) { 456 // Origin mapping is 4 bytes per 4 bytes of application memory. 457 // Here we extend the range such that its left and right bounds are both 458 // 4 byte aligned. 459 if (!__msan_get_track_origins()) return; 460 uptr x = MEM_TO_ORIGIN((uptr)a); 461 uptr beg = x & ~3UL; // align down. 462 uptr end = (x + size + 3) & ~3UL; // align up. 463 u64 origin64 = ((u64)origin << 32) | origin; 464 // This is like memset, but the value is 32-bit. We unroll by 2 two write 465 // 64-bits at once. May want to unroll further to get 128-bit stores. 466 if (beg & 7ULL) { 467 *(u32*)beg = origin; 468 beg += 4; 469 } 470 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 471 *(u64*)addr = origin64; 472 if (end & 7ULL) 473 *(u32*)(end - 4) = origin; 474} 475 476// 'descr' is created at compile time and contains '----' in the beginning. 477// When we see descr for the first time we replace '----' with a uniq id 478// and set the origin to (id | (31-th bit)). 479void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 480 __msan_set_alloca_origin4(a, size, descr, 0); 481} 482 483void __msan_set_alloca_origin4(void *a, uptr size, const char *descr, uptr pc) { 484 static const u32 dash = '-'; 485 static const u32 first_timer = 486 dash + (dash << 8) + (dash << 16) + (dash << 24); 487 u32 *id_ptr = (u32*)descr; 488 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 489 u32 id = *id_ptr; 490 if (id == first_timer) { 491 id = atomic_fetch_add(&NumStackOriginDescrs, 492 1, memory_order_relaxed); 493 *id_ptr = id; 494 CHECK_LT(id, kNumStackOriginDescrs); 495 StackOriginDescr[id] = descr + 4; 496 StackOriginPC[id] = pc; 497 if (print) 498 Printf("First time: id=%d %s %p \n", id, descr + 4, pc); 499 } 500 id |= 1U << 31; 501 if (print) 502 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 503 __msan_set_origin(a, size, id); 504} 505 506const char *__msan_get_origin_descr_if_stack(u32 id) { 507 return GetOriginDescrIfStack(id, 0); 508} 509 510u32 __msan_get_origin(const void *a) { 511 if (!__msan_get_track_origins()) return 0; 512 uptr x = (uptr)a; 513 uptr aligned = x & ~3ULL; 514 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 515 return *(u32*)origin_ptr; 516} 517 518u32 __msan_get_umr_origin() { 519 return __msan_origin_tls; 520} 521 522u16 __sanitizer_unaligned_load16(const uu16 *p) { 523 __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); 524 return *p; 525} 526u32 __sanitizer_unaligned_load32(const uu32 *p) { 527 __msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); 528 return *p; 529} 530u64 __sanitizer_unaligned_load64(const uu64 *p) { 531 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); 532 return *p; 533} 534void __sanitizer_unaligned_store16(uu16 *p, u16 x) { 535 *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 536 *p = x; 537} 538void __sanitizer_unaligned_store32(uu32 *p, u32 x) { 539 *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 540 *p = x; 541} 542void __sanitizer_unaligned_store64(uu64 *p, u64 x) { 543 *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 544 *p = x; 545} 546 547#if !SANITIZER_SUPPORTS_WEAK_HOOKS 548extern "C" { 549SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE 550const char* __msan_default_options() { return ""; } 551} // extern "C" 552#endif 553 554