msan.cc revision 064da32709c8bf81283062abc04cf6e88e6c075d
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->FastUnwindStack(pc, bp, stack_top, stack_bottom, max_s); 194} 195 196void PrintWarning(uptr pc, uptr bp) { 197 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 198} 199 200bool OriginIsValid(u32 origin) { 201 return origin != 0 && origin != (u32)-1; 202} 203 204void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 205 if (msan_expect_umr) { 206 // Printf("Expected UMR\n"); 207 __msan_origin_tls = origin; 208 msan_expected_umr_found = 1; 209 return; 210 } 211 212 ++msan_report_count; 213 214 StackTrace stack; 215 GetStackTrace(&stack, kStackTraceMax, pc, bp, 216 common_flags()->fast_unwind_on_fatal); 217 218 u32 report_origin = 219 (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; 220 ReportUMR(&stack, report_origin); 221 222 if (__msan_get_track_origins() && !OriginIsValid(origin)) { 223 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 224 "please report to MemorySanitizer developers.\n", 225 origin); 226 } 227} 228 229void UnpoisonParam(uptr n) { 230 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 231} 232 233// Backup MSan runtime TLS state. 234// Implementation must be async-signal-safe. 235// Instances of this class may live on the signal handler stack, and data size 236// may be an issue. 237void ScopedThreadLocalStateBackup::Backup() { 238 va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls; 239} 240 241void ScopedThreadLocalStateBackup::Restore() { 242 // A lame implementation that only keeps essential state and resets the rest. 243 __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls; 244 245 internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls)); 246 internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls)); 247 internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls)); 248 249 if (__msan_get_track_origins()) { 250 internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_tls)); 251 internal_memset(__msan_param_origin_tls, 0, 252 sizeof(__msan_param_origin_tls)); 253 } 254} 255 256void UnpoisonThreadLocalState() { 257} 258 259const char *GetOriginDescrIfStack(u32 id, uptr *pc) { 260 if ((id >> 31) == 0) return 0; 261 id &= (1U << 31) - 1; 262 CHECK_LT(id, kNumStackOriginDescrs); 263 if (pc) *pc = StackOriginPC[id]; 264 return StackOriginDescr[id]; 265} 266 267} // namespace __msan 268 269// Interface. 270 271using namespace __msan; 272 273void __msan_warning() { 274 GET_CALLER_PC_BP_SP; 275 (void)sp; 276 PrintWarning(pc, bp); 277 if (__msan::flags()->halt_on_error) { 278 Printf("Exiting\n"); 279 Die(); 280 } 281} 282 283void __msan_warning_noreturn() { 284 GET_CALLER_PC_BP_SP; 285 (void)sp; 286 PrintWarning(pc, bp); 287 Printf("Exiting\n"); 288 Die(); 289} 290 291void __msan_init() { 292 if (msan_inited) return; 293 msan_init_is_running = 1; 294 SanitizerToolName = "MemorySanitizer"; 295 296 SetDieCallback(MsanDie); 297 InitTlsSize(); 298 InitializeInterceptors(); 299 InstallAtExitHandler(); // Needs __cxa_atexit interceptor. 300 301 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 302 ReplaceOperatorsNewAndDelete(); 303 const char *msan_options = GetEnv("MSAN_OPTIONS"); 304 InitializeFlags(&msan_flags, msan_options); 305 __sanitizer_set_report_path(common_flags()->log_path); 306 if (StackSizeIsUnlimited()) { 307 if (flags()->verbosity) 308 Printf("Unlimited stack, doing reexec\n"); 309 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 310 // well, the program could have been run with unlimited stack for a reason. 311 SetStackSizeLimitInBytes(32 * 1024 * 1024); 312 ReExec(); 313 } 314 315 if (flags()->verbosity) 316 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 317 318 msan_running_under_dr = IsRunningUnderDr(); 319 __msan_clear_on_return(); 320 if (__msan_get_track_origins() && flags()->verbosity > 0) 321 Printf("msan_track_origins\n"); 322 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 323 __msan_get_track_origins())) { 324 // FIXME: prot1 = false is only required when running under DR. 325 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 326 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 327 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 328 Printf("FATAL: If running under GDB, try " 329 "'set disable-randomization off'.\n"); 330 DumpProcessMap(); 331 Die(); 332 } 333 334 const char *external_symbolizer = common_flags()->external_symbolizer_path; 335 bool symbolizer_started = 336 getSymbolizer()->InitializeExternal(external_symbolizer); 337 if (external_symbolizer && external_symbolizer[0]) { 338 CHECK(symbolizer_started); 339 } 340 341 GetThreadStackTopAndBottom(/* at_initialization */true, 342 &__msan_stack_bounds.stack_top, 343 &__msan_stack_bounds.stack_bottom); 344 if (flags()->verbosity) 345 Printf("MemorySanitizer init done\n"); 346 msan_init_is_running = 0; 347 msan_inited = 1; 348} 349 350void __msan_set_exit_code(int exit_code) { 351 flags()->exit_code = exit_code; 352} 353 354void __msan_set_keep_going(int keep_going) { 355 flags()->halt_on_error = !keep_going; 356} 357 358void __msan_set_expect_umr(int expect_umr) { 359 if (expect_umr) { 360 msan_expected_umr_found = 0; 361 } else if (!msan_expected_umr_found) { 362 GET_CALLER_PC_BP_SP; 363 (void)sp; 364 StackTrace stack; 365 GetStackTrace(&stack, kStackTraceMax, pc, bp, 366 common_flags()->fast_unwind_on_fatal); 367 ReportExpectedUMRNotFound(&stack); 368 Die(); 369 } 370 msan_expect_umr = expect_umr; 371} 372 373void __msan_print_shadow(const void *x, uptr size) { 374 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 375 u32 *o = (u32*)MEM_TO_ORIGIN(x); 376 for (uptr i = 0; i < size; i++) { 377 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 378 } 379 Printf("\n"); 380 if (__msan_get_track_origins()) { 381 for (uptr i = 0; i < size / 4; i++) { 382 Printf(" o: %x ", o[i]); 383 } 384 Printf("\n"); 385 } 386} 387 388void __msan_print_param_shadow() { 389 for (int i = 0; i < 16; i++) { 390 Printf("#%d:%zx ", i, __msan_param_tls[i]); 391 } 392 Printf("\n"); 393} 394 395sptr __msan_test_shadow(const void *x, uptr size) { 396 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 397 for (uptr i = 0; i < size; ++i) 398 if (s[i]) 399 return i; 400 return -1; 401} 402 403int __msan_set_poison_in_malloc(int do_poison) { 404 int old = flags()->poison_in_malloc; 405 flags()->poison_in_malloc = do_poison; 406 return old; 407} 408 409int __msan_has_dynamic_component() { 410 return msan_running_under_dr; 411} 412 413NOINLINE 414void __msan_clear_on_return() { 415 __msan_param_tls[0] = 0; 416} 417 418static void* get_tls_base() { 419 u64 p; 420 asm("mov %%fs:0, %0" 421 : "=r"(p) ::); 422 return (void*)p; 423} 424 425int __msan_get_retval_tls_offset() { 426 // volatile here is needed to avoid UB, because the compiler thinks that we 427 // are doing address arithmetics on unrelated pointers, and takes some 428 // shortcuts 429 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 430 volatile sptr tls_base_p = (sptr)get_tls_base(); 431 return retval_tls_p - tls_base_p; 432} 433 434int __msan_get_param_tls_offset() { 435 // volatile here is needed to avoid UB, because the compiler thinks that we 436 // are doing address arithmetics on unrelated pointers, and takes some 437 // shortcuts 438 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 439 volatile sptr tls_base_p = (sptr)get_tls_base(); 440 return param_tls_p - tls_base_p; 441} 442 443void __msan_partial_poison(const void* data, void* shadow, uptr size) { 444 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 445} 446 447void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 448 internal_memcpy(dst, src, size); 449 __msan_unpoison(dst, size); 450} 451 452void __msan_set_origin(const void *a, uptr size, u32 origin) { 453 // Origin mapping is 4 bytes per 4 bytes of application memory. 454 // Here we extend the range such that its left and right bounds are both 455 // 4 byte aligned. 456 if (!__msan_get_track_origins()) return; 457 uptr x = MEM_TO_ORIGIN((uptr)a); 458 uptr beg = x & ~3UL; // align down. 459 uptr end = (x + size + 3) & ~3UL; // align up. 460 u64 origin64 = ((u64)origin << 32) | origin; 461 // This is like memset, but the value is 32-bit. We unroll by 2 two write 462 // 64-bits at once. May want to unroll further to get 128-bit stores. 463 if (beg & 7ULL) { 464 *(u32*)beg = origin; 465 beg += 4; 466 } 467 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 468 *(u64*)addr = origin64; 469 if (end & 7ULL) 470 *(u32*)(end - 4) = origin; 471} 472 473// 'descr' is created at compile time and contains '----' in the beginning. 474// When we see descr for the first time we replace '----' with a uniq id 475// and set the origin to (id | (31-th bit)). 476void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 477 __msan_set_alloca_origin4(a, size, descr, 0); 478} 479 480void __msan_set_alloca_origin4(void *a, uptr size, const char *descr, uptr pc) { 481 static const u32 dash = '-'; 482 static const u32 first_timer = 483 dash + (dash << 8) + (dash << 16) + (dash << 24); 484 u32 *id_ptr = (u32*)descr; 485 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 486 u32 id = *id_ptr; 487 if (id == first_timer) { 488 id = atomic_fetch_add(&NumStackOriginDescrs, 489 1, memory_order_relaxed); 490 *id_ptr = id; 491 CHECK_LT(id, kNumStackOriginDescrs); 492 StackOriginDescr[id] = descr + 4; 493 StackOriginPC[id] = pc; 494 if (print) 495 Printf("First time: id=%d %s %p \n", id, descr + 4, pc); 496 } 497 id |= 1U << 31; 498 if (print) 499 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 500 __msan_set_origin(a, size, id); 501} 502 503const char *__msan_get_origin_descr_if_stack(u32 id) { 504 return GetOriginDescrIfStack(id, 0); 505} 506 507u32 __msan_get_origin(const void *a) { 508 if (!__msan_get_track_origins()) return 0; 509 uptr x = (uptr)a; 510 uptr aligned = x & ~3ULL; 511 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 512 return *(u32*)origin_ptr; 513} 514 515u32 __msan_get_umr_origin() { 516 return __msan_origin_tls; 517} 518 519u16 __sanitizer_unaligned_load16(const uu16 *p) { 520 __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((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 return *p; 526} 527u64 __sanitizer_unaligned_load64(const uu64 *p) { 528 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); 529 return *p; 530} 531void __sanitizer_unaligned_store16(uu16 *p, u16 x) { 532 *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 533 *p = x; 534} 535void __sanitizer_unaligned_store32(uu32 *p, u32 x) { 536 *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 537 *p = x; 538} 539void __sanitizer_unaligned_store64(uu64 *p, u64 x) { 540 *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 541 *p = x; 542} 543 544#if !SANITIZER_SUPPORTS_WEAK_HOOKS 545extern "C" { 546SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE 547const char* __msan_default_options() { return ""; } 548} // extern "C" 549#endif 550 551