msan.cc revision 68c016aea0b61f649b9d9ba65c7d7217e0c0f6cb
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 bool is_in_symbolizer; 62static THREADLOCAL bool 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 = true; } 91void ExitSymbolizer() { is_in_symbolizer = false; } 92bool IsInSymbolizer() { return is_in_symbolizer; } 93 94void EnterLoader() { is_in_loader = true; } 95void ExitLoader() { is_in_loader = false; } 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 atomic_uint32_t NumStackOriginDescrs; 118 119static void ParseFlagsFromString(Flags *f, const char *str) { 120 ParseCommonFlagsFromString(str); 121 ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); 122 ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); 123 ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); 124 ParseFlag(str, &f->exit_code, "exit_code"); 125 if (f->exit_code < 0 || f->exit_code > 127) { 126 Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); 127 Die(); 128 } 129 ParseFlag(str, &f->report_umrs, "report_umrs"); 130 ParseFlag(str, &f->verbosity, "verbosity"); 131 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 132 133 // keep_going is an old name for halt_on_error, 134 // and it has inverse meaning. 135 f->halt_on_error = !f->halt_on_error; 136 ParseFlag(str, &f->halt_on_error, "keep_going"); 137 f->halt_on_error = !f->halt_on_error; 138 ParseFlag(str, &f->halt_on_error, "halt_on_error"); 139} 140 141static void InitializeFlags(Flags *f, const char *options) { 142 CommonFlags *cf = common_flags(); 143 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 144 cf->strip_path_prefix = ""; 145 cf->fast_unwind_on_fatal = false; 146 cf->fast_unwind_on_malloc = true; 147 cf->malloc_context_size = 20; 148 cf->handle_ioctl = true; 149 cf->log_path = 0; 150 151 internal_memset(f, 0, sizeof(*f)); 152 f->poison_heap_with_zeroes = false; 153 f->poison_stack_with_zeroes = false; 154 f->poison_in_malloc = true; 155 f->exit_code = 77; 156 f->report_umrs = true; 157 f->verbosity = 0; 158 f->wrap_signals = true; 159 f->halt_on_error = !&__msan_keep_going; 160 161 // Override from user-specified string. 162 if (__msan_default_options) 163 ParseFlagsFromString(f, __msan_default_options()); 164 ParseFlagsFromString(f, options); 165} 166 167static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 168 if (__msan_stack_bounds.stack_top == 0) { 169 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 170 // realloc -> GetStackTrace). 171 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 172 GetThreadStackTopAndBottom(/* at_initialization */false, 173 &__msan_stack_bounds.stack_top, 174 &__msan_stack_bounds.stack_bottom); 175 } 176 *stack_top = __msan_stack_bounds.stack_top; 177 *stack_bottom = __msan_stack_bounds.stack_bottom; 178} 179 180void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 181 bool fast) { 182 if (!fast) { 183 // Block reports from our interceptors during _Unwind_Backtrace. 184 SymbolizerScope sym_scope; 185 return stack->SlowUnwindStack(pc, max_s); 186 } 187 188 uptr stack_top, stack_bottom; 189 GetCurrentStackBounds(&stack_top, &stack_bottom); 190 stack->size = 0; 191 stack->trace[0] = pc; 192 stack->max_size = max_s; 193 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); 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} 258 259} // namespace __msan 260 261// Interface. 262 263using namespace __msan; 264 265void __msan_warning() { 266 GET_CALLER_PC_BP_SP; 267 (void)sp; 268 PrintWarning(pc, bp); 269 if (__msan::flags()->halt_on_error) { 270 Printf("Exiting\n"); 271 Die(); 272 } 273} 274 275void __msan_warning_noreturn() { 276 GET_CALLER_PC_BP_SP; 277 (void)sp; 278 PrintWarning(pc, bp); 279 Printf("Exiting\n"); 280 Die(); 281} 282 283void __msan_init() { 284 if (msan_inited) return; 285 msan_init_is_running = 1; 286 SanitizerToolName = "MemorySanitizer"; 287 288 InstallAtExitHandler(); 289 SetDieCallback(MsanDie); 290 InitTlsSize(); 291 InitializeInterceptors(); 292 293 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 294 ReplaceOperatorsNewAndDelete(); 295 const char *msan_options = GetEnv("MSAN_OPTIONS"); 296 InitializeFlags(&msan_flags, msan_options); 297 __sanitizer_set_report_path(common_flags()->log_path); 298 if (StackSizeIsUnlimited()) { 299 if (flags()->verbosity) 300 Printf("Unlimited stack, doing reexec\n"); 301 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 302 // well, the program could have been run with unlimited stack for a reason. 303 SetStackSizeLimitInBytes(32 * 1024 * 1024); 304 ReExec(); 305 } 306 307 if (flags()->verbosity) 308 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 309 310 msan_running_under_dr = IsRunningUnderDr(); 311 __msan_clear_on_return(); 312 if (__msan_get_track_origins() && flags()->verbosity > 0) 313 Printf("msan_track_origins\n"); 314 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 315 __msan_get_track_origins())) { 316 // FIXME: prot1 = false is only required when running under DR. 317 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 318 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 319 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 320 Printf("FATAL: If running under GDB, try " 321 "'set disable-randomization off'.\n"); 322 DumpProcessMap(); 323 Die(); 324 } 325 326 const char *external_symbolizer = common_flags()->external_symbolizer_path; 327 bool symbolizer_started = InitializeExternalSymbolizer(external_symbolizer); 328 if (external_symbolizer && external_symbolizer[0]) { 329 CHECK(symbolizer_started); 330 } 331 332 GetThreadStackTopAndBottom(/* at_initialization */true, 333 &__msan_stack_bounds.stack_top, 334 &__msan_stack_bounds.stack_bottom); 335 if (flags()->verbosity) 336 Printf("MemorySanitizer init done\n"); 337 msan_init_is_running = 0; 338 msan_inited = 1; 339} 340 341void __msan_set_exit_code(int exit_code) { 342 flags()->exit_code = exit_code; 343} 344 345void __msan_set_keep_going(int keep_going) { 346 flags()->halt_on_error = !keep_going; 347} 348 349void __msan_set_expect_umr(int expect_umr) { 350 if (expect_umr) { 351 msan_expected_umr_found = 0; 352 } else if (!msan_expected_umr_found) { 353 GET_CALLER_PC_BP_SP; 354 (void)sp; 355 StackTrace stack; 356 GetStackTrace(&stack, kStackTraceMax, pc, bp, 357 common_flags()->fast_unwind_on_fatal); 358 ReportExpectedUMRNotFound(&stack); 359 Die(); 360 } 361 msan_expect_umr = expect_umr; 362} 363 364void __msan_print_shadow(const void *x, uptr size) { 365 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 366 u32 *o = (u32*)MEM_TO_ORIGIN(x); 367 for (uptr i = 0; i < size; i++) { 368 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 369 } 370 Printf("\n"); 371 if (__msan_get_track_origins()) { 372 for (uptr i = 0; i < size / 4; i++) { 373 Printf(" o: %x ", o[i]); 374 } 375 Printf("\n"); 376 } 377} 378 379void __msan_print_param_shadow() { 380 for (int i = 0; i < 16; i++) { 381 Printf("#%d:%zx ", i, __msan_param_tls[i]); 382 } 383 Printf("\n"); 384} 385 386sptr __msan_test_shadow(const void *x, uptr size) { 387 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 388 for (uptr i = 0; i < size; ++i) 389 if (s[i]) 390 return i; 391 return -1; 392} 393 394int __msan_set_poison_in_malloc(int do_poison) { 395 int old = flags()->poison_in_malloc; 396 flags()->poison_in_malloc = do_poison; 397 return old; 398} 399 400int __msan_has_dynamic_component() { 401 return msan_running_under_dr; 402} 403 404NOINLINE 405void __msan_clear_on_return() { 406 __msan_param_tls[0] = 0; 407} 408 409static void* get_tls_base() { 410 u64 p; 411 asm("mov %%fs:0, %0" 412 : "=r"(p) ::); 413 return (void*)p; 414} 415 416int __msan_get_retval_tls_offset() { 417 // volatile here is needed to avoid UB, because the compiler thinks that we 418 // are doing address arithmetics on unrelated pointers, and takes some 419 // shortcuts 420 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 421 volatile sptr tls_base_p = (sptr)get_tls_base(); 422 return retval_tls_p - tls_base_p; 423} 424 425int __msan_get_param_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 param_tls_p = (sptr)&__msan_param_tls; 430 volatile sptr tls_base_p = (sptr)get_tls_base(); 431 return param_tls_p - tls_base_p; 432} 433 434void __msan_partial_poison(const void* data, void* shadow, uptr size) { 435 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 436} 437 438void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 439 internal_memcpy(dst, src, size); 440 __msan_unpoison(dst, size); 441} 442 443void __msan_set_origin(const void *a, uptr size, u32 origin) { 444 // Origin mapping is 4 bytes per 4 bytes of application memory. 445 // Here we extend the range such that its left and right bounds are both 446 // 4 byte aligned. 447 if (!__msan_get_track_origins()) return; 448 uptr x = MEM_TO_ORIGIN((uptr)a); 449 uptr beg = x & ~3UL; // align down. 450 uptr end = (x + size + 3) & ~3UL; // align up. 451 u64 origin64 = ((u64)origin << 32) | origin; 452 // This is like memset, but the value is 32-bit. We unroll by 2 two write 453 // 64-bits at once. May want to unroll further to get 128-bit stores. 454 if (beg & 7ULL) { 455 *(u32*)beg = origin; 456 beg += 4; 457 } 458 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 459 *(u64*)addr = origin64; 460 if (end & 7ULL) 461 *(u32*)(end - 4) = origin; 462} 463 464// 'descr' is created at compile time and contains '----' in the beginning. 465// When we see descr for the first time we replace '----' with a uniq id 466// and set the origin to (id | (31-th bit)). 467void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 468 static const u32 dash = '-'; 469 static const u32 first_timer = 470 dash + (dash << 8) + (dash << 16) + (dash << 24); 471 u32 *id_ptr = (u32*)descr; 472 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 473 u32 id = *id_ptr; 474 if (id == first_timer) { 475 id = atomic_fetch_add(&NumStackOriginDescrs, 476 1, memory_order_relaxed); 477 *id_ptr = id; 478 CHECK_LT(id, kNumStackOriginDescrs); 479 StackOriginDescr[id] = descr + 4; 480 if (print) 481 Printf("First time: id=%d %s \n", id, descr + 4); 482 } 483 id |= 1U << 31; 484 if (print) 485 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 486 __msan_set_origin(a, size, id); 487} 488 489const char *__msan_get_origin_descr_if_stack(u32 id) { 490 if ((id >> 31) == 0) return 0; 491 id &= (1U << 31) - 1; 492 CHECK_LT(id, kNumStackOriginDescrs); 493 return StackOriginDescr[id]; 494} 495 496 497u32 __msan_get_origin(const void *a) { 498 if (!__msan_get_track_origins()) return 0; 499 uptr x = (uptr)a; 500 uptr aligned = x & ~3ULL; 501 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 502 return *(u32*)origin_ptr; 503} 504 505u32 __msan_get_umr_origin() { 506 return __msan_origin_tls; 507} 508 509u16 __sanitizer_unaligned_load16(const uu16 *p) { 510 __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); 511 return *p; 512} 513u32 __sanitizer_unaligned_load32(const uu32 *p) { 514 __msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); 515 return *p; 516} 517u64 __sanitizer_unaligned_load64(const uu64 *p) { 518 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); 519 return *p; 520} 521void __sanitizer_unaligned_store16(uu16 *p, u16 x) { 522 *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 523 *p = x; 524} 525void __sanitizer_unaligned_store32(uu32 *p, u32 x) { 526 *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 527 *p = x; 528} 529void __sanitizer_unaligned_store64(uu64 *p, u64 x) { 530 *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; 531 *p = x; 532} 533 534#if !SANITIZER_SUPPORTS_WEAK_HOOKS 535extern "C" { 536SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE 537const char* __msan_default_options() { return ""; } 538} // extern "C" 539#endif 540 541