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