msan.cc revision a879f10ee6aa04f6169d056ef2a9c39502fff290
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 70namespace __msan { 71 72static bool IsRunningUnderDr() { 73 bool result = false; 74 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 75 const sptr kBufSize = 4095; 76 char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__); 77 while (proc_maps.Next(/* start */0, /* end */0, /* file_offset */0, 78 filename, kBufSize, /* protection */0)) { 79 if (internal_strstr(filename, "libdynamorio") != 0) { 80 result = true; 81 break; 82 } 83 } 84 UnmapOrDie(filename, kBufSize); 85 return result; 86} 87 88void EnterSymbolizer() { is_in_symbolizer = true; } 89void ExitSymbolizer() { is_in_symbolizer = false; } 90bool IsInSymbolizer() { return is_in_symbolizer; } 91 92void EnterLoader() { is_in_loader = true; } 93void ExitLoader() { is_in_loader = false; } 94 95extern "C" { 96SANITIZER_INTERFACE_ATTRIBUTE 97bool __msan_is_in_loader() { return is_in_loader; } 98} 99 100static Flags msan_flags; 101 102Flags *flags() { 103 return &msan_flags; 104} 105 106int msan_inited = 0; 107bool msan_init_is_running; 108 109int msan_report_count = 0; 110 111// Array of stack origins. 112// FIXME: make it resizable. 113static const uptr kNumStackOriginDescrs = 1024 * 1024; 114static const char *StackOriginDescr[kNumStackOriginDescrs]; 115static atomic_uint32_t NumStackOriginDescrs; 116 117static void ParseFlagsFromString(Flags *f, const char *str) { 118 ParseCommonFlagsFromString(str); 119 ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); 120 ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); 121 ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); 122 ParseFlag(str, &f->exit_code, "exit_code"); 123 if (f->exit_code < 0 || f->exit_code > 127) { 124 Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); 125 f->exit_code = 1; 126 Die(); 127 } 128 ParseFlag(str, &f->report_umrs, "report_umrs"); 129 ParseFlag(str, &f->verbosity, "verbosity"); 130 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 131} 132 133static void InitializeFlags(Flags *f, const char *options) { 134 CommonFlags *cf = common_flags(); 135 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 136 cf->strip_path_prefix = ""; 137 cf->fast_unwind_on_fatal = false; 138 cf->fast_unwind_on_malloc = true; 139 cf->malloc_context_size = 20; 140 141 internal_memset(f, 0, sizeof(*f)); 142 f->poison_heap_with_zeroes = false; 143 f->poison_stack_with_zeroes = false; 144 f->poison_in_malloc = true; 145 f->exit_code = 77; 146 f->report_umrs = true; 147 f->verbosity = 0; 148 f->wrap_signals = true; 149 150 // Override from user-specified string. 151 if (__msan_default_options) 152 ParseFlagsFromString(f, __msan_default_options()); 153 ParseFlagsFromString(f, options); 154} 155 156static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 157 if (__msan_stack_bounds.stack_top == 0) { 158 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 159 // realloc -> GetStackTrace). 160 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 161 GetThreadStackTopAndBottom(/* at_initialization */false, 162 &__msan_stack_bounds.stack_top, 163 &__msan_stack_bounds.stack_bottom); 164 } 165 *stack_top = __msan_stack_bounds.stack_top; 166 *stack_bottom = __msan_stack_bounds.stack_bottom; 167} 168 169void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 170 bool fast) { 171 if (!fast) { 172 // Block reports from our interceptors during _Unwind_Backtrace. 173 SymbolizerScope sym_scope; 174 return stack->SlowUnwindStack(pc, max_s); 175 } 176 177 uptr stack_top, stack_bottom; 178 GetCurrentStackBounds(&stack_top, &stack_bottom); 179 stack->size = 0; 180 stack->trace[0] = pc; 181 stack->max_size = max_s; 182 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); 183} 184 185void PrintWarning(uptr pc, uptr bp) { 186 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 187} 188 189bool OriginIsValid(u32 origin) { 190 return origin != 0 && origin != (u32)-1; 191} 192 193void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 194 if (msan_expect_umr) { 195 // Printf("Expected UMR\n"); 196 __msan_origin_tls = origin; 197 msan_expected_umr_found = 1; 198 return; 199 } 200 201 ++msan_report_count; 202 203 StackTrace stack; 204 GetStackTrace(&stack, kStackTraceMax, pc, bp, 205 common_flags()->fast_unwind_on_fatal); 206 207 u32 report_origin = 208 (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; 209 ReportUMR(&stack, report_origin); 210 211 if (__msan_get_track_origins() && !OriginIsValid(origin)) { 212 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 213 "please report to MemorySanitizer developers.\n", 214 origin); 215 } 216} 217 218} // namespace __msan 219 220// Interface. 221 222using namespace __msan; 223 224void __msan_warning() { 225 GET_CALLER_PC_BP_SP; 226 (void)sp; 227 PrintWarning(pc, bp); 228} 229 230void __msan_warning_noreturn() { 231 GET_CALLER_PC_BP_SP; 232 (void)sp; 233 PrintWarning(pc, bp); 234 Printf("Exiting\n"); 235 Die(); 236} 237 238void __msan_init() { 239 if (msan_inited) return; 240 msan_init_is_running = 1; 241 SanitizerToolName = "MemorySanitizer"; 242 243 InstallAtExitHandler(); 244 SetDieCallback(MsanDie); 245 InitTlsSize(); 246 InitializeInterceptors(); 247 248 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 249 ReplaceOperatorsNewAndDelete(); 250 const char *msan_options = GetEnv("MSAN_OPTIONS"); 251 InitializeFlags(&msan_flags, msan_options); 252 if (StackSizeIsUnlimited()) { 253 if (flags()->verbosity) 254 Printf("Unlimited stack, doing reexec\n"); 255 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 256 // well, the program could have been run with unlimited stack for a reason. 257 SetStackSizeLimitInBytes(32 * 1024 * 1024); 258 ReExec(); 259 } 260 261 if (flags()->verbosity) 262 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 263 264 msan_running_under_dr = IsRunningUnderDr(); 265 __msan_clear_on_return(); 266 if (__msan_get_track_origins() && flags()->verbosity > 0) 267 Printf("msan_track_origins\n"); 268 if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, 269 __msan_get_track_origins())) { 270 // FIXME: prot1 = false is only required when running under DR. 271 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 272 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 273 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 274 Printf("FATAL: If running under GDB, try " 275 "'set disable-randomization off'.\n"); 276 DumpProcessMap(); 277 Die(); 278 } 279 280 const char *external_symbolizer = common_flags()->external_symbolizer_path; 281 if (external_symbolizer && external_symbolizer[0]) { 282 CHECK(InitializeExternalSymbolizer(external_symbolizer)); 283 } 284 285 GetThreadStackTopAndBottom(/* at_initialization */true, 286 &__msan_stack_bounds.stack_top, 287 &__msan_stack_bounds.stack_bottom); 288 if (flags()->verbosity) 289 Printf("MemorySanitizer init done\n"); 290 msan_init_is_running = 0; 291 msan_inited = 1; 292} 293 294void __msan_set_exit_code(int exit_code) { 295 flags()->exit_code = exit_code; 296} 297 298void __msan_set_expect_umr(int expect_umr) { 299 if (expect_umr) { 300 msan_expected_umr_found = 0; 301 } else if (!msan_expected_umr_found) { 302 GET_CALLER_PC_BP_SP; 303 (void)sp; 304 StackTrace stack; 305 GetStackTrace(&stack, kStackTraceMax, pc, bp, 306 common_flags()->fast_unwind_on_fatal); 307 ReportExpectedUMRNotFound(&stack); 308 Die(); 309 } 310 msan_expect_umr = expect_umr; 311} 312 313void __msan_print_shadow(const void *x, uptr size) { 314 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 315 u32 *o = (u32*)MEM_TO_ORIGIN(x); 316 for (uptr i = 0; i < size; i++) { 317 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 318 } 319 Printf("\n"); 320 if (__msan_get_track_origins()) { 321 for (uptr i = 0; i < size / 4; i++) { 322 Printf(" o: %x ", o[i]); 323 } 324 Printf("\n"); 325 } 326} 327 328void __msan_print_param_shadow() { 329 for (int i = 0; i < 16; i++) { 330 Printf("#%d:%zx ", i, __msan_param_tls[i]); 331 } 332 Printf("\n"); 333} 334 335void __msan_unpoison_param(uptr n) { 336 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 337} 338 339sptr __msan_test_shadow(const void *x, uptr size) { 340 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 341 for (uptr i = 0; i < size; ++i) 342 if (s[i]) 343 return i; 344 return -1; 345} 346 347int __msan_set_poison_in_malloc(int do_poison) { 348 int old = flags()->poison_in_malloc; 349 flags()->poison_in_malloc = do_poison; 350 return old; 351} 352 353int __msan_has_dynamic_component() { 354 return msan_running_under_dr; 355} 356 357NOINLINE 358void __msan_clear_on_return() { 359 __msan_param_tls[0] = 0; 360} 361 362static void* get_tls_base() { 363 u64 p; 364 asm("mov %%fs:0, %0" 365 : "=r"(p) ::); 366 return (void*)p; 367} 368 369int __msan_get_retval_tls_offset() { 370 // volatile here is needed to avoid UB, because the compiler thinks that we 371 // are doing address arithmetics on unrelated pointers, and takes some 372 // shortcuts 373 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 374 volatile sptr tls_base_p = (sptr)get_tls_base(); 375 return retval_tls_p - tls_base_p; 376} 377 378int __msan_get_param_tls_offset() { 379 // volatile here is needed to avoid UB, because the compiler thinks that we 380 // are doing address arithmetics on unrelated pointers, and takes some 381 // shortcuts 382 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 383 volatile sptr tls_base_p = (sptr)get_tls_base(); 384 return param_tls_p - tls_base_p; 385} 386 387void __msan_partial_poison(const void* data, void* shadow, uptr size) { 388 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 389} 390 391void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 392 internal_memcpy(dst, src, size); 393 __msan_unpoison(dst, size); 394} 395 396void __msan_set_origin(const void *a, uptr size, u32 origin) { 397 // Origin mapping is 4 bytes per 4 bytes of application memory. 398 // Here we extend the range such that its left and right bounds are both 399 // 4 byte aligned. 400 if (!__msan_get_track_origins()) return; 401 uptr x = MEM_TO_ORIGIN((uptr)a); 402 uptr beg = x & ~3UL; // align down. 403 uptr end = (x + size + 3) & ~3UL; // align up. 404 u64 origin64 = ((u64)origin << 32) | origin; 405 // This is like memset, but the value is 32-bit. We unroll by 2 two write 406 // 64-bits at once. May want to unroll further to get 128-bit stores. 407 if (beg & 7ULL) { 408 *(u32*)beg = origin; 409 beg += 4; 410 } 411 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 412 *(u64*)addr = origin64; 413 if (end & 7ULL) 414 *(u32*)(end - 4) = origin; 415} 416 417// 'descr' is created at compile time and contains '----' in the beginning. 418// When we see descr for the first time we replace '----' with a uniq id 419// and set the origin to (id | (31-th bit)). 420void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 421 static const u32 dash = '-'; 422 static const u32 first_timer = 423 dash + (dash << 8) + (dash << 16) + (dash << 24); 424 u32 *id_ptr = (u32*)descr; 425 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 426 u32 id = *id_ptr; 427 if (id == first_timer) { 428 id = atomic_fetch_add(&NumStackOriginDescrs, 429 1, memory_order_relaxed); 430 *id_ptr = id; 431 CHECK_LT(id, kNumStackOriginDescrs); 432 StackOriginDescr[id] = descr + 4; 433 if (print) 434 Printf("First time: id=%d %s \n", id, descr + 4); 435 } 436 id |= 1U << 31; 437 if (print) 438 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 439 __msan_set_origin(a, size, id); 440} 441 442const char *__msan_get_origin_descr_if_stack(u32 id) { 443 if ((id >> 31) == 0) return 0; 444 id &= (1U << 31) - 1; 445 CHECK_LT(id, kNumStackOriginDescrs); 446 return StackOriginDescr[id]; 447} 448 449 450u32 __msan_get_origin(const void *a) { 451 if (!__msan_get_track_origins()) return 0; 452 uptr x = (uptr)a; 453 uptr aligned = x & ~3ULL; 454 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 455 return *(u32*)origin_ptr; 456} 457 458u32 __msan_get_umr_origin() { 459 return __msan_origin_tls; 460} 461 462#if !SANITIZER_SUPPORTS_WEAK_HOOKS 463extern "C" { 464SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE 465const char* __msan_default_options() { return ""; } 466} // extern "C" 467#endif 468 469