msan.cc revision 2bba4efbf0df4bfac8e0aac1a924ba763dd9c468
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" const int __msan_track_origins; 65int __msan_get_track_origins() { 66 return __msan_track_origins; 67} 68 69namespace __msan { 70 71static bool IsRunningUnderDr() { 72 bool result = false; 73 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 74 const sptr kBufSize = 4095; 75 char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__); 76 while (proc_maps.Next(/* start */0, /* end */0, /* file_offset */0, 77 filename, kBufSize, /* protection */0)) { 78 if (internal_strstr(filename, "libdynamorio") != 0) { 79 result = true; 80 break; 81 } 82 } 83 UnmapOrDie(filename, kBufSize); 84 return result; 85} 86 87void EnterSymbolizer() { is_in_symbolizer = true; } 88void ExitSymbolizer() { is_in_symbolizer = false; } 89bool IsInSymbolizer() { return is_in_symbolizer; } 90 91void EnterLoader() { is_in_loader = true; } 92void ExitLoader() { is_in_loader = false; } 93 94extern "C" { 95SANITIZER_INTERFACE_ATTRIBUTE 96bool __msan_is_in_loader() { return is_in_loader; } 97} 98 99static Flags msan_flags; 100 101Flags *flags() { 102 return &msan_flags; 103} 104 105int msan_inited = 0; 106bool msan_init_is_running; 107 108int msan_report_count = 0; 109 110// Array of stack origins. 111// FIXME: make it resizable. 112static const uptr kNumStackOriginDescrs = 1024 * 1024; 113static const char *StackOriginDescr[kNumStackOriginDescrs]; 114static atomic_uint32_t NumStackOriginDescrs; 115 116static void ParseFlagsFromString(Flags *f, const char *str) { 117 ParseCommonFlagsFromString(str); 118 ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); 119 ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); 120 ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); 121 ParseFlag(str, &f->exit_code, "exit_code"); 122 if (f->exit_code < 0 || f->exit_code > 127) { 123 Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); 124 f->exit_code = 1; 125 Die(); 126 } 127 ParseFlag(str, &f->report_umrs, "report_umrs"); 128 ParseFlag(str, &f->verbosity, "verbosity"); 129 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 130} 131 132static void InitializeFlags(Flags *f, const char *options) { 133 CommonFlags *cf = common_flags(); 134 cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); 135 cf->strip_path_prefix = ""; 136 cf->fast_unwind_on_fatal = false; 137 cf->fast_unwind_on_malloc = true; 138 cf->malloc_context_size = 20; 139 140 internal_memset(f, 0, sizeof(*f)); 141 f->poison_heap_with_zeroes = false; 142 f->poison_stack_with_zeroes = false; 143 f->poison_in_malloc = true; 144 f->exit_code = 77; 145 f->report_umrs = true; 146 f->verbosity = 0; 147 f->wrap_signals = true; 148 149 // Override from user-specified string. 150 if (__msan_default_options) 151 ParseFlagsFromString(f, __msan_default_options()); 152 ParseFlagsFromString(f, options); 153} 154 155static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 156 if (__msan_stack_bounds.stack_top == 0) { 157 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 158 // realloc -> GetStackTrace). 159 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 160 GetThreadStackTopAndBottom(/* at_initialization */false, 161 &__msan_stack_bounds.stack_top, 162 &__msan_stack_bounds.stack_bottom); 163 } 164 *stack_top = __msan_stack_bounds.stack_top; 165 *stack_bottom = __msan_stack_bounds.stack_bottom; 166} 167 168void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 169 bool fast) { 170 if (!fast) { 171 // Block reports from our interceptors during _Unwind_Backtrace. 172 SymbolizerScope sym_scope; 173 return stack->SlowUnwindStack(pc, max_s); 174 } 175 176 uptr stack_top, stack_bottom; 177 GetCurrentStackBounds(&stack_top, &stack_bottom); 178 stack->size = 0; 179 stack->trace[0] = pc; 180 stack->max_size = max_s; 181 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); 182} 183 184void PrintWarning(uptr pc, uptr bp) { 185 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 186} 187 188bool OriginIsValid(u32 origin) { 189 return origin != 0 && origin != (u32)-1; 190} 191 192void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 193 if (msan_expect_umr) { 194 // Printf("Expected UMR\n"); 195 __msan_origin_tls = origin; 196 msan_expected_umr_found = 1; 197 return; 198 } 199 200 ++msan_report_count; 201 202 StackTrace stack; 203 GetStackTrace(&stack, kStackTraceMax, pc, bp, 204 common_flags()->fast_unwind_on_fatal); 205 206 u32 report_origin = 207 (__msan_track_origins && OriginIsValid(origin)) ? origin : 0; 208 ReportUMR(&stack, report_origin); 209 210 if (__msan_track_origins && !OriginIsValid(origin)) { 211 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 212 "please report to MemorySanitizer developers.\n", 213 origin); 214 } 215} 216 217} // namespace __msan 218 219// Interface. 220 221using namespace __msan; 222 223void __msan_warning() { 224 GET_CALLER_PC_BP_SP; 225 (void)sp; 226 PrintWarning(pc, bp); 227} 228 229void __msan_warning_noreturn() { 230 GET_CALLER_PC_BP_SP; 231 (void)sp; 232 PrintWarning(pc, bp); 233 Printf("Exiting\n"); 234 Die(); 235} 236 237void __msan_init() { 238 if (msan_inited) return; 239 msan_init_is_running = 1; 240 SanitizerToolName = "MemorySanitizer"; 241 242 InstallAtExitHandler(); 243 SetDieCallback(MsanDie); 244 InitTlsSize(); 245 InitializeInterceptors(); 246 247 if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) 248 ReplaceOperatorsNewAndDelete(); 249 const char *msan_options = GetEnv("MSAN_OPTIONS"); 250 InitializeFlags(&msan_flags, msan_options); 251 if (StackSizeIsUnlimited()) { 252 if (flags()->verbosity) 253 Printf("Unlimited stack, doing reexec\n"); 254 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 255 // well, the program could have been run with unlimited stack for a reason. 256 SetStackSizeLimitInBytes(32 * 1024 * 1024); 257 ReExec(); 258 } 259 260 if (flags()->verbosity) 261 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 262 263 msan_running_under_dr = IsRunningUnderDr(); 264 __msan_clear_on_return(); 265 if (__msan_track_origins && flags()->verbosity > 0) 266 Printf("msan_track_origins\n"); 267 if (!InitShadow(/* prot1 */false, /* prot2 */true, /* map_shadow */true, 268 __msan_track_origins)) { 269 // FIXME: prot1 = false is only required when running under DR. 270 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 271 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 272 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 273 Printf("FATAL: If running under GDB, try " 274 "'set disable-randomization off'.\n"); 275 DumpProcessMap(); 276 Die(); 277 } 278 279 const char *external_symbolizer = common_flags()->external_symbolizer_path; 280 if (external_symbolizer && external_symbolizer[0]) { 281 CHECK(InitializeExternalSymbolizer(external_symbolizer)); 282 } 283 284 GetThreadStackTopAndBottom(/* at_initialization */true, 285 &__msan_stack_bounds.stack_top, 286 &__msan_stack_bounds.stack_bottom); 287 if (flags()->verbosity) 288 Printf("MemorySanitizer init done\n"); 289 msan_init_is_running = 0; 290 msan_inited = 1; 291} 292 293void __msan_set_exit_code(int exit_code) { 294 flags()->exit_code = exit_code; 295} 296 297void __msan_set_expect_umr(int expect_umr) { 298 if (expect_umr) { 299 msan_expected_umr_found = 0; 300 } else if (!msan_expected_umr_found) { 301 GET_CALLER_PC_BP_SP; 302 (void)sp; 303 StackTrace stack; 304 GetStackTrace(&stack, kStackTraceMax, pc, bp, 305 common_flags()->fast_unwind_on_fatal); 306 ReportExpectedUMRNotFound(&stack); 307 Die(); 308 } 309 msan_expect_umr = expect_umr; 310} 311 312void __msan_print_shadow(const void *x, uptr size) { 313 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 314 u32 *o = (u32*)MEM_TO_ORIGIN(x); 315 for (uptr i = 0; i < size; i++) { 316 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 317 } 318 Printf("\n"); 319 if (__msan_track_origins) { 320 for (uptr i = 0; i < size / 4; i++) { 321 Printf(" o: %x ", o[i]); 322 } 323 Printf("\n"); 324 } 325} 326 327void __msan_print_param_shadow() { 328 for (int i = 0; i < 16; i++) { 329 Printf("#%d:%zx ", i, __msan_param_tls[i]); 330 } 331 Printf("\n"); 332} 333 334void __msan_unpoison_param(uptr n) { 335 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); 336} 337 338sptr __msan_test_shadow(const void *x, uptr size) { 339 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 340 for (uptr i = 0; i < size; ++i) 341 if (s[i]) 342 return i; 343 return -1; 344} 345 346int __msan_set_poison_in_malloc(int do_poison) { 347 int old = flags()->poison_in_malloc; 348 flags()->poison_in_malloc = do_poison; 349 return old; 350} 351 352int __msan_has_dynamic_component() { 353 return msan_running_under_dr; 354} 355 356NOINLINE 357void __msan_clear_on_return() { 358 __msan_param_tls[0] = 0; 359} 360 361static void* get_tls_base() { 362 u64 p; 363 asm("mov %%fs:0, %0" 364 : "=r"(p) ::); 365 return (void*)p; 366} 367 368int __msan_get_retval_tls_offset() { 369 // volatile here is needed to avoid UB, because the compiler thinks that we 370 // are doing address arithmetics on unrelated pointers, and takes some 371 // shortcuts 372 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 373 volatile sptr tls_base_p = (sptr)get_tls_base(); 374 return retval_tls_p - tls_base_p; 375} 376 377int __msan_get_param_tls_offset() { 378 // volatile here is needed to avoid UB, because the compiler thinks that we 379 // are doing address arithmetics on unrelated pointers, and takes some 380 // shortcuts 381 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 382 volatile sptr tls_base_p = (sptr)get_tls_base(); 383 return param_tls_p - tls_base_p; 384} 385 386void __msan_partial_poison(const void* data, void* shadow, uptr size) { 387 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 388} 389 390void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 391 internal_memcpy(dst, src, size); 392 __msan_unpoison(dst, size); 393} 394 395void __msan_set_origin(const void *a, uptr size, u32 origin) { 396 // Origin mapping is 4 bytes per 4 bytes of application memory. 397 // Here we extend the range such that its left and right bounds are both 398 // 4 byte aligned. 399 if (!__msan_track_origins) return; 400 uptr x = MEM_TO_ORIGIN((uptr)a); 401 uptr beg = x & ~3UL; // align down. 402 uptr end = (x + size + 3) & ~3UL; // align up. 403 u64 origin64 = ((u64)origin << 32) | origin; 404 // This is like memset, but the value is 32-bit. We unroll by 2 two write 405 // 64-bits at once. May want to unroll further to get 128-bit stores. 406 if (beg & 7ULL) { 407 *(u32*)beg = origin; 408 beg += 4; 409 } 410 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 411 *(u64*)addr = origin64; 412 if (end & 7ULL) 413 *(u32*)(end - 4) = origin; 414} 415 416// 'descr' is created at compile time and contains '----' in the beginning. 417// When we see descr for the first time we replace '----' with a uniq id 418// and set the origin to (id | (31-th bit)). 419void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 420 static const u32 dash = '-'; 421 static const u32 first_timer = 422 dash + (dash << 8) + (dash << 16) + (dash << 24); 423 u32 *id_ptr = (u32*)descr; 424 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 425 u32 id = *id_ptr; 426 if (id == first_timer) { 427 id = atomic_fetch_add(&NumStackOriginDescrs, 428 1, memory_order_relaxed); 429 *id_ptr = id; 430 CHECK_LT(id, kNumStackOriginDescrs); 431 StackOriginDescr[id] = descr + 4; 432 if (print) 433 Printf("First time: id=%d %s \n", id, descr + 4); 434 } 435 id |= 1U << 31; 436 if (print) 437 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 438 __msan_set_origin(a, size, id); 439} 440 441const char *__msan_get_origin_descr_if_stack(u32 id) { 442 if ((id >> 31) == 0) return 0; 443 id &= (1U << 31) - 1; 444 CHECK_LT(id, kNumStackOriginDescrs); 445 return StackOriginDescr[id]; 446} 447 448 449u32 __msan_get_origin(const void *a) { 450 if (!__msan_track_origins) return 0; 451 uptr x = (uptr)a; 452 uptr aligned = x & ~3ULL; 453 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 454 return *(u32*)origin_ptr; 455} 456 457u32 __msan_get_umr_origin() { 458 return __msan_origin_tls; 459} 460 461#if !SANITIZER_SUPPORTS_WEAK_HOOKS 462extern "C" { 463SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE 464const char* __msan_default_options() { return ""; } 465} // extern "C" 466#endif 467 468