msan.cc revision a213ab66e1c743ec7a52af4a49ec6c126cc245ae
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 ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); 118 ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); 119 ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); 120 ParseFlag(str, &f->exit_code, "exit_code"); 121 if (f->exit_code < 0 || f->exit_code > 127) { 122 Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); 123 f->exit_code = 1; 124 Die(); 125 } 126 ParseFlag(str, &f->num_callers, "num_callers"); 127 ParseFlag(str, &f->report_umrs, "report_umrs"); 128 ParseFlag(str, &f->verbosity, "verbosity"); 129 ParseFlag(str, &f->strip_path_prefix, "strip_path_prefix"); 130 ParseFlag(str, &f->fast_unwind_on_fatal, "fast_unwind_on_fatal"); 131 ParseFlag(str, &f->fast_unwind_on_malloc, "fast_unwind_on_malloc"); 132 ParseFlag(str, &f->wrap_signals, "wrap_signals"); 133} 134 135static void InitializeFlags(Flags *f, const char *options) { 136 internal_memset(f, 0, sizeof(*f)); 137 138 f->poison_heap_with_zeroes = false; 139 f->poison_stack_with_zeroes = false; 140 f->poison_in_malloc = true; 141 f->exit_code = 77; 142 f->num_callers = 20; 143 f->report_umrs = true; 144 f->verbosity = 0; 145 f->strip_path_prefix = ""; 146 f->fast_unwind_on_fatal = false; 147 f->fast_unwind_on_malloc = true; 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, 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 ReplaceOperatorsNewAndDelete(); 248 const char *msan_options = GetEnv("MSAN_OPTIONS"); 249 InitializeFlags(&msan_flags, msan_options); 250 if (StackSizeIsUnlimited()) { 251 if (flags()->verbosity) 252 Printf("Unlimited stack, doing reexec\n"); 253 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 254 // well, the program could have been run with unlimited stack for a reason. 255 SetStackSizeLimitInBytes(32 * 1024 * 1024); 256 ReExec(); 257 } 258 259 if (flags()->verbosity) 260 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 261 262 msan_running_under_dr = IsRunningUnderDr(); 263 __msan_clear_on_return(); 264 if (__msan_track_origins && flags()->verbosity > 0) 265 Printf("msan_track_origins\n"); 266 if (!InitShadow(/* prot1 */false, /* prot2 */true, /* map_shadow */true, 267 __msan_track_origins)) { 268 // FIXME: prot1 = false is only required when running under DR. 269 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 270 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 271 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 272 Printf("FATAL: If running under GDB, try " 273 "'set disable-randomization off'.\n"); 274 DumpProcessMap(); 275 Die(); 276 } 277 278 const char *external_symbolizer = GetEnv("MSAN_SYMBOLIZER_PATH"); 279 if (external_symbolizer && external_symbolizer[0]) { 280 CHECK(InitializeExternalSymbolizer(external_symbolizer)); 281 } 282 283 GetThreadStackTopAndBottom(/* at_initialization */true, 284 &__msan_stack_bounds.stack_top, 285 &__msan_stack_bounds.stack_bottom); 286 if (flags()->verbosity) 287 Printf("MemorySanitizer init done\n"); 288 msan_init_is_running = 0; 289 msan_inited = 1; 290} 291 292void __msan_set_exit_code(int exit_code) { 293 flags()->exit_code = exit_code; 294} 295 296void __msan_set_expect_umr(int expect_umr) { 297 if (expect_umr) { 298 msan_expected_umr_found = 0; 299 } else if (!msan_expected_umr_found) { 300 GET_CALLER_PC_BP_SP; 301 (void)sp; 302 StackTrace stack; 303 GetStackTrace(&stack, kStackTraceMax, pc, bp, 304 flags()->fast_unwind_on_fatal); 305 ReportExpectedUMRNotFound(&stack); 306 Die(); 307 } 308 msan_expect_umr = expect_umr; 309} 310 311void __msan_print_shadow(const void *x, uptr size) { 312 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 313 u32 *o = (u32*)MEM_TO_ORIGIN(x); 314 for (uptr i = 0; i < size; i++) { 315 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 316 } 317 Printf("\n"); 318 if (__msan_track_origins) { 319 for (uptr i = 0; i < size / 4; i++) { 320 Printf(" o: %x ", o[i]); 321 } 322 Printf("\n"); 323 } 324} 325 326void __msan_print_param_shadow() { 327 for (int i = 0; i < 16; i++) { 328 Printf("#%d:%zx ", i, __msan_param_tls[i]); 329 } 330 Printf("\n"); 331} 332 333sptr __msan_test_shadow(const void *x, uptr size) { 334 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 335 for (uptr i = 0; i < size; ++i) 336 if (s[i]) 337 return i; 338 return -1; 339} 340 341int __msan_set_poison_in_malloc(int do_poison) { 342 int old = flags()->poison_in_malloc; 343 flags()->poison_in_malloc = do_poison; 344 return old; 345} 346 347int __msan_has_dynamic_component() { 348 return msan_running_under_dr; 349} 350 351NOINLINE 352void __msan_clear_on_return() { 353 __msan_param_tls[0] = 0; 354} 355 356static void* get_tls_base() { 357 u64 p; 358 asm("mov %%fs:0, %0" 359 : "=r"(p) ::); 360 return (void*)p; 361} 362 363int __msan_get_retval_tls_offset() { 364 // volatile here is needed to avoid UB, because the compiler thinks that we 365 // are doing address arithmetics on unrelated pointers, and takes some 366 // shortcuts 367 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 368 volatile sptr tls_base_p = (sptr)get_tls_base(); 369 return retval_tls_p - tls_base_p; 370} 371 372int __msan_get_param_tls_offset() { 373 // volatile here is needed to avoid UB, because the compiler thinks that we 374 // are doing address arithmetics on unrelated pointers, and takes some 375 // shortcuts 376 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 377 volatile sptr tls_base_p = (sptr)get_tls_base(); 378 return param_tls_p - tls_base_p; 379} 380 381void __msan_partial_poison(void* data, void* shadow, uptr size) { 382 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 383} 384 385void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 386 internal_memcpy(dst, src, size); 387 __msan_unpoison(dst, size); 388} 389 390void __msan_set_origin(void *a, uptr size, u32 origin) { 391 // Origin mapping is 4 bytes per 4 bytes of application memory. 392 // Here we extend the range such that its left and right bounds are both 393 // 4 byte aligned. 394 if (!__msan_track_origins) return; 395 uptr x = MEM_TO_ORIGIN((uptr)a); 396 uptr beg = x & ~3UL; // align down. 397 uptr end = (x + size + 3) & ~3UL; // align up. 398 u64 origin64 = ((u64)origin << 32) | origin; 399 // This is like memset, but the value is 32-bit. We unroll by 2 two write 400 // 64-bits at once. May want to unroll further to get 128-bit stores. 401 if (beg & 7ULL) { 402 *(u32*)beg = origin; 403 beg += 4; 404 } 405 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 406 *(u64*)addr = origin64; 407 if (end & 7ULL) 408 *(u32*)(end - 4) = origin; 409} 410 411// 'descr' is created at compile time and contains '----' in the beginning. 412// When we see descr for the first time we replace '----' with a uniq id 413// and set the origin to (id | (31-th bit)). 414void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 415 static const u32 dash = '-'; 416 static const u32 first_timer = 417 dash + (dash << 8) + (dash << 16) + (dash << 24); 418 u32 *id_ptr = (u32*)descr; 419 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 420 u32 id = *id_ptr; 421 if (id == first_timer) { 422 id = atomic_fetch_add(&NumStackOriginDescrs, 423 1, memory_order_relaxed); 424 *id_ptr = id; 425 CHECK_LT(id, kNumStackOriginDescrs); 426 StackOriginDescr[id] = descr + 4; 427 if (print) 428 Printf("First time: id=%d %s \n", id, descr + 4); 429 } 430 id |= 1U << 31; 431 if (print) 432 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 433 __msan_set_origin(a, size, id); 434} 435 436const char *__msan_get_origin_descr_if_stack(u32 id) { 437 if ((id >> 31) == 0) return 0; 438 id &= (1U << 31) - 1; 439 CHECK_LT(id, kNumStackOriginDescrs); 440 return StackOriginDescr[id]; 441} 442 443 444u32 __msan_get_origin(void *a) { 445 if (!__msan_track_origins) return 0; 446 uptr x = (uptr)a; 447 uptr aligned = x & ~3ULL; 448 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 449 return *(u32*)origin_ptr; 450} 451 452u32 __msan_get_umr_origin() { 453 return __msan_origin_tls; 454} 455 456#if !SANITIZER_SUPPORTS_WEAK_HOOKS 457extern "C" { 458SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE 459const char* __msan_default_options() { return ""; } 460} // extern "C" 461#endif 462 463