msan.cc revision 10fd3227546d17c7411241a45ebc143b2031c78d
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; 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} 131 132static void InitializeFlags(Flags *f, const char *options) { 133 internal_memset(f, 0, sizeof(*f)); 134 135 f->poison_heap_with_zeroes = false; 136 f->poison_stack_with_zeroes = false; 137 f->poison_in_malloc = true; 138 f->exit_code = 77; 139 f->num_callers = 20; 140 f->report_umrs = true; 141 f->verbosity = 0; 142 f->strip_path_prefix = ""; 143 144 // Override from user-specified string. 145 if (__msan_default_options) 146 ParseFlagsFromString(f, __msan_default_options()); 147 ParseFlagsFromString(f, options); 148} 149 150static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { 151 if (__msan_stack_bounds.stack_top == 0) { 152 // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> 153 // realloc -> GetStackTrace). 154 __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; 155 GetThreadStackTopAndBottom(/* at_initialization */false, 156 &__msan_stack_bounds.stack_top, 157 &__msan_stack_bounds.stack_bottom); 158 } 159 *stack_top = __msan_stack_bounds.stack_top; 160 *stack_bottom = __msan_stack_bounds.stack_bottom; 161} 162 163void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, 164 bool fast) { 165 if (!fast) { 166 // Block reports from our interceptors during _Unwind_Backtrace. 167 SymbolizerScope sym_scope; 168 return stack->SlowUnwindStack(pc, max_s); 169 } 170 171 uptr stack_top, stack_bottom; 172 GetCurrentStackBounds(&stack_top, &stack_bottom); 173 stack->size = 0; 174 stack->trace[0] = pc; 175 stack->max_size = max_s; 176 stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); 177} 178 179void PrintWarning(uptr pc, uptr bp) { 180 PrintWarningWithOrigin(pc, bp, __msan_origin_tls); 181} 182 183bool OriginIsValid(u32 origin) { 184 return origin != 0 && origin != (u32)-1; 185} 186 187void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { 188 if (msan_expect_umr) { 189 // Printf("Expected UMR\n"); 190 __msan_origin_tls = origin; 191 msan_expected_umr_found = 1; 192 return; 193 } 194 195 ++msan_report_count; 196 197 StackTrace stack; 198 GetStackTrace(&stack, kStackTraceMax, pc, bp, /*fast*/false); 199 200 u32 report_origin = 201 (__msan_track_origins && OriginIsValid(origin)) ? origin : 0; 202 ReportUMR(&stack, report_origin); 203 204 if (__msan_track_origins && !OriginIsValid(origin)) { 205 Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " 206 "please report to MemorySanitizer developers.\n", 207 origin); 208 } 209} 210 211} // namespace __msan 212 213// Interface. 214 215using namespace __msan; 216 217void __msan_warning() { 218 GET_CALLER_PC_BP_SP; 219 (void)sp; 220 PrintWarning(pc, bp); 221} 222 223void __msan_warning_noreturn() { 224 GET_CALLER_PC_BP_SP; 225 (void)sp; 226 PrintWarning(pc, bp); 227 Printf("Exiting\n"); 228 Die(); 229} 230 231void __msan_init() { 232 if (msan_inited) return; 233 msan_init_is_running = 1; 234 SanitizerToolName = "MemorySanitizer"; 235 236 InstallAtExitHandler(); 237 SetDieCallback(MsanDie); 238 InitTlsSize(); 239 InitializeInterceptors(); 240 241 ReplaceOperatorsNewAndDelete(); 242 const char *msan_options = GetEnv("MSAN_OPTIONS"); 243 InitializeFlags(&msan_flags, msan_options); 244 if (StackSizeIsUnlimited()) { 245 if (flags()->verbosity) 246 Printf("Unlimited stack, doing reexec\n"); 247 // A reasonably large stack size. It is bigger than the usual 8Mb, because, 248 // well, the program could have been run with unlimited stack for a reason. 249 SetStackSizeLimitInBytes(32 * 1024 * 1024); 250 ReExec(); 251 } 252 253 if (flags()->verbosity) 254 Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); 255 256 msan_running_under_dr = IsRunningUnderDr(); 257 __msan_clear_on_return(); 258 if (__msan_track_origins && flags()->verbosity > 0) 259 Printf("msan_track_origins\n"); 260 if (!InitShadow(/* prot1 */false, /* prot2 */true, /* map_shadow */true, 261 __msan_track_origins)) { 262 // FIXME: prot1 = false is only required when running under DR. 263 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); 264 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); 265 Printf("FATAL: Disabling ASLR is known to cause this error.\n"); 266 Printf("FATAL: If running under GDB, try " 267 "'set disable-randomization off'.\n"); 268 DumpProcessMap(); 269 Die(); 270 } 271 272 const char *external_symbolizer = GetEnv("MSAN_SYMBOLIZER_PATH"); 273 if (external_symbolizer && external_symbolizer[0]) { 274 CHECK(InitializeExternalSymbolizer(external_symbolizer)); 275 } 276 277 GetThreadStackTopAndBottom(/* at_initialization */true, 278 &__msan_stack_bounds.stack_top, 279 &__msan_stack_bounds.stack_bottom); 280 if (flags()->verbosity) 281 Printf("MemorySanitizer init done\n"); 282 msan_init_is_running = 0; 283 msan_inited = 1; 284} 285 286void __msan_set_exit_code(int exit_code) { 287 flags()->exit_code = exit_code; 288} 289 290void __msan_set_expect_umr(int expect_umr) { 291 if (expect_umr) { 292 msan_expected_umr_found = 0; 293 } else if (!msan_expected_umr_found) { 294 GET_CALLER_PC_BP_SP; 295 (void)sp; 296 StackTrace stack; 297 GetStackTrace(&stack, kStackTraceMax, pc, bp, /*fast*/false); 298 ReportExpectedUMRNotFound(&stack); 299 Die(); 300 } 301 msan_expect_umr = expect_umr; 302} 303 304void __msan_print_shadow(const void *x, uptr size) { 305 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); 306 u32 *o = (u32*)MEM_TO_ORIGIN(x); 307 for (uptr i = 0; i < size; i++) { 308 Printf("%x%x ", s[i] >> 4, s[i] & 0xf); 309 } 310 Printf("\n"); 311 if (__msan_track_origins) { 312 for (uptr i = 0; i < size / 4; i++) { 313 Printf(" o: %x ", o[i]); 314 } 315 Printf("\n"); 316 } 317} 318 319void __msan_print_param_shadow() { 320 for (int i = 0; i < 16; i++) { 321 Printf("#%d:%zx ", i, __msan_param_tls[i]); 322 } 323 Printf("\n"); 324} 325 326sptr __msan_test_shadow(const void *x, uptr size) { 327 unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); 328 for (uptr i = 0; i < size; ++i) 329 if (s[i]) 330 return i; 331 return -1; 332} 333 334int __msan_set_poison_in_malloc(int do_poison) { 335 int old = flags()->poison_in_malloc; 336 flags()->poison_in_malloc = do_poison; 337 return old; 338} 339 340int __msan_has_dynamic_component() { 341 return msan_running_under_dr; 342} 343 344NOINLINE 345void __msan_clear_on_return() { 346 __msan_param_tls[0] = 0; 347} 348 349static void* get_tls_base() { 350 u64 p; 351 asm("mov %%fs:0, %0" 352 : "=r"(p) ::); 353 return (void*)p; 354} 355 356int __msan_get_retval_tls_offset() { 357 // volatile here is needed to avoid UB, because the compiler thinks that we 358 // are doing address arithmetics on unrelated pointers, and takes some 359 // shortcuts 360 volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; 361 volatile sptr tls_base_p = (sptr)get_tls_base(); 362 return retval_tls_p - tls_base_p; 363} 364 365int __msan_get_param_tls_offset() { 366 // volatile here is needed to avoid UB, because the compiler thinks that we 367 // are doing address arithmetics on unrelated pointers, and takes some 368 // shortcuts 369 volatile sptr param_tls_p = (sptr)&__msan_param_tls; 370 volatile sptr tls_base_p = (sptr)get_tls_base(); 371 return param_tls_p - tls_base_p; 372} 373 374void __msan_partial_poison(void* data, void* shadow, uptr size) { 375 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); 376} 377 378void __msan_load_unpoisoned(void *src, uptr size, void *dst) { 379 internal_memcpy(dst, src, size); 380 __msan_unpoison(dst, size); 381} 382 383void __msan_set_origin(void *a, uptr size, u32 origin) { 384 // Origin mapping is 4 bytes per 4 bytes of application memory. 385 // Here we extend the range such that its left and right bounds are both 386 // 4 byte aligned. 387 if (!__msan_track_origins) return; 388 uptr x = MEM_TO_ORIGIN((uptr)a); 389 uptr beg = x & ~3UL; // align down. 390 uptr end = (x + size + 3) & ~3UL; // align up. 391 u64 origin64 = ((u64)origin << 32) | origin; 392 // This is like memset, but the value is 32-bit. We unroll by 2 two write 393 // 64-bits at once. May want to unroll further to get 128-bit stores. 394 if (beg & 7ULL) { 395 *(u32*)beg = origin; 396 beg += 4; 397 } 398 for (uptr addr = beg; addr < (end & ~7UL); addr += 8) 399 *(u64*)addr = origin64; 400 if (end & 7ULL) 401 *(u32*)(end - 4) = origin; 402} 403 404// 'descr' is created at compile time and contains '----' in the beginning. 405// When we see descr for the first time we replace '----' with a uniq id 406// and set the origin to (id | (31-th bit)). 407void __msan_set_alloca_origin(void *a, uptr size, const char *descr) { 408 static const u32 dash = '-'; 409 static const u32 first_timer = 410 dash + (dash << 8) + (dash << 16) + (dash << 24); 411 u32 *id_ptr = (u32*)descr; 412 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; 413 u32 id = *id_ptr; 414 if (id == first_timer) { 415 id = atomic_fetch_add(&NumStackOriginDescrs, 416 1, memory_order_relaxed); 417 *id_ptr = id; 418 CHECK_LT(id, kNumStackOriginDescrs); 419 StackOriginDescr[id] = descr + 4; 420 if (print) 421 Printf("First time: id=%d %s \n", id, descr + 4); 422 } 423 id |= 1U << 31; 424 if (print) 425 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); 426 __msan_set_origin(a, size, id); 427} 428 429const char *__msan_get_origin_descr_if_stack(u32 id) { 430 if ((id >> 31) == 0) return 0; 431 id &= (1U << 31) - 1; 432 CHECK_LT(id, kNumStackOriginDescrs); 433 return StackOriginDescr[id]; 434} 435 436 437u32 __msan_get_origin(void *a) { 438 if (!__msan_track_origins) return 0; 439 uptr x = (uptr)a; 440 uptr aligned = x & ~3ULL; 441 uptr origin_ptr = MEM_TO_ORIGIN(aligned); 442 return *(u32*)origin_ptr; 443} 444 445u32 __msan_get_umr_origin() { 446 return __msan_origin_tls; 447} 448 449#if !SANITIZER_SUPPORTS_WEAK_HOOKS 450extern "C" { 451SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE 452const char* __msan_default_options() { return ""; } 453} // extern "C" 454#endif 455 456