1 //===-- msan.cc -----------------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of MemorySanitizer.
12 // MemorySanitizer runtime.
13 //===----------------------------------------------------------------------===//
16 #include "msan_chained_origin_depot.h"
17 #include "msan_origin.h"
18 #include "msan_thread.h"
19 #include "msan_poisoning.h"
20 #include "sanitizer_common/sanitizer_atomic.h"
21 #include "sanitizer_common/sanitizer_common.h"
22 #include "sanitizer_common/sanitizer_flags.h"
23 #include "sanitizer_common/sanitizer_flag_parser.h"
24 #include "sanitizer_common/sanitizer_libc.h"
25 #include "sanitizer_common/sanitizer_procmaps.h"
26 #include "sanitizer_common/sanitizer_stacktrace.h"
27 #include "sanitizer_common/sanitizer_symbolizer.h"
28 #include "sanitizer_common/sanitizer_stackdepot.h"
29 #include "ubsan/ubsan_flags.h"
30 #include "ubsan/ubsan_init.h"
32 // ACHTUNG! No system header includes in this file.
34 using namespace __sanitizer;
37 static THREADLOCAL int msan_expect_umr = 0;
38 static THREADLOCAL int msan_expected_umr_found = 0;
40 // Function argument shadow. Each argument starts at the next available 8-byte
42 SANITIZER_INTERFACE_ATTRIBUTE
43 THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSize / sizeof(u64)];
45 // Function argument origin. Each argument starts at the same offset as the
46 // corresponding shadow in (__msan_param_tls). Slightly weird, but changing this
47 // would break compatibility with older prebuilt binaries.
48 SANITIZER_INTERFACE_ATTRIBUTE
49 THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSize / sizeof(u32)];
51 SANITIZER_INTERFACE_ATTRIBUTE
52 THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSize / sizeof(u64)];
54 SANITIZER_INTERFACE_ATTRIBUTE
55 THREADLOCAL u32 __msan_retval_origin_tls;
57 SANITIZER_INTERFACE_ATTRIBUTE
58 ALIGNED(16) THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];
60 SANITIZER_INTERFACE_ATTRIBUTE
61 THREADLOCAL u64 __msan_va_arg_overflow_size_tls;
63 SANITIZER_INTERFACE_ATTRIBUTE
64 THREADLOCAL u32 __msan_origin_tls;
66 static THREADLOCAL int is_in_symbolizer;
68 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins;
70 int __msan_get_track_origins() {
71 return &__msan_track_origins ? __msan_track_origins : 0;
74 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going;
78 void EnterSymbolizer() { ++is_in_symbolizer; }
79 void ExitSymbolizer() { --is_in_symbolizer; }
80 bool IsInSymbolizer() { return is_in_symbolizer; }
82 static Flags msan_flags;
89 bool msan_init_is_running;
91 int msan_report_count = 0;
93 // Array of stack origins.
94 // FIXME: make it resizable.
95 static const uptr kNumStackOriginDescrs = 1024 * 1024;
96 static const char *StackOriginDescr[kNumStackOriginDescrs];
97 static uptr StackOriginPC[kNumStackOriginDescrs];
98 static atomic_uint32_t NumStackOriginDescrs;
100 void Flags::SetDefaults() {
101 #define MSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
102 #include "msan_flags.inc"
106 // keep_going is an old name for halt_on_error,
107 // and it has inverse meaning.
108 class FlagHandlerKeepGoing : public FlagHandlerBase {
109 bool *halt_on_error_;
112 explicit FlagHandlerKeepGoing(bool *halt_on_error)
113 : halt_on_error_(halt_on_error) {}
114 bool Parse(const char *value) final {
116 FlagHandler<bool> h(&tmp);
117 if (!h.Parse(value)) return false;
118 *halt_on_error_ = !tmp;
123 static void RegisterMsanFlags(FlagParser *parser, Flags *f) {
124 #define MSAN_FLAG(Type, Name, DefaultValue, Description) \
125 RegisterFlag(parser, #Name, Description, &f->Name);
126 #include "msan_flags.inc"
129 FlagHandlerKeepGoing *fh_keep_going = new (FlagParser::Alloc) // NOLINT
130 FlagHandlerKeepGoing(&f->halt_on_error);
131 parser->RegisterHandler("keep_going", fh_keep_going,
132 "deprecated, use halt_on_error");
135 static void InitializeFlags() {
136 SetCommonFlagsDefaults();
139 cf.CopyFrom(*common_flags());
140 cf.external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH");
141 cf.malloc_context_size = 20;
142 cf.handle_ioctl = true;
143 // FIXME: test and enable.
144 cf.check_printf = false;
145 cf.intercept_tls_get_addr = true;
147 OverrideCommonFlags(cf);
154 RegisterMsanFlags(&parser, f);
155 RegisterCommonFlags(&parser);
157 #if MSAN_CONTAINS_UBSAN
158 __ubsan::Flags *uf = __ubsan::flags();
161 FlagParser ubsan_parser;
162 __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
163 RegisterCommonFlags(&ubsan_parser);
166 // Override from user-specified string.
167 if (__msan_default_options)
168 parser.ParseString(__msan_default_options());
169 #if MSAN_CONTAINS_UBSAN
170 const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
171 ubsan_parser.ParseString(ubsan_default_options);
174 const char *msan_options = GetEnv("MSAN_OPTIONS");
175 parser.ParseString(msan_options);
176 #if MSAN_CONTAINS_UBSAN
177 ubsan_parser.ParseString(GetEnv("UBSAN_OPTIONS"));
179 VPrintf(1, "MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>");
181 InitializeCommonFlags();
183 if (Verbosity()) ReportUnrecognizedFlags();
185 if (common_flags()->help) parser.PrintFlagDescriptions();
187 // Check if deprecated exit_code MSan flag is set.
188 if (f->exit_code != -1) {
190 Printf("MSAN_OPTIONS=exit_code is deprecated! "
191 "Please use MSAN_OPTIONS=exitcode instead.\n");
193 cf.CopyFrom(*common_flags());
194 cf.exitcode = f->exit_code;
195 OverrideCommonFlags(cf);
198 // Check flag values:
199 if (f->origin_history_size < 0 ||
200 f->origin_history_size > Origin::kMaxDepth) {
202 "Origin history size invalid: %d. Must be 0 (unlimited) or in [1, %d] "
204 f->origin_history_size, Origin::kMaxDepth);
207 // Limiting to kStackDepotMaxUseCount / 2 to avoid overflow in
208 // StackDepotHandle::inc_use_count_unsafe.
209 if (f->origin_history_per_stack_limit < 0 ||
210 f->origin_history_per_stack_limit > kStackDepotMaxUseCount / 2) {
212 "Origin per-stack limit invalid: %d. Must be 0 (unlimited) or in [1, "
214 f->origin_history_per_stack_limit, kStackDepotMaxUseCount / 2);
217 if (f->store_context_size < 1) f->store_context_size = 1;
220 void GetStackTrace(BufferedStackTrace *stack, uptr max_s, uptr pc, uptr bp,
221 void *context, bool request_fast_unwind) {
222 MsanThread *t = GetCurrentThread();
223 if (!t || !StackTrace::WillUseFastUnwind(request_fast_unwind)) {
224 // Block reports from our interceptors during _Unwind_Backtrace.
225 SymbolizerScope sym_scope;
226 return stack->Unwind(max_s, pc, bp, context, 0, 0, request_fast_unwind);
228 stack->Unwind(max_s, pc, bp, context, t->stack_top(), t->stack_bottom(),
229 request_fast_unwind);
232 void PrintWarning(uptr pc, uptr bp) {
233 PrintWarningWithOrigin(pc, bp, __msan_origin_tls);
236 void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) {
237 if (msan_expect_umr) {
238 // Printf("Expected UMR\n");
239 __msan_origin_tls = origin;
240 msan_expected_umr_found = 1;
246 GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
249 (__msan_get_track_origins() && Origin::isValidId(origin)) ? origin : 0;
250 ReportUMR(&stack, report_origin);
252 if (__msan_get_track_origins() && !Origin::isValidId(origin)) {
254 " ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin "
255 "tracking.\n This could still be a bug in your code, too!\n",
260 void UnpoisonParam(uptr n) {
261 internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls));
264 // Backup MSan runtime TLS state.
265 // Implementation must be async-signal-safe.
266 // Instances of this class may live on the signal handler stack, and data size
268 void ScopedThreadLocalStateBackup::Backup() {
269 va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls;
272 void ScopedThreadLocalStateBackup::Restore() {
273 // A lame implementation that only keeps essential state and resets the rest.
274 __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls;
276 internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
277 internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
278 internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
280 if (__msan_get_track_origins()) {
281 internal_memset(&__msan_retval_origin_tls, 0,
282 sizeof(__msan_retval_origin_tls));
283 internal_memset(__msan_param_origin_tls, 0,
284 sizeof(__msan_param_origin_tls));
288 void UnpoisonThreadLocalState() {
291 const char *GetStackOriginDescr(u32 id, uptr *pc) {
292 CHECK_LT(id, kNumStackOriginDescrs);
293 if (pc) *pc = StackOriginPC[id];
294 return StackOriginDescr[id];
297 u32 ChainOrigin(u32 id, StackTrace *stack) {
298 MsanThread *t = GetCurrentThread();
299 if (t && t->InSignalHandler())
302 Origin o = Origin::FromRawId(id);
303 stack->tag = StackTrace::TAG_UNKNOWN;
304 Origin chained = Origin::CreateChainedOrigin(o, stack);
305 return chained.raw_id();
308 } // namespace __msan
312 using namespace __msan;
314 #define MSAN_MAYBE_WARNING(type, size) \
315 void __msan_maybe_warning_##size(type s, u32 o) { \
316 GET_CALLER_PC_BP_SP; \
319 PrintWarningWithOrigin(pc, bp, o); \
320 if (__msan::flags()->halt_on_error) { \
321 Printf("Exiting\n"); \
327 MSAN_MAYBE_WARNING(u8, 1)
328 MSAN_MAYBE_WARNING(u16, 2)
329 MSAN_MAYBE_WARNING(u32, 4)
330 MSAN_MAYBE_WARNING(u64, 8)
332 #define MSAN_MAYBE_STORE_ORIGIN(type, size) \
333 void __msan_maybe_store_origin_##size(type s, void *p, u32 o) { \
335 if (__msan_get_track_origins() > 1) { \
336 GET_CALLER_PC_BP_SP; \
338 GET_STORE_STACK_TRACE_PC_BP(pc, bp); \
339 o = ChainOrigin(o, &stack); \
341 *(u32 *)MEM_TO_ORIGIN((uptr)p & ~3UL) = o; \
345 MSAN_MAYBE_STORE_ORIGIN(u8, 1)
346 MSAN_MAYBE_STORE_ORIGIN(u16, 2)
347 MSAN_MAYBE_STORE_ORIGIN(u32, 4)
348 MSAN_MAYBE_STORE_ORIGIN(u64, 8)
350 void __msan_warning() {
353 PrintWarning(pc, bp);
354 if (__msan::flags()->halt_on_error) {
355 if (__msan::flags()->print_stats)
362 void __msan_warning_noreturn() {
365 PrintWarning(pc, bp);
366 if (__msan::flags()->print_stats)
372 static void OnStackUnwind(const SignalContext &sig, const void *,
373 BufferedStackTrace *stack) {
374 GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, sig.context,
375 common_flags()->fast_unwind_on_fatal);
378 static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) {
379 HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
383 CHECK(!msan_init_is_running);
384 if (msan_inited) return;
385 msan_init_is_running = 1;
386 SanitizerToolName = "MemorySanitizer";
388 AvoidCVE_2016_2143();
394 __sanitizer_set_report_path(common_flags()->log_path);
396 InitializeInterceptors();
397 InstallDeadlySignalHandlers(MsanOnDeadlySignal);
398 InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
400 DisableCoreDumperIfNecessary();
401 if (StackSizeIsUnlimited()) {
402 VPrintf(1, "Unlimited stack, doing reexec\n");
403 // A reasonably large stack size. It is bigger than the usual 8Mb, because,
404 // well, the program could have been run with unlimited stack for a reason.
405 SetStackSizeLimitInBytes(32 * 1024 * 1024);
409 __msan_clear_on_return();
410 if (__msan_get_track_origins())
411 VPrintf(1, "msan_track_origins\n");
412 if (!InitShadow(__msan_get_track_origins())) {
413 Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n");
414 Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
415 Printf("FATAL: Disabling ASLR is known to cause this error.\n");
416 Printf("FATAL: If running under GDB, try "
417 "'set disable-randomization off'.\n");
422 Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer);
424 InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
426 MsanTSDInit(MsanTSDDtor);
430 MsanThread *main_thread = MsanThread::Create(nullptr, nullptr);
431 SetCurrentThread(main_thread);
432 main_thread->ThreadStart();
434 #if MSAN_CONTAINS_UBSAN
435 __ubsan::InitAsPlugin();
438 VPrintf(1, "MemorySanitizer init done\n");
440 msan_init_is_running = 0;
444 void __msan_set_keep_going(int keep_going) {
445 flags()->halt_on_error = !keep_going;
448 void __msan_set_expect_umr(int expect_umr) {
450 msan_expected_umr_found = 0;
451 } else if (!msan_expected_umr_found) {
454 GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
455 ReportExpectedUMRNotFound(&stack);
458 msan_expect_umr = expect_umr;
461 void __msan_print_shadow(const void *x, uptr size) {
462 if (!MEM_IS_APP(x)) {
463 Printf("Not a valid application address: %p\n", x);
467 DescribeMemoryRange(x, size);
470 void __msan_dump_shadow(const void *x, uptr size) {
471 if (!MEM_IS_APP(x)) {
472 Printf("Not a valid application address: %p\n", x);
476 unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x);
477 for (uptr i = 0; i < size; i++)
478 Printf("%x%x ", s[i] >> 4, s[i] & 0xf);
482 sptr __msan_test_shadow(const void *x, uptr size) {
483 if (!MEM_IS_APP(x)) return -1;
484 unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x);
485 for (uptr i = 0; i < size; ++i)
491 void __msan_check_mem_is_initialized(const void *x, uptr size) {
492 if (!__msan::flags()->report_umrs) return;
493 sptr offset = __msan_test_shadow(x, size);
499 ReportUMRInsideAddressRange(__func__, x, size, offset);
500 __msan::PrintWarningWithOrigin(pc, bp,
501 __msan_get_origin(((const char *)x) + offset));
502 if (__msan::flags()->halt_on_error) {
508 int __msan_set_poison_in_malloc(int do_poison) {
509 int old = flags()->poison_in_malloc;
510 flags()->poison_in_malloc = do_poison;
514 int __msan_has_dynamic_component() { return false; }
517 void __msan_clear_on_return() {
518 __msan_param_tls[0] = 0;
521 void __msan_partial_poison(const void* data, void* shadow, uptr size) {
522 internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size);
525 void __msan_load_unpoisoned(const void *src, uptr size, void *dst) {
526 internal_memcpy(dst, src, size);
527 __msan_unpoison(dst, size);
530 void __msan_set_origin(const void *a, uptr size, u32 origin) {
531 if (__msan_get_track_origins()) SetOrigin(a, size, origin);
534 // 'descr' is created at compile time and contains '----' in the beginning.
535 // When we see descr for the first time we replace '----' with a uniq id
536 // and set the origin to (id | (31-th bit)).
537 void __msan_set_alloca_origin(void *a, uptr size, char *descr) {
538 __msan_set_alloca_origin4(a, size, descr, 0);
541 void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
542 static const u32 dash = '-';
543 static const u32 first_timer =
544 dash + (dash << 8) + (dash << 16) + (dash << 24);
545 u32 *id_ptr = (u32*)descr;
546 bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0;
548 if (id == first_timer) {
549 u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
550 CHECK_LT(idx, kNumStackOriginDescrs);
551 StackOriginDescr[idx] = descr + 4;
552 #if SANITIZER_PPC64V1
553 // On PowerPC64 ELFv1, the address of a function actually points to a
554 // three-doubleword data structure with the first field containing
555 // the address of the function's code.
557 pc = *reinterpret_cast<uptr*>(pc);
559 StackOriginPC[idx] = pc;
560 id = Origin::CreateStackOrigin(idx).raw_id();
563 Printf("First time: idx=%d id=%d %s %p \n", idx, id, descr + 4, pc);
566 Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id);
567 __msan_set_origin(a, size, id);
570 u32 __msan_chain_origin(u32 id) {
573 GET_STORE_STACK_TRACE_PC_BP(pc, bp);
574 return ChainOrigin(id, &stack);
577 u32 __msan_get_origin(const void *a) {
578 if (!__msan_get_track_origins()) return 0;
580 uptr aligned = x & ~3ULL;
581 uptr origin_ptr = MEM_TO_ORIGIN(aligned);
582 return *(u32*)origin_ptr;
585 int __msan_origin_is_descendant_or_same(u32 this_id, u32 prev_id) {
586 Origin o = Origin::FromRawId(this_id);
587 while (o.raw_id() != prev_id && o.isChainedOrigin())
588 o = o.getNextChainedOrigin(nullptr);
589 return o.raw_id() == prev_id;
592 u32 __msan_get_umr_origin() {
593 return __msan_origin_tls;
596 u16 __sanitizer_unaligned_load16(const uu16 *p) {
597 *(uu16 *)&__msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p);
598 if (__msan_get_track_origins())
599 __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
602 u32 __sanitizer_unaligned_load32(const uu32 *p) {
603 *(uu32 *)&__msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p);
604 if (__msan_get_track_origins())
605 __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
608 u64 __sanitizer_unaligned_load64(const uu64 *p) {
609 __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p);
610 if (__msan_get_track_origins())
611 __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
614 void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
615 u16 s = *(uu16 *)&__msan_param_tls[1];
616 *(uu16 *)MEM_TO_SHADOW((uptr)p) = s;
617 if (s && __msan_get_track_origins())
618 if (uu32 o = __msan_param_origin_tls[2])
619 SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
622 void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
623 u32 s = *(uu32 *)&__msan_param_tls[1];
624 *(uu32 *)MEM_TO_SHADOW((uptr)p) = s;
625 if (s && __msan_get_track_origins())
626 if (uu32 o = __msan_param_origin_tls[2])
627 SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
630 void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
631 u64 s = __msan_param_tls[1];
632 *(uu64 *)MEM_TO_SHADOW((uptr)p) = s;
633 if (s && __msan_get_track_origins())
634 if (uu32 o = __msan_param_origin_tls[2])
635 SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
639 void __msan_set_death_callback(void (*callback)(void)) {
640 SetUserDieCallback(callback);
643 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
645 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
646 const char* __msan_default_options() { return ""; }
651 SANITIZER_INTERFACE_ATTRIBUTE
652 void __sanitizer_print_stack_trace() {
653 GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());