xref: /freebsd/contrib/llvm-project/compiler-rt/lib/msan/msan.cpp (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 //===-- msan.cpp ----------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of MemorySanitizer.
10 //
11 // MemorySanitizer runtime.
12 //===----------------------------------------------------------------------===//
13 
14 #include "msan.h"
15 #include "msan_chained_origin_depot.h"
16 #include "msan_origin.h"
17 #include "msan_report.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"
31 
32 // ACHTUNG! No system header includes in this file.
33 
34 using namespace __sanitizer;
35 
36 // Globals.
37 static THREADLOCAL int msan_expect_umr = 0;
38 static THREADLOCAL int msan_expected_umr_found = 0;
39 
40 // Function argument shadow. Each argument starts at the next available 8-byte
41 // aligned address.
42 SANITIZER_INTERFACE_ATTRIBUTE
43 THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSize / sizeof(u64)];
44 
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)];
50 
51 SANITIZER_INTERFACE_ATTRIBUTE
52 THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSize / sizeof(u64)];
53 
54 SANITIZER_INTERFACE_ATTRIBUTE
55 THREADLOCAL u32 __msan_retval_origin_tls;
56 
57 SANITIZER_INTERFACE_ATTRIBUTE
58 ALIGNED(16) THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)];
59 
60 SANITIZER_INTERFACE_ATTRIBUTE
61 ALIGNED(16)
62 THREADLOCAL u32 __msan_va_arg_origin_tls[kMsanParamTlsSize / sizeof(u32)];
63 
64 SANITIZER_INTERFACE_ATTRIBUTE
65 THREADLOCAL u64 __msan_va_arg_overflow_size_tls;
66 
67 SANITIZER_INTERFACE_ATTRIBUTE
68 THREADLOCAL u32 __msan_origin_tls;
69 
70 static THREADLOCAL int is_in_symbolizer;
71 
72 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins;
73 
74 int __msan_get_track_origins() {
75   return &__msan_track_origins ? __msan_track_origins : 0;
76 }
77 
78 extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going;
79 
80 namespace __msan {
81 
82 void EnterSymbolizer() { ++is_in_symbolizer; }
83 void ExitSymbolizer()  { --is_in_symbolizer; }
84 bool IsInSymbolizer() { return is_in_symbolizer; }
85 
86 static Flags msan_flags;
87 
88 Flags *flags() {
89   return &msan_flags;
90 }
91 
92 int msan_inited = 0;
93 bool msan_init_is_running;
94 
95 int msan_report_count = 0;
96 
97 // Array of stack origins.
98 // FIXME: make it resizable.
99 static const uptr kNumStackOriginDescrs = 1024 * 1024;
100 static const char *StackOriginDescr[kNumStackOriginDescrs];
101 static uptr StackOriginPC[kNumStackOriginDescrs];
102 static atomic_uint32_t NumStackOriginDescrs;
103 
104 void Flags::SetDefaults() {
105 #define MSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
106 #include "msan_flags.inc"
107 #undef MSAN_FLAG
108 }
109 
110 // keep_going is an old name for halt_on_error,
111 // and it has inverse meaning.
112 class FlagHandlerKeepGoing : public FlagHandlerBase {
113   bool *halt_on_error_;
114 
115  public:
116   explicit FlagHandlerKeepGoing(bool *halt_on_error)
117       : halt_on_error_(halt_on_error) {}
118   bool Parse(const char *value) final {
119     bool tmp;
120     FlagHandler<bool> h(&tmp);
121     if (!h.Parse(value)) return false;
122     *halt_on_error_ = !tmp;
123     return true;
124   }
125   bool Format(char *buffer, uptr size) final {
126     const char *keep_going_str = (*halt_on_error_) ? "false" : "true";
127     return FormatString(buffer, size, keep_going_str);
128   }
129 };
130 
131 static void RegisterMsanFlags(FlagParser *parser, Flags *f) {
132 #define MSAN_FLAG(Type, Name, DefaultValue, Description) \
133   RegisterFlag(parser, #Name, Description, &f->Name);
134 #include "msan_flags.inc"
135 #undef MSAN_FLAG
136 
137   FlagHandlerKeepGoing *fh_keep_going =
138       new (FlagParser::Alloc) FlagHandlerKeepGoing(&f->halt_on_error);
139   parser->RegisterHandler("keep_going", fh_keep_going,
140                           "deprecated, use halt_on_error");
141 }
142 
143 static void InitializeFlags() {
144   SetCommonFlagsDefaults();
145   {
146     CommonFlags cf;
147     cf.CopyFrom(*common_flags());
148     cf.external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH");
149     cf.malloc_context_size = 20;
150     cf.handle_ioctl = true;
151     // FIXME: test and enable.
152     cf.check_printf = false;
153     cf.intercept_tls_get_addr = true;
154     cf.exitcode = 77;
155     OverrideCommonFlags(cf);
156   }
157 
158   Flags *f = flags();
159   f->SetDefaults();
160 
161   FlagParser parser;
162   RegisterMsanFlags(&parser, f);
163   RegisterCommonFlags(&parser);
164 
165 #if MSAN_CONTAINS_UBSAN
166   __ubsan::Flags *uf = __ubsan::flags();
167   uf->SetDefaults();
168 
169   FlagParser ubsan_parser;
170   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
171   RegisterCommonFlags(&ubsan_parser);
172 #endif
173 
174   // Override from user-specified string.
175   if (__msan_default_options)
176     parser.ParseString(__msan_default_options());
177 #if MSAN_CONTAINS_UBSAN
178   const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
179   ubsan_parser.ParseString(ubsan_default_options);
180 #endif
181 
182   parser.ParseStringFromEnv("MSAN_OPTIONS");
183 #if MSAN_CONTAINS_UBSAN
184   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
185 #endif
186 
187   InitializeCommonFlags();
188 
189   if (Verbosity()) ReportUnrecognizedFlags();
190 
191   if (common_flags()->help) parser.PrintFlagDescriptions();
192 
193   // Check if deprecated exit_code MSan flag is set.
194   if (f->exit_code != -1) {
195     if (Verbosity())
196       Printf("MSAN_OPTIONS=exit_code is deprecated! "
197              "Please use MSAN_OPTIONS=exitcode instead.\n");
198     CommonFlags cf;
199     cf.CopyFrom(*common_flags());
200     cf.exitcode = f->exit_code;
201     OverrideCommonFlags(cf);
202   }
203 
204   // Check flag values:
205   if (f->origin_history_size < 0 ||
206       f->origin_history_size > Origin::kMaxDepth) {
207     Printf(
208         "Origin history size invalid: %d. Must be 0 (unlimited) or in [1, %d] "
209         "range.\n",
210         f->origin_history_size, Origin::kMaxDepth);
211     Die();
212   }
213   // Limiting to kStackDepotMaxUseCount / 2 to avoid overflow in
214   // StackDepotHandle::inc_use_count_unsafe.
215   if (f->origin_history_per_stack_limit < 0 ||
216       f->origin_history_per_stack_limit > kStackDepotMaxUseCount / 2) {
217     Printf(
218         "Origin per-stack limit invalid: %d. Must be 0 (unlimited) or in [1, "
219         "%d] range.\n",
220         f->origin_history_per_stack_limit, kStackDepotMaxUseCount / 2);
221     Die();
222   }
223   if (f->store_context_size < 1) f->store_context_size = 1;
224 }
225 
226 void PrintWarning(uptr pc, uptr bp) {
227   PrintWarningWithOrigin(pc, bp, __msan_origin_tls);
228 }
229 
230 void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) {
231   if (msan_expect_umr) {
232     // Printf("Expected UMR\n");
233     __msan_origin_tls = origin;
234     msan_expected_umr_found = 1;
235     return;
236   }
237 
238   ++msan_report_count;
239 
240   GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
241 
242   u32 report_origin =
243     (__msan_get_track_origins() && Origin::isValidId(origin)) ? origin : 0;
244   ReportUMR(&stack, report_origin);
245 
246   if (__msan_get_track_origins() && !Origin::isValidId(origin)) {
247     Printf(
248         "  ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin "
249         "tracking.\n    This could still be a bug in your code, too!\n",
250         origin);
251   }
252 }
253 
254 void UnpoisonParam(uptr n) {
255   internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls));
256 }
257 
258 // Backup MSan runtime TLS state.
259 // Implementation must be async-signal-safe.
260 // Instances of this class may live on the signal handler stack, and data size
261 // may be an issue.
262 void ScopedThreadLocalStateBackup::Backup() {
263   va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls;
264 }
265 
266 void ScopedThreadLocalStateBackup::Restore() {
267   // A lame implementation that only keeps essential state and resets the rest.
268   __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls;
269 
270   internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
271   internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
272   internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
273   internal_memset(__msan_va_arg_origin_tls, 0,
274                   sizeof(__msan_va_arg_origin_tls));
275 
276   if (__msan_get_track_origins()) {
277     internal_memset(&__msan_retval_origin_tls, 0,
278                     sizeof(__msan_retval_origin_tls));
279     internal_memset(__msan_param_origin_tls, 0,
280                     sizeof(__msan_param_origin_tls));
281   }
282 }
283 
284 void UnpoisonThreadLocalState() {
285 }
286 
287 const char *GetStackOriginDescr(u32 id, uptr *pc) {
288   CHECK_LT(id, kNumStackOriginDescrs);
289   if (pc) *pc = StackOriginPC[id];
290   return StackOriginDescr[id];
291 }
292 
293 u32 ChainOrigin(u32 id, StackTrace *stack) {
294   MsanThread *t = GetCurrentThread();
295   if (t && t->InSignalHandler())
296     return id;
297 
298   Origin o = Origin::FromRawId(id);
299   stack->tag = StackTrace::TAG_UNKNOWN;
300   Origin chained = Origin::CreateChainedOrigin(o, stack);
301   return chained.raw_id();
302 }
303 
304 } // namespace __msan
305 
306 void __sanitizer::BufferedStackTrace::UnwindImpl(
307     uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
308   using namespace __msan;
309   MsanThread *t = GetCurrentThread();
310   if (!t || !StackTrace::WillUseFastUnwind(request_fast)) {
311     // Block reports from our interceptors during _Unwind_Backtrace.
312     SymbolizerScope sym_scope;
313     return Unwind(max_depth, pc, bp, context, 0, 0, false);
314   }
315   if (StackTrace::WillUseFastUnwind(request_fast))
316     Unwind(max_depth, pc, bp, nullptr, t->stack_top(), t->stack_bottom(), true);
317   else
318     Unwind(max_depth, pc, 0, context, 0, 0, false);
319 }
320 
321 // Interface.
322 
323 using namespace __msan;
324 
325 #define MSAN_MAYBE_WARNING(type, size)              \
326   void __msan_maybe_warning_##size(type s, u32 o) { \
327     GET_CALLER_PC_BP_SP;                            \
328     (void) sp;                                      \
329     if (UNLIKELY(s)) {                              \
330       PrintWarningWithOrigin(pc, bp, o);            \
331       if (__msan::flags()->halt_on_error) {         \
332         Printf("Exiting\n");                        \
333         Die();                                      \
334       }                                             \
335     }                                               \
336   }
337 
338 MSAN_MAYBE_WARNING(u8, 1)
339 MSAN_MAYBE_WARNING(u16, 2)
340 MSAN_MAYBE_WARNING(u32, 4)
341 MSAN_MAYBE_WARNING(u64, 8)
342 
343 #define MSAN_MAYBE_STORE_ORIGIN(type, size)                       \
344   void __msan_maybe_store_origin_##size(type s, void *p, u32 o) { \
345     if (UNLIKELY(s)) {                                            \
346       if (__msan_get_track_origins() > 1) {                       \
347         GET_CALLER_PC_BP_SP;                                      \
348         (void) sp;                                                \
349         GET_STORE_STACK_TRACE_PC_BP(pc, bp);                      \
350         o = ChainOrigin(o, &stack);                               \
351       }                                                           \
352       *(u32 *)MEM_TO_ORIGIN((uptr)p & ~3UL) = o;                  \
353     }                                                             \
354   }
355 
356 MSAN_MAYBE_STORE_ORIGIN(u8, 1)
357 MSAN_MAYBE_STORE_ORIGIN(u16, 2)
358 MSAN_MAYBE_STORE_ORIGIN(u32, 4)
359 MSAN_MAYBE_STORE_ORIGIN(u64, 8)
360 
361 void __msan_warning() {
362   GET_CALLER_PC_BP_SP;
363   (void)sp;
364   PrintWarning(pc, bp);
365   if (__msan::flags()->halt_on_error) {
366     if (__msan::flags()->print_stats)
367       ReportStats();
368     Printf("Exiting\n");
369     Die();
370   }
371 }
372 
373 void __msan_warning_noreturn() {
374   GET_CALLER_PC_BP_SP;
375   (void)sp;
376   PrintWarning(pc, bp);
377   if (__msan::flags()->print_stats)
378     ReportStats();
379   Printf("Exiting\n");
380   Die();
381 }
382 
383 void __msan_warning_with_origin(u32 origin) {
384   GET_CALLER_PC_BP_SP;
385   (void)sp;
386   PrintWarningWithOrigin(pc, bp, origin);
387   if (__msan::flags()->halt_on_error) {
388     if (__msan::flags()->print_stats)
389       ReportStats();
390     Printf("Exiting\n");
391     Die();
392   }
393 }
394 
395 void __msan_warning_with_origin_noreturn(u32 origin) {
396   GET_CALLER_PC_BP_SP;
397   (void)sp;
398   PrintWarningWithOrigin(pc, bp, origin);
399   if (__msan::flags()->print_stats)
400     ReportStats();
401   Printf("Exiting\n");
402   Die();
403 }
404 
405 static void OnStackUnwind(const SignalContext &sig, const void *,
406                           BufferedStackTrace *stack) {
407   stack->Unwind(StackTrace::GetNextInstructionPc(sig.pc), sig.bp, sig.context,
408                 common_flags()->fast_unwind_on_fatal);
409 }
410 
411 static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) {
412   HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr);
413 }
414 
415 static void MsanCheckFailed(const char *file, int line, const char *cond,
416                             u64 v1, u64 v2) {
417   Report("MemorySanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file,
418          line, cond, (uptr)v1, (uptr)v2);
419   PRINT_CURRENT_STACK_CHECK();
420   Die();
421 }
422 
423 void __msan_init() {
424   CHECK(!msan_init_is_running);
425   if (msan_inited) return;
426   msan_init_is_running = 1;
427   SanitizerToolName = "MemorySanitizer";
428 
429   AvoidCVE_2016_2143();
430 
431   CacheBinaryName();
432   InitializeFlags();
433 
434   // Install tool-specific callbacks in sanitizer_common.
435   SetCheckFailedCallback(MsanCheckFailed);
436 
437   __sanitizer_set_report_path(common_flags()->log_path);
438 
439   InitializeInterceptors();
440   CheckASLR();
441   InitTlsSize();
442   InstallDeadlySignalHandlers(MsanOnDeadlySignal);
443   InstallAtExitHandler(); // Needs __cxa_atexit interceptor.
444 
445   DisableCoreDumperIfNecessary();
446   if (StackSizeIsUnlimited()) {
447     VPrintf(1, "Unlimited stack, doing reexec\n");
448     // A reasonably large stack size. It is bigger than the usual 8Mb, because,
449     // well, the program could have been run with unlimited stack for a reason.
450     SetStackSizeLimitInBytes(32 * 1024 * 1024);
451     ReExec();
452   }
453 
454   __msan_clear_on_return();
455   if (__msan_get_track_origins())
456     VPrintf(1, "msan_track_origins\n");
457   if (!InitShadow(__msan_get_track_origins())) {
458     Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n");
459     Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
460     Printf("FATAL: Disabling ASLR is known to cause this error.\n");
461     Printf("FATAL: If running under GDB, try "
462            "'set disable-randomization off'.\n");
463     DumpProcessMap();
464     Die();
465   }
466 
467   Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer);
468 
469   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
470 
471   MsanTSDInit(MsanTSDDtor);
472 
473   MsanAllocatorInit();
474 
475   MsanThread *main_thread = MsanThread::Create(nullptr, nullptr);
476   SetCurrentThread(main_thread);
477   main_thread->ThreadStart();
478 
479 #if MSAN_CONTAINS_UBSAN
480   __ubsan::InitAsPlugin();
481 #endif
482 
483   VPrintf(1, "MemorySanitizer init done\n");
484 
485   msan_init_is_running = 0;
486   msan_inited = 1;
487 }
488 
489 void __msan_set_keep_going(int keep_going) {
490   flags()->halt_on_error = !keep_going;
491 }
492 
493 void __msan_set_expect_umr(int expect_umr) {
494   if (expect_umr) {
495     msan_expected_umr_found = 0;
496   } else if (!msan_expected_umr_found) {
497     GET_CALLER_PC_BP_SP;
498     (void)sp;
499     GET_FATAL_STACK_TRACE_PC_BP(pc, bp);
500     ReportExpectedUMRNotFound(&stack);
501     Die();
502   }
503   msan_expect_umr = expect_umr;
504 }
505 
506 void __msan_print_shadow(const void *x, uptr size) {
507   if (!MEM_IS_APP(x)) {
508     Printf("Not a valid application address: %p\n", x);
509     return;
510   }
511 
512   DescribeMemoryRange(x, size);
513 }
514 
515 void __msan_dump_shadow(const void *x, uptr size) {
516   if (!MEM_IS_APP(x)) {
517     Printf("Not a valid application address: %p\n", x);
518     return;
519   }
520 
521   unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x);
522   for (uptr i = 0; i < size; i++)
523     Printf("%x%x ", s[i] >> 4, s[i] & 0xf);
524   Printf("\n");
525 }
526 
527 sptr __msan_test_shadow(const void *x, uptr size) {
528   if (!MEM_IS_APP(x)) return -1;
529   unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x);
530   for (uptr i = 0; i < size; ++i)
531     if (s[i])
532       return i;
533   return -1;
534 }
535 
536 void __msan_check_mem_is_initialized(const void *x, uptr size) {
537   if (!__msan::flags()->report_umrs) return;
538   sptr offset = __msan_test_shadow(x, size);
539   if (offset < 0)
540     return;
541 
542   GET_CALLER_PC_BP_SP;
543   (void)sp;
544   ReportUMRInsideAddressRange(__func__, x, size, offset);
545   __msan::PrintWarningWithOrigin(pc, bp,
546                                  __msan_get_origin(((const char *)x) + offset));
547   if (__msan::flags()->halt_on_error) {
548     Printf("Exiting\n");
549     Die();
550   }
551 }
552 
553 int __msan_set_poison_in_malloc(int do_poison) {
554   int old = flags()->poison_in_malloc;
555   flags()->poison_in_malloc = do_poison;
556   return old;
557 }
558 
559 int __msan_has_dynamic_component() { return false; }
560 
561 NOINLINE
562 void __msan_clear_on_return() {
563   __msan_param_tls[0] = 0;
564 }
565 
566 void __msan_partial_poison(const void* data, void* shadow, uptr size) {
567   internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size);
568 }
569 
570 void __msan_load_unpoisoned(const void *src, uptr size, void *dst) {
571   internal_memcpy(dst, src, size);
572   __msan_unpoison(dst, size);
573 }
574 
575 void __msan_set_origin(const void *a, uptr size, u32 origin) {
576   if (__msan_get_track_origins()) SetOrigin(a, size, origin);
577 }
578 
579 // 'descr' is created at compile time and contains '----' in the beginning.
580 // When we see descr for the first time we replace '----' with a uniq id
581 // and set the origin to (id | (31-th bit)).
582 void __msan_set_alloca_origin(void *a, uptr size, char *descr) {
583   __msan_set_alloca_origin4(a, size, descr, 0);
584 }
585 
586 void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
587   static const u32 dash = '-';
588   static const u32 first_timer =
589       dash + (dash << 8) + (dash << 16) + (dash << 24);
590   u32 *id_ptr = (u32*)descr;
591   bool print = false;  // internal_strstr(descr + 4, "AllocaTOTest") != 0;
592   u32 id = *id_ptr;
593   if (id == first_timer) {
594     u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
595     CHECK_LT(idx, kNumStackOriginDescrs);
596     StackOriginDescr[idx] = descr + 4;
597 #if SANITIZER_PPC64V1
598     // On PowerPC64 ELFv1, the address of a function actually points to a
599     // three-doubleword data structure with the first field containing
600     // the address of the function's code.
601     if (pc)
602       pc = *reinterpret_cast<uptr*>(pc);
603 #endif
604     StackOriginPC[idx] = pc;
605     id = Origin::CreateStackOrigin(idx).raw_id();
606     *id_ptr = id;
607     if (print)
608       Printf("First time: idx=%d id=%d %s %p \n", idx, id, descr + 4, pc);
609   }
610   if (print)
611     Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id);
612   __msan_set_origin(a, size, id);
613 }
614 
615 u32 __msan_chain_origin(u32 id) {
616   GET_CALLER_PC_BP_SP;
617   (void)sp;
618   GET_STORE_STACK_TRACE_PC_BP(pc, bp);
619   return ChainOrigin(id, &stack);
620 }
621 
622 u32 __msan_get_origin(const void *a) {
623   if (!__msan_get_track_origins()) return 0;
624   uptr x = (uptr)a;
625   uptr aligned = x & ~3ULL;
626   uptr origin_ptr = MEM_TO_ORIGIN(aligned);
627   return *(u32*)origin_ptr;
628 }
629 
630 int __msan_origin_is_descendant_or_same(u32 this_id, u32 prev_id) {
631   Origin o = Origin::FromRawId(this_id);
632   while (o.raw_id() != prev_id && o.isChainedOrigin())
633     o = o.getNextChainedOrigin(nullptr);
634   return o.raw_id() == prev_id;
635 }
636 
637 u32 __msan_get_umr_origin() {
638   return __msan_origin_tls;
639 }
640 
641 u16 __sanitizer_unaligned_load16(const uu16 *p) {
642   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
643                   sizeof(uu16));
644   if (__msan_get_track_origins())
645     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
646   return *p;
647 }
648 u32 __sanitizer_unaligned_load32(const uu32 *p) {
649   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
650                   sizeof(uu32));
651   if (__msan_get_track_origins())
652     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
653   return *p;
654 }
655 u64 __sanitizer_unaligned_load64(const uu64 *p) {
656   internal_memcpy(&__msan_retval_tls[0], (void *)MEM_TO_SHADOW((uptr)p),
657                   sizeof(uu64));
658   if (__msan_get_track_origins())
659     __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p));
660   return *p;
661 }
662 void __sanitizer_unaligned_store16(uu16 *p, u16 x) {
663   static_assert(sizeof(uu16) == sizeof(u16), "incompatible types");
664   u16 s;
665   internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu16));
666   internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu16));
667   if (s && __msan_get_track_origins())
668     if (uu32 o = __msan_param_origin_tls[2])
669       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
670   *p = x;
671 }
672 void __sanitizer_unaligned_store32(uu32 *p, u32 x) {
673   static_assert(sizeof(uu32) == sizeof(u32), "incompatible types");
674   u32 s;
675   internal_memcpy(&s, &__msan_param_tls[1], sizeof(uu32));
676   internal_memcpy((void *)MEM_TO_SHADOW((uptr)p), &s, sizeof(uu32));
677   if (s && __msan_get_track_origins())
678     if (uu32 o = __msan_param_origin_tls[2])
679       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
680   *p = x;
681 }
682 void __sanitizer_unaligned_store64(uu64 *p, u64 x) {
683   u64 s = __msan_param_tls[1];
684   *(uu64 *)MEM_TO_SHADOW((uptr)p) = s;
685   if (s && __msan_get_track_origins())
686     if (uu32 o = __msan_param_origin_tls[2])
687       SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o);
688   *p = x;
689 }
690 
691 void __msan_set_death_callback(void (*callback)(void)) {
692   SetUserDieCallback(callback);
693 }
694 
695 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
696 extern "C" {
697 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
698 const char* __msan_default_options() { return ""; }
699 }  // extern "C"
700 #endif
701 
702 extern "C" {
703 SANITIZER_INTERFACE_ATTRIBUTE
704 void __sanitizer_print_stack_trace() {
705   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
706   stack.Print();
707 }
708 } // extern "C"
709