//===-- msan.cc -----------------------------------------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file is a part of MemorySanitizer. // // MemorySanitizer runtime. //===----------------------------------------------------------------------===// #include "msan.h" #include "msan_chained_origin_depot.h" #include "msan_origin.h" #include "msan_report.h" #include "msan_thread.h" #include "msan_poisoning.h" #include "sanitizer_common/sanitizer_atomic.h" #include "sanitizer_common/sanitizer_common.h" #include "sanitizer_common/sanitizer_flags.h" #include "sanitizer_common/sanitizer_flag_parser.h" #include "sanitizer_common/sanitizer_libc.h" #include "sanitizer_common/sanitizer_procmaps.h" #include "sanitizer_common/sanitizer_stacktrace.h" #include "sanitizer_common/sanitizer_symbolizer.h" #include "sanitizer_common/sanitizer_stackdepot.h" #include "ubsan/ubsan_flags.h" #include "ubsan/ubsan_init.h" // ACHTUNG! No system header includes in this file. using namespace __sanitizer; // Globals. static THREADLOCAL int msan_expect_umr = 0; static THREADLOCAL int msan_expected_umr_found = 0; // Function argument shadow. Each argument starts at the next available 8-byte // aligned address. SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSize / sizeof(u64)]; // Function argument origin. Each argument starts at the same offset as the // corresponding shadow in (__msan_param_tls). Slightly weird, but changing this // would break compatibility with older prebuilt binaries. SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSize / sizeof(u32)]; SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSize / sizeof(u64)]; SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u32 __msan_retval_origin_tls; SANITIZER_INTERFACE_ATTRIBUTE ALIGNED(16) THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSize / sizeof(u64)]; SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u64 __msan_va_arg_overflow_size_tls; SANITIZER_INTERFACE_ATTRIBUTE THREADLOCAL u32 __msan_origin_tls; static THREADLOCAL int is_in_symbolizer; extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_track_origins; int __msan_get_track_origins() { return &__msan_track_origins ? __msan_track_origins : 0; } extern "C" SANITIZER_WEAK_ATTRIBUTE const int __msan_keep_going; namespace __msan { void EnterSymbolizer() { ++is_in_symbolizer; } void ExitSymbolizer() { --is_in_symbolizer; } bool IsInSymbolizer() { return is_in_symbolizer; } static Flags msan_flags; Flags *flags() { return &msan_flags; } int msan_inited = 0; bool msan_init_is_running; int msan_report_count = 0; // Array of stack origins. // FIXME: make it resizable. static const uptr kNumStackOriginDescrs = 1024 * 1024; static const char *StackOriginDescr[kNumStackOriginDescrs]; static uptr StackOriginPC[kNumStackOriginDescrs]; static atomic_uint32_t NumStackOriginDescrs; void Flags::SetDefaults() { #define MSAN_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue; #include "msan_flags.inc" #undef MSAN_FLAG } // keep_going is an old name for halt_on_error, // and it has inverse meaning. class FlagHandlerKeepGoing : public FlagHandlerBase { bool *halt_on_error_; public: explicit FlagHandlerKeepGoing(bool *halt_on_error) : halt_on_error_(halt_on_error) {} bool Parse(const char *value) final { bool tmp; FlagHandler h(&tmp); if (!h.Parse(value)) return false; *halt_on_error_ = !tmp; return true; } }; static void RegisterMsanFlags(FlagParser *parser, Flags *f) { #define MSAN_FLAG(Type, Name, DefaultValue, Description) \ RegisterFlag(parser, #Name, Description, &f->Name); #include "msan_flags.inc" #undef MSAN_FLAG FlagHandlerKeepGoing *fh_keep_going = new (FlagParser::Alloc) // NOLINT FlagHandlerKeepGoing(&f->halt_on_error); parser->RegisterHandler("keep_going", fh_keep_going, "deprecated, use halt_on_error"); } static void InitializeFlags() { SetCommonFlagsDefaults(); { CommonFlags cf; cf.CopyFrom(*common_flags()); cf.external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); cf.malloc_context_size = 20; cf.handle_ioctl = true; // FIXME: test and enable. cf.check_printf = false; cf.intercept_tls_get_addr = true; cf.exitcode = 77; OverrideCommonFlags(cf); } Flags *f = flags(); f->SetDefaults(); FlagParser parser; RegisterMsanFlags(&parser, f); RegisterCommonFlags(&parser); #if MSAN_CONTAINS_UBSAN __ubsan::Flags *uf = __ubsan::flags(); uf->SetDefaults(); FlagParser ubsan_parser; __ubsan::RegisterUbsanFlags(&ubsan_parser, uf); RegisterCommonFlags(&ubsan_parser); #endif // Override from user-specified string. if (__msan_default_options) parser.ParseString(__msan_default_options()); #if MSAN_CONTAINS_UBSAN const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions(); ubsan_parser.ParseString(ubsan_default_options); #endif const char *msan_options = GetEnv("MSAN_OPTIONS"); parser.ParseString(msan_options); #if MSAN_CONTAINS_UBSAN ubsan_parser.ParseString(GetEnv("UBSAN_OPTIONS")); #endif VPrintf(1, "MSAN_OPTIONS: %s\n", msan_options ? msan_options : ""); InitializeCommonFlags(); if (Verbosity()) ReportUnrecognizedFlags(); if (common_flags()->help) parser.PrintFlagDescriptions(); // Check if deprecated exit_code MSan flag is set. if (f->exit_code != -1) { if (Verbosity()) Printf("MSAN_OPTIONS=exit_code is deprecated! " "Please use MSAN_OPTIONS=exitcode instead.\n"); CommonFlags cf; cf.CopyFrom(*common_flags()); cf.exitcode = f->exit_code; OverrideCommonFlags(cf); } // Check flag values: if (f->origin_history_size < 0 || f->origin_history_size > Origin::kMaxDepth) { Printf( "Origin history size invalid: %d. Must be 0 (unlimited) or in [1, %d] " "range.\n", f->origin_history_size, Origin::kMaxDepth); Die(); } // Limiting to kStackDepotMaxUseCount / 2 to avoid overflow in // StackDepotHandle::inc_use_count_unsafe. if (f->origin_history_per_stack_limit < 0 || f->origin_history_per_stack_limit > kStackDepotMaxUseCount / 2) { Printf( "Origin per-stack limit invalid: %d. Must be 0 (unlimited) or in [1, " "%d] range.\n", f->origin_history_per_stack_limit, kStackDepotMaxUseCount / 2); Die(); } if (f->store_context_size < 1) f->store_context_size = 1; } void GetStackTrace(BufferedStackTrace *stack, uptr max_s, uptr pc, uptr bp, void *context, bool request_fast_unwind) { MsanThread *t = GetCurrentThread(); if (!t || !StackTrace::WillUseFastUnwind(request_fast_unwind)) { // Block reports from our interceptors during _Unwind_Backtrace. SymbolizerScope sym_scope; return stack->Unwind(max_s, pc, bp, context, 0, 0, request_fast_unwind); } stack->Unwind(max_s, pc, bp, context, t->stack_top(), t->stack_bottom(), request_fast_unwind); } void PrintWarning(uptr pc, uptr bp) { PrintWarningWithOrigin(pc, bp, __msan_origin_tls); } void PrintWarningWithOrigin(uptr pc, uptr bp, u32 origin) { if (msan_expect_umr) { // Printf("Expected UMR\n"); __msan_origin_tls = origin; msan_expected_umr_found = 1; return; } ++msan_report_count; GET_FATAL_STACK_TRACE_PC_BP(pc, bp); u32 report_origin = (__msan_get_track_origins() && Origin::isValidId(origin)) ? origin : 0; ReportUMR(&stack, report_origin); if (__msan_get_track_origins() && !Origin::isValidId(origin)) { Printf( " ORIGIN: invalid (%x). Might be a bug in MemorySanitizer origin " "tracking.\n This could still be a bug in your code, too!\n", origin); } } void UnpoisonParam(uptr n) { internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls)); } // Backup MSan runtime TLS state. // Implementation must be async-signal-safe. // Instances of this class may live on the signal handler stack, and data size // may be an issue. void ScopedThreadLocalStateBackup::Backup() { va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls; } void ScopedThreadLocalStateBackup::Restore() { // A lame implementation that only keeps essential state and resets the rest. __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls; internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls)); internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls)); internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls)); if (__msan_get_track_origins()) { internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_origin_tls)); internal_memset(__msan_param_origin_tls, 0, sizeof(__msan_param_origin_tls)); } } void UnpoisonThreadLocalState() { } const char *GetStackOriginDescr(u32 id, uptr *pc) { CHECK_LT(id, kNumStackOriginDescrs); if (pc) *pc = StackOriginPC[id]; return StackOriginDescr[id]; } u32 ChainOrigin(u32 id, StackTrace *stack) { MsanThread *t = GetCurrentThread(); if (t && t->InSignalHandler()) return id; Origin o = Origin::FromRawId(id); stack->tag = StackTrace::TAG_UNKNOWN; Origin chained = Origin::CreateChainedOrigin(o, stack); return chained.raw_id(); } } // namespace __msan // Interface. using namespace __msan; #define MSAN_MAYBE_WARNING(type, size) \ void __msan_maybe_warning_##size(type s, u32 o) { \ GET_CALLER_PC_BP_SP; \ (void) sp; \ if (UNLIKELY(s)) { \ PrintWarningWithOrigin(pc, bp, o); \ if (__msan::flags()->halt_on_error) { \ Printf("Exiting\n"); \ Die(); \ } \ } \ } MSAN_MAYBE_WARNING(u8, 1) MSAN_MAYBE_WARNING(u16, 2) MSAN_MAYBE_WARNING(u32, 4) MSAN_MAYBE_WARNING(u64, 8) #define MSAN_MAYBE_STORE_ORIGIN(type, size) \ void __msan_maybe_store_origin_##size(type s, void *p, u32 o) { \ if (UNLIKELY(s)) { \ if (__msan_get_track_origins() > 1) { \ GET_CALLER_PC_BP_SP; \ (void) sp; \ GET_STORE_STACK_TRACE_PC_BP(pc, bp); \ o = ChainOrigin(o, &stack); \ } \ *(u32 *)MEM_TO_ORIGIN((uptr)p & ~3UL) = o; \ } \ } MSAN_MAYBE_STORE_ORIGIN(u8, 1) MSAN_MAYBE_STORE_ORIGIN(u16, 2) MSAN_MAYBE_STORE_ORIGIN(u32, 4) MSAN_MAYBE_STORE_ORIGIN(u64, 8) void __msan_warning() { GET_CALLER_PC_BP_SP; (void)sp; PrintWarning(pc, bp); if (__msan::flags()->halt_on_error) { if (__msan::flags()->print_stats) ReportStats(); Printf("Exiting\n"); Die(); } } void __msan_warning_noreturn() { GET_CALLER_PC_BP_SP; (void)sp; PrintWarning(pc, bp); if (__msan::flags()->print_stats) ReportStats(); Printf("Exiting\n"); Die(); } static void OnStackUnwind(const SignalContext &sig, const void *, BufferedStackTrace *stack) { GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, sig.context, common_flags()->fast_unwind_on_fatal); } static void MsanOnDeadlySignal(int signo, void *siginfo, void *context) { HandleDeadlySignal(siginfo, context, GetTid(), &OnStackUnwind, nullptr); } static void MsanCheckFailed(const char *file, int line, const char *cond, u64 v1, u64 v2) { Report("MemorySanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file, line, cond, (uptr)v1, (uptr)v2); PRINT_CURRENT_STACK_CHECK(); Die(); } void __msan_init() { CHECK(!msan_init_is_running); if (msan_inited) return; msan_init_is_running = 1; SanitizerToolName = "MemorySanitizer"; AvoidCVE_2016_2143(); CacheBinaryName(); CheckASLR(); InitializeFlags(); // Install tool-specific callbacks in sanitizer_common. SetCheckFailedCallback(MsanCheckFailed); __sanitizer_set_report_path(common_flags()->log_path); InitializeInterceptors(); InitTlsSize(); InstallDeadlySignalHandlers(MsanOnDeadlySignal); InstallAtExitHandler(); // Needs __cxa_atexit interceptor. DisableCoreDumperIfNecessary(); if (StackSizeIsUnlimited()) { VPrintf(1, "Unlimited stack, doing reexec\n"); // A reasonably large stack size. It is bigger than the usual 8Mb, because, // well, the program could have been run with unlimited stack for a reason. SetStackSizeLimitInBytes(32 * 1024 * 1024); ReExec(); } __msan_clear_on_return(); if (__msan_get_track_origins()) VPrintf(1, "msan_track_origins\n"); if (!InitShadow(__msan_get_track_origins())) { Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n"); Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n"); Printf("FATAL: Disabling ASLR is known to cause this error.\n"); Printf("FATAL: If running under GDB, try " "'set disable-randomization off'.\n"); DumpProcessMap(); Die(); } Symbolizer::GetOrInit()->AddHooks(EnterSymbolizer, ExitSymbolizer); InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir); MsanTSDInit(MsanTSDDtor); MsanAllocatorInit(); MsanThread *main_thread = MsanThread::Create(nullptr, nullptr); SetCurrentThread(main_thread); main_thread->ThreadStart(); #if MSAN_CONTAINS_UBSAN __ubsan::InitAsPlugin(); #endif VPrintf(1, "MemorySanitizer init done\n"); msan_init_is_running = 0; msan_inited = 1; } void __msan_set_keep_going(int keep_going) { flags()->halt_on_error = !keep_going; } void __msan_set_expect_umr(int expect_umr) { if (expect_umr) { msan_expected_umr_found = 0; } else if (!msan_expected_umr_found) { GET_CALLER_PC_BP_SP; (void)sp; GET_FATAL_STACK_TRACE_PC_BP(pc, bp); ReportExpectedUMRNotFound(&stack); Die(); } msan_expect_umr = expect_umr; } void __msan_print_shadow(const void *x, uptr size) { if (!MEM_IS_APP(x)) { Printf("Not a valid application address: %p\n", x); return; } DescribeMemoryRange(x, size); } void __msan_dump_shadow(const void *x, uptr size) { if (!MEM_IS_APP(x)) { Printf("Not a valid application address: %p\n", x); return; } unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); for (uptr i = 0; i < size; i++) Printf("%x%x ", s[i] >> 4, s[i] & 0xf); Printf("\n"); } sptr __msan_test_shadow(const void *x, uptr size) { if (!MEM_IS_APP(x)) return -1; unsigned char *s = (unsigned char *)MEM_TO_SHADOW((uptr)x); for (uptr i = 0; i < size; ++i) if (s[i]) return i; return -1; } void __msan_check_mem_is_initialized(const void *x, uptr size) { if (!__msan::flags()->report_umrs) return; sptr offset = __msan_test_shadow(x, size); if (offset < 0) return; GET_CALLER_PC_BP_SP; (void)sp; ReportUMRInsideAddressRange(__func__, x, size, offset); __msan::PrintWarningWithOrigin(pc, bp, __msan_get_origin(((const char *)x) + offset)); if (__msan::flags()->halt_on_error) { Printf("Exiting\n"); Die(); } } int __msan_set_poison_in_malloc(int do_poison) { int old = flags()->poison_in_malloc; flags()->poison_in_malloc = do_poison; return old; } int __msan_has_dynamic_component() { return false; } NOINLINE void __msan_clear_on_return() { __msan_param_tls[0] = 0; } void __msan_partial_poison(const void* data, void* shadow, uptr size) { internal_memcpy((void*)MEM_TO_SHADOW((uptr)data), shadow, size); } void __msan_load_unpoisoned(const void *src, uptr size, void *dst) { internal_memcpy(dst, src, size); __msan_unpoison(dst, size); } void __msan_set_origin(const void *a, uptr size, u32 origin) { if (__msan_get_track_origins()) SetOrigin(a, size, origin); } // 'descr' is created at compile time and contains '----' in the beginning. // When we see descr for the first time we replace '----' with a uniq id // and set the origin to (id | (31-th bit)). void __msan_set_alloca_origin(void *a, uptr size, char *descr) { __msan_set_alloca_origin4(a, size, descr, 0); } void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) { static const u32 dash = '-'; static const u32 first_timer = dash + (dash << 8) + (dash << 16) + (dash << 24); u32 *id_ptr = (u32*)descr; bool print = false; // internal_strstr(descr + 4, "AllocaTOTest") != 0; u32 id = *id_ptr; if (id == first_timer) { u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed); CHECK_LT(idx, kNumStackOriginDescrs); StackOriginDescr[idx] = descr + 4; #if SANITIZER_PPC64V1 // On PowerPC64 ELFv1, the address of a function actually points to a // three-doubleword data structure with the first field containing // the address of the function's code. if (pc) pc = *reinterpret_cast(pc); #endif StackOriginPC[idx] = pc; id = Origin::CreateStackOrigin(idx).raw_id(); *id_ptr = id; if (print) Printf("First time: idx=%d id=%d %s %p \n", idx, id, descr + 4, pc); } if (print) Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); __msan_set_origin(a, size, id); } u32 __msan_chain_origin(u32 id) { GET_CALLER_PC_BP_SP; (void)sp; GET_STORE_STACK_TRACE_PC_BP(pc, bp); return ChainOrigin(id, &stack); } u32 __msan_get_origin(const void *a) { if (!__msan_get_track_origins()) return 0; uptr x = (uptr)a; uptr aligned = x & ~3ULL; uptr origin_ptr = MEM_TO_ORIGIN(aligned); return *(u32*)origin_ptr; } int __msan_origin_is_descendant_or_same(u32 this_id, u32 prev_id) { Origin o = Origin::FromRawId(this_id); while (o.raw_id() != prev_id && o.isChainedOrigin()) o = o.getNextChainedOrigin(nullptr); return o.raw_id() == prev_id; } u32 __msan_get_umr_origin() { return __msan_origin_tls; } u16 __sanitizer_unaligned_load16(const uu16 *p) { *(uu16 *)&__msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); if (__msan_get_track_origins()) __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p)); return *p; } u32 __sanitizer_unaligned_load32(const uu32 *p) { *(uu32 *)&__msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); if (__msan_get_track_origins()) __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p)); return *p; } u64 __sanitizer_unaligned_load64(const uu64 *p) { __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); if (__msan_get_track_origins()) __msan_retval_origin_tls = GetOriginIfPoisoned((uptr)p, sizeof(*p)); return *p; } void __sanitizer_unaligned_store16(uu16 *p, u16 x) { u16 s = *(uu16 *)&__msan_param_tls[1]; *(uu16 *)MEM_TO_SHADOW((uptr)p) = s; if (s && __msan_get_track_origins()) if (uu32 o = __msan_param_origin_tls[2]) SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o); *p = x; } void __sanitizer_unaligned_store32(uu32 *p, u32 x) { u32 s = *(uu32 *)&__msan_param_tls[1]; *(uu32 *)MEM_TO_SHADOW((uptr)p) = s; if (s && __msan_get_track_origins()) if (uu32 o = __msan_param_origin_tls[2]) SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o); *p = x; } void __sanitizer_unaligned_store64(uu64 *p, u64 x) { u64 s = __msan_param_tls[1]; *(uu64 *)MEM_TO_SHADOW((uptr)p) = s; if (s && __msan_get_track_origins()) if (uu32 o = __msan_param_origin_tls[2]) SetOriginIfPoisoned((uptr)p, (uptr)&s, sizeof(s), o); *p = x; } void __msan_set_death_callback(void (*callback)(void)) { SetUserDieCallback(callback); } #if !SANITIZER_SUPPORTS_WEAK_HOOKS extern "C" { SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE const char* __msan_default_options() { return ""; } } // extern "C" #endif extern "C" { SANITIZER_INTERFACE_ATTRIBUTE void __sanitizer_print_stack_trace() { GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME()); stack.Print(); } } // extern "C"