| //===-- 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 "sanitizer_common/sanitizer_atomic.h" |
| #include "sanitizer_common/sanitizer_common.h" |
| #include "sanitizer_common/sanitizer_flags.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 "interception/interception.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; |
| |
| static int msan_running_under_dr = 0; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u64 __msan_param_tls[kMsanParamTlsSizeInWords]; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u32 __msan_param_origin_tls[kMsanParamTlsSizeInWords]; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u64 __msan_retval_tls[kMsanRetvalTlsSizeInWords]; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u32 __msan_retval_origin_tls; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u64 __msan_va_arg_tls[kMsanParamTlsSizeInWords]; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u64 __msan_va_arg_overflow_size_tls; |
| |
| SANITIZER_INTERFACE_ATTRIBUTE |
| THREADLOCAL u32 __msan_origin_tls; |
| |
| static THREADLOCAL struct { |
| uptr stack_top, stack_bottom; |
| } __msan_stack_bounds; |
| |
| static THREADLOCAL int is_in_symbolizer; |
| static THREADLOCAL int is_in_loader; |
| |
| 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 { |
| |
| static bool IsRunningUnderDr() { |
| bool result = false; |
| MemoryMappingLayout proc_maps(/*cache_enabled*/true); |
| const sptr kBufSize = 4095; |
| char *filename = (char*)MmapOrDie(kBufSize, __FUNCTION__); |
| while (proc_maps.Next(/* start */0, /* end */0, /* file_offset */0, |
| filename, kBufSize, /* protection */0)) { |
| if (internal_strstr(filename, "libdynamorio") != 0) { |
| result = true; |
| break; |
| } |
| } |
| UnmapOrDie(filename, kBufSize); |
| return result; |
| } |
| |
| void EnterSymbolizer() { ++is_in_symbolizer; } |
| void ExitSymbolizer() { --is_in_symbolizer; } |
| bool IsInSymbolizer() { return is_in_symbolizer; } |
| |
| void EnterLoader() { ++is_in_loader; } |
| void ExitLoader() { --is_in_loader; } |
| |
| extern "C" { |
| SANITIZER_INTERFACE_ATTRIBUTE |
| bool __msan_is_in_loader() { return is_in_loader; } |
| } |
| |
| 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; |
| |
| static void ParseFlagsFromString(Flags *f, const char *str) { |
| ParseCommonFlagsFromString(str); |
| ParseFlag(str, &f->poison_heap_with_zeroes, "poison_heap_with_zeroes"); |
| ParseFlag(str, &f->poison_stack_with_zeroes, "poison_stack_with_zeroes"); |
| ParseFlag(str, &f->poison_in_malloc, "poison_in_malloc"); |
| ParseFlag(str, &f->poison_in_malloc, "poison_in_free"); |
| ParseFlag(str, &f->exit_code, "exit_code"); |
| if (f->exit_code < 0 || f->exit_code > 127) { |
| Printf("Exit code not in [0, 128) range: %d\n", f->exit_code); |
| Die(); |
| } |
| ParseFlag(str, &f->report_umrs, "report_umrs"); |
| ParseFlag(str, &f->verbosity, "verbosity"); |
| ParseFlag(str, &f->wrap_signals, "wrap_signals"); |
| |
| // keep_going is an old name for halt_on_error, |
| // and it has inverse meaning. |
| f->halt_on_error = !f->halt_on_error; |
| ParseFlag(str, &f->halt_on_error, "keep_going"); |
| f->halt_on_error = !f->halt_on_error; |
| ParseFlag(str, &f->halt_on_error, "halt_on_error"); |
| } |
| |
| static void InitializeFlags(Flags *f, const char *options) { |
| CommonFlags *cf = common_flags(); |
| cf->external_symbolizer_path = GetEnv("MSAN_SYMBOLIZER_PATH"); |
| cf->strip_path_prefix = ""; |
| cf->fast_unwind_on_fatal = false; |
| cf->fast_unwind_on_malloc = true; |
| cf->malloc_context_size = 20; |
| cf->handle_ioctl = true; |
| cf->log_path = 0; |
| |
| internal_memset(f, 0, sizeof(*f)); |
| f->poison_heap_with_zeroes = false; |
| f->poison_stack_with_zeroes = false; |
| f->poison_in_malloc = true; |
| f->poison_in_free = true; |
| f->exit_code = 77; |
| f->report_umrs = true; |
| f->verbosity = 0; |
| f->wrap_signals = true; |
| f->halt_on_error = !&__msan_keep_going; |
| |
| // Override from user-specified string. |
| if (__msan_default_options) |
| ParseFlagsFromString(f, __msan_default_options()); |
| ParseFlagsFromString(f, options); |
| } |
| |
| static void GetCurrentStackBounds(uptr *stack_top, uptr *stack_bottom) { |
| if (__msan_stack_bounds.stack_top == 0) { |
| // Break recursion (GetStackTrace -> GetThreadStackTopAndBottom -> |
| // realloc -> GetStackTrace). |
| __msan_stack_bounds.stack_top = __msan_stack_bounds.stack_bottom = 1; |
| GetThreadStackTopAndBottom(/* at_initialization */false, |
| &__msan_stack_bounds.stack_top, |
| &__msan_stack_bounds.stack_bottom); |
| } |
| *stack_top = __msan_stack_bounds.stack_top; |
| *stack_bottom = __msan_stack_bounds.stack_bottom; |
| } |
| |
| void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp, |
| bool fast) { |
| if (!fast) { |
| // Block reports from our interceptors during _Unwind_Backtrace. |
| SymbolizerScope sym_scope; |
| return stack->SlowUnwindStack(pc, max_s); |
| } |
| |
| uptr stack_top, stack_bottom; |
| GetCurrentStackBounds(&stack_top, &stack_bottom); |
| stack->size = 0; |
| stack->trace[0] = pc; |
| stack->max_size = max_s; |
| stack->FastUnwindStack(pc, bp, stack_top, stack_bottom); |
| } |
| |
| void PrintWarning(uptr pc, uptr bp) { |
| PrintWarningWithOrigin(pc, bp, __msan_origin_tls); |
| } |
| |
| bool OriginIsValid(u32 origin) { |
| return origin != 0 && origin != (u32)-1; |
| } |
| |
| 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; |
| |
| StackTrace stack; |
| GetStackTrace(&stack, kStackTraceMax, pc, bp, |
| common_flags()->fast_unwind_on_fatal); |
| |
| u32 report_origin = |
| (__msan_get_track_origins() && OriginIsValid(origin)) ? origin : 0; |
| ReportUMR(&stack, report_origin); |
| |
| if (__msan_get_track_origins() && !OriginIsValid(origin)) { |
| Printf(" ORIGIN: invalid (%x). Might be a bug in MemorySanitizer, " |
| "please report to MemorySanitizer developers.\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_tls)); |
| internal_memset(__msan_param_origin_tls, 0, |
| sizeof(__msan_param_origin_tls)); |
| } |
| } |
| |
| void UnpoisonThreadLocalState() { |
| } |
| |
| const char *GetOriginDescrIfStack(u32 id, uptr *pc) { |
| if ((id >> 31) == 0) return 0; |
| id &= (1U << 31) - 1; |
| CHECK_LT(id, kNumStackOriginDescrs); |
| if (pc) *pc = StackOriginPC[id]; |
| return StackOriginDescr[id]; |
| } |
| |
| } // namespace __msan |
| |
| // Interface. |
| |
| using namespace __msan; |
| |
| void __msan_warning() { |
| GET_CALLER_PC_BP_SP; |
| (void)sp; |
| PrintWarning(pc, bp); |
| if (__msan::flags()->halt_on_error) { |
| Printf("Exiting\n"); |
| Die(); |
| } |
| } |
| |
| void __msan_warning_noreturn() { |
| GET_CALLER_PC_BP_SP; |
| (void)sp; |
| PrintWarning(pc, bp); |
| Printf("Exiting\n"); |
| Die(); |
| } |
| |
| void __msan_init() { |
| if (msan_inited) return; |
| msan_init_is_running = 1; |
| SanitizerToolName = "MemorySanitizer"; |
| |
| SetDieCallback(MsanDie); |
| InitTlsSize(); |
| InitializeInterceptors(); |
| InstallAtExitHandler(); // Needs __cxa_atexit interceptor. |
| |
| if (MSAN_REPLACE_OPERATORS_NEW_AND_DELETE) |
| ReplaceOperatorsNewAndDelete(); |
| const char *msan_options = GetEnv("MSAN_OPTIONS"); |
| InitializeFlags(&msan_flags, msan_options); |
| __sanitizer_set_report_path(common_flags()->log_path); |
| if (StackSizeIsUnlimited()) { |
| if (flags()->verbosity) |
| Printf("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(); |
| } |
| |
| if (flags()->verbosity) |
| Printf("MSAN_OPTIONS: %s\n", msan_options ? msan_options : "<empty>"); |
| |
| msan_running_under_dr = IsRunningUnderDr(); |
| __msan_clear_on_return(); |
| if (__msan_get_track_origins() && flags()->verbosity > 0) |
| Printf("msan_track_origins\n"); |
| if (!InitShadow(/* prot1 */ false, /* prot2 */ true, /* map_shadow */ true, |
| __msan_get_track_origins())) { |
| // FIXME: prot1 = false is only required when running under DR. |
| 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(); |
| } |
| |
| const char *external_symbolizer = common_flags()->external_symbolizer_path; |
| bool symbolizer_started = |
| getSymbolizer()->InitializeExternal(external_symbolizer); |
| if (external_symbolizer && external_symbolizer[0]) { |
| CHECK(symbolizer_started); |
| } |
| |
| GetThreadStackTopAndBottom(/* at_initialization */true, |
| &__msan_stack_bounds.stack_top, |
| &__msan_stack_bounds.stack_bottom); |
| if (flags()->verbosity) |
| Printf("MemorySanitizer init done\n"); |
| msan_init_is_running = 0; |
| msan_inited = 1; |
| } |
| |
| void __msan_set_exit_code(int exit_code) { |
| flags()->exit_code = exit_code; |
| } |
| |
| 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; |
| StackTrace stack; |
| GetStackTrace(&stack, kStackTraceMax, pc, bp, |
| common_flags()->fast_unwind_on_fatal); |
| ReportExpectedUMRNotFound(&stack); |
| Die(); |
| } |
| msan_expect_umr = expect_umr; |
| } |
| |
| void __msan_print_shadow(const void *x, uptr size) { |
| unsigned char *s = (unsigned char*)MEM_TO_SHADOW(x); |
| u32 *o = (u32*)MEM_TO_ORIGIN(x); |
| for (uptr i = 0; i < size; i++) { |
| Printf("%x%x ", s[i] >> 4, s[i] & 0xf); |
| } |
| Printf("\n"); |
| if (__msan_get_track_origins()) { |
| for (uptr i = 0; i < size / 4; i++) { |
| Printf(" o: %x ", o[i]); |
| } |
| Printf("\n"); |
| } |
| } |
| |
| void __msan_print_param_shadow() { |
| for (int i = 0; i < 16; i++) { |
| Printf("#%d:%zx ", i, __msan_param_tls[i]); |
| } |
| Printf("\n"); |
| } |
| |
| sptr __msan_test_shadow(const void *x, uptr size) { |
| unsigned char *s = (unsigned char*)MEM_TO_SHADOW((uptr)x); |
| for (uptr i = 0; i < size; ++i) |
| if (s[i]) |
| return i; |
| return -1; |
| } |
| |
| 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 msan_running_under_dr; |
| } |
| |
| NOINLINE |
| void __msan_clear_on_return() { |
| __msan_param_tls[0] = 0; |
| } |
| |
| static void* get_tls_base() { |
| u64 p; |
| asm("mov %%fs:0, %0" |
| : "=r"(p) ::); |
| return (void*)p; |
| } |
| |
| int __msan_get_retval_tls_offset() { |
| // volatile here is needed to avoid UB, because the compiler thinks that we |
| // are doing address arithmetics on unrelated pointers, and takes some |
| // shortcuts |
| volatile sptr retval_tls_p = (sptr)&__msan_retval_tls; |
| volatile sptr tls_base_p = (sptr)get_tls_base(); |
| return retval_tls_p - tls_base_p; |
| } |
| |
| int __msan_get_param_tls_offset() { |
| // volatile here is needed to avoid UB, because the compiler thinks that we |
| // are doing address arithmetics on unrelated pointers, and takes some |
| // shortcuts |
| volatile sptr param_tls_p = (sptr)&__msan_param_tls; |
| volatile sptr tls_base_p = (sptr)get_tls_base(); |
| return param_tls_p - tls_base_p; |
| } |
| |
| 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(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) { |
| // Origin mapping is 4 bytes per 4 bytes of application memory. |
| // Here we extend the range such that its left and right bounds are both |
| // 4 byte aligned. |
| if (!__msan_get_track_origins()) return; |
| uptr x = MEM_TO_ORIGIN((uptr)a); |
| uptr beg = x & ~3UL; // align down. |
| uptr end = (x + size + 3) & ~3UL; // align up. |
| u64 origin64 = ((u64)origin << 32) | origin; |
| // This is like memset, but the value is 32-bit. We unroll by 2 two write |
| // 64-bits at once. May want to unroll further to get 128-bit stores. |
| if (beg & 7ULL) { |
| *(u32*)beg = origin; |
| beg += 4; |
| } |
| for (uptr addr = beg; addr < (end & ~7UL); addr += 8) |
| *(u64*)addr = origin64; |
| if (end & 7ULL) |
| *(u32*)(end - 4) = 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, const char *descr) { |
| __msan_set_alloca_origin4(a, size, descr, 0); |
| } |
| |
| void __msan_set_alloca_origin4(void *a, uptr size, const 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) { |
| id = atomic_fetch_add(&NumStackOriginDescrs, |
| 1, memory_order_relaxed); |
| *id_ptr = id; |
| CHECK_LT(id, kNumStackOriginDescrs); |
| StackOriginDescr[id] = descr + 4; |
| StackOriginPC[id] = pc; |
| if (print) |
| Printf("First time: id=%d %s %p \n", id, descr + 4, pc); |
| } |
| id |= 1U << 31; |
| if (print) |
| Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id); |
| __msan_set_origin(a, size, id); |
| } |
| |
| const char *__msan_get_origin_descr_if_stack(u32 id) { |
| return GetOriginDescrIfStack(id, 0); |
| } |
| |
| 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; |
| } |
| |
| u32 __msan_get_umr_origin() { |
| return __msan_origin_tls; |
| } |
| |
| u16 __sanitizer_unaligned_load16(const uu16 *p) { |
| __msan_retval_tls[0] = *(uu16 *)MEM_TO_SHADOW((uptr)p); |
| return *p; |
| } |
| u32 __sanitizer_unaligned_load32(const uu32 *p) { |
| __msan_retval_tls[0] = *(uu32 *)MEM_TO_SHADOW((uptr)p); |
| return *p; |
| } |
| u64 __sanitizer_unaligned_load64(const uu64 *p) { |
| __msan_retval_tls[0] = *(uu64 *)MEM_TO_SHADOW((uptr)p); |
| return *p; |
| } |
| void __sanitizer_unaligned_store16(uu16 *p, u16 x) { |
| *(uu16 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; |
| *p = x; |
| } |
| void __sanitizer_unaligned_store32(uu32 *p, u32 x) { |
| *(uu32 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; |
| *p = x; |
| } |
| void __sanitizer_unaligned_store64(uu64 *p, u64 x) { |
| *(uu64 *)MEM_TO_SHADOW((uptr)p) = __msan_param_tls[1]; |
| *p = x; |
| } |
| |
| #if !SANITIZER_SUPPORTS_WEAK_HOOKS |
| extern "C" { |
| SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE |
| const char* __msan_default_options() { return ""; } |
| } // extern "C" |
| #endif |
| |