asan_rtl.cc revision 95f630ae40cef78fb03b18110eff43bcf8d1c040 
1//===-- asan_rtl.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 AddressSanitizer, an address sanity checker.
11//
12// Main file of the ASan run-time library.
13//===----------------------------------------------------------------------===//
14#include "asan_allocator.h"
15#include "asan_interceptors.h"
16#include "asan_internal.h"
17#include "asan_mapping.h"
18#include "asan_report.h"
19#include "asan_stack.h"
20#include "asan_stats.h"
21#include "asan_thread.h"
22#include "asan_thread_registry.h"
23#include "sanitizer/asan_interface.h"
24#include "sanitizer_common/sanitizer_atomic.h"
25#include "sanitizer_common/sanitizer_flags.h"
26#include "sanitizer_common/sanitizer_libc.h"
27#include "sanitizer_common/sanitizer_symbolizer.h"
28
29namespace __asan {
30
31static void AsanDie() {
32  static atomic_uint32_t num_calls;
33  if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
34    // Don't die twice - run a busy loop.
35    while (1) { }
36  }
37  if (flags()->sleep_before_dying) {
38    Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
39    SleepForSeconds(flags()->sleep_before_dying);
40  }
41  if (flags()->unmap_shadow_on_exit)
42    UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
43  if (death_callback)
44    death_callback();
45  if (flags()->abort_on_error)
46    Abort();
47  Exit(flags()->exitcode);
48}
49
50static void AsanCheckFailed(const char *file, int line, const char *cond,
51                            u64 v1, u64 v2) {
52  Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
53             file, line, cond, (uptr)v1, (uptr)v2);
54  // FIXME: check for infinite recursion without a thread-local counter here.
55  PRINT_CURRENT_STACK();
56  Die();
57}
58
59// -------------------------- Flags ------------------------- {{{1
60static const int kDeafultMallocContextSize = 30;
61
62static Flags asan_flags;
63
64Flags *flags() {
65  return &asan_flags;
66}
67
68static const char *MaybeCallAsanDefaultOptions() {
69  return (&__asan_default_options) ? __asan_default_options() : "";
70}
71
72static void ParseFlagsFromString(Flags *f, const char *str) {
73  ParseFlag(str, &f->quarantine_size, "quarantine_size");
74  ParseFlag(str, &f->symbolize, "symbolize");
75  ParseFlag(str, &f->verbosity, "verbosity");
76  ParseFlag(str, &f->redzone, "redzone");
77  CHECK(f->redzone >= 16);
78  CHECK(IsPowerOfTwo(f->redzone));
79
80  ParseFlag(str, &f->debug, "debug");
81  ParseFlag(str, &f->report_globals, "report_globals");
82  ParseFlag(str, &f->check_initialization_order, "initialization_order");
83  ParseFlag(str, &f->malloc_context_size, "malloc_context_size");
84  CHECK((uptr)f->malloc_context_size <= kStackTraceMax);
85
86  ParseFlag(str, &f->replace_str, "replace_str");
87  ParseFlag(str, &f->replace_intrin, "replace_intrin");
88  ParseFlag(str, &f->replace_cfallocator, "replace_cfallocator");
89  ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
90  ParseFlag(str, &f->use_fake_stack, "use_fake_stack");
91  ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
92  ParseFlag(str, &f->exitcode, "exitcode");
93  ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
94  ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
95  ParseFlag(str, &f->handle_segv, "handle_segv");
96  ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
97  ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
98  ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
99  ParseFlag(str, &f->abort_on_error, "abort_on_error");
100  ParseFlag(str, &f->print_stats, "print_stats");
101  ParseFlag(str, &f->print_legend, "print_legend");
102  ParseFlag(str, &f->atexit, "atexit");
103  ParseFlag(str, &f->disable_core, "disable_core");
104  ParseFlag(str, &f->strip_path_prefix, "strip_path_prefix");
105  ParseFlag(str, &f->allow_reexec, "allow_reexec");
106  ParseFlag(str, &f->print_full_thread_history, "print_full_thread_history");
107  ParseFlag(str, &f->log_path, "log_path");
108  ParseFlag(str, &f->fast_unwind_on_fatal, "fast_unwind_on_fatal");
109  ParseFlag(str, &f->fast_unwind_on_malloc, "fast_unwind_on_malloc");
110  ParseFlag(str, &f->poison_heap, "poison_heap");
111  ParseFlag(str, &f->alloc_dealloc_mismatch, "alloc_dealloc_mismatch");
112  ParseFlag(str, &f->use_stack_depot, "use_stack_depot");
113}
114
115void InitializeFlags(Flags *f, const char *env) {
116  internal_memset(f, 0, sizeof(*f));
117
118  f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
119  f->symbolize = false;
120  f->verbosity = 0;
121  f->redzone = ASAN_ALLOCATOR_VERSION == 2 ? 16 : (ASAN_LOW_MEMORY) ? 64 : 128;
122  f->debug = false;
123  f->report_globals = 1;
124  f->check_initialization_order = true;
125  f->malloc_context_size = kDeafultMallocContextSize;
126  f->replace_str = true;
127  f->replace_intrin = true;
128  f->replace_cfallocator = true;
129  f->mac_ignore_invalid_free = false;
130  f->use_fake_stack = true;
131  f->max_malloc_fill_size = 0;
132  f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
133  f->allow_user_poisoning = true;
134  f->sleep_before_dying = 0;
135  f->handle_segv = ASAN_NEEDS_SEGV;
136  f->use_sigaltstack = false;
137  f->check_malloc_usable_size = true;
138  f->unmap_shadow_on_exit = false;
139  f->abort_on_error = false;
140  f->print_stats = false;
141  f->print_legend = true;
142  f->atexit = false;
143  f->disable_core = (SANITIZER_WORDSIZE == 64);
144  f->strip_path_prefix = "";
145  f->allow_reexec = true;
146  f->print_full_thread_history = true;
147  f->log_path = 0;
148  f->fast_unwind_on_fatal = false;
149  f->fast_unwind_on_malloc = true;
150  f->poison_heap = true;
151  // Turn off alloc/dealloc mismatch checker on Mac for now.
152  // TODO(glider): Fix known issues and enable this back.
153  f->alloc_dealloc_mismatch = (ASAN_MAC == 0);
154  f->use_stack_depot = true;  // Only affects allocator2.
155
156  // Override from user-specified string.
157  ParseFlagsFromString(f, MaybeCallAsanDefaultOptions());
158  if (flags()->verbosity) {
159    Report("Using the defaults from __asan_default_options: %s\n",
160           MaybeCallAsanDefaultOptions());
161  }
162
163  // Override from command line.
164  ParseFlagsFromString(f, env);
165}
166
167// -------------------------- Globals --------------------- {{{1
168int asan_inited;
169bool asan_init_is_running;
170void (*death_callback)(void);
171uptr kHighMemEnd;
172
173// -------------------------- Misc ---------------- {{{1
174void ShowStatsAndAbort() {
175  __asan_print_accumulated_stats();
176  Die();
177}
178
179// ---------------------- mmap -------------------- {{{1
180// Reserve memory range [beg, end].
181static void ReserveShadowMemoryRange(uptr beg, uptr end) {
182  CHECK((beg % GetPageSizeCached()) == 0);
183  CHECK(((end + 1) % GetPageSizeCached()) == 0);
184  uptr size = end - beg + 1;
185  void *res = MmapFixedNoReserve(beg, size);
186  if (res != (void*)beg) {
187    Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
188           "Perhaps you're using ulimit -v\n", size);
189    Abort();
190  }
191}
192
193// --------------- LowLevelAllocateCallbac ---------- {{{1
194static void OnLowLevelAllocate(uptr ptr, uptr size) {
195  PoisonShadow(ptr, size, kAsanInternalHeapMagic);
196}
197
198// -------------------------- Run-time entry ------------------- {{{1
199// exported functions
200#define ASAN_REPORT_ERROR(type, is_write, size)                     \
201extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
202void __asan_report_ ## type ## size(uptr addr);                \
203void __asan_report_ ## type ## size(uptr addr) {               \
204  GET_CALLER_PC_BP_SP;                                              \
205  __asan_report_error(pc, bp, sp, addr, is_write, size);            \
206}
207
208ASAN_REPORT_ERROR(load, false, 1)
209ASAN_REPORT_ERROR(load, false, 2)
210ASAN_REPORT_ERROR(load, false, 4)
211ASAN_REPORT_ERROR(load, false, 8)
212ASAN_REPORT_ERROR(load, false, 16)
213ASAN_REPORT_ERROR(store, true, 1)
214ASAN_REPORT_ERROR(store, true, 2)
215ASAN_REPORT_ERROR(store, true, 4)
216ASAN_REPORT_ERROR(store, true, 8)
217ASAN_REPORT_ERROR(store, true, 16)
218
219// Force the linker to keep the symbols for various ASan interface functions.
220// We want to keep those in the executable in order to let the instrumented
221// dynamic libraries access the symbol even if it is not used by the executable
222// itself. This should help if the build system is removing dead code at link
223// time.
224static NOINLINE void force_interface_symbols() {
225  volatile int fake_condition = 0;  // prevent dead condition elimination.
226  // __asan_report_* functions are noreturn, so we need a switch to prevent
227  // the compiler from removing any of them.
228  switch (fake_condition) {
229    case 1: __asan_report_load1(0); break;
230    case 2: __asan_report_load2(0); break;
231    case 3: __asan_report_load4(0); break;
232    case 4: __asan_report_load8(0); break;
233    case 5: __asan_report_load16(0); break;
234    case 6: __asan_report_store1(0); break;
235    case 7: __asan_report_store2(0); break;
236    case 8: __asan_report_store4(0); break;
237    case 9: __asan_report_store8(0); break;
238    case 10: __asan_report_store16(0); break;
239    case 12: __asan_register_globals(0, 0); break;
240    case 13: __asan_unregister_globals(0, 0); break;
241    case 14: __asan_set_death_callback(0); break;
242    case 15: __asan_set_error_report_callback(0); break;
243    case 16: __asan_handle_no_return(); break;
244    case 17: __asan_address_is_poisoned(0); break;
245    case 18: __asan_get_allocated_size(0); break;
246    case 19: __asan_get_current_allocated_bytes(); break;
247    case 20: __asan_get_estimated_allocated_size(0); break;
248    case 21: __asan_get_free_bytes(); break;
249    case 22: __asan_get_heap_size(); break;
250    case 23: __asan_get_ownership(0); break;
251    case 24: __asan_get_unmapped_bytes(); break;
252    case 25: __asan_poison_memory_region(0, 0); break;
253    case 26: __asan_unpoison_memory_region(0, 0); break;
254    case 27: __asan_set_error_exit_code(0); break;
255    case 28: __asan_stack_free(0, 0, 0); break;
256    case 29: __asan_stack_malloc(0, 0); break;
257    case 30: __asan_before_dynamic_init(0, 0); break;
258    case 31: __asan_after_dynamic_init(); break;
259    case 32: __asan_poison_stack_memory(0, 0); break;
260    case 33: __asan_unpoison_stack_memory(0, 0); break;
261    case 34: __asan_region_is_poisoned(0, 0); break;
262    case 35: __asan_describe_address(0); break;
263  }
264}
265
266static void asan_atexit() {
267  Printf("AddressSanitizer exit stats:\n");
268  __asan_print_accumulated_stats();
269}
270
271static void InitializeHighMemEnd() {
272#if SANITIZER_WORDSIZE == 64
273# if defined(__powerpc64__)
274  // FIXME:
275  // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
276  // We somehow need to figure our which one we are using now and choose
277  // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
278  // Note that with 'ulimit -s unlimited' the stack is moved away from the top
279  // of the address space, so simply checking the stack address is not enough.
280  kHighMemEnd = (1ULL << 44) - 1;  // 0x00000fffffffffffUL
281# else
282  kHighMemEnd = (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
283# endif
284#else  // SANITIZER_WORDSIZE == 32
285  kHighMemEnd = (1ULL << 32) - 1;  // 0xffffffff;
286#endif  // SANITIZER_WORDSIZE
287}
288
289}  // namespace __asan
290
291// ---------------------- Interface ---------------- {{{1
292using namespace __asan;  // NOLINT
293
294#if !SANITIZER_SUPPORTS_WEAK_HOOKS
295extern "C" {
296SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
297const char* __asan_default_options() { return ""; }
298}  // extern "C"
299#endif
300
301int NOINLINE __asan_set_error_exit_code(int exit_code) {
302  int old = flags()->exitcode;
303  flags()->exitcode = exit_code;
304  return old;
305}
306
307void NOINLINE __asan_handle_no_return() {
308  int local_stack;
309  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
310  CHECK(curr_thread);
311  uptr PageSize = GetPageSizeCached();
312  uptr top = curr_thread->stack_top();
313  uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
314  PoisonShadow(bottom, top - bottom, 0);
315}
316
317void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
318  death_callback = callback;
319}
320
321void __asan_init() {
322  if (asan_inited) return;
323  CHECK(!asan_init_is_running && "ASan init calls itself!");
324  asan_init_is_running = true;
325  InitializeHighMemEnd();
326
327  // Make sure we are not statically linked.
328  AsanDoesNotSupportStaticLinkage();
329
330  // Install tool-specific callbacks in sanitizer_common.
331  SetDieCallback(AsanDie);
332  SetCheckFailedCallback(AsanCheckFailed);
333  SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
334
335  // Initialize flags. This must be done early, because most of the
336  // initialization steps look at flags().
337  const char *options = GetEnv("ASAN_OPTIONS");
338  InitializeFlags(flags(), options);
339  __sanitizer_set_report_path(flags()->log_path);
340
341  if (flags()->verbosity && options) {
342    Report("Parsed ASAN_OPTIONS: %s\n", options);
343  }
344
345  // Re-exec ourselves if we need to set additional env or command line args.
346  MaybeReexec();
347
348  // Setup internal allocator callback.
349  SetLowLevelAllocateCallback(OnLowLevelAllocate);
350
351  if (flags()->atexit) {
352    Atexit(asan_atexit);
353  }
354
355  // interceptors
356  InitializeAsanInterceptors();
357
358  ReplaceSystemMalloc();
359  ReplaceOperatorsNewAndDelete();
360
361  if (flags()->verbosity) {
362    Printf("|| `[%p, %p]` || HighMem    ||\n",
363           (void*)kHighMemBeg, (void*)kHighMemEnd);
364    Printf("|| `[%p, %p]` || HighShadow ||\n",
365           (void*)kHighShadowBeg, (void*)kHighShadowEnd);
366    Printf("|| `[%p, %p]` || ShadowGap  ||\n",
367           (void*)kShadowGapBeg, (void*)kShadowGapEnd);
368    Printf("|| `[%p, %p]` || LowShadow  ||\n",
369           (void*)kLowShadowBeg, (void*)kLowShadowEnd);
370    Printf("|| `[%p, %p]` || LowMem     ||\n",
371           (void*)kLowMemBeg, (void*)kLowMemEnd);
372    Printf("MemToShadow(shadow): %p %p %p %p\n",
373           (void*)MEM_TO_SHADOW(kLowShadowBeg),
374           (void*)MEM_TO_SHADOW(kLowShadowEnd),
375           (void*)MEM_TO_SHADOW(kHighShadowBeg),
376           (void*)MEM_TO_SHADOW(kHighShadowEnd));
377    Printf("red_zone=%zu\n", (uptr)flags()->redzone);
378    Printf("malloc_context_size=%zu\n", (uptr)flags()->malloc_context_size);
379
380    Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
381    Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
382    Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
383    CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
384  }
385
386  if (flags()->disable_core) {
387    DisableCoreDumper();
388  }
389
390  uptr shadow_start = kLowShadowBeg;
391  if (kLowShadowBeg > 0) shadow_start -= GetMmapGranularity();
392  uptr shadow_end = kHighShadowEnd;
393  if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
394    if (kLowShadowBeg != kLowShadowEnd) {
395      // mmap the low shadow plus at least one page.
396      ReserveShadowMemoryRange(kLowShadowBeg - GetMmapGranularity(),
397                               kLowShadowEnd);
398    }
399    // mmap the high shadow.
400    ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
401    // protect the gap
402    void *prot = Mprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
403    CHECK(prot == (void*)kShadowGapBeg);
404  } else {
405    Report("Shadow memory range interleaves with an existing memory mapping. "
406           "ASan cannot proceed correctly. ABORTING.\n");
407    DumpProcessMap();
408    Die();
409  }
410
411  InstallSignalHandlers();
412  // Start symbolizer process if necessary.
413  if (flags()->symbolize) {
414    const char *external_symbolizer = GetEnv("ASAN_SYMBOLIZER_PATH");
415    if (external_symbolizer) {
416      InitializeExternalSymbolizer(external_symbolizer);
417    }
418  }
419
420  // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
421  // should be set to 1 prior to initializing the threads.
422  asan_inited = 1;
423  asan_init_is_running = false;
424
425  asanThreadRegistry().Init();
426  asanThreadRegistry().GetMain()->ThreadStart();
427  force_interface_symbols();  // no-op.
428
429  if (flags()->verbosity) {
430    Report("AddressSanitizer Init done\n");
431  }
432}
433
434#if defined(ASAN_USE_PREINIT_ARRAY)
435  // On Linux, we force __asan_init to be called before anyone else
436  // by placing it into .preinit_array section.
437  // FIXME: do we have anything like this on Mac?
438  __attribute__((section(".preinit_array")))
439    typeof(__asan_init) *__asan_preinit =__asan_init;
440#elif defined(_WIN32) && defined(_DLL)
441  // On Windows, when using dynamic CRT (/MD), we can put a pointer
442  // to __asan_init into the global list of C initializers.
443  // See crt0dat.c in the CRT sources for the details.
444  #pragma section(".CRT$XIB", long, read)  // NOLINT
445  __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
446#endif
447