asan_rtl.cc revision 73bad81febb2a872627c03e579beea1da4b49294 
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_lock.h"
18#include "asan_mapping.h"
19#include "asan_report.h"
20#include "asan_stack.h"
21#include "asan_stats.h"
22#include "asan_thread.h"
23#include "asan_thread_registry.h"
24#include "sanitizer/asan_interface.h"
25#include "sanitizer_common/sanitizer_atomic.h"
26#include "sanitizer_common/sanitizer_flags.h"
27#include "sanitizer_common/sanitizer_libc.h"
28#include "sanitizer_common/sanitizer_symbolizer.h"
29
30namespace __asan {
31
32static void AsanDie() {
33  static atomic_uint32_t num_calls;
34  if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
35    // Don't die twice - run a busy loop.
36    while (1) { }
37  }
38  if (flags()->sleep_before_dying) {
39    Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
40    SleepForSeconds(flags()->sleep_before_dying);
41  }
42  if (flags()->unmap_shadow_on_exit)
43    UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
44  if (death_callback)
45    death_callback();
46  if (flags()->abort_on_error)
47    Abort();
48  Exit(flags()->exitcode);
49}
50
51static void AsanCheckFailed(const char *file, int line, const char *cond,
52                            u64 v1, u64 v2) {
53  Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
54             file, line, cond, (uptr)v1, (uptr)v2);
55  // FIXME: check for infinite recursion without a thread-local counter here.
56  PRINT_CURRENT_STACK();
57  Die();
58}
59
60// -------------------------- Flags ------------------------- {{{1
61static const int kDeafultMallocContextSize = 30;
62
63static Flags asan_flags;
64
65Flags *flags() {
66  return &asan_flags;
67}
68
69static const char *MaybeCallAsanDefaultOptions() {
70  return (&__asan_default_options) ? __asan_default_options() : "";
71}
72
73static void ParseFlagsFromString(Flags *f, const char *str) {
74  ParseFlag(str, &f->quarantine_size, "quarantine_size");
75  ParseFlag(str, &f->symbolize, "symbolize");
76  ParseFlag(str, &f->verbosity, "verbosity");
77  ParseFlag(str, &f->redzone, "redzone");
78  CHECK(f->redzone >= 16);
79  CHECK(IsPowerOfTwo(f->redzone));
80
81  ParseFlag(str, &f->debug, "debug");
82  ParseFlag(str, &f->report_globals, "report_globals");
83  ParseFlag(str, &f->check_initialization_order, "initialization_order");
84  ParseFlag(str, &f->malloc_context_size, "malloc_context_size");
85  CHECK((uptr)f->malloc_context_size <= kStackTraceMax);
86
87  ParseFlag(str, &f->replace_str, "replace_str");
88  ParseFlag(str, &f->replace_intrin, "replace_intrin");
89  ParseFlag(str, &f->replace_cfallocator, "replace_cfallocator");
90  ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
91  ParseFlag(str, &f->use_fake_stack, "use_fake_stack");
92  ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
93  ParseFlag(str, &f->exitcode, "exitcode");
94  ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
95  ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
96  ParseFlag(str, &f->handle_segv, "handle_segv");
97  ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
98  ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
99  ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
100  ParseFlag(str, &f->abort_on_error, "abort_on_error");
101  ParseFlag(str, &f->atexit, "atexit");
102  ParseFlag(str, &f->disable_core, "disable_core");
103  ParseFlag(str, &f->strip_path_prefix, "strip_path_prefix");
104  ParseFlag(str, &f->allow_reexec, "allow_reexec");
105  ParseFlag(str, &f->print_full_thread_history, "print_full_thread_history");
106  ParseFlag(str, &f->log_path, "log_path");
107  ParseFlag(str, &f->fast_unwind_on_fatal, "fast_unwind_on_fatal");
108  ParseFlag(str, &f->fast_unwind_on_malloc, "fast_unwind_on_malloc");
109  ParseFlag(str, &f->poison_heap, "poison_heap");
110}
111
112void InitializeFlags(Flags *f, const char *env) {
113  internal_memset(f, 0, sizeof(*f));
114
115  f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
116  f->symbolize = false;
117  f->verbosity = 0;
118  f->redzone = (ASAN_LOW_MEMORY) ? 64 : 128;
119  f->debug = false;
120  f->report_globals = 1;
121  f->check_initialization_order = true;
122  f->malloc_context_size = kDeafultMallocContextSize;
123  f->replace_str = true;
124  f->replace_intrin = true;
125  f->replace_cfallocator = true;
126  f->mac_ignore_invalid_free = false;
127  f->use_fake_stack = true;
128  f->max_malloc_fill_size = 0;
129  f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
130  f->allow_user_poisoning = true;
131  f->sleep_before_dying = 0;
132  f->handle_segv = ASAN_NEEDS_SEGV;
133  f->use_sigaltstack = false;
134  f->check_malloc_usable_size = true;
135  f->unmap_shadow_on_exit = false;
136  f->abort_on_error = false;
137  f->atexit = false;
138  f->disable_core = (SANITIZER_WORDSIZE == 64);
139  f->strip_path_prefix = "";
140  f->allow_reexec = true;
141  f->print_full_thread_history = true;
142  f->log_path = 0;
143  f->fast_unwind_on_fatal = true;
144  f->fast_unwind_on_malloc = true;
145  f->poison_heap = true;
146
147  // Override from user-specified string.
148  ParseFlagsFromString(f, MaybeCallAsanDefaultOptions());
149  if (flags()->verbosity) {
150    Report("Using the defaults from __asan_default_options: %s\n",
151           MaybeCallAsanDefaultOptions());
152  }
153
154  // Override from command line.
155  ParseFlagsFromString(f, env);
156}
157
158// -------------------------- Globals --------------------- {{{1
159int asan_inited;
160bool asan_init_is_running;
161void (*death_callback)(void);
162
163// -------------------------- Misc ---------------- {{{1
164void ShowStatsAndAbort() {
165  __asan_print_accumulated_stats();
166  Die();
167}
168
169// ---------------------- mmap -------------------- {{{1
170// Reserve memory range [beg, end].
171static void ReserveShadowMemoryRange(uptr beg, uptr end) {
172  CHECK((beg % GetPageSizeCached()) == 0);
173  CHECK(((end + 1) % GetPageSizeCached()) == 0);
174  uptr size = end - beg + 1;
175  void *res = MmapFixedNoReserve(beg, size);
176  if (res != (void*)beg) {
177    Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
178           "Perhaps you're using ulimit -v\n", size);
179    Abort();
180  }
181}
182
183// --------------- LowLevelAllocateCallbac ---------- {{{1
184static void OnLowLevelAllocate(uptr ptr, uptr size) {
185  PoisonShadow(ptr, size, kAsanInternalHeapMagic);
186}
187
188// -------------------------- Run-time entry ------------------- {{{1
189// exported functions
190#define ASAN_REPORT_ERROR(type, is_write, size)                     \
191extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
192void __asan_report_ ## type ## size(uptr addr);                \
193void __asan_report_ ## type ## size(uptr addr) {               \
194  GET_CALLER_PC_BP_SP;                                              \
195  __asan_report_error(pc, bp, sp, addr, is_write, size);            \
196}
197
198ASAN_REPORT_ERROR(load, false, 1)
199ASAN_REPORT_ERROR(load, false, 2)
200ASAN_REPORT_ERROR(load, false, 4)
201ASAN_REPORT_ERROR(load, false, 8)
202ASAN_REPORT_ERROR(load, false, 16)
203ASAN_REPORT_ERROR(store, true, 1)
204ASAN_REPORT_ERROR(store, true, 2)
205ASAN_REPORT_ERROR(store, true, 4)
206ASAN_REPORT_ERROR(store, true, 8)
207ASAN_REPORT_ERROR(store, true, 16)
208
209// Force the linker to keep the symbols for various ASan interface functions.
210// We want to keep those in the executable in order to let the instrumented
211// dynamic libraries access the symbol even if it is not used by the executable
212// itself. This should help if the build system is removing dead code at link
213// time.
214static NOINLINE void force_interface_symbols() {
215  volatile int fake_condition = 0;  // prevent dead condition elimination.
216  // __asan_report_* functions are noreturn, so we need a switch to prevent
217  // the compiler from removing any of them.
218  switch (fake_condition) {
219    case 1: __asan_report_load1(0); break;
220    case 2: __asan_report_load2(0); break;
221    case 3: __asan_report_load4(0); break;
222    case 4: __asan_report_load8(0); break;
223    case 5: __asan_report_load16(0); break;
224    case 6: __asan_report_store1(0); break;
225    case 7: __asan_report_store2(0); break;
226    case 8: __asan_report_store4(0); break;
227    case 9: __asan_report_store8(0); break;
228    case 10: __asan_report_store16(0); break;
229    case 11: __asan_register_global(0, 0, 0); break;
230    case 12: __asan_register_globals(0, 0); break;
231    case 13: __asan_unregister_globals(0, 0); break;
232    case 14: __asan_set_death_callback(0); break;
233    case 15: __asan_set_error_report_callback(0); break;
234    case 16: __asan_handle_no_return(); break;
235    case 17: __asan_address_is_poisoned(0); break;
236    case 18: __asan_get_allocated_size(0); break;
237    case 19: __asan_get_current_allocated_bytes(); break;
238    case 20: __asan_get_estimated_allocated_size(0); break;
239    case 21: __asan_get_free_bytes(); break;
240    case 22: __asan_get_heap_size(); break;
241    case 23: __asan_get_ownership(0); break;
242    case 24: __asan_get_unmapped_bytes(); break;
243    case 25: __asan_poison_memory_region(0, 0); break;
244    case 26: __asan_unpoison_memory_region(0, 0); break;
245    case 27: __asan_set_error_exit_code(0); break;
246    case 28: __asan_stack_free(0, 0, 0); break;
247    case 29: __asan_stack_malloc(0, 0); break;
248    case 30: __asan_before_dynamic_init(0, 0); break;
249    case 31: __asan_after_dynamic_init(); break;
250    case 32: __asan_poison_stack_memory(0, 0); break;
251    case 33: __asan_unpoison_stack_memory(0, 0); break;
252  }
253}
254
255static void asan_atexit() {
256  Printf("AddressSanitizer exit stats:\n");
257  __asan_print_accumulated_stats();
258}
259
260}  // namespace __asan
261
262// ---------------------- Interface ---------------- {{{1
263using namespace __asan;  // NOLINT
264
265#if !SANITIZER_SUPPORTS_WEAK_HOOKS
266extern "C" {
267SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
268const char* __asan_default_options() { return ""; }
269}  // extern "C"
270#endif
271
272int NOINLINE __asan_set_error_exit_code(int exit_code) {
273  int old = flags()->exitcode;
274  flags()->exitcode = exit_code;
275  return old;
276}
277
278void NOINLINE __asan_handle_no_return() {
279  int local_stack;
280  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
281  CHECK(curr_thread);
282  uptr PageSize = GetPageSizeCached();
283  uptr top = curr_thread->stack_top();
284  uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
285  PoisonShadow(bottom, top - bottom, 0);
286}
287
288void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
289  death_callback = callback;
290}
291
292void __asan_init() {
293  if (asan_inited) return;
294  CHECK(!asan_init_is_running && "ASan init calls itself!");
295  asan_init_is_running = true;
296
297  // Make sure we are not statically linked.
298  AsanDoesNotSupportStaticLinkage();
299
300  // Install tool-specific callbacks in sanitizer_common.
301  SetDieCallback(AsanDie);
302  SetCheckFailedCallback(AsanCheckFailed);
303  SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
304
305  // Initialize flags. This must be done early, because most of the
306  // initialization steps look at flags().
307  const char *options = GetEnv("ASAN_OPTIONS");
308  InitializeFlags(flags(), options);
309  __sanitizer_set_report_path(flags()->log_path);
310
311  if (flags()->verbosity && options) {
312    Report("Parsed ASAN_OPTIONS: %s\n", options);
313  }
314
315  // Re-exec ourselves if we need to set additional env or command line args.
316  MaybeReexec();
317
318  // Setup internal allocator callback.
319  SetLowLevelAllocateCallback(OnLowLevelAllocate);
320
321  if (flags()->atexit) {
322    Atexit(asan_atexit);
323  }
324
325  // interceptors
326  InitializeAsanInterceptors();
327
328  ReplaceSystemMalloc();
329  ReplaceOperatorsNewAndDelete();
330
331  if (flags()->verbosity) {
332    Printf("|| `[%p, %p]` || HighMem    ||\n",
333           (void*)kHighMemBeg, (void*)kHighMemEnd);
334    Printf("|| `[%p, %p]` || HighShadow ||\n",
335           (void*)kHighShadowBeg, (void*)kHighShadowEnd);
336    Printf("|| `[%p, %p]` || ShadowGap  ||\n",
337           (void*)kShadowGapBeg, (void*)kShadowGapEnd);
338    Printf("|| `[%p, %p]` || LowShadow  ||\n",
339           (void*)kLowShadowBeg, (void*)kLowShadowEnd);
340    Printf("|| `[%p, %p]` || LowMem     ||\n",
341           (void*)kLowMemBeg, (void*)kLowMemEnd);
342    Printf("MemToShadow(shadow): %p %p %p %p\n",
343           (void*)MEM_TO_SHADOW(kLowShadowBeg),
344           (void*)MEM_TO_SHADOW(kLowShadowEnd),
345           (void*)MEM_TO_SHADOW(kHighShadowBeg),
346           (void*)MEM_TO_SHADOW(kHighShadowEnd));
347    Printf("red_zone=%zu\n", (uptr)flags()->redzone);
348    Printf("malloc_context_size=%zu\n", (uptr)flags()->malloc_context_size);
349
350    Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
351    Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
352    Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
353    CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
354  }
355
356  if (flags()->disable_core) {
357    DisableCoreDumper();
358  }
359
360  uptr shadow_start = kLowShadowBeg;
361  if (kLowShadowBeg > 0) shadow_start -= GetMmapGranularity();
362  uptr shadow_end = kHighShadowEnd;
363  if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
364    if (kLowShadowBeg != kLowShadowEnd) {
365      // mmap the low shadow plus at least one page.
366      ReserveShadowMemoryRange(kLowShadowBeg - GetMmapGranularity(),
367                               kLowShadowEnd);
368    }
369    // mmap the high shadow.
370    ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
371    // protect the gap
372    void *prot = Mprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
373    CHECK(prot == (void*)kShadowGapBeg);
374  } else {
375    Report("Shadow memory range interleaves with an existing memory mapping. "
376           "ASan cannot proceed correctly. ABORTING.\n");
377    DumpProcessMap();
378    Die();
379  }
380
381  InstallSignalHandlers();
382  // Start symbolizer process if necessary.
383  if (flags()->symbolize) {
384    const char *external_symbolizer = GetEnv("ASAN_SYMBOLIZER_PATH");
385    if (external_symbolizer) {
386      InitializeExternalSymbolizer(external_symbolizer);
387    }
388  }
389
390  // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
391  // should be set to 1 prior to initializing the threads.
392  asan_inited = 1;
393  asan_init_is_running = false;
394
395  asanThreadRegistry().Init();
396  asanThreadRegistry().GetMain()->ThreadStart();
397  force_interface_symbols();  // no-op.
398
399  if (flags()->verbosity) {
400    Report("AddressSanitizer Init done\n");
401  }
402}
403
404#if defined(ASAN_USE_PREINIT_ARRAY)
405  // On Linux, we force __asan_init to be called before anyone else
406  // by placing it into .preinit_array section.
407  // FIXME: do we have anything like this on Mac?
408  __attribute__((section(".preinit_array")))
409    typeof(__asan_init) *__asan_preinit =__asan_init;
410#elif defined(_WIN32) && defined(_DLL)
411  // On Windows, when using dynamic CRT (/MD), we can put a pointer
412  // to __asan_init into the global list of C initializers.
413  // See crt0dat.c in the CRT sources for the details.
414  #pragma section(".CRT$XIB", long, read)  // NOLINT
415  __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
416#endif
417