asan_rtl.cc revision 8e23d275ec871c16b71f3a98cc475f0db8cb3863 
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 __sanitizer {
31using namespace __asan;
32
33void Die() {
34  static atomic_uint32_t num_calls;
35  if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
36    // Don't die twice - run a busy loop.
37    while (1) { }
38  }
39  if (flags()->sleep_before_dying) {
40    Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
41    SleepForSeconds(flags()->sleep_before_dying);
42  }
43  if (flags()->unmap_shadow_on_exit)
44    UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
45  if (death_callback)
46    death_callback();
47  if (flags()->abort_on_error)
48    Abort();
49  Exit(flags()->exitcode);
50}
51
52SANITIZER_INTERFACE_ATTRIBUTE
53void CheckFailed(const char *file, int line, const char *cond, u64 v1, u64 v2) {
54  Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
55             file, line, cond, (uptr)v1, (uptr)v2);
56  // FIXME: check for infinite recursion without a thread-local counter here.
57  PRINT_CURRENT_STACK();
58  ShowStatsAndAbort();
59}
60
61}  // namespace __sanitizer
62
63namespace __asan {
64
65// -------------------------- Flags ------------------------- {{{1
66static const int kDeafultMallocContextSize = 30;
67
68static Flags asan_flags;
69
70Flags *flags() {
71  return &asan_flags;
72}
73
74static void ParseFlagsFromString(Flags *f, const char *str) {
75  ParseFlag(str, &f->quarantine_size, "quarantine_size");
76  ParseFlag(str, &f->symbolize, "symbolize");
77  ParseFlag(str, &f->verbosity, "verbosity");
78  ParseFlag(str, &f->redzone, "redzone");
79  CHECK(f->redzone >= 16);
80  CHECK(IsPowerOfTwo(f->redzone));
81
82  ParseFlag(str, &f->debug, "debug");
83  ParseFlag(str, &f->report_globals, "report_globals");
84  ParseFlag(str, &f->check_initialization_order, "initialization_order");
85  ParseFlag(str, &f->malloc_context_size, "malloc_context_size");
86  CHECK((uptr)f->malloc_context_size <= kStackTraceMax);
87
88  ParseFlag(str, &f->replace_str, "replace_str");
89  ParseFlag(str, &f->replace_intrin, "replace_intrin");
90  ParseFlag(str, &f->replace_cfallocator, "replace_cfallocator");
91  ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
92  ParseFlag(str, &f->use_fake_stack, "use_fake_stack");
93  ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
94  ParseFlag(str, &f->exitcode, "exitcode");
95  ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
96  ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
97  ParseFlag(str, &f->handle_segv, "handle_segv");
98  ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
99  ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
100  ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
101  ParseFlag(str, &f->abort_on_error, "abort_on_error");
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}
108
109extern "C" {
110SANITIZER_WEAK_ATTRIBUTE
111SANITIZER_INTERFACE_ATTRIBUTE
112const char* __asan_default_options() { return ""; }
113}  // extern "C"
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_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->atexit = false;
141  f->disable_core = (__WORDSIZE == 64);
142  f->strip_path_prefix = "";
143  f->allow_reexec = true;
144  f->print_full_thread_history = true;
145
146  // Override from user-specified string.
147  ParseFlagsFromString(f, __asan_default_options());
148  if (flags()->verbosity) {
149    Report("Using the defaults from __asan_default_options: %s\n",
150           __asan_default_options());
151  }
152
153  // Override from command line.
154  ParseFlagsFromString(f, env);
155}
156
157// -------------------------- Globals --------------------- {{{1
158int asan_inited;
159bool asan_init_is_running;
160void (*death_callback)(void);
161
162// -------------------------- Misc ---------------- {{{1
163void ShowStatsAndAbort() {
164  __asan_print_accumulated_stats();
165  Die();
166}
167
168// ---------------------- mmap -------------------- {{{1
169// Reserve memory range [beg, end].
170static void ReserveShadowMemoryRange(uptr beg, uptr end) {
171  CHECK((beg % kPageSize) == 0);
172  CHECK(((end + 1) % kPageSize) == 0);
173  uptr size = end - beg + 1;
174  void *res = MmapFixedNoReserve(beg, size);
175  if (res != (void*)beg) {
176    Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
177           "Perhaps you're using ulimit -v\n", size);
178    Abort();
179  }
180}
181
182// --------------- LowLevelAllocateCallbac ---------- {{{1
183static void OnLowLevelAllocate(uptr ptr, uptr size) {
184  PoisonShadow(ptr, size, kAsanInternalHeapMagic);
185}
186
187// -------------------------- Run-time entry ------------------- {{{1
188// exported functions
189#define ASAN_REPORT_ERROR(type, is_write, size)                     \
190extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
191void __asan_report_ ## type ## size(uptr addr);                \
192void __asan_report_ ## type ## size(uptr addr) {               \
193  GET_CALLER_PC_BP_SP;                                              \
194  __asan_report_error(pc, bp, sp, addr, is_write, size);            \
195}
196
197ASAN_REPORT_ERROR(load, false, 1)
198ASAN_REPORT_ERROR(load, false, 2)
199ASAN_REPORT_ERROR(load, false, 4)
200ASAN_REPORT_ERROR(load, false, 8)
201ASAN_REPORT_ERROR(load, false, 16)
202ASAN_REPORT_ERROR(store, true, 1)
203ASAN_REPORT_ERROR(store, true, 2)
204ASAN_REPORT_ERROR(store, true, 4)
205ASAN_REPORT_ERROR(store, true, 8)
206ASAN_REPORT_ERROR(store, true, 16)
207
208// Force the linker to keep the symbols for various ASan interface functions.
209// We want to keep those in the executable in order to let the instrumented
210// dynamic libraries access the symbol even if it is not used by the executable
211// itself. This should help if the build system is removing dead code at link
212// time.
213static NOINLINE void force_interface_symbols() {
214  volatile int fake_condition = 0;  // prevent dead condition elimination.
215  // __asan_report_* functions are noreturn, so we need a switch to prevent
216  // the compiler from removing any of them.
217  switch (fake_condition) {
218    case 1: __asan_report_load1(0); break;
219    case 2: __asan_report_load2(0); break;
220    case 3: __asan_report_load4(0); break;
221    case 4: __asan_report_load8(0); break;
222    case 5: __asan_report_load16(0); break;
223    case 6: __asan_report_store1(0); break;
224    case 7: __asan_report_store2(0); break;
225    case 8: __asan_report_store4(0); break;
226    case 9: __asan_report_store8(0); break;
227    case 10: __asan_report_store16(0); break;
228    case 11: __asan_register_global(0, 0, 0); break;
229    case 12: __asan_register_globals(0, 0); break;
230    case 13: __asan_unregister_globals(0, 0); break;
231    case 14: __asan_set_death_callback(0); break;
232    case 15: __asan_set_error_report_callback(0); break;
233    case 16: __asan_handle_no_return(); break;
234    case 17: __asan_address_is_poisoned(0); break;
235    case 18: __asan_get_allocated_size(0); break;
236    case 19: __asan_get_current_allocated_bytes(); break;
237    case 20: __asan_get_estimated_allocated_size(0); break;
238    case 21: __asan_get_free_bytes(); break;
239    case 22: __asan_get_heap_size(); break;
240    case 23: __asan_get_ownership(0); break;
241    case 24: __asan_get_unmapped_bytes(); break;
242    case 25: __asan_poison_memory_region(0, 0); break;
243    case 26: __asan_unpoison_memory_region(0, 0); break;
244    case 27: __asan_set_error_exit_code(0); break;
245    case 28: __asan_stack_free(0, 0, 0); break;
246    case 29: __asan_stack_malloc(0, 0); break;
247    case 30: __asan_set_on_error_callback(0); break;
248    case 31: __asan_default_options(); break;
249    case 32: __asan_before_dynamic_init(0, 0); break;
250    case 33: __asan_after_dynamic_init(); break;
251    case 34: __asan_malloc_hook(0, 0); break;
252    case 35: __asan_free_hook(0); break;
253    case 36: __asan_set_symbolize_callback(0); break;
254  }
255}
256
257static void asan_atexit() {
258  Printf("AddressSanitizer exit stats:\n");
259  __asan_print_accumulated_stats();
260}
261
262}  // namespace __asan
263
264// ---------------------- Interface ---------------- {{{1
265using namespace __asan;  // NOLINT
266
267int NOINLINE __asan_set_error_exit_code(int exit_code) {
268  int old = flags()->exitcode;
269  flags()->exitcode = exit_code;
270  return old;
271}
272
273void NOINLINE __asan_handle_no_return() {
274  int local_stack;
275  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
276  CHECK(curr_thread);
277  uptr top = curr_thread->stack_top();
278  uptr bottom = ((uptr)&local_stack - kPageSize) & ~(kPageSize-1);
279  PoisonShadow(bottom, top - bottom, 0);
280}
281
282void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
283  death_callback = callback;
284}
285
286void __asan_init() {
287  if (asan_inited) return;
288  CHECK(!asan_init_is_running && "ASan init calls itself!");
289  asan_init_is_running = true;
290
291  // Make sure we are not statically linked.
292  AsanDoesNotSupportStaticLinkage();
293
294  SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
295
296  // Initialize flags. This must be done early, because most of the
297  // initialization steps look at flags().
298  const char *options = GetEnv("ASAN_OPTIONS");
299  InitializeFlags(flags(), options);
300
301  if (flags()->verbosity && options) {
302    Report("Parsed ASAN_OPTIONS: %s\n", options);
303  }
304
305  // Re-exec ourselves if we need to set additional env or command line args.
306  MaybeReexec();
307
308  // Setup internal allocator callback.
309  SetLowLevelAllocateCallback(OnLowLevelAllocate);
310
311  if (flags()->atexit) {
312    Atexit(asan_atexit);
313  }
314
315  // interceptors
316  InitializeAsanInterceptors();
317
318  ReplaceSystemMalloc();
319  ReplaceOperatorsNewAndDelete();
320
321  if (flags()->verbosity) {
322    Printf("|| `[%p, %p]` || HighMem    ||\n",
323           (void*)kHighMemBeg, (void*)kHighMemEnd);
324    Printf("|| `[%p, %p]` || HighShadow ||\n",
325           (void*)kHighShadowBeg, (void*)kHighShadowEnd);
326    Printf("|| `[%p, %p]` || ShadowGap  ||\n",
327           (void*)kShadowGapBeg, (void*)kShadowGapEnd);
328    Printf("|| `[%p, %p]` || LowShadow  ||\n",
329           (void*)kLowShadowBeg, (void*)kLowShadowEnd);
330    Printf("|| `[%p, %p]` || LowMem     ||\n",
331           (void*)kLowMemBeg, (void*)kLowMemEnd);
332    Printf("MemToShadow(shadow): %p %p %p %p\n",
333           (void*)MEM_TO_SHADOW(kLowShadowBeg),
334           (void*)MEM_TO_SHADOW(kLowShadowEnd),
335           (void*)MEM_TO_SHADOW(kHighShadowBeg),
336           (void*)MEM_TO_SHADOW(kHighShadowEnd));
337    Printf("red_zone=%zu\n", (uptr)flags()->redzone);
338    Printf("malloc_context_size=%zu\n", (uptr)flags()->malloc_context_size);
339
340    Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
341    Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
342    Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
343    CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
344  }
345
346  if (flags()->disable_core) {
347    DisableCoreDumper();
348  }
349
350  uptr shadow_start = kLowShadowBeg;
351  if (kLowShadowBeg > 0) shadow_start -= kMmapGranularity;
352  uptr shadow_end = kHighShadowEnd;
353  if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
354    if (kLowShadowBeg != kLowShadowEnd) {
355      // mmap the low shadow plus at least one page.
356      ReserveShadowMemoryRange(kLowShadowBeg - kMmapGranularity, kLowShadowEnd);
357    }
358    // mmap the high shadow.
359    ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
360    // protect the gap
361    void *prot = Mprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
362    CHECK(prot == (void*)kShadowGapBeg);
363  } else {
364    Report("Shadow memory range interleaves with an existing memory mapping. "
365           "ASan cannot proceed correctly. ABORTING.\n");
366    DumpProcessMap();
367    Die();
368  }
369
370  InstallSignalHandlers();
371  // Start symbolizer process if necessary.
372  if (flags()->symbolize) {
373    const char *external_symbolizer = GetEnv("ASAN_SYMBOLIZER_PATH");
374    if (external_symbolizer) {
375      InitializeExternalSymbolizer(external_symbolizer);
376    }
377  }
378#ifdef _WIN32
379  __asan_set_symbolize_callback(WinSymbolize);
380#endif  // _WIN32
381
382  // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
383  // should be set to 1 prior to initializing the threads.
384  asan_inited = 1;
385  asan_init_is_running = false;
386
387  asanThreadRegistry().Init();
388  asanThreadRegistry().GetMain()->ThreadStart();
389  force_interface_symbols();  // no-op.
390
391  if (flags()->verbosity) {
392    Report("AddressSanitizer Init done\n");
393  }
394}
395
396#if defined(ASAN_USE_PREINIT_ARRAY)
397  // On Linux, we force __asan_init to be called before anyone else
398  // by placing it into .preinit_array section.
399  // FIXME: do we have anything like this on Mac?
400  __attribute__((section(".preinit_array")))
401    typeof(__asan_init) *__asan_preinit =__asan_init;
402#elif defined(_WIN32) && defined(_DLL)
403  // On Windows, when using dynamic CRT (/MD), we can put a pointer
404  // to __asan_init into the global list of C initializers.
405  // See crt0dat.c in the CRT sources for the details.
406  #pragma section(".CRT$XIB", long, read)  // NOLINT
407  __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
408#endif
409