asan_rtl.cc revision 947fbd1a073fcd38988c1ec131452e99bb0313f8 
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_interface.h"
17#include "asan_internal.h"
18#include "asan_lock.h"
19#include "asan_mapping.h"
20#include "asan_report.h"
21#include "asan_stack.h"
22#include "asan_stats.h"
23#include "asan_thread.h"
24#include "asan_thread_registry.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  AsanReport("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
55             file, line, cond, (uptr)v1, (uptr)v2);
56  PRINT_CURRENT_STACK();
57  ShowStatsAndAbort();
58}
59
60}  // namespace __sanitizer
61
62namespace __asan {
63
64// -------------------------- Flags ------------------------- {{{1
65static const int kMallocContextSize = 30;
66
67static Flags asan_flags;
68
69Flags *flags() {
70  return &asan_flags;
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(f->malloc_context_size <= kMallocContextSize);
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}
106
107extern "C" {
108SANITIZER_WEAK_ATTRIBUTE
109SANITIZER_INTERFACE_ATTRIBUTE
110const char* __asan_default_options() { return ""; }
111}  // extern "C"
112
113void InitializeFlags(Flags *f, const char *env) {
114  internal_memset(f, 0, sizeof(*f));
115
116  f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 24 : 1UL << 28;
117  f->symbolize = false;
118  f->verbosity = 0;
119  f->redzone = (ASAN_LOW_MEMORY) ? 64 : 128;
120  f->debug = false;
121  f->report_globals = 1;
122  f->check_initialization_order = true;
123  f->malloc_context_size = kMallocContextSize;
124  f->replace_str = true;
125  f->replace_intrin = true;
126  f->replace_cfallocator = true;
127  f->mac_ignore_invalid_free = false;
128  f->use_fake_stack = true;
129  f->max_malloc_fill_size = 0;
130  f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
131  f->allow_user_poisoning = true;
132  f->sleep_before_dying = 0;
133  f->handle_segv = ASAN_NEEDS_SEGV;
134  f->use_sigaltstack = false;
135  f->check_malloc_usable_size = true;
136  f->unmap_shadow_on_exit = false;
137  f->abort_on_error = false;
138  f->atexit = false;
139  f->disable_core = (__WORDSIZE == 64);
140  f->strip_path_prefix = "";
141  f->allow_reexec = true;
142
143  // Override from user-specified string.
144  ParseFlagsFromString(f, __asan_default_options());
145  if (flags()->verbosity) {
146    Report("Using the defaults from __asan_default_options: %s\n",
147           __asan_default_options());
148  }
149
150  // Override from command line.
151  ParseFlagsFromString(f, env);
152}
153
154// -------------------------- Globals --------------------- {{{1
155int asan_inited;
156bool asan_init_is_running;
157void (*death_callback)(void);
158
159// -------------------------- Misc ---------------- {{{1
160void ShowStatsAndAbort() {
161  __asan_print_accumulated_stats();
162  Die();
163}
164
165// ---------------------- mmap -------------------- {{{1
166// Reserve memory range [beg, end].
167static void ReserveShadowMemoryRange(uptr beg, uptr end) {
168  CHECK((beg % kPageSize) == 0);
169  CHECK(((end + 1) % kPageSize) == 0);
170  uptr size = end - beg + 1;
171  void *res = MmapFixedNoReserve(beg, size);
172  CHECK(res == (void*)beg && "ReserveShadowMemoryRange failed");
173}
174
175// --------------- LowLevelAllocateCallbac ---------- {{{1
176static void OnLowLevelAllocate(uptr ptr, uptr size) {
177  PoisonShadow(ptr, size, kAsanInternalHeapMagic);
178}
179
180// -------------------------- Run-time entry ------------------- {{{1
181// exported functions
182#define ASAN_REPORT_ERROR(type, is_write, size)                     \
183extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
184void __asan_report_ ## type ## size(uptr addr);                \
185void __asan_report_ ## type ## size(uptr addr) {               \
186  GET_CALLER_PC_BP_SP;                                              \
187  __asan_report_error(pc, bp, sp, addr, is_write, size);            \
188}
189
190ASAN_REPORT_ERROR(load, false, 1)
191ASAN_REPORT_ERROR(load, false, 2)
192ASAN_REPORT_ERROR(load, false, 4)
193ASAN_REPORT_ERROR(load, false, 8)
194ASAN_REPORT_ERROR(load, false, 16)
195ASAN_REPORT_ERROR(store, true, 1)
196ASAN_REPORT_ERROR(store, true, 2)
197ASAN_REPORT_ERROR(store, true, 4)
198ASAN_REPORT_ERROR(store, true, 8)
199ASAN_REPORT_ERROR(store, true, 16)
200
201// Force the linker to keep the symbols for various ASan interface functions.
202// We want to keep those in the executable in order to let the instrumented
203// dynamic libraries access the symbol even if it is not used by the executable
204// itself. This should help if the build system is removing dead code at link
205// time.
206static NOINLINE void force_interface_symbols() {
207  volatile int fake_condition = 0;  // prevent dead condition elimination.
208  // __asan_report_* functions are noreturn, so we need a switch to prevent
209  // the compiler from removing any of them.
210  switch (fake_condition) {
211    case 1: __asan_report_load1(0); break;
212    case 2: __asan_report_load2(0); break;
213    case 3: __asan_report_load4(0); break;
214    case 4: __asan_report_load8(0); break;
215    case 5: __asan_report_load16(0); break;
216    case 6: __asan_report_store1(0); break;
217    case 7: __asan_report_store2(0); break;
218    case 8: __asan_report_store4(0); break;
219    case 9: __asan_report_store8(0); break;
220    case 10: __asan_report_store16(0); break;
221    case 11: __asan_register_global(0, 0, 0); break;
222    case 12: __asan_register_globals(0, 0); break;
223    case 13: __asan_unregister_globals(0, 0); break;
224    case 14: __asan_set_death_callback(0); break;
225    case 15: __asan_set_error_report_callback(0); break;
226    case 16: __asan_handle_no_return(); break;
227    case 17: __asan_address_is_poisoned(0); break;
228    case 18: __asan_get_allocated_size(0); break;
229    case 19: __asan_get_current_allocated_bytes(); break;
230    case 20: __asan_get_estimated_allocated_size(0); break;
231    case 21: __asan_get_free_bytes(); break;
232    case 22: __asan_get_heap_size(); break;
233    case 23: __asan_get_ownership(0); break;
234    case 24: __asan_get_unmapped_bytes(); break;
235    case 25: __asan_poison_memory_region(0, 0); break;
236    case 26: __asan_unpoison_memory_region(0, 0); break;
237    case 27: __asan_set_error_exit_code(0); break;
238    case 28: __asan_stack_free(0, 0, 0); break;
239    case 29: __asan_stack_malloc(0, 0); break;
240    case 30: __asan_set_on_error_callback(0); break;
241    case 31: __asan_default_options(); break;
242    case 32: __asan_before_dynamic_init(0, 0); break;
243    case 33: __asan_after_dynamic_init(); break;
244    case 34: __asan_malloc_hook(0, 0); break;
245    case 35: __asan_free_hook(0); break;
246    case 36: __asan_set_symbolize_callback(0); break;
247  }
248}
249
250static void asan_atexit() {
251  AsanPrintf("AddressSanitizer exit stats:\n");
252  __asan_print_accumulated_stats();
253}
254
255}  // namespace __asan
256
257// ---------------------- Interface ---------------- {{{1
258using namespace __asan;  // NOLINT
259
260int NOINLINE __asan_set_error_exit_code(int exit_code) {
261  int old = flags()->exitcode;
262  flags()->exitcode = exit_code;
263  return old;
264}
265
266void NOINLINE __asan_handle_no_return() {
267  int local_stack;
268  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
269  CHECK(curr_thread);
270  uptr top = curr_thread->stack_top();
271  uptr bottom = ((uptr)&local_stack - kPageSize) & ~(kPageSize-1);
272  PoisonShadow(bottom, top - bottom, 0);
273}
274
275void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
276  death_callback = callback;
277}
278
279void __asan_init() {
280  if (asan_inited) return;
281  CHECK(!asan_init_is_running && "ASan init calls itself!");
282  asan_init_is_running = true;
283
284  // Make sure we are not statically linked.
285  AsanDoesNotSupportStaticLinkage();
286
287  // Initialize flags. This must be done early, because most of the
288  // initialization steps look at flags().
289  const char *options = GetEnv("ASAN_OPTIONS");
290  InitializeFlags(flags(), options);
291
292  if (flags()->verbosity && options) {
293    Report("Parsed ASAN_OPTIONS: %s\n", options);
294  }
295
296  // Re-exec ourselves if we need to set additional env or command line args.
297  MaybeReexec();
298
299  // Setup internal allocator callback.
300  SetLowLevelAllocateCallback(OnLowLevelAllocate);
301
302  if (flags()->atexit) {
303    Atexit(asan_atexit);
304  }
305
306  // interceptors
307  InitializeAsanInterceptors();
308
309  ReplaceSystemMalloc();
310  ReplaceOperatorsNewAndDelete();
311
312  if (flags()->verbosity) {
313    Printf("|| `[%p, %p]` || HighMem    ||\n",
314           (void*)kHighMemBeg, (void*)kHighMemEnd);
315    Printf("|| `[%p, %p]` || HighShadow ||\n",
316           (void*)kHighShadowBeg, (void*)kHighShadowEnd);
317    Printf("|| `[%p, %p]` || ShadowGap  ||\n",
318           (void*)kShadowGapBeg, (void*)kShadowGapEnd);
319    Printf("|| `[%p, %p]` || LowShadow  ||\n",
320           (void*)kLowShadowBeg, (void*)kLowShadowEnd);
321    Printf("|| `[%p, %p]` || LowMem     ||\n",
322           (void*)kLowMemBeg, (void*)kLowMemEnd);
323    Printf("MemToShadow(shadow): %p %p %p %p\n",
324           (void*)MEM_TO_SHADOW(kLowShadowBeg),
325           (void*)MEM_TO_SHADOW(kLowShadowEnd),
326           (void*)MEM_TO_SHADOW(kHighShadowBeg),
327           (void*)MEM_TO_SHADOW(kHighShadowEnd));
328    Printf("red_zone=%zu\n", (uptr)flags()->redzone);
329    Printf("malloc_context_size=%zu\n", (uptr)flags()->malloc_context_size);
330
331    Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
332    Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
333    Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
334    CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
335  }
336
337  if (flags()->disable_core) {
338    DisableCoreDumper();
339  }
340
341  uptr shadow_start = kLowShadowBeg;
342  if (kLowShadowBeg > 0) shadow_start -= kMmapGranularity;
343  uptr shadow_end = kHighShadowEnd;
344  if (MemoryRangeIsAvailable(shadow_start, shadow_end)) {
345    if (kLowShadowBeg != kLowShadowEnd) {
346      // mmap the low shadow plus at least one page.
347      ReserveShadowMemoryRange(kLowShadowBeg - kMmapGranularity, kLowShadowEnd);
348    }
349    // mmap the high shadow.
350    ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
351    // protect the gap
352    void *prot = Mprotect(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
353    CHECK(prot == (void*)kShadowGapBeg);
354  } else {
355    Report("Shadow memory range interleaves with an existing memory mapping. "
356           "ASan cannot proceed correctly. ABORTING.\n");
357    DumpProcessMap();
358    Die();
359  }
360
361  InstallSignalHandlers();
362  // Start symbolizer process if necessary.
363  if (flags()->symbolize) {
364    const char *external_symbolizer = GetEnv("ASAN_SYMBOLIZER_PATH");
365    if (external_symbolizer) {
366      InitializeExternalSymbolizer(external_symbolizer);
367    }
368  }
369#ifdef _WIN32
370  __asan_set_symbolize_callback(WinSymbolize);
371#endif  // _WIN32
372
373  // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
374  // should be set to 1 prior to initializing the threads.
375  asan_inited = 1;
376  asan_init_is_running = false;
377
378  asanThreadRegistry().Init();
379  asanThreadRegistry().GetMain()->ThreadStart();
380  force_interface_symbols();  // no-op.
381
382  if (flags()->verbosity) {
383    Report("AddressSanitizer Init done\n");
384  }
385}
386
387#if defined(ASAN_USE_PREINIT_ARRAY)
388  // On Linux, we force __asan_init to be called before anyone else
389  // by placing it into .preinit_array section.
390  // FIXME: do we have anything like this on Mac?
391  __attribute__((section(".preinit_array")))
392    typeof(__asan_init) *__asan_preinit =__asan_init;
393#elif defined(_WIN32) && defined(_DLL)
394  // On Windows, when using dynamic CRT (/MD), we can put a pointer
395  // to __asan_init into the global list of C initializers.
396  // See crt0dat.c in the CRT sources for the details.
397  #pragma section(".CRT$XIB", long, read)  // NOLINT
398  __declspec(allocate(".CRT$XIB")) void (*__asan_preinit)() = __asan_init;
399#endif
400