libsanitizer/asan/asan_mac.cc

   1 //===-- asan_mac.cc -------------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Mac-specific details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_MAC
  15
  16 #include "asan_interceptors.h"
  17 #include "asan_internal.h"
  18 #include "asan_mapping.h"
  19 #include "asan_stack.h"
  20 #include "asan_thread.h"
  21 #include "sanitizer_common/sanitizer_atomic.h"
  22 #include "sanitizer_common/sanitizer_libc.h"
  23 #include "sanitizer_common/sanitizer_mac.h"
  24
  25 #include <dlfcn.h>
  26 #include <fcntl.h>
  27 #include <libkern/OSAtomic.h>
  28 #include <mach-o/dyld.h>
  29 #include <mach-o/getsect.h>
  30 #include <mach-o/loader.h>
  31 #include <pthread.h>
  32 #include <stdlib.h>  // for free()
  33 #include <sys/mman.h>
  34 #include <sys/resource.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/ucontext.h>
  37 #include <unistd.h>
  38
  39 // from <crt_externs.h>, but we don't have that file on iOS
  40 extern "C" {
  41   extern char ***_NSGetArgv(void);
  42   extern char ***_NSGetEnviron(void);
  43 }
  44
  45 namespace __asan {
  46
  47 void InitializePlatformInterceptors() {}
  48 void InitializePlatformExceptionHandlers() {}
  49 bool IsSystemHeapAddress (uptr addr) { return false; }
  50
  51 // No-op. Mac does not support static linkage anyway.
  52 void *AsanDoesNotSupportStaticLinkage() {
  53   return 0;
  54 }
  55
  56 uptr FindDynamicShadowStart() {
  57   uptr granularity = GetMmapGranularity();
  58   uptr alignment = 8 * granularity;
  59   uptr left_padding = granularity;
  60   uptr space_size = kHighShadowEnd + left_padding;
  61
  62   uptr largest_gap_found = 0;
  63   uptr shadow_start = FindAvailableMemoryRange(space_size, alignment,
  64                                                granularity, &largest_gap_found);
  65   // If the shadow doesn't fit, restrict the address space to make it fit.
  66   if (shadow_start == 0) {
  67     uptr new_max_vm = RoundDownTo(largest_gap_found << SHADOW_SCALE, alignment);
  68     RestrictMemoryToMaxAddress(new_max_vm);
  69     kHighMemEnd = new_max_vm - 1;
  70     space_size = kHighShadowEnd + left_padding;
  71     shadow_start =
  72         FindAvailableMemoryRange(space_size, alignment, granularity, nullptr);
  73   }
  74   CHECK_NE((uptr)0, shadow_start);
  75   CHECK(IsAligned(shadow_start, alignment));
  76   return shadow_start;
  77 }
  78
  79 // No-op. Mac does not support static linkage anyway.
  80 void AsanCheckDynamicRTPrereqs() {}
  81
  82 // No-op. Mac does not support static linkage anyway.
  83 void AsanCheckIncompatibleRT() {}
  84
  85 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
  86   // Find the Mach-O header for the image containing the needle
  87   Dl_info info;
  88   int err = dladdr(needle, &info);
  89   if (err == 0) return;
  90
  91 #if __LP64__
  92   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
  93 #else
  94   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
  95 #endif
  96
  97   // Look up the __asan_globals section in that image and register its globals
  98   unsigned long size = 0;
  99   __asan_global *globals = (__asan_global *)getsectiondata(
 100       mh,
 101       "__DATA", "__asan_globals",
 102       &size);
 103
 104   if (!globals) return;
 105   if (size % sizeof(__asan_global) != 0) return;
 106   op(globals, size / sizeof(__asan_global));
 107 }
 108
 109 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 110   UNIMPLEMENTED();
 111 }
 112
 113 // Support for the following functions from libdispatch on Mac OS:
 114 //   dispatch_async_f()
 115 //   dispatch_async()
 116 //   dispatch_sync_f()
 117 //   dispatch_sync()
 118 //   dispatch_after_f()
 119 //   dispatch_after()
 120 //   dispatch_group_async_f()
 121 //   dispatch_group_async()
 122 // TODO(glider): libdispatch API contains other functions that we don't support
 123 // yet.
 124 //
 125 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 126 // they can cause jobs to run on a thread different from the current one.
 127 // TODO(glider): if so, we need a test for this (otherwise we should remove
 128 // them).
 129 //
 130 // The following functions use dispatch_barrier_async_f() (which isn't a library
 131 // function but is exported) and are thus supported:
 132 //   dispatch_source_set_cancel_handler_f()
 133 //   dispatch_source_set_cancel_handler()
 134 //   dispatch_source_set_event_handler_f()
 135 //   dispatch_source_set_event_handler()
 136 //
 137 // The reference manual for Grand Central Dispatch is available at
 138 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 139 // The implementation details are at
 140 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 141
 142 typedef void* dispatch_group_t;
 143 typedef void* dispatch_queue_t;
 144 typedef void* dispatch_source_t;
 145 typedef u64 dispatch_time_t;
 146 typedef void (*dispatch_function_t)(void *block);
 147 typedef void* (*worker_t)(void *block);
 148
 149 // A wrapper for the ObjC blocks used to support libdispatch.
 150 typedef struct {
 151   void *block;
 152   dispatch_function_t func;
 153   u32 parent_tid;
 154 } asan_block_context_t;
 155
 156 ALWAYS_INLINE
 157 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 158   AsanThread *t = GetCurrentThread();
 159   if (!t) {
 160     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
 161                            parent_tid, stack, /* detached */ true);
 162     t->Init();
 163     asanThreadRegistry().StartThread(t->tid(), GetTid(),
 164                                      /* workerthread */ true, 0);
 165     SetCurrentThread(t);
 166   }
 167 }
 168
 169 // For use by only those functions that allocated the context via
 170 // alloc_asan_context().
 171 extern "C"
 172 void asan_dispatch_call_block_and_release(void *block) {
 173   GET_STACK_TRACE_THREAD;
 174   asan_block_context_t *context = (asan_block_context_t*)block;
 175   VReport(2,
 176           "asan_dispatch_call_block_and_release(): "
 177           "context: %p, pthread_self: %p\n",
 178           block, pthread_self());
 179   asan_register_worker_thread(context->parent_tid, &stack);
 180   // Call the original dispatcher for the block.
 181   context->func(context->block);
 182   asan_free(context, &stack, FROM_MALLOC);
 183 }
 184
 185 }  // namespace __asan
 186
 187 using namespace __asan;  // NOLINT
 188
 189 // Wrap |ctxt| and |func| into an asan_block_context_t.
 190 // The caller retains control of the allocated context.
 191 extern "C"
 192 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 193                                          BufferedStackTrace *stack) {
 194   asan_block_context_t *asan_ctxt =
 195       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 196   asan_ctxt->block = ctxt;
 197   asan_ctxt->func = func;
 198   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 199   return asan_ctxt;
 200 }
 201
 202 // Define interceptor for dispatch_*_f function with the three most common
 203 // parameters: dispatch_queue_t, context, dispatch_function_t.
 204 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 205   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 206                                   dispatch_function_t func) {                 \
 207     GET_STACK_TRACE_THREAD;                                                   \
 208     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 209     if (Verbosity() >= 2) {                                     \
 210       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 211              asan_ctxt, pthread_self());                                      \
 212       PRINT_CURRENT_STACK();                                                  \
 213     }                                                                         \
 214     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 215                               asan_dispatch_call_block_and_release);          \
 216   }
 217
 218 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 219 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 220 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 221
 222 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 223                                     dispatch_queue_t dq, void *ctxt,
 224                                     dispatch_function_t func) {
 225   GET_STACK_TRACE_THREAD;
 226   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 227   if (Verbosity() >= 2) {
 228     Report("dispatch_after_f: %p\n", asan_ctxt);
 229     PRINT_CURRENT_STACK();
 230   }
 231   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 232                                 asan_dispatch_call_block_and_release);
 233 }
 234
 235 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 236                                           dispatch_queue_t dq, void *ctxt,
 237                                           dispatch_function_t func) {
 238   GET_STACK_TRACE_THREAD;
 239   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 240   if (Verbosity() >= 2) {
 241     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 242            asan_ctxt, pthread_self());
 243     PRINT_CURRENT_STACK();
 244   }
 245   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 246                                asan_dispatch_call_block_and_release);
 247 }
 248
 249 #if !defined(MISSING_BLOCKS_SUPPORT)
 250 extern "C" {
 251 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 252 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 253                           void(^work)(void));
 254 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 255                     void(^work)(void));
 256 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 257                                         void(^work)(void));
 258 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 259 }
 260
 261 #define GET_ASAN_BLOCK(work) \
 262   void (^asan_block)(void);  \
 263   int parent_tid = GetCurrentTidOrInvalid(); \
 264   asan_block = ^(void) { \
 265     GET_STACK_TRACE_THREAD; \
 266     asan_register_worker_thread(parent_tid, &stack); \
 267     work(); \
 268   }
 269
 270 INTERCEPTOR(void, dispatch_async,
 271             dispatch_queue_t dq, void(^work)(void)) {
 272   ENABLE_FRAME_POINTER;
 273   GET_ASAN_BLOCK(work);
 274   REAL(dispatch_async)(dq, asan_block);
 275 }
 276
 277 INTERCEPTOR(void, dispatch_group_async,
 278             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 279   ENABLE_FRAME_POINTER;
 280   GET_ASAN_BLOCK(work);
 281   REAL(dispatch_group_async)(dg, dq, asan_block);
 282 }
 283
 284 INTERCEPTOR(void, dispatch_after,
 285             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 286   ENABLE_FRAME_POINTER;
 287   GET_ASAN_BLOCK(work);
 288   REAL(dispatch_after)(when, queue, asan_block);
 289 }
 290
 291 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 292             dispatch_source_t ds, void(^work)(void)) {
 293   if (!work) {
 294     REAL(dispatch_source_set_cancel_handler)(ds, work);
 295     return;
 296   }
 297   ENABLE_FRAME_POINTER;
 298   GET_ASAN_BLOCK(work);
 299   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 300 }
 301
 302 INTERCEPTOR(void, dispatch_source_set_event_handler,
 303             dispatch_source_t ds, void(^work)(void)) {
 304   ENABLE_FRAME_POINTER;
 305   GET_ASAN_BLOCK(work);
 306   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 307 }
 308 #endif
 309
 310 #endif  // SANITIZER_MAC