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 max_occupied_addr = 0;
  64   VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
  65   uptr shadow_start =
  66       FindAvailableMemoryRange(space_size, alignment, granularity,
  67                                &largest_gap_found, &max_occupied_addr);
  68   // If the shadow doesn't fit, restrict the address space to make it fit.
  69   if (shadow_start == 0) {
  70     VReport(
  71         2,
  72         "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
  73         largest_gap_found, max_occupied_addr);
  74     uptr new_max_vm = RoundDownTo(largest_gap_found << SHADOW_SCALE, alignment);
  75     if (new_max_vm < max_occupied_addr) {
  76       Report("Unable to find a memory range for dynamic shadow.\n");
  77       Report(
  78           "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
  79           "new_max_vm = %p\n",
  80           space_size, largest_gap_found, max_occupied_addr, new_max_vm);
  81       CHECK(0 && "cannot place shadow");
  82     }
  83     RestrictMemoryToMaxAddress(new_max_vm);
  84     kHighMemEnd = new_max_vm - 1;
  85     space_size = kHighShadowEnd + left_padding;
  86     VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
  87     shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
  88                                             nullptr, nullptr);
  89     if (shadow_start == 0) {
  90       Report("Unable to find a memory range after restricting VM.\n");
  91       CHECK(0 && "cannot place shadow after restricting vm");
  92     }
  93   }
  94   CHECK_NE((uptr)0, shadow_start);
  95   CHECK(IsAligned(shadow_start, alignment));
  96   return shadow_start;
  97 }
  98
  99 // No-op. Mac does not support static linkage anyway.
 100 void AsanCheckDynamicRTPrereqs() {}
 101
 102 // No-op. Mac does not support static linkage anyway.
 103 void AsanCheckIncompatibleRT() {}
 104
 105 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 106   // Find the Mach-O header for the image containing the needle
 107   Dl_info info;
 108   int err = dladdr(needle, &info);
 109   if (err == 0) return;
 110
 111 #if __LP64__
 112   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
 113 #else
 114   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
 115 #endif
 116
 117   // Look up the __asan_globals section in that image and register its globals
 118   unsigned long size = 0;
 119   __asan_global *globals = (__asan_global *)getsectiondata(
 120       mh,
 121       "__DATA", "__asan_globals",
 122       &size);
 123
 124   if (!globals) return;
 125   if (size % sizeof(__asan_global) != 0) return;
 126   op(globals, size / sizeof(__asan_global));
 127 }
 128
 129 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 130   UNIMPLEMENTED();
 131 }
 132
 133 // Support for the following functions from libdispatch on Mac OS:
 134 //   dispatch_async_f()
 135 //   dispatch_async()
 136 //   dispatch_sync_f()
 137 //   dispatch_sync()
 138 //   dispatch_after_f()
 139 //   dispatch_after()
 140 //   dispatch_group_async_f()
 141 //   dispatch_group_async()
 142 // TODO(glider): libdispatch API contains other functions that we don't support
 143 // yet.
 144 //
 145 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 146 // they can cause jobs to run on a thread different from the current one.
 147 // TODO(glider): if so, we need a test for this (otherwise we should remove
 148 // them).
 149 //
 150 // The following functions use dispatch_barrier_async_f() (which isn't a library
 151 // function but is exported) and are thus supported:
 152 //   dispatch_source_set_cancel_handler_f()
 153 //   dispatch_source_set_cancel_handler()
 154 //   dispatch_source_set_event_handler_f()
 155 //   dispatch_source_set_event_handler()
 156 //
 157 // The reference manual for Grand Central Dispatch is available at
 158 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 159 // The implementation details are at
 160 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 161
 162 typedef void* dispatch_group_t;
 163 typedef void* dispatch_queue_t;
 164 typedef void* dispatch_source_t;
 165 typedef u64 dispatch_time_t;
 166 typedef void (*dispatch_function_t)(void *block);
 167 typedef void* (*worker_t)(void *block);
 168
 169 // A wrapper for the ObjC blocks used to support libdispatch.
 170 typedef struct {
 171   void *block;
 172   dispatch_function_t func;
 173   u32 parent_tid;
 174 } asan_block_context_t;
 175
 176 ALWAYS_INLINE
 177 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 178   AsanThread *t = GetCurrentThread();
 179   if (!t) {
 180     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
 181                            parent_tid, stack, /* detached */ true);
 182     t->Init();
 183     asanThreadRegistry().StartThread(t->tid(), GetTid(),
 184                                      /* workerthread */ true, 0);
 185     SetCurrentThread(t);
 186   }
 187 }
 188
 189 // For use by only those functions that allocated the context via
 190 // alloc_asan_context().
 191 extern "C"
 192 void asan_dispatch_call_block_and_release(void *block) {
 193   GET_STACK_TRACE_THREAD;
 194   asan_block_context_t *context = (asan_block_context_t*)block;
 195   VReport(2,
 196           "asan_dispatch_call_block_and_release(): "
 197           "context: %p, pthread_self: %p\n",
 198           block, pthread_self());
 199   asan_register_worker_thread(context->parent_tid, &stack);
 200   // Call the original dispatcher for the block.
 201   context->func(context->block);
 202   asan_free(context, &stack, FROM_MALLOC);
 203 }
 204
 205 }  // namespace __asan
 206
 207 using namespace __asan;  // NOLINT
 208
 209 // Wrap |ctxt| and |func| into an asan_block_context_t.
 210 // The caller retains control of the allocated context.
 211 extern "C"
 212 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 213                                          BufferedStackTrace *stack) {
 214   asan_block_context_t *asan_ctxt =
 215       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 216   asan_ctxt->block = ctxt;
 217   asan_ctxt->func = func;
 218   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 219   return asan_ctxt;
 220 }
 221
 222 // Define interceptor for dispatch_*_f function with the three most common
 223 // parameters: dispatch_queue_t, context, dispatch_function_t.
 224 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 225   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 226                                   dispatch_function_t func) {                 \
 227     GET_STACK_TRACE_THREAD;                                                   \
 228     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 229     if (Verbosity() >= 2) {                                     \
 230       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 231              asan_ctxt, pthread_self());                                      \
 232       PRINT_CURRENT_STACK();                                                  \
 233     }                                                                         \
 234     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 235                               asan_dispatch_call_block_and_release);          \
 236   }
 237
 238 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 239 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 240 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 241
 242 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 243                                     dispatch_queue_t dq, void *ctxt,
 244                                     dispatch_function_t func) {
 245   GET_STACK_TRACE_THREAD;
 246   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 247   if (Verbosity() >= 2) {
 248     Report("dispatch_after_f: %p\n", asan_ctxt);
 249     PRINT_CURRENT_STACK();
 250   }
 251   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 252                                 asan_dispatch_call_block_and_release);
 253 }
 254
 255 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 256                                           dispatch_queue_t dq, void *ctxt,
 257                                           dispatch_function_t func) {
 258   GET_STACK_TRACE_THREAD;
 259   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 260   if (Verbosity() >= 2) {
 261     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 262            asan_ctxt, pthread_self());
 263     PRINT_CURRENT_STACK();
 264   }
 265   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 266                                asan_dispatch_call_block_and_release);
 267 }
 268
 269 #if !defined(MISSING_BLOCKS_SUPPORT)
 270 extern "C" {
 271 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 272 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 273                           void(^work)(void));
 274 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 275                     void(^work)(void));
 276 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 277                                         void(^work)(void));
 278 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 279 }
 280
 281 #define GET_ASAN_BLOCK(work) \
 282   void (^asan_block)(void);  \
 283   int parent_tid = GetCurrentTidOrInvalid(); \
 284   asan_block = ^(void) { \
 285     GET_STACK_TRACE_THREAD; \
 286     asan_register_worker_thread(parent_tid, &stack); \
 287     work(); \
 288   }
 289
 290 INTERCEPTOR(void, dispatch_async,
 291             dispatch_queue_t dq, void(^work)(void)) {
 292   ENABLE_FRAME_POINTER;
 293   GET_ASAN_BLOCK(work);
 294   REAL(dispatch_async)(dq, asan_block);
 295 }
 296
 297 INTERCEPTOR(void, dispatch_group_async,
 298             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 299   ENABLE_FRAME_POINTER;
 300   GET_ASAN_BLOCK(work);
 301   REAL(dispatch_group_async)(dg, dq, asan_block);
 302 }
 303
 304 INTERCEPTOR(void, dispatch_after,
 305             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 306   ENABLE_FRAME_POINTER;
 307   GET_ASAN_BLOCK(work);
 308   REAL(dispatch_after)(when, queue, asan_block);
 309 }
 310
 311 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 312             dispatch_source_t ds, void(^work)(void)) {
 313   if (!work) {
 314     REAL(dispatch_source_set_cancel_handler)(ds, work);
 315     return;
 316   }
 317   ENABLE_FRAME_POINTER;
 318   GET_ASAN_BLOCK(work);
 319   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 320 }
 321
 322 INTERCEPTOR(void, dispatch_source_set_event_handler,
 323             dispatch_source_t ds, void(^work)(void)) {
 324   ENABLE_FRAME_POINTER;
 325   GET_ASAN_BLOCK(work);
 326   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 327 }
 328 #endif
 329
 330 #endif  // SANITIZER_MAC