libsanitizer/asan/asan_mac.cpp

   1 //===-- asan_mac.cpp ------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of AddressSanitizer, an address sanity checker.
  10 //
  11 // Mac-specific details.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_APPLE
  16
  17 #include "asan_interceptors.h"
  18 #include "asan_internal.h"
  19 #include "asan_mapping.h"
  20 #include "asan_stack.h"
  21 #include "asan_thread.h"
  22 #include "sanitizer_common/sanitizer_atomic.h"
  23 #include "sanitizer_common/sanitizer_libc.h"
  24 #include "sanitizer_common/sanitizer_mac.h"
  25
  26 #include <dlfcn.h>
  27 #include <fcntl.h>
  28 #include <libkern/OSAtomic.h>
  29 #include <mach-o/dyld.h>
  30 #include <mach-o/getsect.h>
  31 #include <mach-o/loader.h>
  32 #include <pthread.h>
  33 #include <stdlib.h>  // for free()
  34 #include <sys/mman.h>
  35 #include <sys/resource.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/ucontext.h>
  38 #include <unistd.h>
  39
  40 // from <crt_externs.h>, but we don't have that file on iOS
  41 extern "C" {
  42   extern char ***_NSGetArgv(void);
  43   extern char ***_NSGetEnviron(void);
  44 }
  45
  46 namespace __asan {
  47
  48 void InitializePlatformInterceptors() {}
  49 void InitializePlatformExceptionHandlers() {}
  50 bool IsSystemHeapAddress (uptr addr) { return false; }
  51
  52 // No-op. Mac does not support static linkage anyway.
  53 void *AsanDoesNotSupportStaticLinkage() {
  54   return 0;
  55 }
  56
  57 uptr FindDynamicShadowStart() {
  58   return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
  59                           /*min_shadow_base_alignment*/ 0, kHighMemEnd);
  60 }
  61
  62 // No-op. Mac does not support static linkage anyway.
  63 void AsanCheckDynamicRTPrereqs() {}
  64
  65 // No-op. Mac does not support static linkage anyway.
  66 void AsanCheckIncompatibleRT() {}
  67
  68 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
  69   // Find the Mach-O header for the image containing the needle
  70   Dl_info info;
  71   int err = dladdr(needle, &info);
  72   if (err == 0) return;
  73
  74 #if __LP64__
  75   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
  76 #else
  77   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
  78 #endif
  79
  80   // Look up the __asan_globals section in that image and register its globals
  81   unsigned long size = 0;
  82   __asan_global *globals = (__asan_global *)getsectiondata(
  83       mh,
  84       "__DATA", "__asan_globals",
  85       &size);
  86
  87   if (!globals) return;
  88   if (size % sizeof(__asan_global) != 0) return;
  89   op(globals, size / sizeof(__asan_global));
  90 }
  91
  92 void FlushUnneededASanShadowMemory(uptr p, uptr size) {
  93   // Since asan's mapping is compacting, the shadow chunk may be
  94   // not page-aligned, so we only flush the page-aligned portion.
  95   ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
  96 }
  97
  98 // Support for the following functions from libdispatch on Mac OS:
  99 //   dispatch_async_f()
 100 //   dispatch_async()
 101 //   dispatch_sync_f()
 102 //   dispatch_sync()
 103 //   dispatch_after_f()
 104 //   dispatch_after()
 105 //   dispatch_group_async_f()
 106 //   dispatch_group_async()
 107 // TODO(glider): libdispatch API contains other functions that we don't support
 108 // yet.
 109 //
 110 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 111 // they can cause jobs to run on a thread different from the current one.
 112 // TODO(glider): if so, we need a test for this (otherwise we should remove
 113 // them).
 114 //
 115 // The following functions use dispatch_barrier_async_f() (which isn't a library
 116 // function but is exported) and are thus supported:
 117 //   dispatch_source_set_cancel_handler_f()
 118 //   dispatch_source_set_cancel_handler()
 119 //   dispatch_source_set_event_handler_f()
 120 //   dispatch_source_set_event_handler()
 121 //
 122 // The reference manual for Grand Central Dispatch is available at
 123 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 124 // The implementation details are at
 125 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 126
 127 typedef void* dispatch_group_t;
 128 typedef void* dispatch_queue_t;
 129 typedef void* dispatch_source_t;
 130 typedef u64 dispatch_time_t;
 131 typedef void (*dispatch_function_t)(void *block);
 132 typedef void* (*worker_t)(void *block);
 133
 134 // A wrapper for the ObjC blocks used to support libdispatch.
 135 typedef struct {
 136   void *block;
 137   dispatch_function_t func;
 138   u32 parent_tid;
 139 } asan_block_context_t;
 140
 141 ALWAYS_INLINE
 142 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 143   AsanThread *t = GetCurrentThread();
 144   if (!t) {
 145     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
 146                            parent_tid, stack, /* detached */ true);
 147     t->Init();
 148     asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
 149                                      nullptr);
 150     SetCurrentThread(t);
 151   }
 152 }
 153
 154 // For use by only those functions that allocated the context via
 155 // alloc_asan_context().
 156 extern "C"
 157 void asan_dispatch_call_block_and_release(void *block) {
 158   GET_STACK_TRACE_THREAD;
 159   asan_block_context_t *context = (asan_block_context_t*)block;
 160   VReport(2,
 161           "asan_dispatch_call_block_and_release(): "
 162           "context: %p, pthread_self: %p\n",
 163           block, pthread_self());
 164   asan_register_worker_thread(context->parent_tid, &stack);
 165   // Call the original dispatcher for the block.
 166   context->func(context->block);
 167   asan_free(context, &stack, FROM_MALLOC);
 168 }
 169
 170 }  // namespace __asan
 171
 172 using namespace __asan;
 173
 174 // Wrap |ctxt| and |func| into an asan_block_context_t.
 175 // The caller retains control of the allocated context.
 176 extern "C"
 177 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 178                                          BufferedStackTrace *stack) {
 179   asan_block_context_t *asan_ctxt =
 180       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 181   asan_ctxt->block = ctxt;
 182   asan_ctxt->func = func;
 183   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 184   return asan_ctxt;
 185 }
 186
 187 // Define interceptor for dispatch_*_f function with the three most common
 188 // parameters: dispatch_queue_t, context, dispatch_function_t.
 189 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 190   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 191                                   dispatch_function_t func) {                 \
 192     GET_STACK_TRACE_THREAD;                                                   \
 193     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 194     if (Verbosity() >= 2) {                                     \
 195       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 196              asan_ctxt, pthread_self());                                      \
 197       PRINT_CURRENT_STACK();                                                  \
 198     }                                                                         \
 199     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 200                               asan_dispatch_call_block_and_release);          \
 201   }
 202
 203 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 204 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 205 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 206
 207 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 208                                     dispatch_queue_t dq, void *ctxt,
 209                                     dispatch_function_t func) {
 210   GET_STACK_TRACE_THREAD;
 211   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 212   if (Verbosity() >= 2) {
 213     Report("dispatch_after_f: %p\n", asan_ctxt);
 214     PRINT_CURRENT_STACK();
 215   }
 216   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 217                                 asan_dispatch_call_block_and_release);
 218 }
 219
 220 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 221                                           dispatch_queue_t dq, void *ctxt,
 222                                           dispatch_function_t func) {
 223   GET_STACK_TRACE_THREAD;
 224   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 225   if (Verbosity() >= 2) {
 226     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 227            asan_ctxt, pthread_self());
 228     PRINT_CURRENT_STACK();
 229   }
 230   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 231                                asan_dispatch_call_block_and_release);
 232 }
 233
 234 #if !defined(MISSING_BLOCKS_SUPPORT)
 235 extern "C" {
 236 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 237 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 238                           void(^work)(void));
 239 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 240                     void(^work)(void));
 241 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 242                                         void(^work)(void));
 243 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 244 }
 245
 246 #define GET_ASAN_BLOCK(work) \
 247   void (^asan_block)(void);  \
 248   int parent_tid = GetCurrentTidOrInvalid(); \
 249   asan_block = ^(void) { \
 250     GET_STACK_TRACE_THREAD; \
 251     asan_register_worker_thread(parent_tid, &stack); \
 252     work(); \
 253   }
 254
 255 INTERCEPTOR(void, dispatch_async,
 256             dispatch_queue_t dq, void(^work)(void)) {
 257   ENABLE_FRAME_POINTER;
 258   GET_ASAN_BLOCK(work);
 259   REAL(dispatch_async)(dq, asan_block);
 260 }
 261
 262 INTERCEPTOR(void, dispatch_group_async,
 263             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 264   ENABLE_FRAME_POINTER;
 265   GET_ASAN_BLOCK(work);
 266   REAL(dispatch_group_async)(dg, dq, asan_block);
 267 }
 268
 269 INTERCEPTOR(void, dispatch_after,
 270             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 271   ENABLE_FRAME_POINTER;
 272   GET_ASAN_BLOCK(work);
 273   REAL(dispatch_after)(when, queue, asan_block);
 274 }
 275
 276 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 277             dispatch_source_t ds, void(^work)(void)) {
 278   if (!work) {
 279     REAL(dispatch_source_set_cancel_handler)(ds, work);
 280     return;
 281   }
 282   ENABLE_FRAME_POINTER;
 283   GET_ASAN_BLOCK(work);
 284   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 285 }
 286
 287 INTERCEPTOR(void, dispatch_source_set_event_handler,
 288             dispatch_source_t ds, void(^work)(void)) {
 289   ENABLE_FRAME_POINTER;
 290   GET_ASAN_BLOCK(work);
 291   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 292 }
 293 #endif
 294
 295 #endif  // SANITIZER_APPLE