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 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
  99   UNIMPLEMENTED();
 100 }
 101
 102 void ResetContextStack(void *context) { UNIMPLEMENTED(); }
 103
 104 // Support for the following functions from libdispatch on Mac OS:
 105 //   dispatch_async_f()
 106 //   dispatch_async()
 107 //   dispatch_sync_f()
 108 //   dispatch_sync()
 109 //   dispatch_after_f()
 110 //   dispatch_after()
 111 //   dispatch_group_async_f()
 112 //   dispatch_group_async()
 113 // TODO(glider): libdispatch API contains other functions that we don't support
 114 // yet.
 115 //
 116 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 117 // they can cause jobs to run on a thread different from the current one.
 118 // TODO(glider): if so, we need a test for this (otherwise we should remove
 119 // them).
 120 //
 121 // The following functions use dispatch_barrier_async_f() (which isn't a library
 122 // function but is exported) and are thus supported:
 123 //   dispatch_source_set_cancel_handler_f()
 124 //   dispatch_source_set_cancel_handler()
 125 //   dispatch_source_set_event_handler_f()
 126 //   dispatch_source_set_event_handler()
 127 //
 128 // The reference manual for Grand Central Dispatch is available at
 129 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 130 // The implementation details are at
 131 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 132
 133 typedef void* dispatch_group_t;
 134 typedef void* dispatch_queue_t;
 135 typedef void* dispatch_source_t;
 136 typedef u64 dispatch_time_t;
 137 typedef void (*dispatch_function_t)(void *block);
 138 typedef void* (*worker_t)(void *block);
 139
 140 // A wrapper for the ObjC blocks used to support libdispatch.
 141 typedef struct {
 142   void *block;
 143   dispatch_function_t func;
 144   u32 parent_tid;
 145 } asan_block_context_t;
 146
 147 ALWAYS_INLINE
 148 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 149   AsanThread *t = GetCurrentThread();
 150   if (!t) {
 151     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
 152                            parent_tid, stack, /* detached */ true);
 153     t->Init();
 154     asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
 155                                      nullptr);
 156     SetCurrentThread(t);
 157   }
 158 }
 159
 160 // For use by only those functions that allocated the context via
 161 // alloc_asan_context().
 162 extern "C"
 163 void asan_dispatch_call_block_and_release(void *block) {
 164   GET_STACK_TRACE_THREAD;
 165   asan_block_context_t *context = (asan_block_context_t*)block;
 166   VReport(2,
 167           "asan_dispatch_call_block_and_release(): "
 168           "context: %p, pthread_self: %p\n",
 169           block, pthread_self());
 170   asan_register_worker_thread(context->parent_tid, &stack);
 171   // Call the original dispatcher for the block.
 172   context->func(context->block);
 173   asan_free(context, &stack, FROM_MALLOC);
 174 }
 175
 176 }  // namespace __asan
 177
 178 using namespace __asan;
 179
 180 // Wrap |ctxt| and |func| into an asan_block_context_t.
 181 // The caller retains control of the allocated context.
 182 extern "C"
 183 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 184                                          BufferedStackTrace *stack) {
 185   asan_block_context_t *asan_ctxt =
 186       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 187   asan_ctxt->block = ctxt;
 188   asan_ctxt->func = func;
 189   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 190   return asan_ctxt;
 191 }
 192
 193 // Define interceptor for dispatch_*_f function with the three most common
 194 // parameters: dispatch_queue_t, context, dispatch_function_t.
 195 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 196   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 197                                   dispatch_function_t func) {                 \
 198     GET_STACK_TRACE_THREAD;                                                   \
 199     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 200     if (Verbosity() >= 2) {                                     \
 201       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 202              asan_ctxt, pthread_self());                                      \
 203       PRINT_CURRENT_STACK();                                                  \
 204     }                                                                         \
 205     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 206                               asan_dispatch_call_block_and_release);          \
 207   }
 208
 209 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 210 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 211 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 212
 213 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 214                                     dispatch_queue_t dq, void *ctxt,
 215                                     dispatch_function_t func) {
 216   GET_STACK_TRACE_THREAD;
 217   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 218   if (Verbosity() >= 2) {
 219     Report("dispatch_after_f: %p\n", asan_ctxt);
 220     PRINT_CURRENT_STACK();
 221   }
 222   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 223                                 asan_dispatch_call_block_and_release);
 224 }
 225
 226 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 227                                           dispatch_queue_t dq, void *ctxt,
 228                                           dispatch_function_t func) {
 229   GET_STACK_TRACE_THREAD;
 230   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 231   if (Verbosity() >= 2) {
 232     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 233            asan_ctxt, pthread_self());
 234     PRINT_CURRENT_STACK();
 235   }
 236   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 237                                asan_dispatch_call_block_and_release);
 238 }
 239
 240 #if !defined(MISSING_BLOCKS_SUPPORT)
 241 extern "C" {
 242 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 243 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 244                           void(^work)(void));
 245 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 246                     void(^work)(void));
 247 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 248                                         void(^work)(void));
 249 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 250 }
 251
 252 #define GET_ASAN_BLOCK(work) \
 253   void (^asan_block)(void);  \
 254   int parent_tid = GetCurrentTidOrInvalid(); \
 255   asan_block = ^(void) { \
 256     GET_STACK_TRACE_THREAD; \
 257     asan_register_worker_thread(parent_tid, &stack); \
 258     work(); \
 259   }
 260
 261 INTERCEPTOR(void, dispatch_async,
 262             dispatch_queue_t dq, void(^work)(void)) {
 263   ENABLE_FRAME_POINTER;
 264   GET_ASAN_BLOCK(work);
 265   REAL(dispatch_async)(dq, asan_block);
 266 }
 267
 268 INTERCEPTOR(void, dispatch_group_async,
 269             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 270   ENABLE_FRAME_POINTER;
 271   GET_ASAN_BLOCK(work);
 272   REAL(dispatch_group_async)(dg, dq, asan_block);
 273 }
 274
 275 INTERCEPTOR(void, dispatch_after,
 276             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 277   ENABLE_FRAME_POINTER;
 278   GET_ASAN_BLOCK(work);
 279   REAL(dispatch_after)(when, queue, asan_block);
 280 }
 281
 282 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 283             dispatch_source_t ds, void(^work)(void)) {
 284   if (!work) {
 285     REAL(dispatch_source_set_cancel_handler)(ds, work);
 286     return;
 287   }
 288   ENABLE_FRAME_POINTER;
 289   GET_ASAN_BLOCK(work);
 290   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 291 }
 292
 293 INTERCEPTOR(void, dispatch_source_set_event_handler,
 294             dispatch_source_t ds, void(^work)(void)) {
 295   ENABLE_FRAME_POINTER;
 296   GET_ASAN_BLOCK(work);
 297   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 298 }
 299 #endif
 300
 301 #endif  // SANITIZER_APPLE