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 uptr FindDynamicShadowStart() {
  53   return MapDynamicShadow(MemToShadowSize(kHighMemEnd), ASAN_SHADOW_SCALE,
  54                           /*min_shadow_base_alignment*/ 0, kHighMemEnd,
  55                           GetMmapGranularity());
  56 }
  57
  58 // No-op. Mac does not support static linkage anyway.
  59 void AsanCheckDynamicRTPrereqs() {}
  60
  61 // No-op. Mac does not support static linkage anyway.
  62 void AsanCheckIncompatibleRT() {}
  63
  64 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
  65   // Find the Mach-O header for the image containing the needle
  66   Dl_info info;
  67   int err = dladdr(needle, &info);
  68   if (err == 0) return;
  69
  70 #if __LP64__
  71   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
  72 #else
  73   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
  74 #endif
  75
  76   // Look up the __asan_globals section in that image and register its globals
  77   unsigned long size = 0;
  78   __asan_global *globals = (__asan_global *)getsectiondata(
  79       mh,
  80       "__DATA", "__asan_globals",
  81       &size);
  82
  83   if (!globals) return;
  84   if (size % sizeof(__asan_global) != 0) return;
  85   op(globals, size / sizeof(__asan_global));
  86 }
  87
  88 void FlushUnneededASanShadowMemory(uptr p, uptr size) {
  89   // Since asan's mapping is compacting, the shadow chunk may be
  90   // not page-aligned, so we only flush the page-aligned portion.
  91   ReleaseMemoryPagesToOS(MemToShadow(p), MemToShadow(p + size));
  92 }
  93
  94 // Support for the following functions from libdispatch on Mac OS:
  95 //   dispatch_async_f()
  96 //   dispatch_async()
  97 //   dispatch_sync_f()
  98 //   dispatch_sync()
  99 //   dispatch_after_f()
 100 //   dispatch_after()
 101 //   dispatch_group_async_f()
 102 //   dispatch_group_async()
 103 // TODO(glider): libdispatch API contains other functions that we don't support
 104 // yet.
 105 //
 106 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 107 // they can cause jobs to run on a thread different from the current one.
 108 // TODO(glider): if so, we need a test for this (otherwise we should remove
 109 // them).
 110 //
 111 // The following functions use dispatch_barrier_async_f() (which isn't a library
 112 // function but is exported) and are thus supported:
 113 //   dispatch_source_set_cancel_handler_f()
 114 //   dispatch_source_set_cancel_handler()
 115 //   dispatch_source_set_event_handler_f()
 116 //   dispatch_source_set_event_handler()
 117 //
 118 // The reference manual for Grand Central Dispatch is available at
 119 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 120 // The implementation details are at
 121 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 122
 123 typedef void* dispatch_group_t;
 124 typedef void* dispatch_queue_t;
 125 typedef void* dispatch_source_t;
 126 typedef u64 dispatch_time_t;
 127 typedef void (*dispatch_function_t)(void *block);
 128 typedef void* (*worker_t)(void *block);
 129 typedef unsigned long dispatch_mach_reason;
 130 typedef void *dispatch_mach_msg_t;
 131 typedef int mach_error_t;
 132 typedef void *dispatch_mach_t;
 133
 134 typedef void (*dispatch_mach_handler_function_t)(void *context,
 135                                                  dispatch_mach_reason reason,
 136                                                  dispatch_mach_msg_t message,
 137                                                  mach_error_t error);
 138 #  if !defined(MISSING_BLOCKS_SUPPORT)
 139 typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
 140                                         dispatch_mach_msg_t message,
 141                                         mach_error_t error);
 142 #  endif
 143
 144 // A wrapper for the ObjC blocks used to support libdispatch.
 145 typedef struct {
 146   void *block;
 147   dispatch_function_t func;
 148   u32 parent_tid;
 149 } asan_block_context_t;
 150
 151 ALWAYS_INLINE
 152 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 153   AsanThread *t = GetCurrentThread();
 154   if (!t) {
 155     t = AsanThread::Create(parent_tid, stack, /* detached */ true);
 156     t->Init();
 157     asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
 158                                      nullptr);
 159     SetCurrentThread(t);
 160   }
 161 }
 162
 163 // For use by only those functions that allocated the context via
 164 // alloc_asan_context().
 165 extern "C"
 166 void asan_dispatch_call_block_and_release(void *block) {
 167   GET_STACK_TRACE_THREAD;
 168   asan_block_context_t *context = (asan_block_context_t*)block;
 169   VReport(2,
 170           "asan_dispatch_call_block_and_release(): "
 171           "context: %p, pthread_self: %p\n",
 172           block, (void*)pthread_self());
 173   asan_register_worker_thread(context->parent_tid, &stack);
 174   // Call the original dispatcher for the block.
 175   context->func(context->block);
 176   asan_free(context, &stack, FROM_MALLOC);
 177 }
 178
 179 }  // namespace __asan
 180
 181 using namespace __asan;
 182
 183 // Wrap |ctxt| and |func| into an asan_block_context_t.
 184 // The caller retains control of the allocated context.
 185 extern "C"
 186 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 187                                          BufferedStackTrace *stack) {
 188   asan_block_context_t *asan_ctxt =
 189       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 190   asan_ctxt->block = ctxt;
 191   asan_ctxt->func = func;
 192   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 193   return asan_ctxt;
 194 }
 195
 196 // Define interceptor for dispatch_*_f function with the three most common
 197 // parameters: dispatch_queue_t, context, dispatch_function_t.
 198 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 199   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 200                                   dispatch_function_t func) {                 \
 201     GET_STACK_TRACE_THREAD;                                                   \
 202     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 203     if (Verbosity() >= 2) {                                     \
 204       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 205              (void*)asan_ctxt, (void*)pthread_self());                        \
 206       PRINT_CURRENT_STACK();                                                  \
 207     }                                                                         \
 208     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 209                               asan_dispatch_call_block_and_release);          \
 210   }
 211
 212 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 213 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 214 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 215
 216 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 217                                     dispatch_queue_t dq, void *ctxt,
 218                                     dispatch_function_t func) {
 219   GET_STACK_TRACE_THREAD;
 220   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 221   if (Verbosity() >= 2) {
 222     Report("dispatch_after_f: %p\n", (void*)asan_ctxt);
 223     PRINT_CURRENT_STACK();
 224   }
 225   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 226                                 asan_dispatch_call_block_and_release);
 227 }
 228
 229 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 230                                           dispatch_queue_t dq, void *ctxt,
 231                                           dispatch_function_t func) {
 232   GET_STACK_TRACE_THREAD;
 233   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 234   if (Verbosity() >= 2) {
 235     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 236            (void*)asan_ctxt, (void*)pthread_self());
 237     PRINT_CURRENT_STACK();
 238   }
 239   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 240                                asan_dispatch_call_block_and_release);
 241 }
 242
 243 #if !defined(MISSING_BLOCKS_SUPPORT)
 244 extern "C" {
 245 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 246 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 247                           void(^work)(void));
 248 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 249                     void(^work)(void));
 250 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 251                                         void(^work)(void));
 252 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 253 dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
 254                                      dispatch_mach_handler_t handler);
 255 }
 256
 257 #define GET_ASAN_BLOCK(work) \
 258   void (^asan_block)(void);  \
 259   int parent_tid = GetCurrentTidOrInvalid(); \
 260   asan_block = ^(void) { \
 261     GET_STACK_TRACE_THREAD; \
 262     asan_register_worker_thread(parent_tid, &stack); \
 263     work(); \
 264   }
 265
 266 INTERCEPTOR(void, dispatch_async,
 267             dispatch_queue_t dq, void(^work)(void)) {
 268   ENABLE_FRAME_POINTER;
 269   GET_ASAN_BLOCK(work);
 270   REAL(dispatch_async)(dq, asan_block);
 271 }
 272
 273 INTERCEPTOR(void, dispatch_group_async,
 274             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 275   ENABLE_FRAME_POINTER;
 276   GET_ASAN_BLOCK(work);
 277   REAL(dispatch_group_async)(dg, dq, asan_block);
 278 }
 279
 280 INTERCEPTOR(void, dispatch_after,
 281             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 282   ENABLE_FRAME_POINTER;
 283   GET_ASAN_BLOCK(work);
 284   REAL(dispatch_after)(when, queue, asan_block);
 285 }
 286
 287 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 288             dispatch_source_t ds, void(^work)(void)) {
 289   if (!work) {
 290     REAL(dispatch_source_set_cancel_handler)(ds, work);
 291     return;
 292   }
 293   ENABLE_FRAME_POINTER;
 294   GET_ASAN_BLOCK(work);
 295   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 296 }
 297
 298 INTERCEPTOR(void, dispatch_source_set_event_handler,
 299             dispatch_source_t ds, void(^work)(void)) {
 300   ENABLE_FRAME_POINTER;
 301   GET_ASAN_BLOCK(work);
 302   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 303 }
 304
 305 INTERCEPTOR(void *, dispatch_mach_create, const char *label,
 306             dispatch_queue_t dq, dispatch_mach_handler_t handler) {
 307   int parent_tid = GetCurrentTidOrInvalid();
 308   return REAL(dispatch_mach_create)(
 309       label, dq,
 310       ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
 311         mach_error_t error) {
 312         GET_STACK_TRACE_THREAD;
 313         asan_register_worker_thread(parent_tid, &stack);
 314         handler(reason, message, error);
 315       });
 316 }
 317
 318 INTERCEPTOR(void *, dispatch_mach_create_f, const char *label,
 319             dispatch_queue_t dq, void *ctxt,
 320             dispatch_mach_handler_function_t handler) {
 321   int parent_tid = GetCurrentTidOrInvalid();
 322   return REAL(dispatch_mach_create)(
 323       label, dq,
 324       ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
 325         mach_error_t error) {
 326         GET_STACK_TRACE_THREAD;
 327         asan_register_worker_thread(parent_tid, &stack);
 328         handler(ctxt, reason, message, error);
 329       });
 330 }
 331
 332 #endif
 333
 334 #endif  // SANITIZER_APPLE