compiler-rt/lib/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 typedef unsigned long dispatch_mach_reason;
 134 typedef void *dispatch_mach_msg_t;
 135 typedef int mach_error_t;
 136 typedef void *dispatch_mach_t;
 137
 138 typedef void (*dispatch_mach_handler_function_t)(void *context,
 139                                                  dispatch_mach_reason reason,
 140                                                  dispatch_mach_msg_t message,
 141                                                  mach_error_t error);
 142 typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
 143                                         dispatch_mach_msg_t message,
 144                                         mach_error_t error);
 145
 146 // A wrapper for the ObjC blocks used to support libdispatch.
 147 typedef struct {
 148   void *block;
 149   dispatch_function_t func;
 150   u32 parent_tid;
 151 } asan_block_context_t;
 152
 153 ALWAYS_INLINE
 154 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 155   AsanThread *t = GetCurrentThread();
 156   if (!t) {
 157     t = AsanThread::Create(parent_tid, stack, /* detached */ true);
 158     t->Init();
 159     asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
 160                                      nullptr);
 161     SetCurrentThread(t);
 162   }
 163 }
 164
 165 // For use by only those functions that allocated the context via
 166 // alloc_asan_context().
 167 extern "C"
 168 void asan_dispatch_call_block_and_release(void *block) {
 169   GET_STACK_TRACE_THREAD;
 170   asan_block_context_t *context = (asan_block_context_t*)block;
 171   VReport(2,
 172           "asan_dispatch_call_block_and_release(): "
 173           "context: %p, pthread_self: %p\n",
 174           block, (void*)pthread_self());
 175   asan_register_worker_thread(context->parent_tid, &stack);
 176   // Call the original dispatcher for the block.
 177   context->func(context->block);
 178   asan_free(context, &stack, FROM_MALLOC);
 179 }
 180
 181 }  // namespace __asan
 182
 183 using namespace __asan;
 184
 185 // Wrap |ctxt| and |func| into an asan_block_context_t.
 186 // The caller retains control of the allocated context.
 187 extern "C"
 188 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 189                                          BufferedStackTrace *stack) {
 190   asan_block_context_t *asan_ctxt =
 191       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 192   asan_ctxt->block = ctxt;
 193   asan_ctxt->func = func;
 194   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 195   return asan_ctxt;
 196 }
 197
 198 // Define interceptor for dispatch_*_f function with the three most common
 199 // parameters: dispatch_queue_t, context, dispatch_function_t.
 200 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 201   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 202                                   dispatch_function_t func) {                 \
 203     GET_STACK_TRACE_THREAD;                                                   \
 204     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 205     if (Verbosity() >= 2) {                                     \
 206       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 207              (void*)asan_ctxt, (void*)pthread_self());                        \
 208       PRINT_CURRENT_STACK();                                                  \
 209     }                                                                         \
 210     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 211                               asan_dispatch_call_block_and_release);          \
 212   }
 213
 214 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 215 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 216 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 217
 218 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 219                                     dispatch_queue_t dq, void *ctxt,
 220                                     dispatch_function_t func) {
 221   GET_STACK_TRACE_THREAD;
 222   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 223   if (Verbosity() >= 2) {
 224     Report("dispatch_after_f: %p\n", (void*)asan_ctxt);
 225     PRINT_CURRENT_STACK();
 226   }
 227   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 228                                 asan_dispatch_call_block_and_release);
 229 }
 230
 231 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 232                                           dispatch_queue_t dq, void *ctxt,
 233                                           dispatch_function_t func) {
 234   GET_STACK_TRACE_THREAD;
 235   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 236   if (Verbosity() >= 2) {
 237     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 238            (void*)asan_ctxt, (void*)pthread_self());
 239     PRINT_CURRENT_STACK();
 240   }
 241   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 242                                asan_dispatch_call_block_and_release);
 243 }
 244
 245 #if !defined(MISSING_BLOCKS_SUPPORT)
 246 extern "C" {
 247 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 248 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 249                           void(^work)(void));
 250 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 251                     void(^work)(void));
 252 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 253                                         void(^work)(void));
 254 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 255 dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
 256                                      dispatch_mach_handler_t handler);
 257 }
 258
 259 #define GET_ASAN_BLOCK(work) \
 260   void (^asan_block)(void);  \
 261   int parent_tid = GetCurrentTidOrInvalid(); \
 262   asan_block = ^(void) { \
 263     GET_STACK_TRACE_THREAD; \
 264     asan_register_worker_thread(parent_tid, &stack); \
 265     work(); \
 266   }
 267
 268 INTERCEPTOR(void, dispatch_async,
 269             dispatch_queue_t dq, void(^work)(void)) {
 270   ENABLE_FRAME_POINTER;
 271   GET_ASAN_BLOCK(work);
 272   REAL(dispatch_async)(dq, asan_block);
 273 }
 274
 275 INTERCEPTOR(void, dispatch_group_async,
 276             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 277   ENABLE_FRAME_POINTER;
 278   GET_ASAN_BLOCK(work);
 279   REAL(dispatch_group_async)(dg, dq, asan_block);
 280 }
 281
 282 INTERCEPTOR(void, dispatch_after,
 283             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 284   ENABLE_FRAME_POINTER;
 285   GET_ASAN_BLOCK(work);
 286   REAL(dispatch_after)(when, queue, asan_block);
 287 }
 288
 289 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 290             dispatch_source_t ds, void(^work)(void)) {
 291   if (!work) {
 292     REAL(dispatch_source_set_cancel_handler)(ds, work);
 293     return;
 294   }
 295   ENABLE_FRAME_POINTER;
 296   GET_ASAN_BLOCK(work);
 297   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 298 }
 299
 300 INTERCEPTOR(void, dispatch_source_set_event_handler,
 301             dispatch_source_t ds, void(^work)(void)) {
 302   ENABLE_FRAME_POINTER;
 303   GET_ASAN_BLOCK(work);
 304   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 305 }
 306
 307 INTERCEPTOR(void *, dispatch_mach_create, const char *label,
 308             dispatch_queue_t dq, dispatch_mach_handler_t handler) {
 309   int parent_tid = GetCurrentTidOrInvalid();
 310   return REAL(dispatch_mach_create)(
 311       label, dq,
 312       ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
 313         mach_error_t error) {
 314         GET_STACK_TRACE_THREAD;
 315         asan_register_worker_thread(parent_tid, &stack);
 316         handler(reason, message, error);
 317       });
 318 }
 319
 320 INTERCEPTOR(void *, dispatch_mach_create_f, const char *label,
 321             dispatch_queue_t dq, void *ctxt,
 322             dispatch_mach_handler_function_t handler) {
 323   int parent_tid = GetCurrentTidOrInvalid();
 324   return REAL(dispatch_mach_create)(
 325       label, dq,
 326       ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
 327         mach_error_t error) {
 328         GET_STACK_TRACE_THREAD;
 329         asan_register_worker_thread(parent_tid, &stack);
 330         handler(ctxt, reason, message, error);
 331       });
 332 }
 333
 334 #endif
 335
 336 #endif  // SANITIZER_APPLE