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 41extern "C" { 42 extern char ***_NSGetArgv(void); 43 extern char ***_NSGetEnviron(void); 44} 45 46namespace __asan { 47 48void InitializePlatformInterceptors() {} 49void InitializePlatformExceptionHandlers() {} 50bool IsSystemHeapAddress (uptr addr) { return false; } 51 52// No-op. Mac does not support static linkage anyway. 53void *AsanDoesNotSupportStaticLinkage() { 54 return 0; 55} 56 57uptr 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. 63void AsanCheckDynamicRTPrereqs() {} 64 65// No-op. Mac does not support static linkage anyway. 66void AsanCheckIncompatibleRT() {} 67 68void 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 92void 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 127typedef void* dispatch_group_t; 128typedef void* dispatch_queue_t; 129typedef void* dispatch_source_t; 130typedef u64 dispatch_time_t; 131typedef void (*dispatch_function_t)(void *block); 132typedef void* (*worker_t)(void *block); 133typedef unsigned long dispatch_mach_reason; 134typedef void *dispatch_mach_msg_t; 135typedef int mach_error_t; 136typedef void *dispatch_mach_t; 137 138typedef 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# if !defined(MISSING_BLOCKS_SUPPORT) 143typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason, 144 dispatch_mach_msg_t message, 145 mach_error_t error); 146# endif 147 148// A wrapper for the ObjC blocks used to support libdispatch. 149typedef struct { 150 void *block; 151 dispatch_function_t func; 152 u32 parent_tid; 153} asan_block_context_t; 154 155ALWAYS_INLINE 156void asan_register_worker_thread(int parent_tid, StackTrace *stack) { 157 AsanThread *t = GetCurrentThread(); 158 if (!t) { 159 t = AsanThread::Create(parent_tid, stack, /* detached */ true); 160 t->Init(); 161 asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker, 162 nullptr); 163 SetCurrentThread(t); 164 } 165} 166 167// For use by only those functions that allocated the context via 168// alloc_asan_context(). 169extern "C" 170void asan_dispatch_call_block_and_release(void *block) { 171 GET_STACK_TRACE_THREAD; 172 asan_block_context_t *context = (asan_block_context_t*)block; 173 VReport(2, 174 "asan_dispatch_call_block_and_release(): " 175 "context: %p, pthread_self: %p\n", 176 block, (void*)pthread_self()); 177 asan_register_worker_thread(context->parent_tid, &stack); 178 // Call the original dispatcher for the block. 179 context->func(context->block); 180 asan_free(context, &stack, FROM_MALLOC); 181} 182 183} // namespace __asan 184 185using namespace __asan; 186 187// Wrap |ctxt| and |func| into an asan_block_context_t. 188// The caller retains control of the allocated context. 189extern "C" 190asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func, 191 BufferedStackTrace *stack) { 192 asan_block_context_t *asan_ctxt = 193 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack); 194 asan_ctxt->block = ctxt; 195 asan_ctxt->func = func; 196 asan_ctxt->parent_tid = GetCurrentTidOrInvalid(); 197 return asan_ctxt; 198} 199 200// Define interceptor for dispatch_*_f function with the three most common 201// parameters: dispatch_queue_t, context, dispatch_function_t. 202#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \ 203 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \ 204 dispatch_function_t func) { \ 205 GET_STACK_TRACE_THREAD; \ 206 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \ 207 if (Verbosity() >= 2) { \ 208 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \ 209 (void*)asan_ctxt, (void*)pthread_self()); \ 210 PRINT_CURRENT_STACK(); \ 211 } \ 212 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \ 213 asan_dispatch_call_block_and_release); \ 214 } 215 216INTERCEPT_DISPATCH_X_F_3(dispatch_async_f) 217INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f) 218INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f) 219 220INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, 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_after_f: %p\n", (void*)asan_ctxt); 227 PRINT_CURRENT_STACK(); 228 } 229 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt, 230 asan_dispatch_call_block_and_release); 231} 232 233INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group, 234 dispatch_queue_t dq, void *ctxt, 235 dispatch_function_t func) { 236 GET_STACK_TRACE_THREAD; 237 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); 238 if (Verbosity() >= 2) { 239 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n", 240 (void*)asan_ctxt, (void*)pthread_self()); 241 PRINT_CURRENT_STACK(); 242 } 243 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt, 244 asan_dispatch_call_block_and_release); 245} 246 247#if !defined(MISSING_BLOCKS_SUPPORT) 248extern "C" { 249void dispatch_async(dispatch_queue_t dq, void(^work)(void)); 250void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq, 251 void(^work)(void)); 252void dispatch_after(dispatch_time_t when, dispatch_queue_t queue, 253 void(^work)(void)); 254void dispatch_source_set_cancel_handler(dispatch_source_t ds, 255 void(^work)(void)); 256void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void)); 257dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue, 258 dispatch_mach_handler_t handler); 259} 260 261#define GET_ASAN_BLOCK(work) \ 262 void (^asan_block)(void); \ 263 int parent_tid = GetCurrentTidOrInvalid(); \ 264 asan_block = ^(void) { \ 265 GET_STACK_TRACE_THREAD; \ 266 asan_register_worker_thread(parent_tid, &stack); \ 267 work(); \ 268 } 269 270INTERCEPTOR(void, dispatch_async, 271 dispatch_queue_t dq, void(^work)(void)) { 272 ENABLE_FRAME_POINTER; 273 GET_ASAN_BLOCK(work); 274 REAL(dispatch_async)(dq, asan_block); 275} 276 277INTERCEPTOR(void, dispatch_group_async, 278 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) { 279 ENABLE_FRAME_POINTER; 280 GET_ASAN_BLOCK(work); 281 REAL(dispatch_group_async)(dg, dq, asan_block); 282} 283 284INTERCEPTOR(void, dispatch_after, 285 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) { 286 ENABLE_FRAME_POINTER; 287 GET_ASAN_BLOCK(work); 288 REAL(dispatch_after)(when, queue, asan_block); 289} 290 291INTERCEPTOR(void, dispatch_source_set_cancel_handler, 292 dispatch_source_t ds, void(^work)(void)) { 293 if (!work) { 294 REAL(dispatch_source_set_cancel_handler)(ds, work); 295 return; 296 } 297 ENABLE_FRAME_POINTER; 298 GET_ASAN_BLOCK(work); 299 REAL(dispatch_source_set_cancel_handler)(ds, asan_block); 300} 301 302INTERCEPTOR(void, dispatch_source_set_event_handler, 303 dispatch_source_t ds, void(^work)(void)) { 304 ENABLE_FRAME_POINTER; 305 GET_ASAN_BLOCK(work); 306 REAL(dispatch_source_set_event_handler)(ds, asan_block); 307} 308 309INTERCEPTOR(void *, dispatch_mach_create, const char *label, 310 dispatch_queue_t dq, dispatch_mach_handler_t handler) { 311 int parent_tid = GetCurrentTidOrInvalid(); 312 return REAL(dispatch_mach_create)( 313 label, dq, 314 ^(dispatch_mach_reason reason, dispatch_mach_msg_t message, 315 mach_error_t error) { 316 GET_STACK_TRACE_THREAD; 317 asan_register_worker_thread(parent_tid, &stack); 318 handler(reason, message, error); 319 }); 320} 321 322INTERCEPTOR(void *, dispatch_mach_create_f, const char *label, 323 dispatch_queue_t dq, void *ctxt, 324 dispatch_mach_handler_function_t handler) { 325 int parent_tid = GetCurrentTidOrInvalid(); 326 return REAL(dispatch_mach_create)( 327 label, dq, 328 ^(dispatch_mach_reason reason, dispatch_mach_msg_t message, 329 mach_error_t error) { 330 GET_STACK_TRACE_THREAD; 331 asan_register_worker_thread(parent_tid, &stack); 332 handler(ctxt, reason, message, error); 333 }); 334} 335 336#endif 337 338#endif // SANITIZER_APPLE 339