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 296