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