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1 //===-- asan_mac.cc -------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 //
12 // Mac-specific details.
13 //===----------------------------------------------------------------------===//
14 
15 #include "sanitizer_common/sanitizer_platform.h"
16 #if SANITIZER_MAC
17 
18 #include "asan_interceptors.h"
19 #include "asan_internal.h"
20 #include "asan_mapping.h"
21 #include "asan_stack.h"
22 #include "asan_thread.h"
23 #include "sanitizer_common/sanitizer_atomic.h"
24 #include "sanitizer_common/sanitizer_libc.h"
25 #include "sanitizer_common/sanitizer_mac.h"
26 
27 #include <dlfcn.h>
28 #include <fcntl.h>
29 #include <libkern/OSAtomic.h>
30 #include <mach-o/dyld.h>
31 #include <mach-o/getsect.h>
32 #include <mach-o/loader.h>
33 #include <pthread.h>
34 #include <stdlib.h>  // for free()
35 #include <sys/mman.h>
36 #include <sys/resource.h>
37 #include <sys/sysctl.h>
38 #include <sys/ucontext.h>
39 #include <unistd.h>
40 
41 // from <crt_externs.h>, but we don't have that file on iOS
42 extern "C" {
43   extern char ***_NSGetArgv(void);
44   extern char ***_NSGetEnviron(void);
45 }
46 
47 namespace __asan {
48 
InitializePlatformInterceptors()49 void InitializePlatformInterceptors() {}
InitializePlatformExceptionHandlers()50 void InitializePlatformExceptionHandlers() {}
51 
PlatformHasDifferentMemcpyAndMemmove()52 bool PlatformHasDifferentMemcpyAndMemmove() {
53   // On OS X 10.7 memcpy() and memmove() are both resolved
54   // into memmove$VARIANT$sse42.
55   // See also https://github.com/google/sanitizers/issues/34.
56   // TODO(glider): need to check dynamically that memcpy() and memmove() are
57   // actually the same function.
58   return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD;
59 }
60 
61 // No-op. Mac does not support static linkage anyway.
AsanDoesNotSupportStaticLinkage()62 void *AsanDoesNotSupportStaticLinkage() {
63   return 0;
64 }
65 
66 // No-op. Mac does not support static linkage anyway.
AsanCheckDynamicRTPrereqs()67 void AsanCheckDynamicRTPrereqs() {}
68 
69 // No-op. Mac does not support static linkage anyway.
AsanCheckIncompatibleRT()70 void AsanCheckIncompatibleRT() {}
71 
AsanApplyToGlobals(globals_op_fptr op,const void * needle)72 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
73   // Find the Mach-O header for the image containing the needle
74   Dl_info info;
75   int err = dladdr(needle, &info);
76   if (err == 0) return;
77 
78 #if __LP64__
79   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
80 #else
81   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
82 #endif
83 
84   // Look up the __asan_globals section in that image and register its globals
85   unsigned long size = 0;
86   __asan_global *globals = (__asan_global *)getsectiondata(
87       mh,
88       "__DATA", "__asan_globals",
89       &size);
90 
91   if (!globals) return;
92   if (size % sizeof(__asan_global) != 0) return;
93   op(globals, size / sizeof(__asan_global));
94 }
95 
ReadContextStack(void * context,uptr * stack,uptr * ssize)96 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
97   UNIMPLEMENTED();
98 }
99 
100 // Support for the following functions from libdispatch on Mac OS:
101 //   dispatch_async_f()
102 //   dispatch_async()
103 //   dispatch_sync_f()
104 //   dispatch_sync()
105 //   dispatch_after_f()
106 //   dispatch_after()
107 //   dispatch_group_async_f()
108 //   dispatch_group_async()
109 // TODO(glider): libdispatch API contains other functions that we don't support
110 // yet.
111 //
112 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
113 // they can cause jobs to run on a thread different from the current one.
114 // TODO(glider): if so, we need a test for this (otherwise we should remove
115 // them).
116 //
117 // The following functions use dispatch_barrier_async_f() (which isn't a library
118 // function but is exported) and are thus supported:
119 //   dispatch_source_set_cancel_handler_f()
120 //   dispatch_source_set_cancel_handler()
121 //   dispatch_source_set_event_handler_f()
122 //   dispatch_source_set_event_handler()
123 //
124 // The reference manual for Grand Central Dispatch is available at
125 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
126 // The implementation details are at
127 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
128 
129 typedef void* dispatch_group_t;
130 typedef void* dispatch_queue_t;
131 typedef void* dispatch_source_t;
132 typedef u64 dispatch_time_t;
133 typedef void (*dispatch_function_t)(void *block);
134 typedef void* (*worker_t)(void *block);
135 
136 // A wrapper for the ObjC blocks used to support libdispatch.
137 typedef struct {
138   void *block;
139   dispatch_function_t func;
140   u32 parent_tid;
141 } asan_block_context_t;
142 
143 ALWAYS_INLINE
asan_register_worker_thread(int parent_tid,StackTrace * stack)144 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
145   AsanThread *t = GetCurrentThread();
146   if (!t) {
147     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
148                            parent_tid, stack, /* detached */ true);
149     t->Init();
150     asanThreadRegistry().StartThread(t->tid(), 0, 0);
151     SetCurrentThread(t);
152   }
153 }
154 
155 // For use by only those functions that allocated the context via
156 // alloc_asan_context().
157 extern "C"
asan_dispatch_call_block_and_release(void * block)158 void asan_dispatch_call_block_and_release(void *block) {
159   GET_STACK_TRACE_THREAD;
160   asan_block_context_t *context = (asan_block_context_t*)block;
161   VReport(2,
162           "asan_dispatch_call_block_and_release(): "
163           "context: %p, pthread_self: %p\n",
164           block, pthread_self());
165   asan_register_worker_thread(context->parent_tid, &stack);
166   // Call the original dispatcher for the block.
167   context->func(context->block);
168   asan_free(context, &stack, FROM_MALLOC);
169 }
170 
171 }  // namespace __asan
172 
173 using namespace __asan;  // NOLINT
174 
175 // Wrap |ctxt| and |func| into an asan_block_context_t.
176 // The caller retains control of the allocated context.
177 extern "C"
alloc_asan_context(void * ctxt,dispatch_function_t func,BufferedStackTrace * stack)178 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
179                                          BufferedStackTrace *stack) {
180   asan_block_context_t *asan_ctxt =
181       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
182   asan_ctxt->block = ctxt;
183   asan_ctxt->func = func;
184   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
185   return asan_ctxt;
186 }
187 
188 // Define interceptor for dispatch_*_f function with the three most common
189 // parameters: dispatch_queue_t, context, dispatch_function_t.
190 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
191   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
192                                   dispatch_function_t func) {                 \
193     GET_STACK_TRACE_THREAD;                                                   \
194     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
195     if (Verbosity() >= 2) {                                     \
196       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
197              asan_ctxt, pthread_self());                                      \
198       PRINT_CURRENT_STACK();                                                  \
199     }                                                                         \
200     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
201                               asan_dispatch_call_block_and_release);          \
202   }
203 
204 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)205 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
206 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
207 
208 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
209                                     dispatch_queue_t dq, void *ctxt,
210                                     dispatch_function_t func) {
211   GET_STACK_TRACE_THREAD;
212   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
213   if (Verbosity() >= 2) {
214     Report("dispatch_after_f: %p\n", asan_ctxt);
215     PRINT_CURRENT_STACK();
216   }
217   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
218                                 asan_dispatch_call_block_and_release);
219 }
220 
INTERCEPTOR(void,dispatch_group_async_f,dispatch_group_t group,dispatch_queue_t dq,void * ctxt,dispatch_function_t func)221 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
222                                           dispatch_queue_t dq, void *ctxt,
223                                           dispatch_function_t func) {
224   GET_STACK_TRACE_THREAD;
225   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
226   if (Verbosity() >= 2) {
227     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
228            asan_ctxt, pthread_self());
229     PRINT_CURRENT_STACK();
230   }
231   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
232                                asan_dispatch_call_block_and_release);
233 }
234 
235 #if !defined(MISSING_BLOCKS_SUPPORT)
236 extern "C" {
237 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
238 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
239                           void(^work)(void));
240 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
241                     void(^work)(void));
242 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
243                                         void(^work)(void));
244 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
245 }
246 
247 #define GET_ASAN_BLOCK(work) \
248   void (^asan_block)(void);  \
249   int parent_tid = GetCurrentTidOrInvalid(); \
250   asan_block = ^(void) { \
251     GET_STACK_TRACE_THREAD; \
252     asan_register_worker_thread(parent_tid, &stack); \
253     work(); \
254   }
255 
256 INTERCEPTOR(void, dispatch_async,
257             dispatch_queue_t dq, void(^work)(void)) {
258   ENABLE_FRAME_POINTER;
259   GET_ASAN_BLOCK(work);
260   REAL(dispatch_async)(dq, asan_block);
261 }
262 
263 INTERCEPTOR(void, dispatch_group_async,
264             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
265   ENABLE_FRAME_POINTER;
266   GET_ASAN_BLOCK(work);
267   REAL(dispatch_group_async)(dg, dq, asan_block);
268 }
269 
270 INTERCEPTOR(void, dispatch_after,
271             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
272   ENABLE_FRAME_POINTER;
273   GET_ASAN_BLOCK(work);
274   REAL(dispatch_after)(when, queue, asan_block);
275 }
276 
277 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
278             dispatch_source_t ds, void(^work)(void)) {
279   if (!work) {
280     REAL(dispatch_source_set_cancel_handler)(ds, work);
281     return;
282   }
283   ENABLE_FRAME_POINTER;
284   GET_ASAN_BLOCK(work);
285   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
286 }
287 
288 INTERCEPTOR(void, dispatch_source_set_event_handler,
289             dispatch_source_t ds, void(^work)(void)) {
290   ENABLE_FRAME_POINTER;
291   GET_ASAN_BLOCK(work);
292   REAL(dispatch_source_set_event_handler)(ds, asan_block);
293 }
294 #endif
295 
296 #endif  // SANITIZER_MAC
297