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