1 //===-- asan_mac.cc -------------------------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is a part of AddressSanitizer, an address sanity checker.
9 //
10 // Mac-specific details.
11 //===----------------------------------------------------------------------===//
12
13 #include "sanitizer_common/sanitizer_platform.h"
14 #if SANITIZER_MAC
15
16 #include "asan_interceptors.h"
17 #include "asan_internal.h"
18 #include "asan_mapping.h"
19 #include "asan_stack.h"
20 #include "asan_thread.h"
21 #include "sanitizer_common/sanitizer_atomic.h"
22 #include "sanitizer_common/sanitizer_libc.h"
23 #include "sanitizer_common/sanitizer_mac.h"
24
25 #include <dlfcn.h>
26 #include <fcntl.h>
27 #include <libkern/OSAtomic.h>
28 #include <mach-o/dyld.h>
29 #include <mach-o/getsect.h>
30 #include <mach-o/loader.h>
31 #include <pthread.h>
32 #include <stdlib.h> // for free()
33 #include <sys/mman.h>
34 #include <sys/resource.h>
35 #include <sys/sysctl.h>
36 #include <sys/ucontext.h>
37 #include <unistd.h>
38
39 // from <crt_externs.h>, but we don't have that file on iOS
40 extern "C" {
41 extern char ***_NSGetArgv(void);
42 extern char ***_NSGetEnviron(void);
43 }
44
45 namespace __asan {
46
InitializePlatformInterceptors()47 void InitializePlatformInterceptors() {}
InitializePlatformExceptionHandlers()48 void InitializePlatformExceptionHandlers() {}
IsSystemHeapAddress(uptr addr)49 bool IsSystemHeapAddress (uptr addr) { return false; }
50
51 // No-op. Mac does not support static linkage anyway.
AsanDoesNotSupportStaticLinkage()52 void *AsanDoesNotSupportStaticLinkage() {
53 return 0;
54 }
55
FindDynamicShadowStart()56 uptr FindDynamicShadowStart() {
57 uptr granularity = GetMmapGranularity();
58 uptr alignment = 8 * granularity;
59 uptr left_padding = granularity;
60 uptr space_size = kHighShadowEnd + left_padding;
61
62 uptr largest_gap_found = 0;
63 uptr max_occupied_addr = 0;
64 VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
65 uptr shadow_start =
66 FindAvailableMemoryRange(space_size, alignment, granularity,
67 &largest_gap_found, &max_occupied_addr);
68 // If the shadow doesn't fit, restrict the address space to make it fit.
69 if (shadow_start == 0) {
70 VReport(
71 2,
72 "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
73 largest_gap_found, max_occupied_addr);
74 uptr new_max_vm = RoundDownTo(largest_gap_found << SHADOW_SCALE, alignment);
75 if (new_max_vm < max_occupied_addr) {
76 Report("Unable to find a memory range for dynamic shadow.\n");
77 Report(
78 "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
79 "new_max_vm = %p\n",
80 space_size, largest_gap_found, max_occupied_addr, new_max_vm);
81 CHECK(0 && "cannot place shadow");
82 }
83 RestrictMemoryToMaxAddress(new_max_vm);
84 kHighMemEnd = new_max_vm - 1;
85 space_size = kHighShadowEnd + left_padding;
86 VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
87 shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
88 nullptr, nullptr);
89 if (shadow_start == 0) {
90 Report("Unable to find a memory range after restricting VM.\n");
91 CHECK(0 && "cannot place shadow after restricting vm");
92 }
93 }
94 CHECK_NE((uptr)0, shadow_start);
95 CHECK(IsAligned(shadow_start, alignment));
96 return shadow_start;
97 }
98
99 // No-op. Mac does not support static linkage anyway.
AsanCheckDynamicRTPrereqs()100 void AsanCheckDynamicRTPrereqs() {}
101
102 // No-op. Mac does not support static linkage anyway.
AsanCheckIncompatibleRT()103 void AsanCheckIncompatibleRT() {}
104
AsanApplyToGlobals(globals_op_fptr op,const void * needle)105 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
106 // Find the Mach-O header for the image containing the needle
107 Dl_info info;
108 int err = dladdr(needle, &info);
109 if (err == 0) return;
110
111 #if __LP64__
112 const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
113 #else
114 const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
115 #endif
116
117 // Look up the __asan_globals section in that image and register its globals
118 unsigned long size = 0;
119 __asan_global *globals = (__asan_global *)getsectiondata(
120 mh,
121 "__DATA", "__asan_globals",
122 &size);
123
124 if (!globals) return;
125 if (size % sizeof(__asan_global) != 0) return;
126 op(globals, size / sizeof(__asan_global));
127 }
128
ReadContextStack(void * context,uptr * stack,uptr * ssize)129 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
130 UNIMPLEMENTED();
131 }
132
133 // Support for the following functions from libdispatch on Mac OS:
134 // dispatch_async_f()
135 // dispatch_async()
136 // dispatch_sync_f()
137 // dispatch_sync()
138 // dispatch_after_f()
139 // dispatch_after()
140 // dispatch_group_async_f()
141 // dispatch_group_async()
142 // TODO(glider): libdispatch API contains other functions that we don't support
143 // yet.
144 //
145 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
146 // they can cause jobs to run on a thread different from the current one.
147 // TODO(glider): if so, we need a test for this (otherwise we should remove
148 // them).
149 //
150 // The following functions use dispatch_barrier_async_f() (which isn't a library
151 // function but is exported) and are thus supported:
152 // dispatch_source_set_cancel_handler_f()
153 // dispatch_source_set_cancel_handler()
154 // dispatch_source_set_event_handler_f()
155 // dispatch_source_set_event_handler()
156 //
157 // The reference manual for Grand Central Dispatch is available at
158 // http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
159 // The implementation details are at
160 // http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
161
162 typedef void* dispatch_group_t;
163 typedef void* dispatch_queue_t;
164 typedef void* dispatch_source_t;
165 typedef u64 dispatch_time_t;
166 typedef void (*dispatch_function_t)(void *block);
167 typedef void* (*worker_t)(void *block);
168
169 // A wrapper for the ObjC blocks used to support libdispatch.
170 typedef struct {
171 void *block;
172 dispatch_function_t func;
173 u32 parent_tid;
174 } asan_block_context_t;
175
176 ALWAYS_INLINE
asan_register_worker_thread(int parent_tid,StackTrace * stack)177 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
178 AsanThread *t = GetCurrentThread();
179 if (!t) {
180 t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
181 parent_tid, stack, /* detached */ true);
182 t->Init();
183 asanThreadRegistry().StartThread(t->tid(), GetTid(),
184 /* workerthread */ true, 0);
185 SetCurrentThread(t);
186 }
187 }
188
189 // For use by only those functions that allocated the context via
190 // alloc_asan_context().
191 extern "C"
asan_dispatch_call_block_and_release(void * block)192 void asan_dispatch_call_block_and_release(void *block) {
193 GET_STACK_TRACE_THREAD;
194 asan_block_context_t *context = (asan_block_context_t*)block;
195 VReport(2,
196 "asan_dispatch_call_block_and_release(): "
197 "context: %p, pthread_self: %p\n",
198 block, pthread_self());
199 asan_register_worker_thread(context->parent_tid, &stack);
200 // Call the original dispatcher for the block.
201 context->func(context->block);
202 asan_free(context, &stack, FROM_MALLOC);
203 }
204
205 } // namespace __asan
206
207 using namespace __asan; // NOLINT
208
209 // Wrap |ctxt| and |func| into an asan_block_context_t.
210 // The caller retains control of the allocated context.
211 extern "C"
alloc_asan_context(void * ctxt,dispatch_function_t func,BufferedStackTrace * stack)212 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
213 BufferedStackTrace *stack) {
214 asan_block_context_t *asan_ctxt =
215 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
216 asan_ctxt->block = ctxt;
217 asan_ctxt->func = func;
218 asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
219 return asan_ctxt;
220 }
221
222 // Define interceptor for dispatch_*_f function with the three most common
223 // parameters: dispatch_queue_t, context, dispatch_function_t.
224 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \
225 INTERCEPTOR(void, dispatch_x_f, 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_x_f "(): context: %p, pthread_self: %p\n", \
231 asan_ctxt, pthread_self()); \
232 PRINT_CURRENT_STACK(); \
233 } \
234 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \
235 asan_dispatch_call_block_and_release); \
236 }
237
238 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)239 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
240 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
241
242 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
243 dispatch_queue_t dq, void *ctxt,
244 dispatch_function_t func) {
245 GET_STACK_TRACE_THREAD;
246 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
247 if (Verbosity() >= 2) {
248 Report("dispatch_after_f: %p\n", asan_ctxt);
249 PRINT_CURRENT_STACK();
250 }
251 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
252 asan_dispatch_call_block_and_release);
253 }
254
INTERCEPTOR(void,dispatch_group_async_f,dispatch_group_t group,dispatch_queue_t dq,void * ctxt,dispatch_function_t func)255 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
256 dispatch_queue_t dq, void *ctxt,
257 dispatch_function_t func) {
258 GET_STACK_TRACE_THREAD;
259 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
260 if (Verbosity() >= 2) {
261 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
262 asan_ctxt, pthread_self());
263 PRINT_CURRENT_STACK();
264 }
265 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
266 asan_dispatch_call_block_and_release);
267 }
268
269 #if !defined(MISSING_BLOCKS_SUPPORT)
270 extern "C" {
271 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
272 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
273 void(^work)(void));
274 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
275 void(^work)(void));
276 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
277 void(^work)(void));
278 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
279 }
280
281 #define GET_ASAN_BLOCK(work) \
282 void (^asan_block)(void); \
283 int parent_tid = GetCurrentTidOrInvalid(); \
284 asan_block = ^(void) { \
285 GET_STACK_TRACE_THREAD; \
286 asan_register_worker_thread(parent_tid, &stack); \
287 work(); \
288 }
289
290 INTERCEPTOR(void, dispatch_async,
291 dispatch_queue_t dq, void(^work)(void)) {
292 ENABLE_FRAME_POINTER;
293 GET_ASAN_BLOCK(work);
294 REAL(dispatch_async)(dq, asan_block);
295 }
296
297 INTERCEPTOR(void, dispatch_group_async,
298 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
299 ENABLE_FRAME_POINTER;
300 GET_ASAN_BLOCK(work);
301 REAL(dispatch_group_async)(dg, dq, asan_block);
302 }
303
304 INTERCEPTOR(void, dispatch_after,
305 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
306 ENABLE_FRAME_POINTER;
307 GET_ASAN_BLOCK(work);
308 REAL(dispatch_after)(when, queue, asan_block);
309 }
310
311 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
312 dispatch_source_t ds, void(^work)(void)) {
313 if (!work) {
314 REAL(dispatch_source_set_cancel_handler)(ds, work);
315 return;
316 }
317 ENABLE_FRAME_POINTER;
318 GET_ASAN_BLOCK(work);
319 REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
320 }
321
322 INTERCEPTOR(void, dispatch_source_set_event_handler,
323 dispatch_source_t ds, void(^work)(void)) {
324 ENABLE_FRAME_POINTER;
325 GET_ASAN_BLOCK(work);
326 REAL(dispatch_source_set_event_handler)(ds, asan_block);
327 }
328 #endif
329
330 #endif // SANITIZER_MAC
331