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
InitializePlatformInterceptors()48 void InitializePlatformInterceptors() {}
InitializePlatformExceptionHandlers()49 void InitializePlatformExceptionHandlers() {}
IsSystemHeapAddress(uptr addr)50 bool IsSystemHeapAddress (uptr addr) { return false; }
51
52 // No-op. Mac does not support static linkage anyway.
AsanDoesNotSupportStaticLinkage()53 void *AsanDoesNotSupportStaticLinkage() {
54 return 0;
55 }
56
FindDynamicShadowStart()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.
AsanCheckDynamicRTPrereqs()63 void AsanCheckDynamicRTPrereqs() {}
64
65 // No-op. Mac does not support static linkage anyway.
AsanCheckIncompatibleRT()66 void AsanCheckIncompatibleRT() {}
67
AsanApplyToGlobals(globals_op_fptr op,const void * needle)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
FlushUnneededASanShadowMemory(uptr p,uptr size)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 typedef unsigned long dispatch_mach_reason;
134 typedef void *dispatch_mach_msg_t;
135 typedef int mach_error_t;
136 typedef void *dispatch_mach_t;
137
138 typedef void (*dispatch_mach_handler_function_t)(void *context,
139 dispatch_mach_reason reason,
140 dispatch_mach_msg_t message,
141 mach_error_t error);
142 # if !defined(MISSING_BLOCKS_SUPPORT)
143 typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
144 dispatch_mach_msg_t message,
145 mach_error_t error);
146 # endif
147
148 // A wrapper for the ObjC blocks used to support libdispatch.
149 typedef struct {
150 void *block;
151 dispatch_function_t func;
152 u32 parent_tid;
153 } asan_block_context_t;
154
155 ALWAYS_INLINE
asan_register_worker_thread(int parent_tid,StackTrace * stack)156 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
157 AsanThread *t = GetCurrentThread();
158 if (!t) {
159 t = AsanThread::Create(parent_tid, stack, /* detached */ true);
160 t->Init();
161 asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
162 nullptr);
163 SetCurrentThread(t);
164 }
165 }
166
167 // For use by only those functions that allocated the context via
168 // alloc_asan_context().
169 extern "C"
asan_dispatch_call_block_and_release(void * block)170 void asan_dispatch_call_block_and_release(void *block) {
171 GET_STACK_TRACE_THREAD;
172 asan_block_context_t *context = (asan_block_context_t*)block;
173 VReport(2,
174 "asan_dispatch_call_block_and_release(): "
175 "context: %p, pthread_self: %p\n",
176 block, (void*)pthread_self());
177 asan_register_worker_thread(context->parent_tid, &stack);
178 // Call the original dispatcher for the block.
179 context->func(context->block);
180 asan_free(context, &stack, FROM_MALLOC);
181 }
182
183 } // namespace __asan
184
185 using namespace __asan;
186
187 // Wrap |ctxt| and |func| into an asan_block_context_t.
188 // The caller retains control of the allocated context.
189 extern "C"
alloc_asan_context(void * ctxt,dispatch_function_t func,BufferedStackTrace * stack)190 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
191 BufferedStackTrace *stack) {
192 asan_block_context_t *asan_ctxt =
193 (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
194 asan_ctxt->block = ctxt;
195 asan_ctxt->func = func;
196 asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
197 return asan_ctxt;
198 }
199
200 // Define interceptor for dispatch_*_f function with the three most common
201 // parameters: dispatch_queue_t, context, dispatch_function_t.
202 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \
203 INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \
204 dispatch_function_t func) { \
205 GET_STACK_TRACE_THREAD; \
206 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
207 if (Verbosity() >= 2) { \
208 Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \
209 (void*)asan_ctxt, (void*)pthread_self()); \
210 PRINT_CURRENT_STACK(); \
211 } \
212 return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \
213 asan_dispatch_call_block_and_release); \
214 }
215
216 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)217 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
218 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
219
220 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
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_after_f: %p\n", (void*)asan_ctxt);
227 PRINT_CURRENT_STACK();
228 }
229 return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
230 asan_dispatch_call_block_and_release);
231 }
232
INTERCEPTOR(void,dispatch_group_async_f,dispatch_group_t group,dispatch_queue_t dq,void * ctxt,dispatch_function_t func)233 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
234 dispatch_queue_t dq, void *ctxt,
235 dispatch_function_t func) {
236 GET_STACK_TRACE_THREAD;
237 asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
238 if (Verbosity() >= 2) {
239 Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
240 (void*)asan_ctxt, (void*)pthread_self());
241 PRINT_CURRENT_STACK();
242 }
243 REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
244 asan_dispatch_call_block_and_release);
245 }
246
247 #if !defined(MISSING_BLOCKS_SUPPORT)
248 extern "C" {
249 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
250 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
251 void(^work)(void));
252 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
253 void(^work)(void));
254 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
255 void(^work)(void));
256 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
257 dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
258 dispatch_mach_handler_t handler);
259 }
260
261 #define GET_ASAN_BLOCK(work) \
262 void (^asan_block)(void); \
263 int parent_tid = GetCurrentTidOrInvalid(); \
264 asan_block = ^(void) { \
265 GET_STACK_TRACE_THREAD; \
266 asan_register_worker_thread(parent_tid, &stack); \
267 work(); \
268 }
269
270 INTERCEPTOR(void, dispatch_async,
271 dispatch_queue_t dq, void(^work)(void)) {
272 ENABLE_FRAME_POINTER;
273 GET_ASAN_BLOCK(work);
274 REAL(dispatch_async)(dq, asan_block);
275 }
276
277 INTERCEPTOR(void, dispatch_group_async,
278 dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
279 ENABLE_FRAME_POINTER;
280 GET_ASAN_BLOCK(work);
281 REAL(dispatch_group_async)(dg, dq, asan_block);
282 }
283
284 INTERCEPTOR(void, dispatch_after,
285 dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
286 ENABLE_FRAME_POINTER;
287 GET_ASAN_BLOCK(work);
288 REAL(dispatch_after)(when, queue, asan_block);
289 }
290
291 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
292 dispatch_source_t ds, void(^work)(void)) {
293 if (!work) {
294 REAL(dispatch_source_set_cancel_handler)(ds, work);
295 return;
296 }
297 ENABLE_FRAME_POINTER;
298 GET_ASAN_BLOCK(work);
299 REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
300 }
301
302 INTERCEPTOR(void, dispatch_source_set_event_handler,
303 dispatch_source_t ds, void(^work)(void)) {
304 ENABLE_FRAME_POINTER;
305 GET_ASAN_BLOCK(work);
306 REAL(dispatch_source_set_event_handler)(ds, asan_block);
307 }
308
INTERCEPTOR(void *,dispatch_mach_create,const char * label,dispatch_queue_t dq,dispatch_mach_handler_t handler)309 INTERCEPTOR(void *, dispatch_mach_create, const char *label,
310 dispatch_queue_t dq, dispatch_mach_handler_t handler) {
311 int parent_tid = GetCurrentTidOrInvalid();
312 return REAL(dispatch_mach_create)(
313 label, dq,
314 ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
315 mach_error_t error) {
316 GET_STACK_TRACE_THREAD;
317 asan_register_worker_thread(parent_tid, &stack);
318 handler(reason, message, error);
319 });
320 }
321
INTERCEPTOR(void *,dispatch_mach_create_f,const char * label,dispatch_queue_t dq,void * ctxt,dispatch_mach_handler_function_t handler)322 INTERCEPTOR(void *, dispatch_mach_create_f, const char *label,
323 dispatch_queue_t dq, void *ctxt,
324 dispatch_mach_handler_function_t handler) {
325 int parent_tid = GetCurrentTidOrInvalid();
326 return REAL(dispatch_mach_create)(
327 label, dq,
328 ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
329 mach_error_t error) {
330 GET_STACK_TRACE_THREAD;
331 asan_register_worker_thread(parent_tid, &stack);
332 handler(ctxt, reason, message, error);
333 });
334 }
335
336 #endif
337
338 #endif // SANITIZER_APPLE
339