1 /*
2 * Copyright (C) 2007 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include "linker.h"
30 #include "linker_cfi.h"
31 #include "linker_globals.h"
32 #include "linker_dlwarning.h"
33
34 #include <pthread.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <android/api-level.h>
39
40 #include <bionic/pthread_internal.h>
41 #include "private/bionic_tls.h"
42 #include "private/ScopedPthreadMutexLocker.h"
43
44 static pthread_mutex_t g_dl_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
45
__bionic_set_dlerror(char * new_value)46 static char* __bionic_set_dlerror(char* new_value) {
47 char** dlerror_slot = &reinterpret_cast<char**>(__get_tls())[TLS_SLOT_DLERROR];
48
49 char* old_value = *dlerror_slot;
50 *dlerror_slot = new_value;
51 LD_LOG(kLogErrors, "%s\n", new_value);
52 return old_value;
53 }
54
__bionic_format_dlerror(const char * msg,const char * detail)55 static void __bionic_format_dlerror(const char* msg, const char* detail) {
56 char* buffer = __get_thread()->dlerror_buffer;
57 strlcpy(buffer, msg, __BIONIC_DLERROR_BUFFER_SIZE);
58 if (detail != nullptr) {
59 strlcat(buffer, ": ", __BIONIC_DLERROR_BUFFER_SIZE);
60 strlcat(buffer, detail, __BIONIC_DLERROR_BUFFER_SIZE);
61 }
62
63 __bionic_set_dlerror(buffer);
64 }
65
__dlerror()66 char* __dlerror() {
67 char* old_value = __bionic_set_dlerror(nullptr);
68 return old_value;
69 }
70
__android_get_LD_LIBRARY_PATH(char * buffer,size_t buffer_size)71 void __android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) {
72 ScopedPthreadMutexLocker locker(&g_dl_mutex);
73 do_android_get_LD_LIBRARY_PATH(buffer, buffer_size);
74 }
75
__android_update_LD_LIBRARY_PATH(const char * ld_library_path)76 void __android_update_LD_LIBRARY_PATH(const char* ld_library_path) {
77 ScopedPthreadMutexLocker locker(&g_dl_mutex);
78 do_android_update_LD_LIBRARY_PATH(ld_library_path);
79 }
80
dlopen_ext(const char * filename,int flags,const android_dlextinfo * extinfo,const void * caller_addr)81 static void* dlopen_ext(const char* filename,
82 int flags,
83 const android_dlextinfo* extinfo,
84 const void* caller_addr) {
85 ScopedPthreadMutexLocker locker(&g_dl_mutex);
86 g_linker_logger.ResetState();
87 void* result = do_dlopen(filename, flags, extinfo, caller_addr);
88 if (result == nullptr) {
89 __bionic_format_dlerror("dlopen failed", linker_get_error_buffer());
90 return nullptr;
91 }
92 return result;
93 }
94
__android_dlopen_ext(const char * filename,int flags,const android_dlextinfo * extinfo,const void * caller_addr)95 void* __android_dlopen_ext(const char* filename,
96 int flags,
97 const android_dlextinfo* extinfo,
98 const void* caller_addr) {
99 return dlopen_ext(filename, flags, extinfo, caller_addr);
100 }
101
__dlopen(const char * filename,int flags,const void * caller_addr)102 void* __dlopen(const char* filename, int flags, const void* caller_addr) {
103 return dlopen_ext(filename, flags, nullptr, caller_addr);
104 }
105
dlsym_impl(void * handle,const char * symbol,const char * version,const void * caller_addr)106 void* dlsym_impl(void* handle, const char* symbol, const char* version, const void* caller_addr) {
107 ScopedPthreadMutexLocker locker(&g_dl_mutex);
108 g_linker_logger.ResetState();
109 void* result;
110 if (!do_dlsym(handle, symbol, version, caller_addr, &result)) {
111 __bionic_format_dlerror(linker_get_error_buffer(), nullptr);
112 return nullptr;
113 }
114
115 return result;
116 }
117
__dlsym(void * handle,const char * symbol,const void * caller_addr)118 void* __dlsym(void* handle, const char* symbol, const void* caller_addr) {
119 return dlsym_impl(handle, symbol, nullptr, caller_addr);
120 }
121
__dlvsym(void * handle,const char * symbol,const char * version,const void * caller_addr)122 void* __dlvsym(void* handle, const char* symbol, const char* version, const void* caller_addr) {
123 return dlsym_impl(handle, symbol, version, caller_addr);
124 }
125
__dladdr(const void * addr,Dl_info * info)126 int __dladdr(const void* addr, Dl_info* info) {
127 ScopedPthreadMutexLocker locker(&g_dl_mutex);
128 return do_dladdr(addr, info);
129 }
130
__dlclose(void * handle)131 int __dlclose(void* handle) {
132 ScopedPthreadMutexLocker locker(&g_dl_mutex);
133 int result = do_dlclose(handle);
134 if (result != 0) {
135 __bionic_format_dlerror("dlclose failed", linker_get_error_buffer());
136 }
137 return result;
138 }
139
140 // This function is needed by libgcc.a (this is why there is no prefix for this one)
dl_iterate_phdr(int (* cb)(dl_phdr_info * info,size_t size,void * data),void * data)141 int dl_iterate_phdr(int (*cb)(dl_phdr_info* info, size_t size, void* data), void* data) {
142 ScopedPthreadMutexLocker locker(&g_dl_mutex);
143 return do_dl_iterate_phdr(cb, data);
144 }
145
146 #if defined(__arm__)
__dl_unwind_find_exidx(_Unwind_Ptr pc,int * pcount)147 _Unwind_Ptr __dl_unwind_find_exidx(_Unwind_Ptr pc, int* pcount) {
148 ScopedPthreadMutexLocker locker(&g_dl_mutex);
149 return do_dl_unwind_find_exidx(pc, pcount);
150 }
151 #endif
152
__android_set_application_target_sdk_version(uint32_t target)153 void __android_set_application_target_sdk_version(uint32_t target) {
154 // lock to avoid modification in the middle of dlopen.
155 ScopedPthreadMutexLocker locker(&g_dl_mutex);
156 set_application_target_sdk_version(target);
157 }
158
__android_get_application_target_sdk_version()159 uint32_t __android_get_application_target_sdk_version() {
160 return get_application_target_sdk_version();
161 }
162
__android_dlwarning(void * obj,void (* f)(void *,const char *))163 void __android_dlwarning(void* obj, void (*f)(void*, const char*)) {
164 ScopedPthreadMutexLocker locker(&g_dl_mutex);
165 get_dlwarning(obj, f);
166 }
167
__android_init_anonymous_namespace(const char * shared_libs_sonames,const char * library_search_path)168 bool __android_init_anonymous_namespace(const char* shared_libs_sonames,
169 const char* library_search_path) {
170 ScopedPthreadMutexLocker locker(&g_dl_mutex);
171 bool success = init_anonymous_namespace(shared_libs_sonames, library_search_path);
172 if (!success) {
173 __bionic_format_dlerror("android_init_anonymous_namespace failed", linker_get_error_buffer());
174 }
175
176 return success;
177 }
178
__android_create_namespace(const char * name,const char * ld_library_path,const char * default_library_path,uint64_t type,const char * permitted_when_isolated_path,android_namespace_t * parent_namespace,const void * caller_addr)179 android_namespace_t* __android_create_namespace(const char* name,
180 const char* ld_library_path,
181 const char* default_library_path,
182 uint64_t type,
183 const char* permitted_when_isolated_path,
184 android_namespace_t* parent_namespace,
185 const void* caller_addr) {
186 ScopedPthreadMutexLocker locker(&g_dl_mutex);
187
188 android_namespace_t* result = create_namespace(caller_addr,
189 name,
190 ld_library_path,
191 default_library_path,
192 type,
193 permitted_when_isolated_path,
194 parent_namespace);
195
196 if (result == nullptr) {
197 __bionic_format_dlerror("android_create_namespace failed", linker_get_error_buffer());
198 }
199
200 return result;
201 }
202
__android_link_namespaces(android_namespace_t * namespace_from,android_namespace_t * namespace_to,const char * shared_libs_sonames)203 bool __android_link_namespaces(android_namespace_t* namespace_from,
204 android_namespace_t* namespace_to,
205 const char* shared_libs_sonames) {
206 ScopedPthreadMutexLocker locker(&g_dl_mutex);
207
208 bool success = link_namespaces(namespace_from, namespace_to, shared_libs_sonames);
209
210 if (!success) {
211 __bionic_format_dlerror("android_link_namespaces failed", linker_get_error_buffer());
212 }
213
214 return success;
215 }
216
__android_get_exported_namespace(const char * name)217 android_namespace_t* __android_get_exported_namespace(const char* name) {
218 return get_exported_namespace(name);
219 }
220
__cfi_fail(uint64_t CallSiteTypeId,void * Ptr,void * DiagData,void * CallerPc)221 void __cfi_fail(uint64_t CallSiteTypeId, void* Ptr, void *DiagData, void *CallerPc) {
222 CFIShadowWriter::CfiFail(CallSiteTypeId, Ptr, DiagData, CallerPc);
223 }
224
225 // name_offset: starting index of the name in libdl_info.strtab
226 #define ELF32_SYM_INITIALIZER(name_offset, value, shndx) \
227 { name_offset, \
228 reinterpret_cast<Elf32_Addr>(value), \
229 /* st_size */ 0, \
230 ((shndx) == 0) ? 0 : (STB_GLOBAL << 4), \
231 /* st_other */ 0, \
232 shndx, \
233 }
234
235 #define ELF64_SYM_INITIALIZER(name_offset, value, shndx) \
236 { name_offset, \
237 ((shndx) == 0) ? 0 : (STB_GLOBAL << 4), \
238 /* st_other */ 0, \
239 shndx, \
240 reinterpret_cast<Elf64_Addr>(value), \
241 /* st_size */ 0, \
242 }
243
244 static const char ANDROID_LIBDL_STRTAB[] =
245 // 0000000000111111 11112222222222333 333333344444444 44555555555566666 6666677777777778 8888888889999999999
246 // 0123456789012345 67890123456789012 345678901234567 89012345678901234 5678901234567890 1234567890123456789
247 "__loader_dlopen\0__loader_dlclose\0__loader_dlsym\0__loader_dlerror\0__loader_dladdr\0__loader_android_up"
248 // 1*
249 // 000000000011111111112 2222222223333333333444444444455555555 5566666666667777777777888 88888889999999999
250 // 012345678901234567890 1234567890123456789012345678901234567 8901234567890123456789012 34567890123456789
251 "date_LD_LIBRARY_PATH\0__loader_android_get_LD_LIBRARY_PATH\0__loader_dl_iterate_phdr\0__loader_android_"
252 // 2*
253 // 00000000001 1111111112222222222333333333344444444445555555555666 6666666777777777788888888889999999999
254 // 01234567890 1234567890123456789012345678901234567890123456789012 3456789012345678901234567890123456789
255 "dlopen_ext\0__loader_android_set_application_target_sdk_version\0__loader_android_get_application_targ"
256 // 3*
257 // 000000000011111 111112222222222333333333344444444445555555 5556666666666777777777788888888889 999999999
258 // 012345678901234 567890123456789012345678901234567890123456 7890123456789012345678901234567890 123456789
259 "et_sdk_version\0__loader_android_init_anonymous_namespace\0__loader_android_create_namespace\0__loader_"
260 // 4*
261 // 0000000 000111111111122222222223333 333333444444444455 555555556666666666777777777788888 888889999999999
262 // 0123456 789012345678901234567890123 456789012345678901 234567890123456789012345678901234 567890123456789
263 "dlvsym\0__loader_android_dlwarning\0__loader_cfi_fail\0__loader_android_link_namespaces\0__loader_androi"
264 // 5*
265 // 0000000000111111111122222 22222
266 // 0123456789012345678901234 56789
267 "d_get_exported_namespace\0"
268 #if defined(__arm__)
269 // 525
270 "__loader_dl_unwind_find_exidx\0"
271 #endif
272 ;
273
274 static ElfW(Sym) g_libdl_symtab[] = {
275 // Total length of libdl_info.strtab, including trailing 0.
276 // This is actually the STH_UNDEF entry. Technically, it's
277 // supposed to have st_name == 0, but instead, it points to an index
278 // in the strtab with a \0 to make iterating through the symtab easier.
279 ELFW(SYM_INITIALIZER)(sizeof(ANDROID_LIBDL_STRTAB) - 1, nullptr, 0),
280 ELFW(SYM_INITIALIZER)( 0, &__dlopen, 1),
281 ELFW(SYM_INITIALIZER)( 16, &__dlclose, 1),
282 ELFW(SYM_INITIALIZER)( 33, &__dlsym, 1),
283 ELFW(SYM_INITIALIZER)( 48, &__dlerror, 1),
284 ELFW(SYM_INITIALIZER)( 65, &__dladdr, 1),
285 ELFW(SYM_INITIALIZER)( 81, &__android_update_LD_LIBRARY_PATH, 1),
286 ELFW(SYM_INITIALIZER)(121, &__android_get_LD_LIBRARY_PATH, 1),
287 ELFW(SYM_INITIALIZER)(158, &dl_iterate_phdr, 1),
288 ELFW(SYM_INITIALIZER)(183, &__android_dlopen_ext, 1),
289 ELFW(SYM_INITIALIZER)(211, &__android_set_application_target_sdk_version, 1),
290 ELFW(SYM_INITIALIZER)(263, &__android_get_application_target_sdk_version, 1),
291 ELFW(SYM_INITIALIZER)(315, &__android_init_anonymous_namespace, 1),
292 ELFW(SYM_INITIALIZER)(357, &__android_create_namespace, 1),
293 ELFW(SYM_INITIALIZER)(391, &__dlvsym, 1),
294 ELFW(SYM_INITIALIZER)(407, &__android_dlwarning, 1),
295 ELFW(SYM_INITIALIZER)(434, &__cfi_fail, 1),
296 ELFW(SYM_INITIALIZER)(452, &__android_link_namespaces, 1),
297 ELFW(SYM_INITIALIZER)(485, &__android_get_exported_namespace, 1),
298 #if defined(__arm__)
299 ELFW(SYM_INITIALIZER)(525, &__dl_unwind_find_exidx, 1),
300 #endif
301 };
302
303 // Fake out a hash table with a single bucket.
304 //
305 // A search of the hash table will look through g_libdl_symtab starting with index 1, then
306 // use g_libdl_chains to find the next index to look at. g_libdl_chains should be set up to
307 // walk through every element in g_libdl_symtab, and then end with 0 (sentinel value).
308 //
309 // That is, g_libdl_chains should look like { 0, 2, 3, ... N, 0 } where N is the number
310 // of actual symbols, or nelems(g_libdl_symtab)-1 (since the first element of g_libdl_symtab is not
311 // a real symbol). (See soinfo_elf_lookup().)
312 //
313 // Note that adding any new symbols here requires stubbing them out in libdl.
314 static unsigned g_libdl_buckets[1] = { 1 };
315 #if defined(__arm__)
316 static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 0 };
317 #else
318 static unsigned g_libdl_chains[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 0 };
319 #endif
320
321 static uint8_t __libdl_info_buf[sizeof(soinfo)] __attribute__((aligned(8)));
322 static soinfo* __libdl_info = nullptr;
323
324 // This is used by the dynamic linker. Every process gets these symbols for free.
get_libdl_info(const char * linker_path)325 soinfo* get_libdl_info(const char* linker_path) {
326 if (__libdl_info == nullptr) {
327 __libdl_info = new (__libdl_info_buf) soinfo(&g_default_namespace, linker_path, nullptr, 0, 0);
328 __libdl_info->flags_ |= FLAG_LINKED;
329 __libdl_info->strtab_ = ANDROID_LIBDL_STRTAB;
330 __libdl_info->symtab_ = g_libdl_symtab;
331 __libdl_info->nbucket_ = sizeof(g_libdl_buckets)/sizeof(unsigned);
332 __libdl_info->nchain_ = sizeof(g_libdl_chains)/sizeof(unsigned);
333 __libdl_info->bucket_ = g_libdl_buckets;
334 __libdl_info->chain_ = g_libdl_chains;
335 __libdl_info->ref_count_ = 1;
336 __libdl_info->strtab_size_ = sizeof(ANDROID_LIBDL_STRTAB);
337 __libdl_info->local_group_root_ = __libdl_info;
338 __libdl_info->soname_ = "ld-android.so";
339 __libdl_info->target_sdk_version_ = __ANDROID_API__;
340 __libdl_info->generate_handle();
341 #if defined(__work_around_b_24465209__)
342 strlcpy(__libdl_info->old_name_, __libdl_info->soname_, sizeof(__libdl_info->old_name_));
343 #endif
344 }
345
346 return __libdl_info;
347 }
348