1 /*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <unistd.h>
20 #include <string.h>
21 #include <ctype.h>
22 #include <fcntl.h>
23 #include <stdarg.h>
24 #include <dirent.h>
25 #include <limits.h>
26 #include <errno.h>
27
28 #include <cutils/misc.h>
29 #include <cutils/sockets.h>
30
31 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
32 #include <sys/_system_properties.h>
33
34 #include <sys/socket.h>
35 #include <sys/un.h>
36 #include <sys/select.h>
37 #include <sys/types.h>
38 #include <netinet/in.h>
39 #include <sys/mman.h>
40 #include <sys/atomics.h>
41 #include <private/android_filesystem_config.h>
42
43 #include "property_service.h"
44 #include "init.h"
45 #include "util.h"
46 #include "log.h"
47
48 #define PERSISTENT_PROPERTY_DIR "/data/property"
49
50 static int persistent_properties_loaded = 0;
51 static int property_area_inited = 0;
52
53 static int property_set_fd = -1;
54
55 /* White list of permissions for setting property services. */
56 struct {
57 const char *prefix;
58 unsigned int uid;
59 unsigned int gid;
60 } property_perms[] = {
61 { "net.rmnet0.", AID_RADIO, 0 },
62 { "net.gprs.", AID_RADIO, 0 },
63 { "net.ppp", AID_RADIO, 0 },
64 { "net.qmi", AID_RADIO, 0 },
65 { "net.lte", AID_RADIO, 0 },
66 { "net.cdma", AID_RADIO, 0 },
67 { "ril.", AID_RADIO, 0 },
68 { "gsm.", AID_RADIO, 0 },
69 { "persist.radio", AID_RADIO, 0 },
70 { "net.dns", AID_RADIO, 0 },
71 { "sys.usb.config", AID_RADIO, 0 },
72 { "net.", AID_SYSTEM, 0 },
73 { "dev.", AID_SYSTEM, 0 },
74 { "runtime.", AID_SYSTEM, 0 },
75 { "hw.", AID_SYSTEM, 0 },
76 { "sys.", AID_SYSTEM, 0 },
77 { "service.", AID_SYSTEM, 0 },
78 { "wlan.", AID_SYSTEM, 0 },
79 { "dhcp.", AID_SYSTEM, 0 },
80 { "dhcp.", AID_DHCP, 0 },
81 { "debug.", AID_SHELL, 0 },
82 { "log.", AID_SHELL, 0 },
83 { "service.adb.root", AID_SHELL, 0 },
84 { "service.adb.tcp.port", AID_SHELL, 0 },
85 { "persist.sys.", AID_SYSTEM, 0 },
86 { "persist.service.", AID_SYSTEM, 0 },
87 { "persist.security.", AID_SYSTEM, 0 },
88 { NULL, 0, 0 }
89 };
90
91 /*
92 * White list of UID that are allowed to start/stop services.
93 * Currently there are no user apps that require.
94 */
95 struct {
96 const char *service;
97 unsigned int uid;
98 unsigned int gid;
99 } control_perms[] = {
100 { "dumpstate",AID_SHELL, AID_LOG },
101 { "ril-daemon",AID_RADIO, AID_RADIO },
102 {NULL, 0, 0 }
103 };
104
105 typedef struct {
106 void *data;
107 size_t size;
108 int fd;
109 } workspace;
110
init_workspace(workspace * w,size_t size)111 static int init_workspace(workspace *w, size_t size)
112 {
113 void *data;
114 int fd;
115
116 /* dev is a tmpfs that we can use to carve a shared workspace
117 * out of, so let's do that...
118 */
119 fd = open("/dev/__properties__", O_RDWR | O_CREAT, 0600);
120 if (fd < 0)
121 return -1;
122
123 if (ftruncate(fd, size) < 0)
124 goto out;
125
126 data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
127 if(data == MAP_FAILED)
128 goto out;
129
130 close(fd);
131
132 fd = open("/dev/__properties__", O_RDONLY);
133 if (fd < 0)
134 return -1;
135
136 unlink("/dev/__properties__");
137
138 w->data = data;
139 w->size = size;
140 w->fd = fd;
141 return 0;
142
143 out:
144 close(fd);
145 return -1;
146 }
147
148 /* (8 header words + 247 toc words) = 1020 bytes */
149 /* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */
150
151 #define PA_COUNT_MAX 247
152 #define PA_INFO_START 1024
153 #define PA_SIZE 32768
154
155 static workspace pa_workspace;
156 static prop_info *pa_info_array;
157
158 extern prop_area *__system_property_area__;
159
init_property_area(void)160 static int init_property_area(void)
161 {
162 prop_area *pa;
163
164 if(pa_info_array)
165 return -1;
166
167 if(init_workspace(&pa_workspace, PA_SIZE))
168 return -1;
169
170 fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC);
171
172 pa_info_array = (void*) (((char*) pa_workspace.data) + PA_INFO_START);
173
174 pa = pa_workspace.data;
175 memset(pa, 0, PA_SIZE);
176 pa->magic = PROP_AREA_MAGIC;
177 pa->version = PROP_AREA_VERSION;
178
179 /* plug into the lib property services */
180 __system_property_area__ = pa;
181 property_area_inited = 1;
182 return 0;
183 }
184
update_prop_info(prop_info * pi,const char * value,unsigned len)185 static void update_prop_info(prop_info *pi, const char *value, unsigned len)
186 {
187 pi->serial = pi->serial | 1;
188 memcpy(pi->value, value, len + 1);
189 pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff);
190 __futex_wake(&pi->serial, INT32_MAX);
191 }
192
193 /*
194 * Checks permissions for starting/stoping system services.
195 * AID_SYSTEM and AID_ROOT are always allowed.
196 *
197 * Returns 1 if uid allowed, 0 otherwise.
198 */
check_control_perms(const char * name,unsigned int uid,unsigned int gid)199 static int check_control_perms(const char *name, unsigned int uid, unsigned int gid) {
200 int i;
201 if (uid == AID_SYSTEM || uid == AID_ROOT)
202 return 1;
203
204 /* Search the ACL */
205 for (i = 0; control_perms[i].service; i++) {
206 if (strcmp(control_perms[i].service, name) == 0) {
207 if ((uid && control_perms[i].uid == uid) ||
208 (gid && control_perms[i].gid == gid)) {
209 return 1;
210 }
211 }
212 }
213 return 0;
214 }
215
216 /*
217 * Checks permissions for setting system properties.
218 * Returns 1 if uid allowed, 0 otherwise.
219 */
check_perms(const char * name,unsigned int uid,unsigned int gid)220 static int check_perms(const char *name, unsigned int uid, unsigned int gid)
221 {
222 int i;
223 if (uid == 0)
224 return 1;
225
226 if(!strncmp(name, "ro.", 3))
227 name +=3;
228
229 for (i = 0; property_perms[i].prefix; i++) {
230 int tmp;
231 if (strncmp(property_perms[i].prefix, name,
232 strlen(property_perms[i].prefix)) == 0) {
233 if ((uid && property_perms[i].uid == uid) ||
234 (gid && property_perms[i].gid == gid)) {
235 return 1;
236 }
237 }
238 }
239
240 return 0;
241 }
242
property_get(const char * name)243 const char* property_get(const char *name)
244 {
245 prop_info *pi;
246
247 if(strlen(name) >= PROP_NAME_MAX) return 0;
248
249 pi = (prop_info*) __system_property_find(name);
250
251 if(pi != 0) {
252 return pi->value;
253 } else {
254 return 0;
255 }
256 }
257
write_persistent_property(const char * name,const char * value)258 static void write_persistent_property(const char *name, const char *value)
259 {
260 const char *tempPath = PERSISTENT_PROPERTY_DIR "/.temp";
261 char path[PATH_MAX];
262 int fd, length;
263
264 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name);
265
266 fd = open(tempPath, O_WRONLY|O_CREAT|O_TRUNC, 0600);
267 if (fd < 0) {
268 ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno);
269 return;
270 }
271 write(fd, value, strlen(value));
272 close(fd);
273
274 if (rename(tempPath, path)) {
275 unlink(tempPath);
276 ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path);
277 }
278 }
279
property_set(const char * name,const char * value)280 int property_set(const char *name, const char *value)
281 {
282 prop_area *pa;
283 prop_info *pi;
284
285 int namelen = strlen(name);
286 int valuelen = strlen(value);
287
288 if(namelen >= PROP_NAME_MAX) return -1;
289 if(valuelen >= PROP_VALUE_MAX) return -1;
290 if(namelen < 1) return -1;
291
292 pi = (prop_info*) __system_property_find(name);
293
294 if(pi != 0) {
295 /* ro.* properties may NEVER be modified once set */
296 if(!strncmp(name, "ro.", 3)) return -1;
297
298 pa = __system_property_area__;
299 update_prop_info(pi, value, valuelen);
300 pa->serial++;
301 __futex_wake(&pa->serial, INT32_MAX);
302 } else {
303 pa = __system_property_area__;
304 if(pa->count == PA_COUNT_MAX) return -1;
305
306 pi = pa_info_array + pa->count;
307 pi->serial = (valuelen << 24);
308 memcpy(pi->name, name, namelen + 1);
309 memcpy(pi->value, value, valuelen + 1);
310
311 pa->toc[pa->count] =
312 (namelen << 24) | (((unsigned) pi) - ((unsigned) pa));
313
314 pa->count++;
315 pa->serial++;
316 __futex_wake(&pa->serial, INT32_MAX);
317 }
318 /* If name starts with "net." treat as a DNS property. */
319 if (strncmp("net.", name, strlen("net.")) == 0) {
320 if (strcmp("net.change", name) == 0) {
321 return 0;
322 }
323 /*
324 * The 'net.change' property is a special property used track when any
325 * 'net.*' property name is updated. It is _ONLY_ updated here. Its value
326 * contains the last updated 'net.*' property.
327 */
328 property_set("net.change", name);
329 } else if (persistent_properties_loaded &&
330 strncmp("persist.", name, strlen("persist.")) == 0) {
331 /*
332 * Don't write properties to disk until after we have read all default properties
333 * to prevent them from being overwritten by default values.
334 */
335 write_persistent_property(name, value);
336 }
337 property_changed(name, value);
338 return 0;
339 }
340
property_list(void (* propfn)(const char * key,const char * value,void * cookie),void * cookie)341 static int property_list(void (*propfn)(const char *key, const char *value, void *cookie),
342 void *cookie)
343 {
344 char name[PROP_NAME_MAX];
345 char value[PROP_VALUE_MAX];
346 const prop_info *pi;
347 unsigned n;
348
349 for(n = 0; (pi = __system_property_find_nth(n)); n++) {
350 __system_property_read(pi, name, value);
351 propfn(name, value, cookie);
352 }
353 return 0;
354 }
355
handle_property_set_fd()356 void handle_property_set_fd()
357 {
358 prop_msg msg;
359 int s;
360 int r;
361 int res;
362 struct ucred cr;
363 struct sockaddr_un addr;
364 socklen_t addr_size = sizeof(addr);
365 socklen_t cr_size = sizeof(cr);
366
367 if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) {
368 return;
369 }
370
371 /* Check socket options here */
372 if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
373 close(s);
374 ERROR("Unable to recieve socket options\n");
375 return;
376 }
377
378 r = TEMP_FAILURE_RETRY(recv(s, &msg, sizeof(msg), 0));
379 if(r != sizeof(prop_msg)) {
380 ERROR("sys_prop: mis-match msg size recieved: %d expected: %d errno: %d\n",
381 r, sizeof(prop_msg), errno);
382 close(s);
383 return;
384 }
385
386 switch(msg.cmd) {
387 case PROP_MSG_SETPROP:
388 msg.name[PROP_NAME_MAX-1] = 0;
389 msg.value[PROP_VALUE_MAX-1] = 0;
390
391 if(memcmp(msg.name,"ctl.",4) == 0) {
392 // Keep the old close-socket-early behavior when handling
393 // ctl.* properties.
394 close(s);
395 if (check_control_perms(msg.value, cr.uid, cr.gid)) {
396 handle_control_message((char*) msg.name + 4, (char*) msg.value);
397 } else {
398 ERROR("sys_prop: Unable to %s service ctl [%s] uid:%d gid:%d pid:%d\n",
399 msg.name + 4, msg.value, cr.uid, cr.gid, cr.pid);
400 }
401 } else {
402 if (check_perms(msg.name, cr.uid, cr.gid)) {
403 property_set((char*) msg.name, (char*) msg.value);
404 } else {
405 ERROR("sys_prop: permission denied uid:%d name:%s\n",
406 cr.uid, msg.name);
407 }
408
409 // Note: bionic's property client code assumes that the
410 // property server will not close the socket until *AFTER*
411 // the property is written to memory.
412 close(s);
413 }
414 break;
415
416 default:
417 close(s);
418 break;
419 }
420 }
421
get_property_workspace(int * fd,int * sz)422 void get_property_workspace(int *fd, int *sz)
423 {
424 *fd = pa_workspace.fd;
425 *sz = pa_workspace.size;
426 }
427
load_properties(char * data)428 static void load_properties(char *data)
429 {
430 char *key, *value, *eol, *sol, *tmp;
431
432 sol = data;
433 while((eol = strchr(sol, '\n'))) {
434 key = sol;
435 *eol++ = 0;
436 sol = eol;
437
438 value = strchr(key, '=');
439 if(value == 0) continue;
440 *value++ = 0;
441
442 while(isspace(*key)) key++;
443 if(*key == '#') continue;
444 tmp = value - 2;
445 while((tmp > key) && isspace(*tmp)) *tmp-- = 0;
446
447 while(isspace(*value)) value++;
448 tmp = eol - 2;
449 while((tmp > value) && isspace(*tmp)) *tmp-- = 0;
450
451 property_set(key, value);
452 }
453 }
454
load_properties_from_file(const char * fn)455 static void load_properties_from_file(const char *fn)
456 {
457 char *data;
458 unsigned sz;
459
460 data = read_file(fn, &sz);
461
462 if(data != 0) {
463 load_properties(data);
464 free(data);
465 }
466 }
467
load_persistent_properties()468 static void load_persistent_properties()
469 {
470 DIR* dir = opendir(PERSISTENT_PROPERTY_DIR);
471 struct dirent* entry;
472 char path[PATH_MAX];
473 char value[PROP_VALUE_MAX];
474 int fd, length;
475
476 if (dir) {
477 while ((entry = readdir(dir)) != NULL) {
478 if (strncmp("persist.", entry->d_name, strlen("persist.")))
479 continue;
480 #if HAVE_DIRENT_D_TYPE
481 if (entry->d_type != DT_REG)
482 continue;
483 #endif
484 /* open the file and read the property value */
485 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, entry->d_name);
486 fd = open(path, O_RDONLY);
487 if (fd >= 0) {
488 length = read(fd, value, sizeof(value) - 1);
489 if (length >= 0) {
490 value[length] = 0;
491 property_set(entry->d_name, value);
492 } else {
493 ERROR("Unable to read persistent property file %s errno: %d\n", path, errno);
494 }
495 close(fd);
496 } else {
497 ERROR("Unable to open persistent property file %s errno: %d\n", path, errno);
498 }
499 }
500 closedir(dir);
501 } else {
502 ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno);
503 }
504
505 persistent_properties_loaded = 1;
506 }
507
property_init(bool load_defaults)508 void property_init(bool load_defaults)
509 {
510 init_property_area();
511 if (load_defaults)
512 load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT);
513 }
514
properties_inited(void)515 int properties_inited(void)
516 {
517 return property_area_inited;
518 }
519
520 /* When booting an encrypted system, /data is not mounted when the
521 * property service is started, so any properties stored there are
522 * not loaded. Vold triggers init to load these properties once it
523 * has mounted /data.
524 */
load_persist_props(void)525 void load_persist_props(void)
526 {
527 load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE);
528 /* Read persistent properties after all default values have been loaded. */
529 load_persistent_properties();
530 }
531
start_property_service(void)532 void start_property_service(void)
533 {
534 int fd;
535
536 load_properties_from_file(PROP_PATH_SYSTEM_BUILD);
537 load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT);
538 load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE);
539 /* Read persistent properties after all default values have been loaded. */
540 load_persistent_properties();
541
542 fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0);
543 if(fd < 0) return;
544 fcntl(fd, F_SETFD, FD_CLOEXEC);
545 fcntl(fd, F_SETFL, O_NONBLOCK);
546
547 listen(fd, 8);
548 property_set_fd = fd;
549 }
550
get_property_set_fd()551 int get_property_set_fd()
552 {
553 return property_set_fd;
554 }
555