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