| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <ctype.h> |
| #include <fcntl.h> |
| #include <stdarg.h> |
| #include <dirent.h> |
| #include <limits.h> |
| #include <errno.h> |
| |
| #include <cutils/misc.h> |
| #include <cutils/sockets.h> |
| #include <cutils/multiuser.h> |
| |
| #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ |
| #include <sys/_system_properties.h> |
| |
| #include <sys/socket.h> |
| #include <sys/un.h> |
| #include <sys/select.h> |
| #include <sys/types.h> |
| #include <netinet/in.h> |
| #include <sys/mman.h> |
| #include <sys/atomics.h> |
| #include <private/android_filesystem_config.h> |
| |
| #include <selinux/selinux.h> |
| #include <selinux/label.h> |
| |
| #include "property_service.h" |
| #include "init.h" |
| #include "util.h" |
| #include "log.h" |
| |
| #define PERSISTENT_PROPERTY_DIR "/data/property" |
| |
| static int persistent_properties_loaded = 0; |
| static int property_area_inited = 0; |
| |
| static int property_set_fd = -1; |
| |
| /* White list of permissions for setting property services. */ |
| struct { |
| const char *prefix; |
| unsigned int uid; |
| unsigned int gid; |
| } property_perms[] = { |
| { "net.rmnet0.", AID_RADIO, 0 }, |
| { "net.gprs.", AID_RADIO, 0 }, |
| { "net.ppp", AID_RADIO, 0 }, |
| { "net.qmi", AID_RADIO, 0 }, |
| { "net.lte", AID_RADIO, 0 }, |
| { "net.cdma", AID_RADIO, 0 }, |
| { "ril.", AID_RADIO, 0 }, |
| { "gsm.", AID_RADIO, 0 }, |
| { "persist.radio", AID_RADIO, 0 }, |
| { "net.dns", AID_RADIO, 0 }, |
| { "sys.usb.config", AID_RADIO, 0 }, |
| { "net.", AID_SYSTEM, 0 }, |
| { "dev.", AID_SYSTEM, 0 }, |
| { "runtime.", AID_SYSTEM, 0 }, |
| { "hw.", AID_SYSTEM, 0 }, |
| { "sys.", AID_SYSTEM, 0 }, |
| { "service.", AID_SYSTEM, 0 }, |
| { "wlan.", AID_SYSTEM, 0 }, |
| { "bluetooth.", AID_BLUETOOTH, 0 }, |
| { "dhcp.", AID_SYSTEM, 0 }, |
| { "dhcp.", AID_DHCP, 0 }, |
| { "debug.", AID_SYSTEM, 0 }, |
| { "debug.", AID_SHELL, 0 }, |
| { "log.", AID_SHELL, 0 }, |
| { "service.adb.root", AID_SHELL, 0 }, |
| { "service.adb.tcp.port", AID_SHELL, 0 }, |
| { "persist.sys.", AID_SYSTEM, 0 }, |
| { "persist.service.", AID_SYSTEM, 0 }, |
| { "persist.security.", AID_SYSTEM, 0 }, |
| { "persist.service.bdroid.", AID_BLUETOOTH, 0 }, |
| { "selinux." , AID_SYSTEM, 0 }, |
| { NULL, 0, 0 } |
| }; |
| |
| /* |
| * White list of UID that are allowed to start/stop services. |
| * Currently there are no user apps that require. |
| */ |
| struct { |
| const char *service; |
| unsigned int uid; |
| unsigned int gid; |
| } control_perms[] = { |
| { "dumpstate",AID_SHELL, AID_LOG }, |
| { "ril-daemon",AID_RADIO, AID_RADIO }, |
| {NULL, 0, 0 } |
| }; |
| |
| typedef struct { |
| void *data; |
| size_t size; |
| int fd; |
| } workspace; |
| |
| static int init_workspace(workspace *w, size_t size) |
| { |
| void *data; |
| int fd; |
| |
| /* dev is a tmpfs that we can use to carve a shared workspace |
| * out of, so let's do that... |
| */ |
| fd = open(PROP_FILENAME, O_RDWR | O_CREAT | O_NOFOLLOW, 0644); |
| if (fd < 0) |
| return -1; |
| |
| if (ftruncate(fd, size) < 0) |
| goto out; |
| |
| data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); |
| if(data == MAP_FAILED) |
| goto out; |
| |
| close(fd); |
| |
| fd = open(PROP_FILENAME, O_RDONLY | O_NOFOLLOW); |
| if (fd < 0) |
| return -1; |
| |
| w->data = data; |
| w->size = size; |
| w->fd = fd; |
| return 0; |
| |
| out: |
| close(fd); |
| return -1; |
| } |
| |
| /* (8 header words + 372 toc words) = 1520 bytes */ |
| /* 1536 bytes header and toc + 372 prop_infos @ 128 bytes = 49152 bytes */ |
| |
| #define PA_COUNT_MAX 372 |
| #define PA_INFO_START 1536 |
| #define PA_SIZE 49152 |
| |
| static workspace pa_workspace; |
| static prop_info *pa_info_array; |
| |
| extern prop_area *__system_property_area__; |
| |
| static int init_property_area(void) |
| { |
| prop_area *pa; |
| |
| if(pa_info_array) |
| return -1; |
| |
| if(init_workspace(&pa_workspace, PA_SIZE)) |
| return -1; |
| |
| fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC); |
| |
| pa_info_array = (void*) (((char*) pa_workspace.data) + PA_INFO_START); |
| |
| pa = pa_workspace.data; |
| memset(pa, 0, PA_SIZE); |
| pa->magic = PROP_AREA_MAGIC; |
| pa->version = PROP_AREA_VERSION; |
| |
| /* plug into the lib property services */ |
| __system_property_area__ = pa; |
| property_area_inited = 1; |
| return 0; |
| } |
| |
| static void update_prop_info(prop_info *pi, const char *value, unsigned len) |
| { |
| pi->serial = pi->serial | 1; |
| memcpy(pi->value, value, len + 1); |
| pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff); |
| __futex_wake(&pi->serial, INT32_MAX); |
| } |
| |
| static int check_mac_perms(const char *name, char *sctx) |
| { |
| if (is_selinux_enabled() <= 0) |
| return 1; |
| |
| char *tctx = NULL; |
| const char *class = "property_service"; |
| const char *perm = "set"; |
| int result = 0; |
| |
| if (!sctx) |
| goto err; |
| |
| if (!sehandle_prop) |
| goto err; |
| |
| if (selabel_lookup(sehandle_prop, &tctx, name, 1) != 0) |
| goto err; |
| |
| if (selinux_check_access(sctx, tctx, class, perm, name) == 0) |
| result = 1; |
| |
| freecon(tctx); |
| err: |
| return result; |
| } |
| |
| static int check_control_mac_perms(const char *name, char *sctx) |
| { |
| /* |
| * Create a name prefix out of ctl.<service name> |
| * The new prefix allows the use of the existing |
| * property service backend labeling while avoiding |
| * mislabels based on true property prefixes. |
| */ |
| char ctl_name[PROP_VALUE_MAX+4]; |
| int ret = snprintf(ctl_name, sizeof(ctl_name), "ctl.%s", name); |
| |
| if (ret < 0 || (size_t) ret >= sizeof(ctl_name)) |
| return 0; |
| |
| return check_mac_perms(ctl_name, sctx); |
| } |
| |
| /* |
| * Checks permissions for starting/stoping system services. |
| * AID_SYSTEM and AID_ROOT are always allowed. |
| * |
| * Returns 1 if uid allowed, 0 otherwise. |
| */ |
| static int check_control_perms(const char *name, unsigned int uid, unsigned int gid, char *sctx) { |
| |
| int i; |
| if (uid == AID_SYSTEM || uid == AID_ROOT) |
| return check_control_mac_perms(name, sctx); |
| |
| /* Search the ACL */ |
| for (i = 0; control_perms[i].service; i++) { |
| if (strcmp(control_perms[i].service, name) == 0) { |
| if ((uid && control_perms[i].uid == uid) || |
| (gid && control_perms[i].gid == gid)) { |
| return check_control_mac_perms(name, sctx); |
| } |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Checks permissions for setting system properties. |
| * Returns 1 if uid allowed, 0 otherwise. |
| */ |
| static int check_perms(const char *name, unsigned int uid, unsigned int gid, char *sctx) |
| { |
| int i; |
| unsigned int app_id; |
| |
| if(!strncmp(name, "ro.", 3)) |
| name +=3; |
| |
| if (uid == 0) |
| return check_mac_perms(name, sctx); |
| |
| app_id = multiuser_get_app_id(uid); |
| if (app_id == AID_BLUETOOTH) { |
| uid = app_id; |
| } |
| |
| for (i = 0; property_perms[i].prefix; i++) { |
| if (strncmp(property_perms[i].prefix, name, |
| strlen(property_perms[i].prefix)) == 0) { |
| if ((uid && property_perms[i].uid == uid) || |
| (gid && property_perms[i].gid == gid)) { |
| |
| return check_mac_perms(name, sctx); |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| const char* property_get(const char *name) |
| { |
| prop_info *pi; |
| |
| if(strlen(name) >= PROP_NAME_MAX) return 0; |
| |
| pi = (prop_info*) __system_property_find(name); |
| |
| if(pi != 0) { |
| return pi->value; |
| } else { |
| return 0; |
| } |
| } |
| |
| static void write_persistent_property(const char *name, const char *value) |
| { |
| char tempPath[PATH_MAX]; |
| char path[PATH_MAX]; |
| int fd; |
| |
| snprintf(tempPath, sizeof(tempPath), "%s/.temp.XXXXXX", PERSISTENT_PROPERTY_DIR); |
| fd = mkstemp(tempPath); |
| if (fd < 0) { |
| ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno); |
| return; |
| } |
| write(fd, value, strlen(value)); |
| close(fd); |
| |
| snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name); |
| if (rename(tempPath, path)) { |
| unlink(tempPath); |
| ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path); |
| } |
| } |
| |
| int property_set(const char *name, const char *value) |
| { |
| prop_area *pa; |
| prop_info *pi; |
| |
| size_t namelen = strlen(name); |
| size_t valuelen = strlen(value); |
| |
| if(namelen >= PROP_NAME_MAX) return -1; |
| if(valuelen >= PROP_VALUE_MAX) return -1; |
| if(namelen < 1) return -1; |
| |
| pi = (prop_info*) __system_property_find(name); |
| |
| if(pi != 0) { |
| /* ro.* properties may NEVER be modified once set */ |
| if(!strncmp(name, "ro.", 3)) return -1; |
| |
| pa = __system_property_area__; |
| update_prop_info(pi, value, valuelen); |
| pa->serial++; |
| __futex_wake(&pa->serial, INT32_MAX); |
| } else { |
| pa = __system_property_area__; |
| if(pa->count == PA_COUNT_MAX) return -1; |
| |
| pi = pa_info_array + pa->count; |
| pi->serial = (valuelen << 24); |
| memcpy(pi->name, name, namelen + 1); |
| memcpy(pi->value, value, valuelen + 1); |
| |
| pa->toc[pa->count] = |
| (namelen << 24) | (((unsigned) pi) - ((unsigned) pa)); |
| |
| pa->count++; |
| pa->serial++; |
| __futex_wake(&pa->serial, INT32_MAX); |
| } |
| /* If name starts with "net." treat as a DNS property. */ |
| if (strncmp("net.", name, strlen("net.")) == 0) { |
| if (strcmp("net.change", name) == 0) { |
| return 0; |
| } |
| /* |
| * The 'net.change' property is a special property used track when any |
| * 'net.*' property name is updated. It is _ONLY_ updated here. Its value |
| * contains the last updated 'net.*' property. |
| */ |
| property_set("net.change", name); |
| } else if (persistent_properties_loaded && |
| strncmp("persist.", name, strlen("persist.")) == 0) { |
| /* |
| * Don't write properties to disk until after we have read all default properties |
| * to prevent them from being overwritten by default values. |
| */ |
| write_persistent_property(name, value); |
| } else if (strcmp("selinux.reload_policy", name) == 0 && |
| strcmp("1", value) == 0) { |
| selinux_reload_policy(); |
| } |
| property_changed(name, value); |
| return 0; |
| } |
| |
| void handle_property_set_fd() |
| { |
| prop_msg msg; |
| int s; |
| int r; |
| int res; |
| struct ucred cr; |
| struct sockaddr_un addr; |
| socklen_t addr_size = sizeof(addr); |
| socklen_t cr_size = sizeof(cr); |
| char * source_ctx = NULL; |
| |
| if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) { |
| return; |
| } |
| |
| /* Check socket options here */ |
| if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) { |
| close(s); |
| ERROR("Unable to receive socket options\n"); |
| return; |
| } |
| |
| r = TEMP_FAILURE_RETRY(recv(s, &msg, sizeof(msg), 0)); |
| if(r != sizeof(prop_msg)) { |
| ERROR("sys_prop: mis-match msg size received: %d expected: %d errno: %d\n", |
| r, sizeof(prop_msg), errno); |
| close(s); |
| return; |
| } |
| |
| switch(msg.cmd) { |
| case PROP_MSG_SETPROP: |
| msg.name[PROP_NAME_MAX-1] = 0; |
| msg.value[PROP_VALUE_MAX-1] = 0; |
| |
| getpeercon(s, &source_ctx); |
| |
| if(memcmp(msg.name,"ctl.",4) == 0) { |
| // Keep the old close-socket-early behavior when handling |
| // ctl.* properties. |
| close(s); |
| if (check_control_perms(msg.value, cr.uid, cr.gid, source_ctx)) { |
| handle_control_message((char*) msg.name + 4, (char*) msg.value); |
| } else { |
| ERROR("sys_prop: Unable to %s service ctl [%s] uid:%d gid:%d pid:%d\n", |
| msg.name + 4, msg.value, cr.uid, cr.gid, cr.pid); |
| } |
| } else { |
| if (check_perms(msg.name, cr.uid, cr.gid, source_ctx)) { |
| property_set((char*) msg.name, (char*) msg.value); |
| } else { |
| ERROR("sys_prop: permission denied uid:%d name:%s\n", |
| cr.uid, msg.name); |
| } |
| |
| // Note: bionic's property client code assumes that the |
| // property server will not close the socket until *AFTER* |
| // the property is written to memory. |
| close(s); |
| } |
| freecon(source_ctx); |
| break; |
| |
| default: |
| close(s); |
| break; |
| } |
| } |
| |
| void get_property_workspace(int *fd, int *sz) |
| { |
| *fd = pa_workspace.fd; |
| *sz = pa_workspace.size; |
| } |
| |
| static void load_properties(char *data) |
| { |
| char *key, *value, *eol, *sol, *tmp; |
| |
| sol = data; |
| while((eol = strchr(sol, '\n'))) { |
| key = sol; |
| *eol++ = 0; |
| sol = eol; |
| |
| value = strchr(key, '='); |
| if(value == 0) continue; |
| *value++ = 0; |
| |
| while(isspace(*key)) key++; |
| if(*key == '#') continue; |
| tmp = value - 2; |
| while((tmp > key) && isspace(*tmp)) *tmp-- = 0; |
| |
| while(isspace(*value)) value++; |
| tmp = eol - 2; |
| while((tmp > value) && isspace(*tmp)) *tmp-- = 0; |
| |
| property_set(key, value); |
| } |
| } |
| |
| static void load_properties_from_file(const char *fn) |
| { |
| char *data; |
| unsigned sz; |
| |
| data = read_file(fn, &sz); |
| |
| if(data != 0) { |
| load_properties(data); |
| free(data); |
| } |
| } |
| |
| static void load_persistent_properties() |
| { |
| DIR* dir = opendir(PERSISTENT_PROPERTY_DIR); |
| int dir_fd; |
| struct dirent* entry; |
| char value[PROP_VALUE_MAX]; |
| int fd, length; |
| struct stat sb; |
| |
| if (dir) { |
| dir_fd = dirfd(dir); |
| while ((entry = readdir(dir)) != NULL) { |
| if (strncmp("persist.", entry->d_name, strlen("persist."))) |
| continue; |
| #if HAVE_DIRENT_D_TYPE |
| if (entry->d_type != DT_REG) |
| continue; |
| #endif |
| /* open the file and read the property value */ |
| fd = openat(dir_fd, entry->d_name, O_RDONLY | O_NOFOLLOW); |
| if (fd < 0) { |
| ERROR("Unable to open persistent property file \"%s\" errno: %d\n", |
| entry->d_name, errno); |
| continue; |
| } |
| if (fstat(fd, &sb) < 0) { |
| ERROR("fstat on property file \"%s\" failed errno: %d\n", entry->d_name, errno); |
| close(fd); |
| continue; |
| } |
| |
| // File must not be accessible to others, be owned by root/root, and |
| // not be a hard link to any other file. |
| if (((sb.st_mode & (S_IRWXG | S_IRWXO)) != 0) |
| || (sb.st_uid != 0) |
| || (sb.st_gid != 0) |
| || (sb.st_nlink != 1)) { |
| ERROR("skipping insecure property file %s (uid=%lu gid=%lu nlink=%d mode=%o)\n", |
| entry->d_name, sb.st_uid, sb.st_gid, sb.st_nlink, sb.st_mode); |
| close(fd); |
| continue; |
| } |
| |
| length = read(fd, value, sizeof(value) - 1); |
| if (length >= 0) { |
| value[length] = 0; |
| property_set(entry->d_name, value); |
| } else { |
| ERROR("Unable to read persistent property file %s errno: %d\n", |
| entry->d_name, errno); |
| } |
| close(fd); |
| } |
| closedir(dir); |
| } else { |
| ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno); |
| } |
| |
| persistent_properties_loaded = 1; |
| } |
| |
| void property_init(void) |
| { |
| init_property_area(); |
| } |
| |
| void property_load_boot_defaults(void) |
| { |
| load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT); |
| } |
| |
| int properties_inited(void) |
| { |
| return property_area_inited; |
| } |
| |
| static void load_override_properties() { |
| #ifdef ALLOW_LOCAL_PROP_OVERRIDE |
| const char *debuggable = property_get("ro.debuggable"); |
| if (debuggable && (strcmp(debuggable, "1") == 0)) { |
| load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE); |
| } |
| #endif /* ALLOW_LOCAL_PROP_OVERRIDE */ |
| } |
| |
| |
| /* When booting an encrypted system, /data is not mounted when the |
| * property service is started, so any properties stored there are |
| * not loaded. Vold triggers init to load these properties once it |
| * has mounted /data. |
| */ |
| void load_persist_props(void) |
| { |
| load_override_properties(); |
| /* Read persistent properties after all default values have been loaded. */ |
| load_persistent_properties(); |
| } |
| |
| void start_property_service(void) |
| { |
| int fd; |
| |
| load_properties_from_file(PROP_PATH_SYSTEM_BUILD); |
| load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT); |
| load_override_properties(); |
| /* Read persistent properties after all default values have been loaded. */ |
| load_persistent_properties(); |
| |
| fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0); |
| if(fd < 0) return; |
| fcntl(fd, F_SETFD, FD_CLOEXEC); |
| fcntl(fd, F_SETFL, O_NONBLOCK); |
| |
| listen(fd, 8); |
| property_set_fd = fd; |
| } |
| |
| int get_property_set_fd() |
| { |
| return property_set_fd; |
| } |
