| /* |
| * 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 "property_service.h" |
| |
| #include <ctype.h> |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <inttypes.h> |
| #include <limits.h> |
| #include <netinet/in.h> |
| #include <stdarg.h> |
| #include <stddef.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/poll.h> |
| #include <sys/select.h> |
| #include <sys/types.h> |
| #include <sys/un.h> |
| #include <unistd.h> |
| |
| #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ |
| #include <sys/_system_properties.h> |
| |
| #include <memory> |
| #include <vector> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| #include <bootimg.h> |
| #include <fs_mgr.h> |
| #include <selinux/android.h> |
| #include <selinux/label.h> |
| #include <selinux/selinux.h> |
| |
| #include "init.h" |
| #include "util.h" |
| |
| using android::base::StringPrintf; |
| |
| #define PERSISTENT_PROPERTY_DIR "/data/property" |
| #define RECOVERY_MOUNT_POINT "/recovery" |
| |
| static int persistent_properties_loaded = 0; |
| |
| static int property_set_fd = -1; |
| |
| void property_init() { |
| if (__system_property_area_init()) { |
| LOG(ERROR) << "Failed to initialize property area"; |
| exit(1); |
| } |
| } |
| |
| static bool check_mac_perms(const std::string& name, char* sctx, struct ucred* cr) { |
| |
| if (!sctx) { |
| return false; |
| } |
| |
| if (!sehandle_prop) { |
| return false; |
| } |
| |
| char* tctx = nullptr; |
| if (selabel_lookup(sehandle_prop, &tctx, name.c_str(), 1) != 0) { |
| return false; |
| } |
| |
| property_audit_data audit_data; |
| |
| audit_data.name = name.c_str(); |
| audit_data.cr = cr; |
| |
| bool has_access = (selinux_check_access(sctx, tctx, "property_service", "set", &audit_data) == 0); |
| |
| freecon(tctx); |
| return has_access; |
| } |
| |
| static int check_control_mac_perms(const char *name, char *sctx, struct ucred *cr) |
| { |
| /* |
| * 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, cr); |
| } |
| |
| 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) { |
| PLOG(ERROR) << "Unable to write persistent property to temp file " << tempPath; |
| return; |
| } |
| write(fd, value, strlen(value)); |
| fsync(fd); |
| close(fd); |
| |
| snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name); |
| if (rename(tempPath, path)) { |
| PLOG(ERROR) << "Unable to rename persistent property file " << tempPath << " to " << path; |
| unlink(tempPath); |
| } |
| } |
| |
| bool is_legal_property_name(const std::string& name) { |
| size_t namelen = name.size(); |
| |
| if (namelen < 1) return false; |
| if (name[0] == '.') return false; |
| if (name[namelen - 1] == '.') return false; |
| |
| /* Only allow alphanumeric, plus '.', '-', '@', or '_' */ |
| /* Don't allow ".." to appear in a property name */ |
| for (size_t i = 0; i < namelen; i++) { |
| if (name[i] == '.') { |
| // i=0 is guaranteed to never have a dot. See above. |
| if (name[i-1] == '.') return false; |
| continue; |
| } |
| if (name[i] == '_' || name[i] == '-' || name[i] == '@') continue; |
| if (name[i] >= 'a' && name[i] <= 'z') continue; |
| if (name[i] >= 'A' && name[i] <= 'Z') continue; |
| if (name[i] >= '0' && name[i] <= '9') continue; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| uint32_t property_set(const std::string& name, const std::string& value) { |
| size_t valuelen = value.size(); |
| |
| if (!is_legal_property_name(name)) { |
| LOG(ERROR) << "property_set(\"" << name << "\", \"" << value << "\") failed: bad name"; |
| return PROP_ERROR_INVALID_NAME; |
| } |
| |
| if (valuelen >= PROP_VALUE_MAX) { |
| LOG(ERROR) << "property_set(\"" << name << "\", \"" << value << "\") failed: " |
| << "value too long"; |
| return PROP_ERROR_INVALID_VALUE; |
| } |
| |
| if (name == "selinux.restorecon_recursive" && valuelen > 0) { |
| if (restorecon(value.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) { |
| LOG(ERROR) << "Failed to restorecon_recursive " << value; |
| } |
| } |
| |
| prop_info* pi = (prop_info*) __system_property_find(name.c_str()); |
| if (pi != nullptr) { |
| // ro.* properties are actually "write-once". |
| if (android::base::StartsWith(name, "ro.")) { |
| LOG(ERROR) << "property_set(\"" << name << "\", \"" << value << "\") failed: " |
| << "property already set"; |
| return PROP_ERROR_READ_ONLY_PROPERTY; |
| } |
| |
| __system_property_update(pi, value.c_str(), valuelen); |
| } else { |
| int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen); |
| if (rc < 0) { |
| LOG(ERROR) << "property_set(\"" << name << "\", \"" << value << "\") failed: " |
| << "__system_property_add failed"; |
| return PROP_ERROR_SET_FAILED; |
| } |
| } |
| |
| // Don't write properties to disk until after we have read all default |
| // properties to prevent them from being overwritten by default values. |
| if (persistent_properties_loaded && android::base::StartsWith(name, "persist.")) { |
| write_persistent_property(name.c_str(), value.c_str()); |
| } |
| property_changed(name.c_str(), value.c_str()); |
| return PROP_SUCCESS; |
| } |
| |
| class SocketConnection { |
| public: |
| SocketConnection(int socket, const struct ucred& cred) |
| : socket_(socket), cred_(cred) {} |
| |
| ~SocketConnection() { |
| close(socket_); |
| } |
| |
| bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) { |
| return RecvFully(value, sizeof(*value), timeout_ms); |
| } |
| |
| bool RecvChars(char* chars, size_t size, uint32_t* timeout_ms) { |
| return RecvFully(chars, size, timeout_ms); |
| } |
| |
| bool RecvString(std::string* value, uint32_t* timeout_ms) { |
| uint32_t len = 0; |
| if (!RecvUint32(&len, timeout_ms)) { |
| return false; |
| } |
| |
| if (len == 0) { |
| *value = ""; |
| return true; |
| } |
| |
| // http://b/35166374: don't allow init to make arbitrarily large allocations. |
| if (len > 0xffff) { |
| LOG(ERROR) << "sys_prop: RecvString asked to read huge string: " << len; |
| errno = ENOMEM; |
| return false; |
| } |
| |
| std::vector<char> chars(len); |
| if (!RecvChars(&chars[0], len, timeout_ms)) { |
| return false; |
| } |
| |
| *value = std::string(&chars[0], len); |
| return true; |
| } |
| |
| bool SendUint32(uint32_t value) { |
| int result = TEMP_FAILURE_RETRY(send(socket_, &value, sizeof(value), 0)); |
| return result == sizeof(value); |
| } |
| |
| int socket() { |
| return socket_; |
| } |
| |
| const struct ucred& cred() { |
| return cred_; |
| } |
| |
| private: |
| bool PollIn(uint32_t* timeout_ms) { |
| struct pollfd ufds[1]; |
| ufds[0].fd = socket_; |
| ufds[0].events = POLLIN; |
| ufds[0].revents = 0; |
| while (*timeout_ms > 0) { |
| Timer timer; |
| int nr = poll(ufds, 1, *timeout_ms); |
| uint64_t millis = timer.duration_ms(); |
| *timeout_ms = (millis > *timeout_ms) ? 0 : *timeout_ms - millis; |
| |
| if (nr > 0) { |
| return true; |
| } |
| |
| if (nr == 0) { |
| // Timeout |
| break; |
| } |
| |
| if (nr < 0 && errno != EINTR) { |
| PLOG(ERROR) << "sys_prop: error waiting for uid " << cred_.uid << " to send property message"; |
| return false; |
| } else { // errno == EINTR |
| // Timer rounds milliseconds down in case of EINTR we want it to be rounded up |
| // to avoid slowing init down by causing EINTR with under millisecond timeout. |
| if (*timeout_ms > 0) { |
| --(*timeout_ms); |
| } |
| } |
| } |
| |
| LOG(ERROR) << "sys_prop: timeout waiting for uid " << cred_.uid << " to send property message."; |
| return false; |
| } |
| |
| bool RecvFully(void* data_ptr, size_t size, uint32_t* timeout_ms) { |
| size_t bytes_left = size; |
| char* data = static_cast<char*>(data_ptr); |
| while (*timeout_ms > 0 && bytes_left > 0) { |
| if (!PollIn(timeout_ms)) { |
| return false; |
| } |
| |
| int result = TEMP_FAILURE_RETRY(recv(socket_, data, bytes_left, MSG_DONTWAIT)); |
| if (result <= 0) { |
| return false; |
| } |
| |
| bytes_left -= result; |
| data += result; |
| } |
| |
| return bytes_left == 0; |
| } |
| |
| int socket_; |
| struct ucred cred_; |
| |
| DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection); |
| }; |
| |
| static void handle_property_set(SocketConnection& socket, |
| const std::string& name, |
| const std::string& value, |
| bool legacy_protocol) { |
| const char* cmd_name = legacy_protocol ? "PROP_MSG_SETPROP" : "PROP_MSG_SETPROP2"; |
| if (!is_legal_property_name(name)) { |
| LOG(ERROR) << "sys_prop(" << cmd_name << "): illegal property name \"" << name << "\""; |
| socket.SendUint32(PROP_ERROR_INVALID_NAME); |
| return; |
| } |
| |
| struct ucred cr = socket.cred(); |
| char* source_ctx = nullptr; |
| getpeercon(socket.socket(), &source_ctx); |
| |
| if (android::base::StartsWith(name, "ctl.")) { |
| if (check_control_mac_perms(value.c_str(), source_ctx, &cr)) { |
| handle_control_message(name.c_str() + 4, value.c_str()); |
| if (!legacy_protocol) { |
| socket.SendUint32(PROP_SUCCESS); |
| } |
| } else { |
| LOG(ERROR) << "sys_prop(" << cmd_name << "): Unable to " << (name.c_str() + 4) |
| << " service ctl [" << value << "]" |
| << " uid:" << cr.uid |
| << " gid:" << cr.gid |
| << " pid:" << cr.pid; |
| if (!legacy_protocol) { |
| socket.SendUint32(PROP_ERROR_HANDLE_CONTROL_MESSAGE); |
| } |
| } |
| } else { |
| if (check_mac_perms(name, source_ctx, &cr)) { |
| uint32_t result = property_set(name, value); |
| if (!legacy_protocol) { |
| socket.SendUint32(result); |
| } |
| } else { |
| LOG(ERROR) << "sys_prop(" << cmd_name << "): permission denied uid:" << cr.uid << " name:" << name; |
| if (!legacy_protocol) { |
| socket.SendUint32(PROP_ERROR_PERMISSION_DENIED); |
| } |
| } |
| } |
| |
| freecon(source_ctx); |
| } |
| |
| static void handle_property_set_fd() { |
| static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */ |
| |
| int s = accept4(property_set_fd, nullptr, nullptr, SOCK_CLOEXEC); |
| if (s == -1) { |
| return; |
| } |
| |
| struct ucred cr; |
| socklen_t cr_size = sizeof(cr); |
| if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) { |
| close(s); |
| PLOG(ERROR) << "sys_prop: unable to get SO_PEERCRED"; |
| return; |
| } |
| |
| SocketConnection socket(s, cr); |
| uint32_t timeout_ms = kDefaultSocketTimeout; |
| |
| uint32_t cmd = 0; |
| if (!socket.RecvUint32(&cmd, &timeout_ms)) { |
| PLOG(ERROR) << "sys_prop: error while reading command from the socket"; |
| socket.SendUint32(PROP_ERROR_READ_CMD); |
| return; |
| } |
| |
| switch (cmd) { |
| case PROP_MSG_SETPROP: { |
| char prop_name[PROP_NAME_MAX]; |
| char prop_value[PROP_VALUE_MAX]; |
| |
| if (!socket.RecvChars(prop_name, PROP_NAME_MAX, &timeout_ms) || |
| !socket.RecvChars(prop_value, PROP_VALUE_MAX, &timeout_ms)) { |
| PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP): error while reading name/value from the socket"; |
| return; |
| } |
| |
| prop_name[PROP_NAME_MAX-1] = 0; |
| prop_value[PROP_VALUE_MAX-1] = 0; |
| |
| handle_property_set(socket, prop_value, prop_value, true); |
| break; |
| } |
| |
| case PROP_MSG_SETPROP2: { |
| std::string name; |
| std::string value; |
| if (!socket.RecvString(&name, &timeout_ms) || |
| !socket.RecvString(&value, &timeout_ms)) { |
| PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP2): error while reading name/value from the socket"; |
| socket.SendUint32(PROP_ERROR_READ_DATA); |
| return; |
| } |
| |
| handle_property_set(socket, name, value, false); |
| break; |
| } |
| |
| default: |
| LOG(ERROR) << "sys_prop: invalid command " << cmd; |
| socket.SendUint32(PROP_ERROR_INVALID_CMD); |
| break; |
| } |
| } |
| |
| static void load_properties_from_file(const char *, const char *); |
| |
| /* |
| * Filter is used to decide which properties to load: NULL loads all keys, |
| * "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match. |
| */ |
| static void load_properties(char *data, const char *filter) |
| { |
| char *key, *value, *eol, *sol, *tmp, *fn; |
| size_t flen = 0; |
| |
| if (filter) { |
| flen = strlen(filter); |
| } |
| |
| sol = data; |
| while ((eol = strchr(sol, '\n'))) { |
| key = sol; |
| *eol++ = 0; |
| sol = eol; |
| |
| while (isspace(*key)) key++; |
| if (*key == '#') continue; |
| |
| tmp = eol - 2; |
| while ((tmp > key) && isspace(*tmp)) *tmp-- = 0; |
| |
| if (!strncmp(key, "import ", 7) && flen == 0) { |
| fn = key + 7; |
| while (isspace(*fn)) fn++; |
| |
| key = strchr(fn, ' '); |
| if (key) { |
| *key++ = 0; |
| while (isspace(*key)) key++; |
| } |
| |
| load_properties_from_file(fn, key); |
| |
| } else { |
| value = strchr(key, '='); |
| if (!value) continue; |
| *value++ = 0; |
| |
| tmp = value - 2; |
| while ((tmp > key) && isspace(*tmp)) *tmp-- = 0; |
| |
| while (isspace(*value)) value++; |
| |
| if (flen > 0) { |
| if (filter[flen - 1] == '*') { |
| if (strncmp(key, filter, flen - 1)) continue; |
| } else { |
| if (strcmp(key, filter)) continue; |
| } |
| } |
| |
| property_set(key, value); |
| } |
| } |
| } |
| |
| // Filter is used to decide which properties to load: NULL loads all keys, |
| // "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match. |
| static void load_properties_from_file(const char* filename, const char* filter) { |
| Timer t; |
| std::string data; |
| if (!read_file(filename, &data)) { |
| PLOG(WARNING) << "Couldn't load properties from " << filename; |
| return; |
| } |
| data.push_back('\n'); |
| load_properties(&data[0], filter); |
| LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)"; |
| } |
| |
| static void load_persistent_properties() { |
| persistent_properties_loaded = 1; |
| |
| std::unique_ptr<DIR, int(*)(DIR*)> dir(opendir(PERSISTENT_PROPERTY_DIR), closedir); |
| if (!dir) { |
| PLOG(ERROR) << "Unable to open persistent property directory \"" |
| << PERSISTENT_PROPERTY_DIR << "\""; |
| return; |
| } |
| |
| struct dirent* entry; |
| while ((entry = readdir(dir.get())) != NULL) { |
| if (strncmp("persist.", entry->d_name, strlen("persist."))) { |
| continue; |
| } |
| if (entry->d_type != DT_REG) { |
| continue; |
| } |
| |
| // Open the file and read the property value. |
| int fd = openat(dirfd(dir.get()), entry->d_name, O_RDONLY | O_NOFOLLOW); |
| if (fd == -1) { |
| PLOG(ERROR) << "Unable to open persistent property file \"" << entry->d_name << "\""; |
| continue; |
| } |
| |
| struct stat sb; |
| if (fstat(fd, &sb) == -1) { |
| PLOG(ERROR) << "fstat on property file \"" << entry->d_name << "\" failed"; |
| 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) { |
| PLOG(ERROR) << "skipping insecure property file " << entry->d_name |
| << " (uid=" << sb.st_uid << " gid=" << sb.st_gid |
| << " nlink=" << sb.st_nlink << " mode=" << std::oct << sb.st_mode << ")"; |
| close(fd); |
| continue; |
| } |
| |
| char value[PROP_VALUE_MAX]; |
| int length = read(fd, value, sizeof(value) - 1); |
| if (length >= 0) { |
| value[length] = 0; |
| property_set(entry->d_name, value); |
| } else { |
| PLOG(ERROR) << "Unable to read persistent property file " << entry->d_name; |
| } |
| close(fd); |
| } |
| } |
| |
| void property_load_boot_defaults() { |
| load_properties_from_file("/default.prop", NULL); |
| load_properties_from_file("/odm/default.prop", NULL); |
| load_properties_from_file("/vendor/default.prop", NULL); |
| } |
| |
| static void load_override_properties() { |
| if (ALLOW_LOCAL_PROP_OVERRIDE) { |
| load_properties_from_file("/data/local.prop", NULL); |
| } |
| } |
| |
| /* 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(); |
| property_set("ro.persistent_properties.ready", "true"); |
| } |
| |
| void load_recovery_id_prop() { |
| std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(), |
| fs_mgr_free_fstab); |
| if (!fstab) { |
| PLOG(ERROR) << "unable to read default fstab"; |
| return; |
| } |
| |
| fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab.get(), RECOVERY_MOUNT_POINT); |
| if (rec == NULL) { |
| LOG(ERROR) << "/recovery not specified in fstab"; |
| return; |
| } |
| |
| int fd = open(rec->blk_device, O_RDONLY); |
| if (fd == -1) { |
| PLOG(ERROR) << "error opening block device " << rec->blk_device; |
| return; |
| } |
| |
| boot_img_hdr hdr; |
| if (android::base::ReadFully(fd, &hdr, sizeof(hdr))) { |
| std::string hex = bytes_to_hex(reinterpret_cast<uint8_t*>(hdr.id), sizeof(hdr.id)); |
| property_set("ro.recovery_id", hex.c_str()); |
| } else { |
| PLOG(ERROR) << "error reading /recovery"; |
| } |
| |
| close(fd); |
| } |
| |
| void load_system_props() { |
| load_properties_from_file("/system/build.prop", NULL); |
| load_properties_from_file("/odm/build.prop", NULL); |
| load_properties_from_file("/vendor/build.prop", NULL); |
| load_properties_from_file("/factory/factory.prop", "ro.*"); |
| load_recovery_id_prop(); |
| } |
| |
| void start_property_service() { |
| property_set("ro.property_service.version", "2"); |
| |
| property_set_fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, |
| 0666, 0, 0, NULL); |
| if (property_set_fd == -1) { |
| PLOG(ERROR) << "start_property_service socket creation failed"; |
| exit(1); |
| } |
| |
| listen(property_set_fd, 8); |
| |
| register_epoll_handler(property_set_fd, handle_property_set_fd); |
| } |