diff options
Diffstat (limited to 'src/home/homed-manager.c')
| -rw-r--r-- | src/home/homed-manager.c | 2224 |
1 files changed, 2224 insertions, 0 deletions
diff --git a/src/home/homed-manager.c b/src/home/homed-manager.c new file mode 100644 index 0000000..c452531 --- /dev/null +++ b/src/home/homed-manager.c @@ -0,0 +1,2224 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <grp.h> +#include <linux/fs.h> +#include <linux/magic.h> +#include <math.h> +#include <openssl/pem.h> +#include <pwd.h> +#include <sys/ioctl.h> +#include <sys/quota.h> +#include <sys/stat.h> + +#include "sd-id128.h" + +#include "btrfs-util.h" +#include "bus-common-errors.h" +#include "bus-error.h" +#include "bus-log-control-api.h" +#include "bus-polkit.h" +#include "clean-ipc.h" +#include "common-signal.h" +#include "conf-files.h" +#include "device-util.h" +#include "dirent-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "format-util.h" +#include "fs-util.h" +#include "glyph-util.h" +#include "gpt.h" +#include "home-util.h" +#include "homed-conf.h" +#include "homed-home-bus.h" +#include "homed-home.h" +#include "homed-manager-bus.h" +#include "homed-manager.h" +#include "homed-varlink.h" +#include "io-util.h" +#include "mkdir.h" +#include "openssl-util.h" +#include "process-util.h" +#include "quota-util.h" +#include "random-util.h" +#include "resize-fs.h" +#include "socket-util.h" +#include "sort-util.h" +#include "stat-util.h" +#include "strv.h" +#include "sync-util.h" +#include "tmpfile-util.h" +#include "udev-util.h" +#include "user-record-sign.h" +#include "user-record-util.h" +#include "user-record.h" +#include "user-util.h" +#include "varlink-io.systemd.UserDatabase.h" + +/* Where to look for private/public keys that are used to sign the user records. We are not using + * CONF_PATHS_NULSTR() here since we want to insert /var/lib/systemd/home/ in the middle. And we insert that + * since we want to auto-generate a persistent private/public key pair if we need to. */ +#define KEY_PATHS_NULSTR \ + "/etc/systemd/home/\0" \ + "/run/systemd/home/\0" \ + "/var/lib/systemd/home/\0" \ + "/usr/local/lib/systemd/home/\0" \ + "/usr/lib/systemd/home/\0" + +static bool uid_is_home(uid_t uid) { + return uid >= HOME_UID_MIN && uid <= HOME_UID_MAX; +} +/* Takes a value generated randomly or by hashing and turns it into a UID in the right range */ + +#define UID_CLAMP_INTO_HOME_RANGE(rnd) (((uid_t) (rnd) % (HOME_UID_MAX - HOME_UID_MIN + 1)) + HOME_UID_MIN) + +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(homes_by_uid_hash_ops, void, trivial_hash_func, trivial_compare_func, Home, home_free); +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(homes_by_name_hash_ops, char, string_hash_func, string_compare_func, Home, home_free); +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(homes_by_worker_pid_hash_ops, void, trivial_hash_func, trivial_compare_func, Home, home_free); +DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(homes_by_sysfs_hash_ops, char, path_hash_func, path_compare, Home, home_free); + +static int on_home_inotify(sd_event_source *s, const struct inotify_event *event, void *userdata); +static int manager_gc_images(Manager *m); +static int manager_enumerate_images(Manager *m); +static int manager_assess_image(Manager *m, int dir_fd, const char *dir_path, const char *dentry_name); +static void manager_revalidate_image(Manager *m, Home *h); + +static void manager_watch_home(Manager *m) { + struct statfs sfs; + int r; + + assert(m); + + m->inotify_event_source = sd_event_source_disable_unref(m->inotify_event_source); + m->scan_slash_home = false; + + if (statfs(get_home_root(), &sfs) < 0) { + log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno, + "Failed to statfs() %s directory, disabling automatic scanning.", get_home_root()); + return; + } + + if (is_network_fs(&sfs)) { + log_info("%s is a network file system, disabling automatic scanning.", get_home_root()); + return; + } + + if (is_fs_type(&sfs, AUTOFS_SUPER_MAGIC)) { + log_info("%s is on autofs, disabling automatic scanning.", get_home_root()); + return; + } + + m->scan_slash_home = true; + + r = sd_event_add_inotify(m->event, &m->inotify_event_source, get_home_root(), + IN_CREATE|IN_CLOSE_WRITE|IN_DELETE_SELF|IN_MOVE_SELF|IN_ONLYDIR|IN_MOVED_TO|IN_MOVED_FROM|IN_DELETE, + on_home_inotify, m); + if (r < 0) + log_full_errno(r == -ENOENT ? LOG_DEBUG : LOG_WARNING, r, + "Failed to create inotify watch on %s, ignoring.", get_home_root()); + + (void) sd_event_source_set_description(m->inotify_event_source, "home-inotify"); + + log_info("Watching %s.", get_home_root()); +} + +static int on_home_inotify(sd_event_source *s, const struct inotify_event *event, void *userdata) { + _cleanup_free_ char *j = NULL; + Manager *m = ASSERT_PTR(userdata); + const char *e, *n; + + assert(event); + + if ((event->mask & (IN_Q_OVERFLOW|IN_MOVE_SELF|IN_DELETE_SELF|IN_IGNORED|IN_UNMOUNT)) != 0) { + + if (FLAGS_SET(event->mask, IN_Q_OVERFLOW)) + log_debug("%s inotify queue overflow, rescanning.", get_home_root()); + else if (FLAGS_SET(event->mask, IN_MOVE_SELF)) + log_info("%s moved or renamed, recreating watch and rescanning.", get_home_root()); + else if (FLAGS_SET(event->mask, IN_DELETE_SELF)) + log_info("%s deleted, recreating watch and rescanning.", get_home_root()); + else if (FLAGS_SET(event->mask, IN_UNMOUNT)) + log_info("%s unmounted, recreating watch and rescanning.", get_home_root()); + else if (FLAGS_SET(event->mask, IN_IGNORED)) + log_info("%s watch invalidated, recreating watch and rescanning.", get_home_root()); + + manager_watch_home(m); + (void) manager_gc_images(m); + (void) manager_enumerate_images(m); + (void) bus_manager_emit_auto_login_changed(m); + return 0; + } + + /* For the other inotify events, let's ignore all events for file names that don't match our + * expectations */ + if (isempty(event->name)) + return 0; + e = endswith(event->name, FLAGS_SET(event->mask, IN_ISDIR) ? ".homedir" : ".home"); + if (!e) + return 0; + + n = strndupa_safe(event->name, e - event->name); + if (!suitable_user_name(n)) + return 0; + + j = path_join(get_home_root(), event->name); + if (!j) + return log_oom(); + + if ((event->mask & (IN_CREATE|IN_CLOSE_WRITE|IN_MOVED_TO)) != 0) { + if (FLAGS_SET(event->mask, IN_CREATE)) + log_debug("%s has been created, having a look.", j); + else if (FLAGS_SET(event->mask, IN_CLOSE_WRITE)) + log_debug("%s has been modified, having a look.", j); + else if (FLAGS_SET(event->mask, IN_MOVED_TO)) + log_debug("%s has been moved in, having a look.", j); + + (void) manager_assess_image(m, -1, get_home_root(), event->name); + (void) bus_manager_emit_auto_login_changed(m); + } + + if ((event->mask & (IN_DELETE | IN_CLOSE_WRITE | IN_MOVED_FROM)) != 0) { + Home *h; + + if (FLAGS_SET(event->mask, IN_DELETE)) + log_debug("%s has been deleted, revalidating.", j); + else if (FLAGS_SET(event->mask, IN_CLOSE_WRITE)) + log_debug("%s has been closed after writing, revalidating.", j); + else if (FLAGS_SET(event->mask, IN_MOVED_FROM)) + log_debug("%s has been moved away, revalidating.", j); + + h = hashmap_get(m->homes_by_name, n); + if (h) { + manager_revalidate_image(m, h); + (void) bus_manager_emit_auto_login_changed(m); + } + } + + return 0; +} + +int manager_new(Manager **ret) { + _cleanup_(manager_freep) Manager *m = NULL; + int r; + + assert(ret); + + m = new(Manager, 1); + if (!m) + return -ENOMEM; + + *m = (Manager) { + .default_storage = _USER_STORAGE_INVALID, + .rebalance_interval_usec = 2 * USEC_PER_MINUTE, /* initially, rebalance every 2min */ + }; + + r = manager_parse_config_file(m); + if (r < 0) + return r; + + r = sd_event_default(&m->event); + if (r < 0) + return r; + + r = sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); + if (r < 0) + return r; + + r = sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); + if (r < 0) + return r; + + r = sd_event_add_memory_pressure(m->event, NULL, NULL, NULL); + if (r < 0) + log_full_errno(ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || (r == -EHOSTDOWN) ? LOG_DEBUG : LOG_WARNING, r, + "Failed to allocate memory pressure watch, ignoring: %m"); + + r = sd_event_add_signal(m->event, NULL, SIGRTMIN+18, sigrtmin18_handler, NULL); + if (r < 0) + return r; + + (void) sd_event_set_watchdog(m->event, true); + + m->homes_by_uid = hashmap_new(&homes_by_uid_hash_ops); + if (!m->homes_by_uid) + return -ENOMEM; + + m->homes_by_name = hashmap_new(&homes_by_name_hash_ops); + if (!m->homes_by_name) + return -ENOMEM; + + m->homes_by_worker_pid = hashmap_new(&homes_by_worker_pid_hash_ops); + if (!m->homes_by_worker_pid) + return -ENOMEM; + + m->homes_by_sysfs = hashmap_new(&homes_by_sysfs_hash_ops); + if (!m->homes_by_sysfs) + return -ENOMEM; + + *ret = TAKE_PTR(m); + return 0; +} + +Manager* manager_free(Manager *m) { + Home *h; + + assert(m); + + HASHMAP_FOREACH(h, m->homes_by_worker_pid) + (void) home_wait_for_worker(h); + + m->bus = sd_bus_flush_close_unref(m->bus); + m->polkit_registry = bus_verify_polkit_async_registry_free(m->polkit_registry); + + m->device_monitor = sd_device_monitor_unref(m->device_monitor); + + m->inotify_event_source = sd_event_source_unref(m->inotify_event_source); + m->notify_socket_event_source = sd_event_source_unref(m->notify_socket_event_source); + m->deferred_rescan_event_source = sd_event_source_unref(m->deferred_rescan_event_source); + m->deferred_gc_event_source = sd_event_source_unref(m->deferred_gc_event_source); + m->deferred_auto_login_event_source = sd_event_source_unref(m->deferred_auto_login_event_source); + m->rebalance_event_source = sd_event_source_unref(m->rebalance_event_source); + + m->event = sd_event_unref(m->event); + + m->homes_by_uid = hashmap_free(m->homes_by_uid); + m->homes_by_name = hashmap_free(m->homes_by_name); + m->homes_by_worker_pid = hashmap_free(m->homes_by_worker_pid); + m->homes_by_sysfs = hashmap_free(m->homes_by_sysfs); + + if (m->private_key) + EVP_PKEY_free(m->private_key); + + hashmap_free(m->public_keys); + + varlink_server_unref(m->varlink_server); + free(m->userdb_service); + + free(m->default_file_system_type); + + return mfree(m); +} + +int manager_verify_user_record(Manager *m, UserRecord *hr) { + EVP_PKEY *pkey; + int r; + + assert(m); + assert(hr); + + if (!m->private_key && hashmap_isempty(m->public_keys)) { + r = user_record_has_signature(hr); + if (r < 0) + return r; + + return r ? -ENOKEY : USER_RECORD_UNSIGNED; + } + + /* Is it our own? */ + if (m->private_key) { + r = user_record_verify(hr, m->private_key); + switch (r) { + + case USER_RECORD_FOREIGN: + /* This record is not signed by this key, but let's see below */ + break; + + case USER_RECORD_SIGNED: /* Signed by us, but also by others, let's propagate that */ + case USER_RECORD_SIGNED_EXCLUSIVE: /* Signed by us, and nothing else, ditto */ + case USER_RECORD_UNSIGNED: /* Not signed at all, ditto */ + default: + return r; + } + } + + HASHMAP_FOREACH(pkey, m->public_keys) { + r = user_record_verify(hr, pkey); + switch (r) { + + case USER_RECORD_FOREIGN: + /* This record is not signed by this key, but let's see our other keys */ + break; + + case USER_RECORD_SIGNED: /* It's signed by this key we are happy with, but which is not our own. */ + case USER_RECORD_SIGNED_EXCLUSIVE: + return USER_RECORD_FOREIGN; + + case USER_RECORD_UNSIGNED: /* It's not signed at all */ + default: + return r; + } + } + + return -ENOKEY; +} + +static int manager_add_home_by_record( + Manager *m, + const char *name, + int dir_fd, + const char *fname) { + + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + _cleanup_(user_record_unrefp) UserRecord *hr = NULL; + unsigned line, column; + int r, is_signed; + struct stat st; + Home *h; + + assert(m); + assert(name); + assert(fname); + + if (fstatat(dir_fd, fname, &st, 0) < 0) + return log_error_errno(errno, "Failed to stat identity record %s: %m", fname); + + if (!S_ISREG(st.st_mode)) { + log_debug("Identity record file %s is not a regular file, ignoring.", fname); + return 0; + } + + if (st.st_size == 0) + goto unlink_this_file; + + r = json_parse_file_at(NULL, dir_fd, fname, JSON_PARSE_SENSITIVE, &v, &line, &column); + if (r < 0) + return log_error_errno(r, "Failed to parse identity record at %s:%u%u: %m", fname, line, column); + + if (json_variant_is_blank_object(v)) + goto unlink_this_file; + + hr = user_record_new(); + if (!hr) + return log_oom(); + + r = user_record_load(hr, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_LOG|USER_RECORD_PERMISSIVE); + if (r < 0) + return r; + + if (!streq_ptr(hr->user_name, name)) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Identity's user name %s does not match file name %s, refusing.", + hr->user_name, name); + + is_signed = manager_verify_user_record(m, hr); + switch (is_signed) { + + case -ENOKEY: + return log_warning_errno(is_signed, "User record %s is not signed by any accepted key, ignoring.", fname); + case USER_RECORD_UNSIGNED: + return log_warning_errno(SYNTHETIC_ERRNO(EPERM), "User record %s is not signed at all, ignoring.", fname); + case USER_RECORD_SIGNED: + log_info("User record %s is signed by us (and others), accepting.", fname); + break; + case USER_RECORD_SIGNED_EXCLUSIVE: + log_info("User record %s is signed only by us, accepting.", fname); + break; + case USER_RECORD_FOREIGN: + log_info("User record %s is signed by registered key from others, accepting.", fname); + break; + default: + assert(is_signed < 0); + return log_error_errno(is_signed, "Failed to verify signature of user record in %s: %m", fname); + } + + h = hashmap_get(m->homes_by_name, name); + if (h) { + r = home_set_record(h, hr); + if (r < 0) + return log_error_errno(r, "Failed to update home record for %s: %m", name); + + /* If we acquired a record now for a previously unallocated entry, then reset the state. This + * makes sure home_get_state() will check for the availability of the image file dynamically + * in order to detect to distinguish HOME_INACTIVE and HOME_ABSENT. */ + if (h->state == HOME_UNFIXATED) + h->state = _HOME_STATE_INVALID; + } else { + r = home_new(m, hr, NULL, &h); + if (r < 0) + return log_error_errno(r, "Failed to allocate new home object: %m"); + + log_info("Added registered home for user %s.", hr->user_name); + } + + /* Only entries we exclusively signed are writable to us, hence remember the result */ + h->signed_locally = is_signed == USER_RECORD_SIGNED_EXCLUSIVE; + + return 1; + +unlink_this_file: + /* If this is an empty file, then let's just remove it. An empty file is not useful in any case, and + * apparently xfs likes to leave empty files around when not unmounted cleanly (see + * https://github.com/systemd/systemd/issues/15178 for example). Note that we don't delete non-empty + * files even if they are invalid, because that's just too risky, we might delete data the user still + * needs. But empty files are never useful, hence let's just remove them. */ + + if (unlinkat(dir_fd, fname, 0) < 0) + return log_error_errno(errno, "Failed to remove empty user record file %s: %m", fname); + + log_notice("Discovered empty user record file %s/%s, removed automatically.", home_record_dir(), fname); + return 0; +} + +static int manager_enumerate_records(Manager *m) { + _cleanup_closedir_ DIR *d = NULL; + + assert(m); + + d = opendir(home_record_dir()); + if (!d) + return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, + "Failed to open %s: %m", home_record_dir()); + + FOREACH_DIRENT(de, d, return log_error_errno(errno, "Failed to read record directory: %m")) { + _cleanup_free_ char *n = NULL; + const char *e; + + if (!dirent_is_file(de)) + continue; + + e = endswith(de->d_name, ".identity"); + if (!e) + continue; + + n = strndup(de->d_name, e - de->d_name); + if (!n) + return log_oom(); + + if (!suitable_user_name(n)) + continue; + + (void) manager_add_home_by_record(m, n, dirfd(d), de->d_name); + } + + return 0; +} + +static int search_quota(uid_t uid, const char *exclude_quota_path) { + struct stat exclude_st = {}; + dev_t previous_devno = 0; + int r; + + /* Checks whether the specified UID owns any files on the files system, but ignore any file system + * backing the specified file. The file is used when operating on home directories, where it's OK if + * the UID of them already owns files. */ + + if (exclude_quota_path && stat(exclude_quota_path, &exclude_st) < 0) { + if (errno != ENOENT) + return log_warning_errno(errno, "Failed to stat %s, ignoring: %m", exclude_quota_path); + } + + /* Check a few usual suspects where regular users might own files. Note that this is by no means + * comprehensive, but should cover most cases. Note that in an ideal world every user would be + * registered in NSS and avoid our own UID range, but for all other cases, it's a good idea to be + * paranoid and check quota if we can. */ + FOREACH_STRING(where, get_home_root(), "/tmp/", "/var/", "/var/mail/", "/var/tmp/", "/var/spool/") { + struct dqblk req; + struct stat st; + + if (stat(where, &st) < 0) { + log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, + "Failed to stat %s, ignoring: %m", where); + continue; + } + + if (major(st.st_dev) == 0) { + log_debug("Directory %s is not on a real block device, not checking quota for UID use.", where); + continue; + } + + if (st.st_dev == exclude_st.st_dev) { /* If an exclude path is specified, then ignore quota + * reported on the same block device as that path. */ + log_debug("Directory %s is where the home directory is located, not checking quota for UID use.", where); + continue; + } + + if (st.st_dev == previous_devno) { /* Does this directory have the same devno as the previous + * one we tested? If so, there's no point in testing this + * again. */ + log_debug("Directory %s is on same device as previous tested directory, not checking quota for UID use a second time.", where); + continue; + } + + previous_devno = st.st_dev; + + r = quotactl_devnum(QCMD_FIXED(Q_GETQUOTA, USRQUOTA), st.st_dev, uid, &req); + if (r < 0) { + if (ERRNO_IS_NOT_SUPPORTED(r)) + log_debug_errno(r, "No UID quota support on %s, ignoring.", where); + else if (ERRNO_IS_PRIVILEGE(r)) + log_debug_errno(r, "UID quota support for %s prohibited, ignoring.", where); + else + log_warning_errno(r, "Failed to query quota on %s, ignoring: %m", where); + + continue; + } + + if ((FLAGS_SET(req.dqb_valid, QIF_SPACE) && req.dqb_curspace > 0) || + (FLAGS_SET(req.dqb_valid, QIF_INODES) && req.dqb_curinodes > 0)) { + log_debug_errno(errno, "Quota reports UID " UID_FMT " occupies disk space on %s.", uid, where); + return 1; + } + } + + return 0; +} + +static int manager_acquire_uid( + Manager *m, + uid_t start_uid, + const char *user_name, + const char *exclude_quota_path, + uid_t *ret) { + + static const uint8_t hash_key[] = { + 0xa3, 0xb8, 0x82, 0x69, 0x9a, 0x71, 0xf7, 0xa9, + 0xe0, 0x7c, 0xf6, 0xf1, 0x21, 0x69, 0xd2, 0x1e + }; + + enum { + PHASE_SUGGESTED, + PHASE_HASHED, + PHASE_RANDOM + } phase = PHASE_SUGGESTED; + + unsigned n_tries = 100; + int r; + + assert(m); + assert(ret); + + for (;;) { + struct passwd *pw; + struct group *gr; + uid_t candidate; + Home *other; + + if (--n_tries <= 0) + return -EBUSY; + + switch (phase) { + + case PHASE_SUGGESTED: + phase = PHASE_HASHED; + + if (!uid_is_home(start_uid)) + continue; + + candidate = start_uid; + break; + + case PHASE_HASHED: + phase = PHASE_RANDOM; + + if (!user_name) + continue; + + candidate = UID_CLAMP_INTO_HOME_RANGE(siphash24(user_name, strlen(user_name), hash_key)); + break; + + case PHASE_RANDOM: + random_bytes(&candidate, sizeof(candidate)); + candidate = UID_CLAMP_INTO_HOME_RANGE(candidate); + break; + + default: + assert_not_reached(); + } + + other = hashmap_get(m->homes_by_uid, UID_TO_PTR(candidate)); + if (other) { + log_debug("Candidate UID " UID_FMT " already used by another home directory (%s), let's try another.", + candidate, other->user_name); + continue; + } + + pw = getpwuid(candidate); + if (pw) { + log_debug("Candidate UID " UID_FMT " already registered by another user in NSS (%s), let's try another.", + candidate, pw->pw_name); + continue; + } + + gr = getgrgid((gid_t) candidate); + if (gr) { + log_debug("Candidate UID " UID_FMT " already registered by another group in NSS (%s), let's try another.", + candidate, gr->gr_name); + continue; + } + + r = search_ipc(candidate, (gid_t) candidate); + if (r < 0) + continue; + if (r > 0) { + log_debug_errno(r, "Candidate UID " UID_FMT " already owns IPC objects, let's try another: %m", + candidate); + continue; + } + + r = search_quota(candidate, exclude_quota_path); + if (r != 0) + continue; + + *ret = candidate; + return 0; + } +} + +static int manager_add_home_by_image( + Manager *m, + const char *user_name, + const char *realm, + const char *image_path, + const char *sysfs, + UserStorage storage, + uid_t start_uid) { + + _cleanup_(user_record_unrefp) UserRecord *hr = NULL; + uid_t uid; + Home *h; + int r; + + assert(m); + + assert(m); + assert(user_name); + assert(image_path); + assert(storage >= 0); + assert(storage < _USER_STORAGE_MAX); + + h = hashmap_get(m->homes_by_name, user_name); + if (h) { + bool same; + + if (h->state != HOME_UNFIXATED) { + log_debug("Found an image for user %s which already has a record, skipping.", user_name); + return 0; /* ignore images that synthesize a user we already have a record for */ + } + + same = user_record_storage(h->record) == storage; + if (same) { + if (h->sysfs && sysfs) + same = path_equal(h->sysfs, sysfs); + else if (!!h->sysfs != !!sysfs) + same = false; + else { + const char *p; + + p = user_record_image_path(h->record); + same = p && path_equal(p, image_path); + } + } + + if (!same) { + log_debug("Found multiple images for user '%s', ignoring image '%s'.", user_name, image_path); + return 0; + } + } else { + /* Check NSS, in case there's another user or group by this name */ + if (getpwnam(user_name) || getgrnam(user_name)) { + log_debug("Found an existing user or group by name '%s', ignoring image '%s'.", user_name, image_path); + return 0; + } + } + + if (h && uid_is_valid(h->uid)) + uid = h->uid; + else { + r = manager_acquire_uid(m, start_uid, user_name, + IN_SET(storage, USER_SUBVOLUME, USER_DIRECTORY, USER_FSCRYPT) ? image_path : NULL, + &uid); + if (r < 0) + return log_warning_errno(r, "Failed to acquire unused UID for %s: %m", user_name); + } + + hr = user_record_new(); + if (!hr) + return log_oom(); + + r = user_record_synthesize(hr, user_name, realm, image_path, storage, uid, (gid_t) uid); + if (r < 0) + return log_error_errno(r, "Failed to synthesize home record for %s (image %s): %m", user_name, image_path); + + if (h) { + r = home_set_record(h, hr); + if (r < 0) + return log_error_errno(r, "Failed to update home record for %s: %m", user_name); + } else { + r = home_new(m, hr, sysfs, &h); + if (r < 0) + return log_error_errno(r, "Failed to allocate new home object: %m"); + + h->state = HOME_UNFIXATED; + + log_info("Discovered new home for user %s through image %s.", user_name, image_path); + } + + return 1; +} + +int manager_augment_record_with_uid( + Manager *m, + UserRecord *hr) { + + const char *exclude_quota_path = NULL; + uid_t start_uid = UID_INVALID, uid; + int r; + + assert(m); + assert(hr); + + if (uid_is_valid(hr->uid)) + return 0; + + if (IN_SET(hr->storage, USER_CLASSIC, USER_SUBVOLUME, USER_DIRECTORY, USER_FSCRYPT)) { + const char * ip; + + ip = user_record_image_path(hr); + if (ip) { + struct stat st; + + if (stat(ip, &st) < 0) { + if (errno != ENOENT) + log_warning_errno(errno, "Failed to stat(%s): %m", ip); + } else if (uid_is_home(st.st_uid)) { + start_uid = st.st_uid; + exclude_quota_path = ip; + } + } + } + + r = manager_acquire_uid(m, start_uid, hr->user_name, exclude_quota_path, &uid); + if (r < 0) + return r; + + log_debug("Acquired new UID " UID_FMT " for %s.", uid, hr->user_name); + + r = user_record_add_binding( + hr, + _USER_STORAGE_INVALID, + NULL, + SD_ID128_NULL, + SD_ID128_NULL, + SD_ID128_NULL, + NULL, + NULL, + UINT64_MAX, + NULL, + NULL, + uid, + (gid_t) uid); + if (r < 0) + return r; + + return 1; +} + +static int manager_assess_image( + Manager *m, + int dir_fd, + const char *dir_path, + const char *dentry_name) { + + char *luks_suffix, *directory_suffix; + _cleanup_free_ char *path = NULL; + struct stat st; + int r; + + assert(m); + assert(dir_path); + assert(dentry_name); + + luks_suffix = endswith(dentry_name, ".home"); + if (luks_suffix) + directory_suffix = NULL; + else + directory_suffix = endswith(dentry_name, ".homedir"); + + /* Early filter out: by name */ + if (!luks_suffix && !directory_suffix) + return 0; + + path = path_join(dir_path, dentry_name); + if (!path) + return log_oom(); + + /* Follow symlinks here, to allow people to link in stuff to make them available locally. */ + if (dir_fd >= 0) + r = fstatat(dir_fd, dentry_name, &st, 0); + else + r = stat(path, &st); + if (r < 0) + return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno, + "Failed to stat() directory entry '%s', ignoring: %m", dentry_name); + + if (S_ISREG(st.st_mode)) { + _cleanup_free_ char *n = NULL, *user_name = NULL, *realm = NULL; + + if (!luks_suffix) + return 0; + + n = strndup(dentry_name, luks_suffix - dentry_name); + if (!n) + return log_oom(); + + r = split_user_name_realm(n, &user_name, &realm); + if (r == -EINVAL) /* Not the right format: ignore */ + return 0; + if (r < 0) + return log_error_errno(r, "Failed to split image name into user name/realm: %m"); + + return manager_add_home_by_image(m, user_name, realm, path, NULL, USER_LUKS, UID_INVALID); + } + + if (S_ISDIR(st.st_mode)) { + _cleanup_free_ char *n = NULL, *user_name = NULL, *realm = NULL; + _cleanup_close_ int fd = -EBADF; + UserStorage storage; + + if (!directory_suffix) + return 0; + + n = strndup(dentry_name, directory_suffix - dentry_name); + if (!n) + return log_oom(); + + r = split_user_name_realm(n, &user_name, &realm); + if (r == -EINVAL) /* Not the right format: ignore */ + return 0; + if (r < 0) + return log_error_errno(r, "Failed to split image name into user name/realm: %m"); + + if (dir_fd >= 0) + fd = openat(dir_fd, dentry_name, O_DIRECTORY|O_RDONLY|O_CLOEXEC); + else + fd = open(path, O_DIRECTORY|O_RDONLY|O_CLOEXEC); + if (fd < 0) + return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_WARNING, errno, + "Failed to open directory '%s', ignoring: %m", path); + + if (fstat(fd, &st) < 0) + return log_warning_errno(errno, "Failed to fstat() %s, ignoring: %m", path); + + assert(S_ISDIR(st.st_mode)); /* Must hold, we used O_DIRECTORY above */ + + r = btrfs_is_subvol_fd(fd); + if (r < 0) + return log_warning_errno(errno, "Failed to determine whether %s is a btrfs subvolume: %m", path); + if (r > 0) + storage = USER_SUBVOLUME; + else { + struct fscrypt_policy policy; + + if (ioctl(fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) { + + if (errno == ENODATA) + log_debug_errno(errno, "Determined %s is not fscrypt encrypted.", path); + else if (ERRNO_IS_NOT_SUPPORTED(errno)) + log_debug_errno(errno, "Determined %s is not fscrypt encrypted because kernel or file system doesn't support it.", path); + else + log_debug_errno(errno, "FS_IOC_GET_ENCRYPTION_POLICY failed with unexpected error code on %s, ignoring: %m", path); + + storage = USER_DIRECTORY; + } else + storage = USER_FSCRYPT; + } + + return manager_add_home_by_image(m, user_name, realm, path, NULL, storage, st.st_uid); + } + + return 0; +} + +int manager_enumerate_images(Manager *m) { + _cleanup_closedir_ DIR *d = NULL; + + assert(m); + + if (!m->scan_slash_home) + return 0; + + d = opendir(get_home_root()); + if (!d) + return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, + "Failed to open %s: %m", get_home_root()); + + FOREACH_DIRENT(de, d, return log_error_errno(errno, "Failed to read %s directory: %m", get_home_root())) + (void) manager_assess_image(m, dirfd(d), get_home_root(), de->d_name); + + return 0; +} + +static int manager_connect_bus(Manager *m) { + _cleanup_free_ char *b = NULL; + const char *suffix, *busname; + int r; + + assert(m); + assert(!m->bus); + + r = sd_bus_default_system(&m->bus); + if (r < 0) + return log_error_errno(r, "Failed to connect to system bus: %m"); + + r = bus_add_implementation(m->bus, &manager_object, m); + if (r < 0) + return r; + + r = bus_log_control_api_register(m->bus); + if (r < 0) + return r; + + suffix = getenv("SYSTEMD_HOME_DEBUG_SUFFIX"); + if (suffix) { + b = strjoin("org.freedesktop.home1.", suffix); + if (!b) + return log_oom(); + busname = b; + } else + busname = "org.freedesktop.home1"; + + r = sd_bus_request_name_async(m->bus, NULL, busname, 0, NULL, NULL); + if (r < 0) + return log_error_errno(r, "Failed to request name: %m"); + + r = sd_bus_attach_event(m->bus, m->event, 0); + if (r < 0) + return log_error_errno(r, "Failed to attach bus to event loop: %m"); + + (void) sd_bus_set_exit_on_disconnect(m->bus, true); + + return 0; +} + +static int manager_bind_varlink(Manager *m) { + _cleanup_free_ char *p = NULL; + const char *suffix, *socket_path; + int r; + + assert(m); + assert(!m->varlink_server); + + r = varlink_server_new(&m->varlink_server, VARLINK_SERVER_ACCOUNT_UID|VARLINK_SERVER_INHERIT_USERDATA); + if (r < 0) + return log_error_errno(r, "Failed to allocate varlink server object: %m"); + + varlink_server_set_userdata(m->varlink_server, m); + + r = varlink_server_add_interface(m->varlink_server, &vl_interface_io_systemd_UserDatabase); + if (r < 0) + return log_error_errno(r, "Failed to add UserDatabase interface to varlink server: %m"); + + r = varlink_server_bind_method_many( + m->varlink_server, + "io.systemd.UserDatabase.GetUserRecord", vl_method_get_user_record, + "io.systemd.UserDatabase.GetGroupRecord", vl_method_get_group_record, + "io.systemd.UserDatabase.GetMemberships", vl_method_get_memberships); + if (r < 0) + return log_error_errno(r, "Failed to register varlink methods: %m"); + + (void) mkdir_p("/run/systemd/userdb", 0755); + + /* To make things easier to debug, when working from a homed managed home directory, let's optionally + * use a different varlink socket name */ + suffix = getenv("SYSTEMD_HOME_DEBUG_SUFFIX"); + if (suffix) { + p = strjoin("/run/systemd/userdb/io.systemd.Home.", suffix); + if (!p) + return log_oom(); + socket_path = p; + } else + socket_path = "/run/systemd/userdb/io.systemd.Home"; + + r = varlink_server_listen_address(m->varlink_server, socket_path, 0666); + if (r < 0) + return log_error_errno(r, "Failed to bind to varlink socket: %m"); + + r = varlink_server_attach_event(m->varlink_server, m->event, SD_EVENT_PRIORITY_NORMAL); + if (r < 0) + return log_error_errno(r, "Failed to attach varlink connection to event loop: %m"); + + assert(!m->userdb_service); + r = path_extract_filename(socket_path, &m->userdb_service); + if (r < 0) + return log_error_errno(r, "Failed to extra filename from socket path '%s': %m", socket_path); + + /* Avoid recursion */ + if (setenv("SYSTEMD_BYPASS_USERDB", m->userdb_service, 1) < 0) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to set $SYSTEMD_BYPASS_USERDB: %m"); + + return 0; +} + +static ssize_t read_datagram( + int fd, + struct ucred *ret_sender, + void **ret, + int *ret_passed_fd) { + + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + CMSG_SPACE(sizeof(int))) control; + _cleanup_free_ void *buffer = NULL; + _cleanup_close_ int passed_fd = -EBADF; + struct ucred *sender = NULL; + struct cmsghdr *cmsg; + struct msghdr mh; + struct iovec iov; + ssize_t n, m; + + assert(fd >= 0); + assert(ret_sender); + assert(ret); + assert(ret_passed_fd); + + n = next_datagram_size_fd(fd); + if (n < 0) + return n; + + buffer = malloc(n + 2); + if (!buffer) + return -ENOMEM; + + /* Pass one extra byte, as a size check */ + iov = IOVEC_MAKE(buffer, n + 1); + + mh = (struct msghdr) { + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_control = &control, + .msg_controllen = sizeof(control), + }; + + m = recvmsg_safe(fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC); + if (m < 0) + return m; + + /* Ensure the size matches what we determined before */ + if (m != n) { + cmsg_close_all(&mh); + return -EMSGSIZE; + } + + CMSG_FOREACH(cmsg, &mh) { + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_CREDENTIALS && + cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) { + assert(!sender); + sender = CMSG_TYPED_DATA(cmsg, struct ucred); + } + + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SCM_RIGHTS) { + + if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) { + cmsg_close_all(&mh); + return -EMSGSIZE; + } + + assert(passed_fd < 0); + passed_fd = *CMSG_TYPED_DATA(cmsg, int); + } + } + + if (sender) + *ret_sender = *sender; + else + *ret_sender = (struct ucred) UCRED_INVALID; + + *ret_passed_fd = TAKE_FD(passed_fd); + + /* For safety reasons: let's always NUL terminate. */ + ((char*) buffer)[n] = 0; + *ret = TAKE_PTR(buffer); + + return 0; +} + +static int on_notify_socket(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_strv_free_ char **l = NULL; + _cleanup_free_ void *datagram = NULL; + _cleanup_close_ int passed_fd = -EBADF; + struct ucred sender = UCRED_INVALID; + Manager *m = ASSERT_PTR(userdata); + ssize_t n; + Home *h; + + assert(s); + + n = read_datagram(fd, &sender, &datagram, &passed_fd); + if (n < 0) { + if (ERRNO_IS_TRANSIENT(n)) + return 0; + return log_error_errno(n, "Failed to read notify datagram: %m"); + } + + if (sender.pid <= 0) { + log_warning("Received notify datagram without valid sender PID, ignoring."); + return 0; + } + + h = hashmap_get(m->homes_by_worker_pid, PID_TO_PTR(sender.pid)); + if (!h) { + log_warning("Received notify datagram of unknown process, ignoring."); + return 0; + } + + l = strv_split(datagram, "\n"); + if (!l) + return log_oom(); + + home_process_notify(h, l, TAKE_FD(passed_fd)); + return 0; +} + +static int manager_listen_notify(Manager *m) { + _cleanup_close_ int fd = -EBADF; + union sockaddr_union sa = { + .un.sun_family = AF_UNIX, + .un.sun_path = "/run/systemd/home/notify", + }; + const char *suffix; + int r; + + assert(m); + assert(!m->notify_socket_event_source); + + suffix = getenv("SYSTEMD_HOME_DEBUG_SUFFIX"); + if (suffix) { + _cleanup_free_ char *unix_path = NULL; + + unix_path = strjoin("/run/systemd/home/notify.", suffix); + if (!unix_path) + return log_oom(); + r = sockaddr_un_set_path(&sa.un, unix_path); + if (r < 0) + return log_error_errno(r, "Socket path %s does not fit in sockaddr_un: %m", unix_path); + } + + fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (fd < 0) + return log_error_errno(errno, "Failed to create listening socket: %m"); + + (void) mkdir_parents(sa.un.sun_path, 0755); + (void) sockaddr_un_unlink(&sa.un); + + if (bind(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0) + return log_error_errno(errno, "Failed to bind to socket: %m"); + + r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true); + if (r < 0) + return r; + + r = sd_event_add_io(m->event, &m->notify_socket_event_source, fd, EPOLLIN, on_notify_socket, m); + if (r < 0) + return log_error_errno(r, "Failed to allocate event source for notify socket: %m"); + + (void) sd_event_source_set_description(m->notify_socket_event_source, "notify-socket"); + + /* Make sure we process sd_notify() before SIGCHLD for any worker, so that we always know the error + * number of a client before it exits. */ + r = sd_event_source_set_priority(m->notify_socket_event_source, SD_EVENT_PRIORITY_NORMAL - 5); + if (r < 0) + return log_error_errno(r, "Failed to alter priority of NOTIFY_SOCKET event source: %m"); + + r = sd_event_source_set_io_fd_own(m->notify_socket_event_source, true); + if (r < 0) + return log_error_errno(r, "Failed to pass ownership of notify socket: %m"); + + return TAKE_FD(fd); +} + +static int manager_add_device(Manager *m, sd_device *d) { + _cleanup_free_ char *user_name = NULL, *realm = NULL, *node = NULL; + const char *tabletype, *parttype, *partname, *partuuid, *sysfs; + sd_id128_t id; + int r; + + assert(m); + assert(d); + + r = sd_device_get_syspath(d, &sysfs); + if (r < 0) + return log_error_errno(r, "Failed to acquire sysfs path of device: %m"); + + r = sd_device_get_property_value(d, "ID_PART_TABLE_TYPE", &tabletype); + if (r == -ENOENT) + return 0; + if (r < 0) + return log_error_errno(r, "Failed to acquire ID_PART_TABLE_TYPE device property, ignoring: %m"); + + if (!streq(tabletype, "gpt")) { + log_debug("Found partition (%s) on non-GPT table, ignoring.", sysfs); + return 0; + } + + r = sd_device_get_property_value(d, "ID_PART_ENTRY_TYPE", &parttype); + if (r == -ENOENT) + return 0; + if (r < 0) + return log_error_errno(r, "Failed to acquire ID_PART_ENTRY_TYPE device property, ignoring: %m"); + if (sd_id128_string_equal(parttype, SD_GPT_USER_HOME) <= 0) { + log_debug("Found partition (%s) we don't care about, ignoring.", sysfs); + return 0; + } + + r = sd_device_get_property_value(d, "ID_PART_ENTRY_NAME", &partname); + if (r < 0) + return log_warning_errno(r, "Failed to acquire ID_PART_ENTRY_NAME device property, ignoring: %m"); + + r = split_user_name_realm(partname, &user_name, &realm); + if (r == -EINVAL) + return log_warning_errno(r, "Found partition with correct partition type but a non-parsable partition name '%s', ignoring.", partname); + if (r < 0) + return log_error_errno(r, "Failed to validate partition name '%s': %m", partname); + + r = sd_device_get_property_value(d, "ID_FS_UUID", &partuuid); + if (r < 0) + return log_warning_errno(r, "Failed to acquire ID_FS_UUID device property, ignoring: %m"); + + r = sd_id128_from_string(partuuid, &id); + if (r < 0) + return log_warning_errno(r, "Failed to parse ID_FS_UUID field '%s', ignoring: %m", partuuid); + + if (asprintf(&node, "/dev/disk/by-uuid/" SD_ID128_UUID_FORMAT_STR, SD_ID128_FORMAT_VAL(id)) < 0) + return log_oom(); + + return manager_add_home_by_image(m, user_name, realm, node, sysfs, USER_LUKS, UID_INVALID); +} + +static int manager_on_device(sd_device_monitor *monitor, sd_device *d, void *userdata) { + Manager *m = ASSERT_PTR(userdata); + int r; + + assert(d); + + if (device_for_action(d, SD_DEVICE_REMOVE)) { + const char *sysfs; + Home *h; + + r = sd_device_get_syspath(d, &sysfs); + if (r < 0) { + log_warning_errno(r, "Failed to acquire sysfs path from device: %m"); + return 0; + } + + log_info("block device %s has been removed.", sysfs); + + /* Let's see if we previously synthesized a home record from this device, if so, let's just + * revalidate that. Otherwise let's revalidate them all, but asynchronously. */ + h = hashmap_get(m->homes_by_sysfs, sysfs); + if (h) + manager_revalidate_image(m, h); + else + manager_enqueue_gc(m, NULL); + } else + (void) manager_add_device(m, d); + + (void) bus_manager_emit_auto_login_changed(m); + return 0; +} + +static int manager_watch_devices(Manager *m) { + int r; + + assert(m); + assert(!m->device_monitor); + + r = sd_device_monitor_new(&m->device_monitor); + if (r < 0) + return log_error_errno(r, "Failed to allocate device monitor: %m"); + + r = sd_device_monitor_filter_add_match_subsystem_devtype(m->device_monitor, "block", NULL); + if (r < 0) + return log_error_errno(r, "Failed to configure device monitor match: %m"); + + r = sd_device_monitor_attach_event(m->device_monitor, m->event); + if (r < 0) + return log_error_errno(r, "Failed to attach device monitor to event loop: %m"); + + r = sd_device_monitor_start(m->device_monitor, manager_on_device, m); + if (r < 0) + return log_error_errno(r, "Failed to start device monitor: %m"); + + return 0; +} + +static int manager_enumerate_devices(Manager *m) { + _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; + int r; + + assert(m); + + r = sd_device_enumerator_new(&e); + if (r < 0) + return r; + + r = sd_device_enumerator_add_match_subsystem(e, "block", true); + if (r < 0) + return r; + + FOREACH_DEVICE(e, d) + (void) manager_add_device(m, d); + + return 0; +} + +static int manager_load_key_pair(Manager *m) { + _cleanup_fclose_ FILE *f = NULL; + struct stat st; + int r; + + assert(m); + + if (m->private_key) { + EVP_PKEY_free(m->private_key); + m->private_key = NULL; + } + + r = search_and_fopen_nulstr("local.private", "re", NULL, KEY_PATHS_NULSTR, &f, NULL); + if (r == -ENOENT) + return 0; + if (r < 0) + return log_error_errno(r, "Failed to read private key file: %m"); + + if (fstat(fileno(f), &st) < 0) + return log_error_errno(errno, "Failed to stat private key file: %m"); + + r = stat_verify_regular(&st); + if (r < 0) + return log_error_errno(r, "Private key file is not regular: %m"); + + if (st.st_uid != 0 || (st.st_mode & 0077) != 0) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Private key file is readable by more than the root user"); + + m->private_key = PEM_read_PrivateKey(f, NULL, NULL, NULL); + if (!m->private_key) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to load private key pair"); + + log_info("Successfully loaded private key pair."); + + return 1; +} + +static int manager_generate_key_pair(Manager *m) { + _cleanup_(EVP_PKEY_CTX_freep) EVP_PKEY_CTX *ctx = NULL; + _cleanup_(unlink_and_freep) char *temp_public = NULL, *temp_private = NULL; + _cleanup_fclose_ FILE *fpublic = NULL, *fprivate = NULL; + int r; + + if (m->private_key) { + EVP_PKEY_free(m->private_key); + m->private_key = NULL; + } + + ctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL); + if (!ctx) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to allocate Ed25519 key generation context."); + + if (EVP_PKEY_keygen_init(ctx) <= 0) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to initialize Ed25519 key generation context."); + + log_info("Generating key pair for signing local user identity records."); + + if (EVP_PKEY_keygen(ctx, &m->private_key) <= 0) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to generate Ed25519 key pair"); + + log_info("Successfully created Ed25519 key pair."); + + (void) mkdir_p("/var/lib/systemd/home", 0755); + + /* Write out public key (note that we only do that as a help to the user, we don't make use of this ever */ + r = fopen_temporary("/var/lib/systemd/home/local.public", &fpublic, &temp_public); + if (r < 0) + return log_error_errno(errno, "Failed to open key file for writing: %m"); + + if (PEM_write_PUBKEY(fpublic, m->private_key) <= 0) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to write public key."); + + r = fflush_sync_and_check(fpublic); + if (r < 0) + return log_error_errno(r, "Failed to write private key: %m"); + + fpublic = safe_fclose(fpublic); + + /* Write out the private key (this actually writes out both private and public, OpenSSL is confusing) */ + r = fopen_temporary("/var/lib/systemd/home/local.private", &fprivate, &temp_private); + if (r < 0) + return log_error_errno(errno, "Failed to open key file for writing: %m"); + + if (PEM_write_PrivateKey(fprivate, m->private_key, NULL, NULL, 0, NULL, 0) <= 0) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to write private key pair."); + + r = fflush_sync_and_check(fprivate); + if (r < 0) + return log_error_errno(r, "Failed to write private key: %m"); + + fprivate = safe_fclose(fprivate); + + /* Both are written now, move them into place */ + + if (rename(temp_public, "/var/lib/systemd/home/local.public") < 0) + return log_error_errno(errno, "Failed to move public key file into place: %m"); + temp_public = mfree(temp_public); + + r = RET_NERRNO(rename(temp_private, "/var/lib/systemd/home/local.private")); + if (r < 0) { + (void) unlink("/var/lib/systemd/home/local.public"); /* try to remove the file we already created */ + return log_error_errno(r, "Failed to move private key file into place: %m"); + } + temp_private = mfree(temp_private); + + r = fsync_path_at(AT_FDCWD, "/var/lib/systemd/home/"); + if (r < 0) + log_warning_errno(r, "Failed to sync /var/lib/systemd/home/, ignoring: %m"); + + return 1; +} + +int manager_acquire_key_pair(Manager *m) { + int r; + + assert(m); + + /* Already there? */ + if (m->private_key) + return 1; + + /* First try to load key off disk */ + r = manager_load_key_pair(m); + if (r != 0) + return r; + + /* Didn't work, generate a new one */ + return manager_generate_key_pair(m); +} + +int manager_sign_user_record(Manager *m, UserRecord *u, UserRecord **ret, sd_bus_error *error) { + int r; + + assert(m); + assert(u); + assert(ret); + + r = manager_acquire_key_pair(m); + if (r < 0) + return r; + if (r == 0) + return sd_bus_error_set(error, BUS_ERROR_NO_PRIVATE_KEY, "Can't sign without local key."); + + return user_record_sign(u, m->private_key, ret); +} + +DEFINE_PRIVATE_HASH_OPS_FULL(public_key_hash_ops, char, string_hash_func, string_compare_func, free, EVP_PKEY, EVP_PKEY_free); + +static int manager_load_public_key_one(Manager *m, const char *path) { + _cleanup_(EVP_PKEY_freep) EVP_PKEY *pkey = NULL; + _cleanup_fclose_ FILE *f = NULL; + _cleanup_free_ char *fn = NULL; + struct stat st; + int r; + + assert(m); + + r = path_extract_filename(path, &fn); + if (r < 0) + return log_error_errno(r, "Failed to extract filename of path '%s': %m", path); + + if (streq(fn, "local.public")) /* we already loaded the private key, which includes the public one */ + return 0; + + f = fopen(path, "re"); + if (!f) { + if (errno == ENOENT) + return 0; + + return log_error_errno(errno, "Failed to open public key %s: %m", path); + } + + if (fstat(fileno(f), &st) < 0) + return log_error_errno(errno, "Failed to stat public key %s: %m", path); + + r = stat_verify_regular(&st); + if (r < 0) + return log_error_errno(r, "Public key file %s is not a regular file: %m", path); + + if (st.st_uid != 0 || (st.st_mode & 0022) != 0) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Public key file %s is writable by more than the root user, refusing.", path); + + r = hashmap_ensure_allocated(&m->public_keys, &public_key_hash_ops); + if (r < 0) + return log_oom(); + + pkey = PEM_read_PUBKEY(f, &pkey, NULL, NULL); + if (!pkey) + return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to parse public key file %s.", path); + + r = hashmap_put(m->public_keys, fn, pkey); + if (r < 0) + return log_error_errno(r, "Failed to add public key to set: %m"); + + TAKE_PTR(fn); + TAKE_PTR(pkey); + + return 0; +} + +static int manager_load_public_keys(Manager *m) { + _cleanup_strv_free_ char **files = NULL; + int r; + + assert(m); + + m->public_keys = hashmap_free(m->public_keys); + + r = conf_files_list_nulstr( + &files, + ".public", + NULL, + CONF_FILES_REGULAR|CONF_FILES_FILTER_MASKED, + KEY_PATHS_NULSTR); + if (r < 0) + return log_error_errno(r, "Failed to assemble list of public key directories: %m"); + + STRV_FOREACH(i, files) + (void) manager_load_public_key_one(m, *i); + + return 0; +} + +int manager_startup(Manager *m) { + int r; + + assert(m); + + r = manager_listen_notify(m); + if (r < 0) + return r; + + r = manager_connect_bus(m); + if (r < 0) + return r; + + r = manager_bind_varlink(m); + if (r < 0) + return r; + + r = manager_load_key_pair(m); /* only try to load it, don't generate any */ + if (r < 0) + return r; + + r = manager_load_public_keys(m); + if (r < 0) + return r; + + manager_watch_home(m); + (void) manager_watch_devices(m); + + (void) manager_enumerate_records(m); + (void) manager_enumerate_images(m); + (void) manager_enumerate_devices(m); + + /* Let's clean up home directories whose devices got removed while we were not running */ + (void) manager_enqueue_gc(m, NULL); + + return 0; +} + +void manager_revalidate_image(Manager *m, Home *h) { + int r; + + assert(m); + assert(h); + + /* Frees an automatically discovered image, if it's synthetic and its image disappeared. Unmounts any + * image if it's mounted but its image vanished. */ + + if (h->current_operation || !ordered_set_isempty(h->pending_operations)) + return; + + if (h->state == HOME_UNFIXATED) { + r = user_record_test_image_path(h->record); + if (r < 0) + log_warning_errno(r, "Can't determine if image of %s exists, freeing unfixated user: %m", h->user_name); + else if (r == USER_TEST_ABSENT) + log_info("Image for %s disappeared, freeing unfixated user.", h->user_name); + else + return; + + home_free(h); + + } else if (h->state < 0) { + + r = user_record_test_home_directory(h->record); + if (r < 0) { + log_warning_errno(r, "Unable to determine state of home directory, ignoring: %m"); + return; + } + + if (r == USER_TEST_MOUNTED) { + r = user_record_test_image_path(h->record); + if (r < 0) { + log_warning_errno(r, "Unable to determine state of image path, ignoring: %m"); + return; + } + + if (r == USER_TEST_ABSENT) { + _cleanup_(operation_unrefp) Operation *o = NULL; + + log_notice("Backing image disappeared while home directory %s was mounted, unmounting it forcibly.", h->user_name); + /* Wowza, the thing is mounted, but the device is gone? Act on it. */ + + r = home_killall(h); + if (r < 0) + log_warning_errno(r, "Failed to kill processes of user %s, ignoring: %m", h->user_name); + + /* We enqueue the operation here, after all the home directory might + * currently already run some operation, and we can deactivate it only after + * that's complete. */ + o = operation_new(OPERATION_DEACTIVATE_FORCE, NULL); + if (!o) { + log_oom(); + return; + } + + r = home_schedule_operation(h, o, NULL); + if (r < 0) + log_warning_errno(r, "Failed to enqueue forced home directory %s deactivation, ignoring: %m", h->user_name); + } + } + } +} + +int manager_gc_images(Manager *m) { + Home *h; + + assert_se(m); + + if (m->gc_focus) { + /* Focus on a specific home */ + + h = TAKE_PTR(m->gc_focus); + manager_revalidate_image(m, h); + } else { + /* Gc all */ + + HASHMAP_FOREACH(h, m->homes_by_name) + manager_revalidate_image(m, h); + } + + return 0; +} + +static int on_deferred_rescan(sd_event_source *s, void *userdata) { + Manager *m = ASSERT_PTR(userdata); + + m->deferred_rescan_event_source = sd_event_source_disable_unref(m->deferred_rescan_event_source); + + manager_enumerate_devices(m); + manager_enumerate_images(m); + return 0; +} + +int manager_enqueue_rescan(Manager *m) { + int r; + + assert(m); + + if (m->deferred_rescan_event_source) + return 0; + + if (!m->event) + return 0; + + if (IN_SET(sd_event_get_state(m->event), SD_EVENT_FINISHED, SD_EVENT_EXITING)) + return 0; + + r = sd_event_add_defer(m->event, &m->deferred_rescan_event_source, on_deferred_rescan, m); + if (r < 0) + return log_error_errno(r, "Failed to allocate rescan event source: %m"); + + r = sd_event_source_set_priority(m->deferred_rescan_event_source, SD_EVENT_PRIORITY_IDLE+1); + if (r < 0) + log_warning_errno(r, "Failed to tweak priority of event source, ignoring: %m"); + + (void) sd_event_source_set_description(m->deferred_rescan_event_source, "deferred-rescan"); + return 1; +} + +static int on_deferred_gc(sd_event_source *s, void *userdata) { + Manager *m = ASSERT_PTR(userdata); + + m->deferred_gc_event_source = sd_event_source_disable_unref(m->deferred_gc_event_source); + + manager_gc_images(m); + return 0; +} + +int manager_enqueue_gc(Manager *m, Home *focus) { + int r; + + assert(m); + + /* This enqueues a request to GC dead homes. It may be called with focus=NULL in which case all homes + * will be scanned, or with the parameter set, in which case only that home is checked. */ + + if (!m->event) + return 0; + + if (IN_SET(sd_event_get_state(m->event), SD_EVENT_FINISHED, SD_EVENT_EXITING)) + return 0; + + /* If a focus home is specified, then remember to focus just on this home. Otherwise invalidate any + * focus that might be set to look at all homes. */ + + if (m->deferred_gc_event_source) { + if (m->gc_focus != focus) /* not the same focus, then look at everything */ + m->gc_focus = NULL; + + return 0; + } else + m->gc_focus = focus; /* start focused */ + + r = sd_event_add_defer(m->event, &m->deferred_gc_event_source, on_deferred_gc, m); + if (r < 0) + return log_error_errno(r, "Failed to allocate GC event source: %m"); + + r = sd_event_source_set_priority(m->deferred_gc_event_source, SD_EVENT_PRIORITY_IDLE); + if (r < 0) + log_warning_errno(r, "Failed to tweak priority of event source, ignoring: %m"); + + (void) sd_event_source_set_description(m->deferred_gc_event_source, "deferred-gc"); + return 1; +} + +static bool manager_shall_rebalance(Manager *m) { + Home *h; + + assert(m); + + if (IN_SET(m->rebalance_state, REBALANCE_PENDING, REBALANCE_SHRINKING, REBALANCE_GROWING)) + return true; + + HASHMAP_FOREACH(h, m->homes_by_name) + if (home_shall_rebalance(h)) + return true; + + return false; +} + +static int home_cmp(Home *const*a, Home *const*b) { + int r; + + assert(a); + assert(*a); + assert(b); + assert(*b); + + /* Order user records by their weight (and by their name, to make things stable). We put the records + * with the highest weight last, since we distribute space from the beginning and round down, hence + * later entries tend to get slightly more than earlier entries. */ + + r = CMP(user_record_rebalance_weight((*a)->record), user_record_rebalance_weight((*b)->record)); + if (r != 0) + return r; + + return strcmp((*a)->user_name, (*b)->user_name); +} + +static int manager_rebalance_calculate(Manager *m) { + uint64_t weight_sum, free_sum, usage_sum = 0, min_free = UINT64_MAX; + _cleanup_free_ Home **array = NULL; + bool relevant = false; + struct statfs sfs; + int c = 0, r; + Home *h; + + assert(m); + + if (statfs(get_home_root(), &sfs) < 0) + return log_error_errno(errno, "Failed to statfs() /home: %m"); + + free_sum = (uint64_t) sfs.f_bsize * sfs.f_bavail; /* This much free space is available on the + * underlying pool directory */ + + weight_sum = REBALANCE_WEIGHT_BACKING; /* Grant the underlying pool directory a fixed weight of 20 + * (home dirs get 100 by default, i.e. 5x more). This weight + * is not configurable, the per-home weights are. */ + + HASHMAP_FOREACH(h, m->homes_by_name) { + statfs_f_type_t fstype; + h->rebalance_pending = false; /* First, reset the flag, we only want it to be true for the + * homes that qualify for rebalancing */ + + if (!home_shall_rebalance(h)) /* Only look at actual candidates */ + continue; + + if (home_is_busy(h)) + return -EBUSY; /* Let's not rebalance if there's a busy home directory. */ + + r = home_get_disk_status( + h, + &h->rebalance_size, + &h->rebalance_usage, + &h->rebalance_free, + NULL, + NULL, + &fstype, + NULL); + if (r < 0) { + log_warning_errno(r, "Failed to get free space of home '%s', ignoring.", h->user_name); + continue; + } + + if (h->rebalance_free > UINT64_MAX - free_sum) + return log_error_errno(SYNTHETIC_ERRNO(EOVERFLOW), "Rebalance free overflow"); + free_sum += h->rebalance_free; + + if (h->rebalance_usage > UINT64_MAX - usage_sum) + return log_error_errno(SYNTHETIC_ERRNO(EOVERFLOW), "Rebalance usage overflow"); + usage_sum += h->rebalance_usage; + + h->rebalance_weight = user_record_rebalance_weight(h->record); + if (h->rebalance_weight > UINT64_MAX - weight_sum) + return log_error_errno(SYNTHETIC_ERRNO(EOVERFLOW), "Rebalance weight overflow"); + weight_sum += h->rebalance_weight; + + h->rebalance_min = minimal_size_by_fs_magic(fstype); + + if (!GREEDY_REALLOC(array, c+1)) + return log_oom(); + + array[c++] = h; + } + + if (c == 0) { + log_debug("No homes to rebalance."); + return 0; + } + + assert(weight_sum > 0); + + log_debug("Disk space usage by all home directories to rebalance: %s — available disk space: %s", + FORMAT_BYTES(usage_sum), FORMAT_BYTES(free_sum)); + + /* Bring the home directories in a well-defined order, so that we distribute space in a reproducible + * way for the same parameters. */ + typesafe_qsort(array, c, home_cmp); + + for (int i = 0; i < c; i++) { + uint64_t new_free; + double d; + + h = array[i]; + + assert(h->rebalance_free <= free_sum); + assert(h->rebalance_usage <= usage_sum); + assert(h->rebalance_weight <= weight_sum); + + d = ((double) (free_sum / 4096) * (double) h->rebalance_weight) / (double) weight_sum; /* Calculate new space for this home in units of 4K */ + + /* Convert from units of 4K back to bytes */ + if (d >= (double) (UINT64_MAX/4096)) + new_free = UINT64_MAX; + else + new_free = (uint64_t) d * 4096; + + /* Subtract the weight and assigned space from the sums now, to distribute the rounding noise + * to the remaining home dirs */ + free_sum = LESS_BY(free_sum, new_free); + weight_sum = LESS_BY(weight_sum, h->rebalance_weight); + + /* Keep track of home directory with the least amount of space left: we want to schedule the + * next rebalance more quickly if this is low */ + if (new_free < min_free) + min_free = h->rebalance_size; + + if (new_free > UINT64_MAX - h->rebalance_usage) + h->rebalance_goal = UINT64_MAX-1; /* maximum size */ + else { + h->rebalance_goal = h->rebalance_usage + new_free; + + if (h->rebalance_min != UINT64_MAX && h->rebalance_goal < h->rebalance_min) + h->rebalance_goal = h->rebalance_min; + } + + /* Skip over this home if the state doesn't match the operation */ + if ((m->rebalance_state == REBALANCE_SHRINKING && h->rebalance_goal > h->rebalance_size) || + (m->rebalance_state == REBALANCE_GROWING && h->rebalance_goal < h->rebalance_size)) + h->rebalance_pending = false; + else { + log_debug("Rebalancing home directory '%s' %s %s %s.", h->user_name, + FORMAT_BYTES(h->rebalance_size), + special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), + FORMAT_BYTES(h->rebalance_goal)); + h->rebalance_pending = true; + } + + if ((fabs((double) h->rebalance_size - (double) h->rebalance_goal) * 100 / (double) h->rebalance_size) >= 5.0) + relevant = true; + } + + /* Scale next rebalancing interval based on the least amount of space of any of the home + * directories. We pick a time in the range 1min … 15min, scaled by log2(min_free), so that: + * 10M → ~0.7min, 100M → ~2.7min, 1G → ~4.6min, 10G → ~6.5min, 100G ~8.4 */ + m->rebalance_interval_usec = (usec_t) CLAMP((LESS_BY(log2(min_free), 22)*15*USEC_PER_MINUTE)/26, + 1 * USEC_PER_MINUTE, + 15 * USEC_PER_MINUTE); + + + log_debug("Rebalancing interval set to %s.", FORMAT_TIMESPAN(m->rebalance_interval_usec, USEC_PER_MSEC)); + + /* Let's suppress small resizes, growing/shrinking file systems isn't free after all */ + if (!relevant) { + log_debug("Skipping rebalancing, since all calculated size changes are below ±5%%."); + return 0; + } + + return c; +} + +static int manager_rebalance_apply(Manager *m) { + int c = 0, r; + Home *h; + + assert(m); + + HASHMAP_FOREACH(h, m->homes_by_name) { + _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; + + if (!h->rebalance_pending) + continue; + + h->rebalance_pending = false; + + r = home_resize(h, h->rebalance_goal, /* secret= */ NULL, /* automatic= */ true, &error); + if (r < 0) + log_warning_errno(r, "Failed to resize home '%s' for rebalancing, ignoring: %s", + h->user_name, bus_error_message(&error, r)); + else + c++; + } + + return c; +} + +static void manager_rebalance_reply_messages(Manager *m) { + int r; + + assert(m); + + for (;;) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *msg = + set_steal_first(m->rebalance_pending_method_calls); + + if (!msg) + break; + + r = sd_bus_reply_method_return(msg, NULL); + if (r < 0) + log_debug_errno(r, "Failed to reply to rebalance method call, ignoring: %m"); + } +} + +static int manager_rebalance_now(Manager *m) { + RebalanceState busy_state; /* the state to revert to when operation fails if busy */ + int r; + + assert(m); + + log_debug("Rebalancing now..."); + + /* We maintain a simple state engine here to keep track of what we are doing. We'll first shrink all + * homes that shall be shrunk and then grow all homes that shall be grown, so that they can take up + * the space now freed. */ + + for (;;) { + switch (m->rebalance_state) { + + case REBALANCE_IDLE: + case REBALANCE_PENDING: + case REBALANCE_WAITING: + /* First shrink large home dirs */ + m->rebalance_state = REBALANCE_SHRINKING; + busy_state = REBALANCE_PENDING; + + /* We are initiating the next rebalancing cycle now, let's make the queued methods + * calls the pending ones, and flush out any pending ones (which shouldn't exist at + * this time anyway) */ + set_clear(m->rebalance_pending_method_calls); + SWAP_TWO(m->rebalance_pending_method_calls, m->rebalance_queued_method_calls); + + log_debug("Shrinking phase.."); + break; + + case REBALANCE_SHRINKING: + /* Then grow small home dirs */ + m->rebalance_state = REBALANCE_GROWING; + busy_state = REBALANCE_SHRINKING; + log_debug("Growing phase.."); + break; + + case REBALANCE_GROWING: + /* Finally, we are done */ + log_info("Rebalancing complete."); + m->rebalance_state = REBALANCE_IDLE; + r = 0; + goto finish; + + case REBALANCE_OFF: + default: + assert_not_reached(); + } + + r = manager_rebalance_calculate(m); + if (r == -EBUSY) { + /* Calculations failed because one home directory is currently busy. Revert to a state that + * tells us what to do next. */ + log_debug("Can't enter phase, busy."); + m->rebalance_state = busy_state; + return r; + } + if (r < 0) + goto finish; + if (r == 0) + continue; /* got to next step immediately, if there's nothing to do */ + + r = manager_rebalance_apply(m); + if (r < 0) + goto finish; + if (r > 0) + break; /* At least one resize operation is now pending, we are done for now */ + + /* If there was nothing to apply, go for next state right-away */ + } + + return 0; + +finish: + /* Reset state and schedule next rebalance */ + m->rebalance_state = REBALANCE_IDLE; + manager_rebalance_reply_messages(m); + (void) manager_schedule_rebalance(m, /* immediately= */ false); + return r; +} + +static int on_rebalance_timer(sd_event_source *s, usec_t t, void *userdata) { + Manager *m = ASSERT_PTR(userdata); + + assert(s); + assert(IN_SET(m->rebalance_state, REBALANCE_WAITING, REBALANCE_PENDING, REBALANCE_SHRINKING, REBALANCE_GROWING)); + + (void) manager_rebalance_now(m); + return 0; +} + +int manager_schedule_rebalance(Manager *m, bool immediately) { + int r; + + assert(m); + + /* Check if there are any records where rebalancing is requested */ + if (!manager_shall_rebalance(m)) { + log_debug("Not scheduling rebalancing, not needed."); + r = 0; /* report that we didn't schedule anything because nothing needed it */ + goto turn_off; + } + + if (immediately) { + /* If we are told to rebalance immediately, then mark a rebalance as pending (even if we area + * already running one) */ + + if (m->rebalance_event_source) { + r = sd_event_source_set_time(m->rebalance_event_source, 0); + if (r < 0) { + log_error_errno(r, "Failed to schedule immediate rebalancing: %m"); + goto turn_off; + } + + r = sd_event_source_set_enabled(m->rebalance_event_source, SD_EVENT_ONESHOT); + if (r < 0) { + log_error_errno(r, "Failed to enable rebalancing event source: %m"); + goto turn_off; + } + } else { + r = sd_event_add_time(m->event, &m->rebalance_event_source, CLOCK_MONOTONIC, 0, USEC_PER_SEC, on_rebalance_timer, m); + if (r < 0) { + log_error_errno(r, "Failed to allocate rebalance event source: %m"); + goto turn_off; + } + + r = sd_event_source_set_priority(m->rebalance_event_source, SD_EVENT_PRIORITY_IDLE + 10); + if (r < 0) { + log_error_errno(r, "Failed to set rebalance event source priority: %m"); + goto turn_off; + } + + (void) sd_event_source_set_description(m->rebalance_event_source, "rebalance"); + + } + + if (!IN_SET(m->rebalance_state, REBALANCE_PENDING, REBALANCE_SHRINKING, REBALANCE_GROWING)) + m->rebalance_state = REBALANCE_PENDING; + + log_debug("Scheduled immediate rebalancing..."); + return 1; /* report that we scheduled something */ + } + + /* If we are told to schedule a rebalancing eventually, then do so only if we are not executing + * anything yet. Also if we have something scheduled already, leave it in place */ + if (!IN_SET(m->rebalance_state, REBALANCE_OFF, REBALANCE_IDLE)) + return 1; /* report that there's already something scheduled */ + + if (m->rebalance_event_source) { + r = sd_event_source_set_time_relative(m->rebalance_event_source, m->rebalance_interval_usec); + if (r < 0) { + log_error_errno(r, "Failed to schedule immediate rebalancing: %m"); + goto turn_off; + } + + r = sd_event_source_set_enabled(m->rebalance_event_source, SD_EVENT_ONESHOT); + if (r < 0) { + log_error_errno(r, "Failed to enable rebalancing event source: %m"); + goto turn_off; + } + } else { + r = sd_event_add_time_relative(m->event, &m->rebalance_event_source, CLOCK_MONOTONIC, m->rebalance_interval_usec, USEC_PER_SEC, on_rebalance_timer, m); + if (r < 0) { + log_error_errno(r, "Failed to allocate rebalance event source: %m"); + goto turn_off; + } + + r = sd_event_source_set_priority(m->rebalance_event_source, SD_EVENT_PRIORITY_IDLE + 10); + if (r < 0) { + log_error_errno(r, "Failed to set rebalance event source priority: %m"); + goto turn_off; + } + + (void) sd_event_source_set_description(m->rebalance_event_source, "rebalance"); + } + + m->rebalance_state = REBALANCE_WAITING; /* We managed to enqueue a timer event, we now wait until it fires */ + log_debug("Scheduled rebalancing in %s...", FORMAT_TIMESPAN(m->rebalance_interval_usec, 0)); + return 1; /* report that we scheduled something */ + +turn_off: + m->rebalance_event_source = sd_event_source_disable_unref(m->rebalance_event_source); + m->rebalance_state = REBALANCE_OFF; + manager_rebalance_reply_messages(m); + return r; +} + +int manager_reschedule_rebalance(Manager *m) { + int r; + + assert(m); + + /* If a rebalance is pending reschedules it so it gets executed immediately */ + + if (!IN_SET(m->rebalance_state, REBALANCE_PENDING, REBALANCE_SHRINKING, REBALANCE_GROWING)) + return 0; + + r = manager_schedule_rebalance(m, /* immediately= */ true); + if (r < 0) + return r; + + return 1; +} |