--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <sys/auxv.h>
+
+#include "dirent-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "group-record-nss.h"
+#include "missing_syscall.h"
+#include "parse-util.h"
+#include "set.h"
+#include "socket-util.h"
+#include "strv.h"
+#include "user-record-nss.h"
+#include "user-util.h"
+#include "userdb.h"
+#include "varlink.h"
+
+DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(link_hash_ops, void, trivial_hash_func, trivial_compare_func, Varlink, varlink_unref);
+
+typedef enum LookupWhat {
+ LOOKUP_USER,
+ LOOKUP_GROUP,
+ LOOKUP_MEMBERSHIP,
+ _LOOKUP_WHAT_MAX,
+} LookupWhat;
+
+struct UserDBIterator {
+ LookupWhat what;
+ Set *links;
+ bool nss_covered:1;
+ bool nss_iterating:1;
+ bool synthesize_root:1;
+ bool synthesize_nobody:1;
+ int error;
+ int nss_lock;
+ unsigned n_found;
+ sd_event *event;
+ UserRecord *found_user; /* when .what == LOOKUP_USER */
+ GroupRecord *found_group; /* when .what == LOOKUP_GROUP */
+
+ char *found_user_name, *found_group_name; /* when .what == LOOKUP_MEMBERSHIP */
+ char **members_of_group;
+ size_t index_members_of_group;
+ char *filter_user_name;
+};
+
+UserDBIterator* userdb_iterator_free(UserDBIterator *iterator) {
+ if (!iterator)
+ return NULL;
+
+ set_free(iterator->links);
+
+ switch (iterator->what) {
+
+ case LOOKUP_USER:
+ user_record_unref(iterator->found_user);
+
+ if (iterator->nss_iterating)
+ endpwent();
+
+ break;
+
+ case LOOKUP_GROUP:
+ group_record_unref(iterator->found_group);
+
+ if (iterator->nss_iterating)
+ endgrent();
+
+ break;
+
+ case LOOKUP_MEMBERSHIP:
+ free(iterator->found_user_name);
+ free(iterator->found_group_name);
+ strv_free(iterator->members_of_group);
+ free(iterator->filter_user_name);
+
+ if (iterator->nss_iterating)
+ endgrent();
+
+ break;
+
+ default:
+ assert_not_reached("Unexpected state?");
+ }
+
+ sd_event_unref(iterator->event);
+ safe_close(iterator->nss_lock);
+
+ return mfree(iterator);
+}
+
+static UserDBIterator* userdb_iterator_new(LookupWhat what) {
+ UserDBIterator *i;
+
+ assert(what >= 0);
+ assert(what < _LOOKUP_WHAT_MAX);
+
+ i = new(UserDBIterator, 1);
+ if (!i)
+ return NULL;
+
+ *i = (UserDBIterator) {
+ .what = what,
+ .nss_lock = -1,
+ };
+
+ return i;
+}
+
+struct user_group_data {
+ JsonVariant *record;
+ bool incomplete;
+};
+
+static void user_group_data_release(struct user_group_data *d) {
+ json_variant_unref(d->record);
+}
+
+static int userdb_on_query_reply(
+ Varlink *link,
+ JsonVariant *parameters,
+ const char *error_id,
+ VarlinkReplyFlags flags,
+ void *userdata) {
+
+ UserDBIterator *iterator = userdata;
+ int r;
+
+ assert(iterator);
+
+ if (error_id) {
+ log_debug("Got lookup error: %s", error_id);
+
+ if (STR_IN_SET(error_id,
+ "io.systemd.UserDatabase.NoRecordFound",
+ "io.systemd.UserDatabase.ConflictingRecordFound"))
+ r = -ESRCH;
+ else if (streq(error_id, "io.systemd.UserDatabase.ServiceNotAvailable"))
+ r = -EHOSTDOWN;
+ else if (streq(error_id, VARLINK_ERROR_TIMEOUT))
+ r = -ETIMEDOUT;
+ else
+ r = -EIO;
+
+ goto finish;
+ }
+
+ switch (iterator->what) {
+
+ case LOOKUP_USER: {
+ _cleanup_(user_group_data_release) struct user_group_data user_data = {};
+
+ static const JsonDispatch dispatch_table[] = {
+ { "record", _JSON_VARIANT_TYPE_INVALID, json_dispatch_variant, offsetof(struct user_group_data, record), 0 },
+ { "incomplete", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(struct user_group_data, incomplete), 0 },
+ {}
+ };
+ _cleanup_(user_record_unrefp) UserRecord *hr = NULL;
+
+ assert_se(!iterator->found_user);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &user_data);
+ if (r < 0)
+ goto finish;
+
+ if (!user_data.record) {
+ r = log_debug_errno(SYNTHETIC_ERRNO(EIO), "Reply is missing record key");
+ goto finish;
+ }
+
+ hr = user_record_new();
+ if (!hr) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ r = user_record_load(hr, user_data.record, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
+ if (r < 0)
+ goto finish;
+
+ if (!hr->service) {
+ r = log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "User record does not carry service information, refusing.");
+ goto finish;
+ }
+
+ hr->incomplete = user_data.incomplete;
+
+ /* We match the root user by the name since the name is our primary key. We match the nobody
+ * use by UID though, since the name might differ on OSes */
+ if (streq_ptr(hr->user_name, "root"))
+ iterator->synthesize_root = false;
+ if (hr->uid == UID_NOBODY)
+ iterator->synthesize_nobody = false;
+
+ iterator->found_user = TAKE_PTR(hr);
+ iterator->n_found++;
+
+ /* More stuff coming? then let's just exit cleanly here */
+ if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
+ return 0;
+
+ /* Otherwise, let's remove this link and exit cleanly then */
+ r = 0;
+ goto finish;
+ }
+
+ case LOOKUP_GROUP: {
+ _cleanup_(user_group_data_release) struct user_group_data group_data = {};
+
+ static const JsonDispatch dispatch_table[] = {
+ { "record", _JSON_VARIANT_TYPE_INVALID, json_dispatch_variant, offsetof(struct user_group_data, record), 0 },
+ { "incomplete", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(struct user_group_data, incomplete), 0 },
+ {}
+ };
+ _cleanup_(group_record_unrefp) GroupRecord *g = NULL;
+
+ assert_se(!iterator->found_group);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &group_data);
+ if (r < 0)
+ goto finish;
+
+ if (!group_data.record) {
+ r = log_debug_errno(SYNTHETIC_ERRNO(EIO), "Reply is missing record key");
+ goto finish;
+ }
+
+ g = group_record_new();
+ if (!g) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ r = group_record_load(g, group_data.record, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
+ if (r < 0)
+ goto finish;
+
+ if (!g->service) {
+ r = log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Group record does not carry service information, refusing.");
+ goto finish;
+ }
+
+ g->incomplete = group_data.incomplete;
+
+ if (streq_ptr(g->group_name, "root"))
+ iterator->synthesize_root = false;
+ if (g->gid == GID_NOBODY)
+ iterator->synthesize_nobody = false;
+
+ iterator->found_group = TAKE_PTR(g);
+ iterator->n_found++;
+
+ if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
+ return 0;
+
+ r = 0;
+ goto finish;
+ }
+
+ case LOOKUP_MEMBERSHIP: {
+ struct membership_data {
+ const char *user_name;
+ const char *group_name;
+ } membership_data = {};
+
+ static const JsonDispatch dispatch_table[] = {
+ { "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(struct membership_data, user_name), JSON_SAFE },
+ { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(struct membership_data, group_name), JSON_SAFE },
+ {}
+ };
+
+ assert(!iterator->found_user_name);
+ assert(!iterator->found_group_name);
+
+ r = json_dispatch(parameters, dispatch_table, NULL, 0, &membership_data);
+ if (r < 0)
+ goto finish;
+
+ iterator->found_user_name = mfree(iterator->found_user_name);
+ iterator->found_group_name = mfree(iterator->found_group_name);
+
+ iterator->found_user_name = strdup(membership_data.user_name);
+ if (!iterator->found_user_name) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ iterator->found_group_name = strdup(membership_data.group_name);
+ if (!iterator->found_group_name) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ iterator->n_found++;
+
+ if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
+ return 0;
+
+ r = 0;
+ goto finish;
+ }
+
+ default:
+ assert_not_reached("unexpected lookup");
+ }
+
+finish:
+ /* If we got one ESRCH, let that win. This way when we do a wild dump we won't be tripped up by bad
+ * errors if at least one connection ended cleanly */
+ if (r == -ESRCH || iterator->error == 0)
+ iterator->error = -r;
+
+ assert_se(set_remove(iterator->links, link) == link);
+ link = varlink_unref(link);
+ return 0;
+}
+
+static int userdb_connect(
+ UserDBIterator *iterator,
+ const char *path,
+ const char *method,
+ bool more,
+ JsonVariant *query) {
+
+ _cleanup_(varlink_unrefp) Varlink *vl = NULL;
+ int r;
+
+ assert(iterator);
+ assert(path);
+ assert(method);
+
+ r = varlink_connect_address(&vl, path);
+ if (r < 0)
+ return log_debug_errno(r, "Unable to connect to %s: %m", path);
+
+ varlink_set_userdata(vl, iterator);
+
+ if (!iterator->event) {
+ r = sd_event_new(&iterator->event);
+ if (r < 0)
+ return log_debug_errno(r, "Unable to allocate event loop: %m");
+ }
+
+ r = varlink_attach_event(vl, iterator->event, SD_EVENT_PRIORITY_NORMAL);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to attach varlink connection to event loop: %m");
+
+ (void) varlink_set_description(vl, path);
+
+ r = varlink_bind_reply(vl, userdb_on_query_reply);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to bind reply callback: %m");
+
+ if (more)
+ r = varlink_observe(vl, method, query);
+ else
+ r = varlink_invoke(vl, method, query);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to invoke varlink method: %m");
+
+ r = set_ensure_allocated(&iterator->links, &link_hash_ops);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to allocate set: %m");
+
+ r = set_put(iterator->links, vl);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to add varlink connection to set: %m");
+
+ TAKE_PTR(vl);
+ return r;
+}
+
+static int userdb_start_query(
+ UserDBIterator *iterator,
+ const char *method,
+ bool more,
+ JsonVariant *query,
+ UserDBFlags flags) {
+
+ _cleanup_(strv_freep) char **except = NULL, **only = NULL;
+ _cleanup_(closedirp) DIR *d = NULL;
+ struct dirent *de;
+ const char *e;
+ int r, ret = 0;
+
+ assert(iterator);
+ assert(method);
+
+ e = getenv("SYSTEMD_BYPASS_USERDB");
+ if (e) {
+ r = parse_boolean(e);
+ if (r > 0)
+ return -ENOLINK;
+ if (r < 0) {
+ except = strv_split(e, ":");
+ if (!except)
+ return -ENOMEM;
+ }
+ }
+
+ e = getenv("SYSTEMD_ONLY_USERDB");
+ if (e) {
+ only = strv_split(e, ":");
+ if (!only)
+ return -ENOMEM;
+ }
+
+ /* First, let's talk to the multiplexer, if we can */
+ if ((flags & (USERDB_AVOID_MULTIPLEXER|USERDB_AVOID_DYNAMIC_USER|USERDB_AVOID_NSS|USERDB_DONT_SYNTHESIZE)) == 0 &&
+ !strv_contains(except, "io.systemd.Multiplexer") &&
+ (!only || strv_contains(only, "io.systemd.Multiplexer"))) {
+ _cleanup_(json_variant_unrefp) JsonVariant *patched_query = json_variant_ref(query);
+
+ r = json_variant_set_field_string(&patched_query, "service", "io.systemd.Multiplexer");
+ if (r < 0)
+ return log_debug_errno(r, "Unable to set service JSON field: %m");
+
+ r = userdb_connect(iterator, "/run/systemd/userdb/io.systemd.Multiplexer", method, more, patched_query);
+ if (r >= 0) {
+ iterator->nss_covered = true; /* The multiplexer does NSS */
+ return 0;
+ }
+ }
+
+ d = opendir("/run/systemd/userdb/");
+ if (!d) {
+ if (errno == ENOENT)
+ return -ESRCH;
+
+ return -errno;
+ }
+
+ FOREACH_DIRENT(de, d, return -errno) {
+ _cleanup_(json_variant_unrefp) JsonVariant *patched_query = NULL;
+ _cleanup_free_ char *p = NULL;
+ bool is_nss;
+
+ if (streq(de->d_name, "io.systemd.Multiplexer")) /* We already tried this above, don't try this again */
+ continue;
+
+ if (FLAGS_SET(flags, USERDB_AVOID_DYNAMIC_USER) &&
+ streq(de->d_name, "io.systemd.DynamicUser"))
+ continue;
+
+ /* Avoid NSS is this is requested. Note that we also skip NSS when we were asked to skip the
+ * multiplexer, since in that case it's safer to do NSS in the client side emulation below
+ * (and when we run as part of systemd-userdbd.service we don't want to talk to ourselves
+ * anyway). */
+ is_nss = streq(de->d_name, "io.systemd.NameServiceSwitch");
+ if ((flags & (USERDB_AVOID_NSS|USERDB_AVOID_MULTIPLEXER)) && is_nss)
+ continue;
+
+ if (strv_contains(except, de->d_name))
+ continue;
+
+ if (only && !strv_contains(only, de->d_name))
+ continue;
+
+ p = path_join("/run/systemd/userdb/", de->d_name);
+ if (!p)
+ return -ENOMEM;
+
+ patched_query = json_variant_ref(query);
+ r = json_variant_set_field_string(&patched_query, "service", de->d_name);
+ if (r < 0)
+ return log_debug_errno(r, "Unable to set service JSON field: %m");
+
+ r = userdb_connect(iterator, p, method, more, patched_query);
+ if (is_nss && r >= 0) /* Turn off fallback NSS if we found the NSS service and could connect
+ * to it */
+ iterator->nss_covered = true;
+
+ if (ret == 0 && r < 0)
+ ret = r;
+ }
+
+ if (set_isempty(iterator->links))
+ return ret; /* propagate last error we saw if we couldn't connect to anything. */
+
+ /* We connected to some services, in this case, ignore the ones we failed on */
+ return 0;
+}
+
+static int userdb_process(
+ UserDBIterator *iterator,
+ UserRecord **ret_user_record,
+ GroupRecord **ret_group_record,
+ char **ret_user_name,
+ char **ret_group_name) {
+
+ int r;
+
+ assert(iterator);
+
+ for (;;) {
+ if (iterator->what == LOOKUP_USER && iterator->found_user) {
+ if (ret_user_record)
+ *ret_user_record = TAKE_PTR(iterator->found_user);
+ else
+ iterator->found_user = user_record_unref(iterator->found_user);
+
+ if (ret_group_record)
+ *ret_group_record = NULL;
+ if (ret_user_name)
+ *ret_user_name = NULL;
+ if (ret_group_name)
+ *ret_group_name = NULL;
+
+ return 0;
+ }
+
+ if (iterator->what == LOOKUP_GROUP && iterator->found_group) {
+ if (ret_group_record)
+ *ret_group_record = TAKE_PTR(iterator->found_group);
+ else
+ iterator->found_group = group_record_unref(iterator->found_group);
+
+ if (ret_user_record)
+ *ret_user_record = NULL;
+ if (ret_user_name)
+ *ret_user_name = NULL;
+ if (ret_group_name)
+ *ret_group_name = NULL;
+
+ return 0;
+ }
+
+ if (iterator->what == LOOKUP_MEMBERSHIP && iterator->found_user_name && iterator->found_group_name) {
+ if (ret_user_name)
+ *ret_user_name = TAKE_PTR(iterator->found_user_name);
+ else
+ iterator->found_user_name = mfree(iterator->found_user_name);
+
+ if (ret_group_name)
+ *ret_group_name = TAKE_PTR(iterator->found_group_name);
+ else
+ iterator->found_group_name = mfree(iterator->found_group_name);
+
+ if (ret_user_record)
+ *ret_user_record = NULL;
+ if (ret_group_record)
+ *ret_group_record = NULL;
+
+ return 0;
+ }
+
+ if (set_isempty(iterator->links)) {
+ if (iterator->error == 0)
+ return -ESRCH;
+
+ return -abs(iterator->error);
+ }
+
+ if (!iterator->event)
+ return -ESRCH;
+
+ r = sd_event_run(iterator->event, UINT64_MAX);
+ if (r < 0)
+ return r;
+ }
+}
+
+static int synthetic_root_user_build(UserRecord **ret) {
+ return user_record_build(
+ ret,
+ JSON_BUILD_OBJECT(JSON_BUILD_PAIR("userName", JSON_BUILD_STRING("root")),
+ JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(0)),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(0)),
+ JSON_BUILD_PAIR("homeDirectory", JSON_BUILD_STRING("/root")),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
+}
+
+static int synthetic_nobody_user_build(UserRecord **ret) {
+ return user_record_build(
+ ret,
+ JSON_BUILD_OBJECT(JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(NOBODY_USER_NAME)),
+ JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(UID_NOBODY)),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(GID_NOBODY)),
+ JSON_BUILD_PAIR("shell", JSON_BUILD_STRING(NOLOGIN)),
+ JSON_BUILD_PAIR("locked", JSON_BUILD_BOOLEAN(true)),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
+}
+
+int userdb_by_name(const char *name, UserDBFlags flags, UserRecord **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ int r;
+
+ if (!valid_user_group_name(name))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(name))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_USER);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", false, query, flags);
+ if (r >= 0) {
+ r = userdb_process(iterator, ret, NULL, NULL, NULL);
+ if (r >= 0)
+ return r;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
+ /* Make sure the NSS lookup doesn't recurse back to us. (EBUSY is fine here, it just means we
+ * already took the lock from our thread, which is totally OK.) */
+ r = userdb_nss_compat_disable();
+ if (r >= 0 || r == -EBUSY) {
+ iterator->nss_lock = r;
+
+ /* Client-side NSS fallback */
+ r = nss_user_record_by_name(name, ret);
+ if (r >= 0)
+ return r;
+ }
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
+ if (streq(name, "root"))
+ return synthetic_root_user_build(ret);
+
+ if (streq(name, NOBODY_USER_NAME) && synthesize_nobody())
+ return synthetic_nobody_user_build(ret);
+ }
+
+ return r;
+}
+
+int userdb_by_uid(uid_t uid, UserDBFlags flags, UserRecord **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ int r;
+
+ if (!uid_is_valid(uid))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(uid))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_USER);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", false, query, flags);
+ if (r >= 0) {
+ r = userdb_process(iterator, ret, NULL, NULL, NULL);
+ if (r >= 0)
+ return r;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
+ r = userdb_nss_compat_disable();
+ if (r >= 0 || r == -EBUSY) {
+ iterator->nss_lock = r;
+
+ /* Client-side NSS fallback */
+ r = nss_user_record_by_uid(uid, ret);
+ if (r >= 0)
+ return r;
+ }
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
+ if (uid == 0)
+ return synthetic_root_user_build(ret);
+
+ if (uid == UID_NOBODY && synthesize_nobody())
+ return synthetic_nobody_user_build(ret);
+ }
+
+ return r;
+}
+
+int userdb_all(UserDBFlags flags, UserDBIterator **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ int r;
+
+ assert(ret);
+
+ iterator = userdb_iterator_new(LOOKUP_USER);
+ if (!iterator)
+ return -ENOMEM;
+
+ iterator->synthesize_root = iterator->synthesize_nobody = !FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE);
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", true, NULL, flags);
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && (r < 0 || !iterator->nss_covered)) {
+ iterator->nss_lock = userdb_nss_compat_disable();
+ if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
+ return iterator->nss_lock;
+
+ setpwent();
+ iterator->nss_iterating = true;
+ goto finish;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE))
+ goto finish;
+
+ return r;
+
+finish:
+ *ret = TAKE_PTR(iterator);
+ return 0;
+}
+
+int userdb_iterator_get(UserDBIterator *iterator, UserRecord **ret) {
+ int r;
+
+ assert(iterator);
+ assert(iterator->what == LOOKUP_USER);
+
+ if (iterator->nss_iterating) {
+ struct passwd *pw;
+
+ /* If NSS isn't covered elsewhere, let's iterate through it first, since it probably contains
+ * the more traditional sources, which are probably good to show first. */
+
+ pw = getpwent();
+ if (pw) {
+ _cleanup_free_ char *buffer = NULL;
+ bool incomplete = false;
+ struct spwd spwd;
+
+ if (streq_ptr(pw->pw_name, "root"))
+ iterator->synthesize_root = false;
+ if (pw->pw_uid == UID_NOBODY)
+ iterator->synthesize_nobody = false;
+
+ r = nss_spwd_for_passwd(pw, &spwd, &buffer);
+ if (r < 0) {
+ log_debug_errno(r, "Failed to acquire shadow entry for user %s, ignoring: %m", pw->pw_name);
+ incomplete = ERRNO_IS_PRIVILEGE(r);
+ }
+
+ r = nss_passwd_to_user_record(pw, r >= 0 ? &spwd : NULL, ret);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ (*ret)->incomplete = incomplete;
+ return r;
+ }
+
+ if (errno != 0)
+ log_debug_errno(errno, "Failure to iterate NSS user database, ignoring: %m");
+
+ iterator->nss_iterating = false;
+ endpwent();
+ }
+
+ r = userdb_process(iterator, ret, NULL, NULL, NULL);
+
+ if (r < 0) {
+ if (iterator->synthesize_root) {
+ iterator->synthesize_root = false;
+ iterator->n_found++;
+ return synthetic_root_user_build(ret);
+ }
+
+ if (iterator->synthesize_nobody) {
+ iterator->synthesize_nobody = false;
+ iterator->n_found++;
+ return synthetic_nobody_user_build(ret);
+ }
+ }
+
+ /* if we found at least one entry, then ignore errors and indicate that we reached the end */
+ if (r < 0 && iterator->n_found > 0)
+ return -ESRCH;
+
+ return r;
+}
+
+static int synthetic_root_group_build(GroupRecord **ret) {
+ return group_record_build(
+ ret,
+ JSON_BUILD_OBJECT(JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING("root")),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(0)),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
+}
+
+static int synthetic_nobody_group_build(GroupRecord **ret) {
+ return group_record_build(
+ ret,
+ JSON_BUILD_OBJECT(JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(NOBODY_GROUP_NAME)),
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(GID_NOBODY)),
+ JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
+}
+
+int groupdb_by_name(const char *name, UserDBFlags flags, GroupRecord **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ int r;
+
+ if (!valid_user_group_name(name))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(name))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_GROUP);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", false, query, flags);
+ if (r >= 0) {
+ r = userdb_process(iterator, NULL, ret, NULL, NULL);
+ if (r >= 0)
+ return r;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
+ r = userdb_nss_compat_disable();
+ if (r >= 0 || r == -EBUSY) {
+ iterator->nss_lock = r;
+
+ r = nss_group_record_by_name(name, ret);
+ if (r >= 0)
+ return r;
+ }
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
+ if (streq(name, "root"))
+ return synthetic_root_group_build(ret);
+
+ if (streq(name, NOBODY_GROUP_NAME) && synthesize_nobody())
+ return synthetic_nobody_group_build(ret);
+ }
+
+ return r;
+}
+
+int groupdb_by_gid(gid_t gid, UserDBFlags flags, GroupRecord **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ int r;
+
+ if (!gid_is_valid(gid))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(gid))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_GROUP);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", false, query, flags);
+ if (r >= 0) {
+ r = userdb_process(iterator, NULL, ret, NULL, NULL);
+ if (r >= 0)
+ return r;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
+ r = userdb_nss_compat_disable();
+ if (r >= 0 || r == -EBUSY) {
+ iterator->nss_lock = r;
+
+ r = nss_group_record_by_gid(gid, ret);
+ if (r >= 0)
+ return r;
+ }
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
+ if (gid == 0)
+ return synthetic_root_group_build(ret);
+
+ if (gid == GID_NOBODY && synthesize_nobody())
+ return synthetic_nobody_group_build(ret);
+ }
+
+ return r;
+}
+
+int groupdb_all(UserDBFlags flags, UserDBIterator **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ int r;
+
+ assert(ret);
+
+ iterator = userdb_iterator_new(LOOKUP_GROUP);
+ if (!iterator)
+ return -ENOMEM;
+
+ iterator->synthesize_root = iterator->synthesize_nobody = !FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE);
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", true, NULL, flags);
+
+ if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && (r < 0 || !iterator->nss_covered)) {
+ iterator->nss_lock = userdb_nss_compat_disable();
+ if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
+ return iterator->nss_lock;
+
+ setgrent();
+ iterator->nss_iterating = true;
+ goto finish;
+ }
+
+ if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE))
+ goto finish;
+
+ return r;
+
+finish:
+ *ret = TAKE_PTR(iterator);
+ return 0;
+}
+
+int groupdb_iterator_get(UserDBIterator *iterator, GroupRecord **ret) {
+ int r;
+
+ assert(iterator);
+ assert(iterator->what == LOOKUP_GROUP);
+
+ if (iterator->nss_iterating) {
+ struct group *gr;
+
+ errno = 0;
+ gr = getgrent();
+ if (gr) {
+ _cleanup_free_ char *buffer = NULL;
+ bool incomplete = false;
+ struct sgrp sgrp;
+
+ if (streq_ptr(gr->gr_name, "root"))
+ iterator->synthesize_root = false;
+ if (gr->gr_gid == GID_NOBODY)
+ iterator->synthesize_nobody = false;
+
+ r = nss_sgrp_for_group(gr, &sgrp, &buffer);
+ if (r < 0) {
+ log_debug_errno(r, "Failed to acquire shadow entry for group %s, ignoring: %m", gr->gr_name);
+ incomplete = ERRNO_IS_PRIVILEGE(r);
+ }
+
+ r = nss_group_to_group_record(gr, r >= 0 ? &sgrp : NULL, ret);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ (*ret)->incomplete = incomplete;
+ return r;
+ }
+
+ if (errno != 0)
+ log_debug_errno(errno, "Failure to iterate NSS group database, ignoring: %m");
+
+ iterator->nss_iterating = false;
+ endgrent();
+ }
+
+ r = userdb_process(iterator, NULL, ret, NULL, NULL);
+ if (r < 0) {
+ if (iterator->synthesize_root) {
+ iterator->synthesize_root = false;
+ iterator->n_found++;
+ return synthetic_root_group_build(ret);
+ }
+
+ if (iterator->synthesize_nobody) {
+ iterator->synthesize_nobody = false;
+ iterator->n_found++;
+ return synthetic_nobody_group_build(ret);
+ }
+ }
+
+ /* if we found at least one entry, then ignore errors and indicate that we reached the end */
+ if (r < 0 && iterator->n_found > 0)
+ return -ESRCH;
+
+ return r;
+}
+
+int membershipdb_by_user(const char *name, UserDBFlags flags, UserDBIterator **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ int r;
+
+ assert(ret);
+
+ if (!valid_user_group_name(name))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(name))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, query, flags);
+ if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
+ goto finish;
+
+ iterator->nss_lock = userdb_nss_compat_disable();
+ if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
+ return iterator->nss_lock;
+
+ iterator->filter_user_name = strdup(name);
+ if (!iterator->filter_user_name)
+ return -ENOMEM;
+
+ setgrent();
+ iterator->nss_iterating = true;
+
+ r = 0;
+
+finish:
+ if (r >= 0)
+ *ret = TAKE_PTR(iterator);
+ return r;
+}
+
+int membershipdb_by_group(const char *name, UserDBFlags flags, UserDBIterator **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
+ _cleanup_(group_record_unrefp) GroupRecord *gr = NULL;
+ int r;
+
+ assert(ret);
+
+ if (!valid_user_group_name(name))
+ return -EINVAL;
+
+ r = json_build(&query, JSON_BUILD_OBJECT(
+ JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(name))));
+ if (r < 0)
+ return r;
+
+ iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, query, flags);
+ if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
+ goto finish;
+
+ iterator->nss_lock = userdb_nss_compat_disable();
+ if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
+ return iterator->nss_lock;
+
+ /* We ignore all errors here, since the group might be defined by a userdb native service, and we queried them already above. */
+ (void) nss_group_record_by_name(name, &gr);
+ if (gr) {
+ iterator->members_of_group = strv_copy(gr->members);
+ if (!iterator->members_of_group)
+ return -ENOMEM;
+
+ iterator->index_members_of_group = 0;
+
+ iterator->found_group_name = strdup(name);
+ if (!iterator->found_group_name)
+ return -ENOMEM;
+ }
+
+ r = 0;
+
+finish:
+ if (r >= 0)
+ *ret = TAKE_PTR(iterator);
+
+ return r;
+}
+
+int membershipdb_all(UserDBFlags flags, UserDBIterator **ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ int r;
+
+ assert(ret);
+
+ iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
+ if (!iterator)
+ return -ENOMEM;
+
+ r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, NULL, flags);
+ if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
+ goto finish;
+
+ iterator->nss_lock = userdb_nss_compat_disable();
+ if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
+ return iterator->nss_lock;
+
+ setgrent();
+ iterator->nss_iterating = true;
+
+ r = 0;
+
+finish:
+ if (r >= 0)
+ *ret = TAKE_PTR(iterator);
+
+ return r;
+}
+
+int membershipdb_iterator_get(
+ UserDBIterator *iterator,
+ char **ret_user,
+ char **ret_group) {
+
+ int r;
+
+ assert(iterator);
+
+ for (;;) {
+ /* If we are iteratring through NSS acquire a new group entry if we haven't acquired one yet. */
+ if (!iterator->members_of_group) {
+ struct group *g;
+
+ if (!iterator->nss_iterating)
+ break;
+
+ assert(!iterator->found_user_name);
+ do {
+ errno = 0;
+ g = getgrent();
+ if (!g) {
+ if (errno != 0)
+ log_debug_errno(errno, "Failure during NSS group iteration, ignoring: %m");
+ break;
+ }
+
+ } while (iterator->filter_user_name ? !strv_contains(g->gr_mem, iterator->filter_user_name) :
+ strv_isempty(g->gr_mem));
+
+ if (g) {
+ r = free_and_strdup(&iterator->found_group_name, g->gr_name);
+ if (r < 0)
+ return r;
+
+ if (iterator->filter_user_name)
+ iterator->members_of_group = strv_new(iterator->filter_user_name);
+ else
+ iterator->members_of_group = strv_copy(g->gr_mem);
+ if (!iterator->members_of_group)
+ return -ENOMEM;
+
+ iterator->index_members_of_group = 0;
+ } else {
+ iterator->nss_iterating = false;
+ endgrent();
+ break;
+ }
+ }
+
+ assert(iterator->found_group_name);
+ assert(iterator->members_of_group);
+ assert(!iterator->found_user_name);
+
+ if (iterator->members_of_group[iterator->index_members_of_group]) {
+ _cleanup_free_ char *cu = NULL, *cg = NULL;
+
+ if (ret_user) {
+ cu = strdup(iterator->members_of_group[iterator->index_members_of_group]);
+ if (!cu)
+ return -ENOMEM;
+ }
+
+ if (ret_group) {
+ cg = strdup(iterator->found_group_name);
+ if (!cg)
+ return -ENOMEM;
+ }
+
+ if (ret_user)
+ *ret_user = TAKE_PTR(cu);
+
+ if (ret_group)
+ *ret_group = TAKE_PTR(cg);
+
+ iterator->index_members_of_group++;
+ return 0;
+ }
+
+ iterator->members_of_group = strv_free(iterator->members_of_group);
+ iterator->found_group_name = mfree(iterator->found_group_name);
+ }
+
+ r = userdb_process(iterator, NULL, NULL, ret_user, ret_group);
+ if (r < 0 && iterator->n_found > 0)
+ return -ESRCH;
+
+ return r;
+}
+
+int membershipdb_by_group_strv(const char *name, UserDBFlags flags, char ***ret) {
+ _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+ _cleanup_strv_free_ char **members = NULL;
+ int r;
+
+ assert(name);
+ assert(ret);
+
+ r = membershipdb_by_group(name, flags, &iterator);
+ if (r < 0)
+ return r;
+
+ for (;;) {
+ _cleanup_free_ char *user_name = NULL;
+
+ r = membershipdb_iterator_get(iterator, &user_name, NULL);
+ if (r == -ESRCH)
+ break;
+ if (r < 0)
+ return r;
+
+ r = strv_consume(&members, TAKE_PTR(user_name));
+ if (r < 0)
+ return r;
+ }
+
+ strv_sort(members);
+ strv_uniq(members);
+
+ *ret = TAKE_PTR(members);
+ return 0;
+}
+
+static int userdb_thread_sockaddr(struct sockaddr_un *ret_sa, socklen_t *ret_salen) {
+ static const uint8_t
+ k1[16] = { 0x35, 0xc1, 0x1f, 0x41, 0x59, 0xc6, 0xa0, 0xf9, 0x33, 0x4b, 0x17, 0x3d, 0xb9, 0xf6, 0x14, 0xd9 },
+ k2[16] = { 0x6a, 0x11, 0x4c, 0x37, 0xe5, 0xa3, 0x8c, 0xa6, 0x93, 0x55, 0x64, 0x8c, 0x93, 0xee, 0xa1, 0x7b };
+
+ struct siphash sh;
+ uint64_t x, y;
+ pid_t tid;
+ void *p;
+
+ assert(ret_sa);
+ assert(ret_salen);
+
+ /* This calculates an AF_UNIX socket address in the abstract namespace whose existance works as an
+ * indicator whether to emulate NSS records for complex user records that are also available via the
+ * varlink protocol. The name of the socket is picked in a way so that:
+ *
+ * → it is per-thread (by hashing from the TID)
+ *
+ * → is not guessable for foreign processes (by hashing from the — hopefully secret — AT_RANDOM
+ * value every process gets passed from the kernel
+ *
+ * By using a socket the NSS emulation can be nicely turned off for limited amounts of time only,
+ * simply controlled by the lifetime of the fd itself. By using an AF_UNIX socket in the abstract
+ * namespace the lock is automatically cleaned up when the process dies abnormally.
+ *
+ */
+
+ p = ULONG_TO_PTR(getauxval(AT_RANDOM));
+ if (!p)
+ return -EIO;
+
+ tid = gettid();
+
+ siphash24_init(&sh, k1);
+ siphash24_compress(p, 16, &sh);
+ siphash24_compress(&tid, sizeof(tid), &sh);
+ x = siphash24_finalize(&sh);
+
+ siphash24_init(&sh, k2);
+ siphash24_compress(p, 16, &sh);
+ siphash24_compress(&tid, sizeof(tid), &sh);
+ y = siphash24_finalize(&sh);
+
+ *ret_sa = (struct sockaddr_un) {
+ .sun_family = AF_UNIX,
+ };
+
+ sprintf(ret_sa->sun_path + 1, "userdb-%016" PRIx64 "%016" PRIx64, x, y);
+ *ret_salen = offsetof(struct sockaddr_un, sun_path) + 1 + 7 + 32;
+
+ return 0;
+}
+
+int userdb_nss_compat_is_enabled(void) {
+ _cleanup_close_ int fd = -1;
+ union sockaddr_union sa;
+ socklen_t salen;
+ int r;
+
+ /* Tests whether the NSS compatibility logic is currently turned on for the invoking thread. Returns
+ * true if NSS compatibility is turned on, i.e. whether NSS records shall be synthesized from complex
+ * user records. */
+
+ r = userdb_thread_sockaddr(&sa.un, &salen);
+ if (r < 0)
+ return r;
+
+ fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ return -errno;
+
+ /* Try to connect(). This doesn't do anything really, except that it checks whether the socket
+ * address is bound at all. */
+ if (connect(fd, &sa.sa, salen) < 0) {
+ if (errno == ECONNREFUSED) /* the socket is not bound, hence NSS emulation shall be done */
+ return true;
+
+ return -errno;
+ }
+
+ return false;
+}
+
+int userdb_nss_compat_disable(void) {
+ _cleanup_close_ int fd = -1;
+ union sockaddr_union sa;
+ socklen_t salen;
+ int r;
+
+ /* Turn off the NSS compatibility logic for the invoking thread. By default NSS records are
+ * synthesized for all complex user records looked up via NSS. If this call is invoked this is
+ * disabled for the invoking thread, but only for it. A caller that natively supports the varlink
+ * user record protocol may use that to turn off the compatibility for NSS lookups. */
+
+ r = userdb_thread_sockaddr(&sa.un, &salen);
+ if (r < 0)
+ return r;
+
+ fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ if (fd < 0)
+ return -errno;
+
+ if (bind(fd, &sa.sa, salen) < 0) {
+ if (errno == EADDRINUSE) /* lock already taken, convert this into a recognizable error */
+ return -EBUSY;
+
+ return -errno;
+ }
+
+ return TAKE_FD(fd);
+}
projects / thirdparty / systemd.git / commitdiff
