From b750101eb236130cf056c675997decbac904cc49 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:35:18 +0200 Subject: Adding upstream version 252.22. Signed-off-by: Daniel Baumann --- src/userdb/userwork.c | 570 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 570 insertions(+) create mode 100644 src/userdb/userwork.c (limited to 'src/userdb/userwork.c') diff --git a/src/userdb/userwork.c b/src/userdb/userwork.c new file mode 100644 index 0000000..21a869d --- /dev/null +++ b/src/userdb/userwork.c @@ -0,0 +1,570 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include +#include + +#include "sd-daemon.h" + +#include "env-util.h" +#include "fd-util.h" +#include "group-record.h" +#include "io-util.h" +#include "main-func.h" +#include "process-util.h" +#include "strv.h" +#include "time-util.h" +#include "user-record-nss.h" +#include "user-record.h" +#include "user-util.h" +#include "userdb.h" +#include "varlink.h" + +#define ITERATIONS_MAX 64U +#define RUNTIME_MAX_USEC (5 * USEC_PER_MINUTE) +#define PRESSURE_SLEEP_TIME_USEC (50 * USEC_PER_MSEC) +#define CONNECTION_IDLE_USEC (15 * USEC_PER_SEC) +#define LISTEN_IDLE_USEC (90 * USEC_PER_SEC) + +typedef struct LookupParameters { + const char *user_name; + const char *group_name; + union { + uid_t uid; + gid_t gid; + }; + const char *service; +} LookupParameters; + +static int add_nss_service(JsonVariant **v) { + _cleanup_(json_variant_unrefp) JsonVariant *status = NULL, *z = NULL; + sd_id128_t mid; + int r; + + assert(v); + + /* Patch in service field if it's missing. The assumption here is that this field is unset only for + * NSS records */ + + if (json_variant_by_key(*v, "service")) + return 0; + + r = sd_id128_get_machine(&mid); + if (r < 0) + return r; + + status = json_variant_ref(json_variant_by_key(*v, "status")); + z = json_variant_ref(json_variant_by_key(status, SD_ID128_TO_STRING(mid))); + + if (json_variant_by_key(z, "service")) + return 0; + + r = json_variant_set_field_string(&z, "service", "io.systemd.NameServiceSwitch"); + if (r < 0) + return r; + + r = json_variant_set_field(&status, SD_ID128_TO_STRING(mid), z); + if (r < 0) + return r; + + return json_variant_set_field(v, "status", status); +} + +static int build_user_json(Varlink *link, UserRecord *ur, JsonVariant **ret) { + _cleanup_(user_record_unrefp) UserRecord *stripped = NULL; + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + UserRecordLoadFlags flags; + uid_t peer_uid; + bool trusted; + int r; + + assert(ur); + assert(ret); + + r = varlink_get_peer_uid(link, &peer_uid); + if (r < 0) { + log_debug_errno(r, "Unable to query peer UID, ignoring: %m"); + trusted = false; + } else + trusted = peer_uid == 0 || peer_uid == ur->uid; + + flags = USER_RECORD_REQUIRE_REGULAR|USER_RECORD_ALLOW_PER_MACHINE|USER_RECORD_ALLOW_BINDING|USER_RECORD_STRIP_SECRET|USER_RECORD_ALLOW_STATUS|USER_RECORD_ALLOW_SIGNATURE|USER_RECORD_PERMISSIVE; + if (trusted) + flags |= USER_RECORD_ALLOW_PRIVILEGED; + else + flags |= USER_RECORD_STRIP_PRIVILEGED; + + r = user_record_clone(ur, flags, &stripped); + if (r < 0) + return r; + + stripped->incomplete = + ur->incomplete || + (FLAGS_SET(ur->mask, USER_RECORD_PRIVILEGED) && + !FLAGS_SET(stripped->mask, USER_RECORD_PRIVILEGED)); + + v = json_variant_ref(stripped->json); + r = add_nss_service(&v); + if (r < 0) + return r; + + return json_build(ret, JSON_BUILD_OBJECT( + JSON_BUILD_PAIR("record", JSON_BUILD_VARIANT(v)), + JSON_BUILD_PAIR("incomplete", JSON_BUILD_BOOLEAN(stripped->incomplete)))); +} + +static int userdb_flags_from_service(Varlink *link, const char *service, UserDBFlags *ret) { + assert(link); + assert(ret); + + if (streq_ptr(service, "io.systemd.NameServiceSwitch")) + *ret = USERDB_NSS_ONLY|USERDB_AVOID_MULTIPLEXER; + else if (streq_ptr(service, "io.systemd.DropIn")) + *ret = USERDB_DROPIN_ONLY|USERDB_AVOID_MULTIPLEXER; + else if (streq_ptr(service, "io.systemd.Multiplexer")) + *ret = USERDB_AVOID_MULTIPLEXER; + else + return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL); + + return 0; +} + +static int vl_method_get_user_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { + + static const JsonDispatch dispatch_table[] = { + { "uid", JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid, offsetof(LookupParameters, uid), 0 }, + { "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 }, + { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 }, + {} + }; + + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + _cleanup_(user_record_unrefp) UserRecord *hr = NULL; + LookupParameters p = { + .uid = UID_INVALID, + }; + UserDBFlags userdb_flags; + int r; + + assert(parameters); + + r = json_dispatch(parameters, dispatch_table, NULL, 0, &p); + if (r < 0) + return r; + + r = userdb_flags_from_service(link, p.service, &userdb_flags); + if (r != 0) /* return value of < 0 means error (as usual); > 0 means 'already processed and replied, + * we are done'; == 0 means 'not processed, caller should process now' */ + return r; + + if (uid_is_valid(p.uid)) + r = userdb_by_uid(p.uid, userdb_flags, &hr); + else if (p.user_name) + r = userdb_by_name(p.user_name, userdb_flags, &hr); + else { + _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL; + _cleanup_(json_variant_unrefp) JsonVariant *last = NULL; + + r = userdb_all(userdb_flags, &iterator); + if (IN_SET(r, -ESRCH, -ENOLINK)) + /* We turn off Varlink lookups in various cases (e.g. in case we only enable DropIn + * backend) — this might make userdb_all return ENOLINK (which indicates that varlink + * was off and no other suitable source or entries were found). Let's hide this + * implementation detail and always return NoRecordFound in this case, since from a + * client's perspective it's irrelevant if there was no entry at all or just not on + * the service that the query was limited to. */ + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + if (r < 0) + return r; + + for (;;) { + _cleanup_(user_record_unrefp) UserRecord *z = NULL; + + r = userdb_iterator_get(iterator, &z); + if (r == -ESRCH) + break; + if (r < 0) + return r; + + if (last) { + r = varlink_notify(link, last); + if (r < 0) + return r; + + last = json_variant_unref(last); + } + + r = build_user_json(link, z, &last); + if (r < 0) + return r; + } + + if (!last) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + + return varlink_reply(link, last); + } + if (r == -ESRCH) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + if (r < 0) { + log_debug_errno(r, "User lookup failed abnormally: %m"); + return varlink_error(link, "io.systemd.UserDatabase.ServiceNotAvailable", NULL); + } + + if ((uid_is_valid(p.uid) && hr->uid != p.uid) || + (p.user_name && !streq(hr->user_name, p.user_name))) + return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL); + + r = build_user_json(link, hr, &v); + if (r < 0) + return r; + + return varlink_reply(link, v); +} + +static int build_group_json(Varlink *link, GroupRecord *gr, JsonVariant **ret) { + _cleanup_(group_record_unrefp) GroupRecord *stripped = NULL; + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + UserRecordLoadFlags flags; + uid_t peer_uid; + bool trusted; + int r; + + assert(gr); + assert(ret); + + r = varlink_get_peer_uid(link, &peer_uid); + if (r < 0) { + log_debug_errno(r, "Unable to query peer UID, ignoring: %m"); + trusted = false; + } else + trusted = peer_uid == 0; + + flags = USER_RECORD_REQUIRE_REGULAR|USER_RECORD_ALLOW_PER_MACHINE|USER_RECORD_ALLOW_BINDING|USER_RECORD_STRIP_SECRET|USER_RECORD_ALLOW_STATUS|USER_RECORD_ALLOW_SIGNATURE|USER_RECORD_PERMISSIVE; + if (trusted) + flags |= USER_RECORD_ALLOW_PRIVILEGED; + else + flags |= USER_RECORD_STRIP_PRIVILEGED; + + r = group_record_clone(gr, flags, &stripped); + if (r < 0) + return r; + + stripped->incomplete = + gr->incomplete || + (FLAGS_SET(gr->mask, USER_RECORD_PRIVILEGED) && + !FLAGS_SET(stripped->mask, USER_RECORD_PRIVILEGED)); + + v = json_variant_ref(gr->json); + r = add_nss_service(&v); + if (r < 0) + return r; + + return json_build(ret, JSON_BUILD_OBJECT( + JSON_BUILD_PAIR("record", JSON_BUILD_VARIANT(v)), + JSON_BUILD_PAIR("incomplete", JSON_BUILD_BOOLEAN(stripped->incomplete)))); +} + +static int vl_method_get_group_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { + + static const JsonDispatch dispatch_table[] = { + { "gid", JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid, offsetof(LookupParameters, gid), 0 }, + { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 }, + { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 }, + {} + }; + + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + _cleanup_(group_record_unrefp) GroupRecord *g = NULL; + LookupParameters p = { + .gid = GID_INVALID, + }; + UserDBFlags userdb_flags; + int r; + + assert(parameters); + + r = json_dispatch(parameters, dispatch_table, NULL, 0, &p); + if (r < 0) + return r; + + r = userdb_flags_from_service(link, p.service, &userdb_flags); + if (r != 0) + return r; + + if (gid_is_valid(p.gid)) + r = groupdb_by_gid(p.gid, userdb_flags, &g); + else if (p.group_name) + r = groupdb_by_name(p.group_name, userdb_flags, &g); + else { + _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL; + _cleanup_(json_variant_unrefp) JsonVariant *last = NULL; + + r = groupdb_all(userdb_flags, &iterator); + if (IN_SET(r, -ESRCH, -ENOLINK)) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + if (r < 0) + return r; + + for (;;) { + _cleanup_(group_record_unrefp) GroupRecord *z = NULL; + + r = groupdb_iterator_get(iterator, &z); + if (r == -ESRCH) + break; + if (r < 0) + return r; + + if (last) { + r = varlink_notify(link, last); + if (r < 0) + return r; + + last = json_variant_unref(last); + } + + r = build_group_json(link, z, &last); + if (r < 0) + return r; + } + + if (!last) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + + return varlink_reply(link, last); + } + if (r == -ESRCH) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + if (r < 0) { + log_debug_errno(r, "Group lookup failed abnormally: %m"); + return varlink_error(link, "io.systemd.UserDatabase.ServiceNotAvailable", NULL); + } + + if ((uid_is_valid(p.gid) && g->gid != p.gid) || + (p.group_name && !streq(g->group_name, p.group_name))) + return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL); + + r = build_group_json(link, g, &v); + if (r < 0) + return r; + + return varlink_reply(link, v); +} + +static int vl_method_get_memberships(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { + static const JsonDispatch dispatch_table[] = { + { "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 }, + { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 }, + { "service", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service), 0 }, + {} + }; + + _cleanup_free_ char *last_user_name = NULL, *last_group_name = NULL; + _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL; + LookupParameters p = {}; + UserDBFlags userdb_flags; + int r; + + assert(parameters); + + r = json_dispatch(parameters, dispatch_table, NULL, 0, &p); + if (r < 0) + return r; + + r = userdb_flags_from_service(link, p.service, &userdb_flags); + if (r != 0) + return r; + + if (p.group_name) + r = membershipdb_by_group(p.group_name, userdb_flags, &iterator); + else if (p.user_name) + r = membershipdb_by_user(p.user_name, userdb_flags, &iterator); + else + r = membershipdb_all(userdb_flags, &iterator); + if (IN_SET(r, -ESRCH, -ENOLINK)) + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + if (r < 0) + return r; + + for (;;) { + _cleanup_free_ char *user_name = NULL, *group_name = NULL; + + r = membershipdb_iterator_get(iterator, &user_name, &group_name); + if (r == -ESRCH) + break; + if (r < 0) + return r; + + /* If both group + user are specified do a-posteriori filtering */ + if (p.group_name && p.user_name && !streq(group_name, p.group_name)) + continue; + + if (last_user_name) { + assert(last_group_name); + + r = varlink_notifyb(link, JSON_BUILD_OBJECT( + JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)), + JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name)))); + if (r < 0) + return r; + } + + free_and_replace(last_user_name, user_name); + free_and_replace(last_group_name, group_name); + } + + if (!last_user_name) { + assert(!last_group_name); + return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL); + } + + assert(last_group_name); + + return varlink_replyb(link, JSON_BUILD_OBJECT( + JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)), + JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name)))); +} + +static int process_connection(VarlinkServer *server, int fd) { + _cleanup_(varlink_close_unrefp) Varlink *vl = NULL; + int r; + + r = varlink_server_add_connection(server, fd, &vl); + if (r < 0) { + fd = safe_close(fd); + return log_error_errno(r, "Failed to add connection: %m"); + } + + vl = varlink_ref(vl); + + for (;;) { + r = varlink_process(vl); + if (r == -ENOTCONN) { + log_debug("Connection terminated."); + break; + } + if (r < 0) + return log_error_errno(r, "Failed to process connection: %m"); + if (r > 0) + continue; + + r = varlink_wait(vl, CONNECTION_IDLE_USEC); + if (r < 0) + return log_error_errno(r, "Failed to wait for connection events: %m"); + if (r == 0) + break; + } + + return 0; +} + +static int run(int argc, char *argv[]) { + usec_t start_time, listen_idle_usec, last_busy_usec = USEC_INFINITY; + _cleanup_(varlink_server_unrefp) VarlinkServer *server = NULL; + unsigned n_iterations = 0; + int m, listen_fd, r; + + log_setup(); + + m = sd_listen_fds(false); + if (m < 0) + return log_error_errno(m, "Failed to determine number of listening fds: %m"); + if (m == 0) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No socket to listen on received."); + if (m > 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Worker can only listen on a single socket at a time."); + + listen_fd = SD_LISTEN_FDS_START; + + r = fd_nonblock(listen_fd, false); + if (r < 0) + return log_error_errno(r, "Failed to turn off non-blocking mode for listening socket: %m"); + + r = varlink_server_new(&server, 0); + if (r < 0) + return log_error_errno(r, "Failed to allocate server: %m"); + + r = varlink_server_bind_method_many( + 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 bind methods: %m"); + + r = getenv_bool("USERDB_FIXED_WORKER"); + if (r < 0) + return log_error_errno(r, "Failed to parse USERDB_FIXED_WORKER: %m"); + listen_idle_usec = r ? USEC_INFINITY : LISTEN_IDLE_USEC; + + r = userdb_block_nss_systemd(true); + if (r < 0) + return log_error_errno(r, "Failed to disable userdb NSS compatibility: %m"); + + start_time = now(CLOCK_MONOTONIC); + + for (;;) { + _cleanup_close_ int fd = -1; + usec_t n; + + /* Exit the worker in regular intervals, to flush out all memory use */ + if (n_iterations++ > ITERATIONS_MAX) { + log_debug("Exiting worker, processed %u iterations, that's enough.", n_iterations); + break; + } + + n = now(CLOCK_MONOTONIC); + if (n >= usec_add(start_time, RUNTIME_MAX_USEC)) { + log_debug("Exiting worker, ran for %s, that's enough.", + FORMAT_TIMESPAN(usec_sub_unsigned(n, start_time), 0)); + break; + } + + if (last_busy_usec == USEC_INFINITY) + last_busy_usec = n; + else if (listen_idle_usec != USEC_INFINITY && n >= usec_add(last_busy_usec, listen_idle_usec)) { + log_debug("Exiting worker, been idle for %s.", + FORMAT_TIMESPAN(usec_sub_unsigned(n, last_busy_usec), 0)); + break; + } + + (void) rename_process("systemd-userwork: waiting..."); + fd = RET_NERRNO(accept4(listen_fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC)); + (void) rename_process("systemd-userwork: processing..."); + + if (fd == -EAGAIN) + continue; /* The listening socket has SO_RECVTIMEO set, hence a timeout is expected + * after a while, let's check if it's time to exit though. */ + if (fd == -EINTR) + continue; /* Might be that somebody attached via strace, let's just continue in that + * case */ + if (fd < 0) + return log_error_errno(fd, "Failed to accept() from listening socket: %m"); + + if (now(CLOCK_MONOTONIC) <= usec_add(n, PRESSURE_SLEEP_TIME_USEC)) { + /* We only slept a very short time? If so, let's see if there are more sockets + * pending, and if so, let's ask our parent for more workers */ + + r = fd_wait_for_event(listen_fd, POLLIN, 0); + if (r < 0) + return log_error_errno(r, "Failed to test for POLLIN on listening socket: %m"); + + if (FLAGS_SET(r, POLLIN)) { + pid_t parent; + + parent = getppid(); + if (parent <= 1) + return log_error_errno(SYNTHETIC_ERRNO(ESRCH), "Parent already died?"); + + if (kill(parent, SIGUSR2) < 0) + return log_error_errno(errno, "Failed to kill our own parent: %m"); + } + } + + (void) process_connection(server, TAKE_FD(fd)); + last_busy_usec = USEC_INFINITY; + } + + return 0; +} + +DEFINE_MAIN_FUNCTION(run); -- cgit v1.2.3