/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include #include #include #include #if HAVE_PIDFD_OPEN #include #endif #include #include #include #include #include "alloc-util.h" #include "audit-util.h" #include "bus-common-errors.h" #include "bus-error.h" #include "bus-internal.h" #include "bus-locator.h" #include "cap-list.h" #include "capability-util.h" #include "cgroup-setup.h" #include "creds-util.h" #include "devnum-util.h" #include "errno-util.h" #include "fd-util.h" #include "fileio.h" #include "format-util.h" #include "fs-util.h" #include "hostname-util.h" #include "locale-util.h" #include "login-util.h" #include "macro.h" #include "missing_syscall.h" #include "pam-util.h" #include "parse-util.h" #include "path-util.h" #include "percent-util.h" #include "process-util.h" #include "rlimit-util.h" #include "socket-util.h" #include "stdio-util.h" #include "strv.h" #include "terminal-util.h" #include "user-util.h" #include "userdb.h" #define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE) static int parse_caps( pam_handle_t *handle, const char *value, uint64_t *caps) { bool subtract; int r; assert(handle); assert(value); if (value[0] == '~') { subtract = true; value++; } else subtract = false; for (;;) { _cleanup_free_ char *s = NULL; uint64_t b, m; int c; /* We can't use spaces as separators here, as PAM's simplistic argument parser doesn't allow * spaces inside of arguments. We use commas instead (which is similar to cap_from_text(), * which also uses commas). */ r = extract_first_word(&value, &s, ",", EXTRACT_DONT_COALESCE_SEPARATORS); if (r < 0) return r; if (r == 0) break; c = capability_from_name(s); if (c < 0) { pam_syslog(handle, LOG_WARNING, "Unknown capability, ignoring: %s", s); continue; } m = UINT64_C(1) << c; if (!caps) continue; if (*caps == UINT64_MAX) b = subtract ? all_capabilities() : 0; else b = *caps; if (subtract) *caps = b & ~m; else *caps = b | m; } return 0; } static int parse_argv( pam_handle_t *handle, int argc, const char **argv, const char **class, const char **type, const char **desktop, bool *debug, uint64_t *default_capability_bounding_set, uint64_t *default_capability_ambient_set) { int r; assert(handle); assert(argc >= 0); assert(argc == 0 || argv); for (int i = 0; i < argc; i++) { const char *p; if ((p = startswith(argv[i], "class="))) { if (class) *class = p; } else if ((p = startswith(argv[i], "type="))) { if (type) *type = p; } else if ((p = startswith(argv[i], "desktop="))) { if (desktop) *desktop = p; } else if (streq(argv[i], "debug")) { if (debug) *debug = true; } else if ((p = startswith(argv[i], "debug="))) { r = parse_boolean(p); if (r < 0) pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p); else if (debug) *debug = r; } else if ((p = startswith(argv[i], "default-capability-bounding-set="))) { r = parse_caps(handle, p, default_capability_bounding_set); if (r < 0) pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-bounding-set= argument, ignoring: %s", p); } else if ((p = startswith(argv[i], "default-capability-ambient-set="))) { r = parse_caps(handle, p, default_capability_ambient_set); if (r < 0) pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-ambient-set= argument, ignoring: %s", p); } else pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring.", argv[i]); } return 0; } static int acquire_user_record( pam_handle_t *handle, UserRecord **ret_record) { _cleanup_(user_record_unrefp) UserRecord *ur = NULL; const char *username = NULL, *json = NULL; _cleanup_free_ char *field = NULL; int r; assert(handle); r = pam_get_user(handle, &username, NULL); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get user name: @PAMERR@"); if (isempty(username)) return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "User name not valid."); /* If pam_systemd_homed (or some other module) already acquired the user record we can reuse it * here. */ field = strjoin("systemd-user-record-", username); if (!field) return pam_log_oom(handle); r = pam_get_data(handle, field, (const void**) &json); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM user record data: @PAMERR@"); if (r == PAM_SUCCESS && json) { _cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL; /* Parse cached record */ r = sd_json_parse(json, SD_JSON_PARSE_SENSITIVE, &v, NULL, NULL); if (r < 0) return pam_syslog_errno(handle, LOG_ERR, r, "Failed to parse JSON user record: %m"); ur = user_record_new(); if (!ur) return pam_log_oom(handle); r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE); if (r < 0) return pam_syslog_errno(handle, LOG_ERR, r, "Failed to load user record: %m"); /* Safety check if cached record actually matches what we are looking for */ if (!streq_ptr(username, ur->user_name)) return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "Acquired user record does not match user name."); } else { _cleanup_free_ char *formatted = NULL; /* Request the record ourselves */ r = userdb_by_name(username, 0, &ur); if (r < 0) { pam_syslog_errno(handle, LOG_ERR, r, "Failed to get user record: %m"); return PAM_USER_UNKNOWN; } r = sd_json_variant_format(ur->json, 0, &formatted); if (r < 0) return pam_syslog_errno(handle, LOG_ERR, r, "Failed to format user JSON: %m"); /* And cache it for everyone else */ r = pam_set_data(handle, field, formatted, pam_cleanup_free); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set PAM user record data '%s': @PAMERR@", field); TAKE_PTR(formatted); } if (!uid_is_valid(ur->uid)) return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "Acquired user record does not have a UID."); if (ret_record) *ret_record = TAKE_PTR(ur); return PAM_SUCCESS; } static bool display_is_local(const char *display) { assert(display); return display[0] == ':' && ascii_isdigit(display[1]); } static int socket_from_display(const char *display) { _cleanup_free_ char *f = NULL; size_t k; char *c; union sockaddr_union sa; socklen_t sa_len; _cleanup_close_ int fd = -EBADF; int r; assert(display); if (!display_is_local(display)) return -EINVAL; k = strspn(display+1, "0123456789"); /* Try abstract socket first. */ f = new(char, STRLEN("@/tmp/.X11-unix/X") + k + 1); if (!f) return -ENOMEM; c = stpcpy(f, "@/tmp/.X11-unix/X"); memcpy(c, display+1, k); c[k] = 0; r = sockaddr_un_set_path(&sa.un, f); if (r < 0) return r; sa_len = r; fd = RET_NERRNO(socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)); if (fd < 0) return fd; r = RET_NERRNO(connect(fd, &sa.sa, sa_len)); if (r >= 0) return TAKE_FD(fd); if (r != -ECONNREFUSED) return r; /* Try also non-abstract socket. */ r = sockaddr_un_set_path(&sa.un, f + 1); if (r < 0) return r; sa_len = r; r = RET_NERRNO(connect(fd, &sa.sa, sa_len)); if (r >= 0) return TAKE_FD(fd); return r; } static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) { _cleanup_free_ char *sys_path = NULL, *tty = NULL; _cleanup_close_ int fd = -EBADF; struct ucred ucred; int v, r; dev_t display_ctty; assert(display); assert(vtnr); /* We deduce the X11 socket from the display name, then use * SO_PEERCRED to determine the X11 server process, ask for * the controlling tty of that and if it's a VC then we know * the seat and the virtual terminal. Sounds ugly, is only * semi-ugly. */ fd = socket_from_display(display); if (fd < 0) return fd; r = getpeercred(fd, &ucred); if (r < 0) return r; r = get_ctty_devnr(ucred.pid, &display_ctty); if (r < 0) return r; if (asprintf(&sys_path, "/sys/dev/char/" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(display_ctty)) < 0) return -ENOMEM; r = readlink_value(sys_path, &tty); if (r < 0) return r; v = vtnr_from_tty(tty); if (v < 0) return v; else if (v == 0) return -ENOENT; if (seat) *seat = "seat0"; *vtnr = (uint32_t) v; return 0; } static int export_legacy_dbus_address( pam_handle_t *handle, const char *runtime) { const char *s; _cleanup_free_ char *t = NULL; int r = PAM_BUF_ERR; /* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect * correctly to the bus without it. This setting matches what dbus.socket does for the user * session using 'systemctl --user set-environment'. We want to have the same configuration * in processes started from the PAM session. * * The setting of the address is guarded by the access() check because it is also possible to compile * dbus without --enable-user-session, in which case this socket is not used, and * $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access() * check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we * expect the socket to be present by the time we do this check, so we can just as well check once * here. */ s = strjoina(runtime, "/bus"); if (access(s, F_OK) < 0) return PAM_SUCCESS; if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0) return pam_log_oom(handle); r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set bus variable: @PAMERR@"); return PAM_SUCCESS; } static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) { uint64_t val; int r; if (isempty(limit)) return PAM_SUCCESS; if (streq(limit, "infinity")) { r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", UINT64_MAX); if (r < 0) return pam_bus_log_create_error(handle, r); return PAM_SUCCESS; } r = parse_permyriad(limit); if (r >= 0) { r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", UINT32_SCALE_FROM_PERMYRIAD(r)); if (r < 0) return pam_bus_log_create_error(handle, r); return PAM_SUCCESS; } r = parse_size(limit, 1024, &val); if (r >= 0) { r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val); if (r < 0) return pam_bus_log_create_error(handle, r); return PAM_SUCCESS; } pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit); return PAM_SUCCESS; } static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) { usec_t val; int r; /* No need to parse "infinity" here, it will be set by default later in scope_init() */ if (isempty(limit) || streq(limit, "infinity")) return PAM_SUCCESS; r = parse_sec(limit, &val); if (r >= 0) { r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val); if (r < 0) return pam_bus_log_create_error(handle, r); } else pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit); return PAM_SUCCESS; } static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) { uint64_t val; int r; /* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */ if (isempty(limit) || streq(limit, "infinity")) return PAM_SUCCESS; r = safe_atou64(limit, &val); if (r >= 0) { r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val); if (r < 0) return pam_bus_log_create_error(handle, r); } else pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit); return PAM_SUCCESS; } static int append_session_cpu_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) { uint64_t val; int r; if (isempty(limit)) return PAM_SUCCESS; r = cg_cpu_weight_parse(limit, &val); if (r < 0) pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit); else { r = sd_bus_message_append(m, "(sv)", "CPUWeight", "t", val); if (r < 0) return pam_bus_log_create_error(handle, r); } return PAM_SUCCESS; } static int append_session_io_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) { uint64_t val; int r; if (isempty(limit)) return PAM_SUCCESS; r = cg_weight_parse(limit, &val); if (r < 0) pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit); else { r = sd_bus_message_append(m, "(sv)", "IOWeight", "t", val); if (r < 0) return pam_bus_log_create_error(handle, r); } return PAM_SUCCESS; } static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) { const char *v; assert(handle); assert(key); /* Looks for an environment variable, preferably in the environment block associated with the * specified PAM handle, falling back to the process' block instead. Why check both? Because we want * to permit configuration of session properties from unit files that invoke PAM services, so that * PAM services don't have to be reworked to set systemd-specific properties, but these properties * can still be set from the unit file Environment= block. */ v = pam_getenv(handle, key); if (!isempty(v)) return v; /* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally * they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they * currently don't (to be precise, they clean up the environment they pass to their children, but * not their own environ[]). */ v = secure_getenv(key); if (!isempty(v)) return v; return fallback; } static bool getenv_harder_bool(pam_handle_t *handle, const char *key, bool fallback) { const char *v; int r; assert(handle); assert(key); v = getenv_harder(handle, key, NULL); if (isempty(v)) return fallback; r = parse_boolean(v); if (r < 0) { pam_syslog(handle, LOG_ERR, "Boolean environment variable value of '%s' is not valid: %s", key, v); return fallback; } return r; } static int update_environment(pam_handle_t *handle, const char *key, const char *value) { int r; assert(handle); assert(key); /* Updates the environment, but only if there's actually a value set. Also, log about errors */ if (isempty(value)) return PAM_SUCCESS; r = pam_misc_setenv(handle, key, value, 0); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set environment variable %s: @PAMERR@", key); return PAM_SUCCESS; } static int propagate_credential_to_environment(pam_handle_t *handle, const char *credential, const char *varname) { int r; assert(handle); assert(credential); assert(varname); _cleanup_free_ char *value = NULL; /* Read a service credential, and propagate it into an environment variable */ r = read_credential(credential, (void**) &value, /* ret_size= */ NULL); if (r < 0) { log_debug_errno(r, "Failed to read credential '%s', ignoring: %m", credential); return PAM_SUCCESS; } r = pam_misc_setenv(handle, varname, value, 0); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set environment variable %s: @PAMERR@", varname); return PAM_SUCCESS; } static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) { struct stat st; assert(handle); assert(path); /* Some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually * set up properly for us. This is supposed to provide a careful safety net for supporting su/sudo * type transitions: in that case the UID changes, but the session and thus the user owning it * doesn't change. Since the $XDG_RUNTIME_DIR lifecycle is bound to the session's user being logged * in at least once we should be particularly careful when setting the environment variable, since * otherwise we might end up setting $XDG_RUNTIME_DIR to some directory owned by the wrong user. */ if (!path_is_absolute(path)) { pam_syslog(handle, LOG_ERR, "Provided runtime directory '%s' is not absolute.", path); goto fail; } if (lstat(path, &st) < 0) { pam_syslog_errno(handle, LOG_ERR, errno, "Failed to stat() runtime directory '%s': %m", path); goto fail; } if (!S_ISDIR(st.st_mode)) { pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path); goto fail; } if (st.st_uid != uid) { pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid); goto fail; } return true; fail: pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order."); return false; } static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) { int r; assert(handle); assert(e); r = pam_putenv(handle, e); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set PAM environment variable %s: @PAMERR@", e); pam_debug_syslog(handle, debug, "PAM environment variable %s set based on user record.", e); return PAM_SUCCESS; } static int apply_user_record_settings( pam_handle_t *handle, UserRecord *ur, bool debug, uint64_t default_capability_bounding_set, uint64_t default_capability_ambient_set) { _cleanup_strv_free_ char **langs = NULL; int r; assert(handle); assert(ur); if (ur->umask != MODE_INVALID) { umask(ur->umask); pam_debug_syslog(handle, debug, "Set user umask to %04o based on user record.", ur->umask); } STRV_FOREACH(i, ur->environment) { r = pam_putenv_and_log(handle, *i, debug); if (r != PAM_SUCCESS) return r; } if (ur->email_address) { _cleanup_free_ char *joined = NULL; joined = strjoin("EMAIL=", ur->email_address); if (!joined) return pam_log_oom(handle); r = pam_putenv_and_log(handle, joined, debug); if (r != PAM_SUCCESS) return r; } if (ur->time_zone) { if (!timezone_is_valid(ur->time_zone, LOG_DEBUG)) pam_debug_syslog(handle, debug, "Time zone specified in user record is not valid locally, not setting $TZ."); else { _cleanup_free_ char *joined = NULL; joined = strjoin("TZ=:", ur->time_zone); if (!joined) return pam_log_oom(handle); r = pam_putenv_and_log(handle, joined, debug); if (r != PAM_SUCCESS) return r; } } r = user_record_languages(ur, &langs); if (r < 0) pam_syslog_errno(handle, LOG_ERR, r, "Failed to acquire user's language preferences, ignoring: %m"); else if (strv_isempty(langs)) ; /* User has no preference set so we do nothing */ else if (locale_is_installed(langs[0]) <= 0) pam_debug_syslog(handle, debug, "Preferred languages specified in user record are not installed locally, not setting $LANG or $LANGUAGE."); else { _cleanup_free_ char *lang = NULL; lang = strjoin("LANG=", langs[0]); if (!lang) return pam_log_oom(handle); r = pam_putenv_and_log(handle, lang, debug); if (r != PAM_SUCCESS) return r; if (strv_length(langs) > 1) { _cleanup_free_ char *joined = NULL, *language = NULL; joined = strv_join(langs, ":"); if (!joined) return pam_log_oom(handle); language = strjoin("LANGUAGE=", joined); if (!language) return pam_log_oom(handle); r = pam_putenv_and_log(handle, language, debug); if (r != PAM_SUCCESS) return r; } } if (nice_is_valid(ur->nice_level)) { if (nice(ur->nice_level) < 0) pam_syslog_errno(handle, LOG_ERR, errno, "Failed to set nice level to %i, ignoring: %m", ur->nice_level); else pam_debug_syslog(handle, debug, "Nice level set to %i, based on user record.", ur->nice_level); } for (int rl = 0; rl < _RLIMIT_MAX; rl++) { if (!ur->rlimits[rl]) continue; r = setrlimit_closest(rl, ur->rlimits[rl]); if (r < 0) pam_syslog_errno(handle, LOG_ERR, r, "Failed to set resource limit %s, ignoring: %m", rlimit_to_string(rl)); else pam_debug_syslog(handle, debug, "Resource limit %s set, based on user record.", rlimit_to_string(rl)); } uint64_t a, b; a = user_record_capability_ambient_set(ur); if (a == UINT64_MAX) a = default_capability_ambient_set; b = user_record_capability_bounding_set(ur); if (b == UINT64_MAX) b = default_capability_bounding_set; if (a != UINT64_MAX && a != 0) { a &= b; r = capability_ambient_set_apply(a, /* also_inherit= */ true); if (r < 0) pam_syslog_errno(handle, LOG_ERR, r, "Failed to set ambient capabilities, ignoring: %m"); } if (b != UINT64_MAX && !cap_test_all(b)) { r = capability_bounding_set_drop(b, /* right_now= */ false); if (r < 0) pam_syslog_errno(handle, LOG_ERR, r, "Failed to set bounding capabilities, ignoring: %m"); } return PAM_SUCCESS; } static int configure_runtime_directory( pam_handle_t *handle, UserRecord *ur, const char *rt) { int r; assert(handle); assert(ur); assert(rt); if (!validate_runtime_directory(handle, rt, ur->uid)) return PAM_SUCCESS; r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set runtime dir: @PAMERR@"); return export_legacy_dbus_address(handle, rt); } static uint64_t pick_default_capability_ambient_set( UserRecord *ur, const char *service, const char *seat) { /* If not configured otherwise, let's enable CAP_WAKE_ALARM for regular users when logging in on a * seat (i.e. when they are present physically on the device), or when invoked for the systemd --user * instances. This allows desktops to install CAP_WAKE_ALARM to implement alarm clock apps without * much fuss. */ return ur && user_record_disposition(ur) == USER_REGULAR && (streq_ptr(service, "systemd-user") || !isempty(seat)) ? (UINT64_C(1) << CAP_WAKE_ALARM) : UINT64_MAX; } typedef struct SessionContext { const uid_t uid; const pid_t pid; const char *service; const char *type; const char *class; const char *desktop; const char *seat; const uint32_t vtnr; const char *tty; const char *display; const bool remote; const char *remote_user; const char *remote_host; const char *memory_max; const char *tasks_max; const char *cpu_weight; const char *io_weight; const char *runtime_max_sec; } SessionContext; static int create_session_message( sd_bus *bus, pam_handle_t *handle, const SessionContext *context, bool avoid_pidfd, sd_bus_message **ret) { _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL; _cleanup_close_ int pidfd = -EBADF; int r; assert(bus); assert(handle); assert(context); assert(ret); if (!avoid_pidfd) { pidfd = pidfd_open(getpid_cached(), 0); if (pidfd < 0 && !ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno)) return -errno; } r = bus_message_new_method_call(bus, &m, bus_login_mgr, pidfd >= 0 ? "CreateSessionWithPIDFD" : "CreateSession"); if (r < 0) return r; r = sd_bus_message_append(m, pidfd >= 0 ? "uhsssssussbss" : "uusssssussbss", (uint32_t) context->uid, pidfd >= 0 ? pidfd : context->pid, context->service, context->type, context->class, context->desktop, context->seat, context->vtnr, context->tty, context->display, context->remote, context->remote_user, context->remote_host); if (r < 0) return r; if (pidfd >= 0) { r = sd_bus_message_append(m, "t", UINT64_C(0)); if (r < 0) return r; } r = sd_bus_message_open_container(m, 'a', "(sv)"); if (r < 0) return r; r = append_session_memory_max(handle, m, context->memory_max); if (r != PAM_SUCCESS) return r; r = append_session_runtime_max_sec(handle, m, context->runtime_max_sec); if (r != PAM_SUCCESS) return r; r = append_session_tasks_max(handle, m, context->tasks_max); if (r != PAM_SUCCESS) return r; r = append_session_cpu_weight(handle, m, context->cpu_weight); if (r != PAM_SUCCESS) return r; r = append_session_io_weight(handle, m, context->io_weight); if (r != PAM_SUCCESS) return r; r = sd_bus_message_close_container(m); if (r < 0) return r; *ret = TAKE_PTR(m); return 0; } _public_ PAM_EXTERN int pam_sm_open_session( pam_handle_t *handle, int flags, int argc, const char **argv) { /* Let's release the D-Bus connection once this function exits, after all the session might live * quite a long time, and we are not going to process the bus connection in that time, so let's * better close before the daemon kicks us off because we are not processing anything. */ _cleanup_(pam_bus_data_disconnectp) PamBusData *d = NULL; _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL; const char *id, *object_path, *runtime_path, *service = NULL, *tty = NULL, *display = NULL, *remote_user = NULL, *remote_host = NULL, *seat = NULL, *type = NULL, *class = NULL, *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL, *memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL; uint64_t default_capability_bounding_set = UINT64_MAX, default_capability_ambient_set = UINT64_MAX; _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; _cleanup_(user_record_unrefp) UserRecord *ur = NULL; int session_fd = -EBADF, existing, r; bool debug = false, remote, incomplete; uint32_t vtnr = 0; uid_t original_uid; assert(handle); pam_log_setup(); if (parse_argv(handle, argc, argv, &class_pam, &type_pam, &desktop_pam, &debug, &default_capability_bounding_set, &default_capability_ambient_set) < 0) return PAM_SESSION_ERR; pam_debug_syslog(handle, debug, "pam-systemd initializing"); r = acquire_user_record(handle, &ur); if (r != PAM_SUCCESS) return r; /* Make most of this a NOP on non-logind systems */ if (!logind_running()) goto success; r = pam_get_item_many( handle, PAM_SERVICE, &service, PAM_XDISPLAY, &display, PAM_TTY, &tty, PAM_RUSER, &remote_user, PAM_RHOST, &remote_host); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM items: @PAMERR@"); seat = getenv_harder(handle, "XDG_SEAT", NULL); cvtnr = getenv_harder(handle, "XDG_VTNR", NULL); type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam); class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam); desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam); incomplete = getenv_harder_bool(handle, "XDG_SESSION_INCOMPLETE", false); if (streq_ptr(service, "systemd-user")) { /* If we detect that we are running in the "systemd-user" PAM stack, then let's patch the class to * 'manager' if not set, simply for robustness reasons. */ type = "unspecified"; class = IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) ? "manager-early" : "manager"; tty = NULL; } else if (tty && strchr(tty, ':')) { /* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things * and don't pretend that an X display was a tty. */ if (isempty(display)) display = tty; tty = NULL; } else if (streq_ptr(tty, "cron")) { /* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but * probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set * (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked * off processes.) */ type = "unspecified"; class = "background"; tty = NULL; } else if (streq_ptr(tty, "ssh")) { /* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further * details look for "PAM_TTY_KLUDGE" in the openssh sources). */ type = "tty"; class = "user"; tty = NULL; /* This one is particularly sad, as this means that ssh sessions — even though usually * associated with a pty — won't be tracked by their tty in logind. This is because ssh * does the PAM session registration early for new connections, and registers a pty only * much later (this is because it doesn't know yet if it needs one at all, as whether to * register a pty or not is negotiated much later in the protocol). */ } else if (tty) /* Chop off leading /dev prefix that some clients specify, but others do not. */ tty = skip_dev_prefix(tty); /* If this fails vtnr will be 0, that's intended */ if (!isempty(cvtnr)) (void) safe_atou32(cvtnr, &vtnr); if (!isempty(display) && !vtnr) { if (isempty(seat)) (void) get_seat_from_display(display, &seat, &vtnr); else if (streq(seat, "seat0")) (void) get_seat_from_display(display, NULL, &vtnr); } if (seat && !streq(seat, "seat0") && vtnr != 0) { pam_debug_syslog(handle, debug, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat); vtnr = 0; } if (isempty(type)) type = !isempty(display) ? "x11" : !isempty(tty) ? "tty" : "unspecified"; if (isempty(class)) class = streq(type, "unspecified") ? "background" : ((IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) && streq(type, "tty")) ? "user-early" : "user"); if (incomplete) { if (streq(class, "user")) class = "user-incomplete"; else pam_syslog_pam_error(handle, LOG_WARNING, 0, "PAM session of class '%s' is incomplete, which is not supported, ignoring.", class); } remote = !isempty(remote_host) && !is_localhost(remote_host); r = pam_get_data(handle, "systemd.memory_max", (const void **)&memory_max); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.memory_max data: @PAMERR@"); r = pam_get_data(handle, "systemd.tasks_max", (const void **)&tasks_max); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.tasks_max data: @PAMERR@"); r = pam_get_data(handle, "systemd.cpu_weight", (const void **)&cpu_weight); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.cpu_weight data: @PAMERR@"); r = pam_get_data(handle, "systemd.io_weight", (const void **)&io_weight); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.io_weight data: @PAMERR@"); r = pam_get_data(handle, "systemd.runtime_max_sec", (const void **)&runtime_max_sec); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.runtime_max_sec data: @PAMERR@"); /* Talk to logind over the message bus */ r = pam_acquire_bus_connection(handle, "pam-systemd", debug, &bus, &d); if (r != PAM_SUCCESS) return r; pam_debug_syslog(handle, debug, "Asking logind to create session: " "uid="UID_FMT" pid="PID_FMT" service=%s type=%s class=%s desktop=%s seat=%s vtnr=%"PRIu32" tty=%s display=%s remote=%s remote_user=%s remote_host=%s", ur->uid, getpid_cached(), strempty(service), type, class, strempty(desktop), strempty(seat), vtnr, strempty(tty), strempty(display), yes_no(remote), strempty(remote_user), strempty(remote_host)); pam_debug_syslog(handle, debug, "Session limits: " "memory_max=%s tasks_max=%s cpu_weight=%s io_weight=%s runtime_max_sec=%s", strna(memory_max), strna(tasks_max), strna(cpu_weight), strna(io_weight), strna(runtime_max_sec)); const SessionContext context = { .uid = ur->uid, .pid = 0, .service = service, .type = type, .class = class, .desktop = desktop, .seat = seat, .vtnr = vtnr, .tty = tty, .display = display, .remote = remote, .remote_user = remote_user, .remote_host = remote_host, .memory_max = memory_max, .tasks_max = tasks_max, .cpu_weight = cpu_weight, .io_weight = io_weight, .runtime_max_sec = runtime_max_sec, }; r = create_session_message(bus, handle, &context, /* avoid_pidfd = */ false, &m); if (r < 0) return pam_bus_log_create_error(handle, r); r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply); if (r < 0 && sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD)) { sd_bus_error_free(&error); pam_debug_syslog(handle, debug, "CreateSessionWithPIDFD() API is not available, retrying with CreateSession()."); m = sd_bus_message_unref(m); r = create_session_message(bus, handle, &context, /* avoid_pidfd = */ true, &m); if (r < 0) return pam_bus_log_create_error(handle, r); r = sd_bus_call(bus, m, LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply); } if (r < 0) { if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) { /* We are already in a session, don't do anything */ pam_debug_syslog(handle, debug, "Not creating session: %s", bus_error_message(&error, r)); goto success; } pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r)); return PAM_SESSION_ERR; } r = sd_bus_message_read(reply, "soshusub", &id, &object_path, &runtime_path, &session_fd, &original_uid, &seat, &vtnr, &existing); if (r < 0) return pam_bus_log_parse_error(handle, r); pam_debug_syslog(handle, debug, "Reply from logind: " "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u", id, object_path, runtime_path, session_fd, seat, vtnr, original_uid); /* Please update manager_default_environment() in core/manager.c accordingly if more session envvars * shall be added. */ r = update_environment(handle, "XDG_SESSION_ID", id); if (r != PAM_SUCCESS) return r; if (original_uid == ur->uid) { /* Don't set $XDG_RUNTIME_DIR if the user we now authenticated for does not match the * original user of the session. We do this in order not to result in privileged apps * clobbering the runtime directory unnecessarily. */ r = configure_runtime_directory(handle, ur, runtime_path); if (r != PAM_SUCCESS) return r; } /* Most likely we got the session/type/class from environment variables, but might have gotten the data * somewhere else (for example PAM module parameters). Let's now update the environment variables, so that this * data is inherited into the session processes, and programs can rely on them to be initialized. */ r = update_environment(handle, "XDG_SESSION_TYPE", type); if (r != PAM_SUCCESS) return r; r = update_environment(handle, "XDG_SESSION_CLASS", class); if (r != PAM_SUCCESS) return r; r = update_environment(handle, "XDG_SESSION_DESKTOP", desktop); if (r != PAM_SUCCESS) return r; r = update_environment(handle, "XDG_SEAT", seat); if (r != PAM_SUCCESS) return r; static const char *const propagate[] = { "shell.prompt.prefix", "SHELL_PROMPT_PREFIX", "shell.prompt.suffix", "SHELL_PROMPT_SUFFIX", "shell.welcome", "SHELL_WELCOME", NULL }; STRV_FOREACH_PAIR(k, v, propagate) { r = propagate_credential_to_environment(handle, *k, *v); if (r != PAM_SUCCESS) return r; } if (vtnr > 0) { char buf[DECIMAL_STR_MAX(vtnr)]; sprintf(buf, "%u", vtnr); r = update_environment(handle, "XDG_VTNR", buf); if (r != PAM_SUCCESS) return r; } r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to install existing flag: @PAMERR@"); if (session_fd >= 0) { _cleanup_close_ int fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3); if (fd < 0) return pam_syslog_errno(handle, LOG_ERR, errno, "Failed to dup session fd: %m"); r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(fd), NULL); if (r != PAM_SUCCESS) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to install session fd: @PAMERR@"); TAKE_FD(fd); } success: if (default_capability_ambient_set == UINT64_MAX) default_capability_ambient_set = pick_default_capability_ambient_set(ur, service, seat); return apply_user_record_settings(handle, ur, debug, default_capability_bounding_set, default_capability_ambient_set); } _public_ PAM_EXTERN int pam_sm_close_session( pam_handle_t *handle, int flags, int argc, const char **argv) { const void *existing = NULL; bool debug = false; const char *id; int r; assert(handle); pam_log_setup(); if (parse_argv(handle, argc, argv, NULL, NULL, NULL, &debug, NULL, NULL) < 0) return PAM_SESSION_ERR; pam_debug_syslog(handle, debug, "pam-systemd shutting down"); /* Only release session if it wasn't pre-existing when we * tried to create it */ r = pam_get_data(handle, "systemd.existing", &existing); if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM systemd.existing data: @PAMERR@"); id = pam_getenv(handle, "XDG_SESSION_ID"); if (id && !existing) { _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; /* Before we go and close the FIFO we need to tell logind that this is a clean session * shutdown, so that it doesn't just go and slaughter us immediately after closing the fd */ r = pam_acquire_bus_connection(handle, "pam-systemd", debug, &bus, NULL); if (r != PAM_SUCCESS) return r; r = bus_call_method(bus, bus_login_mgr, "ReleaseSession", &error, NULL, "s", id); if (r < 0) return pam_syslog_pam_error(handle, LOG_ERR, PAM_SESSION_ERR, "Failed to release session: %s", bus_error_message(&error, r)); } /* Note that we are knowingly leaking the FIFO fd here. This way, logind can watch us die. If we * closed it here it would not have any clue when that is completed. Given that one cannot really * have multiple PAM sessions open from the same process this means we will leak one FD at max. */ return PAM_SUCCESS; }