/* SPDX-License-Identifier: LGPL-2.1+ */ /*** Copyright © 2015 Werner Fink ***/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "ask-password-api.h" #include "conf-parser.h" #include "def.h" #include "dirent-util.h" #include "exit-status.h" #include "fd-util.h" #include "fileio.h" #include "hashmap.h" #include "io-util.h" #include "macro.h" #include "mkdir.h" #include "path-util.h" #include "process-util.h" #include "signal-util.h" #include "socket-util.h" #include "string-util.h" #include "strv.h" #include "terminal-util.h" #include "util.h" #include "utmp-wtmp.h" static enum { ACTION_LIST, ACTION_QUERY, ACTION_WATCH, ACTION_WALL } arg_action = ACTION_QUERY; static bool arg_plymouth = false; static bool arg_console = false; static const char *arg_device = NULL; static int ask_password_plymouth( const char *message, usec_t until, AskPasswordFlags flags, const char *flag_file, char ***ret) { static const union sockaddr_union sa = PLYMOUTH_SOCKET; _cleanup_close_ int fd = -1, notify = -1; _cleanup_free_ char *packet = NULL; ssize_t k; int r, n; struct pollfd pollfd[2] = {}; char buffer[LINE_MAX]; size_t p = 0; enum { POLL_SOCKET, POLL_INOTIFY }; assert(ret); if (flag_file) { notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK); if (notify < 0) return -errno; r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */ if (r < 0) return -errno; } fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (fd < 0) return -errno; r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)); if (r < 0) return -errno; if (flags & ASK_PASSWORD_ACCEPT_CACHED) { packet = strdup("c"); n = 1; } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) packet = NULL; if (!packet) return -ENOMEM; r = loop_write(fd, packet, n + 1, true); if (r < 0) return r; pollfd[POLL_SOCKET].fd = fd; pollfd[POLL_SOCKET].events = POLLIN; pollfd[POLL_INOTIFY].fd = notify; pollfd[POLL_INOTIFY].events = POLLIN; for (;;) { int sleep_for = -1, j; if (until > 0) { usec_t y; y = now(CLOCK_MONOTONIC); if (y > until) { r = -ETIME; goto finish; } sleep_for = (int) ((until - y) / USEC_PER_MSEC); } if (flag_file && access(flag_file, F_OK) < 0) { r = -errno; goto finish; } j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for); if (j < 0) { if (errno == EINTR) continue; r = -errno; goto finish; } else if (j == 0) { r = -ETIME; goto finish; } if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0) (void) flush_fd(notify); if (pollfd[POLL_SOCKET].revents == 0) continue; k = read(fd, buffer + p, sizeof(buffer) - p); if (k < 0) { if (IN_SET(errno, EINTR, EAGAIN)) continue; r = -errno; goto finish; } else if (k == 0) { r = -EIO; goto finish; } p += k; if (p < 1) continue; if (buffer[0] == 5) { if (flags & ASK_PASSWORD_ACCEPT_CACHED) { /* Hmm, first try with cached * passwords failed, so let's retry * with a normal password request */ packet = mfree(packet); if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) { r = -ENOMEM; goto finish; } r = loop_write(fd, packet, n+1, true); if (r < 0) goto finish; flags &= ~ASK_PASSWORD_ACCEPT_CACHED; p = 0; continue; } /* No password, because UI not shown */ r = -ENOENT; goto finish; } else if (IN_SET(buffer[0], 2, 9)) { uint32_t size; char **l; /* One or more answers */ if (p < 5) continue; memcpy(&size, buffer+1, sizeof(size)); size = le32toh(size); if (size + 5 > sizeof(buffer)) { r = -EIO; goto finish; } if (p-5 < size) continue; l = strv_parse_nulstr(buffer + 5, size); if (!l) { r = -ENOMEM; goto finish; } *ret = l; break; } else { /* Unknown packet */ r = -EIO; goto finish; } } r = 0; finish: explicit_bzero(buffer, sizeof(buffer)); return r; } static int send_passwords(const char *socket_name, char **passwords) { _cleanup_free_ char *packet = NULL; _cleanup_close_ int socket_fd = -1; union sockaddr_union sa = { .un.sun_family = AF_UNIX }; size_t packet_length = 1; char **p, *d; ssize_t n; int r; assert(socket_name); STRV_FOREACH(p, passwords) packet_length += strlen(*p) + 1; packet = new(char, packet_length); if (!packet) return -ENOMEM; packet[0] = '+'; d = packet + 1; STRV_FOREACH(p, passwords) d = stpcpy(d, *p) + 1; socket_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0); if (socket_fd < 0) { r = log_debug_errno(errno, "socket(): %m"); goto finish; } strncpy(sa.un.sun_path, socket_name, sizeof(sa.un.sun_path)); n = sendto(socket_fd, packet, packet_length, MSG_NOSIGNAL, &sa.sa, SOCKADDR_UN_LEN(sa.un)); if (n < 0) { r = log_debug_errno(errno, "sendto(): %m"); goto finish; } r = (int) n; finish: explicit_bzero(packet, packet_length); return r; } static int parse_password(const char *filename, char **wall) { _cleanup_free_ char *socket_name = NULL, *message = NULL; bool accept_cached = false, echo = false; uint64_t not_after = 0; unsigned pid = 0; const ConfigTableItem items[] = { { "Ask", "Socket", config_parse_string, 0, &socket_name }, { "Ask", "NotAfter", config_parse_uint64, 0, ¬_after }, { "Ask", "Message", config_parse_string, 0, &message }, { "Ask", "PID", config_parse_unsigned, 0, &pid }, { "Ask", "AcceptCached", config_parse_bool, 0, &accept_cached }, { "Ask", "Echo", config_parse_bool, 0, &echo }, {} }; int r; assert(filename); r = config_parse(NULL, filename, NULL, NULL, config_item_table_lookup, items, CONFIG_PARSE_RELAXED|CONFIG_PARSE_WARN, NULL); if (r < 0) return r; if (!socket_name) { log_error("Invalid password file %s", filename); return -EBADMSG; } if (not_after > 0 && now(CLOCK_MONOTONIC) > not_after) return 0; if (pid > 0 && !pid_is_alive(pid)) return 0; if (arg_action == ACTION_LIST) printf("'%s' (PID %u)\n", message, pid); else if (arg_action == ACTION_WALL) { char *_wall; if (asprintf(&_wall, "%s%sPassword entry required for \'%s\' (PID %u).\r\n" "Please enter password with the systemd-tty-ask-password-agent tool!", strempty(*wall), *wall ? "\r\n\r\n" : "", message, pid) < 0) return log_oom(); free(*wall); *wall = _wall; } else { _cleanup_strv_free_erase_ char **passwords = NULL; assert(IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH)); if (access(socket_name, W_OK) < 0) { if (arg_action == ACTION_QUERY) log_info("Not querying '%s' (PID %u), lacking privileges.", message, pid); return 0; } if (arg_plymouth) r = ask_password_plymouth(message, not_after, accept_cached ? ASK_PASSWORD_ACCEPT_CACHED : 0, filename, &passwords); else { char *password = NULL; int tty_fd = -1; if (arg_console) { const char *con = arg_device ?: "/dev/console"; tty_fd = acquire_terminal(con, ACQUIRE_TERMINAL_WAIT, USEC_INFINITY); if (tty_fd < 0) return log_error_errno(tty_fd, "Failed to acquire %s: %m", con); r = reset_terminal_fd(tty_fd, true); if (r < 0) log_warning_errno(r, "Failed to reset terminal, ignoring: %m"); } r = ask_password_tty(tty_fd, message, NULL, not_after, (echo ? ASK_PASSWORD_ECHO : 0) | (arg_console ? ASK_PASSWORD_CONSOLE_COLOR : 0), filename, &password); if (arg_console) { tty_fd = safe_close(tty_fd); release_terminal(); } if (r >= 0) r = strv_push(&passwords, password); if (r < 0) string_free_erase(password); } /* If the query went away, that's OK */ if (IN_SET(r, -ETIME, -ENOENT)) return 0; if (r < 0) return log_error_errno(r, "Failed to query password: %m"); r = send_passwords(socket_name, passwords); if (r < 0) return log_error_errno(r, "Failed to send: %m"); } return 0; } static int wall_tty_block(void) { _cleanup_free_ char *p = NULL; dev_t devnr; int fd, r; r = get_ctty_devnr(0, &devnr); if (r == -ENXIO) /* We have no controlling tty */ return -ENOTTY; if (r < 0) return log_error_errno(r, "Failed to get controlling TTY: %m"); if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(devnr), minor(devnr)) < 0) return log_oom(); (void) mkdir_parents_label(p, 0700); (void) mkfifo(p, 0600); fd = open(p, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); if (fd < 0) return log_debug_errno(errno, "Failed to open %s: %m", p); return fd; } static bool wall_tty_match(const char *path, void *userdata) { _cleanup_free_ char *p = NULL; _cleanup_close_ int fd = -1; struct stat st; if (!path_is_absolute(path)) path = strjoina("/dev/", path); if (lstat(path, &st) < 0) { log_debug_errno(errno, "Failed to stat %s: %m", path); return true; } if (!S_ISCHR(st.st_mode)) { log_debug("%s is not a character device.", path); return true; } /* We use named pipes to ensure that wall messages suggesting * password entry are not printed over password prompts * already shown. We use the fact here that opening a pipe in * non-blocking mode for write-only will succeed only if * there's some writer behind it. Using pipes has the * advantage that the block will automatically go away if the * process dies. */ if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(st.st_rdev), minor(st.st_rdev)) < 0) { log_oom(); return true; } fd = open(p, O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); if (fd < 0) { log_debug_errno(errno, "Failed to open the wall pipe: %m"); return 1; } /* What, we managed to open the pipe? Then this tty is filtered. */ return 0; } static int show_passwords(void) { _cleanup_closedir_ DIR *d; struct dirent *de; int r = 0; d = opendir("/run/systemd/ask-password"); if (!d) { if (errno == ENOENT) return 0; return log_error_errno(errno, "Failed to open /run/systemd/ask-password: %m"); } FOREACH_DIRENT_ALL(de, d, return log_error_errno(errno, "Failed to read directory: %m")) { _cleanup_free_ char *p = NULL, *wall = NULL; int q; /* We only support /dev on tmpfs, hence we can rely on * d_type to be reliable */ if (de->d_type != DT_REG) continue; if (hidden_or_backup_file(de->d_name)) continue; if (!startswith(de->d_name, "ask.")) continue; p = strappend("/run/systemd/ask-password/", de->d_name); if (!p) return log_oom(); q = parse_password(p, &wall); if (q < 0 && r == 0) r = q; if (wall) (void) utmp_wall(wall, NULL, NULL, wall_tty_match, NULL); } return r; } static int watch_passwords(void) { enum { FD_INOTIFY, FD_SIGNAL, _FD_MAX }; _cleanup_close_ int notify = -1, signal_fd = -1, tty_block_fd = -1; struct pollfd pollfd[_FD_MAX] = {}; sigset_t mask; int r; tty_block_fd = wall_tty_block(); (void) mkdir_p_label("/run/systemd/ask-password", 0755); notify = inotify_init1(IN_CLOEXEC); if (notify < 0) return log_error_errno(errno, "Failed to allocate directory watch: %m"); if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_CLOSE_WRITE|IN_MOVED_TO) < 0) return log_error_errno(errno, "Failed to add /run/systemd/ask-password to directory watch: %m"); assert_se(sigemptyset(&mask) >= 0); assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0); assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) >= 0); signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC); if (signal_fd < 0) return log_error_errno(errno, "Failed to allocate signal file descriptor: %m"); pollfd[FD_INOTIFY].fd = notify; pollfd[FD_INOTIFY].events = POLLIN; pollfd[FD_SIGNAL].fd = signal_fd; pollfd[FD_SIGNAL].events = POLLIN; for (;;) { r = show_passwords(); if (r < 0) log_error_errno(r, "Failed to show password: %m"); if (poll(pollfd, _FD_MAX, -1) < 0) { if (errno == EINTR) continue; return -errno; } if (pollfd[FD_INOTIFY].revents != 0) (void) flush_fd(notify); if (pollfd[FD_SIGNAL].revents != 0) break; } return 0; } static void help(void) { printf("%s [OPTIONS...]\n\n" "Process system password requests.\n\n" " -h --help Show this help\n" " --version Show package version\n" " --list Show pending password requests\n" " --query Process pending password requests\n" " --watch Continuously process password requests\n" " --wall Continuously forward password requests to wall\n" " --plymouth Ask question with Plymouth instead of on TTY\n" " --console Ask question on /dev/console instead of current TTY\n", program_invocation_short_name); } static int parse_argv(int argc, char *argv[]) { enum { ARG_LIST = 0x100, ARG_QUERY, ARG_WATCH, ARG_WALL, ARG_PLYMOUTH, ARG_CONSOLE, ARG_VERSION }; static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, ARG_VERSION }, { "list", no_argument, NULL, ARG_LIST }, { "query", no_argument, NULL, ARG_QUERY }, { "watch", no_argument, NULL, ARG_WATCH }, { "wall", no_argument, NULL, ARG_WALL }, { "plymouth", no_argument, NULL, ARG_PLYMOUTH }, { "console", optional_argument, NULL, ARG_CONSOLE }, {} }; int c; assert(argc >= 0); assert(argv); while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) switch (c) { case 'h': help(); return 0; case ARG_VERSION: return version(); case ARG_LIST: arg_action = ACTION_LIST; break; case ARG_QUERY: arg_action = ACTION_QUERY; break; case ARG_WATCH: arg_action = ACTION_WATCH; break; case ARG_WALL: arg_action = ACTION_WALL; break; case ARG_PLYMOUTH: arg_plymouth = true; break; case ARG_CONSOLE: arg_console = true; if (optarg) { if (isempty(optarg)) { log_error("Empty console device path is not allowed."); return -EINVAL; } arg_device = optarg; } break; case '?': return -EINVAL; default: assert_not_reached("Unhandled option"); } if (optind != argc) { log_error("%s takes no arguments.", program_invocation_short_name); return -EINVAL; } if (arg_plymouth || arg_console) { if (!IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH)) { log_error("Options --query and --watch conflict."); return -EINVAL; } if (arg_plymouth && arg_console) { log_error("Options --plymouth and --console conflict."); return -EINVAL; } } return 1; } /* * To be able to ask on all terminal devices of /dev/console * the devices are collected. If more than one device is found, * then on each of the terminals a inquiring task is forked. * Every task has its own session and its own controlling terminal. * If one of the tasks does handle a password, the remaining tasks * will be terminated. */ static int ask_on_this_console(const char *tty, pid_t *ret_pid, int argc, char *argv[]) { struct sigaction sig = { .sa_handler = nop_signal_handler, .sa_flags = SA_NOCLDSTOP | SA_RESTART, }; pid_t pid; int r; assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD, -1) >= 0); assert_se(sigemptyset(&sig.sa_mask) >= 0); assert_se(sigaction(SIGCHLD, &sig, NULL) >= 0); sig.sa_handler = SIG_DFL; assert_se(sigaction(SIGHUP, &sig, NULL) >= 0); r = safe_fork("(sd-passwd)", FORK_RESET_SIGNALS|FORK_LOG, &pid); if (r < 0) return r; if (r == 0) { int ac; assert_se(prctl(PR_SET_PDEATHSIG, SIGHUP) >= 0); for (ac = 0; ac < argc; ac++) { if (streq(argv[ac], "--console")) { argv[ac] = strjoina("--console=", tty); break; } } assert(ac < argc); execv(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, argv); _exit(EXIT_FAILURE); } *ret_pid = pid; return 0; } static void terminate_agents(Set *pids) { struct timespec ts; siginfo_t status = {}; sigset_t set; Iterator i; void *p; int r, signum; /* * Request termination of the remaining processes as those * are not required anymore. */ SET_FOREACH(p, pids, i) (void) kill(PTR_TO_PID(p), SIGTERM); /* * Collect the processes which have go away. */ assert_se(sigemptyset(&set) >= 0); assert_se(sigaddset(&set, SIGCHLD) >= 0); timespec_store(&ts, 50 * USEC_PER_MSEC); while (!set_isempty(pids)) { zero(status); r = waitid(P_ALL, 0, &status, WEXITED|WNOHANG); if (r < 0 && errno == EINTR) continue; if (r == 0 && status.si_pid > 0) { set_remove(pids, PID_TO_PTR(status.si_pid)); continue; } signum = sigtimedwait(&set, NULL, &ts); if (signum < 0) { if (errno != EAGAIN) log_error_errno(errno, "sigtimedwait() failed: %m"); break; } assert(signum == SIGCHLD); } /* * Kill hanging processes. */ SET_FOREACH(p, pids, i) { log_warning("Failed to terminate child %d, killing it", PTR_TO_PID(p)); (void) kill(PTR_TO_PID(p), SIGKILL); } } static int ask_on_consoles(int argc, char *argv[]) { _cleanup_set_free_ Set *pids = NULL; _cleanup_strv_free_ char **consoles = NULL; siginfo_t status = {}; char **tty; pid_t pid; int r; r = get_kernel_consoles(&consoles); if (r < 0) return log_error_errno(r, "Failed to determine devices of /dev/console: %m"); pids = set_new(NULL); if (!pids) return log_oom(); /* Start an agent on each console. */ STRV_FOREACH(tty, consoles) { r = ask_on_this_console(*tty, &pid, argc, argv); if (r < 0) return r; if (set_put(pids, PID_TO_PTR(pid)) < 0) return log_oom(); } /* Wait for an agent to exit. */ for (;;) { zero(status); if (waitid(P_ALL, 0, &status, WEXITED) < 0) { if (errno == EINTR) continue; return log_error_errno(errno, "waitid() failed: %m"); } set_remove(pids, PID_TO_PTR(status.si_pid)); break; } if (!is_clean_exit(status.si_code, status.si_status, EXIT_CLEAN_DAEMON, NULL)) log_error("Password agent failed with: %d", status.si_status); terminate_agents(pids); return 0; } int main(int argc, char *argv[]) { int r; log_set_target(LOG_TARGET_AUTO); log_parse_environment(); log_open(); umask(0022); r = parse_argv(argc, argv); if (r <= 0) goto finish; if (arg_console && !arg_device) /* * Spawn for each console device a separate process. */ r = ask_on_consoles(argc, argv); else { if (arg_device) { /* * Later on, a controlling terminal will be acquired, * therefore the current process has to become a session * leader and should not have a controlling terminal already. */ (void) setsid(); (void) release_terminal(); } if (IN_SET(arg_action, ACTION_WATCH, ACTION_WALL)) r = watch_passwords(); else r = show_passwords(); } finish: return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; }