/* SPDX-License-Identifier: LGPL-2.1-or-later */ /*** Copyright © 2015 Werner Fink ***/ #include #include #include #include #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "ask-password-api.h" #include "build.h" #include "conf-parser.h" #include "constants.h" #include "devnum-util.h" #include "dirent-util.h" #include "exit-status.h" #include "fd-util.h" #include "fileio.h" #include "hashmap.h" #include "inotify-util.h" #include "io-util.h" #include "macro.h" #include "main-func.h" #include "memory-util.h" #include "mkdir-label.h" #include "path-util.h" #include "pretty-print.h" #include "process-util.h" #include "set.h" #include "signal-util.h" #include "socket-util.h" #include "string-util.h" #include "strv.h" #include "terminal-util.h" #include "wall.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 send_passwords(const char *socket_name, char **passwords) { int r; assert(socket_name); union sockaddr_union sa; r = sockaddr_un_set_path(&sa.un, socket_name); if (r < 0) return r; socklen_t sa_len = r; size_t packet_length = 1; STRV_FOREACH(p, passwords) packet_length += strlen(*p) + 1; _cleanup_(erase_and_freep) char *packet = new(char, packet_length); if (!packet) return -ENOMEM; packet[0] = '+'; char *d = packet + 1; STRV_FOREACH(p, passwords) d = stpcpy(d, *p) + 1; _cleanup_close_ int socket_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0); if (socket_fd < 0) return log_debug_errno(errno, "socket(): %m"); ssize_t n = sendto(socket_fd, packet, packet_length, MSG_NOSIGNAL, &sa.sa, sa_len); if (n < 0) return log_debug_errno(errno, "sendto(): %m"); return (int) n; } static bool wall_tty_match(const char *path, bool is_local, void *userdata) { assert(path_is_absolute(path)); struct stat st; if (lstat(path, &st) < 0) { log_debug_errno(errno, "Failed to stat TTY '%s', not restricting wall: %m", path); return true; } if (!S_ISCHR(st.st_mode)) { log_debug("TTY '%s' is not a character device, not restricting wall.", 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. */ _cleanup_free_ char *p = NULL; if (asprintf(&p, "/run/systemd/ask-password-block/" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(st.st_rdev)) < 0) { log_oom_debug(); return true; } _cleanup_close_ int fd = open(p, O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY); if (fd < 0) { log_debug_errno(errno, "Failed to open the wall pipe for TTY '%s', not restricting wall: %m", path); return 1; } /* What, we managed to open the pipe? Then this tty is filtered. */ return 0; } static int agent_ask_password_tty( const char *message, usec_t until, AskPasswordFlags flags, const char *flag_file, char ***ret) { int tty_fd = -EBADF, r; const char *con = arg_device ?: "/dev/console"; if (arg_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); (void) terminal_reset_defensive_locked(tty_fd, /* switch_to_text= */ true); log_info("Starting password query on %s.", con); } AskPasswordRequest req = { .message = message, }; r = ask_password_tty(tty_fd, &req, until, flags, flag_file, ret); if (arg_console) { assert(tty_fd >= 0); tty_fd = safe_close(tty_fd); release_terminal(); if (r >= 0) log_info("Password query on %s finished successfully.", con); } return r; } static int process_one_password_file(const char *filename, FILE *f) { _cleanup_free_ char *socket_name = NULL, *message = NULL; bool accept_cached = false, echo = false, silent = false; uint64_t not_after = 0; pid_t pid = 0; const ConfigTableItem items[] = { { "Ask", "Socket", config_parse_string, CONFIG_PARSE_STRING_SAFE, &socket_name }, { "Ask", "NotAfter", config_parse_uint64, 0, ¬_after }, { "Ask", "Message", config_parse_string, 0, &message }, { "Ask", "PID", config_parse_pid, 0, &pid }, { "Ask", "AcceptCached", config_parse_bool, 0, &accept_cached }, { "Ask", "Echo", config_parse_bool, 0, &echo }, { "Ask", "Silent", config_parse_bool, 0, &silent }, {} }; int r; assert(filename); assert(f); r = config_parse(/* unit= */ NULL, filename, f, /* sections= */ "Ask\0", config_item_table_lookup, items, CONFIG_PARSE_RELAXED|CONFIG_PARSE_WARN, /* userdata= */ NULL, /* ret_stat= */ NULL); if (r < 0) return r; if (!socket_name) return log_error_errno(SYNTHETIC_ERRNO(EBADMSG), "Invalid password file %s", filename); if (not_after > 0 && now(CLOCK_MONOTONIC) > not_after) return 0; if (pid > 0 && pid_is_alive(pid) <= 0) return 0; switch (arg_action) { case ACTION_LIST: printf("'%s' (PID " PID_FMT ")\n", strna(message), pid); return 0; case ACTION_WALL: { _cleanup_free_ char *msg = NULL; if (asprintf(&msg, "Password entry required for \'%s\' (PID " PID_FMT ").\r\n" "Please enter password with the systemd-tty-ask-password-agent tool.", strna(message), pid) < 0) return log_oom(); (void) wall(msg, NULL, NULL, wall_tty_match, NULL); return 0; } case ACTION_QUERY: case ACTION_WATCH: { _cleanup_strv_free_erase_ char **passwords = NULL; AskPasswordFlags flags = 0; if (access(socket_name, W_OK) < 0) { if (arg_action == ACTION_QUERY) log_info("Not querying '%s' (PID " PID_FMT "), lacking privileges.", strna(message), pid); return 0; } SET_FLAG(flags, ASK_PASSWORD_ACCEPT_CACHED, accept_cached); SET_FLAG(flags, ASK_PASSWORD_CONSOLE_COLOR, arg_console); SET_FLAG(flags, ASK_PASSWORD_ECHO, echo); SET_FLAG(flags, ASK_PASSWORD_SILENT, silent); if (arg_plymouth) { AskPasswordRequest req = { .message = message, }; r = ask_password_plymouth(&req, not_after, flags, filename, &passwords); } else r = agent_ask_password_tty(message, not_after, flags, filename, &passwords); if (r < 0) { /* If the query went away, that's OK */ if (IN_SET(r, -ETIME, -ENOENT)) return 0; return log_error_errno(r, "Failed to query password: %m"); } assert(!strv_isempty(passwords)); r = send_passwords(socket_name, passwords); if (r < 0) return log_error_errno(r, "Failed to send: %m"); break; }} 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 int process_password_files(const char *path) { _cleanup_closedir_ DIR *d = NULL; int ret = 0, r; assert(path); d = opendir(path); if (!d) { if (errno == ENOENT) return 0; return log_error_errno(errno, "Failed to open '%s': %m", path); } FOREACH_DIRENT(de, d, return log_error_errno(errno, "Failed to read directory '%s': %m", path)) { _cleanup_free_ char *p = NULL; if (!IN_SET(de->d_type, DT_REG, DT_UNKNOWN)) continue; if (!startswith(de->d_name, "ask.")) continue; p = path_join(path, de->d_name); if (!p) return log_oom(); _cleanup_fclose_ FILE *f = NULL; r = xfopenat(dirfd(d), de->d_name, "re", O_NOFOLLOW, &f); if (r < 0) { log_warning_errno(r, "Failed to open '%s', ignoring: %m", p); continue; } RET_GATHER(ret, process_one_password_file(p, f)); } return ret; } static int process_and_watch_password_files(bool watch) { enum { FD_SIGNAL, FD_INOTIFY, _FD_MAX }; _cleanup_free_ char *user_ask_password_directory = NULL; _unused_ _cleanup_close_ int tty_block_fd = -EBADF; _cleanup_close_ int notify = -EBADF, signal_fd = -EBADF; 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); r = acquire_user_ask_password_directory(&user_ask_password_directory); if (r < 0) return log_error_errno(r, "Failed to determine per-user password directory: %m"); if (r > 0) (void) mkdir_p_label(user_ask_password_directory, 0755); assert_se(sigemptyset(&mask) >= 0); assert_se(sigset_add_many(&mask, SIGTERM) >= 0); assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) >= 0); if (watch) { 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_SIGNAL] = (struct pollfd) { .fd = signal_fd, .events = POLLIN }; notify = inotify_init1(IN_CLOEXEC); if (notify < 0) return log_error_errno(errno, "Failed to allocate directory watch: %m"); r = inotify_add_watch_and_warn(notify, "/run/systemd/ask-password", IN_CLOSE_WRITE|IN_MOVED_TO|IN_ONLYDIR); if (r < 0) return r; if (user_ask_password_directory) { r = inotify_add_watch_and_warn(notify, user_ask_password_directory, IN_CLOSE_WRITE|IN_MOVED_TO|IN_ONLYDIR); if (r < 0) return r; } pollfd[FD_INOTIFY] = (struct pollfd) { .fd = notify, .events = POLLIN }; } for (;;) { usec_t timeout = USEC_INFINITY; r = process_password_files("/run/systemd/ask-password"); if (user_ask_password_directory) RET_GATHER(r, process_password_files(user_ask_password_directory)); if (r == -ECANCELED) /* Disable poll() timeout since at least one password has been skipped and therefore * one file remains and is unlikely to trigger any events. */ timeout = 0; else if (r < 0) /* FIXME: we should do something here since otherwise the service * requesting the password won't notice the error and will wait * indefinitely. */ log_warning_errno(r, "Failed to process password, ignoring: %m"); if (!watch) break; r = ppoll_usec(pollfd, _FD_MAX, timeout); if (r == -EINTR) continue; if (r < 0) return r; if (pollfd[FD_INOTIFY].revents != 0) (void) flush_fd(notify); if (pollfd[FD_SIGNAL].revents != 0) break; } return 0; } static int help(void) { _cleanup_free_ char *link = NULL; int r; r = terminal_urlify_man("systemd-tty-ask-password-agent", "1", &link); if (r < 0) return log_oom(); printf("%s [OPTIONS...]\n\n" "%sProcess system password requests.%s\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[=DEVICE] Ask question on /dev/console (or DEVICE if specified)\n" " instead of the current TTY\n" "\nSee the %s for details.\n", program_invocation_short_name, ansi_highlight(), ansi_normal(), link); return 0; } 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': return help(); 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)) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Empty console device path is not allowed."); arg_device = optarg; } break; case '?': return -EINVAL; default: assert_not_reached(); } if (optind != argc) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "%s takes no arguments.", program_invocation_short_name); if (arg_plymouth || arg_console) { if (!IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH)) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Options --query and --watch conflict."); if (arg_plymouth && arg_console) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Options --plymouth and --console conflict."); } 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 an 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, char **arguments) { static const struct sigaction sigchld = { .sa_handler = nop_signal_handler, .sa_flags = SA_NOCLDSTOP | SA_RESTART, }; int r; assert_se(sigaction(SIGCHLD, &sigchld, NULL) >= 0); assert_se(sigaction(SIGHUP, &sigaction_default, NULL) >= 0); assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD) >= 0); r = safe_fork("(sd-passwd)", FORK_RESET_SIGNALS|FORK_LOG, ret_pid); if (r < 0) return r; if (r == 0) { assert_se(prctl(PR_SET_PDEATHSIG, SIGHUP) >= 0); STRV_FOREACH(i, arguments) { char *k; if (!streq(*i, "--console")) continue; k = strjoin("--console=", tty); if (!k) { log_oom(); _exit(EXIT_FAILURE); } free_and_replace(*i, k); } execv(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, arguments); _exit(EXIT_FAILURE); } return 0; } static void terminate_agents(Set *pids) { sigset_t set; void *p; int r, signum; /* * Request termination of the remaining processes as those * are not required anymore. */ SET_FOREACH(p, pids) (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); while (!set_isempty(pids)) { siginfo_t 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, TIMESPEC_STORE(50 * USEC_PER_MSEC)); if (signum < 0) { if (errno != EAGAIN) log_error_errno(errno, "sigtimedwait() failed: %m"); break; } assert(signum == SIGCHLD); } /* * Kill hanging processes. */ SET_FOREACH(p, pids) { 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(char *argv[]) { _cleanup_set_free_ Set *pids = NULL; _cleanup_strv_free_ char **consoles = NULL, **arguments = NULL; siginfo_t status = {}; 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(); arguments = strv_copy(argv); if (!arguments) return log_oom(); /* Start an agent on each console. */ STRV_FOREACH(tty, consoles) { r = ask_on_this_console(*tty, &pid, arguments); 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; } static int run(int argc, char *argv[]) { int r; log_setup(); umask(0022); r = parse_argv(argc, argv); if (r <= 0) return r; if (arg_console && !arg_device) /* * Spawn a separate process for each console device. */ return ask_on_consoles(argv); 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(); } return process_and_watch_password_files(!IN_SET(arg_action, ACTION_QUERY, ACTION_LIST)); } DEFINE_MAIN_FUNCTION(run);