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Diffstat (limited to 'src/tty-ask-password-agent/tty-ask-password-agent.c')
-rw-r--r--src/tty-ask-password-agent/tty-ask-password-agent.c709
1 files changed, 709 insertions, 0 deletions
diff --git a/src/tty-ask-password-agent/tty-ask-password-agent.c b/src/tty-ask-password-agent/tty-ask-password-agent.c
new file mode 100644
index 0000000..b7d279c
--- /dev/null
+++ b/src/tty-ask-password-agent/tty-ask-password-agent.c
@@ -0,0 +1,709 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+ Copyright © 2015 Werner Fink
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <sys/prctl.h>
+#include <sys/signalfd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#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 "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 "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 send_passwords(const char *socket_name, char **passwords) {
+ _cleanup_(erase_and_freep) char *packet = NULL;
+ _cleanup_close_ int socket_fd = -1;
+ union sockaddr_union sa;
+ socklen_t sa_len;
+ size_t packet_length = 1;
+ char *d;
+ ssize_t n;
+ int r;
+
+ assert(socket_name);
+
+ r = sockaddr_un_set_path(&sa.un, socket_name);
+ if (r < 0)
+ return r;
+ sa_len = r;
+
+ 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)
+ return log_debug_errno(errno, "socket(): %m");
+
+ 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) {
+ _cleanup_free_ char *p = NULL;
+ _cleanup_close_ int fd = -1;
+ struct stat st;
+
+ assert(path_is_absolute(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 agent_ask_password_tty(
+ const char *message,
+ usec_t until,
+ AskPasswordFlags flags,
+ const char *flag_file,
+ char ***ret) {
+
+ int tty_fd = -1, 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);
+
+ r = reset_terminal_fd(tty_fd, true);
+ if (r < 0)
+ log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
+
+ log_info("Starting password query on %s.", con);
+ }
+
+ r = ask_password_tty(tty_fd, message, NULL, until, flags, flag_file, ret);
+
+ if (arg_console) {
+ 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) {
+ _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, &not_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);
+
+ r = config_parse(NULL, filename, NULL,
+ NULL,
+ config_item_table_lookup, items,
+ CONFIG_PARSE_RELAXED|CONFIG_PARSE_WARN,
+ NULL,
+ 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))
+ 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 *wall = NULL;
+
+ if (asprintf(&wall,
+ "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) utmp_wall(wall, 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)
+ r = ask_password_plymouth(message, 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");
+ }
+
+ if (strv_isempty(passwords))
+ return -ECANCELED;
+
+ 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(void) {
+ _cleanup_closedir_ DIR *d = NULL;
+ 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(de, d, return log_error_errno(errno, "Failed to read directory: %m")) {
+ _cleanup_free_ char *p = NULL;
+ int q;
+
+ /* We only support /run on tmpfs, hence we can rely on
+ * d_type to be reliable */
+
+ if (de->d_type != DT_REG)
+ continue;
+
+ if (!startswith(de->d_name, "ask."))
+ continue;
+
+ p = path_join("/run/systemd/ask-password", de->d_name);
+ if (!p)
+ return log_oom();
+
+ q = process_one_password_file(p);
+ if (q < 0 && r == 0)
+ r = q;
+ }
+
+ return r;
+}
+
+static int process_and_watch_password_files(bool watch) {
+ enum {
+ FD_SIGNAL,
+ FD_INOTIFY,
+ _FD_MAX
+ };
+
+ _unused_ _cleanup_close_ int tty_block_fd = -1;
+ _cleanup_close_ int notify = -1, signal_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);
+
+ assert_se(sigemptyset(&mask) >= 0);
+ assert_se(sigset_add_many(&mask, SIGTERM, -1) >= 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);
+ if (r < 0)
+ return r;
+
+ pollfd[FD_INOTIFY] = (struct pollfd) { .fd = notify, .events = POLLIN };
+ }
+
+ for (;;) {
+ usec_t timeout = USEC_INFINITY;
+
+ r = process_password_files();
+ if (r < 0) {
+ 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
+ /* FIXME: we should do something here since otherwise the service
+ * requesting the password won't notice the error and will wait
+ * indefinitely. */
+ log_error_errno(r, "Failed to process password: %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,
+ };
+ static const struct sigaction sighup = {
+ .sa_handler = SIG_DFL,
+ .sa_flags = SA_RESTART,
+ };
+ int r;
+
+ assert_se(sigaction(SIGCHLD, &sigchld, NULL) >= 0);
+ assert_se(sigaction(SIGHUP, &sighup, NULL) >= 0);
+ assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD, -1) >= 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-04 00:36:37 +0000