src/tty-ask-password-agent.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdbool.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/socket.h>
  26 #include <sys/un.h>
  27 #include <stddef.h>
  28 #include <sys/poll.h>
  29 #include <sys/inotify.h>
  30 #include <unistd.h>
  31 #include <getopt.h>
  32 #include <sys/signalfd.h>
  33
  34 #include "util.h"
  35 #include "conf-parser.h"
  36 #include "utmp-wtmp.h"
  37 #include "socket-util.h"
  38 #include "ask-password-api.h"
  39
  40 static enum {
  41         ACTION_LIST,
  42         ACTION_QUERY,
  43         ACTION_WATCH,
  44         ACTION_WALL
  45 } arg_action = ACTION_QUERY;
  46
  47 static bool arg_plymouth = false;
  48
  49 static int ask_password_plymouth(const char *message, usec_t until, const char *flag_file, char **_passphrase) {
  50         int fd = -1, notify = -1;
  51         union sockaddr_union sa;
  52         char *packet = NULL;
  53         ssize_t k;
  54         int r, n;
  55         struct pollfd pollfd[2];
  56         char buffer[LINE_MAX];
  57         size_t p = 0;
  58         enum {
  59                 POLL_SOCKET,
  60                 POLL_INOTIFY
  61         };
  62
  63         if (flag_file) {
  64                 if ((notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
  65                         r = -errno;
  66                         goto finish;
  67                 }
  68
  69                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0) {
  70                         r = -errno;
  71                         goto finish;
  72                 }
  73         }
  74
  75         if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0)) < 0) {
  76                 r = -errno;
  77                 goto finish;
  78         }
  79
  80         zero(sa);
  81         sa.sa.sa_family = AF_UNIX;
  82         strncpy(sa.un.sun_path+1, "/ply-boot-protocol", sizeof(sa.un.sun_path)-1);
  83
  84         if (connect(fd, &sa.sa, sizeof(sa.un)) < 0) {
  85                 r = -errno;
  86                 goto finish;
  87         }
  88
  89         if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
  90                 r = -ENOMEM;
  91                 goto finish;
  92         }
  93
  94         if ((k = loop_write(fd, packet, n+1, true)) != n+1) {
  95                 r = k < 0 ? (int) k : -EIO;
  96                 goto finish;
  97         }
  98
  99         zero(pollfd);
 100         pollfd[POLL_SOCKET].fd = fd;
 101         pollfd[POLL_SOCKET].events = POLLIN;
 102         pollfd[POLL_INOTIFY].fd = notify;
 103         pollfd[POLL_INOTIFY].events = POLLIN;
 104
 105         for (;;) {
 106                 int sleep_for = -1, j;
 107
 108                 if (until > 0) {
 109                         usec_t y;
 110
 111                         y = now(CLOCK_MONOTONIC);
 112
 113                         if (y > until) {
 114                                 r = -ETIMEDOUT;
 115                                 goto finish;
 116                         }
 117
 118                         sleep_for = (int) ((until - y) / USEC_PER_MSEC);
 119                 }
 120
 121                 if (flag_file)
 122                         if (access(flag_file, F_OK) < 0) {
 123                                 r = -errno;
 124                                 goto finish;
 125                         }
 126
 127                 if ((j = poll(pollfd, notify > 0 ? 2 : 1, sleep_for)) < 0) {
 128
 129                         if (errno == EINTR)
 130                                 continue;
 131
 132                         r = -errno;
 133                         goto finish;
 134                 } else if (j == 0) {
 135                         r = -ETIMEDOUT;
 136                         goto finish;
 137                 }
 138
 139                 if (notify > 0 && pollfd[POLL_INOTIFY].revents != 0)
 140                         flush_fd(notify);
 141
 142                 if (pollfd[POLL_SOCKET].revents == 0)
 143                         continue;
 144
 145                 if ((k = read(fd, buffer + p, sizeof(buffer) - p)) <= 0) {
 146                         r = k < 0 ? -errno : -EIO;
 147                         goto finish;
 148                 }
 149
 150                 p += k;
 151
 152                 if (p < 1)
 153                         continue;
 154
 155                 if (buffer[0] == 5) {
 156                         /* No password, because UI not shown */
 157                         r = -ENOENT;
 158                         goto finish;
 159
 160                 } else if (buffer[0] == 2) {
 161                         uint32_t size;
 162                         char *s;
 163
 164                         /* One answer */
 165                         if (p < 5)
 166                                 continue;
 167
 168                         memcpy(&size, buffer+1, sizeof(size));
 169                         if (size+5 > sizeof(buffer)) {
 170                                 r = -EIO;
 171                                 goto finish;
 172                         }
 173
 174                         if (p-5 < size)
 175                                 continue;
 176
 177                         if (!(s = strndup(buffer + 5, size))) {
 178                                 r = -ENOMEM;
 179                                 goto finish;
 180                         }
 181
 182                         *_passphrase = s;
 183                         break;
 184                 } else {
 185                         /* Unknown packet */
 186                         r = -EIO;
 187                         goto finish;
 188                 }
 189         }
 190
 191         r = 0;
 192
 193 finish:
 194         if (notify >= 0)
 195                 close_nointr_nofail(notify);
 196
 197         if (fd >= 0)
 198                 close_nointr_nofail(fd);
 199
 200         free(packet);
 201
 202         return r;
 203 }
 204
 205 static int parse_password(const char *filename, char **wall) {
 206         char *socket_name = NULL, *message = NULL, *packet = NULL;
 207         uint64_t not_after = 0;
 208         unsigned pid = 0;
 209         int socket_fd = -1;
 210
 211         const ConfigItem items[] = {
 212                 { "Socket",   config_parse_string,   &socket_name, "Ask" },
 213                 { "NotAfter", config_parse_uint64,   &not_after,   "Ask" },
 214                 { "Message",  config_parse_string,   &message,     "Ask" },
 215                 { "PID",      config_parse_unsigned, &pid,         "Ask" },
 216         };
 217
 218         FILE *f;
 219         int r;
 220         usec_t n;
 221
 222         assert(filename);
 223
 224         if (!(f = fopen(filename, "re"))) {
 225
 226                 if (errno == ENOENT)
 227                         return 0;
 228
 229                 log_error("open(%s): %m", filename);
 230                 return -errno;
 231         }
 232
 233         if ((r = config_parse(filename, f, NULL, items, false, NULL)) < 0) {
 234                 log_error("Failed to parse password file %s: %s", filename, strerror(-r));
 235                 goto finish;
 236         }
 237
 238         if (!socket_name || not_after <= 0) {
 239                 log_error("Invalid password file %s", filename);
 240                 r = -EBADMSG;
 241                 goto finish;
 242         }
 243
 244         n = now(CLOCK_MONOTONIC);
 245         if (n > not_after) {
 246                 r = 0;
 247                 goto finish;
 248         }
 249
 250         if (arg_action == ACTION_LIST)
 251                 printf("'%s' (PID %u)\n", message, pid);
 252         else if (arg_action == ACTION_WALL) {
 253                 char *_wall;
 254
 255                 if (asprintf(&_wall,
 256                              "%s%sPassword entry required for \'%s\' (PID %u).\r\n"
 257                              "Please enter password with the systemd-tty-password-agent tool!",
 258                              *wall ? *wall : "",
 259                              *wall ? "\r\n\r\n" : "",
 260                              message,
 261                              pid) < 0) {
 262                         log_error("Out of memory");
 263                         r = -ENOMEM;
 264                         goto finish;
 265                 }
 266
 267                 free(*wall);
 268                 *wall = _wall;
 269         } else {
 270                 union {
 271                         struct sockaddr sa;
 272                         struct sockaddr_un un;
 273                 } sa;
 274                 char *password;
 275
 276                 assert(arg_action == ACTION_QUERY ||
 277                        arg_action == ACTION_WATCH);
 278
 279                 if (access(socket_name, W_OK) < 0) {
 280
 281                         if (arg_action == ACTION_QUERY)
 282                                 log_info("Not querying '%s' (PID %u), lacking privileges.", message, pid);
 283
 284                         r = 0;
 285                         goto finish;
 286                 }
 287
 288                 if (arg_plymouth)
 289                         r = ask_password_plymouth(message, not_after, filename, &password);
 290                 else
 291                         r = ask_password_tty(message, not_after, filename, &password);
 292
 293                 if (r < 0) {
 294                         log_error("Failed to query password: %s", strerror(-r));
 295                         goto finish;
 296                 }
 297
 298                 asprintf(&packet, "+%s", password);
 299                 free(password);
 300
 301                 if (!packet) {
 302                         log_error("Out of memory");
 303                         r = -ENOMEM;
 304                         goto finish;
 305                 }
 306
 307                 if ((socket_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
 308                         log_error("socket(): %m");
 309                         r = -errno;
 310                         goto finish;
 311                 }
 312
 313                 zero(sa);
 314                 sa.un.sun_family = AF_UNIX;
 315                 strncpy(sa.un.sun_path, socket_name, sizeof(sa.un.sun_path));
 316
 317                 if (sendto(socket_fd, packet, strlen(packet), MSG_NOSIGNAL, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(socket_name)) < 0) {
 318                         log_error("Failed to send: %m");
 319                         r = -errno;
 320                         goto finish;
 321                 }
 322         }
 323
 324 finish:
 325         fclose(f);
 326
 327         if (socket_fd >= 0)
 328                 close_nointr_nofail(socket_fd);
 329
 330         free(packet);
 331         free(socket_name);
 332         free(message);
 333
 334         return r;
 335 }
 336
 337 static int show_passwords(void) {
 338         DIR *d;
 339         struct dirent *de;
 340         int r = 0;
 341
 342         if (!(d = opendir("/dev/.systemd/ask-password"))) {
 343                 if (errno == ENOENT)
 344                         return 0;
 345
 346                 log_error("opendir(): %m");
 347                 return -errno;
 348         }
 349
 350         while ((de = readdir(d))) {
 351                 char *p;
 352                 int q;
 353                 char *wall;
 354
 355                 if (de->d_type != DT_REG)
 356                         continue;
 357
 358                 if (ignore_file(de->d_name))
 359                         continue;
 360
 361                 if (!startswith(de->d_name, "ask."))
 362                         continue;
 363
 364                 if (!(p = strappend("/dev/.systemd/ask-password/", de->d_name))) {
 365                         log_error("Out of memory");
 366                         r = -ENOMEM;
 367                         goto finish;
 368                 }
 369
 370                 wall = NULL;
 371                 if ((q = parse_password(p, &wall)) < 0)
 372                         r = q;
 373
 374                 free(p);
 375
 376                 if (wall) {
 377                         utmp_wall(wall);
 378                         free(wall);
 379                 }
 380         }
 381
 382 finish:
 383         if (d)
 384                 closedir(d);
 385
 386         return r;
 387 }
 388
 389 static int watch_passwords(void) {
 390         enum {
 391                 FD_INOTIFY,
 392                 FD_SIGNAL,
 393                 _FD_MAX
 394         };
 395
 396         int notify = -1, signal_fd = -1;
 397         struct pollfd pollfd[_FD_MAX];
 398         sigset_t mask;
 399         int r;
 400
 401         mkdir_p("/dev/.systemd/ask-password", 0755);
 402
 403         if ((notify = inotify_init1(IN_CLOEXEC)) < 0) {
 404                 r = -errno;
 405                 goto finish;
 406         }
 407
 408         if (inotify_add_watch(notify, "/dev/.systemd/ask-password", IN_CLOSE_WRITE|IN_MOVED_TO) < 0) {
 409                 r = -errno;
 410                 goto finish;
 411         }
 412
 413         assert_se(sigemptyset(&mask) == 0);
 414         sigset_add_many(&mask, SIGINT, SIGTERM, -1);
 415         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
 416
 417         if ((signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) {
 418                 log_error("signalfd(): %m");
 419                 r = -errno;
 420                 goto finish;
 421         }
 422
 423         zero(pollfd);
 424         pollfd[FD_INOTIFY].fd = notify;
 425         pollfd[FD_INOTIFY].events = POLLIN;
 426         pollfd[FD_SIGNAL].fd = signal_fd;
 427         pollfd[FD_SIGNAL].events = POLLIN;
 428
 429         for (;;) {
 430                 if ((r = show_passwords()) < 0)
 431                         break;
 432
 433                 if (poll(pollfd, _FD_MAX, -1) < 0) {
 434
 435                         if (errno == EINTR)
 436                                 continue;
 437
 438                         r = -errno;
 439                         goto finish;
 440                 }
 441
 442                 if (pollfd[FD_INOTIFY].revents != 0)
 443                         flush_fd(notify);
 444
 445                 if (pollfd[FD_SIGNAL].revents != 0)
 446                         break;
 447         }
 448
 449         r = 0;
 450
 451 finish:
 452         if (notify >= 0)
 453                 close_nointr_nofail(notify);
 454
 455         if (signal_fd >= 0)
 456                 close_nointr_nofail(signal_fd);
 457
 458         return r;
 459 }
 460
 461 static int help(void) {
 462
 463         printf("%s [OPTIONS...]\n\n"
 464                "Process system password requests.\n\n"
 465                "  -h --help     Show this help\n"
 466                "     --list     Show pending password requests\n"
 467                "     --query    Process pending password requests\n"
 468                "     --watch    Continously process password requests\n"
 469                "     --wall     Continously forward password requests to wall\n"
 470                "     --plymouth Ask question with Plymouth instead of on TTY\n",
 471                program_invocation_short_name);
 472
 473         return 0;
 474 }
 475
 476 static int parse_argv(int argc, char *argv[]) {
 477
 478         enum {
 479                 ARG_LIST = 0x100,
 480                 ARG_QUERY,
 481                 ARG_WATCH,
 482                 ARG_WALL,
 483                 ARG_PLYMOUTH
 484         };
 485
 486         static const struct option options[] = {
 487                 { "help",     no_argument, NULL, 'h'          },
 488                 { "list",     no_argument, NULL, ARG_LIST     },
 489                 { "query",    no_argument, NULL, ARG_QUERY    },
 490                 { "watch",    no_argument, NULL, ARG_WATCH    },
 491                 { "wall",     no_argument, NULL, ARG_WALL     },
 492                 { "plymouth", no_argument, NULL, ARG_PLYMOUTH },
 493                 { NULL,    0,           NULL, 0               }
 494         };
 495
 496         int c;
 497
 498         assert(argc >= 0);
 499         assert(argv);
 500
 501         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
 502
 503                 switch (c) {
 504
 505                 case 'h':
 506                         help();
 507                         return 0;
 508
 509                 case ARG_LIST:
 510                         arg_action = ACTION_LIST;
 511                         break;
 512
 513                 case ARG_QUERY:
 514                         arg_action = ACTION_QUERY;
 515                         break;
 516
 517                 case ARG_WATCH:
 518                         arg_action = ACTION_WATCH;
 519                         break;
 520
 521                 case ARG_WALL:
 522                         arg_action = ACTION_WALL;
 523                         break;
 524
 525                 case ARG_PLYMOUTH:
 526                         arg_plymouth = true;
 527                         break;
 528
 529                 case '?':
 530                         return -EINVAL;
 531
 532                 default:
 533                         log_error("Unknown option code %c", c);
 534                         return -EINVAL;
 535                 }
 536         }
 537
 538         if (optind != argc) {
 539                 help();
 540                 return -EINVAL;
 541         }
 542
 543         return 1;
 544 }
 545
 546 int main(int argc, char *argv[]) {
 547         int r;
 548
 549         log_parse_environment();
 550         log_open();
 551
 552         if ((r = parse_argv(argc, argv)) <= 0)
 553                 goto finish;
 554
 555         if (arg_action == ACTION_WATCH ||
 556             arg_action == ACTION_WALL)
 557                 r = watch_passwords();
 558         else
 559                 r = show_passwords();
 560
 561 finish:
 562         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 563 }