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