src/shared/ask-password-api.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <inttypes.h>
   6 #include <limits.h>
   7 #include <poll.h>
   8 #include <signal.h>
   9 #include <stdbool.h>
  10 #include <stddef.h>
  11 #include <stdint.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/inotify.h>
  16 #include <sys/signalfd.h>
  17 #include <sys/socket.h>
  18 #include <sys/stat.h>
  19 #include <sys/time.h>
  20 #include <sys/uio.h>
  21 #include <sys/un.h>
  22 #include <termios.h>
  23 #include <unistd.h>
  24
  25 #include "alloc-util.h"
  26 #include "ask-password-api.h"
  27 #include "fd-util.h"
  28 #include "fileio.h"
  29 #include "format-util.h"
  30 #include "fs-util.h"
  31 #include "io-util.h"
  32 #include "log.h"
  33 #include "macro.h"
  34 #include "missing.h"
  35 #include "mkdir.h"
  36 #include "process-util.h"
  37 #include "random-util.h"
  38 #include "signal-util.h"
  39 #include "socket-util.h"
  40 #include "string-util.h"
  41 #include "strv.h"
  42 #include "terminal-util.h"
  43 #include "time-util.h"
  44 #include "umask-util.h"
  45 #include "utf8.h"
  46 #include "util.h"
  47
  48 #define KEYRING_TIMEOUT_USEC ((5 * USEC_PER_MINUTE) / 2)
  49
  50 static int lookup_key(const char *keyname, key_serial_t *ret) {
  51         key_serial_t serial;
  52
  53         assert(keyname);
  54         assert(ret);
  55
  56         serial = request_key("user", keyname, NULL, 0);
  57         if (serial == -1)
  58                 return negative_errno();
  59
  60         *ret = serial;
  61         return 0;
  62 }
  63
  64 static int retrieve_key(key_serial_t serial, char ***ret) {
  65         _cleanup_free_ char *p = NULL;
  66         long m = 100, n;
  67         char **l;
  68
  69         assert(ret);
  70
  71         for (;;) {
  72                 p = new(char, m);
  73                 if (!p)
  74                         return -ENOMEM;
  75
  76                 n = keyctl(KEYCTL_READ, (unsigned long) serial, (unsigned long) p, (unsigned long) m, 0);
  77                 if (n < 0)
  78                         return -errno;
  79
  80                 if (n < m)
  81                         break;
  82
  83                 explicit_bzero_safe(p, n);
  84                 free(p);
  85                 m *= 2;
  86         }
  87
  88         l = strv_parse_nulstr(p, n);
  89         if (!l)
  90                 return -ENOMEM;
  91
  92         explicit_bzero_safe(p, n);
  93
  94         *ret = l;
  95         return 0;
  96 }
  97
  98 static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
  99         _cleanup_strv_free_erase_ char **l = NULL;
 100         _cleanup_free_ char *p = NULL;
 101         key_serial_t serial;
 102         size_t n;
 103         int r;
 104
 105         assert(keyname);
 106         assert(passwords);
 107
 108         if (!(flags & ASK_PASSWORD_PUSH_CACHE))
 109                 return 0;
 110
 111         r = lookup_key(keyname, &serial);
 112         if (r >= 0) {
 113                 r = retrieve_key(serial, &l);
 114                 if (r < 0)
 115                         return r;
 116         } else if (r != -ENOKEY)
 117                 return r;
 118
 119         r = strv_extend_strv(&l, passwords, true);
 120         if (r <= 0)
 121                 return r;
 122
 123         r = strv_make_nulstr(l, &p, &n);
 124         if (r < 0)
 125                 return r;
 126
 127         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 128         explicit_bzero_safe(p, n);
 129         if (serial == -1)
 130                 return -errno;
 131
 132         if (keyctl(KEYCTL_SET_TIMEOUT,
 133                    (unsigned long) serial,
 134                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 135                 log_debug_errno(errno, "Failed to adjust timeout: %m");
 136
 137         /* Tell everyone to check the keyring */
 138         (void) touch("/run/systemd/ask-password");
 139
 140         log_debug("Added key to keyring as %" PRIi32 ".", serial);
 141
 142         return 1;
 143 }
 144
 145 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 146         int r;
 147
 148         assert(keyname);
 149         assert(passwords);
 150
 151         r = add_to_keyring(keyname, flags, passwords);
 152         if (r < 0)
 153                 return log_debug_errno(r, "Failed to add password to keyring: %m");
 154
 155         return 0;
 156 }
 157
 158 int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
 159
 160         key_serial_t serial;
 161         int r;
 162
 163         assert(keyname);
 164         assert(ret);
 165
 166         if (!(flags & ASK_PASSWORD_ACCEPT_CACHED))
 167                 return -EUNATCH;
 168
 169         r = lookup_key(keyname, &serial);
 170         if (r == -ENOSYS) /* when retrieving the distinction doesn't matter */
 171                 return -ENOKEY;
 172         if (r < 0)
 173                 return r;
 174
 175         return retrieve_key(serial, ret);
 176 }
 177
 178 static void backspace_chars(int ttyfd, size_t p) {
 179
 180         if (ttyfd < 0)
 181                 return;
 182
 183         while (p > 0) {
 184                 p--;
 185
 186                 loop_write(ttyfd, "\b \b", 3, false);
 187         }
 188 }
 189
 190 static void backspace_string(int ttyfd, const char *str) {
 191         size_t m;
 192
 193         assert(str);
 194
 195         if (ttyfd < 0)
 196                 return;
 197
 198         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 199
 200         m = utf8_n_codepoints(str);
 201         if (m == (size_t) -1)
 202                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes output. Most
 203                                   * likely this happened because we are not in an UTF-8 locale, and in that case that
 204                                   * is the correct thing to do. And even if it's not, terminals tend to stop
 205                                   * backspacing at the leftmost column, hence backspacing too much should be mostly
 206                                   * OK. */
 207
 208         backspace_chars(ttyfd, m);
 209 }
 210
 211 int ask_password_tty(
 212                 int ttyfd,
 213                 const char *message,
 214                 const char *keyname,
 215                 usec_t until,
 216                 AskPasswordFlags flags,
 217                 const char *flag_file,
 218                 char ***ret) {
 219
 220         enum {
 221                 POLL_TTY,
 222                 POLL_INOTIFY,
 223                 _POLL_MAX,
 224         };
 225
 226         bool reset_tty = false, dirty = false, use_color = false;
 227         _cleanup_close_ int cttyfd = -1, notify = -1;
 228         struct termios old_termios, new_termios;
 229         char passphrase[LINE_MAX + 1] = {}, *x;
 230         _cleanup_strv_free_erase_ char **l = NULL;
 231         struct pollfd pollfd[_POLL_MAX];
 232         size_t p = 0, codepoint = 0;
 233         int r;
 234
 235         assert(ret);
 236
 237         if (flags & ASK_PASSWORD_NO_TTY)
 238                 return -EUNATCH;
 239
 240         if (!message)
 241                 message = "Password:";
 242
 243         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 244                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 245                 if (notify < 0)
 246                         return -errno;
 247         }
 248         if (flag_file) {
 249                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 250                         return -errno;
 251         }
 252         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 253                 r = ask_password_keyring(keyname, flags, ret);
 254                 if (r >= 0)
 255                         return 0;
 256                 else if (r != -ENOKEY)
 257                         return r;
 258
 259                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 260                         return -errno;
 261         }
 262
 263         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 264         if (ttyfd < 0)
 265                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 266
 267         if (ttyfd >= 0) {
 268                 if (tcgetattr(ttyfd, &old_termios) < 0)
 269                         return -errno;
 270
 271                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 272                         use_color = dev_console_colors_enabled();
 273                 else
 274                         use_color = colors_enabled();
 275
 276                 if (use_color)
 277                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 278
 279                 (void) loop_write(ttyfd, message, strlen(message), false);
 280                 (void) loop_write(ttyfd, " ", 1, false);
 281
 282                 if (use_color)
 283                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 284
 285                 new_termios = old_termios;
 286                 new_termios.c_lflag &= ~(ICANON|ECHO);
 287                 new_termios.c_cc[VMIN] = 1;
 288                 new_termios.c_cc[VTIME] = 0;
 289
 290                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 291                         r = -errno;
 292                         goto finish;
 293                 }
 294
 295                 reset_tty = true;
 296         }
 297
 298         pollfd[POLL_TTY] = (struct pollfd) {
 299                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 300                 .events = POLLIN,
 301         };
 302         pollfd[POLL_INOTIFY] = (struct pollfd) {
 303                 .fd = notify,
 304                 .events = POLLIN,
 305         };
 306
 307         for (;;) {
 308                 int sleep_for = -1, k;
 309                 ssize_t n;
 310                 char c;
 311
 312                 if (until > 0) {
 313                         usec_t y;
 314
 315                         y = now(CLOCK_MONOTONIC);
 316
 317                         if (y > until) {
 318                                 r = -ETIME;
 319                                 goto finish;
 320                         }
 321
 322                         sleep_for = (int) DIV_ROUND_UP(until - y, USEC_PER_MSEC);
 323                 }
 324
 325                 if (flag_file)
 326                         if (access(flag_file, F_OK) < 0) {
 327                                 r = -errno;
 328                                 goto finish;
 329                         }
 330
 331                 k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 332                 if (k < 0) {
 333                         if (errno == EINTR)
 334                                 continue;
 335
 336                         r = -errno;
 337                         goto finish;
 338                 } else if (k == 0) {
 339                         r = -ETIME;
 340                         goto finish;
 341                 }
 342
 343                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0) {
 344                         (void) flush_fd(notify);
 345
 346                         r = ask_password_keyring(keyname, flags, ret);
 347                         if (r >= 0) {
 348                                 r = 0;
 349                                 goto finish;
 350                         } else if (r != -ENOKEY)
 351                                 goto finish;
 352                 }
 353
 354                 if (pollfd[POLL_TTY].revents == 0)
 355                         continue;
 356
 357                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 358                 if (n < 0) {
 359                         if (IN_SET(errno, EINTR, EAGAIN))
 360                                 continue;
 361
 362                         r = -errno;
 363                         goto finish;
 364
 365                 }
 366
 367                 /* We treat EOF, newline and NUL byte all as valid end markers */
 368                 if (n == 0 || c == '\n' || c == 0)
 369                         break;
 370
 371                 if (c == 21) { /* C-u */
 372
 373                         if (!(flags & ASK_PASSWORD_SILENT))
 374                                 backspace_string(ttyfd, passphrase);
 375
 376                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 377                         p = codepoint = 0;
 378
 379                 } else if (IN_SET(c, '\b', 127)) {
 380
 381                         if (p > 0) {
 382                                 size_t q;
 383
 384                                 if (!(flags & ASK_PASSWORD_SILENT))
 385                                         backspace_chars(ttyfd, 1);
 386
 387                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the last one
 388                                  * begins */
 389                                 q = 0;
 390                                 for (;;) {
 391                                         size_t z;
 392
 393                                         z = utf8_encoded_valid_unichar(passphrase + q);
 394                                         if (z == 0) {
 395                                                 q = (size_t) -1; /* Invalid UTF8! */
 396                                                 break;
 397                                         }
 398
 399                                         if (q + z >= p) /* This one brings us over the edge */
 400                                                 break;
 401
 402                                         q += z;
 403                                 }
 404
 405                                 p = codepoint = q == (size_t) -1 ? p - 1 : q;
 406                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 407
 408                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 409
 410                                 flags |= ASK_PASSWORD_SILENT;
 411
 412                                 /* There are two ways to enter silent mode. Either by pressing backspace as first key
 413                                  * (and only as first key), or ... */
 414
 415                                 if (ttyfd >= 0)
 416                                         (void) loop_write(ttyfd, "(no echo) ", 10, false);
 417
 418                         } else if (ttyfd >= 0)
 419                                 (void) loop_write(ttyfd, "\a", 1, false);
 420
 421                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 422
 423                         backspace_string(ttyfd, passphrase);
 424                         flags |= ASK_PASSWORD_SILENT;
 425
 426                         /* ... or by pressing TAB at any time. */
 427
 428                         if (ttyfd >= 0)
 429                                 (void) loop_write(ttyfd, "(no echo) ", 10, false);
 430
 431                 } else if (p >= sizeof(passphrase)-1) {
 432
 433                         /* Reached the size limit */
 434                         if (ttyfd >= 0)
 435                                 (void) loop_write(ttyfd, "\a", 1, false);
 436
 437                 } else {
 438                         passphrase[p++] = c;
 439
 440                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 441                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 442                                 n = utf8_encoded_valid_unichar(passphrase + codepoint);
 443                                 if (n >= 0) {
 444                                         codepoint = p;
 445                                         (void) loop_write(ttyfd, (flags & ASK_PASSWORD_ECHO) ? &c : "*", 1, false);
 446                                 }
 447                         }
 448
 449                         dirty = true;
 450                 }
 451
 452                 /* Let's forget this char, just to not keep needlessly copies of key material around */
 453                 c = 'x';
 454         }
 455
 456         x = strndup(passphrase, p);
 457         explicit_bzero_safe(passphrase, sizeof(passphrase));
 458         if (!x) {
 459                 r = -ENOMEM;
 460                 goto finish;
 461         }
 462
 463         r = strv_consume(&l, x);
 464         if (r < 0)
 465                 goto finish;
 466
 467         if (keyname)
 468                 (void) add_to_keyring_and_log(keyname, flags, l);
 469
 470         *ret = TAKE_PTR(l);
 471         r = 0;
 472
 473 finish:
 474         if (ttyfd >= 0 && reset_tty) {
 475                 (void) loop_write(ttyfd, "\n", 1, false);
 476                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 477         }
 478
 479         return r;
 480 }
 481
 482 static int create_socket(char **ret) {
 483         _cleanup_free_ char *path = NULL;
 484         union sockaddr_union sa = {};
 485         _cleanup_close_ int fd = -1;
 486         int salen, r;
 487
 488         assert(ret);
 489
 490         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 491         if (fd < 0)
 492                 return -errno;
 493
 494         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 495                 return -ENOMEM;
 496
 497         salen = sockaddr_un_set_path(&sa.un, path);
 498         if (salen < 0)
 499                 return salen;
 500
 501         RUN_WITH_UMASK(0177) {
 502                 if (bind(fd, &sa.sa, salen) < 0)
 503                         return -errno;
 504         }
 505
 506         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 507         if (r < 0)
 508                 return r;
 509
 510         *ret = TAKE_PTR(path);
 511         return TAKE_FD(fd);
 512 }
 513
 514 int ask_password_agent(
 515                 const char *message,
 516                 const char *icon,
 517                 const char *id,
 518                 const char *keyname,
 519                 usec_t until,
 520                 AskPasswordFlags flags,
 521                 char ***ret) {
 522
 523         enum {
 524                 FD_SOCKET,
 525                 FD_SIGNAL,
 526                 FD_INOTIFY,
 527                 _FD_MAX
 528         };
 529
 530         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 531         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 532         char final[sizeof(temp)] = "";
 533         _cleanup_free_ char *socket_name = NULL;
 534         _cleanup_strv_free_erase_ char **l = NULL;
 535         _cleanup_fclose_ FILE *f = NULL;
 536         struct pollfd pollfd[_FD_MAX];
 537         sigset_t mask, oldmask;
 538         int r;
 539
 540         assert(ret);
 541
 542         if (flags & ASK_PASSWORD_NO_AGENT)
 543                 return -EUNATCH;
 544
 545         assert_se(sigemptyset(&mask) >= 0);
 546         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 547         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 548
 549         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 550
 551         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 552                 r = ask_password_keyring(keyname, flags, ret);
 553                 if (r >= 0) {
 554                         r = 0;
 555                         goto finish;
 556                 } else if (r != -ENOKEY)
 557                         goto finish;
 558
 559                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 560                 if (notify < 0) {
 561                         r = -errno;
 562                         goto finish;
 563                 }
 564                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 565                         r = -errno;
 566                         goto finish;
 567                 }
 568         }
 569
 570         fd = mkostemp_safe(temp);
 571         if (fd < 0) {
 572                 r = fd;
 573                 goto finish;
 574         }
 575
 576         (void) fchmod(fd, 0644);
 577
 578         f = fdopen(fd, "w");
 579         if (!f) {
 580                 r = -errno;
 581                 goto finish;
 582         }
 583
 584         fd = -1;
 585
 586         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 587         if (signal_fd < 0) {
 588                 r = -errno;
 589                 goto finish;
 590         }
 591
 592         socket_fd = create_socket(&socket_name);
 593         if (socket_fd < 0) {
 594                 r = socket_fd;
 595                 goto finish;
 596         }
 597
 598         fprintf(f,
 599                 "[Ask]\n"
 600                 "PID="PID_FMT"\n"
 601                 "Socket=%s\n"
 602                 "AcceptCached=%i\n"
 603                 "Echo=%i\n"
 604                 "NotAfter="USEC_FMT"\n",
 605                 getpid_cached(),
 606                 socket_name,
 607                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 608                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 609                 until);
 610
 611         if (message)
 612                 fprintf(f, "Message=%s\n", message);
 613
 614         if (icon)
 615                 fprintf(f, "Icon=%s\n", icon);
 616
 617         if (id)
 618                 fprintf(f, "Id=%s\n", id);
 619
 620         r = fflush_and_check(f);
 621         if (r < 0)
 622                 goto finish;
 623
 624         memcpy(final, temp, sizeof(temp));
 625
 626         final[sizeof(final)-11] = 'a';
 627         final[sizeof(final)-10] = 's';
 628         final[sizeof(final)-9] = 'k';
 629
 630         if (rename(temp, final) < 0) {
 631                 r = -errno;
 632                 goto finish;
 633         }
 634
 635         zero(pollfd);
 636         pollfd[FD_SOCKET].fd = socket_fd;
 637         pollfd[FD_SOCKET].events = POLLIN;
 638         pollfd[FD_SIGNAL].fd = signal_fd;
 639         pollfd[FD_SIGNAL].events = POLLIN;
 640         pollfd[FD_INOTIFY].fd = notify;
 641         pollfd[FD_INOTIFY].events = POLLIN;
 642
 643         for (;;) {
 644                 char passphrase[LINE_MAX+1];
 645                 struct msghdr msghdr;
 646                 struct iovec iovec;
 647                 struct ucred *ucred;
 648                 union {
 649                         struct cmsghdr cmsghdr;
 650                         uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
 651                 } control;
 652                 ssize_t n;
 653                 int k;
 654                 usec_t t;
 655
 656                 t = now(CLOCK_MONOTONIC);
 657
 658                 if (until > 0 && until <= t) {
 659                         r = -ETIME;
 660                         goto finish;
 661                 }
 662
 663                 k = poll(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1);
 664                 if (k < 0) {
 665                         if (errno == EINTR)
 666                                 continue;
 667
 668                         r = -errno;
 669                         goto finish;
 670                 }
 671
 672                 if (k <= 0) {
 673                         r = -ETIME;
 674                         goto finish;
 675                 }
 676
 677                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 678                         r = -EINTR;
 679                         goto finish;
 680                 }
 681
 682                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 683                         (void) flush_fd(notify);
 684
 685                         r = ask_password_keyring(keyname, flags, ret);
 686                         if (r >= 0) {
 687                                 r = 0;
 688                                 goto finish;
 689                         } else if (r != -ENOKEY)
 690                                 goto finish;
 691                 }
 692
 693                 if (pollfd[FD_SOCKET].revents == 0)
 694                         continue;
 695
 696                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 697                         r = -EIO;
 698                         goto finish;
 699                 }
 700
 701                 zero(iovec);
 702                 iovec.iov_base = passphrase;
 703                 iovec.iov_len = sizeof(passphrase);
 704
 705                 zero(control);
 706                 zero(msghdr);
 707                 msghdr.msg_iov = &iovec;
 708                 msghdr.msg_iovlen = 1;
 709                 msghdr.msg_control = &control;
 710                 msghdr.msg_controllen = sizeof(control);
 711
 712                 n = recvmsg(socket_fd, &msghdr, 0);
 713                 if (n < 0) {
 714                         if (IN_SET(errno, EAGAIN, EINTR))
 715                                 continue;
 716
 717                         r = -errno;
 718                         goto finish;
 719                 }
 720
 721                 cmsg_close_all(&msghdr);
 722
 723                 if (n <= 0) {
 724                         log_debug("Message too short");
 725                         continue;
 726                 }
 727
 728                 if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) ||
 729                     control.cmsghdr.cmsg_level != SOL_SOCKET ||
 730                     control.cmsghdr.cmsg_type != SCM_CREDENTIALS ||
 731                     control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
 732                         log_debug("Received message without credentials. Ignoring.");
 733                         continue;
 734                 }
 735
 736                 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
 737                 if (ucred->uid != 0) {
 738                         log_debug("Got request from unprivileged user. Ignoring.");
 739                         continue;
 740                 }
 741
 742                 if (passphrase[0] == '+') {
 743                         /* An empty message refers to the empty password */
 744                         if (n == 1)
 745                                 l = strv_new("");
 746                         else
 747                                 l = strv_parse_nulstr(passphrase+1, n-1);
 748                         explicit_bzero_safe(passphrase, n);
 749                         if (!l) {
 750                                 r = -ENOMEM;
 751                                 goto finish;
 752                         }
 753
 754                         if (strv_isempty(l)) {
 755                                 l = strv_free(l);
 756                                 log_debug("Invalid packet");
 757                                 continue;
 758                         }
 759
 760                         break;
 761                 }
 762
 763                 if (passphrase[0] == '-') {
 764                         r = -ECANCELED;
 765                         goto finish;
 766                 }
 767
 768                 log_debug("Invalid packet");
 769         }
 770
 771         if (keyname)
 772                 (void) add_to_keyring_and_log(keyname, flags, l);
 773
 774         *ret = TAKE_PTR(l);
 775         r = 0;
 776
 777 finish:
 778         if (socket_name)
 779                 (void) unlink(socket_name);
 780
 781         (void) unlink(temp);
 782
 783         if (final[0])
 784                 (void) unlink(final);
 785
 786         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 787         return r;
 788 }
 789
 790 int ask_password_auto(
 791                 const char *message,
 792                 const char *icon,
 793                 const char *id,
 794                 const char *keyname,
 795                 usec_t until,
 796                 AskPasswordFlags flags,
 797                 char ***ret) {
 798
 799         int r;
 800
 801         assert(ret);
 802
 803         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
 804             keyname &&
 805             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
 806             (flags & ASK_PASSWORD_NO_AGENT)) {
 807                 r = ask_password_keyring(keyname, flags, ret);
 808                 if (r != -ENOKEY)
 809                         return r;
 810         }
 811
 812         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
 813                 return ask_password_tty(-1, message, keyname, until, flags, NULL, ret);
 814
 815         if (!(flags & ASK_PASSWORD_NO_AGENT))
 816                 return ask_password_agent(message, icon, id, keyname, until, flags, ret);
 817
 818         return -EUNATCH;
 819 }