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 "memory-util.h"
  35 #include "missing.h"
  36 #include "mkdir.h"
  37 #include "process-util.h"
  38 #include "random-util.h"
  39 #include "signal-util.h"
  40 #include "socket-util.h"
  41 #include "string-util.h"
  42 #include "strv.h"
  43 #include "terminal-util.h"
  44 #include "time-util.h"
  45 #include "tmpfile-util.h"
  46 #include "umask-util.h"
  47 #include "utf8.h"
  48
  49 #define KEYRING_TIMEOUT_USEC ((5 * USEC_PER_MINUTE) / 2)
  50
  51 static int lookup_key(const char *keyname, key_serial_t *ret) {
  52         key_serial_t serial;
  53
  54         assert(keyname);
  55         assert(ret);
  56
  57         serial = request_key("user", keyname, NULL, 0);
  58         if (serial == -1)
  59                 return negative_errno();
  60
  61         *ret = serial;
  62         return 0;
  63 }
  64
  65 static int retrieve_key(key_serial_t serial, char ***ret) {
  66         _cleanup_free_ char *p = NULL;
  67         long m = 100, n;
  68         char **l;
  69
  70         assert(ret);
  71
  72         for (;;) {
  73                 p = new(char, m);
  74                 if (!p)
  75                         return -ENOMEM;
  76
  77                 n = keyctl(KEYCTL_READ, (unsigned long) serial, (unsigned long) p, (unsigned long) m, 0);
  78                 if (n < 0)
  79                         return -errno;
  80                 if (n < m)
  81                         break;
  82
  83                 explicit_bzero_safe(p, n);
  84
  85                 if (m > LONG_MAX / 2) /* overflow check */
  86                         return -ENOMEM;
  87                 m *= 2;
  88                 if ((long) (size_t) m != m) /* make sure that this still fits if converted to size_t */
  89                         return -ENOMEM;
  90
  91                 free(p);
  92         }
  93
  94         l = strv_parse_nulstr(p, n);
  95         if (!l)
  96                 return -ENOMEM;
  97
  98         explicit_bzero_safe(p, n);
  99
 100         *ret = l;
 101         return 0;
 102 }
 103
 104 static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
 105         _cleanup_strv_free_erase_ char **l = NULL;
 106         _cleanup_free_ char *p = NULL;
 107         key_serial_t serial;
 108         size_t n;
 109         int r;
 110
 111         assert(keyname);
 112         assert(passwords);
 113
 114         if (!(flags & ASK_PASSWORD_PUSH_CACHE))
 115                 return 0;
 116
 117         r = lookup_key(keyname, &serial);
 118         if (r >= 0) {
 119                 r = retrieve_key(serial, &l);
 120                 if (r < 0)
 121                         return r;
 122         } else if (r != -ENOKEY)
 123                 return r;
 124
 125         r = strv_extend_strv(&l, passwords, true);
 126         if (r <= 0)
 127                 return r;
 128
 129         r = strv_make_nulstr(l, &p, &n);
 130         if (r < 0)
 131                 return r;
 132
 133         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 134         explicit_bzero_safe(p, n);
 135         if (serial == -1)
 136                 return -errno;
 137
 138         if (keyctl(KEYCTL_SET_TIMEOUT,
 139                    (unsigned long) serial,
 140                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 141                 log_debug_errno(errno, "Failed to adjust timeout: %m");
 142
 143         /* Tell everyone to check the keyring */
 144         (void) touch("/run/systemd/ask-password");
 145
 146         log_debug("Added key to keyring as %" PRIi32 ".", serial);
 147
 148         return 1;
 149 }
 150
 151 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 152         int r;
 153
 154         assert(keyname);
 155         assert(passwords);
 156
 157         r = add_to_keyring(keyname, flags, passwords);
 158         if (r < 0)
 159                 return log_debug_errno(r, "Failed to add password to keyring: %m");
 160
 161         return 0;
 162 }
 163
 164 static int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
 165
 166         key_serial_t serial;
 167         int r;
 168
 169         assert(keyname);
 170         assert(ret);
 171
 172         if (!(flags & ASK_PASSWORD_ACCEPT_CACHED))
 173                 return -EUNATCH;
 174
 175         r = lookup_key(keyname, &serial);
 176         if (r == -ENOSYS) /* when retrieving the distinction doesn't matter */
 177                 return -ENOKEY;
 178         if (r < 0)
 179                 return r;
 180
 181         return retrieve_key(serial, ret);
 182 }
 183
 184 static void backspace_chars(int ttyfd, size_t p) {
 185
 186         if (ttyfd < 0)
 187                 return;
 188
 189         while (p > 0) {
 190                 p--;
 191
 192                 loop_write(ttyfd, "\b \b", 3, false);
 193         }
 194 }
 195
 196 static void backspace_string(int ttyfd, const char *str) {
 197         size_t m;
 198
 199         assert(str);
 200
 201         if (ttyfd < 0)
 202                 return;
 203
 204         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 205
 206         m = utf8_n_codepoints(str);
 207         if (m == (size_t) -1)
 208                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes output. Most
 209                                   * likely this happened because we are not in an UTF-8 locale, and in that case that
 210                                   * is the correct thing to do. And even if it's not, terminals tend to stop
 211                                   * backspacing at the leftmost column, hence backspacing too much should be mostly
 212                                   * OK. */
 213
 214         backspace_chars(ttyfd, m);
 215 }
 216
 217 int ask_password_tty(
 218                 int ttyfd,
 219                 const char *message,
 220                 const char *keyname,
 221                 usec_t until,
 222                 AskPasswordFlags flags,
 223                 const char *flag_file,
 224                 char ***ret) {
 225
 226         enum {
 227                 POLL_TTY,
 228                 POLL_INOTIFY,
 229                 _POLL_MAX,
 230         };
 231
 232         bool reset_tty = false, dirty = false, use_color = false;
 233         _cleanup_close_ int cttyfd = -1, notify = -1;
 234         struct termios old_termios, new_termios;
 235         char passphrase[LINE_MAX + 1] = {}, *x;
 236         _cleanup_strv_free_erase_ char **l = NULL;
 237         struct pollfd pollfd[_POLL_MAX];
 238         size_t p = 0, codepoint = 0;
 239         int r;
 240
 241         assert(ret);
 242
 243         if (flags & ASK_PASSWORD_NO_TTY)
 244                 return -EUNATCH;
 245
 246         if (!message)
 247                 message = "Password:";
 248
 249         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 250                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 251                 if (notify < 0)
 252                         return -errno;
 253         }
 254         if (flag_file) {
 255                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 256                         return -errno;
 257         }
 258         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 259                 r = ask_password_keyring(keyname, flags, ret);
 260                 if (r >= 0)
 261                         return 0;
 262                 else if (r != -ENOKEY)
 263                         return r;
 264
 265                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 266                         return -errno;
 267         }
 268
 269         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 270         if (ttyfd < 0)
 271                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 272
 273         if (ttyfd >= 0) {
 274                 if (tcgetattr(ttyfd, &old_termios) < 0)
 275                         return -errno;
 276
 277                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 278                         use_color = dev_console_colors_enabled();
 279                 else
 280                         use_color = colors_enabled();
 281
 282                 if (use_color)
 283                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 284
 285                 (void) loop_write(ttyfd, message, strlen(message), false);
 286                 (void) loop_write(ttyfd, " ", 1, false);
 287
 288                 if (use_color)
 289                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 290
 291                 new_termios = old_termios;
 292                 new_termios.c_lflag &= ~(ICANON|ECHO);
 293                 new_termios.c_cc[VMIN] = 1;
 294                 new_termios.c_cc[VTIME] = 0;
 295
 296                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 297                         r = -errno;
 298                         goto finish;
 299                 }
 300
 301                 reset_tty = true;
 302         }
 303
 304         pollfd[POLL_TTY] = (struct pollfd) {
 305                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 306                 .events = POLLIN,
 307         };
 308         pollfd[POLL_INOTIFY] = (struct pollfd) {
 309                 .fd = notify,
 310                 .events = POLLIN,
 311         };
 312
 313         for (;;) {
 314                 _cleanup_(erase_char) char c;
 315                 int sleep_for = -1, k;
 316                 ssize_t n;
 317
 318                 if (until > 0) {
 319                         usec_t y;
 320
 321                         y = now(CLOCK_MONOTONIC);
 322
 323                         if (y > until) {
 324                                 r = -ETIME;
 325                                 goto finish;
 326                         }
 327
 328                         sleep_for = (int) DIV_ROUND_UP(until - y, USEC_PER_MSEC);
 329                 }
 330
 331                 if (flag_file)
 332                         if (access(flag_file, F_OK) < 0) {
 333                                 r = -errno;
 334                                 goto finish;
 335                         }
 336
 337                 k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 338                 if (k < 0) {
 339                         if (errno == EINTR)
 340                                 continue;
 341
 342                         r = -errno;
 343                         goto finish;
 344                 } else if (k == 0) {
 345                         r = -ETIME;
 346                         goto finish;
 347                 }
 348
 349                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
 350                         (void) flush_fd(notify);
 351
 352                         r = ask_password_keyring(keyname, flags, ret);
 353                         if (r >= 0) {
 354                                 r = 0;
 355                                 goto finish;
 356                         } else if (r != -ENOKEY)
 357                                 goto finish;
 358                 }
 359
 360                 if (pollfd[POLL_TTY].revents == 0)
 361                         continue;
 362
 363                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 364                 if (n < 0) {
 365                         if (IN_SET(errno, EINTR, EAGAIN))
 366                                 continue;
 367
 368                         r = -errno;
 369                         goto finish;
 370
 371                 }
 372
 373                 /* We treat EOF, newline and NUL byte all as valid end markers */
 374                 if (n == 0 || c == '\n' || c == 0)
 375                         break;
 376
 377                 if (c == 21) { /* C-u */
 378
 379                         if (!(flags & ASK_PASSWORD_SILENT))
 380                                 backspace_string(ttyfd, passphrase);
 381
 382                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 383                         p = codepoint = 0;
 384
 385                 } else if (IN_SET(c, '\b', 127)) {
 386
 387                         if (p > 0) {
 388                                 size_t q;
 389
 390                                 if (!(flags & ASK_PASSWORD_SILENT))
 391                                         backspace_chars(ttyfd, 1);
 392
 393                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 394                                  * last one begins */
 395                                 q = 0;
 396                                 for (;;) {
 397                                         size_t z;
 398
 399                                         z = utf8_encoded_valid_unichar(passphrase + q, (size_t) -1);
 400                                         if (z == 0) {
 401                                                 q = (size_t) -1; /* Invalid UTF8! */
 402                                                 break;
 403                                         }
 404
 405                                         if (q + z >= p) /* This one brings us over the edge */
 406                                                 break;
 407
 408                                         q += z;
 409                                 }
 410
 411                                 p = codepoint = q == (size_t) -1 ? p - 1 : q;
 412                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 413
 414                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 415
 416                                 flags |= ASK_PASSWORD_SILENT;
 417
 418                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 419                                  * first key (and only as first key), or ... */
 420
 421                                 if (ttyfd >= 0)
 422                                         (void) loop_write(ttyfd, "(no echo) ", 10, false);
 423
 424                         } else if (ttyfd >= 0)
 425                                 (void) loop_write(ttyfd, "\a", 1, false);
 426
 427                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 428
 429                         backspace_string(ttyfd, passphrase);
 430                         flags |= ASK_PASSWORD_SILENT;
 431
 432                         /* ... or by pressing TAB at any time. */
 433
 434                         if (ttyfd >= 0)
 435                                 (void) loop_write(ttyfd, "(no echo) ", 10, false);
 436
 437                 } else if (p >= sizeof(passphrase)-1) {
 438
 439                         /* Reached the size limit */
 440                         if (ttyfd >= 0)
 441                                 (void) loop_write(ttyfd, "\a", 1, false);
 442
 443                 } else {
 444                         passphrase[p++] = c;
 445
 446                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 447                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 448                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, (size_t) -1);
 449                                 if (n >= 0) {
 450                                         if (flags & ASK_PASSWORD_ECHO)
 451                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 452                                         else
 453                                                 (void) loop_write(ttyfd, "*", 1, false);
 454                                         codepoint = p;
 455                                 }
 456                         }
 457
 458                         dirty = true;
 459                 }
 460         }
 461
 462         x = strndup(passphrase, p);
 463         explicit_bzero_safe(passphrase, sizeof(passphrase));
 464         if (!x) {
 465                 r = -ENOMEM;
 466                 goto finish;
 467         }
 468
 469         r = strv_consume(&l, x);
 470         if (r < 0)
 471                 goto finish;
 472
 473         if (keyname)
 474                 (void) add_to_keyring_and_log(keyname, flags, l);
 475
 476         *ret = TAKE_PTR(l);
 477         r = 0;
 478
 479 finish:
 480         if (ttyfd >= 0 && reset_tty) {
 481                 (void) loop_write(ttyfd, "\n", 1, false);
 482                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 483         }
 484
 485         return r;
 486 }
 487
 488 static int create_socket(char **ret) {
 489         _cleanup_free_ char *path = NULL;
 490         union sockaddr_union sa = {};
 491         _cleanup_close_ int fd = -1;
 492         int salen, r;
 493
 494         assert(ret);
 495
 496         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 497         if (fd < 0)
 498                 return -errno;
 499
 500         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 501                 return -ENOMEM;
 502
 503         salen = sockaddr_un_set_path(&sa.un, path);
 504         if (salen < 0)
 505                 return salen;
 506
 507         RUN_WITH_UMASK(0177) {
 508                 if (bind(fd, &sa.sa, salen) < 0)
 509                         return -errno;
 510         }
 511
 512         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 513         if (r < 0)
 514                 return r;
 515
 516         *ret = TAKE_PTR(path);
 517         return TAKE_FD(fd);
 518 }
 519
 520 int ask_password_agent(
 521                 const char *message,
 522                 const char *icon,
 523                 const char *id,
 524                 const char *keyname,
 525                 usec_t until,
 526                 AskPasswordFlags flags,
 527                 char ***ret) {
 528
 529         enum {
 530                 FD_SOCKET,
 531                 FD_SIGNAL,
 532                 FD_INOTIFY,
 533                 _FD_MAX
 534         };
 535
 536         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 537         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 538         char final[sizeof(temp)] = "";
 539         _cleanup_free_ char *socket_name = NULL;
 540         _cleanup_strv_free_erase_ char **l = NULL;
 541         _cleanup_fclose_ FILE *f = NULL;
 542         struct pollfd pollfd[_FD_MAX];
 543         sigset_t mask, oldmask;
 544         int r;
 545
 546         assert(ret);
 547
 548         if (flags & ASK_PASSWORD_NO_AGENT)
 549                 return -EUNATCH;
 550
 551         assert_se(sigemptyset(&mask) >= 0);
 552         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 553         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 554
 555         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 556
 557         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 558                 r = ask_password_keyring(keyname, flags, ret);
 559                 if (r >= 0) {
 560                         r = 0;
 561                         goto finish;
 562                 } else if (r != -ENOKEY)
 563                         goto finish;
 564
 565                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 566                 if (notify < 0) {
 567                         r = -errno;
 568                         goto finish;
 569                 }
 570                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 571                         r = -errno;
 572                         goto finish;
 573                 }
 574         }
 575
 576         fd = mkostemp_safe(temp);
 577         if (fd < 0) {
 578                 r = fd;
 579                 goto finish;
 580         }
 581
 582         (void) fchmod(fd, 0644);
 583
 584         f = fdopen(fd, "w");
 585         if (!f) {
 586                 r = -errno;
 587                 goto finish;
 588         }
 589
 590         fd = -1;
 591
 592         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 593         if (signal_fd < 0) {
 594                 r = -errno;
 595                 goto finish;
 596         }
 597
 598         socket_fd = create_socket(&socket_name);
 599         if (socket_fd < 0) {
 600                 r = socket_fd;
 601                 goto finish;
 602         }
 603
 604         fprintf(f,
 605                 "[Ask]\n"
 606                 "PID="PID_FMT"\n"
 607                 "Socket=%s\n"
 608                 "AcceptCached=%i\n"
 609                 "Echo=%i\n"
 610                 "NotAfter="USEC_FMT"\n",
 611                 getpid_cached(),
 612                 socket_name,
 613                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 614                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 615                 until);
 616
 617         if (message)
 618                 fprintf(f, "Message=%s\n", message);
 619
 620         if (icon)
 621                 fprintf(f, "Icon=%s\n", icon);
 622
 623         if (id)
 624                 fprintf(f, "Id=%s\n", id);
 625
 626         r = fflush_and_check(f);
 627         if (r < 0)
 628                 goto finish;
 629
 630         memcpy(final, temp, sizeof(temp));
 631
 632         final[sizeof(final)-11] = 'a';
 633         final[sizeof(final)-10] = 's';
 634         final[sizeof(final)-9] = 'k';
 635
 636         if (rename(temp, final) < 0) {
 637                 r = -errno;
 638                 goto finish;
 639         }
 640
 641         zero(pollfd);
 642         pollfd[FD_SOCKET].fd = socket_fd;
 643         pollfd[FD_SOCKET].events = POLLIN;
 644         pollfd[FD_SIGNAL].fd = signal_fd;
 645         pollfd[FD_SIGNAL].events = POLLIN;
 646         pollfd[FD_INOTIFY].fd = notify;
 647         pollfd[FD_INOTIFY].events = POLLIN;
 648
 649         for (;;) {
 650                 char passphrase[LINE_MAX+1];
 651                 struct msghdr msghdr;
 652                 struct iovec iovec;
 653                 struct ucred *ucred;
 654                 union {
 655                         struct cmsghdr cmsghdr;
 656                         uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
 657                 } control;
 658                 ssize_t n;
 659                 int k;
 660                 usec_t t;
 661
 662                 t = now(CLOCK_MONOTONIC);
 663
 664                 if (until > 0 && until <= t) {
 665                         r = -ETIME;
 666                         goto finish;
 667                 }
 668
 669                 k = poll(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1);
 670                 if (k < 0) {
 671                         if (errno == EINTR)
 672                                 continue;
 673
 674                         r = -errno;
 675                         goto finish;
 676                 }
 677
 678                 if (k <= 0) {
 679                         r = -ETIME;
 680                         goto finish;
 681                 }
 682
 683                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 684                         r = -EINTR;
 685                         goto finish;
 686                 }
 687
 688                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 689                         (void) flush_fd(notify);
 690
 691                         r = ask_password_keyring(keyname, flags, ret);
 692                         if (r >= 0) {
 693                                 r = 0;
 694                                 goto finish;
 695                         } else if (r != -ENOKEY)
 696                                 goto finish;
 697                 }
 698
 699                 if (pollfd[FD_SOCKET].revents == 0)
 700                         continue;
 701
 702                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 703                         r = -EIO;
 704                         goto finish;
 705                 }
 706
 707                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 708
 709                 zero(control);
 710                 zero(msghdr);
 711                 msghdr.msg_iov = &iovec;
 712                 msghdr.msg_iovlen = 1;
 713                 msghdr.msg_control = &control;
 714                 msghdr.msg_controllen = sizeof(control);
 715
 716                 n = recvmsg(socket_fd, &msghdr, 0);
 717                 if (n < 0) {
 718                         if (IN_SET(errno, EAGAIN, EINTR))
 719                                 continue;
 720
 721                         r = -errno;
 722                         goto finish;
 723                 }
 724
 725                 cmsg_close_all(&msghdr);
 726
 727                 if (n <= 0) {
 728                         log_debug("Message too short");
 729                         continue;
 730                 }
 731
 732                 if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) ||
 733                     control.cmsghdr.cmsg_level != SOL_SOCKET ||
 734                     control.cmsghdr.cmsg_type != SCM_CREDENTIALS ||
 735                     control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
 736                         log_debug("Received message without credentials. Ignoring.");
 737                         continue;
 738                 }
 739
 740                 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
 741                 if (ucred->uid != 0) {
 742                         log_debug("Got request from unprivileged user. Ignoring.");
 743                         continue;
 744                 }
 745
 746                 if (passphrase[0] == '+') {
 747                         /* An empty message refers to the empty password */
 748                         if (n == 1)
 749                                 l = strv_new("");
 750                         else
 751                                 l = strv_parse_nulstr(passphrase+1, n-1);
 752                         explicit_bzero_safe(passphrase, n);
 753                         if (!l) {
 754                                 r = -ENOMEM;
 755                                 goto finish;
 756                         }
 757
 758                         if (strv_isempty(l)) {
 759                                 l = strv_free(l);
 760                                 log_debug("Invalid packet");
 761                                 continue;
 762                         }
 763
 764                         break;
 765                 }
 766
 767                 if (passphrase[0] == '-') {
 768                         r = -ECANCELED;
 769                         goto finish;
 770                 }
 771
 772                 log_debug("Invalid packet");
 773         }
 774
 775         if (keyname)
 776                 (void) add_to_keyring_and_log(keyname, flags, l);
 777
 778         *ret = TAKE_PTR(l);
 779         r = 0;
 780
 781 finish:
 782         if (socket_name)
 783                 (void) unlink(socket_name);
 784
 785         (void) unlink(temp);
 786
 787         if (final[0])
 788                 (void) unlink(final);
 789
 790         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 791         return r;
 792 }
 793
 794 int ask_password_auto(
 795                 const char *message,
 796                 const char *icon,
 797                 const char *id,
 798                 const char *keyname,
 799                 usec_t until,
 800                 AskPasswordFlags flags,
 801                 char ***ret) {
 802
 803         int r;
 804
 805         assert(ret);
 806
 807         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
 808             keyname &&
 809             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
 810             (flags & ASK_PASSWORD_NO_AGENT)) {
 811                 r = ask_password_keyring(keyname, flags, ret);
 812                 if (r != -ENOKEY)
 813                         return r;
 814         }
 815
 816         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
 817                 return ask_password_tty(-1, message, keyname, until, flags, NULL, ret);
 818
 819         if (!(flags & ASK_PASSWORD_NO_AGENT))
 820                 return ask_password_agent(message, icon, id, keyname, until, flags, ret);
 821
 822         return -EUNATCH;
 823 }