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 "plymouth-util.h"
  38 #include "process-util.h"
  39 #include "random-util.h"
  40 #include "signal-util.h"
  41 #include "socket-util.h"
  42 #include "string-util.h"
  43 #include "strv.h"
  44 #include "terminal-util.h"
  45 #include "time-util.h"
  46 #include "tmpfile-util.h"
  47 #include "umask-util.h"
  48 #include "utf8.h"
  49
  50 #define KEYRING_TIMEOUT_USEC ((5 * USEC_PER_MINUTE) / 2)
  51
  52 static int lookup_key(const char *keyname, key_serial_t *ret) {
  53         key_serial_t serial;
  54
  55         assert(keyname);
  56         assert(ret);
  57
  58         serial = request_key("user", keyname, NULL, 0);
  59         if (serial == -1)
  60                 return negative_errno();
  61
  62         *ret = serial;
  63         return 0;
  64 }
  65
  66 static int retrieve_key(key_serial_t serial, char ***ret) {
  67         size_t nfinal, m = 100;
  68         char **l;
  69         _cleanup_(erase_and_freep) char *pfinal = NULL;
  70
  71         assert(ret);
  72
  73         for (;;) {
  74                 _cleanup_(erase_and_freep) char *p = NULL;
  75                 long n;
  76
  77                 p = new(char, m);
  78                 if (!p)
  79                         return -ENOMEM;
  80
  81                 n = keyctl(KEYCTL_READ, (unsigned long) serial, (unsigned long) p, (unsigned long) m, 0);
  82                 if (n < 0)
  83                         return -errno;
  84                 if ((size_t) n < m) {
  85                         nfinal = (size_t) n;
  86                         pfinal = TAKE_PTR(p);
  87                         break;
  88                 }
  89
  90                 if (m > LONG_MAX / 2) /* overflow check */
  91                         return -ENOMEM;
  92                 m *= 2;
  93         }
  94
  95         l = strv_parse_nulstr(pfinal, nfinal);
  96         if (!l)
  97                 return -ENOMEM;
  98
  99         *ret = l;
 100         return 0;
 101 }
 102
 103 static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
 104         _cleanup_strv_free_erase_ char **l = NULL;
 105         _cleanup_(erase_and_freep) char *p = NULL;
 106         key_serial_t serial;
 107         size_t n;
 108         int r;
 109
 110         assert(keyname);
 111         assert(passwords);
 112
 113         if (!(flags & ASK_PASSWORD_PUSH_CACHE))
 114                 return 0;
 115
 116         r = lookup_key(keyname, &serial);
 117         if (r >= 0) {
 118                 r = retrieve_key(serial, &l);
 119                 if (r < 0)
 120                         return r;
 121         } else if (r != -ENOKEY)
 122                 return r;
 123
 124         r = strv_extend_strv(&l, passwords, true);
 125         if (r <= 0)
 126                 return r;
 127
 128         r = strv_make_nulstr(l, &p, &n);
 129         if (r < 0)
 130                 return r;
 131
 132         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 133         if (serial == -1)
 134                 return -errno;
 135
 136         if (keyctl(KEYCTL_SET_TIMEOUT,
 137                    (unsigned long) serial,
 138                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 139                 log_debug_errno(errno, "Failed to adjust timeout: %m");
 140
 141         /* Tell everyone to check the keyring */
 142         (void) touch("/run/systemd/ask-password");
 143
 144         log_debug("Added key to keyring as %" PRIi32 ".", serial);
 145
 146         return 1;
 147 }
 148
 149 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 150         int r;
 151
 152         assert(keyname);
 153         assert(passwords);
 154
 155         r = add_to_keyring(keyname, flags, passwords);
 156         if (r < 0)
 157                 return log_debug_errno(r, "Failed to add password to keyring: %m");
 158
 159         return 0;
 160 }
 161
 162 static int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
 163
 164         key_serial_t serial;
 165         int r;
 166
 167         assert(keyname);
 168         assert(ret);
 169
 170         if (!(flags & ASK_PASSWORD_ACCEPT_CACHED))
 171                 return -EUNATCH;
 172
 173         r = lookup_key(keyname, &serial);
 174         if (r == -ENOSYS) /* when retrieving the distinction doesn't matter */
 175                 return -ENOKEY;
 176         if (r < 0)
 177                 return r;
 178
 179         return retrieve_key(serial, ret);
 180 }
 181
 182 static int backspace_chars(int ttyfd, size_t p) {
 183         if (ttyfd < 0)
 184                 return 0;
 185
 186         _cleanup_free_ char *buf = malloc_multiply(3, p);
 187         if (!buf)
 188                 return log_oom();
 189
 190         for (size_t i = 0; i < p; i++)
 191                 memcpy(buf + 3 * i, "\b \b", 3);
 192
 193         return loop_write(ttyfd, buf, 3*p, false);
 194 }
 195
 196 static int backspace_string(int ttyfd, const char *str) {
 197         assert(str);
 198
 199         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 200
 201         if (ttyfd < 0)
 202                 return 0;
 203
 204         size_t m = utf8_n_codepoints(str);
 205         if (m == (size_t) -1)
 206                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes
 207                                   * output. Most likely this happened because we are not in an UTF-8 locale,
 208                                   * and in that case that is the correct thing to do. And even if it's not,
 209                                   * terminals tend to stop backspacing at the leftmost column, hence
 210                                   * backspacing too much should be mostly OK. */
 211
 212         return backspace_chars(ttyfd, m);
 213 }
 214
 215 int ask_password_plymouth(
 216                 const char *message,
 217                 usec_t until,
 218                 AskPasswordFlags flags,
 219                 const char *flag_file,
 220                 char ***ret) {
 221
 222         static const union sockaddr_union sa = PLYMOUTH_SOCKET;
 223         _cleanup_close_ int fd = -1, notify = -1;
 224         _cleanup_free_ char *packet = NULL;
 225         ssize_t k;
 226         int r, n;
 227         struct pollfd pollfd[2] = {};
 228         char buffer[LINE_MAX];
 229         size_t p = 0;
 230         enum {
 231                 POLL_SOCKET,
 232                 POLL_INOTIFY
 233         };
 234
 235         assert(ret);
 236
 237         if (flag_file) {
 238                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 239                 if (notify < 0)
 240                         return -errno;
 241
 242                 r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
 243                 if (r < 0)
 244                         return -errno;
 245         }
 246
 247         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 248         if (fd < 0)
 249                 return -errno;
 250
 251         r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 252         if (r < 0)
 253                 return -errno;
 254
 255         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 256                 packet = strdup("c");
 257                 n = 1;
 258         } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
 259                 packet = NULL;
 260         if (!packet)
 261                 return -ENOMEM;
 262
 263         r = loop_write(fd, packet, n + 1, true);
 264         if (r < 0)
 265                 return r;
 266
 267         pollfd[POLL_SOCKET].fd = fd;
 268         pollfd[POLL_SOCKET].events = POLLIN;
 269         pollfd[POLL_INOTIFY].fd = notify;
 270         pollfd[POLL_INOTIFY].events = POLLIN;
 271
 272         for (;;) {
 273                 int sleep_for = -1, j;
 274
 275                 if (until > 0) {
 276                         usec_t y;
 277
 278                         y = now(CLOCK_MONOTONIC);
 279
 280                         if (y > until) {
 281                                 r = -ETIME;
 282                                 goto finish;
 283                         }
 284
 285                         sleep_for = (int) ((until - y) / USEC_PER_MSEC);
 286                 }
 287
 288                 if (flag_file && access(flag_file, F_OK) < 0) {
 289                         r = -errno;
 290                         goto finish;
 291                 }
 292
 293                 j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 294                 if (j < 0) {
 295                         if (errno == EINTR)
 296                                 continue;
 297
 298                         r = -errno;
 299                         goto finish;
 300                 } else if (j == 0) {
 301                         r = -ETIME;
 302                         goto finish;
 303                 }
 304
 305                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
 306                         (void) flush_fd(notify);
 307
 308                 if (pollfd[POLL_SOCKET].revents == 0)
 309                         continue;
 310
 311                 k = read(fd, buffer + p, sizeof(buffer) - p);
 312                 if (k < 0) {
 313                         if (IN_SET(errno, EINTR, EAGAIN))
 314                                 continue;
 315
 316                         r = -errno;
 317                         goto finish;
 318                 } else if (k == 0) {
 319                         r = -EIO;
 320                         goto finish;
 321                 }
 322
 323                 p += k;
 324
 325                 if (p < 1)
 326                         continue;
 327
 328                 if (buffer[0] == 5) {
 329
 330                         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 331                                 /* Hmm, first try with cached
 332                                  * passwords failed, so let's retry
 333                                  * with a normal password request */
 334                                 packet = mfree(packet);
 335
 336                                 if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
 337                                         r = -ENOMEM;
 338                                         goto finish;
 339                                 }
 340
 341                                 r = loop_write(fd, packet, n+1, true);
 342                                 if (r < 0)
 343                                         goto finish;
 344
 345                                 flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
 346                                 p = 0;
 347                                 continue;
 348                         }
 349
 350                         /* No password, because UI not shown */
 351                         r = -ENOENT;
 352                         goto finish;
 353
 354                 } else if (IN_SET(buffer[0], 2, 9)) {
 355                         uint32_t size;
 356                         char **l;
 357
 358                         /* One or more answers */
 359                         if (p < 5)
 360                                 continue;
 361
 362                         memcpy(&size, buffer+1, sizeof(size));
 363                         size = le32toh(size);
 364                         if (size + 5 > sizeof(buffer)) {
 365                                 r = -EIO;
 366                                 goto finish;
 367                         }
 368
 369                         if (p-5 < size)
 370                                 continue;
 371
 372                         l = strv_parse_nulstr(buffer + 5, size);
 373                         if (!l) {
 374                                 r = -ENOMEM;
 375                                 goto finish;
 376                         }
 377
 378                         *ret = l;
 379                         break;
 380
 381                 } else {
 382                         /* Unknown packet */
 383                         r = -EIO;
 384                         goto finish;
 385                 }
 386         }
 387
 388         r = 0;
 389
 390 finish:
 391         explicit_bzero_safe(buffer, sizeof(buffer));
 392         return r;
 393 }
 394
 395 int ask_password_tty(
 396                 int ttyfd,
 397                 const char *message,
 398                 const char *keyname,
 399                 usec_t until,
 400                 AskPasswordFlags flags,
 401                 const char *flag_file,
 402                 char ***ret) {
 403
 404         enum {
 405                 POLL_TTY,
 406                 POLL_INOTIFY,
 407                 _POLL_MAX,
 408         };
 409
 410         bool reset_tty = false, dirty = false, use_color = false;
 411         _cleanup_close_ int cttyfd = -1, notify = -1;
 412         struct termios old_termios, new_termios;
 413         char passphrase[LINE_MAX + 1] = {}, *x;
 414         _cleanup_strv_free_erase_ char **l = NULL;
 415         struct pollfd pollfd[_POLL_MAX];
 416         size_t p = 0, codepoint = 0;
 417         int r;
 418
 419         assert(ret);
 420
 421         if (flags & ASK_PASSWORD_NO_TTY)
 422                 return -EUNATCH;
 423
 424         if (!message)
 425                 message = "Password:";
 426
 427         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 428                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 429                 if (notify < 0)
 430                         return -errno;
 431         }
 432         if (flag_file) {
 433                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 434                         return -errno;
 435         }
 436         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 437                 r = ask_password_keyring(keyname, flags, ret);
 438                 if (r >= 0)
 439                         return 0;
 440                 else if (r != -ENOKEY)
 441                         return r;
 442
 443                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 444                         return -errno;
 445         }
 446
 447         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 448         if (ttyfd < 0)
 449                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 450
 451         if (ttyfd >= 0) {
 452                 if (tcgetattr(ttyfd, &old_termios) < 0)
 453                         return -errno;
 454
 455                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 456                         use_color = dev_console_colors_enabled();
 457                 else
 458                         use_color = colors_enabled();
 459
 460                 if (use_color)
 461                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 462
 463                 (void) loop_write(ttyfd, message, strlen(message), false);
 464                 (void) loop_write(ttyfd, " ", 1, false);
 465
 466                 if (use_color)
 467                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 468
 469                 new_termios = old_termios;
 470                 new_termios.c_lflag &= ~(ICANON|ECHO);
 471                 new_termios.c_cc[VMIN] = 1;
 472                 new_termios.c_cc[VTIME] = 0;
 473
 474                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 475                         r = -errno;
 476                         goto finish;
 477                 }
 478
 479                 reset_tty = true;
 480         }
 481
 482         pollfd[POLL_TTY] = (struct pollfd) {
 483                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 484                 .events = POLLIN,
 485         };
 486         pollfd[POLL_INOTIFY] = (struct pollfd) {
 487                 .fd = notify,
 488                 .events = POLLIN,
 489         };
 490
 491         for (;;) {
 492                 _cleanup_(erase_char) char c;
 493                 int sleep_for = -1, k;
 494                 ssize_t n;
 495
 496                 if (until > 0) {
 497                         usec_t y;
 498
 499                         y = now(CLOCK_MONOTONIC);
 500
 501                         if (y > until) {
 502                                 r = -ETIME;
 503                                 goto finish;
 504                         }
 505
 506                         sleep_for = (int) DIV_ROUND_UP(until - y, USEC_PER_MSEC);
 507                 }
 508
 509                 if (flag_file)
 510                         if (access(flag_file, F_OK) < 0) {
 511                                 r = -errno;
 512                                 goto finish;
 513                         }
 514
 515                 k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 516                 if (k < 0) {
 517                         if (errno == EINTR)
 518                                 continue;
 519
 520                         r = -errno;
 521                         goto finish;
 522                 } else if (k == 0) {
 523                         r = -ETIME;
 524                         goto finish;
 525                 }
 526
 527                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
 528                         (void) flush_fd(notify);
 529
 530                         r = ask_password_keyring(keyname, flags, ret);
 531                         if (r >= 0) {
 532                                 r = 0;
 533                                 goto finish;
 534                         } else if (r != -ENOKEY)
 535                                 goto finish;
 536                 }
 537
 538                 if (pollfd[POLL_TTY].revents == 0)
 539                         continue;
 540
 541                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 542                 if (n < 0) {
 543                         if (IN_SET(errno, EINTR, EAGAIN))
 544                                 continue;
 545
 546                         r = -errno;
 547                         goto finish;
 548
 549                 }
 550
 551                 /* We treat EOF, newline and NUL byte all as valid end markers */
 552                 if (n == 0 || c == '\n' || c == 0)
 553                         break;
 554
 555                 if (c == 4) { /* C-d also known as EOT */
 556                         if (ttyfd >= 0)
 557                                 (void) loop_write(ttyfd, "(skipped)", 9, false);
 558
 559                         goto skipped;
 560                 }
 561
 562                 if (c == 21) { /* C-u */
 563
 564                         if (!(flags & ASK_PASSWORD_SILENT))
 565                                 (void) backspace_string(ttyfd, passphrase);
 566
 567                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 568                         p = codepoint = 0;
 569
 570                 } else if (IN_SET(c, '\b', 127)) {
 571
 572                         if (p > 0) {
 573                                 size_t q;
 574
 575                                 if (!(flags & ASK_PASSWORD_SILENT))
 576                                         (void) backspace_chars(ttyfd, 1);
 577
 578                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 579                                  * last one begins */
 580                                 q = 0;
 581                                 for (;;) {
 582                                         size_t z;
 583
 584                                         z = utf8_encoded_valid_unichar(passphrase + q, (size_t) -1);
 585                                         if (z == 0) {
 586                                                 q = (size_t) -1; /* Invalid UTF8! */
 587                                                 break;
 588                                         }
 589
 590                                         if (q + z >= p) /* This one brings us over the edge */
 591                                                 break;
 592
 593                                         q += z;
 594                                 }
 595
 596                                 p = codepoint = q == (size_t) -1 ? p - 1 : q;
 597                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 598
 599                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 600
 601                                 flags |= ASK_PASSWORD_SILENT;
 602
 603                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 604                                  * first key (and only as first key), or ... */
 605
 606                                 if (ttyfd >= 0)
 607                                         (void) loop_write(ttyfd, "(no echo) ", 10, false);
 608
 609                         } else if (ttyfd >= 0)
 610                                 (void) loop_write(ttyfd, "\a", 1, false);
 611
 612                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 613
 614                         (void) backspace_string(ttyfd, passphrase);
 615                         flags |= ASK_PASSWORD_SILENT;
 616
 617                         /* ... or by pressing TAB at any time. */
 618
 619                         if (ttyfd >= 0)
 620                                 (void) loop_write(ttyfd, "(no echo) ", 10, false);
 621
 622                 } else if (p >= sizeof(passphrase)-1) {
 623
 624                         /* Reached the size limit */
 625                         if (ttyfd >= 0)
 626                                 (void) loop_write(ttyfd, "\a", 1, false);
 627
 628                 } else {
 629                         passphrase[p++] = c;
 630
 631                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 632                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 633                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, (size_t) -1);
 634                                 if (n >= 0) {
 635                                         if (flags & ASK_PASSWORD_ECHO)
 636                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 637                                         else
 638                                                 (void) loop_write(ttyfd, "*", 1, false);
 639                                         codepoint = p;
 640                                 }
 641                         }
 642
 643                         dirty = true;
 644                 }
 645         }
 646
 647         x = strndup(passphrase, p);
 648         explicit_bzero_safe(passphrase, sizeof(passphrase));
 649         if (!x) {
 650                 r = -ENOMEM;
 651                 goto finish;
 652         }
 653
 654         r = strv_consume(&l, x);
 655         if (r < 0)
 656                 goto finish;
 657
 658 skipped:
 659         if (keyname)
 660                 (void) add_to_keyring_and_log(keyname, flags, l);
 661
 662         *ret = TAKE_PTR(l);
 663         r = 0;
 664
 665 finish:
 666         if (ttyfd >= 0 && reset_tty) {
 667                 (void) loop_write(ttyfd, "\n", 1, false);
 668                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 669         }
 670
 671         return r;
 672 }
 673
 674 static int create_socket(char **ret) {
 675         _cleanup_free_ char *path = NULL;
 676         union sockaddr_union sa = {};
 677         _cleanup_close_ int fd = -1;
 678         int salen, r;
 679
 680         assert(ret);
 681
 682         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 683         if (fd < 0)
 684                 return -errno;
 685
 686         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 687                 return -ENOMEM;
 688
 689         salen = sockaddr_un_set_path(&sa.un, path);
 690         if (salen < 0)
 691                 return salen;
 692
 693         RUN_WITH_UMASK(0177) {
 694                 if (bind(fd, &sa.sa, salen) < 0)
 695                         return -errno;
 696         }
 697
 698         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 699         if (r < 0)
 700                 return r;
 701
 702         *ret = TAKE_PTR(path);
 703         return TAKE_FD(fd);
 704 }
 705
 706 int ask_password_agent(
 707                 const char *message,
 708                 const char *icon,
 709                 const char *id,
 710                 const char *keyname,
 711                 usec_t until,
 712                 AskPasswordFlags flags,
 713                 char ***ret) {
 714
 715         enum {
 716                 FD_SOCKET,
 717                 FD_SIGNAL,
 718                 FD_INOTIFY,
 719                 _FD_MAX
 720         };
 721
 722         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 723         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 724         char final[sizeof(temp)] = "";
 725         _cleanup_free_ char *socket_name = NULL;
 726         _cleanup_strv_free_erase_ char **l = NULL;
 727         _cleanup_fclose_ FILE *f = NULL;
 728         struct pollfd pollfd[_FD_MAX];
 729         sigset_t mask, oldmask;
 730         int r;
 731
 732         assert(ret);
 733
 734         if (flags & ASK_PASSWORD_NO_AGENT)
 735                 return -EUNATCH;
 736
 737         assert_se(sigemptyset(&mask) >= 0);
 738         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 739         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 740
 741         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 742
 743         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 744                 r = ask_password_keyring(keyname, flags, ret);
 745                 if (r >= 0) {
 746                         r = 0;
 747                         goto finish;
 748                 } else if (r != -ENOKEY)
 749                         goto finish;
 750
 751                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 752                 if (notify < 0) {
 753                         r = -errno;
 754                         goto finish;
 755                 }
 756                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 757                         r = -errno;
 758                         goto finish;
 759                 }
 760         }
 761
 762         fd = mkostemp_safe(temp);
 763         if (fd < 0) {
 764                 r = fd;
 765                 goto finish;
 766         }
 767
 768         (void) fchmod(fd, 0644);
 769
 770         f = fdopen(fd, "w");
 771         if (!f) {
 772                 r = -errno;
 773                 goto finish;
 774         }
 775
 776         fd = -1;
 777
 778         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 779         if (signal_fd < 0) {
 780                 r = -errno;
 781                 goto finish;
 782         }
 783
 784         socket_fd = create_socket(&socket_name);
 785         if (socket_fd < 0) {
 786                 r = socket_fd;
 787                 goto finish;
 788         }
 789
 790         fprintf(f,
 791                 "[Ask]\n"
 792                 "PID="PID_FMT"\n"
 793                 "Socket=%s\n"
 794                 "AcceptCached=%i\n"
 795                 "Echo=%i\n"
 796                 "NotAfter="USEC_FMT"\n",
 797                 getpid_cached(),
 798                 socket_name,
 799                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 800                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 801                 until);
 802
 803         if (message)
 804                 fprintf(f, "Message=%s\n", message);
 805
 806         if (icon)
 807                 fprintf(f, "Icon=%s\n", icon);
 808
 809         if (id)
 810                 fprintf(f, "Id=%s\n", id);
 811
 812         r = fflush_and_check(f);
 813         if (r < 0)
 814                 goto finish;
 815
 816         memcpy(final, temp, sizeof(temp));
 817
 818         final[sizeof(final)-11] = 'a';
 819         final[sizeof(final)-10] = 's';
 820         final[sizeof(final)-9] = 'k';
 821
 822         if (rename(temp, final) < 0) {
 823                 r = -errno;
 824                 goto finish;
 825         }
 826
 827         zero(pollfd);
 828         pollfd[FD_SOCKET].fd = socket_fd;
 829         pollfd[FD_SOCKET].events = POLLIN;
 830         pollfd[FD_SIGNAL].fd = signal_fd;
 831         pollfd[FD_SIGNAL].events = POLLIN;
 832         pollfd[FD_INOTIFY].fd = notify;
 833         pollfd[FD_INOTIFY].events = POLLIN;
 834
 835         for (;;) {
 836                 char passphrase[LINE_MAX+1];
 837                 struct msghdr msghdr;
 838                 struct iovec iovec;
 839                 struct ucred *ucred;
 840                 union {
 841                         struct cmsghdr cmsghdr;
 842                         uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
 843                 } control;
 844                 ssize_t n;
 845                 int k;
 846                 usec_t t;
 847
 848                 t = now(CLOCK_MONOTONIC);
 849
 850                 if (until > 0 && until <= t) {
 851                         r = -ETIME;
 852                         goto finish;
 853                 }
 854
 855                 k = poll(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1);
 856                 if (k < 0) {
 857                         if (errno == EINTR)
 858                                 continue;
 859
 860                         r = -errno;
 861                         goto finish;
 862                 }
 863
 864                 if (k <= 0) {
 865                         r = -ETIME;
 866                         goto finish;
 867                 }
 868
 869                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 870                         r = -EINTR;
 871                         goto finish;
 872                 }
 873
 874                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 875                         (void) flush_fd(notify);
 876
 877                         r = ask_password_keyring(keyname, flags, ret);
 878                         if (r >= 0) {
 879                                 r = 0;
 880                                 goto finish;
 881                         } else if (r != -ENOKEY)
 882                                 goto finish;
 883                 }
 884
 885                 if (pollfd[FD_SOCKET].revents == 0)
 886                         continue;
 887
 888                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 889                         r = -EIO;
 890                         goto finish;
 891                 }
 892
 893                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 894
 895                 zero(control);
 896                 zero(msghdr);
 897                 msghdr.msg_iov = &iovec;
 898                 msghdr.msg_iovlen = 1;
 899                 msghdr.msg_control = &control;
 900                 msghdr.msg_controllen = sizeof(control);
 901
 902                 n = recvmsg(socket_fd, &msghdr, 0);
 903                 if (n < 0) {
 904                         if (IN_SET(errno, EAGAIN, EINTR))
 905                                 continue;
 906
 907                         r = -errno;
 908                         goto finish;
 909                 }
 910
 911                 cmsg_close_all(&msghdr);
 912
 913                 if (n <= 0) {
 914                         log_debug("Message too short");
 915                         continue;
 916                 }
 917
 918                 if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) ||
 919                     control.cmsghdr.cmsg_level != SOL_SOCKET ||
 920                     control.cmsghdr.cmsg_type != SCM_CREDENTIALS ||
 921                     control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
 922                         log_debug("Received message without credentials. Ignoring.");
 923                         continue;
 924                 }
 925
 926                 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
 927                 if (ucred->uid != 0) {
 928                         log_debug("Got request from unprivileged user. Ignoring.");
 929                         continue;
 930                 }
 931
 932                 if (passphrase[0] == '+') {
 933                         /* An empty message refers to the empty password */
 934                         if (n == 1)
 935                                 l = strv_new("");
 936                         else
 937                                 l = strv_parse_nulstr(passphrase+1, n-1);
 938                         explicit_bzero_safe(passphrase, n);
 939                         if (!l) {
 940                                 r = -ENOMEM;
 941                                 goto finish;
 942                         }
 943
 944                         if (strv_isempty(l)) {
 945                                 l = strv_free(l);
 946                                 log_debug("Invalid packet");
 947                                 continue;
 948                         }
 949
 950                         break;
 951                 }
 952
 953                 if (passphrase[0] == '-') {
 954                         r = -ECANCELED;
 955                         goto finish;
 956                 }
 957
 958                 log_debug("Invalid packet");
 959         }
 960
 961         if (keyname)
 962                 (void) add_to_keyring_and_log(keyname, flags, l);
 963
 964         *ret = TAKE_PTR(l);
 965         r = 0;
 966
 967 finish:
 968         if (socket_name)
 969                 (void) unlink(socket_name);
 970
 971         (void) unlink(temp);
 972
 973         if (final[0])
 974                 (void) unlink(final);
 975
 976         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 977         return r;
 978 }
 979
 980 int ask_password_auto(
 981                 const char *message,
 982                 const char *icon,
 983                 const char *id,
 984                 const char *keyname,
 985                 usec_t until,
 986                 AskPasswordFlags flags,
 987                 char ***ret) {
 988
 989         int r;
 990
 991         assert(ret);
 992
 993         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
 994             keyname &&
 995             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
 996             (flags & ASK_PASSWORD_NO_AGENT)) {
 997                 r = ask_password_keyring(keyname, flags, ret);
 998                 if (r != -ENOKEY)
 999                         return r;
1000         }
1001
1002         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
1003                 return ask_password_tty(-1, message, keyname, until, flags, NULL, ret);
1004
1005         if (!(flags & ASK_PASSWORD_NO_AGENT))
1006                 return ask_password_agent(message, icon, id, keyname, until, flags, ret);
1007
1008         return -EUNATCH;
1009 }