src/shared/ask-password-api.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <inttypes.h>
   6 #include <limits.h>
   7 #include <stdbool.h>
   8 #include <stddef.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <sys/inotify.h>
  13 #include <sys/signalfd.h>
  14 #include <sys/stat.h>
  15 #include <sys/time.h>
  16 #include <sys/uio.h>
  17 #include <sys/un.h>
  18 #include <termios.h>
  19 #include <unistd.h>
  20
  21 #include "alloc-util.h"
  22 #include "ask-password-api.h"
  23 #include "constants.h"
  24 #include "creds-util.h"
  25 #include "fd-util.h"
  26 #include "fileio.h"
  27 #include "format-util.h"
  28 #include "fs-util.h"
  29 #include "glyph-util.h"
  30 #include "io-util.h"
  31 #include "keyring-util.h"
  32 #include "log.h"
  33 #include "macro.h"
  34 #include "memory-util.h"
  35 #include "missing_syscall.h"
  36 #include "mkdir-label.h"
  37 #include "nulstr-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         _cleanup_(erase_and_freep) void *p = NULL;
  68         char **l;
  69         size_t n;
  70         int r;
  71
  72         assert(ret);
  73
  74         r = keyring_read(serial, &p, &n);
  75         if (r < 0)
  76                 return r;
  77
  78         l = strv_parse_nulstr(p, n);
  79         if (!l)
  80                 return -ENOMEM;
  81
  82         *ret = l;
  83         return 0;
  84 }
  85
  86 static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
  87         _cleanup_strv_free_erase_ char **l = NULL;
  88         _cleanup_(erase_and_freep) char *p = NULL;
  89         key_serial_t serial;
  90         size_t n;
  91         int r;
  92
  93         assert(keyname);
  94
  95         if (!FLAGS_SET(flags, ASK_PASSWORD_PUSH_CACHE))
  96                 return 0;
  97         if (strv_isempty(passwords))
  98                 return 0;
  99
 100         r = lookup_key(keyname, &serial);
 101         if (r >= 0) {
 102                 r = retrieve_key(serial, &l);
 103                 if (r < 0)
 104                         return r;
 105         } else if (r != -ENOKEY)
 106                 return r;
 107
 108         r = strv_extend_strv(&l, passwords, true);
 109         if (r <= 0)
 110                 return r;
 111
 112         r = strv_make_nulstr(l, &p, &n);
 113         if (r < 0)
 114                 return r;
 115
 116         /* chop off the final NUL byte. We do this because we want to use the separator NUL bytes only if we
 117          * have multiple passwords. */
 118         n = LESS_BY(n, (size_t) 1);
 119
 120         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 121         if (serial == -1)
 122                 return -errno;
 123
 124         if (keyctl(KEYCTL_SET_TIMEOUT,
 125                    (unsigned long) serial,
 126                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 127                 log_debug_errno(errno, "Failed to adjust kernel keyring key timeout: %m");
 128
 129         /* Tell everyone to check the keyring */
 130         (void) touch("/run/systemd/ask-password");
 131
 132         log_debug("Added key to kernel keyring as %" PRIi32 ".", serial);
 133
 134         return 1;
 135 }
 136
 137 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 138         int r;
 139
 140         assert(keyname);
 141
 142         r = add_to_keyring(keyname, flags, passwords);
 143         if (r < 0)
 144                 return log_debug_errno(r, "Failed to add password to kernel keyring: %m");
 145
 146         return 0;
 147 }
 148
 149 static int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
 150
 151         key_serial_t serial;
 152         int r;
 153
 154         assert(keyname);
 155         assert(ret);
 156
 157         if (!FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED))
 158                 return -EUNATCH;
 159
 160         r = lookup_key(keyname, &serial);
 161         if (r < 0) {
 162                 /* when retrieving the distinction between "kernel or container manager don't support
 163                  * or allow this" and "no matching key known" doesn't matter. Note that we propagate
 164                  * EACCESS here (even if EPERM not) since that is used if the keyring is available but
 165                  * we lack access to the key. */
 166                 if (ERRNO_IS_NOT_SUPPORTED(r) || r == -EPERM)
 167                         return -ENOKEY;
 168
 169                 return r;
 170         }
 171
 172         return retrieve_key(serial, ret);
 173 }
 174
 175 static int backspace_chars(int ttyfd, size_t p) {
 176         if (ttyfd < 0)
 177                 return 0;
 178
 179         _cleanup_free_ char *buf = malloc_multiply(3, p);
 180         if (!buf)
 181                 return log_oom();
 182
 183         for (size_t i = 0; i < p; i++)
 184                 memcpy(buf + 3 * i, "\b \b", 3);
 185
 186         return loop_write(ttyfd, buf, 3*p, false);
 187 }
 188
 189 static int backspace_string(int ttyfd, const char *str) {
 190         assert(str);
 191
 192         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 193
 194         if (ttyfd < 0)
 195                 return 0;
 196
 197         size_t m = utf8_n_codepoints(str);
 198         if (m == SIZE_MAX)
 199                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes
 200                                   * output. Most likely this happened because we are not in an UTF-8 locale,
 201                                   * and in that case that is the correct thing to do. And even if it's not,
 202                                   * terminals tend to stop backspacing at the leftmost column, hence
 203                                   * backspacing too much should be mostly OK. */
 204
 205         return backspace_chars(ttyfd, m);
 206 }
 207
 208 int ask_password_plymouth(
 209                 const char *message,
 210                 usec_t until,
 211                 AskPasswordFlags flags,
 212                 const char *flag_file,
 213                 char ***ret) {
 214
 215         static const union sockaddr_union sa = PLYMOUTH_SOCKET;
 216         _cleanup_close_ int fd = -1, notify = -1;
 217         _cleanup_free_ char *packet = NULL;
 218         ssize_t k;
 219         int r, n;
 220         struct pollfd pollfd[2] = {};
 221         char buffer[LINE_MAX];
 222         size_t p = 0;
 223         enum {
 224                 POLL_SOCKET,
 225                 POLL_INOTIFY
 226         };
 227
 228         assert(ret);
 229
 230         if (!message)
 231                 message = "Password:";
 232
 233         if (flag_file) {
 234                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 235                 if (notify < 0)
 236                         return -errno;
 237
 238                 r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
 239                 if (r < 0)
 240                         return -errno;
 241         }
 242
 243         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 244         if (fd < 0)
 245                 return -errno;
 246
 247         r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 248         if (r < 0)
 249                 return -errno;
 250
 251         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED)) {
 252                 packet = strdup("c");
 253                 n = 1;
 254         } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
 255                 packet = NULL;
 256         if (!packet)
 257                 return -ENOMEM;
 258
 259         r = loop_write(fd, packet, n + 1, true);
 260         if (r < 0)
 261                 return r;
 262
 263         pollfd[POLL_SOCKET].fd = fd;
 264         pollfd[POLL_SOCKET].events = POLLIN;
 265         pollfd[POLL_INOTIFY].fd = notify;
 266         pollfd[POLL_INOTIFY].events = POLLIN;
 267
 268         for (;;) {
 269                 usec_t timeout;
 270
 271                 if (until > 0)
 272                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 273                 else
 274                         timeout = USEC_INFINITY;
 275
 276                 if (flag_file && access(flag_file, F_OK) < 0) {
 277                         r = -errno;
 278                         goto finish;
 279                 }
 280
 281                 r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
 282                 if (r == -EINTR)
 283                         continue;
 284                 if (r < 0)
 285                         goto finish;
 286                 if (r == 0) {
 287                         r = -ETIME;
 288                         goto finish;
 289                 }
 290
 291                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
 292                         (void) flush_fd(notify);
 293
 294                 if (pollfd[POLL_SOCKET].revents == 0)
 295                         continue;
 296
 297                 k = read(fd, buffer + p, sizeof(buffer) - p);
 298                 if (k < 0) {
 299                         if (ERRNO_IS_TRANSIENT(errno))
 300                                 continue;
 301
 302                         r = -errno;
 303                         goto finish;
 304                 }
 305                 if (k == 0) {
 306                         r = -EIO;
 307                         goto finish;
 308                 }
 309
 310                 p += k;
 311
 312                 if (buffer[0] == 5) {
 313
 314                         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED)) {
 315                                 /* Hmm, first try with cached
 316                                  * passwords failed, so let's retry
 317                                  * with a normal password request */
 318                                 packet = mfree(packet);
 319
 320                                 if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
 321                                         r = -ENOMEM;
 322                                         goto finish;
 323                                 }
 324
 325                                 r = loop_write(fd, packet, n+1, true);
 326                                 if (r < 0)
 327                                         goto finish;
 328
 329                                 flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
 330                                 p = 0;
 331                                 continue;
 332                         }
 333
 334                         /* No password, because UI not shown */
 335                         r = -ENOENT;
 336                         goto finish;
 337
 338                 } else if (IN_SET(buffer[0], 2, 9)) {
 339                         uint32_t size;
 340                         char **l;
 341
 342                         /* One or more answers */
 343                         if (p < 5)
 344                                 continue;
 345
 346                         memcpy(&size, buffer+1, sizeof(size));
 347                         size = le32toh(size);
 348                         if (size + 5 > sizeof(buffer)) {
 349                                 r = -EIO;
 350                                 goto finish;
 351                         }
 352
 353                         if (p-5 < size)
 354                                 continue;
 355
 356                         l = strv_parse_nulstr(buffer + 5, size);
 357                         if (!l) {
 358                                 r = -ENOMEM;
 359                                 goto finish;
 360                         }
 361
 362                         *ret = l;
 363                         break;
 364
 365                 } else {
 366                         /* Unknown packet */
 367                         r = -EIO;
 368                         goto finish;
 369                 }
 370         }
 371
 372         r = 0;
 373
 374 finish:
 375         explicit_bzero_safe(buffer, sizeof(buffer));
 376         return r;
 377 }
 378
 379 #define NO_ECHO "(no echo) "
 380 #define PRESS_TAB "(press TAB for no echo) "
 381 #define SKIPPED "(skipped)"
 382
 383 int ask_password_tty(
 384                 int ttyfd,
 385                 const char *message,
 386                 const char *keyname,
 387                 usec_t until,
 388                 AskPasswordFlags flags,
 389                 const char *flag_file,
 390                 char ***ret) {
 391
 392         enum {
 393                 POLL_TTY,
 394                 POLL_INOTIFY,
 395                 _POLL_MAX,
 396         };
 397
 398         bool reset_tty = false, dirty = false, use_color = false, press_tab_visible = false;
 399         _cleanup_close_ int cttyfd = -1, notify = -1;
 400         struct termios old_termios, new_termios;
 401         char passphrase[LINE_MAX + 1] = {}, *x;
 402         _cleanup_strv_free_erase_ char **l = NULL;
 403         struct pollfd pollfd[_POLL_MAX];
 404         size_t p = 0, codepoint = 0;
 405         int r;
 406
 407         assert(ret);
 408
 409         if (FLAGS_SET(flags, ASK_PASSWORD_NO_TTY))
 410                 return -EUNATCH;
 411
 412         if (!message)
 413                 message = "Password:";
 414
 415         if (!FLAGS_SET(flags, ASK_PASSWORD_HIDE_EMOJI) && emoji_enabled())
 416                 message = strjoina(special_glyph(SPECIAL_GLYPH_LOCK_AND_KEY), " ", message);
 417
 418         if (flag_file || (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 419                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 420                 if (notify < 0)
 421                         return -errno;
 422         }
 423         if (flag_file) {
 424                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 425                         return -errno;
 426         }
 427         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 428                 r = ask_password_keyring(keyname, flags, ret);
 429                 if (r >= 0)
 430                         return 0;
 431                 else if (r != -ENOKEY)
 432                         return r;
 433
 434                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 435                         return -errno;
 436         }
 437
 438         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 439         if (ttyfd < 0)
 440                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 441
 442         if (ttyfd >= 0) {
 443                 if (tcgetattr(ttyfd, &old_termios) < 0)
 444                         return -errno;
 445
 446                 if (FLAGS_SET(flags, ASK_PASSWORD_CONSOLE_COLOR))
 447                         use_color = dev_console_colors_enabled();
 448                 else
 449                         use_color = colors_enabled();
 450
 451                 if (use_color)
 452                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 453
 454                 (void) loop_write(ttyfd, message, strlen(message), false);
 455                 (void) loop_write(ttyfd, " ", 1, false);
 456
 457                 if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT) && !FLAGS_SET(flags, ASK_PASSWORD_ECHO)) {
 458                         if (use_color)
 459                                 (void) loop_write(ttyfd, ansi_grey(), strlen(ansi_grey()), false);
 460                         (void) loop_write(ttyfd, PRESS_TAB, strlen(PRESS_TAB), false);
 461                         press_tab_visible = true;
 462                 }
 463
 464                 if (use_color)
 465                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 466
 467                 new_termios = old_termios;
 468                 new_termios.c_lflag &= ~(ICANON|ECHO);
 469                 new_termios.c_cc[VMIN] = 1;
 470                 new_termios.c_cc[VTIME] = 0;
 471
 472                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 473                         r = -errno;
 474                         goto finish;
 475                 }
 476
 477                 reset_tty = true;
 478         }
 479
 480         pollfd[POLL_TTY] = (struct pollfd) {
 481                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 482                 .events = POLLIN,
 483         };
 484         pollfd[POLL_INOTIFY] = (struct pollfd) {
 485                 .fd = notify,
 486                 .events = POLLIN,
 487         };
 488
 489         for (;;) {
 490                 _cleanup_(erase_char) char c;
 491                 usec_t timeout;
 492                 ssize_t n;
 493
 494                 if (until > 0)
 495                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 496                 else
 497                         timeout = USEC_INFINITY;
 498
 499                 if (flag_file)
 500                         if (access(flag_file, F_OK) < 0) {
 501                                 r = -errno;
 502                                 goto finish;
 503                         }
 504
 505                 r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
 506                 if (r == -EINTR)
 507                         continue;
 508                 if (r < 0)
 509                         goto finish;
 510                 if (r == 0) {
 511                         r = -ETIME;
 512                         goto finish;
 513                 }
 514
 515                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
 516                         (void) flush_fd(notify);
 517
 518                         r = ask_password_keyring(keyname, flags, ret);
 519                         if (r >= 0) {
 520                                 r = 0;
 521                                 goto finish;
 522                         } else if (r != -ENOKEY)
 523                                 goto finish;
 524                 }
 525
 526                 if (pollfd[POLL_TTY].revents == 0)
 527                         continue;
 528
 529                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 530                 if (n < 0) {
 531                         if (ERRNO_IS_TRANSIENT(errno))
 532                                 continue;
 533
 534                         r = -errno;
 535                         goto finish;
 536
 537                 }
 538
 539                 if (press_tab_visible) {
 540                         assert(ttyfd >= 0);
 541                         backspace_chars(ttyfd, strlen(PRESS_TAB));
 542                         press_tab_visible = false;
 543                 }
 544
 545                 /* We treat EOF, newline and NUL byte all as valid end markers */
 546                 if (n == 0 || c == '\n' || c == 0)
 547                         break;
 548
 549                 if (c == 4) { /* C-d also known as EOT */
 550                         if (ttyfd >= 0)
 551                                 (void) loop_write(ttyfd, SKIPPED, strlen(SKIPPED), false);
 552
 553                         goto skipped;
 554                 }
 555
 556                 if (c == 21) { /* C-u */
 557
 558                         if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT))
 559                                 (void) backspace_string(ttyfd, passphrase);
 560
 561                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 562                         p = codepoint = 0;
 563
 564                 } else if (IN_SET(c, '\b', 127)) {
 565
 566                         if (p > 0) {
 567                                 size_t q;
 568
 569                                 if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT))
 570                                         (void) backspace_chars(ttyfd, 1);
 571
 572                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 573                                  * last one begins */
 574                                 q = 0;
 575                                 for (;;) {
 576                                         int z;
 577
 578                                         z = utf8_encoded_valid_unichar(passphrase + q, SIZE_MAX);
 579                                         if (z <= 0) {
 580                                                 q = SIZE_MAX; /* Invalid UTF8! */
 581                                                 break;
 582                                         }
 583
 584                                         if (q + z >= p) /* This one brings us over the edge */
 585                                                 break;
 586
 587                                         q += z;
 588                                 }
 589
 590                                 p = codepoint = q == SIZE_MAX ? p - 1 : q;
 591                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 592
 593                         } else if (!dirty && !FLAGS_SET(flags, ASK_PASSWORD_SILENT)) {
 594
 595                                 flags |= ASK_PASSWORD_SILENT;
 596
 597                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 598                                  * first key (and only as first key), or ... */
 599
 600                                 if (ttyfd >= 0)
 601                                         (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 602
 603                         } else if (ttyfd >= 0)
 604                                 (void) loop_write(ttyfd, "\a", 1, false);
 605
 606                 } else if (c == '\t' && !FLAGS_SET(flags, ASK_PASSWORD_SILENT)) {
 607
 608                         (void) backspace_string(ttyfd, passphrase);
 609                         flags |= ASK_PASSWORD_SILENT;
 610
 611                         /* ... or by pressing TAB at any time. */
 612
 613                         if (ttyfd >= 0)
 614                                 (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 615
 616                 } else if (p >= sizeof(passphrase)-1) {
 617
 618                         /* Reached the size limit */
 619                         if (ttyfd >= 0)
 620                                 (void) loop_write(ttyfd, "\a", 1, false);
 621
 622                 } else {
 623                         passphrase[p++] = c;
 624
 625                         if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 626                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 627                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, SIZE_MAX);
 628                                 if (n >= 0) {
 629                                         if (FLAGS_SET(flags, ASK_PASSWORD_ECHO))
 630                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 631                                         else
 632                                                 (void) loop_write(ttyfd, "*", 1, false);
 633                                         codepoint = p;
 634                                 }
 635                         }
 636
 637                         dirty = true;
 638                 }
 639         }
 640
 641         x = strndup(passphrase, p);
 642         explicit_bzero_safe(passphrase, sizeof(passphrase));
 643         if (!x) {
 644                 r = -ENOMEM;
 645                 goto finish;
 646         }
 647
 648         r = strv_consume(&l, x);
 649         if (r < 0)
 650                 goto finish;
 651
 652 skipped:
 653         if (strv_isempty(l))
 654                 r = log_debug_errno(SYNTHETIC_ERRNO(ECANCELED), "Password query was cancelled.");
 655         else {
 656                 if (keyname)
 657                         (void) add_to_keyring_and_log(keyname, flags, l);
 658
 659                 *ret = TAKE_PTR(l);
 660                 r = 0;
 661         }
 662
 663 finish:
 664         if (ttyfd >= 0 && reset_tty) {
 665                 (void) loop_write(ttyfd, "\n", 1, false);
 666                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 667         }
 668
 669         return r;
 670 }
 671
 672 static int create_socket(char **ret) {
 673         _cleanup_free_ char *path = NULL;
 674         union sockaddr_union sa;
 675         socklen_t sa_len;
 676         _cleanup_close_ int fd = -1;
 677         int r;
 678
 679         assert(ret);
 680
 681         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 682         if (fd < 0)
 683                 return -errno;
 684
 685         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 686                 return -ENOMEM;
 687
 688         r = sockaddr_un_set_path(&sa.un, path);
 689         if (r < 0)
 690                 return r;
 691         sa_len = r;
 692
 693         RUN_WITH_UMASK(0177)
 694                 if (bind(fd, &sa.sa, sa_len) < 0)
 695                         return -errno;
 696
 697         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 698         if (r < 0)
 699                 return r;
 700
 701         *ret = TAKE_PTR(path);
 702         return TAKE_FD(fd);
 703 }
 704
 705 int ask_password_agent(
 706                 const char *message,
 707                 const char *icon,
 708                 const char *id,
 709                 const char *keyname,
 710                 usec_t until,
 711                 AskPasswordFlags flags,
 712                 char ***ret) {
 713
 714         enum {
 715                 FD_SOCKET,
 716                 FD_SIGNAL,
 717                 FD_INOTIFY,
 718                 _FD_MAX
 719         };
 720
 721         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 722         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 723         char final[sizeof(temp)] = "";
 724         _cleanup_free_ char *socket_name = NULL;
 725         _cleanup_strv_free_erase_ char **l = NULL;
 726         _cleanup_fclose_ FILE *f = NULL;
 727         struct pollfd pollfd[_FD_MAX];
 728         sigset_t mask, oldmask;
 729         int r;
 730
 731         assert(ret);
 732
 733         if (FLAGS_SET(flags, ASK_PASSWORD_NO_AGENT))
 734                 return -EUNATCH;
 735
 736         assert_se(sigemptyset(&mask) >= 0);
 737         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 738         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 739
 740         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 741
 742         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 743                 r = ask_password_keyring(keyname, flags, ret);
 744                 if (r >= 0) {
 745                         r = 0;
 746                         goto finish;
 747                 } else if (r != -ENOKEY)
 748                         goto finish;
 749
 750                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 751                 if (notify < 0) {
 752                         r = -errno;
 753                         goto finish;
 754                 }
 755                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 756                         r = -errno;
 757                         goto finish;
 758                 }
 759         }
 760
 761         fd = mkostemp_safe(temp);
 762         if (fd < 0) {
 763                 r = fd;
 764                 goto finish;
 765         }
 766
 767         (void) fchmod(fd, 0644);
 768
 769         f = take_fdopen(&fd, "w");
 770         if (!f) {
 771                 r = -errno;
 772                 goto finish;
 773         }
 774
 775         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 776         if (signal_fd < 0) {
 777                 r = -errno;
 778                 goto finish;
 779         }
 780
 781         socket_fd = create_socket(&socket_name);
 782         if (socket_fd < 0) {
 783                 r = socket_fd;
 784                 goto finish;
 785         }
 786
 787         fprintf(f,
 788                 "[Ask]\n"
 789                 "PID="PID_FMT"\n"
 790                 "Socket=%s\n"
 791                 "AcceptCached=%i\n"
 792                 "Echo=%i\n"
 793                 "NotAfter="USEC_FMT"\n"
 794                 "Silent=%i\n",
 795                 getpid_cached(),
 796                 socket_name,
 797                 FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED),
 798                 FLAGS_SET(flags, ASK_PASSWORD_ECHO),
 799                 until,
 800                 FLAGS_SET(flags, ASK_PASSWORD_SILENT));
 801
 802         if (message)
 803                 fprintf(f, "Message=%s\n", message);
 804
 805         if (icon)
 806                 fprintf(f, "Icon=%s\n", icon);
 807
 808         if (id)
 809                 fprintf(f, "Id=%s\n", id);
 810
 811         r = fflush_and_check(f);
 812         if (r < 0)
 813                 goto finish;
 814
 815         memcpy(final, temp, sizeof(temp));
 816
 817         final[sizeof(final)-11] = 'a';
 818         final[sizeof(final)-10] = 's';
 819         final[sizeof(final)-9] = 'k';
 820
 821         if (rename(temp, final) < 0) {
 822                 r = -errno;
 823                 goto finish;
 824         }
 825
 826         zero(pollfd);
 827         pollfd[FD_SOCKET].fd = socket_fd;
 828         pollfd[FD_SOCKET].events = POLLIN;
 829         pollfd[FD_SIGNAL].fd = signal_fd;
 830         pollfd[FD_SIGNAL].events = POLLIN;
 831         pollfd[FD_INOTIFY].fd = notify;
 832         pollfd[FD_INOTIFY].events = POLLIN;
 833
 834         for (;;) {
 835                 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
 836                 char passphrase[LINE_MAX+1];
 837                 struct iovec iovec;
 838                 struct ucred *ucred;
 839                 usec_t timeout;
 840                 ssize_t n;
 841
 842                 if (until > 0)
 843                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 844                 else
 845                         timeout = USEC_INFINITY;
 846
 847                 r = ppoll_usec(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, timeout);
 848                 if (r == -EINTR)
 849                         continue;
 850                 if (r < 0)
 851                         goto finish;
 852                 if (r == 0) {
 853                         r = -ETIME;
 854                         goto finish;
 855                 }
 856
 857                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 858                         r = -EINTR;
 859                         goto finish;
 860                 }
 861
 862                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 863                         (void) flush_fd(notify);
 864
 865                         r = ask_password_keyring(keyname, flags, ret);
 866                         if (r >= 0) {
 867                                 r = 0;
 868                                 goto finish;
 869                         } else if (r != -ENOKEY)
 870                                 goto finish;
 871                 }
 872
 873                 if (pollfd[FD_SOCKET].revents == 0)
 874                         continue;
 875
 876                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 877                         r = -EIO;
 878                         goto finish;
 879                 }
 880
 881                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 882
 883                 struct msghdr msghdr = {
 884                         .msg_iov = &iovec,
 885                         .msg_iovlen = 1,
 886                         .msg_control = &control,
 887                         .msg_controllen = sizeof(control),
 888                 };
 889
 890                 n = recvmsg_safe(socket_fd, &msghdr, 0);
 891                 if (n < 0) {
 892                         if (ERRNO_IS_TRANSIENT(n))
 893                                 continue;
 894                         if (n == -EXFULL) {
 895                                 log_debug("Got message with truncated control data, ignoring.");
 896                                 continue;
 897                         }
 898
 899                         r = (int) n;
 900                         goto finish;
 901                 }
 902
 903                 cmsg_close_all(&msghdr);
 904
 905                 if (n == 0) {
 906                         log_debug("Message too short");
 907                         continue;
 908                 }
 909
 910                 ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
 911                 if (!ucred) {
 912                         log_debug("Received message without credentials. Ignoring.");
 913                         continue;
 914                 }
 915
 916                 if (ucred->uid != 0) {
 917                         log_debug("Got request from unprivileged user. Ignoring.");
 918                         continue;
 919                 }
 920
 921                 if (passphrase[0] == '+') {
 922                         /* An empty message refers to the empty password */
 923                         if (n == 1)
 924                                 l = strv_new("");
 925                         else
 926                                 l = strv_parse_nulstr(passphrase+1, n-1);
 927                         explicit_bzero_safe(passphrase, n);
 928                         if (!l) {
 929                                 r = -ENOMEM;
 930                                 goto finish;
 931                         }
 932
 933                         if (strv_isempty(l)) {
 934                                 l = strv_free(l);
 935                                 log_debug("Invalid packet");
 936                                 continue;
 937                         }
 938
 939                         break;
 940                 }
 941
 942                 if (passphrase[0] == '-') {
 943                         r = -ECANCELED;
 944                         goto finish;
 945                 }
 946
 947                 log_debug("Invalid packet");
 948         }
 949
 950         if (keyname)
 951                 (void) add_to_keyring_and_log(keyname, flags, l);
 952
 953         *ret = TAKE_PTR(l);
 954         r = 0;
 955
 956 finish:
 957         if (socket_name)
 958                 (void) unlink(socket_name);
 959
 960         (void) unlink(temp);
 961
 962         if (final[0])
 963                 (void) unlink(final);
 964
 965         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 966         return r;
 967 }
 968
 969 static int ask_password_credential(const char *credential_name, AskPasswordFlags flags, char ***ret) {
 970         _cleanup_(erase_and_freep) char *buffer = NULL;
 971         size_t size;
 972         char **l;
 973         int r;
 974
 975         assert(credential_name);
 976         assert(ret);
 977
 978         r = read_credential(credential_name, (void**) &buffer, &size);
 979         if (IN_SET(r, -ENXIO, -ENOENT)) /* No credentials passed or this credential not defined? */
 980                 return -ENOKEY;
 981
 982         l = strv_parse_nulstr(buffer, size);
 983         if (!l)
 984                 return -ENOMEM;
 985
 986         *ret = l;
 987         return 0;
 988 }
 989
 990 int ask_password_auto(
 991                 const char *message,
 992                 const char *icon,
 993                 const char *id,                /* id in "ask-password" protocol */
 994                 const char *key_name,          /* name in kernel keyring */
 995                 const char *credential_name,   /* name in $CREDENTIALS_DIRECTORY directory */
 996                 usec_t until,
 997                 AskPasswordFlags flags,
 998                 char ***ret) {
 999
1000         int r;
1001
1002         assert(ret);
1003
1004         if (!FLAGS_SET(flags, ASK_PASSWORD_NO_CREDENTIAL) && credential_name) {
1005                 r = ask_password_credential(credential_name, flags, ret);
1006                 if (r != -ENOKEY)
1007                         return r;
1008         }
1009
1010         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) &&
1011             key_name &&
1012             (FLAGS_SET(flags, ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
1013             FLAGS_SET(flags, ASK_PASSWORD_NO_AGENT)) {
1014                 r = ask_password_keyring(key_name, flags, ret);
1015                 if (r != -ENOKEY)
1016                         return r;
1017         }
1018
1019         if (!FLAGS_SET(flags, ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
1020                 return ask_password_tty(-1, message, key_name, until, flags, NULL, ret);
1021
1022         if (!FLAGS_SET(flags, ASK_PASSWORD_NO_AGENT))
1023                 return ask_password_agent(message, icon, id, key_name, until, flags, ret);
1024
1025         return -EUNATCH;
1026 }