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