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