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 "io-util.h"
  30 #include "locale-util.h"
  31 #include "log.h"
  32 #include "macro.h"
  33 #include "memory-util.h"
  34 #include "missing_syscall.h"
  35 #include "mkdir.h"
  36 #include "process-util.h"
  37 #include "random-util.h"
  38 #include "signal-util.h"
  39 #include "socket-util.h"
  40 #include "string-util.h"
  41 #include "strv.h"
  42 #include "terminal-util.h"
  43 #include "time-util.h"
  44 #include "tmpfile-util.h"
  45 #include "umask-util.h"
  46 #include "utf8.h"
  47
  48 #define KEYRING_TIMEOUT_USEC ((5 * USEC_PER_MINUTE) / 2)
  49
  50 static int lookup_key(const char *keyname, key_serial_t *ret) {
  51         key_serial_t serial;
  52
  53         assert(keyname);
  54         assert(ret);
  55
  56         serial = request_key("user", keyname, NULL, 0);
  57         if (serial == -1)
  58                 return negative_errno();
  59
  60         *ret = serial;
  61         return 0;
  62 }
  63
  64 static int retrieve_key(key_serial_t serial, char ***ret) {
  65         size_t nfinal, m = 100;
  66         char **l;
  67         _cleanup_(erase_and_freep) char *pfinal = NULL;
  68
  69         assert(ret);
  70
  71         for (;;) {
  72                 _cleanup_(erase_and_freep) char *p = NULL;
  73                 long n;
  74
  75                 p = new(char, m);
  76                 if (!p)
  77                         return -ENOMEM;
  78
  79                 n = keyctl(KEYCTL_READ, (unsigned long) serial, (unsigned long) p, (unsigned long) m, 0);
  80                 if (n < 0)
  81                         return -errno;
  82                 if ((size_t) n <= m) {
  83                         nfinal = (size_t) n;
  84                         pfinal = TAKE_PTR(p);
  85                         break;
  86                 }
  87
  88                 if (m > LONG_MAX / 2) /* overflow check */
  89                         return -ENOMEM;
  90                 m *= 2;
  91         }
  92
  93         l = strv_parse_nulstr(pfinal, nfinal);
  94         if (!l)
  95                 return -ENOMEM;
  96
  97         *ret = l;
  98         return 0;
  99 }
 100
 101 static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
 102         _cleanup_strv_free_erase_ char **l = NULL;
 103         _cleanup_(erase_and_freep) char *p = NULL;
 104         key_serial_t serial;
 105         size_t n;
 106         int r;
 107
 108         assert(keyname);
 109
 110         if (!(flags & ASK_PASSWORD_PUSH_CACHE))
 111                 return 0;
 112         if (strv_isempty(passwords))
 113                 return 0;
 114
 115         r = lookup_key(keyname, &serial);
 116         if (r >= 0) {
 117                 r = retrieve_key(serial, &l);
 118                 if (r < 0)
 119                         return r;
 120         } else if (r != -ENOKEY)
 121                 return r;
 122
 123         r = strv_extend_strv(&l, passwords, true);
 124         if (r <= 0)
 125                 return r;
 126
 127         r = strv_make_nulstr(l, &p, &n);
 128         if (r < 0)
 129                 return r;
 130
 131         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 132         if (serial == -1)
 133                 return -errno;
 134
 135         if (keyctl(KEYCTL_SET_TIMEOUT,
 136                    (unsigned long) serial,
 137                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 138                 log_debug_errno(errno, "Failed to adjust kernel keyring key timeout: %m");
 139
 140         /* Tell everyone to check the keyring */
 141         (void) touch("/run/systemd/ask-password");
 142
 143         log_debug("Added key to kernel keyring as %" PRIi32 ".", serial);
 144
 145         return 1;
 146 }
 147
 148 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 149         int r;
 150
 151         assert(keyname);
 152
 153         r = add_to_keyring(keyname, flags, passwords);
 154         if (r < 0)
 155                 return log_debug_errno(r, "Failed to add password to kernel keyring: %m");
 156
 157         return 0;
 158 }
 159
 160 static int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
 161
 162         key_serial_t serial;
 163         int r;
 164
 165         assert(keyname);
 166         assert(ret);
 167
 168         if (!(flags & ASK_PASSWORD_ACCEPT_CACHED))
 169                 return -EUNATCH;
 170
 171         r = lookup_key(keyname, &serial);
 172         if (ERRNO_IS_NOT_SUPPORTED(r) || r == -EPERM) /* when retrieving the distinction between "kernel or
 173                                                        * container manager don't support or allow this" and
 174                                                        * "no matching key known" doesn't matter. Note that we
 175                                                        * propagate EACCESS here (even if EPERM not) since
 176                                                        * that is used if the keyring is available but we lack
 177                                                        * access to the key. */
 178                 return -ENOKEY;
 179         if (r < 0)
 180                 return r;
 181
 182         return retrieve_key(serial, ret);
 183 }
 184
 185 static int backspace_chars(int ttyfd, size_t p) {
 186         if (ttyfd < 0)
 187                 return 0;
 188
 189         _cleanup_free_ char *buf = malloc_multiply(3, p);
 190         if (!buf)
 191                 return log_oom();
 192
 193         for (size_t i = 0; i < p; i++)
 194                 memcpy(buf + 3 * i, "\b \b", 3);
 195
 196         return loop_write(ttyfd, buf, 3*p, false);
 197 }
 198
 199 static int backspace_string(int ttyfd, const char *str) {
 200         assert(str);
 201
 202         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 203
 204         if (ttyfd < 0)
 205                 return 0;
 206
 207         size_t m = utf8_n_codepoints(str);
 208         if (m == SIZE_MAX)
 209                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes
 210                                   * output. Most likely this happened because we are not in an UTF-8 locale,
 211                                   * and in that case that is the correct thing to do. And even if it's not,
 212                                   * terminals tend to stop backspacing at the leftmost column, hence
 213                                   * backspacing too much should be mostly OK. */
 214
 215         return backspace_chars(ttyfd, m);
 216 }
 217
 218 int ask_password_plymouth(
 219                 const char *message,
 220                 usec_t until,
 221                 AskPasswordFlags flags,
 222                 const char *flag_file,
 223                 char ***ret) {
 224
 225         static const union sockaddr_union sa = PLYMOUTH_SOCKET;
 226         _cleanup_close_ int fd = -1, notify = -1;
 227         _cleanup_free_ char *packet = NULL;
 228         ssize_t k;
 229         int r, n;
 230         struct pollfd pollfd[2] = {};
 231         char buffer[LINE_MAX];
 232         size_t p = 0;
 233         enum {
 234                 POLL_SOCKET,
 235                 POLL_INOTIFY
 236         };
 237
 238         assert(ret);
 239
 240         if (!message)
 241                 message = "Password:";
 242
 243         if (flag_file) {
 244                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 245                 if (notify < 0)
 246                         return -errno;
 247
 248                 r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
 249                 if (r < 0)
 250                         return -errno;
 251         }
 252
 253         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 254         if (fd < 0)
 255                 return -errno;
 256
 257         r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 258         if (r < 0)
 259                 return -errno;
 260
 261         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 262                 packet = strdup("c");
 263                 n = 1;
 264         } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
 265                 packet = NULL;
 266         if (!packet)
 267                 return -ENOMEM;
 268
 269         r = loop_write(fd, packet, n + 1, true);
 270         if (r < 0)
 271                 return r;
 272
 273         pollfd[POLL_SOCKET].fd = fd;
 274         pollfd[POLL_SOCKET].events = POLLIN;
 275         pollfd[POLL_INOTIFY].fd = notify;
 276         pollfd[POLL_INOTIFY].events = POLLIN;
 277
 278         for (;;) {
 279                 usec_t timeout;
 280
 281                 if (until > 0)
 282                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 283                 else
 284                         timeout = USEC_INFINITY;
 285
 286                 if (flag_file && access(flag_file, F_OK) < 0) {
 287                         r = -errno;
 288                         goto finish;
 289                 }
 290
 291                 r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
 292                 if (r == -EINTR)
 293                         continue;
 294                 if (r < 0)
 295                         goto finish;
 296                 if (r == 0) {
 297                         r = -ETIME;
 298                         goto finish;
 299                 }
 300
 301                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
 302                         (void) flush_fd(notify);
 303
 304                 if (pollfd[POLL_SOCKET].revents == 0)
 305                         continue;
 306
 307                 k = read(fd, buffer + p, sizeof(buffer) - p);
 308                 if (k < 0) {
 309                         if (IN_SET(errno, EINTR, EAGAIN))
 310                                 continue;
 311
 312                         r = -errno;
 313                         goto finish;
 314                 } else if (k == 0) {
 315                         r = -EIO;
 316                         goto finish;
 317                 }
 318
 319                 p += k;
 320
 321                 if (buffer[0] == 5) {
 322
 323                         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 324                                 /* Hmm, first try with cached
 325                                  * passwords failed, so let's retry
 326                                  * with a normal password request */
 327                                 packet = mfree(packet);
 328
 329                                 if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
 330                                         r = -ENOMEM;
 331                                         goto finish;
 332                                 }
 333
 334                                 r = loop_write(fd, packet, n+1, true);
 335                                 if (r < 0)
 336                                         goto finish;
 337
 338                                 flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
 339                                 p = 0;
 340                                 continue;
 341                         }
 342
 343                         /* No password, because UI not shown */
 344                         r = -ENOENT;
 345                         goto finish;
 346
 347                 } else if (IN_SET(buffer[0], 2, 9)) {
 348                         uint32_t size;
 349                         char **l;
 350
 351                         /* One or more answers */
 352                         if (p < 5)
 353                                 continue;
 354
 355                         memcpy(&size, buffer+1, sizeof(size));
 356                         size = le32toh(size);
 357                         if (size + 5 > sizeof(buffer)) {
 358                                 r = -EIO;
 359                                 goto finish;
 360                         }
 361
 362                         if (p-5 < size)
 363                                 continue;
 364
 365                         l = strv_parse_nulstr(buffer + 5, size);
 366                         if (!l) {
 367                                 r = -ENOMEM;
 368                                 goto finish;
 369                         }
 370
 371                         *ret = l;
 372                         break;
 373
 374                 } else {
 375                         /* Unknown packet */
 376                         r = -EIO;
 377                         goto finish;
 378                 }
 379         }
 380
 381         r = 0;
 382
 383 finish:
 384         explicit_bzero_safe(buffer, sizeof(buffer));
 385         return r;
 386 }
 387
 388 #define NO_ECHO "(no echo) "
 389 #define PRESS_TAB "(press TAB for no echo) "
 390 #define SKIPPED "(skipped)"
 391
 392 int ask_password_tty(
 393                 int ttyfd,
 394                 const char *message,
 395                 const char *keyname,
 396                 usec_t until,
 397                 AskPasswordFlags flags,
 398                 const char *flag_file,
 399                 char ***ret) {
 400
 401         enum {
 402                 POLL_TTY,
 403                 POLL_INOTIFY,
 404                 _POLL_MAX,
 405         };
 406
 407         bool reset_tty = false, dirty = false, use_color = false, press_tab_visible = false;
 408         _cleanup_close_ int cttyfd = -1, notify = -1;
 409         struct termios old_termios, new_termios;
 410         char passphrase[LINE_MAX + 1] = {}, *x;
 411         _cleanup_strv_free_erase_ char **l = NULL;
 412         struct pollfd pollfd[_POLL_MAX];
 413         size_t p = 0, codepoint = 0;
 414         int r;
 415
 416         assert(ret);
 417
 418         if (flags & ASK_PASSWORD_NO_TTY)
 419                 return -EUNATCH;
 420
 421         if (!message)
 422                 message = "Password:";
 423
 424         if (emoji_enabled())
 425                 message = strjoina(special_glyph(SPECIAL_GLYPH_LOCK_AND_KEY), " ", message);
 426
 427         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 428                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 429                 if (notify < 0)
 430                         return -errno;
 431         }
 432         if (flag_file) {
 433                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 434                         return -errno;
 435         }
 436         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 437                 r = ask_password_keyring(keyname, flags, ret);
 438                 if (r >= 0)
 439                         return 0;
 440                 else if (r != -ENOKEY)
 441                         return r;
 442
 443                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 444                         return -errno;
 445         }
 446
 447         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 448         if (ttyfd < 0)
 449                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 450
 451         if (ttyfd >= 0) {
 452                 if (tcgetattr(ttyfd, &old_termios) < 0)
 453                         return -errno;
 454
 455                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 456                         use_color = dev_console_colors_enabled();
 457                 else
 458                         use_color = colors_enabled();
 459
 460                 if (use_color)
 461                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 462
 463                 (void) loop_write(ttyfd, message, strlen(message), false);
 464                 (void) loop_write(ttyfd, " ", 1, false);
 465
 466                 if (!(flags & ASK_PASSWORD_SILENT) && !(flags & ASK_PASSWORD_ECHO)) {
 467                         if (use_color)
 468                                 (void) loop_write(ttyfd, ansi_grey(), strlen(ansi_grey()), false);
 469                         (void) loop_write(ttyfd, PRESS_TAB, strlen(PRESS_TAB), false);
 470                         press_tab_visible = true;
 471                 }
 472
 473                 if (use_color)
 474                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 475
 476                 new_termios = old_termios;
 477                 new_termios.c_lflag &= ~(ICANON|ECHO);
 478                 new_termios.c_cc[VMIN] = 1;
 479                 new_termios.c_cc[VTIME] = 0;
 480
 481                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 482                         r = -errno;
 483                         goto finish;
 484                 }
 485
 486                 reset_tty = true;
 487         }
 488
 489         pollfd[POLL_TTY] = (struct pollfd) {
 490                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 491                 .events = POLLIN,
 492         };
 493         pollfd[POLL_INOTIFY] = (struct pollfd) {
 494                 .fd = notify,
 495                 .events = POLLIN,
 496         };
 497
 498         for (;;) {
 499                 _cleanup_(erase_char) char c;
 500                 usec_t timeout;
 501                 ssize_t n;
 502
 503                 if (until > 0)
 504                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 505                 else
 506                         timeout = USEC_INFINITY;
 507
 508                 if (flag_file)
 509                         if (access(flag_file, F_OK) < 0) {
 510                                 r = -errno;
 511                                 goto finish;
 512                         }
 513
 514                 r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
 515                 if (r == -EINTR)
 516                         continue;
 517                 if (r < 0)
 518                         goto finish;
 519                 if (r == 0) {
 520                         r = -ETIME;
 521                         goto finish;
 522                 }
 523
 524                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
 525                         (void) flush_fd(notify);
 526
 527                         r = ask_password_keyring(keyname, flags, ret);
 528                         if (r >= 0) {
 529                                 r = 0;
 530                                 goto finish;
 531                         } else if (r != -ENOKEY)
 532                                 goto finish;
 533                 }
 534
 535                 if (pollfd[POLL_TTY].revents == 0)
 536                         continue;
 537
 538                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 539                 if (n < 0) {
 540                         if (IN_SET(errno, EINTR, EAGAIN))
 541                                 continue;
 542
 543                         r = -errno;
 544                         goto finish;
 545
 546                 }
 547
 548                 if (press_tab_visible) {
 549                         assert(ttyfd >= 0);
 550                         backspace_chars(ttyfd, strlen(PRESS_TAB));
 551                         press_tab_visible = false;
 552                 }
 553
 554                 /* We treat EOF, newline and NUL byte all as valid end markers */
 555                 if (n == 0 || c == '\n' || c == 0)
 556                         break;
 557
 558                 if (c == 4) { /* C-d also known as EOT */
 559                         if (ttyfd >= 0)
 560                                 (void) loop_write(ttyfd, SKIPPED, strlen(SKIPPED), false);
 561
 562                         goto skipped;
 563                 }
 564
 565                 if (c == 21) { /* C-u */
 566
 567                         if (!(flags & ASK_PASSWORD_SILENT))
 568                                 (void) backspace_string(ttyfd, passphrase);
 569
 570                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 571                         p = codepoint = 0;
 572
 573                 } else if (IN_SET(c, '\b', 127)) {
 574
 575                         if (p > 0) {
 576                                 size_t q;
 577
 578                                 if (!(flags & ASK_PASSWORD_SILENT))
 579                                         (void) backspace_chars(ttyfd, 1);
 580
 581                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 582                                  * last one begins */
 583                                 q = 0;
 584                                 for (;;) {
 585                                         int z;
 586
 587                                         z = utf8_encoded_valid_unichar(passphrase + q, SIZE_MAX);
 588                                         if (z <= 0) {
 589                                                 q = SIZE_MAX; /* Invalid UTF8! */
 590                                                 break;
 591                                         }
 592
 593                                         if (q + z >= p) /* This one brings us over the edge */
 594                                                 break;
 595
 596                                         q += z;
 597                                 }
 598
 599                                 p = codepoint = q == SIZE_MAX ? p - 1 : q;
 600                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 601
 602                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 603
 604                                 flags |= ASK_PASSWORD_SILENT;
 605
 606                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 607                                  * first key (and only as first key), or ... */
 608
 609                                 if (ttyfd >= 0)
 610                                         (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 611
 612                         } else if (ttyfd >= 0)
 613                                 (void) loop_write(ttyfd, "\a", 1, false);
 614
 615                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 616
 617                         (void) backspace_string(ttyfd, passphrase);
 618                         flags |= ASK_PASSWORD_SILENT;
 619
 620                         /* ... or by pressing TAB at any time. */
 621
 622                         if (ttyfd >= 0)
 623                                 (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 624
 625                 } else if (p >= sizeof(passphrase)-1) {
 626
 627                         /* Reached the size limit */
 628                         if (ttyfd >= 0)
 629                                 (void) loop_write(ttyfd, "\a", 1, false);
 630
 631                 } else {
 632                         passphrase[p++] = c;
 633
 634                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 635                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 636                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, SIZE_MAX);
 637                                 if (n >= 0) {
 638                                         if (flags & ASK_PASSWORD_ECHO)
 639                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 640                                         else
 641                                                 (void) loop_write(ttyfd, "*", 1, false);
 642                                         codepoint = p;
 643                                 }
 644                         }
 645
 646                         dirty = true;
 647                 }
 648         }
 649
 650         x = strndup(passphrase, p);
 651         explicit_bzero_safe(passphrase, sizeof(passphrase));
 652         if (!x) {
 653                 r = -ENOMEM;
 654                 goto finish;
 655         }
 656
 657         r = strv_consume(&l, x);
 658         if (r < 0)
 659                 goto finish;
 660
 661 skipped:
 662         if (strv_isempty(l))
 663                 r = log_debug_errno(SYNTHETIC_ERRNO(ECANCELED), "Password query was cancelled.");
 664         else {
 665                 if (keyname)
 666                         (void) add_to_keyring_and_log(keyname, flags, l);
 667
 668                 *ret = TAKE_PTR(l);
 669                 r = 0;
 670         }
 671
 672 finish:
 673         if (ttyfd >= 0 && reset_tty) {
 674                 (void) loop_write(ttyfd, "\n", 1, false);
 675                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 676         }
 677
 678         return r;
 679 }
 680
 681 static int create_socket(char **ret) {
 682         _cleanup_free_ char *path = NULL;
 683         union sockaddr_union sa;
 684         socklen_t sa_len;
 685         _cleanup_close_ int fd = -1;
 686         int r;
 687
 688         assert(ret);
 689
 690         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 691         if (fd < 0)
 692                 return -errno;
 693
 694         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 695                 return -ENOMEM;
 696
 697         r = sockaddr_un_set_path(&sa.un, path);
 698         if (r < 0)
 699                 return r;
 700         sa_len = r;
 701
 702         RUN_WITH_UMASK(0177)
 703                 if (bind(fd, &sa.sa, sa_len) < 0)
 704                         return -errno;
 705
 706         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 707         if (r < 0)
 708                 return r;
 709
 710         *ret = TAKE_PTR(path);
 711         return TAKE_FD(fd);
 712 }
 713
 714 int ask_password_agent(
 715                 const char *message,
 716                 const char *icon,
 717                 const char *id,
 718                 const char *keyname,
 719                 usec_t until,
 720                 AskPasswordFlags flags,
 721                 char ***ret) {
 722
 723         enum {
 724                 FD_SOCKET,
 725                 FD_SIGNAL,
 726                 FD_INOTIFY,
 727                 _FD_MAX
 728         };
 729
 730         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 731         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 732         char final[sizeof(temp)] = "";
 733         _cleanup_free_ char *socket_name = NULL;
 734         _cleanup_strv_free_erase_ char **l = NULL;
 735         _cleanup_fclose_ FILE *f = NULL;
 736         struct pollfd pollfd[_FD_MAX];
 737         sigset_t mask, oldmask;
 738         int r;
 739
 740         assert(ret);
 741
 742         if (flags & ASK_PASSWORD_NO_AGENT)
 743                 return -EUNATCH;
 744
 745         assert_se(sigemptyset(&mask) >= 0);
 746         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 747         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 748
 749         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 750
 751         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 752                 r = ask_password_keyring(keyname, flags, ret);
 753                 if (r >= 0) {
 754                         r = 0;
 755                         goto finish;
 756                 } else if (r != -ENOKEY)
 757                         goto finish;
 758
 759                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 760                 if (notify < 0) {
 761                         r = -errno;
 762                         goto finish;
 763                 }
 764                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 765                         r = -errno;
 766                         goto finish;
 767                 }
 768         }
 769
 770         fd = mkostemp_safe(temp);
 771         if (fd < 0) {
 772                 r = fd;
 773                 goto finish;
 774         }
 775
 776         (void) fchmod(fd, 0644);
 777
 778         f = take_fdopen(&fd, "w");
 779         if (!f) {
 780                 r = -errno;
 781                 goto finish;
 782         }
 783
 784         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 785         if (signal_fd < 0) {
 786                 r = -errno;
 787                 goto finish;
 788         }
 789
 790         socket_fd = create_socket(&socket_name);
 791         if (socket_fd < 0) {
 792                 r = socket_fd;
 793                 goto finish;
 794         }
 795
 796         fprintf(f,
 797                 "[Ask]\n"
 798                 "PID="PID_FMT"\n"
 799                 "Socket=%s\n"
 800                 "AcceptCached=%i\n"
 801                 "Echo=%i\n"
 802                 "NotAfter="USEC_FMT"\n",
 803                 getpid_cached(),
 804                 socket_name,
 805                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 806                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 807                 until);
 808
 809         if (message)
 810                 fprintf(f, "Message=%s\n", message);
 811
 812         if (icon)
 813                 fprintf(f, "Icon=%s\n", icon);
 814
 815         if (id)
 816                 fprintf(f, "Id=%s\n", id);
 817
 818         r = fflush_and_check(f);
 819         if (r < 0)
 820                 goto finish;
 821
 822         memcpy(final, temp, sizeof(temp));
 823
 824         final[sizeof(final)-11] = 'a';
 825         final[sizeof(final)-10] = 's';
 826         final[sizeof(final)-9] = 'k';
 827
 828         if (rename(temp, final) < 0) {
 829                 r = -errno;
 830                 goto finish;
 831         }
 832
 833         zero(pollfd);
 834         pollfd[FD_SOCKET].fd = socket_fd;
 835         pollfd[FD_SOCKET].events = POLLIN;
 836         pollfd[FD_SIGNAL].fd = signal_fd;
 837         pollfd[FD_SIGNAL].events = POLLIN;
 838         pollfd[FD_INOTIFY].fd = notify;
 839         pollfd[FD_INOTIFY].events = POLLIN;
 840
 841         for (;;) {
 842                 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
 843                 char passphrase[LINE_MAX+1];
 844                 struct iovec iovec;
 845                 struct ucred *ucred;
 846                 usec_t timeout;
 847                 ssize_t n;
 848
 849                 if (until > 0)
 850                         timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
 851                 else
 852                         timeout = USEC_INFINITY;
 853
 854                 r = ppoll_usec(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, timeout);
 855                 if (r == -EINTR)
 856                         continue;
 857                 if (r < 0)
 858                         goto finish;
 859                 if (r == 0) {
 860                         r = -ETIME;
 861                         goto finish;
 862                 }
 863
 864                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 865                         r = -EINTR;
 866                         goto finish;
 867                 }
 868
 869                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 870                         (void) flush_fd(notify);
 871
 872                         r = ask_password_keyring(keyname, flags, ret);
 873                         if (r >= 0) {
 874                                 r = 0;
 875                                 goto finish;
 876                         } else if (r != -ENOKEY)
 877                                 goto finish;
 878                 }
 879
 880                 if (pollfd[FD_SOCKET].revents == 0)
 881                         continue;
 882
 883                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 884                         r = -EIO;
 885                         goto finish;
 886                 }
 887
 888                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 889
 890                 struct msghdr msghdr = {
 891                         .msg_iov = &iovec,
 892                         .msg_iovlen = 1,
 893                         .msg_control = &control,
 894                         .msg_controllen = sizeof(control),
 895                 };
 896
 897                 n = recvmsg_safe(socket_fd, &msghdr, 0);
 898                 if (IN_SET(n, -EAGAIN, -EINTR))
 899                         continue;
 900                 if (n == -EXFULL) {
 901                         log_debug("Got message with truncated control data, ignoring.");
 902                         continue;
 903                 }
 904                 if (n < 0) {
 905                         r = (int) n;
 906                         goto finish;
 907                 }
 908
 909                 cmsg_close_all(&msghdr);
 910
 911                 if (n <= 0) {
 912                         log_debug("Message too short");
 913                         continue;
 914                 }
 915
 916                 ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
 917                 if (!ucred) {
 918                         log_debug("Received message without credentials. Ignoring.");
 919                         continue;
 920                 }
 921
 922                 if (ucred->uid != 0) {
 923                         log_debug("Got request from unprivileged user. Ignoring.");
 924                         continue;
 925                 }
 926
 927                 if (passphrase[0] == '+') {
 928                         /* An empty message refers to the empty password */
 929                         if (n == 1)
 930                                 l = strv_new("");
 931                         else
 932                                 l = strv_parse_nulstr(passphrase+1, n-1);
 933                         explicit_bzero_safe(passphrase, n);
 934                         if (!l) {
 935                                 r = -ENOMEM;
 936                                 goto finish;
 937                         }
 938
 939                         if (strv_isempty(l)) {
 940                                 l = strv_free(l);
 941                                 log_debug("Invalid packet");
 942                                 continue;
 943                         }
 944
 945                         break;
 946                 }
 947
 948                 if (passphrase[0] == '-') {
 949                         r = -ECANCELED;
 950                         goto finish;
 951                 }
 952
 953                 log_debug("Invalid packet");
 954         }
 955
 956         if (keyname)
 957                 (void) add_to_keyring_and_log(keyname, flags, l);
 958
 959         *ret = TAKE_PTR(l);
 960         r = 0;
 961
 962 finish:
 963         if (socket_name)
 964                 (void) unlink(socket_name);
 965
 966         (void) unlink(temp);
 967
 968         if (final[0])
 969                 (void) unlink(final);
 970
 971         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 972         return r;
 973 }
 974
 975 static int ask_password_credential(const char *credential_name, AskPasswordFlags flags, char ***ret) {
 976         _cleanup_(erase_and_freep) char *buffer = NULL;
 977         size_t size;
 978         char **l;
 979         int r;
 980
 981         assert(credential_name);
 982         assert(ret);
 983
 984         r = read_credential(credential_name, (void**) &buffer, &size);
 985         if (IN_SET(r, -ENXIO, -ENOENT)) /* No credentials passed or this credential not defined? */
 986                 return -ENOKEY;
 987
 988         l = strv_parse_nulstr(buffer, size);
 989         if (!l)
 990                 return -ENOMEM;
 991
 992         *ret = l;
 993         return 0;
 994 }
 995
 996 int ask_password_auto(
 997                 const char *message,
 998                 const char *icon,
 999                 const char *id,                /* id in "ask-password" protocol */
1000                 const char *key_name,          /* name in kernel keyring */
1001                 const char *credential_name,   /* name in $CREDENTIALS_DIRECTORY directory */
1002                 usec_t until,
1003                 AskPasswordFlags flags,
1004                 char ***ret) {
1005
1006         int r;
1007
1008         assert(ret);
1009
1010         if (!(flags & ASK_PASSWORD_NO_CREDENTIAL) && credential_name) {
1011                 r = ask_password_credential(credential_name, flags, ret);
1012                 if (r != -ENOKEY)
1013                         return r;
1014         }
1015
1016         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
1017             key_name &&
1018             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
1019             (flags & ASK_PASSWORD_NO_AGENT)) {
1020                 r = ask_password_keyring(key_name, flags, ret);
1021                 if (r != -ENOKEY)
1022                         return r;
1023         }
1024
1025         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
1026                 return ask_password_tty(-1, message, key_name, until, flags, NULL, ret);
1027
1028         if (!(flags & ASK_PASSWORD_NO_AGENT))
1029                 return ask_password_agent(message, icon, id, key_name, until, flags, ret);
1030
1031         return -EUNATCH;
1032 }