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 <poll.h>
   8 #include <stdbool.h>
   9 #include <stddef.h>
  10 #include <stdint.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <sys/inotify.h>
  14 #include <sys/signalfd.h>
  15 #include <sys/stat.h>
  16 #include <sys/time.h>
  17 #include <sys/uio.h>
  18 #include <sys/un.h>
  19 #include <termios.h>
  20 #include <unistd.h>
  21
  22 #include "alloc-util.h"
  23 #include "ask-password-api.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_t) -1)
 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                 int sleep_for = -1, j;
 280
 281                 if (until > 0) {
 282                         usec_t y;
 283
 284                         y = now(CLOCK_MONOTONIC);
 285
 286                         if (y > until) {
 287                                 r = -ETIME;
 288                                 goto finish;
 289                         }
 290
 291                         sleep_for = (int) ((until - y) / USEC_PER_MSEC);
 292                 }
 293
 294                 if (flag_file && access(flag_file, F_OK) < 0) {
 295                         r = -errno;
 296                         goto finish;
 297                 }
 298
 299                 j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 300                 if (j < 0) {
 301                         if (errno == EINTR)
 302                                 continue;
 303
 304                         r = -errno;
 305                         goto finish;
 306                 } else if (j == 0) {
 307                         r = -ETIME;
 308                         goto finish;
 309                 }
 310
 311                 if (pollfd[POLL_SOCKET].revents & POLLNVAL ||
 312                     (notify >= 0 && pollfd[POLL_INOTIFY].revents & POLLNVAL)) {
 313                         r = -EBADF;
 314                         goto finish;
 315                 }
 316
 317                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
 318                         (void) flush_fd(notify);
 319
 320                 if (pollfd[POLL_SOCKET].revents == 0)
 321                         continue;
 322
 323                 k = read(fd, buffer + p, sizeof(buffer) - p);
 324                 if (k < 0) {
 325                         if (IN_SET(errno, EINTR, EAGAIN))
 326                                 continue;
 327
 328                         r = -errno;
 329                         goto finish;
 330                 } else if (k == 0) {
 331                         r = -EIO;
 332                         goto finish;
 333                 }
 334
 335                 p += k;
 336
 337                 if (buffer[0] == 5) {
 338
 339                         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 340                                 /* Hmm, first try with cached
 341                                  * passwords failed, so let's retry
 342                                  * with a normal password request */
 343                                 packet = mfree(packet);
 344
 345                                 if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
 346                                         r = -ENOMEM;
 347                                         goto finish;
 348                                 }
 349
 350                                 r = loop_write(fd, packet, n+1, true);
 351                                 if (r < 0)
 352                                         goto finish;
 353
 354                                 flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
 355                                 p = 0;
 356                                 continue;
 357                         }
 358
 359                         /* No password, because UI not shown */
 360                         r = -ENOENT;
 361                         goto finish;
 362
 363                 } else if (IN_SET(buffer[0], 2, 9)) {
 364                         uint32_t size;
 365                         char **l;
 366
 367                         /* One or more answers */
 368                         if (p < 5)
 369                                 continue;
 370
 371                         memcpy(&size, buffer+1, sizeof(size));
 372                         size = le32toh(size);
 373                         if (size + 5 > sizeof(buffer)) {
 374                                 r = -EIO;
 375                                 goto finish;
 376                         }
 377
 378                         if (p-5 < size)
 379                                 continue;
 380
 381                         l = strv_parse_nulstr(buffer + 5, size);
 382                         if (!l) {
 383                                 r = -ENOMEM;
 384                                 goto finish;
 385                         }
 386
 387                         *ret = l;
 388                         break;
 389
 390                 } else {
 391                         /* Unknown packet */
 392                         r = -EIO;
 393                         goto finish;
 394                 }
 395         }
 396
 397         r = 0;
 398
 399 finish:
 400         explicit_bzero_safe(buffer, sizeof(buffer));
 401         return r;
 402 }
 403
 404 #define NO_ECHO "(no echo) "
 405 #define PRESS_TAB "(press TAB for no echo) "
 406 #define SKIPPED "(skipped)"
 407
 408 int ask_password_tty(
 409                 int ttyfd,
 410                 const char *message,
 411                 const char *keyname,
 412                 usec_t until,
 413                 AskPasswordFlags flags,
 414                 const char *flag_file,
 415                 char ***ret) {
 416
 417         enum {
 418                 POLL_TTY,
 419                 POLL_INOTIFY,
 420                 _POLL_MAX,
 421         };
 422
 423         bool reset_tty = false, dirty = false, use_color = false, press_tab_visible = false;
 424         _cleanup_close_ int cttyfd = -1, notify = -1;
 425         struct termios old_termios, new_termios;
 426         char passphrase[LINE_MAX + 1] = {}, *x;
 427         _cleanup_strv_free_erase_ char **l = NULL;
 428         struct pollfd pollfd[_POLL_MAX];
 429         size_t p = 0, codepoint = 0;
 430         int r;
 431
 432         assert(ret);
 433
 434         if (flags & ASK_PASSWORD_NO_TTY)
 435                 return -EUNATCH;
 436
 437         if (!message)
 438                 message = "Password:";
 439
 440         if (emoji_enabled())
 441                 message = strjoina(special_glyph(SPECIAL_GLYPH_LOCK_AND_KEY), " ", message);
 442
 443         if (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 444                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 445                 if (notify < 0)
 446                         return -errno;
 447         }
 448         if (flag_file) {
 449                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 450                         return -errno;
 451         }
 452         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 453                 r = ask_password_keyring(keyname, flags, ret);
 454                 if (r >= 0)
 455                         return 0;
 456                 else if (r != -ENOKEY)
 457                         return r;
 458
 459                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 460                         return -errno;
 461         }
 462
 463         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 464         if (ttyfd < 0)
 465                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 466
 467         if (ttyfd >= 0) {
 468                 if (tcgetattr(ttyfd, &old_termios) < 0)
 469                         return -errno;
 470
 471                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 472                         use_color = dev_console_colors_enabled();
 473                 else
 474                         use_color = colors_enabled();
 475
 476                 if (use_color)
 477                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 478
 479                 (void) loop_write(ttyfd, message, strlen(message), false);
 480                 (void) loop_write(ttyfd, " ", 1, false);
 481
 482                 if (!(flags & ASK_PASSWORD_SILENT) && !(flags & ASK_PASSWORD_ECHO)) {
 483                         if (use_color)
 484                                 (void) loop_write(ttyfd, ansi_grey(), strlen(ansi_grey()), false);
 485                         (void) loop_write(ttyfd, PRESS_TAB, strlen(PRESS_TAB), false);
 486                         press_tab_visible = true;
 487                 }
 488
 489                 if (use_color)
 490                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 491
 492                 new_termios = old_termios;
 493                 new_termios.c_lflag &= ~(ICANON|ECHO);
 494                 new_termios.c_cc[VMIN] = 1;
 495                 new_termios.c_cc[VTIME] = 0;
 496
 497                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 498                         r = -errno;
 499                         goto finish;
 500                 }
 501
 502                 reset_tty = true;
 503         }
 504
 505         pollfd[POLL_TTY] = (struct pollfd) {
 506                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 507                 .events = POLLIN,
 508         };
 509         pollfd[POLL_INOTIFY] = (struct pollfd) {
 510                 .fd = notify,
 511                 .events = POLLIN,
 512         };
 513
 514         for (;;) {
 515                 _cleanup_(erase_char) char c;
 516                 int sleep_for = -1, k;
 517                 ssize_t n;
 518
 519                 if (until > 0) {
 520                         usec_t y;
 521
 522                         y = now(CLOCK_MONOTONIC);
 523
 524                         if (y > until) {
 525                                 r = -ETIME;
 526                                 goto finish;
 527                         }
 528
 529                         sleep_for = (int) DIV_ROUND_UP(until - y, USEC_PER_MSEC);
 530                 }
 531
 532                 if (flag_file)
 533                         if (access(flag_file, F_OK) < 0) {
 534                                 r = -errno;
 535                                 goto finish;
 536                         }
 537
 538                 k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 539                 if (k < 0) {
 540                         if (errno == EINTR)
 541                                 continue;
 542
 543                         r = -errno;
 544                         goto finish;
 545                 } else if (k == 0) {
 546                         r = -ETIME;
 547                         goto finish;
 548                 }
 549
 550                 if ((pollfd[POLL_TTY].revents & POLLNVAL) ||
 551                     (notify >= 0 && (pollfd[POLL_INOTIFY].revents & POLLNVAL))) {
 552                         r = -EBADF;
 553                         goto finish;
 554                 }
 555
 556                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
 557                         (void) flush_fd(notify);
 558
 559                         r = ask_password_keyring(keyname, flags, ret);
 560                         if (r >= 0) {
 561                                 r = 0;
 562                                 goto finish;
 563                         } else if (r != -ENOKEY)
 564                                 goto finish;
 565                 }
 566
 567                 if (pollfd[POLL_TTY].revents == 0)
 568                         continue;
 569
 570                 n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
 571                 if (n < 0) {
 572                         if (IN_SET(errno, EINTR, EAGAIN))
 573                                 continue;
 574
 575                         r = -errno;
 576                         goto finish;
 577
 578                 }
 579
 580                 if (press_tab_visible) {
 581                         assert(ttyfd >= 0);
 582                         backspace_chars(ttyfd, strlen(PRESS_TAB));
 583                         press_tab_visible = false;
 584                 }
 585
 586                 /* We treat EOF, newline and NUL byte all as valid end markers */
 587                 if (n == 0 || c == '\n' || c == 0)
 588                         break;
 589
 590                 if (c == 4) { /* C-d also known as EOT */
 591                         if (ttyfd >= 0)
 592                                 (void) loop_write(ttyfd, SKIPPED, strlen(SKIPPED), false);
 593
 594                         goto skipped;
 595                 }
 596
 597                 if (c == 21) { /* C-u */
 598
 599                         if (!(flags & ASK_PASSWORD_SILENT))
 600                                 (void) backspace_string(ttyfd, passphrase);
 601
 602                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 603                         p = codepoint = 0;
 604
 605                 } else if (IN_SET(c, '\b', 127)) {
 606
 607                         if (p > 0) {
 608                                 size_t q;
 609
 610                                 if (!(flags & ASK_PASSWORD_SILENT))
 611                                         (void) backspace_chars(ttyfd, 1);
 612
 613                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 614                                  * last one begins */
 615                                 q = 0;
 616                                 for (;;) {
 617                                         size_t z;
 618
 619                                         z = utf8_encoded_valid_unichar(passphrase + q, (size_t) -1);
 620                                         if (z == 0) {
 621                                                 q = (size_t) -1; /* Invalid UTF8! */
 622                                                 break;
 623                                         }
 624
 625                                         if (q + z >= p) /* This one brings us over the edge */
 626                                                 break;
 627
 628                                         q += z;
 629                                 }
 630
 631                                 p = codepoint = q == (size_t) -1 ? p - 1 : q;
 632                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 633
 634                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 635
 636                                 flags |= ASK_PASSWORD_SILENT;
 637
 638                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 639                                  * first key (and only as first key), or ... */
 640
 641                                 if (ttyfd >= 0)
 642                                         (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 643
 644                         } else if (ttyfd >= 0)
 645                                 (void) loop_write(ttyfd, "\a", 1, false);
 646
 647                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 648
 649                         (void) backspace_string(ttyfd, passphrase);
 650                         flags |= ASK_PASSWORD_SILENT;
 651
 652                         /* ... or by pressing TAB at any time. */
 653
 654                         if (ttyfd >= 0)
 655                                 (void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
 656
 657                 } else if (p >= sizeof(passphrase)-1) {
 658
 659                         /* Reached the size limit */
 660                         if (ttyfd >= 0)
 661                                 (void) loop_write(ttyfd, "\a", 1, false);
 662
 663                 } else {
 664                         passphrase[p++] = c;
 665
 666                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 667                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 668                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, (size_t) -1);
 669                                 if (n >= 0) {
 670                                         if (flags & ASK_PASSWORD_ECHO)
 671                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 672                                         else
 673                                                 (void) loop_write(ttyfd, "*", 1, false);
 674                                         codepoint = p;
 675                                 }
 676                         }
 677
 678                         dirty = true;
 679                 }
 680         }
 681
 682         x = strndup(passphrase, p);
 683         explicit_bzero_safe(passphrase, sizeof(passphrase));
 684         if (!x) {
 685                 r = -ENOMEM;
 686                 goto finish;
 687         }
 688
 689         r = strv_consume(&l, x);
 690         if (r < 0)
 691                 goto finish;
 692
 693 skipped:
 694         if (strv_isempty(l))
 695                 r = log_debug_errno(SYNTHETIC_ERRNO(ECANCELED), "Password query was cancelled.");
 696         else {
 697                 if (keyname)
 698                         (void) add_to_keyring_and_log(keyname, flags, l);
 699
 700                 *ret = TAKE_PTR(l);
 701                 r = 0;
 702         }
 703
 704 finish:
 705         if (ttyfd >= 0 && reset_tty) {
 706                 (void) loop_write(ttyfd, "\n", 1, false);
 707                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 708         }
 709
 710         return r;
 711 }
 712
 713 static int create_socket(char **ret) {
 714         _cleanup_free_ char *path = NULL;
 715         union sockaddr_union sa;
 716         socklen_t sa_len;
 717         _cleanup_close_ int fd = -1;
 718         int r;
 719
 720         assert(ret);
 721
 722         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 723         if (fd < 0)
 724                 return -errno;
 725
 726         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 727                 return -ENOMEM;
 728
 729         r = sockaddr_un_set_path(&sa.un, path);
 730         if (r < 0)
 731                 return r;
 732         sa_len = r;
 733
 734         RUN_WITH_UMASK(0177)
 735                 if (bind(fd, &sa.sa, sa_len) < 0)
 736                         return -errno;
 737
 738         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 739         if (r < 0)
 740                 return r;
 741
 742         *ret = TAKE_PTR(path);
 743         return TAKE_FD(fd);
 744 }
 745
 746 int ask_password_agent(
 747                 const char *message,
 748                 const char *icon,
 749                 const char *id,
 750                 const char *keyname,
 751                 usec_t until,
 752                 AskPasswordFlags flags,
 753                 char ***ret) {
 754
 755         enum {
 756                 FD_SOCKET,
 757                 FD_SIGNAL,
 758                 FD_INOTIFY,
 759                 _FD_MAX
 760         };
 761
 762         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 763         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 764         char final[sizeof(temp)] = "";
 765         _cleanup_free_ char *socket_name = NULL;
 766         _cleanup_strv_free_erase_ char **l = NULL;
 767         _cleanup_fclose_ FILE *f = NULL;
 768         struct pollfd pollfd[_FD_MAX];
 769         sigset_t mask, oldmask;
 770         int r;
 771
 772         assert(ret);
 773
 774         if (flags & ASK_PASSWORD_NO_AGENT)
 775                 return -EUNATCH;
 776
 777         assert_se(sigemptyset(&mask) >= 0);
 778         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 779         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 780
 781         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 782
 783         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 784                 r = ask_password_keyring(keyname, flags, ret);
 785                 if (r >= 0) {
 786                         r = 0;
 787                         goto finish;
 788                 } else if (r != -ENOKEY)
 789                         goto finish;
 790
 791                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 792                 if (notify < 0) {
 793                         r = -errno;
 794                         goto finish;
 795                 }
 796                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 797                         r = -errno;
 798                         goto finish;
 799                 }
 800         }
 801
 802         fd = mkostemp_safe(temp);
 803         if (fd < 0) {
 804                 r = fd;
 805                 goto finish;
 806         }
 807
 808         (void) fchmod(fd, 0644);
 809
 810         f = take_fdopen(&fd, "w");
 811         if (!f) {
 812                 r = -errno;
 813                 goto finish;
 814         }
 815
 816         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 817         if (signal_fd < 0) {
 818                 r = -errno;
 819                 goto finish;
 820         }
 821
 822         socket_fd = create_socket(&socket_name);
 823         if (socket_fd < 0) {
 824                 r = socket_fd;
 825                 goto finish;
 826         }
 827
 828         fprintf(f,
 829                 "[Ask]\n"
 830                 "PID="PID_FMT"\n"
 831                 "Socket=%s\n"
 832                 "AcceptCached=%i\n"
 833                 "Echo=%i\n"
 834                 "NotAfter="USEC_FMT"\n",
 835                 getpid_cached(),
 836                 socket_name,
 837                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 838                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 839                 until);
 840
 841         if (message)
 842                 fprintf(f, "Message=%s\n", message);
 843
 844         if (icon)
 845                 fprintf(f, "Icon=%s\n", icon);
 846
 847         if (id)
 848                 fprintf(f, "Id=%s\n", id);
 849
 850         r = fflush_and_check(f);
 851         if (r < 0)
 852                 goto finish;
 853
 854         memcpy(final, temp, sizeof(temp));
 855
 856         final[sizeof(final)-11] = 'a';
 857         final[sizeof(final)-10] = 's';
 858         final[sizeof(final)-9] = 'k';
 859
 860         if (rename(temp, final) < 0) {
 861                 r = -errno;
 862                 goto finish;
 863         }
 864
 865         zero(pollfd);
 866         pollfd[FD_SOCKET].fd = socket_fd;
 867         pollfd[FD_SOCKET].events = POLLIN;
 868         pollfd[FD_SIGNAL].fd = signal_fd;
 869         pollfd[FD_SIGNAL].events = POLLIN;
 870         pollfd[FD_INOTIFY].fd = notify;
 871         pollfd[FD_INOTIFY].events = POLLIN;
 872
 873         for (;;) {
 874                 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
 875                 char passphrase[LINE_MAX+1];
 876                 struct iovec iovec;
 877                 struct ucred *ucred;
 878                 ssize_t n;
 879                 int k;
 880                 usec_t t;
 881
 882                 t = now(CLOCK_MONOTONIC);
 883
 884                 if (until > 0 && until <= t) {
 885                         r = -ETIME;
 886                         goto finish;
 887                 }
 888
 889                 k = poll(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1);
 890                 if (k < 0) {
 891                         if (errno == EINTR)
 892                                 continue;
 893
 894                         r = -errno;
 895                         goto finish;
 896                 }
 897
 898                 if (k <= 0) {
 899                         r = -ETIME;
 900                         goto finish;
 901                 }
 902
 903                 if (pollfd[FD_SOCKET].revents & POLLNVAL ||
 904                     pollfd[FD_SIGNAL].revents & POLLNVAL ||
 905                     (notify >= 0 && pollfd[FD_INOTIFY].revents & POLLNVAL)) {
 906                         r = -EBADF;
 907                         goto finish;
 908                 }
 909
 910                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 911                         r = -EINTR;
 912                         goto finish;
 913                 }
 914
 915                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 916                         (void) flush_fd(notify);
 917
 918                         r = ask_password_keyring(keyname, flags, ret);
 919                         if (r >= 0) {
 920                                 r = 0;
 921                                 goto finish;
 922                         } else if (r != -ENOKEY)
 923                                 goto finish;
 924                 }
 925
 926                 if (pollfd[FD_SOCKET].revents == 0)
 927                         continue;
 928
 929                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 930                         r = -EIO;
 931                         goto finish;
 932                 }
 933
 934                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 935
 936                 struct msghdr msghdr = {
 937                         .msg_iov = &iovec,
 938                         .msg_iovlen = 1,
 939                         .msg_control = &control,
 940                         .msg_controllen = sizeof(control),
 941                 };
 942
 943                 n = recvmsg_safe(socket_fd, &msghdr, 0);
 944                 if (IN_SET(n, -EAGAIN, -EINTR))
 945                         continue;
 946                 if (n < 0) {
 947                         r = (int) n;
 948                         goto finish;
 949                 }
 950
 951                 cmsg_close_all(&msghdr);
 952
 953                 if (n <= 0) {
 954                         log_debug("Message too short");
 955                         continue;
 956                 }
 957
 958                 ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
 959                 if (!ucred) {
 960                         log_debug("Received message without credentials. Ignoring.");
 961                         continue;
 962                 }
 963
 964                 if (ucred->uid != 0) {
 965                         log_debug("Got request from unprivileged user. Ignoring.");
 966                         continue;
 967                 }
 968
 969                 if (passphrase[0] == '+') {
 970                         /* An empty message refers to the empty password */
 971                         if (n == 1)
 972                                 l = strv_new("");
 973                         else
 974                                 l = strv_parse_nulstr(passphrase+1, n-1);
 975                         explicit_bzero_safe(passphrase, n);
 976                         if (!l) {
 977                                 r = -ENOMEM;
 978                                 goto finish;
 979                         }
 980
 981                         if (strv_isempty(l)) {
 982                                 l = strv_free(l);
 983                                 log_debug("Invalid packet");
 984                                 continue;
 985                         }
 986
 987                         break;
 988                 }
 989
 990                 if (passphrase[0] == '-') {
 991                         r = -ECANCELED;
 992                         goto finish;
 993                 }
 994
 995                 log_debug("Invalid packet");
 996         }
 997
 998         if (keyname)
 999                 (void) add_to_keyring_and_log(keyname, flags, l);
1000
1001         *ret = TAKE_PTR(l);
1002         r = 0;
1003
1004 finish:
1005         if (socket_name)
1006                 (void) unlink(socket_name);
1007
1008         (void) unlink(temp);
1009
1010         if (final[0])
1011                 (void) unlink(final);
1012
1013         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
1014         return r;
1015 }
1016
1017 int ask_password_auto(
1018                 const char *message,
1019                 const char *icon,
1020                 const char *id,
1021                 const char *keyname,
1022                 usec_t until,
1023                 AskPasswordFlags flags,
1024                 char ***ret) {
1025
1026         int r;
1027
1028         assert(ret);
1029
1030         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
1031             keyname &&
1032             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
1033             (flags & ASK_PASSWORD_NO_AGENT)) {
1034                 r = ask_password_keyring(keyname, flags, ret);
1035                 if (r != -ENOKEY)
1036                         return r;
1037         }
1038
1039         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
1040                 return ask_password_tty(-1, message, keyname, until, flags, NULL, ret);
1041
1042         if (!(flags & ASK_PASSWORD_NO_AGENT))
1043                 return ask_password_agent(message, icon, id, keyname, until, flags, ret);
1044
1045         return -EUNATCH;
1046 }