src/shared/ask-password-api.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 "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         assert(passwords);
 109
 110         if (!(flags & ASK_PASSWORD_PUSH_CACHE))
 111                 return 0;
 112
 113         r = lookup_key(keyname, &serial);
 114         if (r >= 0) {
 115                 r = retrieve_key(serial, &l);
 116                 if (r < 0)
 117                         return r;
 118         } else if (r != -ENOKEY)
 119                 return r;
 120
 121         r = strv_extend_strv(&l, passwords, true);
 122         if (r <= 0)
 123                 return r;
 124
 125         r = strv_make_nulstr(l, &p, &n);
 126         if (r < 0)
 127                 return r;
 128
 129         serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
 130         if (serial == -1)
 131                 return -errno;
 132
 133         if (keyctl(KEYCTL_SET_TIMEOUT,
 134                    (unsigned long) serial,
 135                    (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0)
 136                 log_debug_errno(errno, "Failed to adjust timeout: %m");
 137
 138         /* Tell everyone to check the keyring */
 139         (void) touch("/run/systemd/ask-password");
 140
 141         log_debug("Added key to keyring as %" PRIi32 ".", serial);
 142
 143         return 1;
 144 }
 145
 146 static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
 147         int r;
 148
 149         assert(keyname);
 150         assert(passwords);
 151
 152         r = add_to_keyring(keyname, flags, passwords);
 153         if (r < 0)
 154                 return log_debug_errno(r, "Failed to add password to 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 (r == -ENOSYS) /* when retrieving the distinction doesn't matter */
 172                 return -ENOKEY;
 173         if (r < 0)
 174                 return r;
 175
 176         return retrieve_key(serial, ret);
 177 }
 178
 179 static int backspace_chars(int ttyfd, size_t p) {
 180         if (ttyfd < 0)
 181                 return 0;
 182
 183         _cleanup_free_ char *buf = malloc_multiply(3, p);
 184         if (!buf)
 185                 return log_oom();
 186
 187         for (size_t i = 0; i < p; i++)
 188                 memcpy(buf + 3 * i, "\b \b", 3);
 189
 190         return loop_write(ttyfd, buf, 3*p, false);
 191 }
 192
 193 static int backspace_string(int ttyfd, const char *str) {
 194         assert(str);
 195
 196         /* Backspaces through enough characters to entirely undo printing of the specified string. */
 197
 198         if (ttyfd < 0)
 199                 return 0;
 200
 201         size_t m = utf8_n_codepoints(str);
 202         if (m == (size_t) -1)
 203                 m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes
 204                                   * output. Most likely this happened because we are not in an UTF-8 locale,
 205                                   * and in that case that is the correct thing to do. And even if it's not,
 206                                   * terminals tend to stop backspacing at the leftmost column, hence
 207                                   * backspacing too much should be mostly OK. */
 208
 209         return backspace_chars(ttyfd, m);
 210 }
 211
 212 int ask_password_plymouth(
 213                 const char *message,
 214                 usec_t until,
 215                 AskPasswordFlags flags,
 216                 const char *flag_file,
 217                 char ***ret) {
 218
 219         static const union sockaddr_union sa = PLYMOUTH_SOCKET;
 220         _cleanup_close_ int fd = -1, notify = -1;
 221         _cleanup_free_ char *packet = NULL;
 222         ssize_t k;
 223         int r, n;
 224         struct pollfd pollfd[2] = {};
 225         char buffer[LINE_MAX];
 226         size_t p = 0;
 227         enum {
 228                 POLL_SOCKET,
 229                 POLL_INOTIFY
 230         };
 231
 232         assert(ret);
 233
 234         if (flag_file) {
 235                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 236                 if (notify < 0)
 237                         return -errno;
 238
 239                 r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
 240                 if (r < 0)
 241                         return -errno;
 242         }
 243
 244         fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 245         if (fd < 0)
 246                 return -errno;
 247
 248         r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
 249         if (r < 0)
 250                 return -errno;
 251
 252         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 253                 packet = strdup("c");
 254                 n = 1;
 255         } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
 256                 packet = NULL;
 257         if (!packet)
 258                 return -ENOMEM;
 259
 260         r = loop_write(fd, packet, n + 1, true);
 261         if (r < 0)
 262                 return r;
 263
 264         pollfd[POLL_SOCKET].fd = fd;
 265         pollfd[POLL_SOCKET].events = POLLIN;
 266         pollfd[POLL_INOTIFY].fd = notify;
 267         pollfd[POLL_INOTIFY].events = POLLIN;
 268
 269         for (;;) {
 270                 int sleep_for = -1, j;
 271
 272                 if (until > 0) {
 273                         usec_t y;
 274
 275                         y = now(CLOCK_MONOTONIC);
 276
 277                         if (y > until) {
 278                                 r = -ETIME;
 279                                 goto finish;
 280                         }
 281
 282                         sleep_for = (int) ((until - y) / USEC_PER_MSEC);
 283                 }
 284
 285                 if (flag_file && access(flag_file, F_OK) < 0) {
 286                         r = -errno;
 287                         goto finish;
 288                 }
 289
 290                 j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 291                 if (j < 0) {
 292                         if (errno == EINTR)
 293                                 continue;
 294
 295                         r = -errno;
 296                         goto finish;
 297                 } else if (j == 0) {
 298                         r = -ETIME;
 299                         goto finish;
 300                 }
 301
 302                 if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
 303                         (void) flush_fd(notify);
 304
 305                 if (pollfd[POLL_SOCKET].revents == 0)
 306                         continue;
 307
 308                 k = read(fd, buffer + p, sizeof(buffer) - p);
 309                 if (k < 0) {
 310                         if (IN_SET(errno, EINTR, EAGAIN))
 311                                 continue;
 312
 313                         r = -errno;
 314                         goto finish;
 315                 } else if (k == 0) {
 316                         r = -EIO;
 317                         goto finish;
 318                 }
 319
 320                 p += k;
 321
 322                 if (p < 1)
 323                         continue;
 324
 325                 if (buffer[0] == 5) {
 326
 327                         if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
 328                                 /* Hmm, first try with cached
 329                                  * passwords failed, so let's retry
 330                                  * with a normal password request */
 331                                 packet = mfree(packet);
 332
 333                                 if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
 334                                         r = -ENOMEM;
 335                                         goto finish;
 336                                 }
 337
 338                                 r = loop_write(fd, packet, n+1, true);
 339                                 if (r < 0)
 340                                         goto finish;
 341
 342                                 flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
 343                                 p = 0;
 344                                 continue;
 345                         }
 346
 347                         /* No password, because UI not shown */
 348                         r = -ENOENT;
 349                         goto finish;
 350
 351                 } else if (IN_SET(buffer[0], 2, 9)) {
 352                         uint32_t size;
 353                         char **l;
 354
 355                         /* One or more answers */
 356                         if (p < 5)
 357                                 continue;
 358
 359                         memcpy(&size, buffer+1, sizeof(size));
 360                         size = le32toh(size);
 361                         if (size + 5 > sizeof(buffer)) {
 362                                 r = -EIO;
 363                                 goto finish;
 364                         }
 365
 366                         if (p-5 < size)
 367                                 continue;
 368
 369                         l = strv_parse_nulstr(buffer + 5, size);
 370                         if (!l) {
 371                                 r = -ENOMEM;
 372                                 goto finish;
 373                         }
 374
 375                         *ret = l;
 376                         break;
 377
 378                 } else {
 379                         /* Unknown packet */
 380                         r = -EIO;
 381                         goto finish;
 382                 }
 383         }
 384
 385         r = 0;
 386
 387 finish:
 388         explicit_bzero_safe(buffer, sizeof(buffer));
 389         return r;
 390 }
 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;
 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 (flag_file || ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
 425                 notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
 426                 if (notify < 0)
 427                         return -errno;
 428         }
 429         if (flag_file) {
 430                 if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
 431                         return -errno;
 432         }
 433         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 434                 r = ask_password_keyring(keyname, flags, ret);
 435                 if (r >= 0)
 436                         return 0;
 437                 else if (r != -ENOKEY)
 438                         return r;
 439
 440                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
 441                         return -errno;
 442         }
 443
 444         /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
 445         if (ttyfd < 0)
 446                 ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
 447
 448         if (ttyfd >= 0) {
 449                 if (tcgetattr(ttyfd, &old_termios) < 0)
 450                         return -errno;
 451
 452                 if (flags & ASK_PASSWORD_CONSOLE_COLOR)
 453                         use_color = dev_console_colors_enabled();
 454                 else
 455                         use_color = colors_enabled();
 456
 457                 if (use_color)
 458                         (void) loop_write(ttyfd, ANSI_HIGHLIGHT, STRLEN(ANSI_HIGHLIGHT), false);
 459
 460                 (void) loop_write(ttyfd, message, strlen(message), false);
 461                 (void) loop_write(ttyfd, " ", 1, false);
 462
 463                 if (use_color)
 464                         (void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
 465
 466                 new_termios = old_termios;
 467                 new_termios.c_lflag &= ~(ICANON|ECHO);
 468                 new_termios.c_cc[VMIN] = 1;
 469                 new_termios.c_cc[VTIME] = 0;
 470
 471                 if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) {
 472                         r = -errno;
 473                         goto finish;
 474                 }
 475
 476                 reset_tty = true;
 477         }
 478
 479         pollfd[POLL_TTY] = (struct pollfd) {
 480                 .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
 481                 .events = POLLIN,
 482         };
 483         pollfd[POLL_INOTIFY] = (struct pollfd) {
 484                 .fd = notify,
 485                 .events = POLLIN,
 486         };
 487
 488         for (;;) {
 489                 _cleanup_(erase_char) char c;
 490                 int sleep_for = -1, k;
 491                 ssize_t n;
 492
 493                 if (until > 0) {
 494                         usec_t y;
 495
 496                         y = now(CLOCK_MONOTONIC);
 497
 498                         if (y > until) {
 499                                 r = -ETIME;
 500                                 goto finish;
 501                         }
 502
 503                         sleep_for = (int) DIV_ROUND_UP(until - y, USEC_PER_MSEC);
 504                 }
 505
 506                 if (flag_file)
 507                         if (access(flag_file, F_OK) < 0) {
 508                                 r = -errno;
 509                                 goto finish;
 510                         }
 511
 512                 k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
 513                 if (k < 0) {
 514                         if (errno == EINTR)
 515                                 continue;
 516
 517                         r = -errno;
 518                         goto finish;
 519                 } else if (k == 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                 /* We treat EOF, newline and NUL byte all as valid end markers */
 549                 if (n == 0 || c == '\n' || c == 0)
 550                         break;
 551
 552                 if (c == 4) { /* C-d also known as EOT */
 553                         if (ttyfd >= 0)
 554                                 (void) loop_write(ttyfd, "(skipped)", 9, false);
 555
 556                         goto skipped;
 557                 }
 558
 559                 if (c == 21) { /* C-u */
 560
 561                         if (!(flags & ASK_PASSWORD_SILENT))
 562                                 (void) backspace_string(ttyfd, passphrase);
 563
 564                         explicit_bzero_safe(passphrase, sizeof(passphrase));
 565                         p = codepoint = 0;
 566
 567                 } else if (IN_SET(c, '\b', 127)) {
 568
 569                         if (p > 0) {
 570                                 size_t q;
 571
 572                                 if (!(flags & ASK_PASSWORD_SILENT))
 573                                         (void) backspace_chars(ttyfd, 1);
 574
 575                                 /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
 576                                  * last one begins */
 577                                 q = 0;
 578                                 for (;;) {
 579                                         size_t z;
 580
 581                                         z = utf8_encoded_valid_unichar(passphrase + q, (size_t) -1);
 582                                         if (z == 0) {
 583                                                 q = (size_t) -1; /* Invalid UTF8! */
 584                                                 break;
 585                                         }
 586
 587                                         if (q + z >= p) /* This one brings us over the edge */
 588                                                 break;
 589
 590                                         q += z;
 591                                 }
 592
 593                                 p = codepoint = q == (size_t) -1 ? p - 1 : q;
 594                                 explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
 595
 596                         } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) {
 597
 598                                 flags |= ASK_PASSWORD_SILENT;
 599
 600                                 /* There are two ways to enter silent mode. Either by pressing backspace as
 601                                  * first key (and only as first key), or ... */
 602
 603                                 if (ttyfd >= 0)
 604                                         (void) loop_write(ttyfd, "(no echo) ", 10, false);
 605
 606                         } else if (ttyfd >= 0)
 607                                 (void) loop_write(ttyfd, "\a", 1, false);
 608
 609                 } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) {
 610
 611                         (void) backspace_string(ttyfd, passphrase);
 612                         flags |= ASK_PASSWORD_SILENT;
 613
 614                         /* ... or by pressing TAB at any time. */
 615
 616                         if (ttyfd >= 0)
 617                                 (void) loop_write(ttyfd, "(no echo) ", 10, false);
 618
 619                 } else if (p >= sizeof(passphrase)-1) {
 620
 621                         /* Reached the size limit */
 622                         if (ttyfd >= 0)
 623                                 (void) loop_write(ttyfd, "\a", 1, false);
 624
 625                 } else {
 626                         passphrase[p++] = c;
 627
 628                         if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) {
 629                                 /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
 630                                 n = utf8_encoded_valid_unichar(passphrase + codepoint, (size_t) -1);
 631                                 if (n >= 0) {
 632                                         if (flags & ASK_PASSWORD_ECHO)
 633                                                 (void) loop_write(ttyfd, passphrase + codepoint, n, false);
 634                                         else
 635                                                 (void) loop_write(ttyfd, "*", 1, false);
 636                                         codepoint = p;
 637                                 }
 638                         }
 639
 640                         dirty = true;
 641                 }
 642         }
 643
 644         x = strndup(passphrase, p);
 645         explicit_bzero_safe(passphrase, sizeof(passphrase));
 646         if (!x) {
 647                 r = -ENOMEM;
 648                 goto finish;
 649         }
 650
 651         r = strv_consume(&l, x);
 652         if (r < 0)
 653                 goto finish;
 654
 655 skipped:
 656         if (keyname)
 657                 (void) add_to_keyring_and_log(keyname, flags, l);
 658
 659         *ret = TAKE_PTR(l);
 660         r = 0;
 661
 662 finish:
 663         if (ttyfd >= 0 && reset_tty) {
 664                 (void) loop_write(ttyfd, "\n", 1, false);
 665                 (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
 666         }
 667
 668         return r;
 669 }
 670
 671 static int create_socket(char **ret) {
 672         _cleanup_free_ char *path = NULL;
 673         union sockaddr_union sa = {};
 674         _cleanup_close_ int fd = -1;
 675         int salen, r;
 676
 677         assert(ret);
 678
 679         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
 680         if (fd < 0)
 681                 return -errno;
 682
 683         if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
 684                 return -ENOMEM;
 685
 686         salen = sockaddr_un_set_path(&sa.un, path);
 687         if (salen < 0)
 688                 return salen;
 689
 690         RUN_WITH_UMASK(0177) {
 691                 if (bind(fd, &sa.sa, salen) < 0)
 692                         return -errno;
 693         }
 694
 695         r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
 696         if (r < 0)
 697                 return r;
 698
 699         *ret = TAKE_PTR(path);
 700         return TAKE_FD(fd);
 701 }
 702
 703 int ask_password_agent(
 704                 const char *message,
 705                 const char *icon,
 706                 const char *id,
 707                 const char *keyname,
 708                 usec_t until,
 709                 AskPasswordFlags flags,
 710                 char ***ret) {
 711
 712         enum {
 713                 FD_SOCKET,
 714                 FD_SIGNAL,
 715                 FD_INOTIFY,
 716                 _FD_MAX
 717         };
 718
 719         _cleanup_close_ int socket_fd = -1, signal_fd = -1, notify = -1, fd = -1;
 720         char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
 721         char final[sizeof(temp)] = "";
 722         _cleanup_free_ char *socket_name = NULL;
 723         _cleanup_strv_free_erase_ char **l = NULL;
 724         _cleanup_fclose_ FILE *f = NULL;
 725         struct pollfd pollfd[_FD_MAX];
 726         sigset_t mask, oldmask;
 727         int r;
 728
 729         assert(ret);
 730
 731         if (flags & ASK_PASSWORD_NO_AGENT)
 732                 return -EUNATCH;
 733
 734         assert_se(sigemptyset(&mask) >= 0);
 735         assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
 736         assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0);
 737
 738         (void) mkdir_p_label("/run/systemd/ask-password", 0755);
 739
 740         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
 741                 r = ask_password_keyring(keyname, flags, ret);
 742                 if (r >= 0) {
 743                         r = 0;
 744                         goto finish;
 745                 } else if (r != -ENOKEY)
 746                         goto finish;
 747
 748                 notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
 749                 if (notify < 0) {
 750                         r = -errno;
 751                         goto finish;
 752                 }
 753                 if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0) {
 754                         r = -errno;
 755                         goto finish;
 756                 }
 757         }
 758
 759         fd = mkostemp_safe(temp);
 760         if (fd < 0) {
 761                 r = fd;
 762                 goto finish;
 763         }
 764
 765         (void) fchmod(fd, 0644);
 766
 767         f = fdopen(fd, "w");
 768         if (!f) {
 769                 r = -errno;
 770                 goto finish;
 771         }
 772
 773         fd = -1;
 774
 775         signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
 776         if (signal_fd < 0) {
 777                 r = -errno;
 778                 goto finish;
 779         }
 780
 781         socket_fd = create_socket(&socket_name);
 782         if (socket_fd < 0) {
 783                 r = socket_fd;
 784                 goto finish;
 785         }
 786
 787         fprintf(f,
 788                 "[Ask]\n"
 789                 "PID="PID_FMT"\n"
 790                 "Socket=%s\n"
 791                 "AcceptCached=%i\n"
 792                 "Echo=%i\n"
 793                 "NotAfter="USEC_FMT"\n",
 794                 getpid_cached(),
 795                 socket_name,
 796                 (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0,
 797                 (flags & ASK_PASSWORD_ECHO) ? 1 : 0,
 798                 until);
 799
 800         if (message)
 801                 fprintf(f, "Message=%s\n", message);
 802
 803         if (icon)
 804                 fprintf(f, "Icon=%s\n", icon);
 805
 806         if (id)
 807                 fprintf(f, "Id=%s\n", id);
 808
 809         r = fflush_and_check(f);
 810         if (r < 0)
 811                 goto finish;
 812
 813         memcpy(final, temp, sizeof(temp));
 814
 815         final[sizeof(final)-11] = 'a';
 816         final[sizeof(final)-10] = 's';
 817         final[sizeof(final)-9] = 'k';
 818
 819         if (rename(temp, final) < 0) {
 820                 r = -errno;
 821                 goto finish;
 822         }
 823
 824         zero(pollfd);
 825         pollfd[FD_SOCKET].fd = socket_fd;
 826         pollfd[FD_SOCKET].events = POLLIN;
 827         pollfd[FD_SIGNAL].fd = signal_fd;
 828         pollfd[FD_SIGNAL].events = POLLIN;
 829         pollfd[FD_INOTIFY].fd = notify;
 830         pollfd[FD_INOTIFY].events = POLLIN;
 831
 832         for (;;) {
 833                 char passphrase[LINE_MAX+1];
 834                 struct msghdr msghdr;
 835                 struct iovec iovec;
 836                 struct ucred *ucred;
 837                 union {
 838                         struct cmsghdr cmsghdr;
 839                         uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
 840                 } control;
 841                 ssize_t n;
 842                 int k;
 843                 usec_t t;
 844
 845                 t = now(CLOCK_MONOTONIC);
 846
 847                 if (until > 0 && until <= t) {
 848                         r = -ETIME;
 849                         goto finish;
 850                 }
 851
 852                 k = poll(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1);
 853                 if (k < 0) {
 854                         if (errno == EINTR)
 855                                 continue;
 856
 857                         r = -errno;
 858                         goto finish;
 859                 }
 860
 861                 if (k <= 0) {
 862                         r = -ETIME;
 863                         goto finish;
 864                 }
 865
 866                 if (pollfd[FD_SIGNAL].revents & POLLIN) {
 867                         r = -EINTR;
 868                         goto finish;
 869                 }
 870
 871                 if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
 872                         (void) flush_fd(notify);
 873
 874                         r = ask_password_keyring(keyname, flags, ret);
 875                         if (r >= 0) {
 876                                 r = 0;
 877                                 goto finish;
 878                         } else if (r != -ENOKEY)
 879                                 goto finish;
 880                 }
 881
 882                 if (pollfd[FD_SOCKET].revents == 0)
 883                         continue;
 884
 885                 if (pollfd[FD_SOCKET].revents != POLLIN) {
 886                         r = -EIO;
 887                         goto finish;
 888                 }
 889
 890                 iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
 891
 892                 zero(control);
 893                 zero(msghdr);
 894                 msghdr.msg_iov = &iovec;
 895                 msghdr.msg_iovlen = 1;
 896                 msghdr.msg_control = &control;
 897                 msghdr.msg_controllen = sizeof(control);
 898
 899                 n = recvmsg(socket_fd, &msghdr, 0);
 900                 if (n < 0) {
 901                         if (IN_SET(errno, EAGAIN, EINTR))
 902                                 continue;
 903
 904                         r = -errno;
 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                 if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) ||
 916                     control.cmsghdr.cmsg_level != SOL_SOCKET ||
 917                     control.cmsghdr.cmsg_type != SCM_CREDENTIALS ||
 918                     control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) {
 919                         log_debug("Received message without credentials. Ignoring.");
 920                         continue;
 921                 }
 922
 923                 ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
 924                 if (ucred->uid != 0) {
 925                         log_debug("Got request from unprivileged user. Ignoring.");
 926                         continue;
 927                 }
 928
 929                 if (passphrase[0] == '+') {
 930                         /* An empty message refers to the empty password */
 931                         if (n == 1)
 932                                 l = strv_new("");
 933                         else
 934                                 l = strv_parse_nulstr(passphrase+1, n-1);
 935                         explicit_bzero_safe(passphrase, n);
 936                         if (!l) {
 937                                 r = -ENOMEM;
 938                                 goto finish;
 939                         }
 940
 941                         if (strv_isempty(l)) {
 942                                 l = strv_free(l);
 943                                 log_debug("Invalid packet");
 944                                 continue;
 945                         }
 946
 947                         break;
 948                 }
 949
 950                 if (passphrase[0] == '-') {
 951                         r = -ECANCELED;
 952                         goto finish;
 953                 }
 954
 955                 log_debug("Invalid packet");
 956         }
 957
 958         if (keyname)
 959                 (void) add_to_keyring_and_log(keyname, flags, l);
 960
 961         *ret = TAKE_PTR(l);
 962         r = 0;
 963
 964 finish:
 965         if (socket_name)
 966                 (void) unlink(socket_name);
 967
 968         (void) unlink(temp);
 969
 970         if (final[0])
 971                 (void) unlink(final);
 972
 973         assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0);
 974         return r;
 975 }
 976
 977 int ask_password_auto(
 978                 const char *message,
 979                 const char *icon,
 980                 const char *id,
 981                 const char *keyname,
 982                 usec_t until,
 983                 AskPasswordFlags flags,
 984                 char ***ret) {
 985
 986         int r;
 987
 988         assert(ret);
 989
 990         if ((flags & ASK_PASSWORD_ACCEPT_CACHED) &&
 991             keyname &&
 992             ((flags & ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
 993             (flags & ASK_PASSWORD_NO_AGENT)) {
 994                 r = ask_password_keyring(keyname, flags, ret);
 995                 if (r != -ENOKEY)
 996                         return r;
 997         }
 998
 999         if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
1000                 return ask_password_tty(-1, message, keyname, until, flags, NULL, ret);
1001
1002         if (!(flags & ASK_PASSWORD_NO_AGENT))
1003                 return ask_password_agent(message, icon, id, keyname, until, flags, ret);
1004
1005         return -EUNATCH;
1006 }