1 /* $OpenBSD: constraint.c,v 1.52 2021/07/16 13:59:10 kn Exp $ */ 2 3 /* 4 * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/queue.h> 20 #include <sys/socket.h> 21 #include <sys/time.h> 22 #include <sys/types.h> 23 #include <sys/wait.h> 24 #include <sys/resource.h> 25 #include <sys/uio.h> 26 27 #include <netinet/in.h> 28 #include <arpa/inet.h> 29 30 #include <errno.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <fcntl.h> 34 #include <imsg.h> 35 #include <netdb.h> 36 #include <poll.h> 37 #include <signal.h> 38 #include <string.h> 39 #include <unistd.h> 40 #include <time.h> 41 #include <ctype.h> 42 #include <tls.h> 43 #include <pwd.h> 44 #include <math.h> 45 46 #include "ntpd.h" 47 48 #define IMF_FIXDATE "%a, %d %h %Y %T GMT" 49 #define X509_DATE "%Y-%m-%d %T UTC" 50 51 int constraint_addr_init(struct constraint *); 52 void constraint_addr_head_clear(struct constraint *); 53 struct constraint * 54 constraint_byid(u_int32_t); 55 struct constraint * 56 constraint_byfd(int); 57 struct constraint * 58 constraint_bypid(pid_t); 59 int constraint_close(u_int32_t); 60 void constraint_update(void); 61 int constraint_cmp(const void *, const void *); 62 63 void priv_constraint_close(int, int); 64 void priv_constraint_readquery(struct constraint *, struct ntp_addr_msg *, 65 uint8_t **); 66 67 struct httpsdate * 68 httpsdate_init(const char *, const char *, const char *, 69 const char *, const u_int8_t *, size_t); 70 void httpsdate_free(void *); 71 int httpsdate_request(struct httpsdate *, struct timeval *); 72 void *httpsdate_query(const char *, const char *, const char *, 73 const char *, const u_int8_t *, size_t, 74 struct timeval *, struct timeval *); 75 76 char *tls_readline(struct tls *, size_t *, size_t *, struct timeval *); 77 78 u_int constraint_cnt; 79 extern u_int peer_cnt; 80 extern struct imsgbuf *ibuf; /* priv */ 81 extern struct imsgbuf *ibuf_main; /* chld */ 82 83 struct httpsdate { 84 char *tls_addr; 85 char *tls_port; 86 char *tls_hostname; 87 char *tls_path; 88 char *tls_request; 89 struct tls_config *tls_config; 90 struct tls *tls_ctx; 91 struct tm tls_tm; 92 }; 93 94 int 95 constraint_init(struct constraint *cstr) 96 { 97 cstr->state = STATE_NONE; 98 cstr->fd = -1; 99 cstr->last = getmonotime(); 100 cstr->constraint = 0; 101 cstr->senderrors = 0; 102 103 return (constraint_addr_init(cstr)); 104 } 105 106 int 107 constraint_addr_init(struct constraint *cstr) 108 { 109 struct sockaddr_in *sa_in; 110 struct sockaddr_in6 *sa_in6; 111 struct ntp_addr *h; 112 113 if (cstr->state == STATE_DNS_INPROGRESS) 114 return (0); 115 116 if (cstr->addr_head.a == NULL) { 117 priv_dns(IMSG_CONSTRAINT_DNS, cstr->addr_head.name, cstr->id); 118 cstr->state = STATE_DNS_INPROGRESS; 119 return (0); 120 } 121 122 h = cstr->addr; 123 switch (h->ss.ss_family) { 124 case AF_INET: 125 sa_in = (struct sockaddr_in *)&h->ss; 126 if (ntohs(sa_in->sin_port) == 0) 127 sa_in->sin_port = htons(443); 128 cstr->state = STATE_DNS_DONE; 129 break; 130 case AF_INET6: 131 sa_in6 = (struct sockaddr_in6 *)&h->ss; 132 if (ntohs(sa_in6->sin6_port) == 0) 133 sa_in6->sin6_port = htons(443); 134 cstr->state = STATE_DNS_DONE; 135 break; 136 default: 137 /* XXX king bula sez it? */ 138 fatalx("wrong AF in constraint_addr_init"); 139 /* NOTREACHED */ 140 } 141 142 return (1); 143 } 144 145 void 146 constraint_addr_head_clear(struct constraint *cstr) 147 { 148 host_dns_free(cstr->addr_head.a); 149 cstr->addr_head.a = NULL; 150 cstr->addr = NULL; 151 } 152 153 int 154 constraint_query(struct constraint *cstr) 155 { 156 time_t now; 157 struct ntp_addr_msg am; 158 struct iovec iov[3]; 159 int iov_cnt = 0; 160 161 now = getmonotime(); 162 163 switch (cstr->state) { 164 case STATE_DNS_DONE: 165 /* Proceed and query the time */ 166 break; 167 case STATE_DNS_TEMPFAIL: 168 if (now > cstr->last + (cstr->dnstries >= TRIES_AUTO_DNSFAIL ? 169 CONSTRAINT_RETRY_INTERVAL : INTERVAL_AUIO_DNSFAIL)) { 170 cstr->dnstries++; 171 /* Retry resolving the address */ 172 constraint_init(cstr); 173 return 0; 174 } 175 return (-1); 176 case STATE_QUERY_SENT: 177 if (cstr->last + CONSTRAINT_SCAN_TIMEOUT > now) { 178 /* The caller should expect a reply */ 179 return (0); 180 } 181 182 /* Timeout, just kill the process to reset it. */ 183 imsg_compose(ibuf_main, IMSG_CONSTRAINT_KILL, 184 cstr->id, 0, -1, NULL, 0); 185 186 cstr->state = STATE_TIMEOUT; 187 return (-1); 188 case STATE_INVALID: 189 if (cstr->last + CONSTRAINT_SCAN_INTERVAL > now) { 190 /* Nothing to do */ 191 return (-1); 192 } 193 194 /* Reset and retry */ 195 cstr->senderrors = 0; 196 constraint_close(cstr->id); 197 break; 198 case STATE_REPLY_RECEIVED: 199 default: 200 /* Nothing to do */ 201 return (-1); 202 } 203 204 cstr->last = now; 205 cstr->state = STATE_QUERY_SENT; 206 207 memset(&am, 0, sizeof(am)); 208 memcpy(&am.a, cstr->addr, sizeof(am.a)); 209 210 iov[iov_cnt].iov_base = &am; 211 iov[iov_cnt++].iov_len = sizeof(am); 212 if (cstr->addr_head.name) { 213 am.namelen = strlen(cstr->addr_head.name) + 1; 214 iov[iov_cnt].iov_base = cstr->addr_head.name; 215 iov[iov_cnt++].iov_len = am.namelen; 216 } 217 if (cstr->addr_head.path) { 218 am.pathlen = strlen(cstr->addr_head.path) + 1; 219 iov[iov_cnt].iov_base = cstr->addr_head.path; 220 iov[iov_cnt++].iov_len = am.pathlen; 221 } 222 223 imsg_composev(ibuf_main, IMSG_CONSTRAINT_QUERY, 224 cstr->id, 0, -1, iov, iov_cnt); 225 226 return (0); 227 } 228 229 void 230 priv_constraint_msg(u_int32_t id, u_int8_t *data, size_t len, int argc, 231 char **argv) 232 { 233 struct ntp_addr_msg am; 234 struct ntp_addr *h; 235 struct constraint *cstr; 236 int pipes[2]; 237 int rv; 238 239 if ((cstr = constraint_byid(id)) != NULL) { 240 log_warnx("IMSG_CONSTRAINT_QUERY repeated for id %d", id); 241 return; 242 } 243 244 if (len < sizeof(am)) { 245 log_warnx("invalid IMSG_CONSTRAINT_QUERY received"); 246 return; 247 } 248 memcpy(&am, data, sizeof(am)); 249 if (len != (sizeof(am) + am.namelen + am.pathlen)) { 250 log_warnx("invalid IMSG_CONSTRAINT_QUERY received"); 251 return; 252 } 253 /* Additional imsg data is obtained in the unpriv child */ 254 255 if ((h = calloc(1, sizeof(*h))) == NULL) 256 fatal("calloc ntp_addr"); 257 memcpy(h, &am.a, sizeof(*h)); 258 h->next = NULL; 259 260 cstr = new_constraint(); 261 cstr->id = id; 262 cstr->addr = h; 263 cstr->addr_head.a = h; 264 constraint_add(cstr); 265 constraint_cnt++; 266 267 if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, AF_UNSPEC, 268 pipes) == -1) 269 fatal("%s pipes", __func__); 270 271 /* Prepare and send constraint data to child. */ 272 cstr->fd = pipes[0]; 273 imsg_init(&cstr->ibuf, cstr->fd); 274 if (imsg_compose(&cstr->ibuf, IMSG_CONSTRAINT_QUERY, id, 0, -1, 275 data, len) == -1) 276 fatal("%s: imsg_compose", __func__); 277 do { 278 rv = imsg_flush(&cstr->ibuf); 279 } while (rv == -1 && errno == EAGAIN); 280 if (rv == -1) 281 fatal("imsg_flush"); 282 283 /* 284 * Fork child handlers and make sure to do any sensitive work in the 285 * the (unprivileged) child. The parent should not do any parsing, 286 * certificate loading etc. 287 */ 288 cstr->pid = start_child(CONSTRAINT_PROC_NAME, pipes[1], argc, argv); 289 } 290 291 void 292 priv_constraint_readquery(struct constraint *cstr, struct ntp_addr_msg *am, 293 uint8_t **data) 294 { 295 struct ntp_addr *h; 296 uint8_t *dptr; 297 int n; 298 struct imsg imsg; 299 size_t mlen; 300 301 /* Read the message our parent left us. */ 302 if (((n = imsg_read(&cstr->ibuf)) == -1 && errno != EAGAIN) || n == 0) 303 fatal("%s: imsg_read", __func__); 304 if (((n = imsg_get(&cstr->ibuf, &imsg)) == -1) || n == 0) 305 fatal("%s: imsg_get", __func__); 306 if (imsg.hdr.type != IMSG_CONSTRAINT_QUERY) 307 fatalx("%s: invalid message type", __func__); 308 309 /* 310 * Copy the message contents just like our father: 311 * priv_constraint_msg(). 312 */ 313 mlen = imsg.hdr.len - IMSG_HEADER_SIZE; 314 if (mlen < sizeof(*am)) 315 fatalx("%s: mlen < sizeof(*am)", __func__); 316 317 memcpy(am, imsg.data, sizeof(*am)); 318 if (mlen != (sizeof(*am) + am->namelen + am->pathlen)) 319 fatalx("%s: mlen < sizeof(*am) + am->namelen + am->pathlen", 320 __func__); 321 322 if ((h = calloc(1, sizeof(*h))) == NULL || 323 (*data = calloc(1, mlen)) == NULL) 324 fatal("%s: calloc", __func__); 325 326 memcpy(h, &am->a, sizeof(*h)); 327 h->next = NULL; 328 329 cstr->id = imsg.hdr.peerid; 330 cstr->addr = h; 331 cstr->addr_head.a = h; 332 333 dptr = imsg.data; 334 memcpy(*data, dptr + sizeof(*am), mlen - sizeof(*am)); 335 imsg_free(&imsg); 336 } 337 338 void 339 priv_constraint_child(const char *pw_dir, uid_t pw_uid, gid_t pw_gid) 340 { 341 struct constraint cstr; 342 struct ntp_addr_msg am; 343 uint8_t *data; 344 static char addr[NI_MAXHOST]; 345 struct timeval rectv, xmttv; 346 struct sigaction sa; 347 void *ctx; 348 struct iovec iov[2]; 349 int i, rv; 350 351 log_procinit("constraint"); 352 353 if (setpriority(PRIO_PROCESS, 0, 0) == -1) 354 log_warn("could not set priority"); 355 356 /* load CA certs before chroot() */ 357 if ((conf->ca = tls_load_file(tls_default_ca_cert_file(), 358 &conf->ca_len, NULL)) == NULL) 359 fatalx("failed to load constraint ca"); 360 361 if (chroot(pw_dir) == -1) 362 fatal("chroot"); 363 if (chdir("/") == -1) 364 fatal("chdir(\"/\")"); 365 366 if (setgroups(1, &pw_gid) || 367 setresgid(pw_gid, pw_gid, pw_gid) || 368 setresuid(pw_uid, pw_uid, pw_uid)) 369 fatal("can't drop privileges"); 370 371 /* Reset all signal handlers */ 372 memset(&sa, 0, sizeof(sa)); 373 sigemptyset(&sa.sa_mask); 374 sa.sa_flags = SA_RESTART; 375 sa.sa_handler = SIG_DFL; 376 for (i = 1; i < _NSIG; i++) 377 sigaction(i, &sa, NULL); 378 379 if (pledge("stdio inet", NULL) == -1) 380 fatal("pledge"); 381 382 cstr.fd = CONSTRAINT_PASSFD; 383 imsg_init(&cstr.ibuf, cstr.fd); 384 priv_constraint_readquery(&cstr, &am, &data); 385 386 /* 387 * Get the IP address as name and set the process title accordingly. 388 * This only converts an address into a string and does not trigger 389 * any DNS operation, so it is safe to be called without the dns 390 * pledge. 391 */ 392 if (getnameinfo((struct sockaddr *)&cstr.addr->ss, 393 SA_LEN((struct sockaddr *)&cstr.addr->ss), 394 addr, sizeof(addr), NULL, 0, 395 NI_NUMERICHOST) != 0) 396 fatalx("%s getnameinfo", __func__); 397 398 log_debug("constraint request to %s", addr); 399 setproctitle("constraint from %s", addr); 400 (void)closefrom(CONSTRAINT_PASSFD + 1); 401 402 /* 403 * Set the close-on-exec flag to prevent leaking the communication 404 * channel to any exec'ed child. In theory this could never happen, 405 * constraints don't exec children and pledge() prevents it, 406 * but we keep it as a safety belt; especially for portability. 407 */ 408 if (fcntl(CONSTRAINT_PASSFD, F_SETFD, FD_CLOEXEC) == -1) 409 fatal("%s fcntl F_SETFD", __func__); 410 411 /* Get remaining data from imsg in the unpriv child */ 412 if (am.namelen) { 413 if ((cstr.addr_head.name = 414 get_string(data, am.namelen)) == NULL) 415 fatalx("invalid IMSG_CONSTRAINT_QUERY name"); 416 data += am.namelen; 417 } 418 if (am.pathlen) { 419 if ((cstr.addr_head.path = 420 get_string(data, am.pathlen)) == NULL) 421 fatalx("invalid IMSG_CONSTRAINT_QUERY path"); 422 } 423 424 /* Run! */ 425 if ((ctx = httpsdate_query(addr, 426 CONSTRAINT_PORT, cstr.addr_head.name, cstr.addr_head.path, 427 conf->ca, conf->ca_len, &rectv, &xmttv)) == NULL) { 428 /* Abort with failure but without warning */ 429 exit(1); 430 } 431 432 iov[0].iov_base = &rectv; 433 iov[0].iov_len = sizeof(rectv); 434 iov[1].iov_base = &xmttv; 435 iov[1].iov_len = sizeof(xmttv); 436 imsg_composev(&cstr.ibuf, 437 IMSG_CONSTRAINT_RESULT, 0, 0, -1, iov, 2); 438 do { 439 rv = imsg_flush(&cstr.ibuf); 440 } while (rv == -1 && errno == EAGAIN); 441 442 /* Tear down the TLS connection after sending the result */ 443 httpsdate_free(ctx); 444 445 exit(0); 446 } 447 448 void 449 priv_constraint_check_child(pid_t pid, int status) 450 { 451 struct constraint *cstr; 452 int fail, sig; 453 char *signame; 454 455 fail = sig = 0; 456 if (WIFSIGNALED(status)) { 457 sig = WTERMSIG(status); 458 } else if (WIFEXITED(status)) { 459 if (WEXITSTATUS(status) != 0) 460 fail = 1; 461 } else 462 fatalx("unexpected cause of SIGCHLD"); 463 464 if ((cstr = constraint_bypid(pid)) != NULL) { 465 if (sig) { 466 if (sig != SIGTERM) { 467 signame = strsignal(sig) ? 468 strsignal(sig) : "unknown"; 469 log_warnx("constraint %s; " 470 "terminated with signal %d (%s)", 471 log_sockaddr((struct sockaddr *) 472 &cstr->addr->ss), sig, signame); 473 } 474 fail = 1; 475 } 476 477 priv_constraint_close(cstr->fd, fail); 478 } 479 } 480 481 void 482 priv_constraint_kill(u_int32_t id) 483 { 484 struct constraint *cstr; 485 486 if ((cstr = constraint_byid(id)) == NULL) { 487 log_warnx("IMSG_CONSTRAINT_KILL for invalid id %d", id); 488 return; 489 } 490 491 kill(cstr->pid, SIGTERM); 492 } 493 494 struct constraint * 495 constraint_byid(u_int32_t id) 496 { 497 struct constraint *cstr; 498 499 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 500 if (cstr->id == id) 501 return (cstr); 502 } 503 504 return (NULL); 505 } 506 507 struct constraint * 508 constraint_byfd(int fd) 509 { 510 struct constraint *cstr; 511 512 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 513 if (cstr->fd == fd) 514 return (cstr); 515 } 516 517 return (NULL); 518 } 519 520 struct constraint * 521 constraint_bypid(pid_t pid) 522 { 523 struct constraint *cstr; 524 525 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 526 if (cstr->pid == pid) 527 return (cstr); 528 } 529 530 return (NULL); 531 } 532 533 int 534 constraint_close(u_int32_t id) 535 { 536 struct constraint *cstr; 537 538 if ((cstr = constraint_byid(id)) == NULL) { 539 log_warn("%s: id %d: not found", __func__, id); 540 return (0); 541 } 542 543 cstr->last = getmonotime(); 544 545 if (cstr->addr == NULL || (cstr->addr = cstr->addr->next) == NULL) { 546 /* Either a pool or all addresses have been tried */ 547 cstr->addr = cstr->addr_head.a; 548 if (cstr->senderrors) 549 cstr->state = STATE_INVALID; 550 else if (cstr->state >= STATE_QUERY_SENT) 551 cstr->state = STATE_DNS_DONE; 552 553 return (1); 554 } 555 556 /* Go on and try the next resolved address for this constraint */ 557 return (constraint_init(cstr)); 558 } 559 560 void 561 priv_constraint_close(int fd, int fail) 562 { 563 struct constraint *cstr; 564 u_int32_t id; 565 566 if ((cstr = constraint_byfd(fd)) == NULL) { 567 log_warn("%s: fd %d: not found", __func__, fd); 568 return; 569 } 570 571 id = cstr->id; 572 constraint_remove(cstr); 573 constraint_cnt--; 574 575 imsg_compose(ibuf, IMSG_CONSTRAINT_CLOSE, id, 0, -1, 576 &fail, sizeof(fail)); 577 } 578 579 void 580 constraint_add(struct constraint *cstr) 581 { 582 TAILQ_INSERT_TAIL(&conf->constraints, cstr, entry); 583 } 584 585 void 586 constraint_remove(struct constraint *cstr) 587 { 588 TAILQ_REMOVE(&conf->constraints, cstr, entry); 589 590 msgbuf_clear(&cstr->ibuf.w); 591 if (cstr->fd != -1) 592 close(cstr->fd); 593 free(cstr->addr_head.name); 594 free(cstr->addr_head.path); 595 free(cstr->addr); 596 free(cstr); 597 } 598 599 void 600 constraint_purge(void) 601 { 602 struct constraint *cstr, *ncstr; 603 604 TAILQ_FOREACH_SAFE(cstr, &conf->constraints, entry, ncstr) 605 constraint_remove(cstr); 606 } 607 608 int 609 priv_constraint_dispatch(struct pollfd *pfd) 610 { 611 struct imsg imsg; 612 struct constraint *cstr; 613 ssize_t n; 614 struct timeval tv[2]; 615 616 if ((cstr = constraint_byfd(pfd->fd)) == NULL) 617 return (0); 618 619 if (!(pfd->revents & POLLIN)) 620 return (0); 621 622 if (((n = imsg_read(&cstr->ibuf)) == -1 && errno != EAGAIN) || n == 0) { 623 /* there's a race between SIGCHLD delivery and reading imsg 624 but if we've seen the reply, we're good */ 625 priv_constraint_close(pfd->fd, cstr->state != 626 STATE_REPLY_RECEIVED); 627 return (1); 628 } 629 630 for (;;) { 631 if ((n = imsg_get(&cstr->ibuf, &imsg)) == -1) { 632 priv_constraint_close(pfd->fd, 1); 633 return (1); 634 } 635 if (n == 0) 636 break; 637 638 switch (imsg.hdr.type) { 639 case IMSG_CONSTRAINT_RESULT: 640 if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof(tv)) 641 fatalx("invalid IMSG_CONSTRAINT received"); 642 643 /* state is maintained by child, but we want to 644 remember we've seen the result */ 645 cstr->state = STATE_REPLY_RECEIVED; 646 /* forward imsg to ntp child, don't parse it here */ 647 imsg_compose(ibuf, imsg.hdr.type, 648 cstr->id, 0, -1, imsg.data, sizeof(tv)); 649 break; 650 default: 651 break; 652 } 653 imsg_free(&imsg); 654 } 655 656 return (0); 657 } 658 659 void 660 constraint_msg_result(u_int32_t id, u_int8_t *data, size_t len) 661 { 662 struct constraint *cstr; 663 struct timeval tv[2]; 664 double offset; 665 666 if ((cstr = constraint_byid(id)) == NULL) { 667 log_warnx("IMSG_CONSTRAINT_CLOSE with invalid constraint id"); 668 return; 669 } 670 671 if (len != sizeof(tv)) { 672 log_warnx("invalid IMSG_CONSTRAINT received"); 673 return; 674 } 675 676 memcpy(tv, data, len); 677 678 offset = gettime_from_timeval(&tv[0]) - 679 gettime_from_timeval(&tv[1]); 680 681 log_info("constraint reply from %s: offset %f", 682 log_sockaddr((struct sockaddr *)&cstr->addr->ss), 683 offset); 684 685 cstr->state = STATE_REPLY_RECEIVED; 686 cstr->last = getmonotime(); 687 cstr->constraint = tv[0].tv_sec; 688 689 constraint_update(); 690 } 691 692 void 693 constraint_msg_close(u_int32_t id, u_int8_t *data, size_t len) 694 { 695 struct constraint *cstr, *tmp; 696 int fail, cnt; 697 static int total_fails; 698 699 if ((cstr = constraint_byid(id)) == NULL) { 700 log_warnx("IMSG_CONSTRAINT_CLOSE with invalid constraint id"); 701 return; 702 } 703 704 if (len != sizeof(int)) { 705 log_warnx("invalid IMSG_CONSTRAINT_CLOSE received"); 706 return; 707 } 708 709 memcpy(&fail, data, len); 710 711 if (fail) { 712 log_debug("no constraint reply from %s" 713 " received in time, next query %ds", 714 log_sockaddr((struct sockaddr *) 715 &cstr->addr->ss), CONSTRAINT_SCAN_INTERVAL); 716 717 cnt = 0; 718 TAILQ_FOREACH(tmp, &conf->constraints, entry) 719 cnt++; 720 if (cnt > 0 && ++total_fails >= cnt && 721 conf->constraint_median == 0) { 722 log_warnx("constraints configured but none available"); 723 total_fails = 0; 724 } 725 } 726 727 if (fail || cstr->state < STATE_QUERY_SENT) { 728 cstr->senderrors++; 729 constraint_close(cstr->id); 730 } 731 } 732 733 void 734 constraint_msg_dns(u_int32_t id, u_int8_t *data, size_t len) 735 { 736 struct constraint *cstr, *ncstr = NULL; 737 u_int8_t *p; 738 struct ntp_addr *h; 739 740 if ((cstr = constraint_byid(id)) == NULL) { 741 log_debug("IMSG_CONSTRAINT_DNS with invalid constraint id"); 742 return; 743 } 744 if (cstr->addr != NULL) { 745 log_warnx("IMSG_CONSTRAINT_DNS but addr != NULL!"); 746 return; 747 } 748 if (len == 0) { 749 log_debug("%s FAILED", __func__); 750 cstr->state = STATE_DNS_TEMPFAIL; 751 return; 752 } 753 754 if (len % (sizeof(struct sockaddr_storage) + sizeof(int)) != 0) 755 fatalx("IMSG_CONSTRAINT_DNS len"); 756 757 if (cstr->addr_head.pool) { 758 struct constraint *n, *tmp; 759 TAILQ_FOREACH_SAFE(n, &conf->constraints, entry, tmp) { 760 if (cstr->id == n->id) 761 continue; 762 if (cstr->addr_head.pool == n->addr_head.pool) 763 constraint_remove(n); 764 } 765 } 766 767 p = data; 768 do { 769 if ((h = calloc(1, sizeof(*h))) == NULL) 770 fatal("calloc ntp_addr"); 771 memcpy(&h->ss, p, sizeof(h->ss)); 772 p += sizeof(h->ss); 773 len -= sizeof(h->ss); 774 memcpy(&h->notauth, p, sizeof(int)); 775 p += sizeof(int); 776 len -= sizeof(int); 777 778 if (ncstr == NULL || cstr->addr_head.pool) { 779 ncstr = new_constraint(); 780 ncstr->addr = h; 781 ncstr->addr_head.a = h; 782 ncstr->addr_head.name = strdup(cstr->addr_head.name); 783 ncstr->addr_head.path = strdup(cstr->addr_head.path); 784 if (ncstr->addr_head.name == NULL || 785 ncstr->addr_head.path == NULL) 786 fatal("calloc name"); 787 ncstr->addr_head.pool = cstr->addr_head.pool; 788 ncstr->state = STATE_DNS_DONE; 789 constraint_add(ncstr); 790 constraint_cnt += constraint_init(ncstr); 791 } else { 792 h->next = ncstr->addr; 793 ncstr->addr = h; 794 ncstr->addr_head.a = h; 795 } 796 } while (len); 797 798 constraint_remove(cstr); 799 } 800 801 int 802 constraint_cmp(const void *a, const void *b) 803 { 804 time_t at = *(const time_t *)a; 805 time_t bt = *(const time_t *)b; 806 return at < bt ? -1 : (at > bt ? 1 : 0); 807 } 808 809 void 810 constraint_update(void) 811 { 812 struct constraint *cstr; 813 int cnt, i; 814 time_t *values; 815 time_t now; 816 817 now = getmonotime(); 818 819 cnt = 0; 820 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 821 if (cstr->state != STATE_REPLY_RECEIVED) 822 continue; 823 cnt++; 824 } 825 if (cnt == 0) 826 return; 827 828 if ((values = calloc(cnt, sizeof(time_t))) == NULL) 829 fatal("calloc"); 830 831 i = 0; 832 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 833 if (cstr->state != STATE_REPLY_RECEIVED) 834 continue; 835 values[i++] = cstr->constraint + (now - cstr->last); 836 } 837 838 qsort(values, cnt, sizeof(time_t), constraint_cmp); 839 840 /* calculate median */ 841 i = cnt / 2; 842 if (cnt % 2 == 0) 843 conf->constraint_median = (values[i - 1] + values[i]) / 2; 844 else 845 conf->constraint_median = values[i]; 846 847 conf->constraint_last = now; 848 849 free(values); 850 } 851 852 void 853 constraint_reset(void) 854 { 855 struct constraint *cstr; 856 857 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 858 if (cstr->state == STATE_QUERY_SENT) 859 continue; 860 constraint_close(cstr->id); 861 constraint_addr_head_clear(cstr); 862 constraint_init(cstr); 863 } 864 conf->constraint_errors = 0; 865 } 866 867 int 868 constraint_check(double val) 869 { 870 struct timeval tv; 871 double diff; 872 time_t now; 873 874 if (conf->constraint_median == 0) 875 return (0); 876 877 /* Calculate the constraint with the current offset */ 878 now = getmonotime(); 879 tv.tv_sec = conf->constraint_median + (now - conf->constraint_last); 880 tv.tv_usec = 0; 881 diff = fabs(val - gettime_from_timeval(&tv)); 882 883 if (diff > CONSTRAINT_MARGIN) { 884 if (conf->constraint_errors++ > 885 (CONSTRAINT_ERROR_MARGIN * peer_cnt)) { 886 constraint_reset(); 887 } 888 889 return (-1); 890 } 891 892 return (0); 893 } 894 895 struct httpsdate * 896 httpsdate_init(const char *addr, const char *port, const char *hostname, 897 const char *path, const u_int8_t *ca, size_t ca_len) 898 { 899 struct httpsdate *httpsdate = NULL; 900 901 if ((httpsdate = calloc(1, sizeof(*httpsdate))) == NULL) 902 goto fail; 903 904 if (hostname == NULL) 905 hostname = addr; 906 907 if ((httpsdate->tls_addr = strdup(addr)) == NULL || 908 (httpsdate->tls_port = strdup(port)) == NULL || 909 (httpsdate->tls_hostname = strdup(hostname)) == NULL || 910 (httpsdate->tls_path = strdup(path)) == NULL) 911 goto fail; 912 913 if (asprintf(&httpsdate->tls_request, 914 "HEAD %s HTTP/1.1\r\nHost: %s\r\nConnection: close\r\n\r\n", 915 httpsdate->tls_path, httpsdate->tls_hostname) == -1) 916 goto fail; 917 918 if ((httpsdate->tls_config = tls_config_new()) == NULL) 919 goto fail; 920 if (tls_config_set_ca_mem(httpsdate->tls_config, ca, ca_len) == -1) 921 goto fail; 922 923 /* 924 * Due to the fact that we're trying to determine a constraint for time 925 * we do our own certificate validity checking, since the automatic 926 * version is based on our wallclock, which may well be inaccurate... 927 */ 928 tls_config_insecure_noverifytime(httpsdate->tls_config); 929 930 return (httpsdate); 931 932 fail: 933 httpsdate_free(httpsdate); 934 return (NULL); 935 } 936 937 void 938 httpsdate_free(void *arg) 939 { 940 struct httpsdate *httpsdate = arg; 941 if (httpsdate == NULL) 942 return; 943 if (httpsdate->tls_ctx) 944 tls_close(httpsdate->tls_ctx); 945 tls_free(httpsdate->tls_ctx); 946 tls_config_free(httpsdate->tls_config); 947 free(httpsdate->tls_addr); 948 free(httpsdate->tls_port); 949 free(httpsdate->tls_hostname); 950 free(httpsdate->tls_path); 951 free(httpsdate->tls_request); 952 free(httpsdate); 953 } 954 955 int 956 httpsdate_request(struct httpsdate *httpsdate, struct timeval *when) 957 { 958 char timebuf1[32], timebuf2[32]; 959 size_t outlen = 0, maxlength = CONSTRAINT_MAXHEADERLENGTH, len; 960 char *line, *p, *buf; 961 time_t httptime, notbefore, notafter; 962 struct tm *tm; 963 ssize_t ret; 964 965 if ((httpsdate->tls_ctx = tls_client()) == NULL) 966 goto fail; 967 968 if (tls_configure(httpsdate->tls_ctx, httpsdate->tls_config) == -1) 969 goto fail; 970 971 /* 972 * libtls expects an address string, which can also be a DNS name, 973 * but we pass a pre-resolved IP address string in tls_addr so it 974 * does not trigger any DNS operation and is safe to be called 975 * without the dns pledge. 976 */ 977 if (tls_connect_servername(httpsdate->tls_ctx, httpsdate->tls_addr, 978 httpsdate->tls_port, httpsdate->tls_hostname) == -1) { 979 log_debug("tls connect failed: %s (%s): %s", 980 httpsdate->tls_addr, httpsdate->tls_hostname, 981 tls_error(httpsdate->tls_ctx)); 982 goto fail; 983 } 984 985 buf = httpsdate->tls_request; 986 len = strlen(httpsdate->tls_request); 987 while (len > 0) { 988 ret = tls_write(httpsdate->tls_ctx, buf, len); 989 if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) 990 continue; 991 if (ret == -1) { 992 log_warnx("tls write failed: %s (%s): %s", 993 httpsdate->tls_addr, httpsdate->tls_hostname, 994 tls_error(httpsdate->tls_ctx)); 995 goto fail; 996 } 997 buf += ret; 998 len -= ret; 999 } 1000 1001 while ((line = tls_readline(httpsdate->tls_ctx, &outlen, 1002 &maxlength, when)) != NULL) { 1003 line[strcspn(line, "\r\n")] = '\0'; 1004 1005 if ((p = strchr(line, ' ')) == NULL || *p == '\0') 1006 goto next; 1007 *p++ = '\0'; 1008 if (strcasecmp("Date:", line) != 0) 1009 goto next; 1010 1011 /* 1012 * Expect the date/time format as IMF-fixdate which is 1013 * mandated by HTTP/1.1 in the new RFC 7231 and was 1014 * preferred by RFC 2616. Other formats would be RFC 850 1015 * or ANSI C's asctime() - the latter doesn't include 1016 * the timezone which is required here. 1017 */ 1018 if (strptime(p, IMF_FIXDATE, 1019 &httpsdate->tls_tm) == NULL) { 1020 log_warnx("unsupported date format"); 1021 free(line); 1022 return (-1); 1023 } 1024 1025 free(line); 1026 break; 1027 next: 1028 free(line); 1029 } 1030 1031 /* 1032 * Now manually check the validity of the certificate presented in the 1033 * TLS handshake, based on the time specified by the server's HTTP Date: 1034 * header. 1035 */ 1036 notbefore = tls_peer_cert_notbefore(httpsdate->tls_ctx); 1037 notafter = tls_peer_cert_notafter(httpsdate->tls_ctx); 1038 if ((httptime = timegm(&httpsdate->tls_tm)) == -1) 1039 goto fail; 1040 if (httptime <= notbefore) { 1041 if ((tm = gmtime(¬before)) == NULL) 1042 goto fail; 1043 if (strftime(timebuf1, sizeof(timebuf1), X509_DATE, tm) == 0) 1044 goto fail; 1045 if (strftime(timebuf2, sizeof(timebuf2), X509_DATE, 1046 &httpsdate->tls_tm) == 0) 1047 goto fail; 1048 log_warnx("tls certificate not yet valid: %s (%s): " 1049 "not before %s, now %s", httpsdate->tls_addr, 1050 httpsdate->tls_hostname, timebuf1, timebuf2); 1051 goto fail; 1052 } 1053 if (httptime >= notafter) { 1054 if ((tm = gmtime(¬after)) == NULL) 1055 goto fail; 1056 if (strftime(timebuf1, sizeof(timebuf1), X509_DATE, tm) == 0) 1057 goto fail; 1058 if (strftime(timebuf2, sizeof(timebuf2), X509_DATE, 1059 &httpsdate->tls_tm) == 0) 1060 goto fail; 1061 log_warnx("tls certificate expired: %s (%s): " 1062 "not after %s, now %s", httpsdate->tls_addr, 1063 httpsdate->tls_hostname, timebuf1, timebuf2); 1064 goto fail; 1065 } 1066 1067 return (0); 1068 1069 fail: 1070 httpsdate_free(httpsdate); 1071 return (-1); 1072 } 1073 1074 void * 1075 httpsdate_query(const char *addr, const char *port, const char *hostname, 1076 const char *path, const u_int8_t *ca, size_t ca_len, 1077 struct timeval *rectv, struct timeval *xmttv) 1078 { 1079 struct httpsdate *httpsdate; 1080 struct timeval when; 1081 time_t t; 1082 1083 if ((httpsdate = httpsdate_init(addr, port, hostname, path, 1084 ca, ca_len)) == NULL) 1085 return (NULL); 1086 1087 if (httpsdate_request(httpsdate, &when) == -1) 1088 return (NULL); 1089 1090 /* Return parsed date as local time */ 1091 t = timegm(&httpsdate->tls_tm); 1092 1093 /* Report parsed Date: as "received time" */ 1094 rectv->tv_sec = t; 1095 rectv->tv_usec = 0; 1096 1097 /* And add delay as "transmit time" */ 1098 xmttv->tv_sec = when.tv_sec; 1099 xmttv->tv_usec = when.tv_usec; 1100 1101 return (httpsdate); 1102 } 1103 1104 /* Based on SSL_readline in ftp/fetch.c */ 1105 char * 1106 tls_readline(struct tls *tls, size_t *lenp, size_t *maxlength, 1107 struct timeval *when) 1108 { 1109 size_t i, len; 1110 char *buf, *q, c; 1111 ssize_t ret; 1112 1113 len = 128; 1114 if ((buf = malloc(len)) == NULL) 1115 fatal("Can't allocate memory for transfer buffer"); 1116 for (i = 0; ; i++) { 1117 if (i >= len - 1) { 1118 if ((q = reallocarray(buf, len, 2)) == NULL) 1119 fatal("Can't expand transfer buffer"); 1120 buf = q; 1121 len *= 2; 1122 } 1123 again: 1124 ret = tls_read(tls, &c, 1); 1125 if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) 1126 goto again; 1127 if (ret == -1) { 1128 /* SSL read error, ignore */ 1129 free(buf); 1130 return (NULL); 1131 } 1132 1133 if (maxlength != NULL && (*maxlength)-- == 0) { 1134 log_warnx("maximum length exceeded"); 1135 free(buf); 1136 return (NULL); 1137 } 1138 1139 buf[i] = c; 1140 if (c == '\n') 1141 break; 1142 } 1143 *lenp = i; 1144 if (gettimeofday(when, NULL) == -1) 1145 fatal("gettimeofday"); 1146 return (buf); 1147 } 1148 1149 char * 1150 get_string(u_int8_t *ptr, size_t len) 1151 { 1152 size_t i; 1153 1154 for (i = 0; i < len; i++) 1155 if (!(isprint(ptr[i]) || isspace(ptr[i]))) 1156 break; 1157 1158 return strndup(ptr, i); 1159 } 1160