1/* $OpenBSD: constraint.c,v 1.56 2023/12/20 15:36:36 otto 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 51int constraint_addr_init(struct constraint *); 52void constraint_addr_head_clear(struct constraint *); 53struct constraint * 54 constraint_byid(u_int32_t); 55struct constraint * 56 constraint_byfd(int); 57struct constraint * 58 constraint_bypid(pid_t); 59int constraint_close(u_int32_t); 60void constraint_update(void); 61int constraint_cmp(const void *, const void *); 62 63void priv_constraint_close(int, int); 64void priv_constraint_readquery(struct constraint *, struct ntp_addr_msg *, 65 uint8_t **); 66 67struct httpsdate * 68 httpsdate_init(const char *, const char *, const char *, 69 const char *, const u_int8_t *, size_t, int); 70void httpsdate_free(void *); 71int httpsdate_request(struct httpsdate *, struct timeval *, int); 72void *httpsdate_query(const char *, const char *, const char *, 73 const char *, const u_int8_t *, size_t, 74 struct timeval *, struct timeval *, int); 75 76char *tls_readline(struct tls *, size_t *, size_t *, struct timeval *); 77 78u_int constraint_cnt; 79extern u_int peer_cnt; 80extern struct imsgbuf *ibuf; /* priv */ 81extern struct imsgbuf *ibuf_main; /* chld */ 82 83struct 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 94int 95constraint_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 106int 107constraint_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 145void 146constraint_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 153int 154constraint_query(struct constraint *cstr, int synced) 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 am.synced = synced; 210 211 iov[iov_cnt].iov_base = &am; 212 iov[iov_cnt++].iov_len = sizeof(am); 213 if (cstr->addr_head.name) { 214 am.namelen = strlen(cstr->addr_head.name) + 1; 215 iov[iov_cnt].iov_base = cstr->addr_head.name; 216 iov[iov_cnt++].iov_len = am.namelen; 217 } 218 if (cstr->addr_head.path) { 219 am.pathlen = strlen(cstr->addr_head.path) + 1; 220 iov[iov_cnt].iov_base = cstr->addr_head.path; 221 iov[iov_cnt++].iov_len = am.pathlen; 222 } 223 224 imsg_composev(ibuf_main, IMSG_CONSTRAINT_QUERY, 225 cstr->id, 0, -1, iov, iov_cnt); 226 227 return (0); 228} 229 230void 231priv_constraint_msg(u_int32_t id, u_int8_t *data, size_t len, int argc, 232 char **argv) 233{ 234 struct ntp_addr_msg am; 235 struct ntp_addr *h; 236 struct constraint *cstr; 237 int pipes[2]; 238 int rv; 239 240 if ((cstr = constraint_byid(id)) != NULL) { 241 log_warnx("IMSG_CONSTRAINT_QUERY repeated for id %d", id); 242 return; 243 } 244 245 if (len < sizeof(am)) { 246 log_warnx("invalid IMSG_CONSTRAINT_QUERY received"); 247 return; 248 } 249 memcpy(&am, data, sizeof(am)); 250 if (len != (sizeof(am) + am.namelen + am.pathlen)) { 251 log_warnx("invalid IMSG_CONSTRAINT_QUERY received"); 252 return; 253 } 254 /* Additional imsg data is obtained in the unpriv child */ 255 256 if ((h = calloc(1, sizeof(*h))) == NULL) 257 fatal("calloc ntp_addr"); 258 memcpy(h, &am.a, sizeof(*h)); 259 h->next = NULL; 260 261 cstr = new_constraint(); 262 cstr->id = id; 263 cstr->addr = h; 264 cstr->addr_head.a = h; 265 constraint_add(cstr); 266 constraint_cnt++; 267 268 if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, AF_UNSPEC, 269 pipes) == -1) 270 fatal("%s pipes", __func__); 271 272 /* Prepare and send constraint data to child. */ 273 cstr->fd = pipes[0]; 274 imsg_init(&cstr->ibuf, cstr->fd); 275 if (imsg_compose(&cstr->ibuf, IMSG_CONSTRAINT_QUERY, id, 0, -1, 276 data, len) == -1) 277 fatal("%s: imsg_compose", __func__); 278 do { 279 rv = imsg_flush(&cstr->ibuf); 280 } while (rv == -1 && errno == EAGAIN); 281 if (rv == -1) 282 fatal("imsg_flush"); 283 284 /* 285 * Fork child handlers and make sure to do any sensitive work in the 286 * the (unprivileged) child. The parent should not do any parsing, 287 * certificate loading etc. 288 */ 289 cstr->pid = start_child(CONSTRAINT_PROC_NAME, pipes[1], argc, argv); 290} 291 292void 293priv_constraint_readquery(struct constraint *cstr, struct ntp_addr_msg *am, 294 uint8_t **data) 295{ 296 struct ntp_addr *h; 297 uint8_t *dptr; 298 int n; 299 struct imsg imsg; 300 size_t mlen; 301 302 /* Read the message our parent left us. */ 303 if (((n = imsg_read(&cstr->ibuf)) == -1 && errno != EAGAIN) || n == 0) 304 fatal("%s: imsg_read", __func__); 305 if (((n = imsg_get(&cstr->ibuf, &imsg)) == -1) || n == 0) 306 fatal("%s: imsg_get", __func__); 307 if (imsg.hdr.type != IMSG_CONSTRAINT_QUERY) 308 fatalx("%s: invalid message type", __func__); 309 310 /* 311 * Copy the message contents just like our father: 312 * priv_constraint_msg(). 313 */ 314 mlen = imsg.hdr.len - IMSG_HEADER_SIZE; 315 if (mlen < sizeof(*am)) 316 fatalx("%s: mlen < sizeof(*am)", __func__); 317 318 memcpy(am, imsg.data, sizeof(*am)); 319 if (mlen != (sizeof(*am) + am->namelen + am->pathlen)) 320 fatalx("%s: mlen < sizeof(*am) + am->namelen + am->pathlen", 321 __func__); 322 323 if ((h = calloc(1, sizeof(*h))) == NULL || 324 (*data = calloc(1, mlen)) == NULL) 325 fatal("%s: calloc", __func__); 326 327 memcpy(h, &am->a, sizeof(*h)); 328 h->next = NULL; 329 330 cstr->id = imsg.hdr.peerid; 331 cstr->addr = h; 332 cstr->addr_head.a = h; 333 334 dptr = imsg.data; 335 memcpy(*data, dptr + sizeof(*am), mlen - sizeof(*am)); 336 imsg_free(&imsg); 337} 338 339void 340priv_constraint_child(const char *pw_dir, uid_t pw_uid, gid_t pw_gid) 341{ 342 struct constraint cstr; 343 struct ntp_addr_msg am; 344 uint8_t *data; 345 static char addr[NI_MAXHOST]; 346 struct timeval rectv, xmttv; 347 struct sigaction sa; 348 void *ctx; 349 struct iovec iov[2]; 350 int i, rv; 351 352 log_procinit("constraint"); 353 354 if (setpriority(PRIO_PROCESS, 0, 0) == -1) 355 log_warn("could not set priority"); 356 357 /* load CA certs before chroot() */ 358 if ((conf->ca = tls_load_file(tls_default_ca_cert_file(), 359 &conf->ca_len, NULL)) == NULL) 360 fatalx("failed to load constraint ca"); 361 362 if (chroot(pw_dir) == -1) 363 fatal("chroot"); 364 if (chdir("/") == -1) 365 fatal("chdir(\"/\")"); 366 367 if (setgroups(1, &pw_gid) || 368 setresgid(pw_gid, pw_gid, pw_gid) || 369 setresuid(pw_uid, pw_uid, pw_uid)) 370 fatal("can't drop privileges"); 371 372 /* Reset all signal handlers */ 373 memset(&sa, 0, sizeof(sa)); 374 sigemptyset(&sa.sa_mask); 375 sa.sa_flags = SA_RESTART; 376 sa.sa_handler = SIG_DFL; 377 for (i = 1; i < _NSIG; i++) 378 sigaction(i, &sa, NULL); 379 380 if (pledge("stdio inet", NULL) == -1) 381 fatal("pledge"); 382 383 cstr.fd = CONSTRAINT_PASSFD; 384 imsg_init(&cstr.ibuf, cstr.fd); 385 priv_constraint_readquery(&cstr, &am, &data); 386 387 /* 388 * Get the IP address as name and set the process title accordingly. 389 * This only converts an address into a string and does not trigger 390 * any DNS operation, so it is safe to be called without the dns 391 * pledge. 392 */ 393 if (getnameinfo((struct sockaddr *)&cstr.addr->ss, 394 SA_LEN((struct sockaddr *)&cstr.addr->ss), 395 addr, sizeof(addr), NULL, 0, 396 NI_NUMERICHOST) != 0) 397 fatalx("%s getnameinfo", __func__); 398 399 log_debug("constraint request to %s", addr); 400 setproctitle("constraint from %s", addr); 401 (void)closefrom(CONSTRAINT_PASSFD + 1); 402 403 /* 404 * Set the close-on-exec flag to prevent leaking the communication 405 * channel to any exec'ed child. In theory this could never happen, 406 * constraints don't exec children and pledge() prevents it, 407 * but we keep it as a safety belt; especially for portability. 408 */ 409 if (fcntl(CONSTRAINT_PASSFD, F_SETFD, FD_CLOEXEC) == -1) 410 fatal("%s fcntl F_SETFD", __func__); 411 412 /* Get remaining data from imsg in the unpriv child */ 413 if (am.namelen) { 414 if ((cstr.addr_head.name = 415 get_string(data, am.namelen)) == NULL) 416 fatalx("invalid IMSG_CONSTRAINT_QUERY name"); 417 data += am.namelen; 418 } 419 if (am.pathlen) { 420 if ((cstr.addr_head.path = 421 get_string(data, am.pathlen)) == NULL) 422 fatalx("invalid IMSG_CONSTRAINT_QUERY path"); 423 } 424 425 /* Run! */ 426 if ((ctx = httpsdate_query(addr, 427 CONSTRAINT_PORT, cstr.addr_head.name, cstr.addr_head.path, 428 conf->ca, conf->ca_len, &rectv, &xmttv, am.synced)) == NULL) { 429 /* Abort with failure but without warning */ 430 exit(1); 431 } 432 433 iov[0].iov_base = &rectv; 434 iov[0].iov_len = sizeof(rectv); 435 iov[1].iov_base = &xmttv; 436 iov[1].iov_len = sizeof(xmttv); 437 imsg_composev(&cstr.ibuf, 438 IMSG_CONSTRAINT_RESULT, 0, 0, -1, iov, 2); 439 do { 440 rv = imsg_flush(&cstr.ibuf); 441 } while (rv == -1 && errno == EAGAIN); 442 443 /* Tear down the TLS connection after sending the result */ 444 httpsdate_free(ctx); 445 446 exit(0); 447} 448 449void 450priv_constraint_check_child(pid_t pid, int status) 451{ 452 struct constraint *cstr; 453 int fail, sig; 454 char *signame; 455 456 fail = sig = 0; 457 if (WIFSIGNALED(status)) { 458 sig = WTERMSIG(status); 459 } else if (WIFEXITED(status)) { 460 if (WEXITSTATUS(status) != 0) 461 fail = 1; 462 } else 463 fatalx("unexpected cause of SIGCHLD"); 464 465 if ((cstr = constraint_bypid(pid)) != NULL) { 466 if (sig) { 467 if (sig != SIGTERM) { 468 signame = strsignal(sig) ? 469 strsignal(sig) : "unknown"; 470 log_warnx("constraint %s; " 471 "terminated with signal %d (%s)", 472 log_ntp_addr(cstr->addr), sig, signame); 473 } 474 fail = 1; 475 } 476 477 priv_constraint_close(cstr->fd, fail); 478 } 479} 480 481void 482priv_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 494struct constraint * 495constraint_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 507struct constraint * 508constraint_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 520struct constraint * 521constraint_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 533int 534constraint_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 return (constraint_init(cstr)); 557} 558 559void 560priv_constraint_close(int fd, int fail) 561{ 562 struct constraint *cstr; 563 u_int32_t id; 564 565 if ((cstr = constraint_byfd(fd)) == NULL) { 566 log_warn("%s: fd %d: not found", __func__, fd); 567 return; 568 } 569 570 id = cstr->id; 571 constraint_remove(cstr); 572 constraint_cnt--; 573 574 imsg_compose(ibuf, IMSG_CONSTRAINT_CLOSE, id, 0, -1, 575 &fail, sizeof(fail)); 576} 577 578void 579constraint_add(struct constraint *cstr) 580{ 581 TAILQ_INSERT_TAIL(&conf->constraints, cstr, entry); 582} 583 584void 585constraint_remove(struct constraint *cstr) 586{ 587 TAILQ_REMOVE(&conf->constraints, cstr, entry); 588 589 msgbuf_clear(&cstr->ibuf.w); 590 if (cstr->fd != -1) 591 close(cstr->fd); 592 free(cstr->addr_head.name); 593 free(cstr->addr_head.path); 594 free(cstr->addr); 595 free(cstr); 596} 597 598void 599constraint_purge(void) 600{ 601 struct constraint *cstr, *ncstr; 602 603 TAILQ_FOREACH_SAFE(cstr, &conf->constraints, entry, ncstr) 604 constraint_remove(cstr); 605} 606 607int 608priv_constraint_dispatch(struct pollfd *pfd) 609{ 610 struct imsg imsg; 611 struct constraint *cstr; 612 ssize_t n; 613 struct timeval tv[2]; 614 615 if ((cstr = constraint_byfd(pfd->fd)) == NULL) 616 return (0); 617 618 if (!(pfd->revents & POLLIN)) 619 return (0); 620 621 if (((n = imsg_read(&cstr->ibuf)) == -1 && errno != EAGAIN) || n == 0) { 622 /* there's a race between SIGCHLD delivery and reading imsg 623 but if we've seen the reply, we're good */ 624 priv_constraint_close(pfd->fd, cstr->state != 625 STATE_REPLY_RECEIVED); 626 return (1); 627 } 628 629 for (;;) { 630 if ((n = imsg_get(&cstr->ibuf, &imsg)) == -1) { 631 priv_constraint_close(pfd->fd, 1); 632 return (1); 633 } 634 if (n == 0) 635 break; 636 637 switch (imsg.hdr.type) { 638 case IMSG_CONSTRAINT_RESULT: 639 if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof(tv)) 640 fatalx("invalid IMSG_CONSTRAINT received"); 641 642 /* state is maintained by child, but we want to 643 remember we've seen the result */ 644 cstr->state = STATE_REPLY_RECEIVED; 645 /* forward imsg to ntp child, don't parse it here */ 646 imsg_compose(ibuf, imsg.hdr.type, 647 cstr->id, 0, -1, imsg.data, sizeof(tv)); 648 break; 649 default: 650 break; 651 } 652 imsg_free(&imsg); 653 } 654 655 return (0); 656} 657 658void 659constraint_msg_result(u_int32_t id, u_int8_t *data, size_t len) 660{ 661 struct constraint *cstr; 662 struct timeval tv[2]; 663 double offset; 664 665 if ((cstr = constraint_byid(id)) == NULL) { 666 log_warnx("IMSG_CONSTRAINT_CLOSE with invalid constraint id"); 667 return; 668 } 669 670 if (len != sizeof(tv)) { 671 log_warnx("invalid IMSG_CONSTRAINT received"); 672 return; 673 } 674 675 memcpy(tv, data, len); 676 677 offset = gettime_from_timeval(&tv[0]) - 678 gettime_from_timeval(&tv[1]); 679 680 log_info("constraint reply from %s: offset %f", 681 log_ntp_addr(cstr->addr), 682 offset); 683 684 cstr->state = STATE_REPLY_RECEIVED; 685 cstr->last = getmonotime(); 686 cstr->constraint = tv[0].tv_sec; 687 688 constraint_update(); 689} 690 691void 692constraint_msg_close(u_int32_t id, u_int8_t *data, size_t len) 693{ 694 struct constraint *cstr, *tmp; 695 int fail, cnt; 696 static int total_fails; 697 698 if ((cstr = constraint_byid(id)) == NULL) { 699 log_warnx("IMSG_CONSTRAINT_CLOSE with invalid constraint id"); 700 return; 701 } 702 703 if (len != sizeof(int)) { 704 log_warnx("invalid IMSG_CONSTRAINT_CLOSE received"); 705 return; 706 } 707 708 memcpy(&fail, data, len); 709 710 if (fail) { 711 log_debug("no constraint reply from %s" 712 " received in time, next query %ds", 713 log_ntp_addr(cstr->addr), 714 CONSTRAINT_SCAN_INTERVAL); 715 716 cnt = 0; 717 TAILQ_FOREACH(tmp, &conf->constraints, entry) 718 cnt++; 719 if (cnt > 0 && ++total_fails >= cnt && 720 conf->constraint_median == 0) { 721 log_warnx("constraints configured but none available"); 722 total_fails = 0; 723 } 724 } 725 726 if (fail || cstr->state < STATE_QUERY_SENT) { 727 cstr->senderrors++; 728 constraint_close(cstr->id); 729 } 730} 731 732void 733constraint_msg_dns(u_int32_t id, u_int8_t *data, size_t len) 734{ 735 struct constraint *cstr, *ncstr = NULL; 736 u_int8_t *p; 737 struct ntp_addr *h; 738 739 if ((cstr = constraint_byid(id)) == NULL) { 740 log_debug("IMSG_CONSTRAINT_DNS with invalid constraint id"); 741 return; 742 } 743 if (cstr->addr != NULL) { 744 log_warnx("IMSG_CONSTRAINT_DNS but addr != NULL!"); 745 return; 746 } 747 if (len == 0) { 748 log_debug("%s FAILED", __func__); 749 cstr->state = STATE_DNS_TEMPFAIL; 750 return; 751 } 752 753 if (len % (sizeof(struct sockaddr_storage) + sizeof(int)) != 0) 754 fatalx("IMSG_CONSTRAINT_DNS len"); 755 756 if (cstr->addr_head.pool) { 757 struct constraint *n, *tmp; 758 TAILQ_FOREACH_SAFE(n, &conf->constraints, entry, tmp) { 759 if (cstr->id == n->id) 760 continue; 761 if (cstr->addr_head.pool == n->addr_head.pool) 762 constraint_remove(n); 763 } 764 } 765 766 p = data; 767 do { 768 if ((h = calloc(1, sizeof(*h))) == NULL) 769 fatal("calloc ntp_addr"); 770 memcpy(&h->ss, p, sizeof(h->ss)); 771 p += sizeof(h->ss); 772 len -= sizeof(h->ss); 773 memcpy(&h->notauth, p, sizeof(int)); 774 p += sizeof(int); 775 len -= sizeof(int); 776 777 if (ncstr == NULL || cstr->addr_head.pool) { 778 ncstr = new_constraint(); 779 ncstr->addr = h; 780 ncstr->addr_head.a = h; 781 ncstr->addr_head.name = strdup(cstr->addr_head.name); 782 ncstr->addr_head.path = strdup(cstr->addr_head.path); 783 if (ncstr->addr_head.name == NULL || 784 ncstr->addr_head.path == NULL) 785 fatal("calloc name"); 786 ncstr->addr_head.pool = cstr->addr_head.pool; 787 ncstr->state = STATE_DNS_DONE; 788 constraint_add(ncstr); 789 constraint_cnt += constraint_init(ncstr); 790 } else { 791 h->next = ncstr->addr; 792 ncstr->addr = h; 793 ncstr->addr_head.a = h; 794 } 795 } while (len); 796 797 constraint_remove(cstr); 798} 799 800int 801constraint_cmp(const void *a, const void *b) 802{ 803 time_t at = *(const time_t *)a; 804 time_t bt = *(const time_t *)b; 805 return at < bt ? -1 : (at > bt ? 1 : 0); 806} 807 808void 809constraint_update(void) 810{ 811 struct constraint *cstr; 812 int cnt, i; 813 time_t *values; 814 time_t now; 815 816 now = getmonotime(); 817 818 cnt = 0; 819 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 820 if (cstr->state != STATE_REPLY_RECEIVED) 821 continue; 822 cnt++; 823 } 824 if (cnt == 0) 825 return; 826 827 if ((values = calloc(cnt, sizeof(time_t))) == NULL) 828 fatal("calloc"); 829 830 i = 0; 831 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 832 if (cstr->state != STATE_REPLY_RECEIVED) 833 continue; 834 values[i++] = cstr->constraint + (now - cstr->last); 835 } 836 837 qsort(values, cnt, sizeof(time_t), constraint_cmp); 838 839 /* calculate median */ 840 i = cnt / 2; 841 if (cnt % 2 == 0) 842 conf->constraint_median = (values[i - 1] + values[i]) / 2; 843 else 844 conf->constraint_median = values[i]; 845 846 conf->constraint_last = now; 847 848 free(values); 849} 850 851void 852constraint_reset(void) 853{ 854 struct constraint *cstr; 855 856 TAILQ_FOREACH(cstr, &conf->constraints, entry) { 857 if (cstr->state == STATE_QUERY_SENT) 858 continue; 859 constraint_close(cstr->id); 860 constraint_addr_head_clear(cstr); 861 constraint_init(cstr); 862 } 863 conf->constraint_errors = 0; 864} 865 866int 867constraint_check(double val) 868{ 869 struct timeval tv; 870 double diff; 871 time_t now; 872 873 if (conf->constraint_median == 0) 874 return (0); 875 876 /* Calculate the constraint with the current offset */ 877 now = getmonotime(); 878 tv.tv_sec = conf->constraint_median + (now - conf->constraint_last); 879 tv.tv_usec = 0; 880 diff = fabs(val - gettime_from_timeval(&tv)); 881 882 if (diff > CONSTRAINT_MARGIN) { 883 if (conf->constraint_errors++ > 884 (CONSTRAINT_ERROR_MARGIN * peer_cnt)) { 885 constraint_reset(); 886 } 887 888 return (-1); 889 } 890 891 return (0); 892} 893 894struct httpsdate * 895httpsdate_init(const char *addr, const char *port, const char *hostname, 896 const char *path, const u_int8_t *ca, size_t ca_len, int synced) 897{ 898 struct httpsdate *httpsdate = NULL; 899 900 if ((httpsdate = calloc(1, sizeof(*httpsdate))) == NULL) 901 goto fail; 902 903 if (hostname == NULL) 904 hostname = addr; 905 906 if ((httpsdate->tls_addr = strdup(addr)) == NULL || 907 (httpsdate->tls_port = strdup(port)) == NULL || 908 (httpsdate->tls_hostname = strdup(hostname)) == NULL || 909 (httpsdate->tls_path = strdup(path)) == NULL) 910 goto fail; 911 912 if (asprintf(&httpsdate->tls_request, 913 "HEAD %s HTTP/1.1\r\nHost: %s\r\nConnection: close\r\n\r\n", 914 httpsdate->tls_path, httpsdate->tls_hostname) == -1) 915 goto fail; 916 917 if ((httpsdate->tls_config = tls_config_new()) == NULL) 918 goto fail; 919 if (tls_config_set_ca_mem(httpsdate->tls_config, ca, ca_len) == -1) 920 goto fail; 921 922 /* 923 * Due to the fact that we're trying to determine a constraint for time 924 * we do our own certificate validity checking, since the automatic 925 * version is based on our wallclock, which may well be inaccurate... 926 */ 927 if (!synced) { 928 log_debug("constraints: using received time in certificate validation"); 929 tls_config_insecure_noverifytime(httpsdate->tls_config); 930 } 931 932 return (httpsdate); 933 934 fail: 935 httpsdate_free(httpsdate); 936 return (NULL); 937} 938 939void 940httpsdate_free(void *arg) 941{ 942 struct httpsdate *httpsdate = arg; 943 if (httpsdate == NULL) 944 return; 945 if (httpsdate->tls_ctx) 946 tls_close(httpsdate->tls_ctx); 947 tls_free(httpsdate->tls_ctx); 948 tls_config_free(httpsdate->tls_config); 949 free(httpsdate->tls_addr); 950 free(httpsdate->tls_port); 951 free(httpsdate->tls_hostname); 952 free(httpsdate->tls_path); 953 free(httpsdate->tls_request); 954 free(httpsdate); 955} 956 957int 958httpsdate_request(struct httpsdate *httpsdate, struct timeval *when, int synced) 959{ 960 char timebuf1[32], timebuf2[32]; 961 size_t outlen = 0, maxlength = CONSTRAINT_MAXHEADERLENGTH, len; 962 char *line, *p, *buf; 963 time_t httptime, notbefore, notafter; 964 struct tm *tm; 965 ssize_t ret; 966 967 if ((httpsdate->tls_ctx = tls_client()) == NULL) 968 goto fail; 969 970 if (tls_configure(httpsdate->tls_ctx, httpsdate->tls_config) == -1) 971 goto fail; 972 973 /* 974 * libtls expects an address string, which can also be a DNS name, 975 * but we pass a pre-resolved IP address string in tls_addr so it 976 * does not trigger any DNS operation and is safe to be called 977 * without the dns pledge. 978 */ 979 if (tls_connect_servername(httpsdate->tls_ctx, httpsdate->tls_addr, 980 httpsdate->tls_port, httpsdate->tls_hostname) == -1) { 981 log_debug("tls connect failed: %s (%s): %s", 982 httpsdate->tls_addr, httpsdate->tls_hostname, 983 tls_error(httpsdate->tls_ctx)); 984 goto fail; 985 } 986 987 buf = httpsdate->tls_request; 988 len = strlen(httpsdate->tls_request); 989 while (len > 0) { 990 ret = tls_write(httpsdate->tls_ctx, buf, len); 991 if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) 992 continue; 993 if (ret == -1) { 994 log_warnx("tls write failed: %s (%s): %s", 995 httpsdate->tls_addr, httpsdate->tls_hostname, 996 tls_error(httpsdate->tls_ctx)); 997 goto fail; 998 } 999 buf += ret; 1000 len -= ret; 1001 } 1002 1003 while ((line = tls_readline(httpsdate->tls_ctx, &outlen, 1004 &maxlength, when)) != NULL) { 1005 line[strcspn(line, "\r\n")] = '\0'; 1006 1007 if ((p = strchr(line, ' ')) == NULL || *p == '\0') 1008 goto next; 1009 *p++ = '\0'; 1010 if (strcasecmp("Date:", line) != 0) 1011 goto next; 1012 1013 /* 1014 * Expect the date/time format as IMF-fixdate which is 1015 * mandated by HTTP/1.1 in the new RFC 7231 and was 1016 * preferred by RFC 2616. Other formats would be RFC 850 1017 * or ANSI C's asctime() - the latter doesn't include 1018 * the timezone which is required here. 1019 */ 1020 if (strptime(p, IMF_FIXDATE, 1021 &httpsdate->tls_tm) == NULL) { 1022 log_warnx("unsupported date format"); 1023 free(line); 1024 goto fail; 1025 } 1026 1027 free(line); 1028 break; 1029 next: 1030 free(line); 1031 } 1032 if (httpsdate->tls_tm.tm_year == 0) 1033 goto fail; 1034 1035 /* If we are synced, we already checked the certificate validity */ 1036 if (synced) 1037 return 0; 1038 1039 /* 1040 * Now manually check the validity of the certificate presented in the 1041 * TLS handshake, based on the time specified by the server's HTTP Date: 1042 * header. 1043 */ 1044 notbefore = tls_peer_cert_notbefore(httpsdate->tls_ctx); 1045 notafter = tls_peer_cert_notafter(httpsdate->tls_ctx); 1046 if ((httptime = timegm(&httpsdate->tls_tm)) == -1) 1047 goto fail; 1048 if (httptime <= notbefore) { 1049 if ((tm = gmtime(¬before)) == NULL) 1050 goto fail; 1051 if (strftime(timebuf1, sizeof(timebuf1), X509_DATE, tm) == 0) 1052 goto fail; 1053 if (strftime(timebuf2, sizeof(timebuf2), X509_DATE, 1054 &httpsdate->tls_tm) == 0) 1055 goto fail; 1056 log_warnx("tls certificate not yet valid: %s (%s): " 1057 "not before %s, now %s", httpsdate->tls_addr, 1058 httpsdate->tls_hostname, timebuf1, timebuf2); 1059 goto fail; 1060 } 1061 if (httptime >= notafter) { 1062 if ((tm = gmtime(¬after)) == NULL) 1063 goto fail; 1064 if (strftime(timebuf1, sizeof(timebuf1), X509_DATE, tm) == 0) 1065 goto fail; 1066 if (strftime(timebuf2, sizeof(timebuf2), X509_DATE, 1067 &httpsdate->tls_tm) == 0) 1068 goto fail; 1069 log_warnx("tls certificate expired: %s (%s): " 1070 "not after %s, now %s", httpsdate->tls_addr, 1071 httpsdate->tls_hostname, timebuf1, timebuf2); 1072 goto fail; 1073 } 1074 1075 return (0); 1076 1077 fail: 1078 httpsdate_free(httpsdate); 1079 return (-1); 1080} 1081 1082void * 1083httpsdate_query(const char *addr, const char *port, const char *hostname, 1084 const char *path, const u_int8_t *ca, size_t ca_len, 1085 struct timeval *rectv, struct timeval *xmttv, int synced) 1086{ 1087 struct httpsdate *httpsdate; 1088 struct timeval when; 1089 time_t t; 1090 1091 if ((httpsdate = httpsdate_init(addr, port, hostname, path, 1092 ca, ca_len, synced)) == NULL) 1093 return (NULL); 1094 1095 if (httpsdate_request(httpsdate, &when, synced) == -1) 1096 return (NULL); 1097 1098 /* Return parsed date as local time */ 1099 t = timegm(&httpsdate->tls_tm); 1100 1101 /* Report parsed Date: as "received time" */ 1102 rectv->tv_sec = t; 1103 rectv->tv_usec = 0; 1104 1105 /* And add delay as "transmit time" */ 1106 xmttv->tv_sec = when.tv_sec; 1107 xmttv->tv_usec = when.tv_usec; 1108 1109 return (httpsdate); 1110} 1111 1112/* Based on SSL_readline in ftp/fetch.c */ 1113char * 1114tls_readline(struct tls *tls, size_t *lenp, size_t *maxlength, 1115 struct timeval *when) 1116{ 1117 size_t i, len; 1118 char *buf, *q, c; 1119 ssize_t ret; 1120 1121 len = 128; 1122 if ((buf = malloc(len)) == NULL) 1123 fatal("Can't allocate memory for transfer buffer"); 1124 for (i = 0; ; i++) { 1125 if (i >= len - 1) { 1126 if ((q = reallocarray(buf, len, 2)) == NULL) 1127 fatal("Can't expand transfer buffer"); 1128 buf = q; 1129 len *= 2; 1130 } 1131 again: 1132 ret = tls_read(tls, &c, 1); 1133 if (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT) 1134 goto again; 1135 if (ret == -1) { 1136 /* SSL read error, ignore */ 1137 free(buf); 1138 return (NULL); 1139 } 1140 1141 if (maxlength != NULL && (*maxlength)-- == 0) { 1142 log_warnx("maximum length exceeded"); 1143 free(buf); 1144 return (NULL); 1145 } 1146 1147 buf[i] = c; 1148 if (c == '\n') 1149 break; 1150 } 1151 *lenp = i; 1152 if (gettimeofday(when, NULL) == -1) 1153 fatal("gettimeofday"); 1154 return (buf); 1155} 1156 1157char * 1158get_string(u_int8_t *ptr, size_t len) 1159{ 1160 size_t i; 1161 1162 for (i = 0; i < len; i++) 1163 if (!(isprint(ptr[i]) || isspace(ptr[i]))) 1164 break; 1165 1166 return strndup(ptr, i); 1167} 1168