1 /* $OpenBSD: tftp-proxy.c,v 1.15 2015/11/14 04:02:32 deraadt Exp $ 2 * 3 * Copyright (c) 2005 DLS Internet Services 4 * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include <sys/types.h> 31 #include <sys/ioctl.h> 32 #include <sys/socket.h> 33 #include <sys/uio.h> 34 35 #include <netinet/in.h> 36 #include <arpa/inet.h> 37 #include <arpa/tftp.h> 38 #include <net/if.h> 39 #include <net/pfvar.h> 40 #include <netdb.h> 41 42 #include <unistd.h> 43 #include <errno.h> 44 #include <err.h> 45 #include <pwd.h> 46 #include <stdio.h> 47 #include <syslog.h> 48 #include <string.h> 49 #include <stdlib.h> 50 #include <event.h> 51 52 #include "filter.h" 53 54 #define CHROOT_DIR "/var/empty" 55 #define NOPRIV_USER "proxy" 56 57 #define DEFTRANSWAIT 2 58 #define NTOP_BUFS 4 59 #define PKTSIZE SEGSIZE+4 60 61 const char *opcode(int); 62 const char *sock_ntop(struct sockaddr *); 63 static void usage(void); 64 65 struct proxy_listener { 66 struct event ev; 67 TAILQ_ENTRY(proxy_listener) entry; 68 int (*cmsg2dst)(struct cmsghdr *, struct sockaddr_storage *); 69 int s; 70 }; 71 72 void proxy_listen(const char *, const char *, int); 73 void proxy_listener_events(void); 74 int proxy_dst4(struct cmsghdr *, struct sockaddr_storage *); 75 int proxy_dst6(struct cmsghdr *, struct sockaddr_storage *); 76 void proxy_recv(int, short, void *); 77 78 struct fd_reply { 79 TAILQ_ENTRY(fd_reply) entry; 80 int fd; 81 }; 82 83 struct privproc { 84 struct event pop_ev; 85 struct event push_ev; 86 TAILQ_HEAD(, fd_reply) replies; 87 struct evbuffer *buf; 88 }; 89 90 void proxy_privproc(int, struct passwd *); 91 void privproc_push(int, short, void *); 92 void privproc_pop(int, short, void *); 93 94 void unprivproc_push(int, short, void *); 95 void unprivproc_pop(int, short, void *); 96 void unprivproc_timeout(int, short, void *); 97 98 char ntop_buf[NTOP_BUFS][INET6_ADDRSTRLEN]; 99 100 struct loggers { 101 void (*err)(int, const char *, ...); 102 void (*errx)(int, const char *, ...); 103 void (*warn)(const char *, ...); 104 void (*warnx)(const char *, ...); 105 void (*info)(const char *, ...); 106 }; 107 108 const struct loggers conslogger = { 109 err, 110 errx, 111 warn, 112 warnx, 113 warnx 114 }; 115 116 void syslog_err(int, const char *, ...); 117 void syslog_errx(int, const char *, ...); 118 void syslog_warn(const char *, ...); 119 void syslog_warnx(const char *, ...); 120 void syslog_info(const char *, ...); 121 void syslog_vstrerror(int, int, const char *, va_list); 122 123 const struct loggers syslogger = { 124 syslog_err, 125 syslog_errx, 126 syslog_warn, 127 syslog_warnx, 128 syslog_info, 129 }; 130 131 const struct loggers *logger = &conslogger; 132 133 #define lerr(_e, _f...) logger->err((_e), _f) 134 #define lerrx(_e, _f...) logger->errx((_e), _f) 135 #define lwarn(_f...) logger->warn(_f) 136 #define lwarnx(_f...) logger->warnx(_f) 137 #define linfo(_f...) logger->info(_f) 138 139 __dead void 140 usage(void) 141 { 142 extern char *__progname; 143 fprintf(stderr, "usage: %s [-46dv] [-a address] [-l address] [-p port]" 144 " [-w transwait]\n", __progname); 145 exit(1); 146 } 147 148 int debug = 0; 149 int verbose = 0; 150 struct timeval transwait = { DEFTRANSWAIT, 0 }; 151 152 int on = 1; 153 154 struct addr_pair { 155 struct sockaddr_storage src; 156 struct sockaddr_storage dst; 157 }; 158 159 struct proxy_request { 160 char buf[SEGSIZE_MAX + 4]; 161 size_t buflen; 162 163 struct addr_pair addrs; 164 165 struct event ev; 166 TAILQ_ENTRY(proxy_request) entry; 167 u_int32_t id; 168 }; 169 170 struct proxy_child { 171 TAILQ_HEAD(, proxy_request) fdrequests; 172 TAILQ_HEAD(, proxy_request) tmrequests; 173 struct event push_ev; 174 struct event pop_ev; 175 struct evbuffer *buf; 176 }; 177 178 struct proxy_child *child = NULL; 179 TAILQ_HEAD(, proxy_listener) proxy_listeners; 180 181 struct src_addr { 182 TAILQ_ENTRY(src_addr) entry; 183 struct sockaddr_storage addr; 184 socklen_t addrlen; 185 }; 186 TAILQ_HEAD(, src_addr) src_addrs; 187 188 void source_addresses(const char*, int); 189 190 int 191 main(int argc, char *argv[]) 192 { 193 extern char *__progname; 194 195 int c; 196 const char *errstr; 197 198 struct src_addr *saddr, *saddr2; 199 struct passwd *pw; 200 201 char *addr = "localhost"; 202 char *port = "6969"; 203 int family = AF_UNSPEC; 204 205 int pair[2]; 206 207 TAILQ_INIT(&src_addrs); 208 209 while ((c = getopt(argc, argv, "46a:dvl:p:w:")) != -1) { 210 switch (c) { 211 case '4': 212 family = AF_INET; 213 break; 214 case '6': 215 family = AF_INET6; 216 break; 217 case 'a': 218 source_addresses(optarg, family); 219 break; 220 case 'd': 221 verbose = debug = 1; 222 break; 223 case 'l': 224 addr = optarg; 225 break; 226 case 'p': 227 port = optarg; 228 break; 229 case 'v': 230 verbose = 1; 231 break; 232 case 'w': 233 transwait.tv_sec = strtonum(optarg, 1, 30, &errstr); 234 if (errstr) 235 errx(1, "wait is %s", errstr); 236 break; 237 default: 238 usage(); 239 /* NOTREACHED */ 240 } 241 } 242 243 if (geteuid() != 0) 244 errx(1, "need root privileges"); 245 246 if (!debug && daemon(1, 0) == -1) 247 err(1, "daemon"); 248 249 if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, PF_UNSPEC, pair) 250 == -1) 251 lerr(1, "socketpair"); 252 253 pw = getpwnam(NOPRIV_USER); 254 if (pw == NULL) 255 lerrx(1, "no %s user", NOPRIV_USER); 256 257 /* Family option may have been specified late. */ 258 if (family != AF_UNSPEC) 259 TAILQ_FOREACH_SAFE(saddr, &src_addrs, entry, saddr2) 260 if (saddr->addr.ss_family != family) { 261 TAILQ_REMOVE(&src_addrs, saddr, entry); 262 free(saddr); 263 } 264 265 switch (fork()) { 266 case -1: 267 lerr(1, "fork"); 268 269 case 0: 270 setproctitle("privproc"); 271 close(pair[1]); 272 proxy_privproc(pair[0], pw); 273 /* this never returns */ 274 275 default: 276 setproctitle("unprivproc"); 277 close(pair[0]); 278 break; 279 } 280 281 child = calloc(1, sizeof(*child)); 282 if (child == NULL) 283 lerr(1, "alloc(child)"); 284 285 child->buf = evbuffer_new(); 286 if (child->buf == NULL) 287 lerr(1, "child evbuffer"); 288 289 TAILQ_INIT(&child->fdrequests); 290 TAILQ_INIT(&child->tmrequests); 291 292 if (!debug) { 293 openlog(__progname, LOG_PID|LOG_NDELAY, LOG_DAEMON); 294 tzset(); 295 logger = &syslogger; 296 } 297 298 proxy_listen(addr, port, family); 299 300 /* open /dev/pf */ 301 init_filter(NULL, verbose); 302 303 /* revoke privs */ 304 if (chroot(CHROOT_DIR) == -1) 305 lerr(1, "chroot %s", CHROOT_DIR); 306 307 if (chdir("/") == -1) 308 lerr(1, "chdir %s", CHROOT_DIR); 309 310 if (setgroups(1, &pw->pw_gid) || 311 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || 312 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) 313 err(1, "unable to revoke privs"); 314 315 event_init(); 316 317 proxy_listener_events(); 318 319 event_set(&child->pop_ev, pair[1], EV_READ | EV_PERSIST, 320 unprivproc_pop, NULL); 321 event_set(&child->push_ev, pair[1], EV_WRITE, 322 unprivproc_push, NULL); 323 324 event_add(&child->pop_ev, NULL); 325 326 event_dispatch(); 327 328 return(0); 329 } 330 331 void 332 source_addresses(const char* name, int family) 333 { 334 struct addrinfo hints, *res, *res0; 335 struct src_addr *saddr; 336 int error; 337 338 memset(&hints, 0, sizeof(hints)); 339 hints.ai_family = family; 340 hints.ai_socktype = SOCK_DGRAM; 341 hints.ai_flags = AI_PASSIVE; 342 error = getaddrinfo(name, NULL, &hints, &res0); 343 if (error) 344 lerrx(1, "%s: %s", name, gai_strerror(error)); 345 for (res = res0; res != NULL; res = res->ai_next) { 346 if ((saddr = calloc(1, sizeof(struct src_addr))) == NULL) 347 lerrx(1, "calloc"); 348 memcpy(&(saddr->addr), res->ai_addr, res->ai_addrlen); 349 saddr->addrlen = res->ai_addrlen; 350 TAILQ_INSERT_TAIL(&src_addrs, saddr, entry); 351 } 352 freeaddrinfo(res0); 353 } 354 355 void 356 proxy_privproc(int s, struct passwd *pw) 357 { 358 extern char *__progname; 359 struct privproc p; 360 361 if (!debug) { 362 openlog(__progname, LOG_PID|LOG_NDELAY, LOG_DAEMON); 363 tzset(); 364 logger = &syslogger; 365 } 366 367 if (chroot(CHROOT_DIR) == -1) 368 lerr(1, "chroot to %s", CHROOT_DIR); 369 370 if (chdir("/") == -1) 371 lerr(1, "chdir to %s", CHROOT_DIR); 372 373 if (setgroups(1, &pw->pw_gid) || 374 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid)) 375 lerr(1, "unable to set group ids"); 376 377 if (pledge("stdio inet sendfd", NULL) == -1) 378 err(1, "pledge"); 379 380 TAILQ_INIT(&p.replies); 381 382 p.buf = evbuffer_new(); 383 if (p.buf == NULL) 384 err(1, "pop evbuffer_new"); 385 386 event_init(); 387 388 event_set(&p.pop_ev, s, EV_READ | EV_PERSIST, privproc_pop, &p); 389 event_set(&p.push_ev, s, EV_WRITE, privproc_push, &p); 390 391 event_add(&p.pop_ev, NULL); 392 393 event_dispatch(); 394 } 395 396 void 397 privproc_pop(int fd, short events, void *arg) 398 { 399 struct addr_pair req; 400 struct privproc *p = arg; 401 struct fd_reply *rep; 402 struct src_addr *saddr; 403 int add = 0; 404 405 switch (evbuffer_read(p->buf, fd, sizeof(req))) { 406 case 0: 407 lerrx(1, "unprivproc has gone"); 408 case -1: 409 switch (errno) { 410 case EAGAIN: 411 case EINTR: 412 return; 413 default: 414 lerr(1, "privproc_pop read"); 415 } 416 default: 417 break; 418 } 419 420 while (EVBUFFER_LENGTH(p->buf) >= sizeof(req)) { 421 evbuffer_remove(p->buf, &req, sizeof(req)); 422 423 /* do i really need to check this? */ 424 if (req.src.ss_family != req.dst.ss_family) 425 lerrx(1, "family mismatch"); 426 427 rep = calloc(1, sizeof(*rep)); 428 if (rep == NULL) 429 lerr(1, "reply calloc"); 430 431 rep->fd = socket(req.src.ss_family, SOCK_DGRAM | SOCK_NONBLOCK, 432 IPPROTO_UDP); 433 if (rep->fd == -1) 434 lerr(1, "privproc socket"); 435 436 if (setsockopt(rep->fd, SOL_SOCKET, SO_BINDANY, 437 &on, sizeof(on)) == -1) 438 lerr(1, "privproc setsockopt(BINDANY)"); 439 440 if (setsockopt(rep->fd, SOL_SOCKET, SO_REUSEADDR, 441 &on, sizeof(on)) == -1) 442 lerr(1, "privproc setsockopt(REUSEADDR)"); 443 444 if (setsockopt(rep->fd, SOL_SOCKET, SO_REUSEPORT, 445 &on, sizeof(on)) == -1) 446 lerr(1, "privproc setsockopt(REUSEPORT)"); 447 448 TAILQ_FOREACH(saddr, &src_addrs, entry) 449 if (saddr->addr.ss_family == req.src.ss_family) 450 break; 451 if (saddr == NULL) { 452 if (bind(rep->fd, (struct sockaddr *)&req.src, 453 req.src.ss_len) == -1) 454 lerr(1, "privproc bind"); 455 } else { 456 if (bind(rep->fd, (struct sockaddr*)&saddr->addr, 457 saddr->addrlen) == -1) 458 lerr(1, "privproc bind"); 459 } 460 461 if (TAILQ_EMPTY(&p->replies)) 462 add = 1; 463 464 TAILQ_INSERT_TAIL(&p->replies, rep, entry); 465 } 466 467 if (add) 468 event_add(&p->push_ev, NULL); 469 } 470 471 void 472 privproc_push(int fd, short events, void *arg) 473 { 474 struct privproc *p = arg; 475 struct fd_reply *rep; 476 477 struct msghdr msg; 478 union { 479 struct cmsghdr hdr; 480 char buf[CMSG_SPACE(sizeof(int))]; 481 } cmsgbuf; 482 struct cmsghdr *cmsg; 483 struct iovec iov; 484 int result = 0; 485 486 while ((rep = TAILQ_FIRST(&p->replies)) != NULL) { 487 memset(&msg, 0, sizeof(msg)); 488 489 msg.msg_control = (caddr_t)&cmsgbuf.buf; 490 msg.msg_controllen = sizeof(cmsgbuf.buf); 491 cmsg = CMSG_FIRSTHDR(&msg); 492 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 493 cmsg->cmsg_level = SOL_SOCKET; 494 cmsg->cmsg_type = SCM_RIGHTS; 495 *(int *)CMSG_DATA(cmsg) = rep->fd; 496 497 iov.iov_base = &result; 498 iov.iov_len = sizeof(int); 499 msg.msg_iov = &iov; 500 msg.msg_iovlen = 1; 501 502 switch (sendmsg(fd, &msg, 0)) { 503 case sizeof(int): 504 break; 505 506 case -1: 507 if (errno == EAGAIN) 508 goto again; 509 510 lerr(1, "privproc sendmsg"); 511 /* NOTREACHED */ 512 513 default: 514 lerrx(1, "privproc sendmsg weird len"); 515 } 516 517 TAILQ_REMOVE(&p->replies, rep, entry); 518 close(rep->fd); 519 free(rep); 520 } 521 522 if (TAILQ_EMPTY(&p->replies)) 523 return; 524 525 again: 526 event_add(&p->push_ev, NULL); 527 } 528 529 void 530 proxy_listen(const char *addr, const char *port, int family) 531 { 532 struct proxy_listener *l; 533 534 struct addrinfo hints, *res, *res0; 535 int error; 536 int s, on = 1; 537 int serrno; 538 const char *cause = NULL; 539 540 memset(&hints, 0, sizeof(hints)); 541 hints.ai_family = family; 542 hints.ai_socktype = SOCK_DGRAM; 543 hints.ai_flags = AI_PASSIVE; 544 545 TAILQ_INIT(&proxy_listeners); 546 547 error = getaddrinfo(addr, port, &hints, &res0); 548 if (error) 549 errx(1, "%s:%s: %s", addr, port, gai_strerror(error)); 550 551 for (res = res0; res != NULL; res = res->ai_next) { 552 s = socket(res->ai_family, res->ai_socktype | SOCK_NONBLOCK, 553 res->ai_protocol); 554 if (s == -1) { 555 cause = "socket"; 556 continue; 557 } 558 559 if (bind(s, res->ai_addr, res->ai_addrlen) == -1) { 560 cause = "bind"; 561 serrno = errno; 562 close(s); 563 errno = serrno; 564 continue; 565 } 566 567 l = calloc(1, sizeof(*l)); 568 if (l == NULL) 569 err(1, "listener alloc"); 570 571 switch (res->ai_family) { 572 case AF_INET: 573 l->cmsg2dst = proxy_dst4; 574 575 if (setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, 576 &on, sizeof(on)) == -1) 577 errx(1, "setsockopt(IP_RECVDSTADDR)"); 578 if (setsockopt(s, IPPROTO_IP, IP_RECVDSTPORT, 579 &on, sizeof(on)) == -1) 580 errx(1, "setsockopt(IP_RECVDSTPORT)"); 581 break; 582 case AF_INET6: 583 l->cmsg2dst = proxy_dst6; 584 585 if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, 586 &on, sizeof(on)) == -1) 587 errx(1, "setsockopt(IPV6_RECVPKTINFO)"); 588 if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVDSTPORT, 589 &on, sizeof(on)) == -1) 590 errx(1, "setsockopt(IPV6_RECVDSTPORT)"); 591 break; 592 } 593 l->s = s; 594 595 TAILQ_INSERT_TAIL(&proxy_listeners, l, entry); 596 } 597 freeaddrinfo(res0); 598 599 if (TAILQ_EMPTY(&proxy_listeners)) 600 err(1, "%s", cause); 601 } 602 603 void 604 proxy_listener_events(void) 605 { 606 struct proxy_listener *l; 607 608 TAILQ_FOREACH(l, &proxy_listeners, entry) { 609 event_set(&l->ev, l->s, EV_READ | EV_PERSIST, proxy_recv, l); 610 event_add(&l->ev, NULL); 611 } 612 } 613 614 char safety[SEGSIZE_MAX + 4]; 615 616 int 617 proxy_dst4(struct cmsghdr *cmsg, struct sockaddr_storage *ss) 618 { 619 struct sockaddr_in *sin = (struct sockaddr_in *)ss; 620 621 if (cmsg->cmsg_level != IPPROTO_IP) 622 return (0); 623 624 switch (cmsg->cmsg_type) { 625 case IP_RECVDSTADDR: 626 memcpy(&sin->sin_addr, CMSG_DATA(cmsg), sizeof(sin->sin_addr)); 627 if (sin->sin_addr.s_addr == INADDR_BROADCAST) 628 return (-1); 629 break; 630 631 case IP_RECVDSTPORT: 632 memcpy(&sin->sin_port, CMSG_DATA(cmsg), sizeof(sin->sin_port)); 633 break; 634 } 635 636 return (0); 637 } 638 639 int 640 proxy_dst6(struct cmsghdr *cmsg, struct sockaddr_storage *ss) 641 { 642 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ss; 643 struct in6_pktinfo *ipi = (struct in6_pktinfo *)CMSG_DATA(cmsg); 644 645 if (cmsg->cmsg_level != IPPROTO_IPV6) 646 return (0); 647 648 switch (cmsg->cmsg_type) { 649 case IPV6_PKTINFO: 650 memcpy(&sin6->sin6_addr, &ipi->ipi6_addr, 651 sizeof(sin6->sin6_addr)); 652 #ifdef __KAME__ 653 if (IN6_IS_ADDR_LINKLOCAL(&ipi->ipi6_addr)) 654 sin6->sin6_scope_id = ipi->ipi6_ifindex; 655 #endif 656 break; 657 case IPV6_RECVDSTPORT: 658 memcpy(&sin6->sin6_port, CMSG_DATA(cmsg), 659 sizeof(sin6->sin6_port)); 660 break; 661 } 662 663 return (0); 664 } 665 666 void 667 proxy_recv(int fd, short events, void *arg) 668 { 669 struct proxy_listener *l = arg; 670 671 union { 672 struct cmsghdr hdr; 673 char buf[CMSG_SPACE(sizeof(struct sockaddr_storage)) + 674 CMSG_SPACE(sizeof(in_port_t))]; 675 } cmsgbuf; 676 struct cmsghdr *cmsg; 677 struct msghdr msg; 678 struct iovec iov; 679 ssize_t n; 680 681 struct proxy_request *r; 682 struct tftphdr *tp; 683 684 r = calloc(1, sizeof(*r)); 685 if (r == NULL) { 686 recv(fd, safety, sizeof(safety), 0); 687 return; 688 } 689 r->id = arc4random(); /* XXX unique? */ 690 691 bzero(&msg, sizeof(msg)); 692 iov.iov_base = r->buf; 693 iov.iov_len = sizeof(r->buf); 694 msg.msg_name = &r->addrs.src; 695 msg.msg_namelen = sizeof(r->addrs.src); 696 msg.msg_iov = &iov; 697 msg.msg_iovlen = 1; 698 msg.msg_control = &cmsgbuf.buf; 699 msg.msg_controllen = sizeof(cmsgbuf.buf); 700 701 n = recvmsg(fd, &msg, 0); 702 if (n == -1) { 703 switch (errno) { 704 case EAGAIN: 705 case EINTR: 706 goto err; 707 default: 708 lerr(1, "recvmsg"); 709 /* NOTREACHED */ 710 } 711 } 712 r->buflen = n; 713 714 /* check the packet */ 715 if (n < 5) { 716 /* not enough to be a real packet */ 717 goto err; 718 } 719 tp = (struct tftphdr *)r->buf; 720 switch (ntohs(tp->th_opcode)) { 721 case RRQ: 722 case WRQ: 723 break; 724 default: 725 goto err; 726 } 727 728 r->addrs.dst.ss_family = r->addrs.src.ss_family; 729 r->addrs.dst.ss_len = r->addrs.src.ss_len; 730 731 /* get local address if possible */ 732 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 733 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 734 if (l->cmsg2dst(cmsg, &r->addrs.dst) == -1) 735 goto err; 736 } 737 738 if (verbose) { 739 linfo("%s:%d -> %s:%d \"%s %s\"", 740 sock_ntop((struct sockaddr *)&r->addrs.src), 741 ntohs(((struct sockaddr_in *)&r->addrs.src)->sin_port), 742 sock_ntop((struct sockaddr *)&r->addrs.dst), 743 ntohs(((struct sockaddr_in *)&r->addrs.dst)->sin_port), 744 opcode(ntohs(tp->th_opcode)), tp->th_stuff); 745 /* XXX tp->th_stuff could be garbage */ 746 } 747 748 TAILQ_INSERT_TAIL(&child->fdrequests, r, entry); 749 evbuffer_add(child->buf, &r->addrs, sizeof(r->addrs)); 750 event_add(&child->push_ev, NULL); 751 752 return; 753 754 err: 755 free(r); 756 } 757 758 void 759 unprivproc_push(int fd, short events, void *arg) 760 { 761 if (evbuffer_write(child->buf, fd) == -1) 762 lerr(1, "child evbuffer_write"); 763 764 if (EVBUFFER_LENGTH(child->buf)) 765 event_add(&child->push_ev, NULL); 766 } 767 768 void 769 unprivproc_pop(int fd, short events, void *arg) 770 { 771 struct proxy_request *r; 772 773 struct msghdr msg; 774 union { 775 struct cmsghdr hdr; 776 char buf[CMSG_SPACE(sizeof(int))]; 777 } cmsgbuf; 778 struct cmsghdr *cmsg; 779 struct iovec iov; 780 struct src_addr *src_addr; 781 struct sockaddr_storage saddr; 782 socklen_t len; 783 int result; 784 int s; 785 786 len = sizeof(saddr); 787 788 do { 789 memset(&msg, 0, sizeof(msg)); 790 iov.iov_base = &result; 791 iov.iov_len = sizeof(int); 792 msg.msg_iov = &iov; 793 msg.msg_iovlen = 1; 794 msg.msg_control = &cmsgbuf.buf; 795 msg.msg_controllen = sizeof(cmsgbuf.buf); 796 797 switch (recvmsg(fd, &msg, 0)) { 798 case sizeof(int): 799 break; 800 801 case -1: 802 switch (errno) { 803 case EAGAIN: 804 case EINTR: 805 return; 806 default: 807 lerr(1, "child recvmsg"); 808 } 809 /* NOTREACHED */ 810 811 case 0: 812 lerrx(1, "privproc closed connection"); 813 814 default: 815 lerrx(1, "child recvmsg was weird"); 816 /* NOTREACHED */ 817 } 818 819 if (result != 0) { 820 errno = result; 821 lerr(1, "child fdpass fail"); 822 } 823 824 cmsg = CMSG_FIRSTHDR(&msg); 825 if (cmsg == NULL) 826 lerrx(1, "%s: no message header", __func__); 827 828 if (cmsg->cmsg_type != SCM_RIGHTS) { 829 lerrx(1, "%s: expected type %d got %d", __func__, 830 SCM_RIGHTS, cmsg->cmsg_type); 831 } 832 833 s = (*(int *)CMSG_DATA(cmsg)); 834 835 r = TAILQ_FIRST(&child->fdrequests); 836 if (r == NULL) 837 lerrx(1, "got fd without a pending request"); 838 839 TAILQ_REMOVE(&child->fdrequests, r, entry); 840 841 /* get ready to add rules */ 842 if (prepare_commit(r->id) == -1) 843 lerr(1, "%s: prepare_commit", __func__); 844 845 TAILQ_FOREACH(src_addr, &src_addrs, entry) 846 if (src_addr->addr.ss_family == r->addrs.dst.ss_family) 847 break; 848 if (src_addr == NULL) { 849 if (add_filter(r->id, PF_IN, (struct sockaddr *) 850 &r->addrs.dst, (struct sockaddr *)&r->addrs.src, 851 ntohs(((struct sockaddr_in *)&r->addrs.src) 852 ->sin_port), IPPROTO_UDP) == -1) 853 lerr(1, "%s: couldn't add pass in", __func__); 854 } else { 855 if (getsockname(s, (struct sockaddr*)&saddr, &len) == -1) 856 lerr(1, "%s: getsockname", __func__); 857 if (add_rdr(r->id, (struct sockaddr *)&r->addrs.dst, 858 (struct sockaddr*)&saddr, 859 ntohs(((struct sockaddr_in *)&saddr)->sin_port), 860 (struct sockaddr *)&r->addrs.src, 861 ntohs(((struct sockaddr_in *)&r->addrs.src)-> 862 sin_port), IPPROTO_UDP ) == -1) 863 lerr(1, "%s: couldn't add rdr rule", __func__); 864 } 865 866 if (add_filter(r->id, PF_OUT, (struct sockaddr *)&r->addrs.dst, 867 (struct sockaddr *)&r->addrs.src, 868 ntohs(((struct sockaddr_in *)&r->addrs.src)->sin_port), 869 IPPROTO_UDP) == -1) 870 lerr(1, "%s: couldn't add pass out", __func__); 871 872 if (do_commit() == -1) 873 lerr(1, "%s: couldn't commit rules", __func__); 874 875 /* forward the initial tftp request and start the insanity */ 876 if (sendto(s, r->buf, r->buflen, 0, 877 (struct sockaddr *)&r->addrs.dst, 878 r->addrs.dst.ss_len) == -1) 879 lerr(1, "%s: unable to send", __func__); 880 881 close(s); 882 883 evtimer_set(&r->ev, unprivproc_timeout, r); 884 evtimer_add(&r->ev, &transwait); 885 886 TAILQ_INSERT_TAIL(&child->tmrequests, r, entry); 887 } while (!TAILQ_EMPTY(&child->fdrequests)); 888 } 889 890 void 891 unprivproc_timeout(int fd, short events, void *arg) 892 { 893 struct proxy_request *r = arg; 894 895 TAILQ_REMOVE(&child->tmrequests, r, entry); 896 897 /* delete our rdr rule and clean up */ 898 prepare_commit(r->id); 899 do_commit(); 900 901 free(r); 902 } 903 904 905 const char * 906 opcode(int code) 907 { 908 static char str[6]; 909 910 switch (code) { 911 case 1: 912 (void)snprintf(str, sizeof(str), "RRQ"); 913 break; 914 case 2: 915 (void)snprintf(str, sizeof(str), "WRQ"); 916 break; 917 default: 918 (void)snprintf(str, sizeof(str), "(%d)", code); 919 break; 920 } 921 922 return (str); 923 } 924 925 const char * 926 sock_ntop(struct sockaddr *sa) 927 { 928 static int n = 0; 929 930 /* Cycle to next buffer. */ 931 n = (n + 1) % NTOP_BUFS; 932 ntop_buf[n][0] = '\0'; 933 934 if (sa->sa_family == AF_INET) { 935 struct sockaddr_in *sin = (struct sockaddr_in *)sa; 936 937 return (inet_ntop(AF_INET, &sin->sin_addr, ntop_buf[n], 938 sizeof ntop_buf[0])); 939 } 940 941 if (sa->sa_family == AF_INET6) { 942 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa; 943 944 return (inet_ntop(AF_INET6, &sin6->sin6_addr, ntop_buf[n], 945 sizeof ntop_buf[0])); 946 } 947 948 return (NULL); 949 } 950 951 void 952 syslog_vstrerror(int e, int priority, const char *fmt, va_list ap) 953 { 954 char *s; 955 956 if (vasprintf(&s, fmt, ap) == -1) { 957 syslog(LOG_EMERG, "unable to alloc in syslog_vstrerror"); 958 exit(1); 959 } 960 961 syslog(priority, "%s: %s", s, strerror(e)); 962 963 free(s); 964 } 965 966 void 967 syslog_err(int ecode, const char *fmt, ...) 968 { 969 va_list ap; 970 971 va_start(ap, fmt); 972 syslog_vstrerror(errno, LOG_EMERG, fmt, ap); 973 va_end(ap); 974 975 exit(ecode); 976 } 977 978 void 979 syslog_errx(int ecode, const char *fmt, ...) 980 { 981 va_list ap; 982 983 va_start(ap, fmt); 984 vsyslog(LOG_WARNING, fmt, ap); 985 va_end(ap); 986 987 exit(ecode); 988 } 989 990 void 991 syslog_warn(const char *fmt, ...) 992 { 993 va_list ap; 994 995 va_start(ap, fmt); 996 syslog_vstrerror(errno, LOG_WARNING, fmt, ap); 997 va_end(ap); 998 } 999 1000 void 1001 syslog_warnx(const char *fmt, ...) 1002 { 1003 va_list ap; 1004 1005 va_start(ap, fmt); 1006 vsyslog(LOG_WARNING, fmt, ap); 1007 va_end(ap); 1008 } 1009 1010 void 1011 syslog_info(const char *fmt, ...) 1012 { 1013 va_list ap; 1014 1015 va_start(ap, fmt); 1016 vsyslog(LOG_INFO, fmt, ap); 1017 va_end(ap); 1018 } 1019 1020