1 /* $OpenBSD: tftp-proxy.c,v 1.18 2016/02/24 16:34:47 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 "_tftp_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 lerrx(1, "need root privileges"); 245 246 if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, PF_UNSPEC, pair) 247 == -1) 248 lerr(1, "socketpair"); 249 250 pw = getpwnam(NOPRIV_USER); 251 if (pw == NULL) 252 lerrx(1, "no %s user", NOPRIV_USER); 253 254 /* Family option may have been specified late. */ 255 if (family != AF_UNSPEC) 256 TAILQ_FOREACH_SAFE(saddr, &src_addrs, entry, saddr2) 257 if (saddr->addr.ss_family != family) { 258 TAILQ_REMOVE(&src_addrs, saddr, entry); 259 free(saddr); 260 } 261 262 if (!debug) { 263 if (daemon(1, 0) == -1) 264 lerr(1, "daemon"); 265 266 openlog(__progname, LOG_PID|LOG_NDELAY, LOG_DAEMON); 267 tzset(); 268 logger = &syslogger; 269 } 270 271 switch (fork()) { 272 case -1: 273 lerr(1, "fork"); 274 275 case 0: 276 setproctitle("privproc"); 277 close(pair[1]); 278 proxy_privproc(pair[0], pw); 279 /* this never returns */ 280 281 default: 282 setproctitle("unprivproc"); 283 close(pair[0]); 284 break; 285 } 286 287 child = calloc(1, sizeof(*child)); 288 if (child == NULL) 289 lerr(1, "alloc(child)"); 290 291 child->buf = evbuffer_new(); 292 if (child->buf == NULL) 293 lerr(1, "child evbuffer"); 294 295 TAILQ_INIT(&child->fdrequests); 296 TAILQ_INIT(&child->tmrequests); 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 struct privproc p; 359 360 if (chroot(CHROOT_DIR) == -1) 361 lerr(1, "chroot to %s", CHROOT_DIR); 362 363 if (chdir("/") == -1) 364 lerr(1, "chdir to %s", CHROOT_DIR); 365 366 if (setgroups(1, &pw->pw_gid) || 367 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid)) 368 lerr(1, "unable to set group ids"); 369 370 if (pledge("stdio inet sendfd", NULL) == -1) 371 err(1, "pledge"); 372 373 TAILQ_INIT(&p.replies); 374 375 p.buf = evbuffer_new(); 376 if (p.buf == NULL) 377 err(1, "pop evbuffer_new"); 378 379 event_init(); 380 381 event_set(&p.pop_ev, s, EV_READ | EV_PERSIST, privproc_pop, &p); 382 event_set(&p.push_ev, s, EV_WRITE, privproc_push, &p); 383 384 event_add(&p.pop_ev, NULL); 385 386 event_dispatch(); 387 } 388 389 void 390 privproc_pop(int fd, short events, void *arg) 391 { 392 struct addr_pair req; 393 struct privproc *p = arg; 394 struct fd_reply *rep; 395 struct src_addr *saddr; 396 int add = 0; 397 398 switch (evbuffer_read(p->buf, fd, sizeof(req))) { 399 case 0: 400 lerrx(1, "unprivproc has gone"); 401 case -1: 402 switch (errno) { 403 case EAGAIN: 404 case EINTR: 405 return; 406 default: 407 lerr(1, "privproc_pop read"); 408 } 409 default: 410 break; 411 } 412 413 while (EVBUFFER_LENGTH(p->buf) >= sizeof(req)) { 414 evbuffer_remove(p->buf, &req, sizeof(req)); 415 416 /* do i really need to check this? */ 417 if (req.src.ss_family != req.dst.ss_family) 418 lerrx(1, "family mismatch"); 419 420 rep = calloc(1, sizeof(*rep)); 421 if (rep == NULL) 422 lerr(1, "reply calloc"); 423 424 rep->fd = socket(req.src.ss_family, SOCK_DGRAM | SOCK_NONBLOCK, 425 IPPROTO_UDP); 426 if (rep->fd == -1) 427 lerr(1, "privproc socket"); 428 429 if (setsockopt(rep->fd, SOL_SOCKET, SO_BINDANY, 430 &on, sizeof(on)) == -1) 431 lerr(1, "privproc setsockopt(BINDANY)"); 432 433 if (setsockopt(rep->fd, SOL_SOCKET, SO_REUSEADDR, 434 &on, sizeof(on)) == -1) 435 lerr(1, "privproc setsockopt(REUSEADDR)"); 436 437 if (setsockopt(rep->fd, SOL_SOCKET, SO_REUSEPORT, 438 &on, sizeof(on)) == -1) 439 lerr(1, "privproc setsockopt(REUSEPORT)"); 440 441 TAILQ_FOREACH(saddr, &src_addrs, entry) 442 if (saddr->addr.ss_family == req.src.ss_family) 443 break; 444 if (saddr == NULL) { 445 if (bind(rep->fd, (struct sockaddr *)&req.src, 446 req.src.ss_len) == -1) 447 lerr(1, "privproc bind"); 448 } else { 449 if (bind(rep->fd, (struct sockaddr*)&saddr->addr, 450 saddr->addrlen) == -1) 451 lerr(1, "privproc bind"); 452 } 453 454 if (TAILQ_EMPTY(&p->replies)) 455 add = 1; 456 457 TAILQ_INSERT_TAIL(&p->replies, rep, entry); 458 } 459 460 if (add) 461 event_add(&p->push_ev, NULL); 462 } 463 464 void 465 privproc_push(int fd, short events, void *arg) 466 { 467 struct privproc *p = arg; 468 struct fd_reply *rep; 469 470 struct msghdr msg; 471 union { 472 struct cmsghdr hdr; 473 char buf[CMSG_SPACE(sizeof(int))]; 474 } cmsgbuf; 475 struct cmsghdr *cmsg; 476 struct iovec iov; 477 int result = 0; 478 479 while ((rep = TAILQ_FIRST(&p->replies)) != NULL) { 480 memset(&msg, 0, sizeof(msg)); 481 482 msg.msg_control = (caddr_t)&cmsgbuf.buf; 483 msg.msg_controllen = sizeof(cmsgbuf.buf); 484 cmsg = CMSG_FIRSTHDR(&msg); 485 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 486 cmsg->cmsg_level = SOL_SOCKET; 487 cmsg->cmsg_type = SCM_RIGHTS; 488 *(int *)CMSG_DATA(cmsg) = rep->fd; 489 490 iov.iov_base = &result; 491 iov.iov_len = sizeof(int); 492 msg.msg_iov = &iov; 493 msg.msg_iovlen = 1; 494 495 switch (sendmsg(fd, &msg, 0)) { 496 case sizeof(int): 497 break; 498 499 case -1: 500 if (errno == EAGAIN) 501 goto again; 502 503 lerr(1, "privproc sendmsg"); 504 /* NOTREACHED */ 505 506 default: 507 lerrx(1, "privproc sendmsg weird len"); 508 } 509 510 TAILQ_REMOVE(&p->replies, rep, entry); 511 close(rep->fd); 512 free(rep); 513 } 514 515 if (TAILQ_EMPTY(&p->replies)) 516 return; 517 518 again: 519 event_add(&p->push_ev, NULL); 520 } 521 522 void 523 proxy_listen(const char *addr, const char *port, int family) 524 { 525 struct proxy_listener *l; 526 527 struct addrinfo hints, *res, *res0; 528 int error; 529 int s, on = 1; 530 int serrno; 531 const char *cause = NULL; 532 533 memset(&hints, 0, sizeof(hints)); 534 hints.ai_family = family; 535 hints.ai_socktype = SOCK_DGRAM; 536 hints.ai_flags = AI_PASSIVE; 537 538 TAILQ_INIT(&proxy_listeners); 539 540 error = getaddrinfo(addr, port, &hints, &res0); 541 if (error) 542 errx(1, "%s:%s: %s", addr, port, gai_strerror(error)); 543 544 for (res = res0; res != NULL; res = res->ai_next) { 545 s = socket(res->ai_family, res->ai_socktype | SOCK_NONBLOCK, 546 res->ai_protocol); 547 if (s == -1) { 548 cause = "socket"; 549 continue; 550 } 551 552 if (bind(s, res->ai_addr, res->ai_addrlen) == -1) { 553 cause = "bind"; 554 serrno = errno; 555 close(s); 556 errno = serrno; 557 continue; 558 } 559 560 l = calloc(1, sizeof(*l)); 561 if (l == NULL) 562 err(1, "listener alloc"); 563 564 switch (res->ai_family) { 565 case AF_INET: 566 l->cmsg2dst = proxy_dst4; 567 568 if (setsockopt(s, IPPROTO_IP, IP_RECVDSTADDR, 569 &on, sizeof(on)) == -1) 570 errx(1, "setsockopt(IP_RECVDSTADDR)"); 571 if (setsockopt(s, IPPROTO_IP, IP_RECVDSTPORT, 572 &on, sizeof(on)) == -1) 573 errx(1, "setsockopt(IP_RECVDSTPORT)"); 574 break; 575 case AF_INET6: 576 l->cmsg2dst = proxy_dst6; 577 578 if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, 579 &on, sizeof(on)) == -1) 580 errx(1, "setsockopt(IPV6_RECVPKTINFO)"); 581 if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVDSTPORT, 582 &on, sizeof(on)) == -1) 583 errx(1, "setsockopt(IPV6_RECVDSTPORT)"); 584 break; 585 } 586 l->s = s; 587 588 TAILQ_INSERT_TAIL(&proxy_listeners, l, entry); 589 } 590 freeaddrinfo(res0); 591 592 if (TAILQ_EMPTY(&proxy_listeners)) 593 err(1, "%s", cause); 594 } 595 596 void 597 proxy_listener_events(void) 598 { 599 struct proxy_listener *l; 600 601 TAILQ_FOREACH(l, &proxy_listeners, entry) { 602 event_set(&l->ev, l->s, EV_READ | EV_PERSIST, proxy_recv, l); 603 event_add(&l->ev, NULL); 604 } 605 } 606 607 char safety[SEGSIZE_MAX + 4]; 608 609 int 610 proxy_dst4(struct cmsghdr *cmsg, struct sockaddr_storage *ss) 611 { 612 struct sockaddr_in *sin = (struct sockaddr_in *)ss; 613 614 if (cmsg->cmsg_level != IPPROTO_IP) 615 return (0); 616 617 switch (cmsg->cmsg_type) { 618 case IP_RECVDSTADDR: 619 memcpy(&sin->sin_addr, CMSG_DATA(cmsg), sizeof(sin->sin_addr)); 620 if (sin->sin_addr.s_addr == INADDR_BROADCAST) 621 return (-1); 622 break; 623 624 case IP_RECVDSTPORT: 625 memcpy(&sin->sin_port, CMSG_DATA(cmsg), sizeof(sin->sin_port)); 626 break; 627 } 628 629 return (0); 630 } 631 632 int 633 proxy_dst6(struct cmsghdr *cmsg, struct sockaddr_storage *ss) 634 { 635 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ss; 636 struct in6_pktinfo *ipi = (struct in6_pktinfo *)CMSG_DATA(cmsg); 637 638 if (cmsg->cmsg_level != IPPROTO_IPV6) 639 return (0); 640 641 switch (cmsg->cmsg_type) { 642 case IPV6_PKTINFO: 643 memcpy(&sin6->sin6_addr, &ipi->ipi6_addr, 644 sizeof(sin6->sin6_addr)); 645 #ifdef __KAME__ 646 if (IN6_IS_ADDR_LINKLOCAL(&ipi->ipi6_addr)) 647 sin6->sin6_scope_id = ipi->ipi6_ifindex; 648 #endif 649 break; 650 case IPV6_RECVDSTPORT: 651 memcpy(&sin6->sin6_port, CMSG_DATA(cmsg), 652 sizeof(sin6->sin6_port)); 653 break; 654 } 655 656 return (0); 657 } 658 659 void 660 proxy_recv(int fd, short events, void *arg) 661 { 662 struct proxy_listener *l = arg; 663 664 union { 665 struct cmsghdr hdr; 666 char buf[CMSG_SPACE(sizeof(struct sockaddr_storage)) + 667 CMSG_SPACE(sizeof(in_port_t))]; 668 } cmsgbuf; 669 struct cmsghdr *cmsg; 670 struct msghdr msg; 671 struct iovec iov; 672 ssize_t n; 673 674 struct proxy_request *r; 675 struct tftphdr *tp; 676 677 r = calloc(1, sizeof(*r)); 678 if (r == NULL) { 679 recv(fd, safety, sizeof(safety), 0); 680 return; 681 } 682 r->id = arc4random(); /* XXX unique? */ 683 684 bzero(&msg, sizeof(msg)); 685 iov.iov_base = r->buf; 686 iov.iov_len = sizeof(r->buf); 687 msg.msg_name = &r->addrs.src; 688 msg.msg_namelen = sizeof(r->addrs.src); 689 msg.msg_iov = &iov; 690 msg.msg_iovlen = 1; 691 msg.msg_control = &cmsgbuf.buf; 692 msg.msg_controllen = sizeof(cmsgbuf.buf); 693 694 n = recvmsg(fd, &msg, 0); 695 if (n == -1) { 696 switch (errno) { 697 case EAGAIN: 698 case EINTR: 699 goto err; 700 default: 701 lerr(1, "recvmsg"); 702 /* NOTREACHED */ 703 } 704 } 705 r->buflen = n; 706 707 /* check the packet */ 708 if (n < 5) { 709 /* not enough to be a real packet */ 710 goto err; 711 } 712 tp = (struct tftphdr *)r->buf; 713 switch (ntohs(tp->th_opcode)) { 714 case RRQ: 715 case WRQ: 716 break; 717 default: 718 goto err; 719 } 720 721 r->addrs.dst.ss_family = r->addrs.src.ss_family; 722 r->addrs.dst.ss_len = r->addrs.src.ss_len; 723 724 /* get local address if possible */ 725 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 726 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 727 if (l->cmsg2dst(cmsg, &r->addrs.dst) == -1) 728 goto err; 729 } 730 731 if (verbose) { 732 linfo("%s:%d -> %s:%d \"%s %s\"", 733 sock_ntop((struct sockaddr *)&r->addrs.src), 734 ntohs(((struct sockaddr_in *)&r->addrs.src)->sin_port), 735 sock_ntop((struct sockaddr *)&r->addrs.dst), 736 ntohs(((struct sockaddr_in *)&r->addrs.dst)->sin_port), 737 opcode(ntohs(tp->th_opcode)), tp->th_stuff); 738 /* XXX tp->th_stuff could be garbage */ 739 } 740 741 TAILQ_INSERT_TAIL(&child->fdrequests, r, entry); 742 evbuffer_add(child->buf, &r->addrs, sizeof(r->addrs)); 743 event_add(&child->push_ev, NULL); 744 745 return; 746 747 err: 748 free(r); 749 } 750 751 void 752 unprivproc_push(int fd, short events, void *arg) 753 { 754 if (evbuffer_write(child->buf, fd) == -1) 755 lerr(1, "child evbuffer_write"); 756 757 if (EVBUFFER_LENGTH(child->buf)) 758 event_add(&child->push_ev, NULL); 759 } 760 761 void 762 unprivproc_pop(int fd, short events, void *arg) 763 { 764 struct proxy_request *r; 765 766 struct msghdr msg; 767 union { 768 struct cmsghdr hdr; 769 char buf[CMSG_SPACE(sizeof(int))]; 770 } cmsgbuf; 771 struct cmsghdr *cmsg; 772 struct iovec iov; 773 struct src_addr *src_addr; 774 struct sockaddr_storage saddr; 775 socklen_t len; 776 int result; 777 int s; 778 779 len = sizeof(saddr); 780 781 do { 782 memset(&msg, 0, sizeof(msg)); 783 iov.iov_base = &result; 784 iov.iov_len = sizeof(int); 785 msg.msg_iov = &iov; 786 msg.msg_iovlen = 1; 787 msg.msg_control = &cmsgbuf.buf; 788 msg.msg_controllen = sizeof(cmsgbuf.buf); 789 790 switch (recvmsg(fd, &msg, 0)) { 791 case sizeof(int): 792 break; 793 794 case -1: 795 switch (errno) { 796 case EAGAIN: 797 case EINTR: 798 return; 799 default: 800 lerr(1, "child recvmsg"); 801 } 802 /* NOTREACHED */ 803 804 case 0: 805 lerrx(1, "privproc closed connection"); 806 807 default: 808 lerrx(1, "child recvmsg was weird"); 809 /* NOTREACHED */ 810 } 811 812 if (result != 0) { 813 errno = result; 814 lerr(1, "child fdpass fail"); 815 } 816 817 cmsg = CMSG_FIRSTHDR(&msg); 818 if (cmsg == NULL) 819 lerrx(1, "%s: no message header", __func__); 820 821 if (cmsg->cmsg_type != SCM_RIGHTS) { 822 lerrx(1, "%s: expected type %d got %d", __func__, 823 SCM_RIGHTS, cmsg->cmsg_type); 824 } 825 826 s = (*(int *)CMSG_DATA(cmsg)); 827 828 r = TAILQ_FIRST(&child->fdrequests); 829 if (r == NULL) 830 lerrx(1, "got fd without a pending request"); 831 832 TAILQ_REMOVE(&child->fdrequests, r, entry); 833 834 /* get ready to add rules */ 835 if (prepare_commit(r->id) == -1) 836 lerr(1, "%s: prepare_commit", __func__); 837 838 TAILQ_FOREACH(src_addr, &src_addrs, entry) 839 if (src_addr->addr.ss_family == r->addrs.dst.ss_family) 840 break; 841 if (src_addr == NULL) { 842 if (add_filter(r->id, PF_IN, (struct sockaddr *) 843 &r->addrs.dst, (struct sockaddr *)&r->addrs.src, 844 ntohs(((struct sockaddr_in *)&r->addrs.src) 845 ->sin_port), IPPROTO_UDP) == -1) 846 lerr(1, "%s: couldn't add pass in", __func__); 847 } else { 848 if (getsockname(s, (struct sockaddr*)&saddr, &len) == -1) 849 lerr(1, "%s: getsockname", __func__); 850 if (add_rdr(r->id, (struct sockaddr *)&r->addrs.dst, 851 (struct sockaddr*)&saddr, 852 ntohs(((struct sockaddr_in *)&saddr)->sin_port), 853 (struct sockaddr *)&r->addrs.src, 854 ntohs(((struct sockaddr_in *)&r->addrs.src)-> 855 sin_port), IPPROTO_UDP ) == -1) 856 lerr(1, "%s: couldn't add rdr rule", __func__); 857 } 858 859 if (add_filter(r->id, PF_OUT, (struct sockaddr *)&r->addrs.dst, 860 (struct sockaddr *)&r->addrs.src, 861 ntohs(((struct sockaddr_in *)&r->addrs.src)->sin_port), 862 IPPROTO_UDP) == -1) 863 lerr(1, "%s: couldn't add pass out", __func__); 864 865 if (do_commit() == -1) 866 lerr(1, "%s: couldn't commit rules", __func__); 867 868 /* forward the initial tftp request and start the insanity */ 869 if (sendto(s, r->buf, r->buflen, 0, 870 (struct sockaddr *)&r->addrs.dst, 871 r->addrs.dst.ss_len) == -1) 872 lerr(1, "%s: unable to send", __func__); 873 874 close(s); 875 876 evtimer_set(&r->ev, unprivproc_timeout, r); 877 evtimer_add(&r->ev, &transwait); 878 879 TAILQ_INSERT_TAIL(&child->tmrequests, r, entry); 880 } while (!TAILQ_EMPTY(&child->fdrequests)); 881 } 882 883 void 884 unprivproc_timeout(int fd, short events, void *arg) 885 { 886 struct proxy_request *r = arg; 887 888 TAILQ_REMOVE(&child->tmrequests, r, entry); 889 890 /* delete our rdr rule and clean up */ 891 prepare_commit(r->id); 892 do_commit(); 893 894 free(r); 895 } 896 897 898 const char * 899 opcode(int code) 900 { 901 static char str[6]; 902 903 switch (code) { 904 case 1: 905 (void)snprintf(str, sizeof(str), "RRQ"); 906 break; 907 case 2: 908 (void)snprintf(str, sizeof(str), "WRQ"); 909 break; 910 default: 911 (void)snprintf(str, sizeof(str), "(%d)", code); 912 break; 913 } 914 915 return (str); 916 } 917 918 const char * 919 sock_ntop(struct sockaddr *sa) 920 { 921 static int n = 0; 922 923 /* Cycle to next buffer. */ 924 n = (n + 1) % NTOP_BUFS; 925 ntop_buf[n][0] = '\0'; 926 927 if (sa->sa_family == AF_INET) { 928 struct sockaddr_in *sin = (struct sockaddr_in *)sa; 929 930 return (inet_ntop(AF_INET, &sin->sin_addr, ntop_buf[n], 931 sizeof ntop_buf[0])); 932 } 933 934 if (sa->sa_family == AF_INET6) { 935 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa; 936 937 return (inet_ntop(AF_INET6, &sin6->sin6_addr, ntop_buf[n], 938 sizeof ntop_buf[0])); 939 } 940 941 return (NULL); 942 } 943 944 void 945 syslog_vstrerror(int e, int priority, const char *fmt, va_list ap) 946 { 947 char *s; 948 949 if (vasprintf(&s, fmt, ap) == -1) { 950 syslog(LOG_EMERG, "unable to alloc in syslog_vstrerror"); 951 exit(1); 952 } 953 954 syslog(priority, "%s: %s", s, strerror(e)); 955 956 free(s); 957 } 958 959 void 960 syslog_err(int ecode, const char *fmt, ...) 961 { 962 va_list ap; 963 964 va_start(ap, fmt); 965 syslog_vstrerror(errno, LOG_EMERG, fmt, ap); 966 va_end(ap); 967 968 exit(ecode); 969 } 970 971 void 972 syslog_errx(int ecode, const char *fmt, ...) 973 { 974 va_list ap; 975 976 va_start(ap, fmt); 977 vsyslog(LOG_WARNING, fmt, ap); 978 va_end(ap); 979 980 exit(ecode); 981 } 982 983 void 984 syslog_warn(const char *fmt, ...) 985 { 986 va_list ap; 987 988 va_start(ap, fmt); 989 syslog_vstrerror(errno, LOG_WARNING, fmt, ap); 990 va_end(ap); 991 } 992 993 void 994 syslog_warnx(const char *fmt, ...) 995 { 996 va_list ap; 997 998 va_start(ap, fmt); 999 vsyslog(LOG_WARNING, fmt, ap); 1000 va_end(ap); 1001 } 1002 1003 void 1004 syslog_info(const char *fmt, ...) 1005 { 1006 va_list ap; 1007 1008 va_start(ap, fmt); 1009 vsyslog(LOG_INFO, fmt, ap); 1010 va_end(ap); 1011 } 1012 1013