1 /* 2 * Copyright (c) 1995, 1996, 1998 Theo de Raadt. All rights reserved. 3 * Copyright (c) 1983, 1993, 1994 4 * The Regents of the University of California. All rights reserved. 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 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * This product includes software developed by Theo de Raadt. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char *rcsid = "$OpenBSD: rcmd.c,v 1.35 2000/02/18 04:12:20 itojun Exp $"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <sys/param.h> 41 #include <sys/socket.h> 42 #include <sys/stat.h> 43 44 #include <netinet/in.h> 45 #include <arpa/inet.h> 46 47 #include <signal.h> 48 #include <fcntl.h> 49 #include <netdb.h> 50 #include <unistd.h> 51 #include <pwd.h> 52 #include <errno.h> 53 #include <stdio.h> 54 #include <ctype.h> 55 #include <string.h> 56 #include <syslog.h> 57 #include <stdlib.h> 58 #include <netgroup.h> 59 60 int __ivaliduser __P((FILE *, in_addr_t, const char *, const char *)); 61 int __ivaliduser_sa __P((FILE *, struct sockaddr *, const char *, const char *)); 62 static int __icheckhost __P((struct sockaddr *, const char *)); 63 static char *__gethostloop __P((struct sockaddr *)); 64 65 int 66 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 67 char **ahost; 68 in_port_t rport; 69 const char *locuser, *remuser, *cmd; 70 int *fd2p; 71 { 72 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 73 } 74 75 int 76 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 77 char **ahost; 78 in_port_t rport; 79 const char *locuser, *remuser, *cmd; 80 int *fd2p; 81 int af; 82 { 83 static char hbuf[MAXHOSTNAMELEN]; 84 char pbuf[NI_MAXSERV]; 85 struct addrinfo hints, *res, *r; 86 int error; 87 struct sockaddr_storage from; 88 fd_set *readsp = NULL; 89 int oldmask; 90 pid_t pid; 91 int s, lport, timo; 92 char c, *p; 93 int refused; 94 95 /* call rcmdsh() with specified remote shell if appropriate. */ 96 if (!issetugid() && (p = getenv("RSH"))) { 97 struct servent *sp = getservbyname("shell", "tcp"); 98 99 if (sp && sp->s_port == rport) 100 return (rcmdsh(ahost, rport, locuser, remuser, 101 cmd, p)); 102 } 103 104 /* use rsh(1) if non-root and remote port is shell. */ 105 if (geteuid()) { 106 struct servent *sp = getservbyname("shell", "tcp"); 107 108 if (sp && sp->s_port == rport) 109 return (rcmdsh(ahost, rport, locuser, remuser, 110 cmd, NULL)); 111 } 112 113 pid = getpid(); 114 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 115 memset(&hints, 0, sizeof(hints)); 116 hints.ai_family = af; 117 hints.ai_socktype = SOCK_STREAM; 118 hints.ai_flags = AI_CANONNAME; 119 error = getaddrinfo(*ahost, pbuf, &hints, &res); 120 if (error) { 121 #if 0 122 warnx("%s: %s", *ahost, gai_strerror(error)); 123 #endif 124 return (-1); 125 } 126 if (res->ai_canonname) { 127 strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1); 128 hbuf[sizeof(hbuf) - 1] = '\0'; 129 *ahost = hbuf; 130 } else 131 ; /*XXX*/ 132 133 r = res; 134 refused = 0; 135 oldmask = sigblock(sigmask(SIGURG)); 136 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 137 s = rresvport_af(&lport, r->ai_family); 138 if (s < 0) { 139 if (errno == EAGAIN) 140 (void)fprintf(stderr, 141 "rcmd: socket: All ports in use\n"); 142 else 143 (void)fprintf(stderr, "rcmd: socket: %s\n", 144 strerror(errno)); 145 if (r->ai_next) { 146 r = r->ai_next; 147 continue; 148 } else { 149 sigsetmask(oldmask); 150 freeaddrinfo(res); 151 return (-1); 152 } 153 } 154 fcntl(s, F_SETOWN, pid); 155 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 156 break; 157 (void)close(s); 158 if (errno == EADDRINUSE) { 159 lport--; 160 continue; 161 } 162 if (errno == ECONNREFUSED) 163 refused++; 164 if (r->ai_next) { 165 int oerrno = errno; 166 char hbuf[NI_MAXHOST]; 167 #ifdef NI_WITHSCOPEID 168 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 169 #else 170 const int niflags = NI_NUMERICHOST; 171 #endif 172 173 hbuf[0] = '\0'; 174 if (getnameinfo(r->ai_addr, r->ai_addrlen, 175 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 176 strcpy(hbuf, "(invalid)"); 177 (void)fprintf(stderr, "connect to address %s: ", hbuf); 178 errno = oerrno; 179 perror(0); 180 r = r->ai_next; 181 hbuf[0] = '\0'; 182 if (getnameinfo(r->ai_addr, r->ai_addrlen, 183 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 184 strcpy(hbuf, "(invalid)"); 185 (void)fprintf(stderr, "Trying %s...\n", hbuf); 186 continue; 187 } 188 if (refused && timo <= 16) { 189 (void)sleep(timo); 190 timo *= 2; 191 r = res; 192 refused = 0; 193 continue; 194 } 195 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 196 strerror(errno)); 197 sigsetmask(oldmask); 198 freeaddrinfo(res); 199 return (-1); 200 } 201 /* given "af" can be PF_UNSPEC, we need the real af for "s" */ 202 af = r->ai_family; 203 freeaddrinfo(res); 204 #if 0 205 /* 206 * try to rresvport() to the same port. This will make rresvport() 207 * fail it's first bind, resulting in it choosing a random port. 208 */ 209 lport--; 210 #endif 211 if (fd2p == 0) { 212 write(s, "", 1); 213 lport = 0; 214 } else { 215 char num[8]; 216 int s2 = rresvport_af(&lport, af), s3; 217 int len = sizeof(from); 218 int fdssize = howmany(MAX(s, s2)+1, NFDBITS) * sizeof(fd_mask); 219 220 if (s2 < 0) 221 goto bad; 222 readsp = (fd_set *)malloc(fdssize); 223 if (readsp == NULL) 224 goto bad; 225 listen(s2, 1); 226 (void)snprintf(num, sizeof(num), "%d", lport); 227 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 228 (void)fprintf(stderr, 229 "rcmd: write (setting up stderr): %s\n", 230 strerror(errno)); 231 (void)close(s2); 232 goto bad; 233 } 234 again: 235 bzero(readsp, fdssize); 236 FD_SET(s, readsp); 237 FD_SET(s2, readsp); 238 errno = 0; 239 if (select(MAX(s, s2) + 1, readsp, 0, 0, 0) < 1 || 240 !FD_ISSET(s2, readsp)) { 241 if (errno != 0) 242 (void)fprintf(stderr, 243 "rcmd: select (setting up stderr): %s\n", 244 strerror(errno)); 245 else 246 (void)fprintf(stderr, 247 "select: protocol failure in circuit setup\n"); 248 (void)close(s2); 249 goto bad; 250 } 251 s3 = accept(s2, (struct sockaddr *)&from, &len); 252 /* 253 * XXX careful for ftp bounce attacks. If discovered, shut them 254 * down and check for the real auxiliary channel to connect. 255 */ 256 switch (from.ss_family) { 257 case AF_INET: 258 case AF_INET6: 259 if (getnameinfo((struct sockaddr *)&from, len, 260 NULL, 0, num, sizeof(num), NI_NUMERICSERV) == 0 && 261 atoi(num) != 20) { 262 break; 263 } 264 close(s3); 265 goto again; 266 default: 267 break; 268 } 269 (void)close(s2); 270 if (s3 < 0) { 271 (void)fprintf(stderr, 272 "rcmd: accept: %s\n", strerror(errno)); 273 lport = 0; 274 goto bad; 275 } 276 *fd2p = s3; 277 switch (from.ss_family) { 278 case AF_INET: 279 case AF_INET6: 280 if (getnameinfo((struct sockaddr *)&from, len, 281 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 || 282 (atoi(num) >= IPPORT_RESERVED || 283 atoi(num) < IPPORT_RESERVED / 2)) { 284 (void)fprintf(stderr, 285 "socket: protocol failure in circuit setup.\n"); 286 goto bad2; 287 } 288 break; 289 default: 290 break; 291 } 292 } 293 (void)write(s, locuser, strlen(locuser)+1); 294 (void)write(s, remuser, strlen(remuser)+1); 295 (void)write(s, cmd, strlen(cmd)+1); 296 if (read(s, &c, 1) != 1) { 297 (void)fprintf(stderr, 298 "rcmd: %s: %s\n", *ahost, strerror(errno)); 299 goto bad2; 300 } 301 if (c != 0) { 302 while (read(s, &c, 1) == 1) { 303 (void)write(STDERR_FILENO, &c, 1); 304 if (c == '\n') 305 break; 306 } 307 goto bad2; 308 } 309 sigsetmask(oldmask); 310 free(readsp); 311 return (s); 312 bad2: 313 if (lport) 314 (void)close(*fd2p); 315 bad: 316 if (readsp) 317 free(readsp); 318 (void)close(s); 319 sigsetmask(oldmask); 320 return (-1); 321 } 322 323 int __check_rhosts_file = 1; 324 char *__rcmd_errstr; 325 326 int 327 ruserok(rhost, superuser, ruser, luser) 328 const char *rhost, *ruser, *luser; 329 int superuser; 330 { 331 struct addrinfo hints, *res, *r; 332 int error; 333 334 memset(&hints, 0, sizeof(hints)); 335 hints.ai_family = PF_UNSPEC; 336 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 337 error = getaddrinfo(rhost, "0", &hints, &res); 338 if (error) 339 return (-1); 340 341 for (r = res; r; r = r->ai_next) { 342 if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser, 343 luser) == 0) { 344 freeaddrinfo(res); 345 return (0); 346 } 347 } 348 freeaddrinfo(res); 349 return (-1); 350 } 351 352 /* 353 * New .rhosts strategy: We are passed an ip address. We spin through 354 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 355 * has ip addresses, we don't have to trust a nameserver. When it 356 * contains hostnames, we spin through the list of addresses the nameserver 357 * gives us and look for a match. 358 * 359 * Returns 0 if ok, -1 if not ok. 360 */ 361 int 362 iruserok(raddr, superuser, ruser, luser) 363 u_int32_t raddr; 364 int superuser; 365 const char *ruser, *luser; 366 { 367 struct sockaddr_in sin; 368 369 memset(&sin, 0, sizeof(sin)); 370 sin.sin_family = AF_INET; 371 sin.sin_len = sizeof(struct sockaddr_in); 372 memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr)); 373 return iruserok_sa(&sin, sizeof(struct sockaddr_in), superuser, ruser, 374 luser); 375 } 376 377 int 378 iruserok_sa(raddr, rlen, superuser, ruser, luser) 379 const void *raddr; 380 int rlen; 381 int superuser; 382 const char *ruser, *luser; 383 { 384 struct sockaddr *sa; 385 register char *cp; 386 struct stat sbuf; 387 struct passwd *pwd; 388 FILE *hostf; 389 uid_t uid; 390 int first; 391 char pbuf[MAXPATHLEN]; 392 393 sa = (struct sockaddr *)raddr; 394 #ifdef lint 395 rlen = rlen; 396 #endif 397 first = 1; 398 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 399 again: 400 if (hostf) { 401 if (__ivaliduser_sa(hostf, sa, luser, ruser) == 0) { 402 (void)fclose(hostf); 403 return (0); 404 } 405 (void)fclose(hostf); 406 } 407 if (first == 1 && (__check_rhosts_file || superuser)) { 408 first = 0; 409 if ((pwd = getpwnam(luser)) == NULL) 410 return (-1); 411 (void)strcpy(pbuf, pwd->pw_dir); 412 (void)strcat(pbuf, "/.rhosts"); 413 414 /* 415 * Change effective uid while opening .rhosts. If root and 416 * reading an NFS mounted file system, can't read files that 417 * are protected read/write owner only. 418 */ 419 uid = geteuid(); 420 (void)seteuid(pwd->pw_uid); 421 hostf = fopen(pbuf, "r"); 422 (void)seteuid(uid); 423 424 if (hostf == NULL) 425 return (-1); 426 /* 427 * If not a regular file, or is owned by someone other than 428 * user or root or if writeable by anyone but the owner, quit. 429 */ 430 cp = NULL; 431 if (lstat(pbuf, &sbuf) < 0) 432 cp = ".rhosts lstat failed"; 433 else if (!S_ISREG(sbuf.st_mode)) 434 cp = ".rhosts not regular file"; 435 else if (fstat(fileno(hostf), &sbuf) < 0) 436 cp = ".rhosts fstat failed"; 437 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 438 cp = "bad .rhosts owner"; 439 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 440 cp = ".rhosts writeable by other than owner"; 441 /* If there were any problems, quit. */ 442 if (cp) { 443 __rcmd_errstr = cp; 444 (void)fclose(hostf); 445 return (-1); 446 } 447 goto again; 448 } 449 return (-1); 450 } 451 452 /* 453 * XXX 454 * Don't make static, used by lpd(8). 455 * 456 * Returns 0 if ok, -1 if not ok. 457 */ 458 int 459 __ivaliduser(hostf, raddrl, luser, ruser) 460 FILE *hostf; 461 in_addr_t raddrl; 462 const char *luser, *ruser; 463 { 464 struct sockaddr_in sin; 465 466 memset(&sin, 0, sizeof(sin)); 467 sin.sin_family = AF_INET; 468 sin.sin_len = sizeof(struct sockaddr_in); 469 memcpy(&sin.sin_addr, &raddrl, sizeof(sin.sin_addr)); 470 return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, luser, ruser); 471 } 472 473 int 474 __ivaliduser_sa(hostf, raddr, luser, ruser) 475 FILE *hostf; 476 struct sockaddr *raddr; 477 const char *luser, *ruser; 478 { 479 register char *user, *p; 480 char *buf; 481 const char *auser, *ahost; 482 int hostok, userok; 483 char *rhost = (char *)-1; 484 char domain[MAXHOSTNAMELEN]; 485 size_t buflen; 486 487 getdomainname(domain, sizeof(domain)); 488 489 while ((buf = fgetln(hostf, &buflen))) { 490 p = buf; 491 if (*p == '#') 492 continue; 493 while (*p != '\n' && *p != ' ' && *p != '\t' && p < buf + buflen) { 494 if (!isprint(*p)) 495 goto bail; 496 *p = isupper(*p) ? tolower(*p) : *p; 497 p++; 498 } 499 if (p >= buf + buflen) 500 continue; 501 if (*p == ' ' || *p == '\t') { 502 *p++ = '\0'; 503 while ((*p == ' ' || *p == '\t') && p < buf + buflen) 504 p++; 505 if (p >= buf + buflen) 506 continue; 507 user = p; 508 while (*p != '\n' && *p != ' ' && 509 *p != '\t' && p < buf + buflen) { 510 if (!isprint(*p)) 511 goto bail; 512 p++; 513 } 514 } else 515 user = p; 516 *p = '\0'; 517 518 if (p == buf) 519 continue; 520 521 auser = *user ? user : luser; 522 ahost = buf; 523 524 if (strlen(ahost) >= MAXHOSTNAMELEN) 525 continue; 526 527 /* 528 * innetgr() must lookup a hostname (we do not attempt 529 * to change the semantics so that netgroups may have 530 * #.#.#.# addresses in the list.) 531 */ 532 if (ahost[0] == '+') 533 switch (ahost[1]) { 534 case '\0': 535 hostok = 1; 536 break; 537 case '@': 538 if (rhost == (char *)-1) 539 rhost = __gethostloop(raddr); 540 hostok = 0; 541 if (rhost) 542 hostok = innetgr(&ahost[2], rhost, 543 NULL, domain); 544 break; 545 default: 546 hostok = __icheckhost(raddr, &ahost[1]); 547 break; 548 } 549 else if (ahost[0] == '-') 550 switch (ahost[1]) { 551 case '\0': 552 hostok = -1; 553 break; 554 case '@': 555 if (rhost == (char *)-1) 556 rhost = __gethostloop(raddr); 557 hostok = 0; 558 if (rhost) 559 hostok = -innetgr(&ahost[2], rhost, 560 NULL, domain); 561 break; 562 default: 563 hostok = -__icheckhost(raddr, &ahost[1]); 564 break; 565 } 566 else 567 hostok = __icheckhost(raddr, ahost); 568 569 570 if (auser[0] == '+') 571 switch (auser[1]) { 572 case '\0': 573 userok = 1; 574 break; 575 case '@': 576 userok = innetgr(&auser[2], NULL, ruser, 577 domain); 578 break; 579 default: 580 userok = strcmp(ruser, &auser[1]) ? 0 : 1; 581 break; 582 } 583 else if (auser[0] == '-') 584 switch (auser[1]) { 585 case '\0': 586 userok = -1; 587 break; 588 case '@': 589 userok = -innetgr(&auser[2], NULL, ruser, 590 domain); 591 break; 592 default: 593 userok = strcmp(ruser, &auser[1]) ? 0 : -1; 594 break; 595 } 596 else 597 userok = strcmp(ruser, auser) ? 0 : 1; 598 599 /* Check if one component did not match */ 600 if (hostok == 0 || userok == 0) 601 continue; 602 603 /* Check if we got a forbidden pair */ 604 if (userok <= -1 || hostok <= -1) 605 return (-1); 606 607 /* Check if we got a valid pair */ 608 if (hostok >= 1 && userok >= 1) 609 return (0); 610 } 611 bail: 612 return (-1); 613 } 614 615 /* 616 * Returns "true" if match, 0 if no match. If we do not find any 617 * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work. 618 * 619 * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion 620 * if af == AF_INET6. 621 */ 622 static int 623 __icheckhost(raddr, lhost) 624 struct sockaddr *raddr; 625 const char *lhost; 626 { 627 struct addrinfo hints, *res, *r; 628 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 629 int error; 630 #ifdef NI_WITHSCOPEID 631 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 632 #else 633 const int niflags = NI_NUMERICHOST; 634 #endif 635 636 h1[0] = '\0'; 637 if (getnameinfo(raddr, raddr->sa_len, h1, sizeof(h1), NULL, 0, 638 niflags) != 0) 639 return (0); 640 641 /* Resolve laddr into sockaddr */ 642 memset(&hints, 0, sizeof(hints)); 643 hints.ai_family = raddr->sa_family; 644 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 645 res = NULL; 646 error = getaddrinfo(lhost, "0", &hints, &res); 647 if (error) 648 return (0); 649 650 /* 651 * Try string comparisons between raddr and laddr. 652 */ 653 for (r = res; r; r = r->ai_next) { 654 h2[0] = '\0'; 655 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 656 NULL, 0, niflags) != 0) 657 continue; 658 if (strcmp(h1, h2) == 0) { 659 freeaddrinfo(res); 660 return (1); 661 } 662 } 663 664 /* No match. */ 665 freeaddrinfo(res); 666 return (0); 667 } 668 669 /* 670 * Return the hostname associated with the supplied address. 671 * Do a reverse lookup as well for security. If a loop cannot 672 * be found, pack the result of inet_ntoa() into the string. 673 * 674 * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion 675 * if af == AF_INET6. 676 */ 677 static char * 678 __gethostloop(raddr) 679 struct sockaddr *raddr; 680 { 681 static char remotehost[NI_MAXHOST]; 682 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 683 struct addrinfo hints, *res, *r; 684 int error; 685 #ifdef NI_WITHSCOPEID 686 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 687 #else 688 const int niflags = NI_NUMERICHOST; 689 #endif 690 691 h1[0] = remotehost[0] = '\0'; 692 if (getnameinfo(raddr, raddr->sa_len, remotehost, sizeof(remotehost), 693 NULL, 0, NI_NAMEREQD) != 0) 694 return (NULL); 695 if (getnameinfo(raddr, raddr->sa_len, h1, sizeof(h1), NULL, 0, 696 niflags) != 0) 697 return (NULL); 698 699 /* 700 * Look up the name and check that the supplied 701 * address is in the list 702 */ 703 memset(&hints, 0, sizeof(hints)); 704 hints.ai_family = raddr->sa_family; 705 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 706 hints.ai_flags = AI_CANONNAME; 707 res = NULL; 708 error = getaddrinfo(remotehost, "0", &hints, &res); 709 if (error) 710 return (NULL); 711 712 for (r = res; r; r = r->ai_next) { 713 h2[0] = '\0'; 714 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 715 NULL, 0, niflags) != 0) 716 continue; 717 if (strcmp(h1, h2) == 0) { 718 freeaddrinfo(res); 719 return (remotehost); 720 } 721 } 722 723 /* 724 * either the DNS adminstrator has made a configuration 725 * mistake, or someone has attempted to spoof us 726 */ 727 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 728 h1, res->ai_canonname ? res->ai_canonname : remotehost); 729 freeaddrinfo(res); 730 return (NULL); 731 } 732