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 1.33 2000/01/27 05:18:47 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 94 /* call rcmdsh() with specified remote shell if appropriate. */ 95 if (!issetugid() && (p = getenv("RSH"))) { 96 struct servent *sp = getservbyname("shell", "tcp"); 97 98 if (sp && sp->s_port == rport) 99 return (rcmdsh(ahost, rport, locuser, remuser, 100 cmd, p)); 101 } 102 103 /* use rsh(1) if non-root and remote port is shell. */ 104 if (geteuid()) { 105 struct servent *sp = getservbyname("shell", "tcp"); 106 107 if (sp && sp->s_port == rport) 108 return (rcmdsh(ahost, rport, locuser, remuser, 109 cmd, NULL)); 110 } 111 112 pid = getpid(); 113 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 114 memset(&hints, 0, sizeof(hints)); 115 hints.ai_family = af; 116 hints.ai_socktype = SOCK_STREAM; 117 hints.ai_flags = AI_CANONNAME; 118 error = getaddrinfo(*ahost, pbuf, &hints, &res); 119 if (error) { 120 #if 0 121 warnx("%s: %s", *ahost, gai_strerror(error)); 122 #endif 123 return (-1); 124 } 125 if (res->ai_canonname) { 126 strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1); 127 hbuf[sizeof(hbuf) - 1] = '\0'; 128 *ahost = hbuf; 129 } else 130 ; /*XXX*/ 131 132 r = res; 133 oldmask = sigblock(sigmask(SIGURG)); 134 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 135 s = rresvport_af(&lport, r->ai_family); 136 if (s < 0) { 137 if (errno == EAGAIN) 138 (void)fprintf(stderr, 139 "rcmd: socket: All ports in use\n"); 140 else 141 (void)fprintf(stderr, "rcmd: socket: %s\n", 142 strerror(errno)); 143 sigsetmask(oldmask); 144 freeaddrinfo(res); 145 return (-1); 146 } 147 fcntl(s, F_SETOWN, pid); 148 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 149 break; 150 (void)close(s); 151 if (errno == EADDRINUSE) { 152 lport--; 153 continue; 154 } 155 if (errno == ECONNREFUSED && timo <= 16) { 156 (void)sleep(timo); 157 timo *= 2; 158 continue; 159 } 160 if (r->ai_next) { 161 int oerrno = errno; 162 char hbuf[NI_MAXHOST]; 163 #ifdef NI_WITHSCOPEID 164 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 165 #else 166 const int niflags = NI_NUMERICHOST; 167 #endif 168 169 hbuf[0] = '\0'; 170 if (getnameinfo(r->ai_addr, r->ai_addrlen, 171 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 172 strcpy(hbuf, "(invalid)"); 173 (void)fprintf(stderr, "connect to address %s: ", hbuf); 174 errno = oerrno; 175 perror(0); 176 r = r->ai_next; 177 hbuf[0] = '\0'; 178 if (getnameinfo(r->ai_addr, r->ai_addrlen, 179 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 180 strcpy(hbuf, "(invalid)"); 181 (void)fprintf(stderr, "Trying %s...\n", hbuf); 182 continue; 183 } 184 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 185 strerror(errno)); 186 sigsetmask(oldmask); 187 freeaddrinfo(res); 188 return (-1); 189 } 190 /* given "af" can be PF_UNSPEC, we need the real af for "s" */ 191 af = r->ai_family; 192 freeaddrinfo(res); 193 #if 0 194 /* 195 * try to rresvport() to the same port. This will make rresvport() 196 * fail it's first bind, resulting in it choosing a random port. 197 */ 198 lport--; 199 #endif 200 if (fd2p == 0) { 201 write(s, "", 1); 202 lport = 0; 203 } else { 204 char num[8]; 205 int s2 = rresvport_af(&lport, af), s3; 206 int len = sizeof(from); 207 int fdssize = howmany(MAX(s, s2)+1, NFDBITS) * sizeof(fd_mask); 208 209 if (s2 < 0) 210 goto bad; 211 readsp = (fd_set *)malloc(fdssize); 212 if (readsp == NULL) 213 goto bad; 214 listen(s2, 1); 215 (void)snprintf(num, sizeof(num), "%d", lport); 216 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 217 (void)fprintf(stderr, 218 "rcmd: write (setting up stderr): %s\n", 219 strerror(errno)); 220 (void)close(s2); 221 goto bad; 222 } 223 again: 224 bzero(readsp, fdssize); 225 FD_SET(s, readsp); 226 FD_SET(s2, readsp); 227 errno = 0; 228 if (select(MAX(s, s2) + 1, readsp, 0, 0, 0) < 1 || 229 !FD_ISSET(s2, readsp)) { 230 if (errno != 0) 231 (void)fprintf(stderr, 232 "rcmd: select (setting up stderr): %s\n", 233 strerror(errno)); 234 else 235 (void)fprintf(stderr, 236 "select: protocol failure in circuit setup\n"); 237 (void)close(s2); 238 goto bad; 239 } 240 s3 = accept(s2, (struct sockaddr *)&from, &len); 241 /* 242 * XXX careful for ftp bounce attacks. If discovered, shut them 243 * down and check for the real auxiliary channel to connect. 244 */ 245 switch (from.ss_family) { 246 case AF_INET: 247 case AF_INET6: 248 if (getnameinfo((struct sockaddr *)&from, len, 249 NULL, 0, num, sizeof(num), NI_NUMERICSERV) == 0 && 250 atoi(num) != 20) { 251 break; 252 } 253 close(s3); 254 goto again; 255 default: 256 break; 257 } 258 (void)close(s2); 259 if (s3 < 0) { 260 (void)fprintf(stderr, 261 "rcmd: accept: %s\n", strerror(errno)); 262 lport = 0; 263 goto bad; 264 } 265 *fd2p = s3; 266 switch (from.ss_family) { 267 case AF_INET: 268 case AF_INET6: 269 if (getnameinfo((struct sockaddr *)&from, len, 270 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 || 271 (atoi(num) >= IPPORT_RESERVED || 272 atoi(num) < IPPORT_RESERVED / 2)) { 273 (void)fprintf(stderr, 274 "socket: protocol failure in circuit setup.\n"); 275 goto bad2; 276 } 277 break; 278 default: 279 break; 280 } 281 } 282 (void)write(s, locuser, strlen(locuser)+1); 283 (void)write(s, remuser, strlen(remuser)+1); 284 (void)write(s, cmd, strlen(cmd)+1); 285 if (read(s, &c, 1) != 1) { 286 (void)fprintf(stderr, 287 "rcmd: %s: %s\n", *ahost, strerror(errno)); 288 goto bad2; 289 } 290 if (c != 0) { 291 while (read(s, &c, 1) == 1) { 292 (void)write(STDERR_FILENO, &c, 1); 293 if (c == '\n') 294 break; 295 } 296 goto bad2; 297 } 298 sigsetmask(oldmask); 299 free(readsp); 300 return (s); 301 bad2: 302 if (lport) 303 (void)close(*fd2p); 304 bad: 305 if (readsp) 306 free(readsp); 307 (void)close(s); 308 sigsetmask(oldmask); 309 return (-1); 310 } 311 312 int __check_rhosts_file = 1; 313 char *__rcmd_errstr; 314 315 int 316 ruserok(rhost, superuser, ruser, luser) 317 const char *rhost, *ruser, *luser; 318 int superuser; 319 { 320 struct addrinfo hints, *res, *r; 321 int error; 322 323 memset(&hints, 0, sizeof(hints)); 324 hints.ai_family = PF_UNSPEC; 325 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 326 error = getaddrinfo(rhost, "0", &hints, &res); 327 if (error) 328 return (-1); 329 330 for (r = res; r; r = r->ai_next) { 331 if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser, 332 luser) == 0) { 333 freeaddrinfo(res); 334 return (0); 335 } 336 } 337 freeaddrinfo(res); 338 return (-1); 339 } 340 341 /* 342 * New .rhosts strategy: We are passed an ip address. We spin through 343 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 344 * has ip addresses, we don't have to trust a nameserver. When it 345 * contains hostnames, we spin through the list of addresses the nameserver 346 * gives us and look for a match. 347 * 348 * Returns 0 if ok, -1 if not ok. 349 */ 350 int 351 iruserok(raddr, superuser, ruser, luser) 352 u_int32_t raddr; 353 int superuser; 354 const char *ruser, *luser; 355 { 356 struct sockaddr_in sin; 357 358 memset(&sin, 0, sizeof(sin)); 359 sin.sin_family = AF_INET; 360 sin.sin_len = sizeof(struct sockaddr_in); 361 memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr)); 362 return iruserok_sa(&sin, sizeof(struct sockaddr_in), superuser, ruser, 363 luser); 364 } 365 366 int 367 iruserok_sa(raddr, rlen, superuser, ruser, luser) 368 const void *raddr; 369 int rlen; 370 int superuser; 371 const char *ruser, *luser; 372 { 373 struct sockaddr *sa; 374 register char *cp; 375 struct stat sbuf; 376 struct passwd *pwd; 377 FILE *hostf; 378 uid_t uid; 379 int first; 380 char pbuf[MAXPATHLEN]; 381 382 sa = (struct sockaddr *)raddr; 383 #ifdef lint 384 rlen = rlen; 385 #endif 386 first = 1; 387 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 388 again: 389 if (hostf) { 390 if (__ivaliduser_sa(hostf, sa, luser, ruser) == 0) { 391 (void)fclose(hostf); 392 return (0); 393 } 394 (void)fclose(hostf); 395 } 396 if (first == 1 && (__check_rhosts_file || superuser)) { 397 first = 0; 398 if ((pwd = getpwnam(luser)) == NULL) 399 return (-1); 400 (void)strcpy(pbuf, pwd->pw_dir); 401 (void)strcat(pbuf, "/.rhosts"); 402 403 /* 404 * Change effective uid while opening .rhosts. If root and 405 * reading an NFS mounted file system, can't read files that 406 * are protected read/write owner only. 407 */ 408 uid = geteuid(); 409 (void)seteuid(pwd->pw_uid); 410 hostf = fopen(pbuf, "r"); 411 (void)seteuid(uid); 412 413 if (hostf == NULL) 414 return (-1); 415 /* 416 * If not a regular file, or is owned by someone other than 417 * user or root or if writeable by anyone but the owner, quit. 418 */ 419 cp = NULL; 420 if (lstat(pbuf, &sbuf) < 0) 421 cp = ".rhosts lstat failed"; 422 else if (!S_ISREG(sbuf.st_mode)) 423 cp = ".rhosts not regular file"; 424 else if (fstat(fileno(hostf), &sbuf) < 0) 425 cp = ".rhosts fstat failed"; 426 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 427 cp = "bad .rhosts owner"; 428 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 429 cp = ".rhosts writeable by other than owner"; 430 /* If there were any problems, quit. */ 431 if (cp) { 432 __rcmd_errstr = cp; 433 (void)fclose(hostf); 434 return (-1); 435 } 436 goto again; 437 } 438 return (-1); 439 } 440 441 /* 442 * XXX 443 * Don't make static, used by lpd(8). 444 * 445 * Returns 0 if ok, -1 if not ok. 446 */ 447 int 448 __ivaliduser(hostf, raddrl, luser, ruser) 449 FILE *hostf; 450 in_addr_t raddrl; 451 const char *luser, *ruser; 452 { 453 struct sockaddr_in sin; 454 455 memset(&sin, 0, sizeof(sin)); 456 sin.sin_family = AF_INET; 457 sin.sin_len = sizeof(struct sockaddr_in); 458 memcpy(&sin.sin_addr, &raddrl, sizeof(sin.sin_addr)); 459 return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, luser, ruser); 460 } 461 462 int 463 __ivaliduser_sa(hostf, raddr, luser, ruser) 464 FILE *hostf; 465 struct sockaddr *raddr; 466 const char *luser, *ruser; 467 { 468 register char *user, *p; 469 char *buf; 470 const char *auser, *ahost; 471 int hostok, userok; 472 char *rhost = (char *)-1; 473 char domain[MAXHOSTNAMELEN]; 474 size_t buflen; 475 476 getdomainname(domain, sizeof(domain)); 477 478 while ((buf = fgetln(hostf, &buflen))) { 479 p = buf; 480 if (*p == '#') 481 continue; 482 while (*p != '\n' && *p != ' ' && *p != '\t' && p < buf + buflen) { 483 if (!isprint(*p)) 484 goto bail; 485 *p = isupper(*p) ? tolower(*p) : *p; 486 p++; 487 } 488 if (p >= buf + buflen) 489 continue; 490 if (*p == ' ' || *p == '\t') { 491 *p++ = '\0'; 492 while ((*p == ' ' || *p == '\t') && p < buf + buflen) 493 p++; 494 if (p >= buf + buflen) 495 continue; 496 user = p; 497 while (*p != '\n' && *p != ' ' && 498 *p != '\t' && p < buf + buflen) { 499 if (!isprint(*p)) 500 goto bail; 501 p++; 502 } 503 } else 504 user = p; 505 *p = '\0'; 506 507 if (p == buf) 508 continue; 509 510 auser = *user ? user : luser; 511 ahost = buf; 512 513 if (strlen(ahost) >= MAXHOSTNAMELEN) 514 continue; 515 516 /* 517 * innetgr() must lookup a hostname (we do not attempt 518 * to change the semantics so that netgroups may have 519 * #.#.#.# addresses in the list.) 520 */ 521 if (ahost[0] == '+') 522 switch (ahost[1]) { 523 case '\0': 524 hostok = 1; 525 break; 526 case '@': 527 if (rhost == (char *)-1) 528 rhost = __gethostloop(raddr); 529 hostok = 0; 530 if (rhost) 531 hostok = innetgr(&ahost[2], rhost, 532 NULL, domain); 533 break; 534 default: 535 hostok = __icheckhost(raddr, &ahost[1]); 536 break; 537 } 538 else if (ahost[0] == '-') 539 switch (ahost[1]) { 540 case '\0': 541 hostok = -1; 542 break; 543 case '@': 544 if (rhost == (char *)-1) 545 rhost = __gethostloop(raddr); 546 hostok = 0; 547 if (rhost) 548 hostok = -innetgr(&ahost[2], rhost, 549 NULL, domain); 550 break; 551 default: 552 hostok = -__icheckhost(raddr, &ahost[1]); 553 break; 554 } 555 else 556 hostok = __icheckhost(raddr, ahost); 557 558 559 if (auser[0] == '+') 560 switch (auser[1]) { 561 case '\0': 562 userok = 1; 563 break; 564 case '@': 565 userok = innetgr(&auser[2], NULL, ruser, 566 domain); 567 break; 568 default: 569 userok = strcmp(ruser, &auser[1]) ? 0 : 1; 570 break; 571 } 572 else if (auser[0] == '-') 573 switch (auser[1]) { 574 case '\0': 575 userok = -1; 576 break; 577 case '@': 578 userok = -innetgr(&auser[2], NULL, ruser, 579 domain); 580 break; 581 default: 582 userok = strcmp(ruser, &auser[1]) ? 0 : -1; 583 break; 584 } 585 else 586 userok = strcmp(ruser, auser) ? 0 : 1; 587 588 /* Check if one component did not match */ 589 if (hostok == 0 || userok == 0) 590 continue; 591 592 /* Check if we got a forbidden pair */ 593 if (userok <= -1 || hostok <= -1) 594 return (-1); 595 596 /* Check if we got a valid pair */ 597 if (hostok >= 1 && userok >= 1) 598 return (0); 599 } 600 bail: 601 return (-1); 602 } 603 604 /* 605 * Returns "true" if match, 0 if no match. If we do not find any 606 * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work. 607 * 608 * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion 609 * if af == AF_INET6. 610 */ 611 static int 612 __icheckhost(raddr, lhost) 613 struct sockaddr *raddr; 614 const char *lhost; 615 { 616 struct addrinfo hints, *res, *r; 617 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 618 int error; 619 #ifdef NI_WITHSCOPEID 620 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 621 #else 622 const int niflags = NI_NUMERICHOST; 623 #endif 624 625 h1[0] = '\0'; 626 if (getnameinfo(raddr, raddr->sa_len, h1, sizeof(h1), NULL, 0, 627 niflags) != 0) 628 return (0); 629 630 /* Resolve laddr into sockaddr */ 631 memset(&hints, 0, sizeof(hints)); 632 hints.ai_family = raddr->sa_family; 633 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 634 res = NULL; 635 error = getaddrinfo(lhost, "0", &hints, &res); 636 if (error) 637 return (0); 638 639 /* 640 * Try string comparisons between raddr and laddr. 641 */ 642 for (r = res; r; r = r->ai_next) { 643 h2[0] = '\0'; 644 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 645 NULL, 0, niflags) != 0) 646 continue; 647 if (strcmp(h1, h2) == 0) { 648 freeaddrinfo(res); 649 return (1); 650 } 651 } 652 653 /* No match. */ 654 freeaddrinfo(res); 655 return (0); 656 } 657 658 /* 659 * Return the hostname associated with the supplied address. 660 * Do a reverse lookup as well for security. If a loop cannot 661 * be found, pack the result of inet_ntoa() into the string. 662 * 663 * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion 664 * if af == AF_INET6. 665 */ 666 static char * 667 __gethostloop(raddr) 668 struct sockaddr *raddr; 669 { 670 static char remotehost[NI_MAXHOST]; 671 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 672 struct addrinfo hints, *res, *r; 673 int error; 674 #ifdef NI_WITHSCOPEID 675 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 676 #else 677 const int niflags = NI_NUMERICHOST; 678 #endif 679 680 h1[0] = remotehost[0] = '\0'; 681 if (getnameinfo(raddr, raddr->sa_len, remotehost, sizeof(remotehost), 682 NULL, 0, NI_NAMEREQD) != 0) 683 return (NULL); 684 if (getnameinfo(raddr, raddr->sa_len, h1, sizeof(h1), NULL, 0, 685 niflags) != 0) 686 return (NULL); 687 688 /* 689 * Look up the name and check that the supplied 690 * address is in the list 691 */ 692 memset(&hints, 0, sizeof(hints)); 693 hints.ai_family = raddr->sa_family; 694 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 695 hints.ai_flags = AI_CANONNAME; 696 res = NULL; 697 error = getaddrinfo(remotehost, "0", &hints, &res); 698 if (error) 699 return (NULL); 700 701 for (r = res; r; r = r->ai_next) { 702 h2[0] = '\0'; 703 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 704 NULL, 0, niflags) != 0) 705 continue; 706 if (strcmp(h1, h2) == 0) { 707 freeaddrinfo(res); 708 return (remotehost); 709 } 710 } 711 712 /* 713 * either the DNS adminstrator has made a configuration 714 * mistake, or someone has attempted to spoof us 715 */ 716 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 717 h1, res->ai_canonname ? res->ai_canonname : remotehost); 718 freeaddrinfo(res); 719 return (NULL); 720 } 721