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 1.38 2001/06/27 00:58:55 lebel 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 *, socklen_t, 62 const char *, const char *)); 63 static int __icheckhost __P((struct sockaddr *, socklen_t, const char *)); 64 static char *__gethostloop __P((struct sockaddr *, socklen_t)); 65 66 int 67 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 68 char **ahost; 69 in_port_t rport; 70 const char *locuser, *remuser, *cmd; 71 int *fd2p; 72 { 73 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 74 } 75 76 int 77 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 78 char **ahost; 79 in_port_t rport; 80 const char *locuser, *remuser, *cmd; 81 int *fd2p; 82 int af; 83 { 84 static char hbuf[MAXHOSTNAMELEN]; 85 char pbuf[NI_MAXSERV]; 86 struct addrinfo hints, *res, *r; 87 int error; 88 struct sockaddr_storage from; 89 fd_set *readsp = NULL; 90 int oldmask; 91 pid_t pid; 92 int s, lport, timo; 93 char c, *p; 94 int refused; 95 96 /* call rcmdsh() with specified remote shell if appropriate. */ 97 if (!issetugid() && (p = getenv("RSH")) && *p) { 98 struct servent *sp = getservbyname("shell", "tcp"); 99 100 if (sp && sp->s_port == rport) 101 return (rcmdsh(ahost, rport, locuser, remuser, 102 cmd, p)); 103 } 104 105 /* use rsh(1) if non-root and remote port is shell. */ 106 if (geteuid()) { 107 struct servent *sp = getservbyname("shell", "tcp"); 108 109 if (sp && sp->s_port == rport) 110 return (rcmdsh(ahost, rport, locuser, remuser, 111 cmd, NULL)); 112 } 113 114 pid = getpid(); 115 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 116 memset(&hints, 0, sizeof(hints)); 117 hints.ai_family = af; 118 hints.ai_socktype = SOCK_STREAM; 119 hints.ai_flags = AI_CANONNAME; 120 error = getaddrinfo(*ahost, pbuf, &hints, &res); 121 if (error) { 122 #if 0 123 warnx("%s: %s", *ahost, gai_strerror(error)); 124 #endif 125 return (-1); 126 } 127 if (res->ai_canonname) { 128 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 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 first = 1; 395 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 396 again: 397 if (hostf) { 398 if (__ivaliduser_sa(hostf, sa, rlen, luser, ruser) == 0) { 399 (void)fclose(hostf); 400 return (0); 401 } 402 (void)fclose(hostf); 403 } 404 if (first == 1 && (__check_rhosts_file || superuser)) { 405 first = 0; 406 if ((pwd = getpwnam(luser)) == NULL) 407 return (-1); 408 (void)strcpy(pbuf, pwd->pw_dir); 409 (void)strcat(pbuf, "/.rhosts"); 410 411 /* 412 * Change effective uid while opening .rhosts. If root and 413 * reading an NFS mounted file system, can't read files that 414 * are protected read/write owner only. 415 */ 416 uid = geteuid(); 417 (void)seteuid(pwd->pw_uid); 418 hostf = fopen(pbuf, "r"); 419 (void)seteuid(uid); 420 421 if (hostf == NULL) 422 return (-1); 423 /* 424 * If not a regular file, or is owned by someone other than 425 * user or root or if writeable by anyone but the owner, quit. 426 */ 427 cp = NULL; 428 if (lstat(pbuf, &sbuf) < 0) 429 cp = ".rhosts lstat failed"; 430 else if (!S_ISREG(sbuf.st_mode)) 431 cp = ".rhosts not regular file"; 432 else if (fstat(fileno(hostf), &sbuf) < 0) 433 cp = ".rhosts fstat failed"; 434 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 435 cp = "bad .rhosts owner"; 436 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 437 cp = ".rhosts writeable by other than owner"; 438 /* If there were any problems, quit. */ 439 if (cp) { 440 __rcmd_errstr = cp; 441 (void)fclose(hostf); 442 return (-1); 443 } 444 goto again; 445 } 446 return (-1); 447 } 448 449 /* 450 * XXX 451 * Don't make static, used by lpd(8). 452 * 453 * Returns 0 if ok, -1 if not ok. 454 */ 455 int 456 __ivaliduser(hostf, raddrl, luser, ruser) 457 FILE *hostf; 458 in_addr_t raddrl; 459 const char *luser, *ruser; 460 { 461 struct sockaddr_in sin; 462 463 memset(&sin, 0, sizeof(sin)); 464 sin.sin_family = AF_INET; 465 sin.sin_len = sizeof(struct sockaddr_in); 466 memcpy(&sin.sin_addr, &raddrl, sizeof(sin.sin_addr)); 467 return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len, 468 luser, ruser); 469 } 470 471 int 472 __ivaliduser_sa(hostf, raddr, salen, luser, ruser) 473 FILE *hostf; 474 struct sockaddr *raddr; 475 socklen_t salen; 476 const char *luser, *ruser; 477 { 478 register char *user, *p; 479 char *buf; 480 const char *auser, *ahost; 481 int hostok, userok; 482 char *rhost = (char *)-1; 483 char domain[MAXHOSTNAMELEN]; 484 size_t buflen; 485 486 getdomainname(domain, sizeof(domain)); 487 488 while ((buf = fgetln(hostf, &buflen))) { 489 p = buf; 490 if (*p == '#') 491 continue; 492 while (*p != '\n' && *p != ' ' && *p != '\t' && p < buf + buflen) { 493 if (!isprint(*p)) 494 goto bail; 495 *p = isupper(*p) ? tolower(*p) : *p; 496 p++; 497 } 498 if (p >= buf + buflen) 499 continue; 500 if (*p == ' ' || *p == '\t') { 501 *p++ = '\0'; 502 while ((*p == ' ' || *p == '\t') && p < buf + buflen) 503 p++; 504 if (p >= buf + buflen) 505 continue; 506 user = p; 507 while (*p != '\n' && *p != ' ' && 508 *p != '\t' && p < buf + buflen) { 509 if (!isprint(*p)) 510 goto bail; 511 p++; 512 } 513 } else 514 user = p; 515 *p = '\0'; 516 517 if (p == buf) 518 continue; 519 520 auser = *user ? user : luser; 521 ahost = buf; 522 523 if (strlen(ahost) >= MAXHOSTNAMELEN) 524 continue; 525 526 /* 527 * innetgr() must lookup a hostname (we do not attempt 528 * to change the semantics so that netgroups may have 529 * #.#.#.# addresses in the list.) 530 */ 531 if (ahost[0] == '+') 532 switch (ahost[1]) { 533 case '\0': 534 hostok = 1; 535 break; 536 case '@': 537 if (rhost == (char *)-1) 538 rhost = __gethostloop(raddr, salen); 539 hostok = 0; 540 if (rhost) 541 hostok = innetgr(&ahost[2], rhost, 542 NULL, domain); 543 break; 544 default: 545 hostok = __icheckhost(raddr, salen, &ahost[1]); 546 break; 547 } 548 else if (ahost[0] == '-') 549 switch (ahost[1]) { 550 case '\0': 551 hostok = -1; 552 break; 553 case '@': 554 if (rhost == (char *)-1) 555 rhost = __gethostloop(raddr, salen); 556 hostok = 0; 557 if (rhost) 558 hostok = -innetgr(&ahost[2], rhost, 559 NULL, domain); 560 break; 561 default: 562 hostok = -__icheckhost(raddr, salen, &ahost[1]); 563 break; 564 } 565 else 566 hostok = __icheckhost(raddr, salen, ahost); 567 568 569 if (auser[0] == '+') 570 switch (auser[1]) { 571 case '\0': 572 userok = 1; 573 break; 574 case '@': 575 userok = innetgr(&auser[2], NULL, ruser, 576 domain); 577 break; 578 default: 579 userok = strcmp(ruser, &auser[1]) ? 0 : 1; 580 break; 581 } 582 else if (auser[0] == '-') 583 switch (auser[1]) { 584 case '\0': 585 userok = -1; 586 break; 587 case '@': 588 userok = -innetgr(&auser[2], NULL, ruser, 589 domain); 590 break; 591 default: 592 userok = strcmp(ruser, &auser[1]) ? 0 : -1; 593 break; 594 } 595 else 596 userok = strcmp(ruser, auser) ? 0 : 1; 597 598 /* Check if one component did not match */ 599 if (hostok == 0 || userok == 0) 600 continue; 601 602 /* Check if we got a forbidden pair */ 603 if (userok <= -1 || hostok <= -1) 604 return (-1); 605 606 /* Check if we got a valid pair */ 607 if (hostok >= 1 && userok >= 1) 608 return (0); 609 } 610 bail: 611 return (-1); 612 } 613 614 /* 615 * Returns "true" if match, 0 if no match. If we do not find any 616 * semblance of an A->PTR->A loop, allow a simple #.#.#.# match to work. 617 * 618 * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion 619 * if af == AF_INET6. 620 */ 621 static int 622 __icheckhost(raddr, salen, lhost) 623 struct sockaddr *raddr; 624 socklen_t salen; 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, salen, 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, salen) 679 struct sockaddr *raddr; 680 socklen_t salen; 681 { 682 static char remotehost[NI_MAXHOST]; 683 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 684 struct addrinfo hints, *res, *r; 685 int error; 686 #ifdef NI_WITHSCOPEID 687 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID; 688 #else 689 const int niflags = NI_NUMERICHOST; 690 #endif 691 692 h1[0] = remotehost[0] = '\0'; 693 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost), 694 NULL, 0, NI_NAMEREQD) != 0) 695 return (NULL); 696 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, 697 niflags) != 0) 698 return (NULL); 699 700 /* 701 * Look up the name and check that the supplied 702 * address is in the list 703 */ 704 memset(&hints, 0, sizeof(hints)); 705 hints.ai_family = raddr->sa_family; 706 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 707 hints.ai_flags = AI_CANONNAME; 708 res = NULL; 709 error = getaddrinfo(remotehost, "0", &hints, &res); 710 if (error) 711 return (NULL); 712 713 for (r = res; r; r = r->ai_next) { 714 h2[0] = '\0'; 715 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 716 NULL, 0, niflags) != 0) 717 continue; 718 if (strcmp(h1, h2) == 0) { 719 freeaddrinfo(res); 720 return (remotehost); 721 } 722 } 723 724 /* 725 * either the DNS adminstrator has made a configuration 726 * mistake, or someone has attempted to spoof us 727 */ 728 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 729 h1, res->ai_canonname ? res->ai_canonname : remotehost); 730 freeaddrinfo(res); 731 return (NULL); 732 } 733