1 /* $NetBSD: rcmd.c,v 1.28 1998/11/13 15:46:56 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Matthew R. Green. 5 * Copyright (c) 1983, 1993, 1994 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 #if defined(LIBC_SCCS) && !defined(lint) 39 #if 0 40 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 41 #else 42 __RCSID("$NetBSD: rcmd.c,v 1.28 1998/11/13 15:46:56 christos Exp $"); 43 #endif 44 #endif /* LIBC_SCCS and not lint */ 45 46 #include "namespace.h" 47 #include <sys/param.h> 48 #include <sys/socket.h> 49 #include <sys/stat.h> 50 #include <sys/poll.h> 51 #include <sys/wait.h> 52 53 #include <netinet/in.h> 54 #include <rpc/rpc.h> 55 #include <arpa/inet.h> 56 #include <netgroup.h> 57 58 #include <signal.h> 59 #include <fcntl.h> 60 #include <netdb.h> 61 #include <unistd.h> 62 #include <pwd.h> 63 #include <errno.h> 64 #include <stdio.h> 65 #include <ctype.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <stdlib.h> 69 #include <paths.h> 70 #include <err.h> 71 72 #include "pathnames.h" 73 74 int orcmd __P((char **, u_int, const char *, const char *, const char *, 75 int *)); 76 int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *)); 77 static int rshrcmd __P((char **, u_int32_t, const char *, const char *, 78 const char *, int *, const char *)); 79 static int hprcmd __P((struct hostent *, char **, u_int32_t, const char *, 80 const char *, const char *, int *)); 81 static int __icheckhost __P((u_int32_t, const char *)); 82 static char *__gethostloop __P((u_int32_t)); 83 84 int 85 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 86 char **ahost; 87 u_short rport; 88 const char *locuser, *remuser, *cmd; 89 int *fd2p; 90 { 91 struct hostent *hp; 92 struct servent *sp; 93 94 /* 95 * Canonicalise hostname. 96 * XXX: Should we really do this? 97 */ 98 hp = gethostbyname(*ahost); 99 if (hp == NULL) { 100 herror(*ahost); 101 return (-1); 102 } 103 *ahost = hp->h_name; 104 105 /* 106 * Check if rport is the same as the shell port, and that the fd2p. If 107 * it is not, the program isn't expecting 'rsh' and so we can't use the 108 * RCMD_CMD environment. 109 */ 110 sp = getservbyname("shell", "tcp"); 111 if (sp != NULL && sp->s_port == rport) 112 return (rshrcmd(ahost, rport, locuser, remuser, cmd, fd2p, 113 getenv("RCMD_CMD"))); 114 else 115 return (hprcmd(hp, ahost, rport, locuser, remuser, cmd, fd2p)); 116 } 117 118 /* this is simply a wrapper around hprcmd() that handles ahost first */ 119 int 120 orcmd(ahost, rport, locuser, remuser, cmd, fd2p) 121 char **ahost; 122 u_int rport; 123 const char *locuser, *remuser, *cmd; 124 int *fd2p; 125 { 126 struct hostent *hp; 127 128 hp = gethostbyname(*ahost); 129 if (hp == NULL) { 130 herror(*ahost); 131 return (-1); 132 } 133 *ahost = hp->h_name; 134 135 return (hprcmd(hp, ahost, rport, locuser, remuser, cmd, fd2p)); 136 } 137 138 static int 139 hprcmd(hp, ahost, rport, locuser, remuser, cmd, fd2p) 140 struct hostent *hp; 141 char **ahost; 142 u_int32_t rport; 143 const char *locuser, *remuser, *cmd; 144 int *fd2p; 145 { 146 struct sockaddr_in sin, from; 147 struct pollfd reads[2]; 148 sigset_t nmask, omask; 149 pid_t pid; 150 int s, lport, timo; 151 int pollr; 152 char c; 153 154 pid = getpid(); 155 sigemptyset(&nmask); 156 sigaddset(&nmask, SIGURG); 157 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) 158 return -1; 159 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 160 s = rresvport(&lport); 161 if (s < 0) { 162 if (errno == EAGAIN) 163 warnx("rcmd: socket: All ports in use"); 164 else 165 warn("rcmd: socket"); 166 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 167 return (-1); 168 } 169 fcntl(s, F_SETOWN, pid); 170 #ifdef BSD4_4 171 sin.sin_len = sizeof(struct sockaddr_in); 172 #endif 173 sin.sin_family = hp->h_addrtype; 174 sin.sin_port = rport; 175 memmove(&sin.sin_addr, 176 hp->h_addr_list[0], (size_t)hp->h_length); 177 if (connect(s, (struct sockaddr *)(void *)&sin, sizeof(sin)) >= 0) 178 break; 179 (void)close(s); 180 if (errno == EADDRINUSE) { 181 lport--; 182 continue; 183 } 184 if (errno == ECONNREFUSED && timo <= 16) { 185 (void)sleep((unsigned int)timo); 186 timo *= 2; 187 continue; 188 } 189 if (hp->h_addr_list[1] != NULL) { 190 int oerrno = errno; 191 192 warnx("rcmd: connect to address %s", 193 inet_ntoa(sin.sin_addr)); 194 errno = oerrno; 195 perror(0); 196 hp->h_addr_list++; 197 memmove(&sin.sin_addr, hp->h_addr_list[0], 198 (size_t)hp->h_length); 199 (void)fprintf(stderr, "Trying %s...\n", 200 inet_ntoa(sin.sin_addr)); 201 continue; 202 } 203 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno)); 204 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 205 return (-1); 206 } 207 lport--; 208 if (fd2p == 0) { 209 write(s, "", 1); 210 lport = 0; 211 } else { 212 char num[8]; 213 int s2 = rresvport(&lport), s3; 214 int len = sizeof(from); 215 216 if (s2 < 0) 217 goto bad; 218 listen(s2, 1); 219 (void)snprintf(num, sizeof(num), "%d", lport); 220 if (write(s, num, strlen(num) + 1) != strlen(num) + 1) { 221 warn("rcmd: write (setting up stderr)"); 222 (void)close(s2); 223 goto bad; 224 } 225 reads[0].fd = s; 226 reads[0].events = POLLIN; 227 reads[1].fd = s2; 228 reads[1].events = POLLIN; 229 errno = 0; 230 pollr = poll(reads, 2, INFTIM); 231 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 232 if (errno != 0) 233 warn("poll: setting up stderr"); 234 else 235 warnx("poll: protocol failure in circuit setup"); 236 (void)close(s2); 237 goto bad; 238 } 239 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 240 (void)close(s2); 241 if (s3 < 0) { 242 warn("rcmd: accept"); 243 lport = 0; 244 goto bad; 245 } 246 *fd2p = s3; 247 from.sin_port = ntohs(from.sin_port); 248 if (from.sin_family != AF_INET || 249 from.sin_port >= IPPORT_RESERVED || 250 from.sin_port < IPPORT_RESERVED / 2) { 251 warnx("rcmd: protocol failure in circuit setup."); 252 goto bad2; 253 } 254 } 255 256 (void)write(s, locuser, strlen(locuser)+1); 257 (void)write(s, remuser, strlen(remuser)+1); 258 (void)write(s, cmd, strlen(cmd)+1); 259 if (read(s, &c, 1) != 1) { 260 warn("%s", *ahost); 261 goto bad2; 262 } 263 if (c != 0) { 264 while (read(s, &c, 1) == 1) { 265 (void)write(STDERR_FILENO, &c, 1); 266 if (c == '\n') 267 break; 268 } 269 goto bad2; 270 } 271 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 272 return (s); 273 bad2: 274 if (lport) 275 (void)close(*fd2p); 276 bad: 277 (void)close(s); 278 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 279 return (-1); 280 } 281 282 /* 283 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 284 */ 285 /* ARGSUSED */ 286 static int 287 rshrcmd(ahost, rport, locuser, remuser, cmd, fd2p, rshcmd) 288 char **ahost; 289 u_int32_t rport; 290 const char *locuser, *remuser, *cmd; 291 int *fd2p; 292 const char *rshcmd; 293 { 294 pid_t pid; 295 int sp[2], ep[2]; 296 char *p; 297 struct passwd *pw; 298 299 /* What rsh/shell to use. */ 300 if (rshcmd == NULL) 301 rshcmd = _PATH_BIN_RCMD; 302 303 /* locuser must exist on this host. */ 304 if ((pw = getpwnam(locuser)) == NULL) { 305 warnx("rshrcmd: unknown user: %s", locuser); 306 return(-1); 307 } 308 309 /* get a socketpair we'll use for stdin and stdout. */ 310 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 311 warn("rshrcmd: socketpair"); 312 return (-1); 313 } 314 /* we will use this for the fd2 pointer */ 315 if (fd2p) { 316 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 317 warn("rshrcmd: socketpair"); 318 return (-1); 319 } 320 *fd2p = ep[0]; 321 } 322 323 pid = fork(); 324 if (pid < 0) { 325 warn("rshrcmd: fork"); 326 return (-1); 327 } 328 if (pid == 0) { 329 /* 330 * child 331 * - we use sp[1] to be stdin/stdout, and close sp[0] 332 * - with fd2p, we use ep[1] for stderr, and close ep[0] 333 */ 334 (void)close(sp[0]); 335 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 336 warn("rshrcmd: dup2"); 337 _exit(1); 338 } 339 if (fd2p) { 340 if (dup2(ep[1], 2) < 0) { 341 warn("rshrcmd: dup2"); 342 _exit(1); 343 } 344 (void)close(ep[0]); 345 (void)close(ep[1]); 346 } else if (dup2(0, 2) < 0) { 347 warn("rshrcmd: dup2"); 348 _exit(1); 349 } 350 /* fork again to lose parent. */ 351 pid = fork(); 352 if (pid < 0) { 353 warn("rshrcmd: second fork"); 354 _exit(1); 355 } 356 if (pid > 0) 357 _exit(0); 358 359 /* Orphan. Become local user for rshprog. */ 360 if (setuid(pw->pw_uid)) { 361 warn("rshrcmd: setuid(%u)", pw->pw_uid); 362 _exit(1); 363 } 364 365 /* 366 * If we are rcmd'ing to "localhost" as the same user as we are, 367 * then avoid running remote shell for efficiency. 368 */ 369 if (strcmp(*ahost, "localhost") == 0 && 370 strcmp(locuser, remuser) == 0) { 371 if (pw->pw_shell[0] == '\0') 372 rshcmd = _PATH_BSHELL; 373 else 374 rshcmd = pw->pw_shell; 375 p = strrchr(rshcmd, '/'); 376 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 377 } else { 378 p = strrchr(rshcmd, '/'); 379 execlp(rshcmd, p ? p + 1 : rshcmd, *ahost, "-l", 380 remuser, cmd, NULL); 381 } 382 warn("rshrcmd: exec %s", rshcmd); 383 _exit(1); 384 } 385 /* Parent */ 386 (void)close(sp[1]); 387 if (fd2p) 388 (void)close(ep[1]); 389 390 (void)waitpid(pid, NULL, 0); 391 return (sp[0]); 392 } 393 394 int 395 rresvport(alport) 396 int *alport; 397 { 398 struct sockaddr_in sin; 399 int s; 400 401 #ifdef BSD4_4 402 sin.sin_len = sizeof(struct sockaddr_in); 403 #endif 404 sin.sin_family = AF_INET; 405 sin.sin_addr.s_addr = INADDR_ANY; 406 s = socket(AF_INET, SOCK_STREAM, 0); 407 if (s < 0) 408 return (-1); 409 #if 0 410 for (;;) { 411 sin.sin_port = htons((u_short)*alport); 412 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 413 return (s); 414 if (errno != EADDRINUSE) { 415 (void)close(s); 416 return (-1); 417 } 418 (*alport)--; 419 if (*alport == IPPORT_RESERVED/2) { 420 (void)close(s); 421 errno = EAGAIN; /* close */ 422 return (-1); 423 } 424 } 425 #else 426 sin.sin_port = 0; 427 if (bindresvport(s, &sin) < 0) { 428 int sverr = errno; 429 430 (void)close(s); 431 errno = sverr; 432 return (-1); 433 } 434 *alport = (int)ntohs(sin.sin_port); 435 return (s); 436 #endif 437 } 438 439 int __check_rhosts_file = 1; 440 char *__rcmd_errstr; 441 442 int 443 ruserok(rhost, superuser, ruser, luser) 444 const char *rhost, *ruser, *luser; 445 int superuser; 446 { 447 struct hostent *hp; 448 char **ap; 449 int i; 450 #define MAXADDRS 35 451 u_int32_t addrs[MAXADDRS + 1]; 452 453 if ((hp = gethostbyname(rhost)) == NULL) 454 return (-1); 455 for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i) 456 memmove(&addrs[i], *ap, sizeof(addrs[i])); 457 addrs[i] = 0; 458 459 for (i = 0; i < MAXADDRS && addrs[i]; i++) 460 if (iruserok(addrs[i], superuser, ruser, luser) == 0) 461 return (0); 462 return (-1); 463 } 464 465 /* 466 * New .rhosts strategy: We are passed an ip address. We spin through 467 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 468 * has ip addresses, we don't have to trust a nameserver. When it 469 * contains hostnames, we spin through the list of addresses the nameserver 470 * gives us and look for a match. 471 * 472 * Returns 0 if ok, -1 if not ok. 473 */ 474 int 475 iruserok(raddr, superuser, ruser, luser) 476 u_int32_t raddr; 477 int superuser; 478 const char *ruser, *luser; 479 { 480 register char *cp; 481 struct stat sbuf; 482 struct passwd *pwd; 483 FILE *hostf; 484 uid_t uid; 485 gid_t gid; 486 int first; 487 char pbuf[MAXPATHLEN]; 488 489 first = 1; 490 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 491 again: 492 if (hostf) { 493 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) { 494 (void)fclose(hostf); 495 return (0); 496 } 497 (void)fclose(hostf); 498 } 499 if (first == 1 && (__check_rhosts_file || superuser)) { 500 first = 0; 501 if ((pwd = getpwnam(luser)) == NULL) 502 return (-1); 503 (void)strncpy(pbuf, pwd->pw_dir, sizeof(pbuf) - 1); 504 (void)strncat(pbuf, "/.rhosts", sizeof(pbuf) - strlen(pbuf) - 1); 505 506 /* 507 * Change effective uid while opening .rhosts. If root and 508 * reading an NFS mounted file system, can't read files that 509 * are protected read/write owner only. 510 */ 511 uid = geteuid(); 512 gid = getegid(); 513 (void)setegid(pwd->pw_gid); 514 initgroups(pwd->pw_name, pwd->pw_gid); 515 (void)seteuid(pwd->pw_uid); 516 hostf = fopen(pbuf, "r"); 517 (void)seteuid(uid); 518 (void)setegid(gid); 519 520 if (hostf == NULL) 521 return (-1); 522 /* 523 * If not a regular file, or is owned by someone other than 524 * user or root or if writeable by anyone but the owner, quit. 525 */ 526 cp = NULL; 527 if (lstat(pbuf, &sbuf) < 0) 528 cp = ".rhosts lstat failed"; 529 else if (!S_ISREG(sbuf.st_mode)) 530 cp = ".rhosts not regular file"; 531 else if (fstat(fileno(hostf), &sbuf) < 0) 532 cp = ".rhosts fstat failed"; 533 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 534 cp = "bad .rhosts owner"; 535 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 536 cp = ".rhosts writeable by other than owner"; 537 /* If there were any problems, quit. */ 538 if (cp) { 539 __rcmd_errstr = cp; 540 (void)fclose(hostf); 541 return (-1); 542 } 543 goto again; 544 } 545 return (-1); 546 } 547 548 /* 549 * XXX 550 * Don't make static, used by lpd(8). 551 * 552 * Returns 0 if ok, -1 if not ok. 553 */ 554 int 555 __ivaliduser(hostf, raddr, luser, ruser) 556 FILE *hostf; 557 u_int32_t raddr; 558 const char *luser, *ruser; 559 { 560 register char *user, *p; 561 int ch; 562 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 563 const char *auser, *ahost; 564 int hostok, userok; 565 char *rhost = NULL; 566 int firsttime = 1; 567 char domain[MAXHOSTNAMELEN]; 568 569 getdomainname(domain, sizeof(domain)); 570 571 while (fgets(buf, sizeof(buf), hostf)) { 572 p = buf; 573 /* Skip lines that are too long. */ 574 if (strchr(p, '\n') == NULL) { 575 while ((ch = getc(hostf)) != '\n' && ch != EOF) 576 ; 577 continue; 578 } 579 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 580 *p = isupper(*p) ? tolower(*p) : *p; 581 p++; 582 } 583 if (*p == ' ' || *p == '\t') { 584 *p++ = '\0'; 585 while (*p == ' ' || *p == '\t') 586 p++; 587 user = p; 588 while (*p != '\n' && *p != ' ' && 589 *p != '\t' && *p != '\0') 590 p++; 591 } else 592 user = p; 593 *p = '\0'; 594 595 if (p == buf) 596 continue; 597 598 auser = *user ? user : luser; 599 ahost = buf; 600 601 if (ahost[0] == '+') 602 switch (ahost[1]) { 603 case '\0': 604 hostok = 1; 605 break; 606 607 case '@': 608 if (firsttime) { 609 rhost = __gethostloop(raddr); 610 firsttime = 0; 611 } 612 if (rhost) 613 hostok = innetgr(&ahost[2], rhost, 614 NULL, domain); 615 else 616 hostok = 0; 617 break; 618 619 default: 620 hostok = __icheckhost(raddr, &ahost[1]); 621 break; 622 } 623 else if (ahost[0] == '-') 624 switch (ahost[1]) { 625 case '\0': 626 hostok = -1; 627 break; 628 629 case '@': 630 if (firsttime) { 631 rhost = __gethostloop(raddr); 632 firsttime = 0; 633 } 634 if (rhost) 635 hostok = -innetgr(&ahost[2], rhost, 636 NULL, domain); 637 else 638 hostok = 0; 639 break; 640 641 default: 642 hostok = -__icheckhost(raddr, &ahost[1]); 643 break; 644 } 645 else 646 hostok = __icheckhost(raddr, ahost); 647 648 649 if (auser[0] == '+') 650 switch (auser[1]) { 651 case '\0': 652 userok = 1; 653 break; 654 655 case '@': 656 userok = innetgr(&auser[2], NULL, ruser, 657 domain); 658 break; 659 660 default: 661 userok = strcmp(ruser, &auser[1]) == 0; 662 break; 663 } 664 else if (auser[0] == '-') 665 switch (auser[1]) { 666 case '\0': 667 userok = -1; 668 break; 669 670 case '@': 671 userok = -innetgr(&auser[2], NULL, ruser, 672 domain); 673 break; 674 675 default: 676 userok = 677 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 678 break; 679 } 680 else 681 userok = strcmp(ruser, auser) == 0; 682 683 /* Check if one component did not match */ 684 if (hostok == 0 || userok == 0) 685 continue; 686 687 /* Check if we got a forbidden pair */ 688 if (userok == -1 || hostok == -1) 689 return -1; 690 691 /* Check if we got a valid pair */ 692 if (hostok == 1 && userok == 1) 693 return 0; 694 } 695 return -1; 696 } 697 698 /* 699 * Returns "true" if match, 0 if no match. 700 */ 701 static int 702 __icheckhost(raddr, lhost) 703 u_int32_t raddr; 704 const char *lhost; 705 { 706 struct hostent *hp; 707 struct in_addr laddr; 708 char **pp; 709 710 /* Try for raw ip address first. */ 711 if (isdigit(*lhost) && inet_aton(lhost, &laddr) != 0) 712 return (raddr == laddr.s_addr); 713 714 /* Better be a hostname. */ 715 if ((hp = gethostbyname(lhost)) == NULL) 716 return (0); 717 718 /* Spin through ip addresses. */ 719 for (pp = hp->h_addr_list; *pp; ++pp) 720 if (!memcmp(&raddr, *pp, sizeof(u_int32_t))) 721 return (1); 722 723 /* No match. */ 724 return (0); 725 } 726 727 /* 728 * Return the hostname associated with the supplied address. 729 * Do a reverse lookup as well for security. If a loop cannot 730 * be found, pack the result of inet_ntoa() into the string. 731 */ 732 static char * 733 __gethostloop(raddr) 734 u_int32_t raddr; 735 { 736 static char remotehost[MAXHOSTNAMELEN]; 737 struct hostent *hp; 738 struct in_addr in; 739 740 hp = gethostbyaddr((char *)(void *)&raddr, sizeof(raddr), AF_INET); 741 if (hp == NULL) 742 return (NULL); 743 744 /* 745 * Look up the name and check that the supplied 746 * address is in the list 747 */ 748 strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1); 749 remotehost[sizeof(remotehost) - 1] = '\0'; 750 hp = gethostbyname(remotehost); 751 if (hp == NULL) 752 return (NULL); 753 754 for (; hp->h_addr_list[0] != NULL; hp->h_addr_list++) 755 if (!memcmp(hp->h_addr_list[0], &raddr, sizeof(raddr))) 756 return (remotehost); 757 758 /* 759 * either the DNS adminstrator has made a configuration 760 * mistake, or someone has attempted to spoof us 761 */ 762 in.s_addr = raddr; 763 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 764 inet_ntoa(in), hp->h_name); 765 return (NULL); 766 } 767