1 /* $NetBSD: rcmd.c,v 1.64 2006/11/03 20:21:16 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 36 #else 37 __RCSID("$NetBSD: rcmd.c,v 1.64 2006/11/03 20:21:16 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #ifdef _LIBC 42 #include "namespace.h" 43 #endif 44 #include <sys/param.h> 45 #include <sys/socket.h> 46 #include <sys/stat.h> 47 #include <sys/poll.h> 48 #include <sys/wait.h> 49 50 #include <netinet/in.h> 51 #include <rpc/rpc.h> 52 #include <arpa/inet.h> 53 #include <netgroup.h> 54 55 #include <assert.h> 56 #include <ctype.h> 57 #include <err.h> 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <grp.h> 61 #include <netdb.h> 62 #include <paths.h> 63 #include <pwd.h> 64 #include <signal.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <syslog.h> 69 #include <unistd.h> 70 71 #include "pathnames.h" 72 73 int orcmd __P((char **, u_int, const char *, const char *, const char *, 74 int *)); 75 int orcmd_af __P((char **, u_int, const char *, const char *, const char *, 76 int *, int)); 77 int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *)); 78 int __ivaliduser_sa __P((FILE *, const struct sockaddr *, socklen_t, 79 const char *, const char *)); 80 static int rshrcmd __P((char **, u_int32_t, const char *, const char *, 81 const char *, int *, const char *)); 82 static int resrcmd __P((struct addrinfo *, char **, u_int32_t, const char *, 83 const char *, const char *, int *)); 84 static int __icheckhost __P((const struct sockaddr *, socklen_t, 85 const char *)); 86 static char *__gethostloop __P((const struct sockaddr *, socklen_t)); 87 88 int 89 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 90 char **ahost; 91 u_short rport; 92 const char *locuser, *remuser, *cmd; 93 int *fd2p; 94 { 95 96 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 97 } 98 99 int 100 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 101 char **ahost; 102 u_short rport; 103 const char *locuser, *remuser, *cmd; 104 int *fd2p; 105 int af; 106 { 107 static char hbuf[MAXHOSTNAMELEN]; 108 char pbuf[NI_MAXSERV]; 109 struct addrinfo hints, *res; 110 int error; 111 struct servent *sp; 112 113 _DIAGASSERT(ahost != NULL); 114 _DIAGASSERT(locuser != NULL); 115 _DIAGASSERT(remuser != NULL); 116 _DIAGASSERT(cmd != NULL); 117 /* fd2p may be NULL */ 118 119 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 120 memset(&hints, 0, sizeof(hints)); 121 hints.ai_family = af; 122 hints.ai_socktype = SOCK_STREAM; 123 hints.ai_flags = AI_CANONNAME; 124 error = getaddrinfo(*ahost, pbuf, &hints, &res); 125 if (error) { 126 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 127 return (-1); 128 } 129 if (res->ai_canonname) { 130 /* 131 * Canonicalise hostname. 132 * XXX: Should we really do this? 133 */ 134 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 135 *ahost = hbuf; 136 } 137 138 /* 139 * Check if rport is the same as the shell port, and that the fd2p. If 140 * it is not, the program isn't expecting 'rsh' and so we can't use the 141 * RCMD_CMD environment. 142 */ 143 sp = getservbyname("shell", "tcp"); 144 if (sp != NULL && sp->s_port == rport) 145 error = rshrcmd(ahost, (u_int32_t)rport, 146 locuser, remuser, cmd, fd2p, getenv("RCMD_CMD")); 147 else 148 error = resrcmd(res, ahost, (u_int32_t)rport, 149 locuser, remuser, cmd, fd2p); 150 freeaddrinfo(res); 151 return (error); 152 } 153 154 /* this is simply a wrapper around hprcmd() that handles ahost first */ 155 int 156 orcmd(ahost, rport, locuser, remuser, cmd, fd2p) 157 char **ahost; 158 u_int rport; 159 const char *locuser, *remuser, *cmd; 160 int *fd2p; 161 { 162 return orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 163 } 164 165 int 166 orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af) 167 char **ahost; 168 u_int rport; 169 const char *locuser, *remuser, *cmd; 170 int *fd2p; 171 int af; 172 { 173 static char hbuf[MAXHOSTNAMELEN]; 174 char pbuf[NI_MAXSERV]; 175 struct addrinfo hints, *res; 176 int error; 177 178 _DIAGASSERT(ahost != NULL); 179 _DIAGASSERT(locuser != NULL); 180 _DIAGASSERT(remuser != NULL); 181 _DIAGASSERT(cmd != NULL); 182 /* fd2p may be NULL */ 183 184 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 185 memset(&hints, 0, sizeof(hints)); 186 hints.ai_family = af; 187 hints.ai_socktype = SOCK_STREAM; 188 hints.ai_flags = AI_CANONNAME; 189 error = getaddrinfo(*ahost, pbuf, &hints, &res); 190 if (error) { 191 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 192 return (-1); 193 } 194 if (res->ai_canonname) { 195 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 196 *ahost = hbuf; 197 } 198 199 error = resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p); 200 freeaddrinfo(res); 201 return (error); 202 } 203 204 /*ARGSUSED*/ 205 static int 206 resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p) 207 struct addrinfo *res; 208 char **ahost; 209 u_int32_t rport; 210 const char *locuser, *remuser, *cmd; 211 int *fd2p; 212 { 213 struct addrinfo *r; 214 struct sockaddr_storage from; 215 struct pollfd reads[2]; 216 sigset_t nmask, omask; 217 pid_t pid; 218 int s, lport, timo; 219 int pollr; 220 char c; 221 int refused; 222 223 _DIAGASSERT(res != NULL); 224 _DIAGASSERT(ahost != NULL); 225 _DIAGASSERT(locuser != NULL); 226 _DIAGASSERT(remuser != NULL); 227 _DIAGASSERT(cmd != NULL); 228 /* fd2p may be NULL */ 229 230 r = res; 231 refused = 0; 232 pid = getpid(); 233 sigemptyset(&nmask); 234 sigaddset(&nmask, SIGURG); 235 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) 236 return -1; 237 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 238 s = rresvport_af(&lport, r->ai_family); 239 if (s < 0) { 240 if (errno == EAGAIN) 241 warnx("rcmd: socket: All ports in use"); 242 else 243 warn("rcmd: socket"); 244 if (r->ai_next) { 245 r = r->ai_next; 246 continue; 247 } else { 248 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 249 return (-1); 250 } 251 } 252 fcntl(s, F_SETOWN, pid); 253 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 254 break; 255 (void)close(s); 256 if (errno == EADDRINUSE) { 257 lport--; 258 continue; 259 } else if (errno == ECONNREFUSED) 260 refused++; 261 if (r->ai_next) { 262 int oerrno = errno; 263 char hbuf[NI_MAXHOST]; 264 const int niflags = NI_NUMERICHOST; 265 266 hbuf[0] = '\0'; 267 if (getnameinfo(r->ai_addr, r->ai_addrlen, 268 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 269 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 270 errno = oerrno; 271 warn("rcmd: connect to address %s", hbuf); 272 r = r->ai_next; 273 hbuf[0] = '\0'; 274 if (getnameinfo(r->ai_addr, r->ai_addrlen, 275 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 276 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 277 (void)fprintf(stderr, "Trying %s...\n", hbuf); 278 continue; 279 } 280 if (refused && timo <= 16) { 281 (void)sleep((unsigned int)timo); 282 timo *= 2; 283 r = res; 284 refused = 0; 285 continue; 286 } 287 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 288 strerror(errno)); 289 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 290 return (-1); 291 } 292 lport--; 293 if (fd2p == 0) { 294 write(s, "", 1); 295 lport = 0; 296 } else { 297 char num[8]; 298 int s2 = rresvport_af(&lport, r->ai_family), s3; 299 socklen_t len = sizeof(from); 300 301 if (s2 < 0) 302 goto bad; 303 listen(s2, 1); 304 (void)snprintf(num, sizeof(num), "%d", lport); 305 if (write(s, num, strlen(num) + 1) != 306 (ssize_t) (strlen(num) + 1)) { 307 warn("rcmd: write (setting up stderr)"); 308 (void)close(s2); 309 goto bad; 310 } 311 reads[0].fd = s; 312 reads[0].events = POLLIN; 313 reads[1].fd = s2; 314 reads[1].events = POLLIN; 315 errno = 0; 316 pollr = poll(reads, 2, INFTIM); 317 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 318 if (errno != 0) 319 warn("poll: setting up stderr"); 320 else 321 warnx("poll: protocol failure in circuit setup"); 322 (void)close(s2); 323 goto bad; 324 } 325 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 326 (void)close(s2); 327 if (s3 < 0) { 328 warn("rcmd: accept"); 329 lport = 0; 330 goto bad; 331 } 332 *fd2p = s3; 333 switch (((struct sockaddr *)(void *)&from)->sa_family) { 334 case AF_INET: 335 #ifdef INET6 336 case AF_INET6: 337 #endif 338 if (getnameinfo((struct sockaddr *)(void *)&from, len, 339 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 || 340 (atoi(num) >= IPPORT_RESERVED || 341 atoi(num) < IPPORT_RESERVED / 2)) { 342 warnx("rcmd: protocol failure in circuit setup."); 343 goto bad2; 344 } 345 break; 346 default: 347 break; 348 } 349 } 350 351 (void)write(s, locuser, strlen(locuser)+1); 352 (void)write(s, remuser, strlen(remuser)+1); 353 (void)write(s, cmd, strlen(cmd)+1); 354 if (read(s, &c, 1) != 1) { 355 warn("%s", *ahost); 356 goto bad2; 357 } 358 if (c != 0) { 359 while (read(s, &c, 1) == 1) { 360 (void)write(STDERR_FILENO, &c, 1); 361 if (c == '\n') 362 break; 363 } 364 goto bad2; 365 } 366 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 367 return (s); 368 bad2: 369 if (lport) 370 (void)close(*fd2p); 371 bad: 372 (void)close(s); 373 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 374 return (-1); 375 } 376 377 /* 378 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 379 */ 380 /* ARGSUSED */ 381 static int 382 rshrcmd(ahost, rport, locuser, remuser, cmd, fd2p, rshcmd) 383 char **ahost; 384 u_int32_t rport; 385 const char *locuser, *remuser, *cmd; 386 int *fd2p; 387 const char *rshcmd; 388 { 389 pid_t pid; 390 int sp[2], ep[2]; 391 char *p; 392 struct passwd *pw, pwres; 393 char pwbuf[1024]; 394 395 _DIAGASSERT(ahost != NULL); 396 _DIAGASSERT(locuser != NULL); 397 _DIAGASSERT(remuser != NULL); 398 _DIAGASSERT(cmd != NULL); 399 /* fd2p may be NULL */ 400 401 /* What rsh/shell to use. */ 402 if (rshcmd == NULL) 403 rshcmd = _PATH_BIN_RCMD; 404 405 /* locuser must exist on this host. */ 406 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || 407 pw == NULL) { 408 warnx("rshrcmd: unknown user: %s", locuser); 409 return(-1); 410 } 411 412 /* get a socketpair we'll use for stdin and stdout. */ 413 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 414 warn("rshrcmd: socketpair"); 415 return (-1); 416 } 417 /* we will use this for the fd2 pointer */ 418 if (fd2p) { 419 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 420 warn("rshrcmd: socketpair"); 421 return (-1); 422 } 423 *fd2p = ep[0]; 424 } 425 426 pid = fork(); 427 if (pid < 0) { 428 warn("rshrcmd: fork"); 429 return (-1); 430 } 431 if (pid == 0) { 432 /* 433 * child 434 * - we use sp[1] to be stdin/stdout, and close sp[0] 435 * - with fd2p, we use ep[1] for stderr, and close ep[0] 436 */ 437 (void)close(sp[0]); 438 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 439 warn("rshrcmd: dup2"); 440 _exit(1); 441 } 442 if (fd2p) { 443 if (dup2(ep[1], 2) < 0) { 444 warn("rshrcmd: dup2"); 445 _exit(1); 446 } 447 (void)close(ep[0]); 448 (void)close(ep[1]); 449 } else if (dup2(0, 2) < 0) { 450 warn("rshrcmd: dup2"); 451 _exit(1); 452 } 453 /* fork again to lose parent. */ 454 pid = fork(); 455 if (pid < 0) { 456 warn("rshrcmd: second fork"); 457 _exit(1); 458 } 459 if (pid > 0) 460 _exit(0); 461 462 /* Orphan. Become local user for rshprog. */ 463 if (setuid(pw->pw_uid)) { 464 warn("rshrcmd: setuid(%lu)", (u_long)pw->pw_uid); 465 _exit(1); 466 } 467 468 /* 469 * If we are rcmd'ing to "localhost" as the same user as we are, 470 * then avoid running remote shell for efficiency. 471 */ 472 if (strcmp(*ahost, "localhost") == 0 && 473 strcmp(locuser, remuser) == 0) { 474 if (pw->pw_shell[0] == '\0') 475 rshcmd = _PATH_BSHELL; 476 else 477 rshcmd = pw->pw_shell; 478 p = strrchr(rshcmd, '/'); 479 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 480 } else { 481 p = strrchr(rshcmd, '/'); 482 execlp(rshcmd, p ? p + 1 : rshcmd, *ahost, "-l", 483 remuser, cmd, NULL); 484 } 485 warn("rshrcmd: exec %s", rshcmd); 486 _exit(1); 487 } 488 /* Parent */ 489 (void)close(sp[1]); 490 if (fd2p) 491 (void)close(ep[1]); 492 493 (void)waitpid(pid, NULL, 0); 494 return (sp[0]); 495 } 496 497 int 498 rresvport(alport) 499 int *alport; 500 { 501 502 _DIAGASSERT(alport != NULL); 503 504 return rresvport_af(alport, AF_INET); 505 } 506 507 int 508 rresvport_af(alport, family) 509 int *alport; 510 int family; 511 { 512 struct sockaddr_storage ss; 513 struct sockaddr *sa; 514 int salen; 515 int s; 516 u_int16_t *portp; 517 518 _DIAGASSERT(alport != NULL); 519 520 memset(&ss, 0, sizeof(ss)); 521 sa = (struct sockaddr *)(void *)&ss; 522 switch (family) { 523 case AF_INET: 524 #ifdef BSD4_4 525 sa->sa_len = 526 #endif 527 salen = sizeof(struct sockaddr_in); 528 portp = &((struct sockaddr_in *)(void *)sa)->sin_port; 529 break; 530 #ifdef INET6 531 case AF_INET6: 532 #ifdef BSD4_4 533 sa->sa_len = 534 #endif 535 salen = sizeof(struct sockaddr_in6); 536 portp = &((struct sockaddr_in6 *)(void *)sa)->sin6_port; 537 break; 538 #endif 539 default: 540 errno = EAFNOSUPPORT; 541 return (-1); 542 } 543 sa->sa_family = family; 544 s = socket(family, SOCK_STREAM, 0); 545 if (s < 0) 546 return (-1); 547 #ifdef BSD4_4 548 switch (family) { 549 case AF_INET: 550 case AF_INET6: 551 *portp = 0; 552 if (bindresvport(s, (struct sockaddr_in *)(void *)sa) < 0) { 553 int sverr = errno; 554 555 (void)close(s); 556 errno = sverr; 557 return (-1); 558 } 559 *alport = (int)ntohs(*portp); 560 return (s); 561 default: 562 /* is it necessary to try keep code for other AFs? */ 563 break; 564 } 565 #endif 566 for (;;) { 567 *portp = htons((u_short)*alport); 568 if (bind(s, sa, (socklen_t)salen) >= 0) 569 return (s); 570 if (errno != EADDRINUSE) { 571 (void)close(s); 572 return (-1); 573 } 574 (*alport)--; 575 if (*alport == IPPORT_RESERVED/2) { 576 (void)close(s); 577 errno = EAGAIN; /* close */ 578 return (-1); 579 } 580 } 581 } 582 583 int __check_rhosts_file = 1; 584 const char *__rcmd_errstr; 585 586 int 587 ruserok(rhost, superuser, ruser, luser) 588 const char *rhost, *ruser, *luser; 589 int superuser; 590 { 591 struct addrinfo hints, *res, *r; 592 int error; 593 594 _DIAGASSERT(rhost != NULL); 595 _DIAGASSERT(ruser != NULL); 596 _DIAGASSERT(luser != NULL); 597 598 memset(&hints, 0, sizeof(hints)); 599 hints.ai_family = PF_UNSPEC; 600 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 601 error = getaddrinfo(rhost, "0", &hints, &res); 602 if (error) 603 return (-1); 604 605 for (r = res; r; r = r->ai_next) { 606 if (iruserok_sa(r->ai_addr, (int)r->ai_addrlen, superuser, 607 ruser, luser) == 0) { 608 freeaddrinfo(res); 609 return (0); 610 } 611 } 612 freeaddrinfo(res); 613 return (-1); 614 } 615 616 /* 617 * New .rhosts strategy: We are passed an ip address. We spin through 618 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 619 * has ip addresses, we don't have to trust a nameserver. When it 620 * contains hostnames, we spin through the list of addresses the nameserver 621 * gives us and look for a match. 622 * 623 * Returns 0 if ok, -1 if not ok. 624 */ 625 int 626 iruserok(raddr, superuser, ruser, luser) 627 u_int32_t raddr; 628 int superuser; 629 const char *ruser, *luser; 630 { 631 struct sockaddr_in irsin; 632 633 memset(&irsin, 0, sizeof(irsin)); 634 irsin.sin_family = AF_INET; 635 #ifdef BSD4_4 636 irsin.sin_len = sizeof(struct sockaddr_in); 637 #endif 638 memcpy(&irsin.sin_addr, &raddr, sizeof(irsin.sin_addr)); 639 return iruserok_sa(&irsin, sizeof(struct sockaddr_in), superuser, ruser, 640 luser); 641 } 642 643 /* 644 * 2nd and 3rd arguments are typed like this, to avoid dependency between 645 * unistd.h and sys/socket.h. There's no better way. 646 */ 647 int 648 iruserok_sa(raddr, rlen, superuser, ruser, luser) 649 const void *raddr; 650 int rlen; 651 int superuser; 652 const char *ruser, *luser; 653 { 654 const struct sockaddr *sa; 655 struct stat sbuf; 656 struct passwd *pwd, pwres; 657 FILE *hostf; 658 uid_t uid; 659 gid_t gid; 660 int isvaliduser; 661 char pbuf[MAXPATHLEN]; 662 char pwbuf[1024]; 663 664 _DIAGASSERT(raddr != NULL); 665 _DIAGASSERT(ruser != NULL); 666 _DIAGASSERT(luser != NULL); 667 668 sa = raddr; 669 670 __rcmd_errstr = NULL; 671 672 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 673 674 if (hostf) { 675 if (__ivaliduser_sa(hostf, sa, (socklen_t)rlen, luser, 676 ruser) == 0) { 677 (void)fclose(hostf); 678 return (0); 679 } 680 (void)fclose(hostf); 681 } 682 683 isvaliduser = -1; 684 if (__check_rhosts_file || superuser) { 685 686 if (getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 687 || pwd == NULL) 688 return (-1); 689 (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf)); 690 (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf)); 691 692 /* 693 * Change effective uid while opening and reading .rhosts. 694 * If root and reading an NFS mounted file system, can't 695 * read files that are protected read/write owner only. 696 */ 697 uid = geteuid(); 698 gid = getegid(); 699 (void)setegid(pwd->pw_gid); 700 initgroups(pwd->pw_name, pwd->pw_gid); 701 (void)seteuid(pwd->pw_uid); 702 hostf = fopen(pbuf, "r"); 703 704 if (hostf != NULL) { 705 /* 706 * If not a regular file, or is owned by someone other 707 * than user or root or if writable by anyone but the 708 * owner, quit. 709 */ 710 if (lstat(pbuf, &sbuf) < 0) 711 __rcmd_errstr = ".rhosts lstat failed"; 712 else if (!S_ISREG(sbuf.st_mode)) 713 __rcmd_errstr = ".rhosts not regular file"; 714 else if (fstat(fileno(hostf), &sbuf) < 0) 715 __rcmd_errstr = ".rhosts fstat failed"; 716 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 717 __rcmd_errstr = "bad .rhosts owner"; 718 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 719 __rcmd_errstr = 720 ".rhosts writable by other than owner"; 721 else 722 isvaliduser = 723 __ivaliduser_sa(hostf, sa, (socklen_t)rlen, 724 luser, ruser); 725 726 (void)fclose(hostf); 727 } 728 (void)seteuid(uid); 729 (void)setegid(gid); 730 731 } 732 return (isvaliduser); 733 } 734 735 /* 736 * XXX 737 * Don't make static, used by lpd(8). We will be able to change the function 738 * into static function, when we bump libc major #. 739 * 740 * Returns 0 if ok, -1 if not ok. 741 */ 742 #ifdef notdef /*_LIBC*/ 743 static 744 #endif 745 int 746 __ivaliduser(hostf, raddr, luser, ruser) 747 FILE *hostf; 748 u_int32_t raddr; 749 const char *luser, *ruser; 750 { 751 struct sockaddr_in ivusin; 752 753 memset(&ivusin, 0, sizeof(ivusin)); 754 ivusin.sin_family = AF_INET; 755 #ifdef BSD4_4 756 ivusin.sin_len = sizeof(struct sockaddr_in); 757 #endif 758 memcpy(&ivusin.sin_addr, &raddr, sizeof(ivusin.sin_addr)); 759 return __ivaliduser_sa(hostf, (struct sockaddr *)(void *)&ivusin, 760 sizeof(struct sockaddr_in), luser, ruser); 761 } 762 763 #ifdef notdef /*_LIBC*/ 764 static 765 #endif 766 int 767 __ivaliduser_sa(hostf, raddr, salen, luser, ruser) 768 FILE *hostf; 769 const struct sockaddr *raddr; 770 socklen_t salen; 771 const char *luser, *ruser; 772 { 773 register char *user, *p; 774 int ch; 775 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 776 const char *auser, *ahost; 777 int hostok, userok; 778 char *rhost = NULL; 779 int firsttime = 1; 780 char domain[MAXHOSTNAMELEN]; 781 782 getdomainname(domain, sizeof(domain)); 783 784 _DIAGASSERT(hostf != NULL); 785 _DIAGASSERT(luser != NULL); 786 _DIAGASSERT(ruser != NULL); 787 788 while (fgets(buf, sizeof(buf), hostf)) { 789 p = buf; 790 /* Skip lines that are too long. */ 791 if (strchr(p, '\n') == NULL) { 792 while ((ch = getc(hostf)) != '\n' && ch != EOF) 793 ; 794 continue; 795 } 796 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 797 *p = isupper((unsigned char)*p) ? 798 tolower((unsigned char)*p) : *p; 799 p++; 800 } 801 if (*p == ' ' || *p == '\t') { 802 *p++ = '\0'; 803 while (*p == ' ' || *p == '\t') 804 p++; 805 user = p; 806 while (*p != '\n' && *p != ' ' && 807 *p != '\t' && *p != '\0') 808 p++; 809 } else 810 user = p; 811 *p = '\0'; 812 813 if (p == buf) 814 continue; 815 816 auser = *user ? user : luser; 817 ahost = buf; 818 819 if (ahost[0] == '+') 820 switch (ahost[1]) { 821 case '\0': 822 hostok = 1; 823 break; 824 825 case '@': 826 if (firsttime) { 827 rhost = __gethostloop(raddr, salen); 828 firsttime = 0; 829 } 830 if (rhost) 831 hostok = innetgr(&ahost[2], rhost, 832 NULL, domain); 833 else 834 hostok = 0; 835 break; 836 837 default: 838 hostok = __icheckhost(raddr, salen, &ahost[1]); 839 break; 840 } 841 else if (ahost[0] == '-') 842 switch (ahost[1]) { 843 case '\0': 844 hostok = -1; 845 break; 846 847 case '@': 848 if (firsttime) { 849 rhost = __gethostloop(raddr, salen); 850 firsttime = 0; 851 } 852 if (rhost) 853 hostok = -innetgr(&ahost[2], rhost, 854 NULL, domain); 855 else 856 hostok = 0; 857 break; 858 859 default: 860 hostok = -__icheckhost(raddr, salen, &ahost[1]); 861 break; 862 } 863 else 864 hostok = __icheckhost(raddr, salen, ahost); 865 866 867 if (auser[0] == '+') 868 switch (auser[1]) { 869 case '\0': 870 userok = 1; 871 break; 872 873 case '@': 874 userok = innetgr(&auser[2], NULL, ruser, 875 domain); 876 break; 877 878 default: 879 userok = strcmp(ruser, &auser[1]) == 0; 880 break; 881 } 882 else if (auser[0] == '-') 883 switch (auser[1]) { 884 case '\0': 885 userok = -1; 886 break; 887 888 case '@': 889 userok = -innetgr(&auser[2], NULL, ruser, 890 domain); 891 break; 892 893 default: 894 userok = 895 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 896 break; 897 } 898 else 899 userok = strcmp(ruser, auser) == 0; 900 901 /* Check if one component did not match */ 902 if (hostok == 0 || userok == 0) 903 continue; 904 905 /* Check if we got a forbidden pair */ 906 if (userok == -1 || hostok == -1) 907 return -1; 908 909 /* Check if we got a valid pair */ 910 if (hostok == 1 && userok == 1) 911 return 0; 912 } 913 return -1; 914 } 915 916 /* 917 * Returns "true" if match, 0 if no match. 918 */ 919 static int 920 __icheckhost(raddr, salen, lhost) 921 const struct sockaddr *raddr; 922 socklen_t salen; 923 const char *lhost; 924 { 925 struct addrinfo hints, *res, *r; 926 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 927 int error; 928 const int niflags = NI_NUMERICHOST; 929 930 _DIAGASSERT(raddr != NULL); 931 _DIAGASSERT(lhost != NULL); 932 933 h1[0] = '\0'; 934 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, 935 niflags) != 0) 936 return (0); 937 938 /* Resolve laddr into sockaddr */ 939 memset(&hints, 0, sizeof(hints)); 940 hints.ai_family = raddr->sa_family; 941 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 942 res = NULL; 943 error = getaddrinfo(lhost, "0", &hints, &res); 944 if (error) 945 return (0); 946 947 /* 948 * Try string comparisons between raddr and laddr. 949 */ 950 for (r = res; r; r = r->ai_next) { 951 h2[0] = '\0'; 952 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 953 NULL, 0, niflags) != 0) 954 continue; 955 if (strcmp(h1, h2) == 0) { 956 freeaddrinfo(res); 957 return (1); 958 } 959 } 960 961 /* No match. */ 962 freeaddrinfo(res); 963 return (0); 964 } 965 966 /* 967 * Return the hostname associated with the supplied address. 968 * Do a reverse lookup as well for security. If a loop cannot 969 * be found, pack the numeric IP address into the string. 970 */ 971 static char * 972 __gethostloop(raddr, salen) 973 const struct sockaddr *raddr; 974 socklen_t salen; 975 { 976 static char remotehost[NI_MAXHOST]; 977 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 978 struct addrinfo hints, *res, *r; 979 int error; 980 const int niflags = NI_NUMERICHOST; 981 982 _DIAGASSERT(raddr != NULL); 983 984 h1[0] = remotehost[0] = '\0'; 985 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost), 986 NULL, 0, NI_NAMEREQD) != 0) 987 return (NULL); 988 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, 989 niflags) != 0) 990 return (NULL); 991 992 /* 993 * Look up the name and check that the supplied 994 * address is in the list 995 */ 996 memset(&hints, 0, sizeof(hints)); 997 hints.ai_family = raddr->sa_family; 998 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 999 hints.ai_flags = AI_CANONNAME; 1000 res = NULL; 1001 error = getaddrinfo(remotehost, "0", &hints, &res); 1002 if (error) 1003 return (NULL); 1004 1005 for (r = res; r; r = r->ai_next) { 1006 h2[0] = '\0'; 1007 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 1008 NULL, 0, niflags) != 0) 1009 continue; 1010 if (strcmp(h1, h2) == 0) { 1011 freeaddrinfo(res); 1012 return (remotehost); 1013 } 1014 } 1015 1016 /* 1017 * either the DNS adminstrator has made a configuration 1018 * mistake, or someone has attempted to spoof us 1019 */ 1020 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 1021 h1, res->ai_canonname ? res->ai_canonname : remotehost); 1022 freeaddrinfo(res); 1023 return (NULL); 1024 } 1025