1 /* $NetBSD: rcmd.c,v 1.67 2012/03/13 21:13:42 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 1.67 2012/03/13 21:13:42 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(char **, u_int, const char *, const char *, const char *, int *); 74 int orcmd_af(char **, u_int, const char *, const char *, const char *, 75 int *, int); 76 int __ivaliduser(FILE *, u_int32_t, const char *, const char *); 77 int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, 78 const char *, const char *); 79 static int rshrcmd(int, char **, u_int32_t, const char *, 80 const char *, const char *, int *, const char *); 81 static int resrcmd(struct addrinfo *, char **, u_int32_t, const char *, 82 const char *, const char *, int *); 83 static int __icheckhost(const struct sockaddr *, socklen_t, 84 const char *); 85 static char *__gethostloop(const struct sockaddr *, socklen_t); 86 87 int 88 rcmd(char **ahost, int rport, const char *locuser, const char *remuser, 89 const char *cmd, int *fd2p) 90 { 91 92 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 93 } 94 95 int 96 rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser, 97 const char *cmd, int *fd2p, int af) 98 { 99 static char hbuf[MAXHOSTNAMELEN]; 100 char pbuf[NI_MAXSERV]; 101 struct addrinfo hints, *res; 102 int error; 103 struct servent *sp; 104 105 _DIAGASSERT(ahost != NULL); 106 _DIAGASSERT(locuser != NULL); 107 _DIAGASSERT(remuser != NULL); 108 _DIAGASSERT(cmd != NULL); 109 /* fd2p may be NULL */ 110 111 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 112 memset(&hints, 0, sizeof(hints)); 113 hints.ai_family = af; 114 hints.ai_socktype = SOCK_STREAM; 115 hints.ai_flags = AI_CANONNAME; 116 error = getaddrinfo(*ahost, pbuf, &hints, &res); 117 if (error) { 118 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 119 return -1; 120 } 121 if (res->ai_canonname) { 122 /* 123 * Canonicalise hostname. 124 * XXX: Should we really do this? 125 */ 126 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 127 *ahost = hbuf; 128 } 129 130 /* 131 * Check if rport is the same as the shell port, and that the fd2p. If 132 * it is not, the program isn't expecting 'rsh' and so we can't use the 133 * RCMD_CMD environment. 134 */ 135 sp = getservbyname("shell", "tcp"); 136 if (sp != NULL && sp->s_port == rport) 137 error = rshrcmd(af, ahost, (u_int32_t)rport, 138 locuser, remuser, cmd, fd2p, getenv("RCMD_CMD")); 139 else 140 error = resrcmd(res, ahost, (u_int32_t)rport, 141 locuser, remuser, cmd, fd2p); 142 freeaddrinfo(res); 143 return error; 144 } 145 146 /* this is simply a wrapper around hprcmd() that handles ahost first */ 147 int 148 orcmd(char **ahost, u_int rport, const char *locuser, const char *remuser, 149 const char *cmd, int *fd2p) 150 { 151 return orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 152 } 153 154 int 155 orcmd_af(char **ahost, u_int rport, const char *locuser, const char *remuser, 156 const char *cmd, int *fd2p, int af) 157 { 158 static char hbuf[MAXHOSTNAMELEN]; 159 char pbuf[NI_MAXSERV]; 160 struct addrinfo hints, *res; 161 int error; 162 163 _DIAGASSERT(ahost != NULL); 164 _DIAGASSERT(locuser != NULL); 165 _DIAGASSERT(remuser != NULL); 166 _DIAGASSERT(cmd != NULL); 167 /* fd2p may be NULL */ 168 169 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 170 memset(&hints, 0, sizeof(hints)); 171 hints.ai_family = af; 172 hints.ai_socktype = SOCK_STREAM; 173 hints.ai_flags = AI_CANONNAME; 174 error = getaddrinfo(*ahost, pbuf, &hints, &res); 175 if (error) { 176 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 177 return -1; 178 } 179 if (res->ai_canonname) { 180 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 181 *ahost = hbuf; 182 } 183 184 error = resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p); 185 freeaddrinfo(res); 186 return error; 187 } 188 189 /*ARGSUSED*/ 190 static int 191 resrcmd(struct addrinfo *res, char **ahost, u_int32_t rport, 192 const char *locuser, const char *remuser, const char *cmd, int *fd2p) 193 { 194 struct addrinfo *r; 195 struct sockaddr_storage from; 196 struct pollfd reads[2]; 197 sigset_t nmask, omask; 198 pid_t pid; 199 int s, lport, timo; 200 int pollr; 201 char c; 202 int refused; 203 204 _DIAGASSERT(res != NULL); 205 _DIAGASSERT(ahost != NULL); 206 _DIAGASSERT(locuser != NULL); 207 _DIAGASSERT(remuser != NULL); 208 _DIAGASSERT(cmd != NULL); 209 /* fd2p may be NULL */ 210 211 r = res; 212 refused = 0; 213 pid = getpid(); 214 sigemptyset(&nmask); 215 sigaddset(&nmask, SIGURG); 216 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) 217 return -1; 218 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 219 s = rresvport_af(&lport, r->ai_family); 220 if (s < 0) { 221 if (errno == EAGAIN) 222 warnx("rcmd: socket: All ports in use"); 223 else 224 warn("rcmd: socket"); 225 if (r->ai_next) { 226 r = r->ai_next; 227 continue; 228 } else { 229 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 230 return -1; 231 } 232 } 233 fcntl(s, F_SETOWN, pid); 234 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 235 break; 236 (void)close(s); 237 if (errno == EADDRINUSE) { 238 lport--; 239 continue; 240 } else if (errno == ECONNREFUSED) 241 refused++; 242 if (r->ai_next) { 243 int oerrno = errno; 244 char hbuf[NI_MAXHOST]; 245 const int niflags = NI_NUMERICHOST; 246 247 hbuf[0] = '\0'; 248 if (getnameinfo(r->ai_addr, r->ai_addrlen, 249 hbuf, (socklen_t)sizeof(hbuf), NULL, 0, niflags) != 250 0) 251 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 252 errno = oerrno; 253 warn("rcmd: connect to address %s", hbuf); 254 r = r->ai_next; 255 hbuf[0] = '\0'; 256 if (getnameinfo(r->ai_addr, r->ai_addrlen, 257 hbuf, (socklen_t)sizeof(hbuf), NULL, 0, niflags) != 258 0) 259 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 260 (void)fprintf(stderr, "Trying %s...\n", hbuf); 261 continue; 262 } 263 if (refused && timo <= 16) { 264 (void)sleep((unsigned int)timo); 265 timo *= 2; 266 r = res; 267 refused = 0; 268 continue; 269 } 270 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 271 strerror(errno)); 272 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 273 return -1; 274 } 275 lport--; 276 if (fd2p == 0) { 277 write(s, "", 1); 278 lport = 0; 279 } else { 280 char num[8]; 281 int s2 = rresvport_af(&lport, r->ai_family), s3; 282 socklen_t len = sizeof(from); 283 284 if (s2 < 0) 285 goto bad; 286 listen(s2, 1); 287 (void)snprintf(num, sizeof(num), "%d", lport); 288 if (write(s, num, strlen(num) + 1) != 289 (ssize_t) (strlen(num) + 1)) { 290 warn("rcmd: write (setting up stderr)"); 291 (void)close(s2); 292 goto bad; 293 } 294 reads[0].fd = s; 295 reads[0].events = POLLIN; 296 reads[1].fd = s2; 297 reads[1].events = POLLIN; 298 errno = 0; 299 pollr = poll(reads, 2, INFTIM); 300 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 301 if (errno != 0) 302 warn("poll: setting up stderr"); 303 else 304 warnx( 305 "poll: protocol failure in circuit setup"); 306 (void)close(s2); 307 goto bad; 308 } 309 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 310 (void)close(s2); 311 if (s3 < 0) { 312 warn("rcmd: accept"); 313 lport = 0; 314 goto bad; 315 } 316 *fd2p = s3; 317 switch (((struct sockaddr *)(void *)&from)->sa_family) { 318 case AF_INET: 319 #ifdef INET6 320 case AF_INET6: 321 #endif 322 if (getnameinfo((struct sockaddr *)(void *)&from, len, 323 NULL, 0, num, (socklen_t)sizeof(num), 324 NI_NUMERICSERV) != 0 || 325 (atoi(num) >= IPPORT_RESERVED || 326 atoi(num) < IPPORT_RESERVED / 2)) { 327 warnx( 328 "rcmd: protocol failure in circuit setup."); 329 goto bad2; 330 } 331 break; 332 default: 333 break; 334 } 335 } 336 337 (void)write(s, locuser, strlen(locuser)+1); 338 (void)write(s, remuser, strlen(remuser)+1); 339 (void)write(s, cmd, strlen(cmd)+1); 340 if (read(s, &c, 1) != 1) { 341 warn("%s", *ahost); 342 goto bad2; 343 } 344 if (c != 0) { 345 while (read(s, &c, 1) == 1) { 346 (void)write(STDERR_FILENO, &c, 1); 347 if (c == '\n') 348 break; 349 } 350 goto bad2; 351 } 352 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 353 return s; 354 bad2: 355 if (lport) 356 (void)close(*fd2p); 357 bad: 358 (void)close(s); 359 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 360 return -1; 361 } 362 363 /* 364 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 365 */ 366 /* ARGSUSED */ 367 static int 368 rshrcmd(int af, char **ahost, u_int32_t rport, const char *locuser, 369 const char *remuser, const char *cmd, int *fd2p, const char *rshcmd) 370 { 371 pid_t pid; 372 int sp[2], ep[2]; 373 char *p; 374 struct passwd *pw, pwres; 375 char pwbuf[1024]; 376 377 _DIAGASSERT(ahost != NULL); 378 _DIAGASSERT(locuser != NULL); 379 _DIAGASSERT(remuser != NULL); 380 _DIAGASSERT(cmd != NULL); 381 /* fd2p may be NULL */ 382 383 /* What rsh/shell to use. */ 384 if (rshcmd == NULL) 385 rshcmd = _PATH_BIN_RCMD; 386 387 /* locuser must exist on this host. */ 388 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || 389 pw == NULL) { 390 warnx("%s: unknown user: %s", __func__, locuser); 391 return -1; 392 } 393 394 /* get a socketpair we'll use for stdin and stdout. */ 395 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 396 warn("%s: socketpair", __func__); 397 return -1; 398 } 399 /* we will use this for the fd2 pointer */ 400 if (fd2p) { 401 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 402 warn("%s: socketpair", __func__); 403 return -1; 404 } 405 *fd2p = ep[0]; 406 } 407 408 pid = fork(); 409 if (pid < 0) { 410 warn("%s: fork", __func__); 411 return -1; 412 } 413 if (pid == 0) { 414 /* 415 * child 416 * - we use sp[1] to be stdin/stdout, and close sp[0] 417 * - with fd2p, we use ep[1] for stderr, and close ep[0] 418 */ 419 (void)close(sp[0]); 420 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 421 warn("%s: dup2", __func__); 422 _exit(1); 423 } 424 (void)close(sp[1]); 425 if (fd2p) { 426 if (dup2(ep[1], 2) < 0) { 427 warn("%s: dup2", __func__); 428 _exit(1); 429 } 430 (void)close(ep[0]); 431 (void)close(ep[1]); 432 } else if (dup2(0, 2) < 0) { 433 warn("%s: dup2", __func__); 434 _exit(1); 435 } 436 /* fork again to lose parent. */ 437 pid = fork(); 438 if (pid < 0) { 439 warn("%s: second fork", __func__); 440 _exit(1); 441 } 442 if (pid > 0) 443 _exit(0); 444 445 /* Orphan. Become local user for rshprog. */ 446 if (setuid(pw->pw_uid)) { 447 warn("%s: setuid(%lu)", __func__, (u_long)pw->pw_uid); 448 _exit(1); 449 } 450 451 /* 452 * If we are rcmd'ing to "localhost" as the same user as we 453 * are, then avoid running remote shell for efficiency. 454 */ 455 if (strcmp(*ahost, "localhost") == 0 && 456 strcmp(locuser, remuser) == 0) { 457 if (pw->pw_shell[0] == '\0') 458 rshcmd = _PATH_BSHELL; 459 else 460 rshcmd = pw->pw_shell; 461 p = strrchr(rshcmd, '/'); 462 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 463 } else { 464 const char *program; 465 program = strrchr(rshcmd, '/'); 466 program = program ? program + 1 : rshcmd; 467 switch (af) { 468 case AF_INET: 469 execlp(rshcmd, program, "-4", "-l", remuser, 470 *ahost, cmd, NULL); 471 break; 472 473 case AF_INET6: 474 execlp(rshcmd, program, "-6", "-l", remuser, 475 *ahost, cmd, NULL); 476 break; 477 478 default: 479 /* typically AF_UNSPEC, plus whatever */ 480 execlp(rshcmd, program, "-l", remuser, 481 *ahost, cmd, NULL); 482 break; 483 } 484 } 485 warn("%s: exec %s", __func__, 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(int *alport) 499 { 500 501 _DIAGASSERT(alport != NULL); 502 503 return rresvport_af(alport, AF_INET); 504 } 505 506 int 507 rresvport_af(int *alport, int family) 508 { 509 struct sockaddr_storage ss; 510 struct sockaddr *sa; 511 socklen_t salen; 512 int s; 513 u_int16_t *portp; 514 515 _DIAGASSERT(alport != NULL); 516 517 memset(&ss, 0, sizeof(ss)); 518 sa = (struct sockaddr *)(void *)&ss; 519 switch (family) { 520 case AF_INET: 521 #ifdef BSD4_4 522 sa->sa_len = 523 #endif 524 salen = sizeof(struct sockaddr_in); 525 portp = &((struct sockaddr_in *)(void *)sa)->sin_port; 526 break; 527 #ifdef INET6 528 case AF_INET6: 529 #ifdef BSD4_4 530 sa->sa_len = 531 #endif 532 salen = sizeof(struct sockaddr_in6); 533 portp = &((struct sockaddr_in6 *)(void *)sa)->sin6_port; 534 break; 535 #endif 536 default: 537 errno = EAFNOSUPPORT; 538 return -1; 539 } 540 sa->sa_family = family; 541 s = socket(family, SOCK_STREAM, 0); 542 if (s < 0) 543 return -1; 544 #ifdef BSD4_4 545 switch (family) { 546 case AF_INET: 547 case AF_INET6: 548 *portp = 0; 549 if (bindresvport(s, (struct sockaddr_in *)(void *)sa) < 0) { 550 int sverr = errno; 551 552 (void)close(s); 553 errno = sverr; 554 return -1; 555 } 556 *alport = (int)ntohs(*portp); 557 return s; 558 default: 559 /* is it necessary to try keep code for other AFs? */ 560 break; 561 } 562 #endif 563 for (;;) { 564 *portp = htons((u_short)*alport); 565 if (bind(s, sa, salen) >= 0) 566 return s; 567 if (errno != EADDRINUSE) { 568 (void)close(s); 569 return -1; 570 } 571 (*alport)--; 572 if (*alport == IPPORT_RESERVED/2) { 573 (void)close(s); 574 errno = EAGAIN; /* close */ 575 return -1; 576 } 577 } 578 } 579 580 int __check_rhosts_file = 1; 581 const char *__rcmd_errstr; 582 583 int 584 ruserok(const char *rhost, int superuser, const char *ruser, const char *luser) 585 { 586 struct addrinfo hints, *res, *r; 587 int error; 588 589 _DIAGASSERT(rhost != NULL); 590 _DIAGASSERT(ruser != NULL); 591 _DIAGASSERT(luser != NULL); 592 593 memset(&hints, 0, sizeof(hints)); 594 hints.ai_family = PF_UNSPEC; 595 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 596 error = getaddrinfo(rhost, "0", &hints, &res); 597 if (error) 598 return -1; 599 600 for (r = res; r; r = r->ai_next) { 601 if (iruserok_sa(r->ai_addr, (int)r->ai_addrlen, superuser, 602 ruser, luser) == 0) { 603 freeaddrinfo(res); 604 return 0; 605 } 606 } 607 freeaddrinfo(res); 608 return -1; 609 } 610 611 /* 612 * New .rhosts strategy: We are passed an ip address. We spin through 613 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 614 * has ip addresses, we don't have to trust a nameserver. When it 615 * contains hostnames, we spin through the list of addresses the nameserver 616 * gives us and look for a match. 617 * 618 * Returns 0 if ok, -1 if not ok. 619 */ 620 int 621 iruserok(u_int32_t raddr, int superuser, const char *ruser, const char *luser) 622 { 623 struct sockaddr_in irsin; 624 625 memset(&irsin, 0, sizeof(irsin)); 626 irsin.sin_family = AF_INET; 627 #ifdef BSD4_4 628 irsin.sin_len = sizeof(irsin); 629 #endif 630 memcpy(&irsin.sin_addr, &raddr, sizeof(irsin.sin_addr)); 631 return iruserok_sa(&irsin, (socklen_t)sizeof(irsin), superuser, ruser, 632 luser); 633 } 634 635 /* 636 * 2nd and 3rd arguments are typed like this, to avoid dependency between 637 * unistd.h and sys/socket.h. There's no better way. 638 */ 639 int 640 iruserok_sa(const void *raddr, int rlen, int superuser, const char *ruser, 641 const char *luser) 642 { 643 const struct sockaddr *sa; 644 struct stat sbuf; 645 struct passwd *pwd, pwres; 646 FILE *hostf; 647 uid_t uid; 648 gid_t gid; 649 int isvaliduser; 650 char pbuf[MAXPATHLEN]; 651 char pwbuf[1024]; 652 653 _DIAGASSERT(raddr != NULL); 654 _DIAGASSERT(ruser != NULL); 655 _DIAGASSERT(luser != NULL); 656 657 sa = raddr; 658 659 __rcmd_errstr = NULL; 660 661 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 662 663 if (hostf) { 664 if (__ivaliduser_sa(hostf, sa, (socklen_t)rlen, luser, 665 ruser) == 0) { 666 (void)fclose(hostf); 667 return 0; 668 } 669 (void)fclose(hostf); 670 } 671 672 isvaliduser = -1; 673 if (__check_rhosts_file || superuser) { 674 675 if (getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 676 || pwd == NULL) 677 return -1; 678 (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf)); 679 (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf)); 680 681 /* 682 * Change effective uid while opening and reading .rhosts. 683 * If root and reading an NFS mounted file system, can't 684 * read files that are protected read/write owner only. 685 */ 686 uid = geteuid(); 687 gid = getegid(); 688 (void)setegid(pwd->pw_gid); 689 initgroups(pwd->pw_name, pwd->pw_gid); 690 (void)seteuid(pwd->pw_uid); 691 hostf = fopen(pbuf, "r"); 692 693 if (hostf != NULL) { 694 /* 695 * If not a regular file, or is owned by someone other 696 * than user or root or if writable by anyone but the 697 * owner, quit. 698 */ 699 if (lstat(pbuf, &sbuf) < 0) 700 __rcmd_errstr = ".rhosts lstat failed"; 701 else if (!S_ISREG(sbuf.st_mode)) 702 __rcmd_errstr = ".rhosts not regular file"; 703 else if (fstat(fileno(hostf), &sbuf) < 0) 704 __rcmd_errstr = ".rhosts fstat failed"; 705 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 706 __rcmd_errstr = "bad .rhosts owner"; 707 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 708 __rcmd_errstr = 709 ".rhosts writable by other than owner"; 710 else 711 isvaliduser = 712 __ivaliduser_sa(hostf, sa, (socklen_t)rlen, 713 luser, ruser); 714 715 (void)fclose(hostf); 716 } 717 (void)seteuid(uid); 718 (void)setegid(gid); 719 720 } 721 return isvaliduser; 722 } 723 724 /* 725 * XXX 726 * Don't make static, used by lpd(8). We will be able to change the function 727 * into static function, when we bump libc major #. 728 * 729 * Returns 0 if ok, -1 if not ok. 730 */ 731 #ifdef notdef /*_LIBC*/ 732 static 733 #endif 734 int 735 __ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, 736 const char *ruser) 737 { 738 struct sockaddr_in ivusin; 739 740 memset(&ivusin, 0, sizeof(ivusin)); 741 ivusin.sin_family = AF_INET; 742 #ifdef BSD4_4 743 ivusin.sin_len = sizeof(ivusin); 744 #endif 745 memcpy(&ivusin.sin_addr, &raddr, sizeof(ivusin.sin_addr)); 746 return __ivaliduser_sa(hostf, (struct sockaddr *)(void *)&ivusin, 747 (socklen_t)sizeof(ivusin), luser, ruser); 748 } 749 750 #ifdef notdef /*_LIBC*/ 751 static 752 #endif 753 int 754 __ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen, 755 const char *luser, const char *ruser) 756 { 757 char *user, *p; 758 int ch; 759 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 760 const char *auser, *ahost; 761 int hostok, userok; 762 char *rhost = NULL; 763 int firsttime = 1; 764 char domain[MAXHOSTNAMELEN]; 765 766 getdomainname(domain, sizeof(domain)); 767 768 _DIAGASSERT(hostf != NULL); 769 _DIAGASSERT(luser != NULL); 770 _DIAGASSERT(ruser != NULL); 771 772 while (fgets(buf, (int)sizeof(buf), hostf)) { 773 p = buf; 774 /* Skip lines that are too long. */ 775 if (strchr(p, '\n') == NULL) { 776 while ((ch = getc(hostf)) != '\n' && ch != EOF) 777 ; 778 continue; 779 } 780 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 781 *p = isupper((unsigned char)*p) ? 782 tolower((unsigned char)*p) : *p; 783 p++; 784 } 785 if (*p == ' ' || *p == '\t') { 786 *p++ = '\0'; 787 while (*p == ' ' || *p == '\t') 788 p++; 789 user = p; 790 while (*p != '\n' && *p != ' ' && 791 *p != '\t' && *p != '\0') 792 p++; 793 } else 794 user = p; 795 *p = '\0'; 796 797 if (p == buf) 798 continue; 799 800 auser = *user ? user : luser; 801 ahost = buf; 802 803 if (ahost[0] == '+') 804 switch (ahost[1]) { 805 case '\0': 806 hostok = 1; 807 break; 808 809 case '@': 810 if (firsttime) { 811 rhost = __gethostloop(raddr, salen); 812 firsttime = 0; 813 } 814 if (rhost) 815 hostok = innetgr(&ahost[2], rhost, 816 NULL, domain); 817 else 818 hostok = 0; 819 break; 820 821 default: 822 hostok = __icheckhost(raddr, salen, &ahost[1]); 823 break; 824 } 825 else if (ahost[0] == '-') 826 switch (ahost[1]) { 827 case '\0': 828 hostok = -1; 829 break; 830 831 case '@': 832 if (firsttime) { 833 rhost = __gethostloop(raddr, salen); 834 firsttime = 0; 835 } 836 if (rhost) 837 hostok = -innetgr(&ahost[2], rhost, 838 NULL, domain); 839 else 840 hostok = 0; 841 break; 842 843 default: 844 hostok = 845 -__icheckhost(raddr, salen, &ahost[1]); 846 break; 847 } 848 else 849 hostok = __icheckhost(raddr, salen, ahost); 850 851 852 if (auser[0] == '+') 853 switch (auser[1]) { 854 case '\0': 855 userok = 1; 856 break; 857 858 case '@': 859 userok = innetgr(&auser[2], NULL, ruser, 860 domain); 861 break; 862 863 default: 864 userok = strcmp(ruser, &auser[1]) == 0; 865 break; 866 } 867 else 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 = 880 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 881 break; 882 } 883 else 884 userok = strcmp(ruser, auser) == 0; 885 886 /* Check if one component did not match */ 887 if (hostok == 0 || userok == 0) 888 continue; 889 890 /* Check if we got a forbidden pair */ 891 if (userok == -1 || hostok == -1) 892 return -1; 893 894 /* Check if we got a valid pair */ 895 if (hostok == 1 && userok == 1) 896 return 0; 897 } 898 return -1; 899 } 900 901 /* 902 * Returns "true" if match, 0 if no match. 903 */ 904 static int 905 __icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost) 906 { 907 struct addrinfo hints, *res, *r; 908 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 909 int error; 910 const int niflags = NI_NUMERICHOST; 911 912 _DIAGASSERT(raddr != NULL); 913 _DIAGASSERT(lhost != NULL); 914 915 h1[0] = '\0'; 916 if (getnameinfo(raddr, salen, h1, (socklen_t)sizeof(h1), NULL, 0, 917 niflags) != 0) 918 return 0; 919 920 /* Resolve laddr into sockaddr */ 921 memset(&hints, 0, sizeof(hints)); 922 hints.ai_family = raddr->sa_family; 923 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 924 res = NULL; 925 error = getaddrinfo(lhost, "0", &hints, &res); 926 if (error) 927 return 0; 928 929 /* 930 * Try string comparisons between raddr and laddr. 931 */ 932 for (r = res; r; r = r->ai_next) { 933 h2[0] = '\0'; 934 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, 935 (socklen_t)sizeof(h2), NULL, 0, niflags) != 0) 936 continue; 937 if (strcmp(h1, h2) == 0) { 938 freeaddrinfo(res); 939 return 1; 940 } 941 } 942 943 /* No match. */ 944 freeaddrinfo(res); 945 return 0; 946 } 947 948 /* 949 * Return the hostname associated with the supplied address. 950 * Do a reverse lookup as well for security. If a loop cannot 951 * be found, pack the numeric IP address into the string. 952 */ 953 static char * 954 __gethostloop(const struct sockaddr *raddr, socklen_t salen) 955 { 956 static char remotehost[NI_MAXHOST]; 957 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 958 struct addrinfo hints, *res, *r; 959 int error; 960 const int niflags = NI_NUMERICHOST; 961 962 _DIAGASSERT(raddr != NULL); 963 964 h1[0] = remotehost[0] = '\0'; 965 if (getnameinfo(raddr, salen, remotehost, (socklen_t)sizeof(remotehost), 966 NULL, 0, NI_NAMEREQD) != 0) 967 return NULL; 968 if (getnameinfo(raddr, salen, h1, (socklen_t)sizeof(h1), NULL, 0, 969 niflags) != 0) 970 return NULL; 971 972 /* 973 * Look up the name and check that the supplied 974 * address is in the list 975 */ 976 memset(&hints, 0, sizeof(hints)); 977 hints.ai_family = raddr->sa_family; 978 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 979 hints.ai_flags = AI_CANONNAME; 980 res = NULL; 981 error = getaddrinfo(remotehost, "0", &hints, &res); 982 if (error) 983 return NULL; 984 985 for (r = res; r; r = r->ai_next) { 986 h2[0] = '\0'; 987 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, 988 (socklen_t)sizeof(h2), NULL, 0, niflags) != 0) 989 continue; 990 if (strcmp(h1, h2) == 0) { 991 freeaddrinfo(res); 992 return remotehost; 993 } 994 } 995 996 /* 997 * either the DNS adminstrator has made a configuration 998 * mistake, or someone has attempted to spoof us 999 */ 1000 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 1001 h1, res->ai_canonname ? res->ai_canonname : remotehost); 1002 freeaddrinfo(res); 1003 return NULL; 1004 } 1005