1 /* $NetBSD: rcmd.c,v 1.71 2014/11/26 23:44:21 enami 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 1.71 2014/11/26 23:44:21 enami 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 #if !defined(__minix) 52 #include <rpc/rpc.h> 53 #endif /* !defined(__minix) */ 54 #include <arpa/inet.h> 55 #include <netgroup.h> 56 57 #include <assert.h> 58 #include <ctype.h> 59 #include <err.h> 60 #include <errno.h> 61 #include <fcntl.h> 62 #include <grp.h> 63 #include <netdb.h> 64 #include <paths.h> 65 #include <pwd.h> 66 #include <signal.h> 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <syslog.h> 71 #include <unistd.h> 72 73 #include "pathnames.h" 74 75 int orcmd(char **, u_int, const char *, const char *, const char *, int *); 76 int orcmd_af(char **, u_int, const char *, const char *, const char *, 77 int *, int); 78 int __ivaliduser(FILE *, u_int32_t, const char *, const char *); 79 int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, 80 const char *, const char *); 81 static int rshrcmd(int, char **, u_int32_t, const char *, 82 const char *, const char *, int *, const char *); 83 static int resrcmd(struct addrinfo *, char **, u_int32_t, const char *, 84 const char *, const char *, int *); 85 static int __icheckhost(const struct sockaddr *, socklen_t, 86 const char *); 87 static char *__gethostloop(const struct sockaddr *, socklen_t); 88 89 int 90 rcmd(char **ahost, int rport, const char *locuser, const char *remuser, 91 const char *cmd, int *fd2p) 92 { 93 94 return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 95 } 96 97 int 98 rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser, 99 const char *cmd, int *fd2p, int af) 100 { 101 static char hbuf[MAXHOSTNAMELEN]; 102 char pbuf[NI_MAXSERV]; 103 struct addrinfo hints, *res; 104 int error; 105 struct servent *sp; 106 107 _DIAGASSERT(ahost != NULL); 108 _DIAGASSERT(locuser != NULL); 109 _DIAGASSERT(remuser != NULL); 110 _DIAGASSERT(cmd != NULL); 111 /* fd2p may be NULL */ 112 113 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 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 121 return -1; 122 } 123 if (res->ai_canonname) { 124 /* 125 * Canonicalise hostname. 126 * XXX: Should we really do this? 127 */ 128 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 129 *ahost = hbuf; 130 } 131 132 /* 133 * Check if rport is the same as the shell port, and that the fd2p. If 134 * it is not, the program isn't expecting 'rsh' and so we can't use the 135 * RCMD_CMD environment. 136 */ 137 sp = getservbyname("shell", "tcp"); 138 if (sp != NULL && sp->s_port == rport) 139 error = rshrcmd(af, ahost, (u_int32_t)rport, 140 locuser, remuser, cmd, fd2p, getenv("RCMD_CMD")); 141 else 142 error = resrcmd(res, ahost, (u_int32_t)rport, 143 locuser, remuser, cmd, fd2p); 144 freeaddrinfo(res); 145 return error; 146 } 147 148 /* this is simply a wrapper around hprcmd() that handles ahost first */ 149 int 150 orcmd(char **ahost, u_int rport, const char *locuser, const char *remuser, 151 const char *cmd, int *fd2p) 152 { 153 return orcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET); 154 } 155 156 int 157 orcmd_af(char **ahost, u_int rport, const char *locuser, const char *remuser, 158 const char *cmd, int *fd2p, int af) 159 { 160 static char hbuf[MAXHOSTNAMELEN]; 161 char pbuf[NI_MAXSERV]; 162 struct addrinfo hints, *res; 163 int error; 164 165 _DIAGASSERT(ahost != NULL); 166 _DIAGASSERT(locuser != NULL); 167 _DIAGASSERT(remuser != NULL); 168 _DIAGASSERT(cmd != NULL); 169 /* fd2p may be NULL */ 170 171 snprintf(pbuf, sizeof(pbuf), "%u", ntohs(rport)); 172 memset(&hints, 0, sizeof(hints)); 173 hints.ai_family = af; 174 hints.ai_socktype = SOCK_STREAM; 175 hints.ai_flags = AI_CANONNAME; 176 error = getaddrinfo(*ahost, pbuf, &hints, &res); 177 if (error) { 178 warnx("%s: %s", *ahost, gai_strerror(error)); /*XXX*/ 179 return -1; 180 } 181 if (res->ai_canonname) { 182 strlcpy(hbuf, res->ai_canonname, sizeof(hbuf)); 183 *ahost = hbuf; 184 } 185 186 error = resrcmd(res, ahost, rport, locuser, remuser, cmd, fd2p); 187 freeaddrinfo(res); 188 return error; 189 } 190 191 /*ARGSUSED*/ 192 static int 193 resrcmd(struct addrinfo *res, char **ahost, u_int32_t rport, 194 const char *locuser, const char *remuser, const char *cmd, int *fd2p) 195 { 196 struct addrinfo *r; 197 struct sockaddr_storage from; 198 struct pollfd reads[2]; 199 sigset_t nmask, omask; 200 pid_t pid; 201 int s, lport, timo; 202 int pollr; 203 char c; 204 int refused; 205 206 _DIAGASSERT(res != NULL); 207 _DIAGASSERT(ahost != NULL); 208 _DIAGASSERT(locuser != NULL); 209 _DIAGASSERT(remuser != NULL); 210 _DIAGASSERT(cmd != NULL); 211 /* fd2p may be NULL */ 212 213 r = res; 214 refused = 0; 215 pid = getpid(); 216 sigemptyset(&nmask); 217 sigaddset(&nmask, SIGURG); 218 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) 219 return -1; 220 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 221 s = rresvport_af(&lport, r->ai_family); 222 if (s < 0) { 223 if (errno == EAGAIN) 224 warnx("rcmd: socket: All ports in use"); 225 else 226 warn("rcmd: socket"); 227 if (r->ai_next) { 228 r = r->ai_next; 229 continue; 230 } else { 231 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 232 return -1; 233 } 234 } 235 fcntl(s, F_SETOWN, pid); 236 if (connect(s, r->ai_addr, r->ai_addrlen) >= 0) 237 break; 238 (void)close(s); 239 if (errno == EADDRINUSE) { 240 lport--; 241 continue; 242 } else if (errno == ECONNREFUSED) 243 refused++; 244 if (r->ai_next) { 245 int oerrno = errno; 246 char hbuf[NI_MAXHOST]; 247 const int niflags = NI_NUMERICHOST; 248 249 hbuf[0] = '\0'; 250 if (getnameinfo(r->ai_addr, r->ai_addrlen, 251 hbuf, (socklen_t)sizeof(hbuf), NULL, 0, niflags) != 252 0) 253 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 254 errno = oerrno; 255 warn("rcmd: connect to address %s", hbuf); 256 r = r->ai_next; 257 hbuf[0] = '\0'; 258 if (getnameinfo(r->ai_addr, r->ai_addrlen, 259 hbuf, (socklen_t)sizeof(hbuf), NULL, 0, niflags) != 260 0) 261 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 262 (void)fprintf(stderr, "Trying %s...\n", hbuf); 263 continue; 264 } 265 if (refused && timo <= 16) { 266 (void)sleep((unsigned int)timo); 267 timo *= 2; 268 r = res; 269 refused = 0; 270 continue; 271 } 272 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 273 strerror(errno)); 274 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 275 return -1; 276 } 277 lport--; 278 if (fd2p == 0) { 279 write(s, "", 1); 280 lport = 0; 281 } else { 282 char num[8]; 283 int s2 = rresvport_af(&lport, r->ai_family), s3; 284 socklen_t len = sizeof(from); 285 286 if (s2 < 0) 287 goto bad; 288 listen(s2, 1); 289 (void)snprintf(num, sizeof(num), "%d", lport); 290 if (write(s, num, strlen(num) + 1) != 291 (ssize_t) (strlen(num) + 1)) { 292 warn("rcmd: write (setting up stderr)"); 293 (void)close(s2); 294 goto bad; 295 } 296 reads[0].fd = s; 297 reads[0].events = POLLIN; 298 reads[1].fd = s2; 299 reads[1].events = POLLIN; 300 errno = 0; 301 pollr = poll(reads, 2, INFTIM); 302 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 303 if (errno != 0) 304 warn("poll: setting up stderr"); 305 else 306 warnx( 307 "poll: protocol failure in circuit setup"); 308 (void)close(s2); 309 goto bad; 310 } 311 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 312 (void)close(s2); 313 if (s3 < 0) { 314 warn("rcmd: accept"); 315 lport = 0; 316 goto bad; 317 } 318 *fd2p = s3; 319 switch (((struct sockaddr *)(void *)&from)->sa_family) { 320 case AF_INET: 321 #ifdef INET6 322 case AF_INET6: 323 #endif 324 if (getnameinfo((struct sockaddr *)(void *)&from, len, 325 NULL, 0, num, (socklen_t)sizeof(num), 326 NI_NUMERICSERV) != 0 || 327 (atoi(num) >= IPPORT_RESERVED || 328 atoi(num) < IPPORT_RESERVED / 2)) { 329 warnx( 330 "rcmd: protocol failure in circuit setup."); 331 goto bad2; 332 } 333 break; 334 default: 335 break; 336 } 337 } 338 339 (void)write(s, locuser, strlen(locuser)+1); 340 (void)write(s, remuser, strlen(remuser)+1); 341 (void)write(s, cmd, strlen(cmd)+1); 342 if (read(s, &c, 1) != 1) { 343 warn("%s", *ahost); 344 goto bad2; 345 } 346 if (c != 0) { 347 while (read(s, &c, 1) == 1) { 348 (void)write(STDERR_FILENO, &c, 1); 349 if (c == '\n') 350 break; 351 } 352 goto bad2; 353 } 354 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 355 return s; 356 bad2: 357 if (lport) 358 (void)close(*fd2p); 359 bad: 360 (void)close(s); 361 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 362 return -1; 363 } 364 365 /* 366 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 367 */ 368 /* ARGSUSED */ 369 static int 370 rshrcmd(int af, char **ahost, u_int32_t rport, const char *locuser, 371 const char *remuser, const char *cmd, int *fd2p, const char *rshcmd) 372 { 373 pid_t pid; 374 int sp[2], ep[2]; 375 char *p; 376 struct passwd *pw, pwres; 377 char pwbuf[1024]; 378 379 _DIAGASSERT(ahost != NULL); 380 _DIAGASSERT(locuser != NULL); 381 _DIAGASSERT(remuser != NULL); 382 _DIAGASSERT(cmd != NULL); 383 /* fd2p may be NULL */ 384 385 /* What rsh/shell to use. */ 386 if (rshcmd == NULL) 387 rshcmd = _PATH_BIN_RCMD; 388 389 /* locuser must exist on this host. */ 390 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || 391 pw == NULL) { 392 warnx("%s: unknown user: %s", __func__, locuser); 393 return -1; 394 } 395 396 /* get a socketpair we'll use for stdin and stdout. */ 397 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 398 warn("%s: socketpair", __func__); 399 return -1; 400 } 401 /* we will use this for the fd2 pointer */ 402 if (fd2p) { 403 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 404 warn("%s: socketpair", __func__); 405 return -1; 406 } 407 *fd2p = ep[0]; 408 } 409 410 pid = fork(); 411 if (pid < 0) { 412 warn("%s: fork", __func__); 413 return -1; 414 } 415 if (pid == 0) { 416 /* 417 * child 418 * - we use sp[1] to be stdin/stdout, and close sp[0] 419 * - with fd2p, we use ep[1] for stderr, and close ep[0] 420 */ 421 (void)close(sp[0]); 422 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 423 warn("%s: dup2", __func__); 424 _exit(1); 425 } 426 (void)close(sp[1]); 427 if (fd2p) { 428 if (dup2(ep[1], 2) < 0) { 429 warn("%s: dup2", __func__); 430 _exit(1); 431 } 432 (void)close(ep[0]); 433 (void)close(ep[1]); 434 } else if (dup2(0, 2) < 0) { 435 warn("%s: dup2", __func__); 436 _exit(1); 437 } 438 /* fork again to lose parent. */ 439 pid = fork(); 440 if (pid < 0) { 441 warn("%s: second fork", __func__); 442 _exit(1); 443 } 444 if (pid > 0) 445 _exit(0); 446 447 /* Orphan. Become local user for rshprog. */ 448 if (setuid(pw->pw_uid)) { 449 warn("%s: setuid(%lu)", __func__, (u_long)pw->pw_uid); 450 _exit(1); 451 } 452 453 /* 454 * If we are rcmd'ing to "localhost" as the same user as we 455 * are, then avoid running remote shell for efficiency. 456 */ 457 if (strcmp(*ahost, "localhost") == 0 && 458 strcmp(locuser, remuser) == 0) { 459 if (pw->pw_shell[0] == '\0') 460 rshcmd = _PATH_BSHELL; 461 else 462 rshcmd = pw->pw_shell; 463 p = strrchr(rshcmd, '/'); 464 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 465 } else { 466 const char *program; 467 program = strrchr(rshcmd, '/'); 468 program = program ? program + 1 : rshcmd; 469 if (fd2p) 470 /* ask rcmd to relay signal information */ 471 setenv("RCMD_RELAY_SIGNAL", "YES", 1); 472 switch (af) { 473 case AF_INET: 474 execlp(rshcmd, program, "-4", "-l", remuser, 475 *ahost, cmd, NULL); 476 break; 477 478 case AF_INET6: 479 execlp(rshcmd, program, "-6", "-l", remuser, 480 *ahost, cmd, NULL); 481 break; 482 483 default: 484 /* typically AF_UNSPEC, plus whatever */ 485 execlp(rshcmd, program, "-l", remuser, 486 *ahost, cmd, NULL); 487 break; 488 } 489 } 490 warn("%s: exec %s", __func__, rshcmd); 491 _exit(1); 492 } 493 /* Parent */ 494 (void)close(sp[1]); 495 if (fd2p) 496 (void)close(ep[1]); 497 498 (void)waitpid(pid, NULL, 0); 499 return sp[0]; 500 } 501 502 int 503 rresvport(int *alport) 504 { 505 506 _DIAGASSERT(alport != NULL); 507 508 return rresvport_af(alport, AF_INET); 509 } 510 511 int 512 rresvport_af(int *alport, int family) 513 { 514 return rresvport_af_addr(alport, family, NULL); 515 } 516 517 int 518 rresvport_af_addr(int *alport, int family, void *addr) 519 { 520 struct sockaddr_storage ss; 521 struct sockaddr *sa; 522 socklen_t salen; 523 int s; 524 u_int16_t *portp; 525 526 _DIAGASSERT(alport != NULL); 527 528 memset(&ss, 0, sizeof(ss)); 529 sa = (struct sockaddr *)(void *)&ss; 530 switch (family) { 531 case AF_INET: 532 #ifdef BSD4_4 533 sa->sa_len = 534 #endif 535 salen = sizeof(struct sockaddr_in); 536 if (addr) 537 ((struct sockaddr_in *)(void *)sa)->sin_addr = 538 ((struct sockaddr_in *)addr)->sin_addr; 539 portp = &((struct sockaddr_in *)(void *)sa)->sin_port; 540 break; 541 #ifdef INET6 542 case AF_INET6: 543 #ifdef BSD4_4 544 sa->sa_len = 545 #endif 546 salen = sizeof(struct sockaddr_in6); 547 if (addr) 548 ((struct sockaddr_in6 *)(void *)sa)->sin6_addr = 549 ((struct sockaddr_in6 *)addr)->sin6_addr; 550 portp = &((struct sockaddr_in6 *)(void *)sa)->sin6_port; 551 break; 552 #endif 553 default: 554 errno = EAFNOSUPPORT; 555 return -1; 556 } 557 sa->sa_family = family; 558 s = socket(family, SOCK_STREAM, 0); 559 if (s < 0) 560 return -1; 561 #if defined(BSD4_4) && !defined(__minix) 562 switch (family) { 563 case AF_INET: 564 case AF_INET6: 565 *portp = 0; 566 if (bindresvport(s, (struct sockaddr_in *)(void *)sa) < 0) { 567 int sverr = errno; 568 569 (void)close(s); 570 errno = sverr; 571 return -1; 572 } 573 *alport = (int)ntohs(*portp); 574 return s; 575 default: 576 /* is it necessary to try keep code for other AFs? */ 577 break; 578 } 579 #endif 580 for (;;) { 581 *portp = htons((u_short)*alport); 582 if (bind(s, sa, salen) >= 0) 583 return s; 584 if (errno != EADDRINUSE) { 585 (void)close(s); 586 return -1; 587 } 588 (*alport)--; 589 if (*alport == IPPORT_RESERVED/2) { 590 (void)close(s); 591 errno = EAGAIN; /* close */ 592 return -1; 593 } 594 } 595 } 596 597 int __check_rhosts_file = 1; 598 const char *__rcmd_errstr; 599 600 int 601 ruserok(const char *rhost, int superuser, const char *ruser, const char *luser) 602 { 603 struct addrinfo hints, *res, *r; 604 int error; 605 606 _DIAGASSERT(rhost != NULL); 607 _DIAGASSERT(ruser != NULL); 608 _DIAGASSERT(luser != NULL); 609 610 memset(&hints, 0, sizeof(hints)); 611 hints.ai_family = PF_UNSPEC; 612 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 613 error = getaddrinfo(rhost, "0", &hints, &res); 614 if (error) 615 return -1; 616 617 for (r = res; r; r = r->ai_next) { 618 if (iruserok_sa(r->ai_addr, (int)r->ai_addrlen, superuser, 619 ruser, luser) == 0) { 620 freeaddrinfo(res); 621 return 0; 622 } 623 } 624 freeaddrinfo(res); 625 return -1; 626 } 627 628 /* 629 * New .rhosts strategy: We are passed an ip address. We spin through 630 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 631 * has ip addresses, we don't have to trust a nameserver. When it 632 * contains hostnames, we spin through the list of addresses the nameserver 633 * gives us and look for a match. 634 * 635 * Returns 0 if ok, -1 if not ok. 636 */ 637 int 638 iruserok(u_int32_t raddr, int superuser, const char *ruser, const char *luser) 639 { 640 struct sockaddr_in irsin; 641 642 memset(&irsin, 0, sizeof(irsin)); 643 irsin.sin_family = AF_INET; 644 #ifdef BSD4_4 645 irsin.sin_len = sizeof(irsin); 646 #endif 647 memcpy(&irsin.sin_addr, &raddr, sizeof(irsin.sin_addr)); 648 return iruserok_sa(&irsin, (socklen_t)sizeof(irsin), superuser, ruser, 649 luser); 650 } 651 652 /* 653 * 2nd and 3rd arguments are typed like this, to avoid dependency between 654 * unistd.h and sys/socket.h. There's no better way. 655 */ 656 int 657 iruserok_sa(const void *raddr, int rlen, int superuser, const char *ruser, 658 const char *luser) 659 { 660 const struct sockaddr *sa; 661 struct stat sbuf; 662 struct passwd *pwd, pwres; 663 FILE *hostf; 664 uid_t uid; 665 gid_t gid; 666 int isvaliduser; 667 char pbuf[MAXPATHLEN]; 668 char pwbuf[1024]; 669 670 _DIAGASSERT(raddr != NULL); 671 _DIAGASSERT(ruser != NULL); 672 _DIAGASSERT(luser != NULL); 673 674 sa = raddr; 675 676 __rcmd_errstr = NULL; 677 678 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "re"); 679 680 if (hostf) { 681 if (__ivaliduser_sa(hostf, sa, (socklen_t)rlen, luser, 682 ruser) == 0) { 683 (void)fclose(hostf); 684 return 0; 685 } 686 (void)fclose(hostf); 687 } 688 689 isvaliduser = -1; 690 if (__check_rhosts_file || superuser) { 691 692 if (getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 693 || pwd == NULL) 694 return -1; 695 (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf)); 696 (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf)); 697 698 /* 699 * Change effective uid while opening and reading .rhosts. 700 * If root and reading an NFS mounted file system, can't 701 * read files that are protected read/write owner only. 702 */ 703 uid = geteuid(); 704 gid = getegid(); 705 (void)setegid(pwd->pw_gid); 706 (void)initgroups(pwd->pw_name, pwd->pw_gid); 707 (void)seteuid(pwd->pw_uid); 708 hostf = fopen(pbuf, "re"); 709 710 if (hostf != NULL) { 711 /* 712 * If not a regular file, or is owned by someone other 713 * than user or root or if writable by anyone but the 714 * owner, quit. 715 */ 716 if (lstat(pbuf, &sbuf) < 0) 717 __rcmd_errstr = ".rhosts lstat failed"; 718 else if (!S_ISREG(sbuf.st_mode)) 719 __rcmd_errstr = ".rhosts not regular file"; 720 else if (fstat(fileno(hostf), &sbuf) < 0) 721 __rcmd_errstr = ".rhosts fstat failed"; 722 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 723 __rcmd_errstr = "bad .rhosts owner"; 724 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 725 __rcmd_errstr = 726 ".rhosts writable by other than owner"; 727 else 728 isvaliduser = 729 __ivaliduser_sa(hostf, sa, (socklen_t)rlen, 730 luser, ruser); 731 732 (void)fclose(hostf); 733 } 734 (void)seteuid(uid); 735 (void)setegid(gid); 736 737 } 738 return isvaliduser; 739 } 740 741 /* 742 * XXX 743 * Don't make static, used by lpd(8). We will be able to change the function 744 * into static function, when we bump libc major #. 745 * 746 * Returns 0 if ok, -1 if not ok. 747 */ 748 #ifdef notdef /*_LIBC*/ 749 static 750 #endif 751 int 752 __ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, 753 const char *ruser) 754 { 755 struct sockaddr_in ivusin; 756 757 memset(&ivusin, 0, sizeof(ivusin)); 758 ivusin.sin_family = AF_INET; 759 #ifdef BSD4_4 760 ivusin.sin_len = sizeof(ivusin); 761 #endif 762 memcpy(&ivusin.sin_addr, &raddr, sizeof(ivusin.sin_addr)); 763 return __ivaliduser_sa(hostf, (struct sockaddr *)(void *)&ivusin, 764 (socklen_t)sizeof(ivusin), luser, ruser); 765 } 766 767 #ifdef notdef /*_LIBC*/ 768 static 769 #endif 770 int 771 __ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen, 772 const char *luser, const char *ruser) 773 { 774 char *user, *p; 775 int ch; 776 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 777 const char *auser, *ahost; 778 int hostok, userok; 779 char *rhost = NULL; 780 int firsttime = 1; 781 char domain[MAXHOSTNAMELEN]; 782 783 getdomainname(domain, sizeof(domain)); 784 785 _DIAGASSERT(hostf != NULL); 786 _DIAGASSERT(luser != NULL); 787 _DIAGASSERT(ruser != NULL); 788 789 while (fgets(buf, (int)sizeof(buf), hostf)) { 790 p = buf; 791 /* Skip lines that are too long. */ 792 if (strchr(p, '\n') == NULL) { 793 while ((ch = getc(hostf)) != '\n' && ch != EOF) 794 ; 795 continue; 796 } 797 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 798 *p = isupper((unsigned char)*p) ? 799 tolower((unsigned char)*p) : *p; 800 p++; 801 } 802 if (*p == ' ' || *p == '\t') { 803 *p++ = '\0'; 804 while (*p == ' ' || *p == '\t') 805 p++; 806 user = p; 807 while (*p != '\n' && *p != ' ' && 808 *p != '\t' && *p != '\0') 809 p++; 810 } else 811 user = p; 812 *p = '\0'; 813 814 if (p == buf) 815 continue; 816 817 auser = *user ? user : luser; 818 ahost = buf; 819 820 if (ahost[0] == '+') 821 switch (ahost[1]) { 822 case '\0': 823 hostok = 1; 824 break; 825 826 case '@': 827 if (firsttime) { 828 rhost = __gethostloop(raddr, salen); 829 firsttime = 0; 830 } 831 if (rhost) 832 hostok = innetgr(&ahost[2], rhost, 833 NULL, domain); 834 else 835 hostok = 0; 836 break; 837 838 default: 839 hostok = __icheckhost(raddr, salen, &ahost[1]); 840 break; 841 } 842 else if (ahost[0] == '-') 843 switch (ahost[1]) { 844 case '\0': 845 hostok = -1; 846 break; 847 848 case '@': 849 if (firsttime) { 850 rhost = __gethostloop(raddr, salen); 851 firsttime = 0; 852 } 853 if (rhost) 854 hostok = -innetgr(&ahost[2], rhost, 855 NULL, domain); 856 else 857 hostok = 0; 858 break; 859 860 default: 861 hostok = 862 -__icheckhost(raddr, salen, &ahost[1]); 863 break; 864 } 865 else 866 hostok = __icheckhost(raddr, salen, ahost); 867 868 869 if (auser[0] == '+') 870 switch (auser[1]) { 871 case '\0': 872 userok = 1; 873 break; 874 875 case '@': 876 userok = innetgr(&auser[2], NULL, ruser, 877 domain); 878 break; 879 880 default: 881 userok = strcmp(ruser, &auser[1]) == 0; 882 break; 883 } 884 else if (auser[0] == '-') 885 switch (auser[1]) { 886 case '\0': 887 userok = -1; 888 break; 889 890 case '@': 891 userok = -innetgr(&auser[2], NULL, ruser, 892 domain); 893 break; 894 895 default: 896 userok = 897 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 898 break; 899 } 900 else 901 userok = strcmp(ruser, auser) == 0; 902 903 /* Check if one component did not match */ 904 if (hostok == 0 || userok == 0) 905 continue; 906 907 /* Check if we got a forbidden pair */ 908 if (userok == -1 || hostok == -1) 909 return -1; 910 911 /* Check if we got a valid pair */ 912 if (hostok == 1 && userok == 1) 913 return 0; 914 } 915 return -1; 916 } 917 918 /* 919 * Returns "true" if match, 0 if no match. 920 */ 921 static int 922 __icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost) 923 { 924 struct addrinfo hints, *res, *r; 925 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 926 int error; 927 const int niflags = NI_NUMERICHOST; 928 929 _DIAGASSERT(raddr != NULL); 930 _DIAGASSERT(lhost != NULL); 931 932 h1[0] = '\0'; 933 if (getnameinfo(raddr, salen, h1, (socklen_t)sizeof(h1), NULL, 0, 934 niflags) != 0) 935 return 0; 936 937 /* Resolve laddr into sockaddr */ 938 memset(&hints, 0, sizeof(hints)); 939 hints.ai_family = raddr->sa_family; 940 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 941 res = NULL; 942 error = getaddrinfo(lhost, "0", &hints, &res); 943 if (error) 944 return 0; 945 946 /* 947 * Try string comparisons between raddr and laddr. 948 */ 949 for (r = res; r; r = r->ai_next) { 950 h2[0] = '\0'; 951 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, 952 (socklen_t)sizeof(h2), NULL, 0, niflags) != 0) 953 continue; 954 if (strcmp(h1, h2) == 0) { 955 freeaddrinfo(res); 956 return 1; 957 } 958 } 959 960 /* No match. */ 961 freeaddrinfo(res); 962 return 0; 963 } 964 965 /* 966 * Return the hostname associated with the supplied address. 967 * Do a reverse lookup as well for security. If a loop cannot 968 * be found, pack the numeric IP address into the string. 969 */ 970 static char * 971 __gethostloop(const struct sockaddr *raddr, socklen_t salen) 972 { 973 static char remotehost[NI_MAXHOST]; 974 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 975 struct addrinfo hints, *res, *r; 976 int error; 977 const int niflags = NI_NUMERICHOST; 978 979 _DIAGASSERT(raddr != NULL); 980 981 h1[0] = remotehost[0] = '\0'; 982 if (getnameinfo(raddr, salen, remotehost, (socklen_t)sizeof(remotehost), 983 NULL, 0, NI_NAMEREQD) != 0) 984 return NULL; 985 if (getnameinfo(raddr, salen, h1, (socklen_t)sizeof(h1), NULL, 0, 986 niflags) != 0) 987 return NULL; 988 989 /* 990 * Look up the name and check that the supplied 991 * address is in the list 992 */ 993 memset(&hints, 0, sizeof(hints)); 994 hints.ai_family = raddr->sa_family; 995 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 996 hints.ai_flags = AI_CANONNAME; 997 res = NULL; 998 error = getaddrinfo(remotehost, "0", &hints, &res); 999 if (error) 1000 return NULL; 1001 1002 for (r = res; r; r = r->ai_next) { 1003 h2[0] = '\0'; 1004 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, 1005 (socklen_t)sizeof(h2), NULL, 0, niflags) != 0) 1006 continue; 1007 if (strcmp(h1, h2) == 0) { 1008 freeaddrinfo(res); 1009 return remotehost; 1010 } 1011 } 1012 1013 /* 1014 * either the DNS adminstrator has made a configuration 1015 * mistake, or someone has attempted to spoof us 1016 */ 1017 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 1018 h1, res->ai_canonname ? res->ai_canonname : remotehost); 1019 freeaddrinfo(res); 1020 return NULL; 1021 } 1022