1 /* $NetBSD: rcmd.c,v 1.66 2011/05/31 06:49:26 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 1.66 2011/05/31 06:49:26 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, sizeof(hbuf), NULL, 0, niflags) != 0) 250 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 251 errno = oerrno; 252 warn("rcmd: connect to address %s", hbuf); 253 r = r->ai_next; 254 hbuf[0] = '\0'; 255 if (getnameinfo(r->ai_addr, r->ai_addrlen, 256 hbuf, sizeof(hbuf), NULL, 0, niflags) != 0) 257 strlcpy(hbuf, "(invalid)", sizeof(hbuf)); 258 (void)fprintf(stderr, "Trying %s...\n", hbuf); 259 continue; 260 } 261 if (refused && timo <= 16) { 262 (void)sleep((unsigned int)timo); 263 timo *= 2; 264 r = res; 265 refused = 0; 266 continue; 267 } 268 (void)fprintf(stderr, "%s: %s\n", res->ai_canonname, 269 strerror(errno)); 270 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 271 return -1; 272 } 273 lport--; 274 if (fd2p == 0) { 275 write(s, "", 1); 276 lport = 0; 277 } else { 278 char num[8]; 279 int s2 = rresvport_af(&lport, r->ai_family), s3; 280 socklen_t len = sizeof(from); 281 282 if (s2 < 0) 283 goto bad; 284 listen(s2, 1); 285 (void)snprintf(num, sizeof(num), "%d", lport); 286 if (write(s, num, strlen(num) + 1) != 287 (ssize_t) (strlen(num) + 1)) { 288 warn("rcmd: write (setting up stderr)"); 289 (void)close(s2); 290 goto bad; 291 } 292 reads[0].fd = s; 293 reads[0].events = POLLIN; 294 reads[1].fd = s2; 295 reads[1].events = POLLIN; 296 errno = 0; 297 pollr = poll(reads, 2, INFTIM); 298 if (pollr < 1 || (reads[1].revents & POLLIN) == 0) { 299 if (errno != 0) 300 warn("poll: setting up stderr"); 301 else 302 warnx( 303 "poll: protocol failure in circuit setup"); 304 (void)close(s2); 305 goto bad; 306 } 307 s3 = accept(s2, (struct sockaddr *)(void *)&from, &len); 308 (void)close(s2); 309 if (s3 < 0) { 310 warn("rcmd: accept"); 311 lport = 0; 312 goto bad; 313 } 314 *fd2p = s3; 315 switch (((struct sockaddr *)(void *)&from)->sa_family) { 316 case AF_INET: 317 #ifdef INET6 318 case AF_INET6: 319 #endif 320 if (getnameinfo((struct sockaddr *)(void *)&from, len, 321 NULL, 0, num, sizeof(num), NI_NUMERICSERV) != 0 || 322 (atoi(num) >= IPPORT_RESERVED || 323 atoi(num) < IPPORT_RESERVED / 2)) { 324 warnx( 325 "rcmd: protocol failure in circuit setup."); 326 goto bad2; 327 } 328 break; 329 default: 330 break; 331 } 332 } 333 334 (void)write(s, locuser, strlen(locuser)+1); 335 (void)write(s, remuser, strlen(remuser)+1); 336 (void)write(s, cmd, strlen(cmd)+1); 337 if (read(s, &c, 1) != 1) { 338 warn("%s", *ahost); 339 goto bad2; 340 } 341 if (c != 0) { 342 while (read(s, &c, 1) == 1) { 343 (void)write(STDERR_FILENO, &c, 1); 344 if (c == '\n') 345 break; 346 } 347 goto bad2; 348 } 349 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 350 return s; 351 bad2: 352 if (lport) 353 (void)close(*fd2p); 354 bad: 355 (void)close(s); 356 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 357 return -1; 358 } 359 360 /* 361 * based on code written by Chris Siebenmann <cks@utcc.utoronto.ca> 362 */ 363 /* ARGSUSED */ 364 static int 365 rshrcmd(int af, char **ahost, u_int32_t rport, const char *locuser, 366 const char *remuser, const char *cmd, int *fd2p, const char *rshcmd) 367 { 368 pid_t pid; 369 int sp[2], ep[2]; 370 char *p; 371 struct passwd *pw, pwres; 372 char pwbuf[1024]; 373 374 _DIAGASSERT(ahost != NULL); 375 _DIAGASSERT(locuser != NULL); 376 _DIAGASSERT(remuser != NULL); 377 _DIAGASSERT(cmd != NULL); 378 /* fd2p may be NULL */ 379 380 /* What rsh/shell to use. */ 381 if (rshcmd == NULL) 382 rshcmd = _PATH_BIN_RCMD; 383 384 /* locuser must exist on this host. */ 385 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pw) != 0 || 386 pw == NULL) { 387 warnx("%s: unknown user: %s", __func__, locuser); 388 return -1; 389 } 390 391 /* get a socketpair we'll use for stdin and stdout. */ 392 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sp) < 0) { 393 warn("%s: socketpair", __func__); 394 return -1; 395 } 396 /* we will use this for the fd2 pointer */ 397 if (fd2p) { 398 if (socketpair(AF_LOCAL, SOCK_STREAM, 0, ep) < 0) { 399 warn("%s: socketpair", __func__); 400 return -1; 401 } 402 *fd2p = ep[0]; 403 } 404 405 pid = fork(); 406 if (pid < 0) { 407 warn("%s: fork", __func__); 408 return -1; 409 } 410 if (pid == 0) { 411 /* 412 * child 413 * - we use sp[1] to be stdin/stdout, and close sp[0] 414 * - with fd2p, we use ep[1] for stderr, and close ep[0] 415 */ 416 (void)close(sp[0]); 417 if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) { 418 warn("%s: dup2", __func__); 419 _exit(1); 420 } 421 (void)close(sp[1]); 422 if (fd2p) { 423 if (dup2(ep[1], 2) < 0) { 424 warn("%s: dup2", __func__); 425 _exit(1); 426 } 427 (void)close(ep[0]); 428 (void)close(ep[1]); 429 } else if (dup2(0, 2) < 0) { 430 warn("%s: dup2", __func__); 431 _exit(1); 432 } 433 /* fork again to lose parent. */ 434 pid = fork(); 435 if (pid < 0) { 436 warn("%s: second fork", __func__); 437 _exit(1); 438 } 439 if (pid > 0) 440 _exit(0); 441 442 /* Orphan. Become local user for rshprog. */ 443 if (setuid(pw->pw_uid)) { 444 warn("%s: setuid(%lu)", __func__, (u_long)pw->pw_uid); 445 _exit(1); 446 } 447 448 /* 449 * If we are rcmd'ing to "localhost" as the same user as we 450 * are, then avoid running remote shell for efficiency. 451 */ 452 if (strcmp(*ahost, "localhost") == 0 && 453 strcmp(locuser, remuser) == 0) { 454 if (pw->pw_shell[0] == '\0') 455 rshcmd = _PATH_BSHELL; 456 else 457 rshcmd = pw->pw_shell; 458 p = strrchr(rshcmd, '/'); 459 execlp(rshcmd, p ? p + 1 : rshcmd, "-c", cmd, NULL); 460 } else { 461 const char *program; 462 program = strrchr(rshcmd, '/'); 463 program = program ? program + 1 : rshcmd; 464 switch (af) { 465 case AF_INET: 466 execlp(rshcmd, program, "-4", "-l", remuser, 467 *ahost, cmd, NULL); 468 break; 469 470 case AF_INET6: 471 execlp(rshcmd, program, "-6", "-l", remuser, 472 *ahost, cmd, NULL); 473 break; 474 475 default: 476 /* typically AF_UNSPEC, plus whatever */ 477 execlp(rshcmd, program, "-l", remuser, 478 *ahost, cmd, NULL); 479 break; 480 } 481 } 482 warn("%s: exec %s", __func__, rshcmd); 483 _exit(1); 484 } 485 /* Parent */ 486 (void)close(sp[1]); 487 if (fd2p) 488 (void)close(ep[1]); 489 490 (void)waitpid(pid, NULL, 0); 491 return sp[0]; 492 } 493 494 int 495 rresvport(int *alport) 496 { 497 498 _DIAGASSERT(alport != NULL); 499 500 return rresvport_af(alport, AF_INET); 501 } 502 503 int 504 rresvport_af(int *alport, int family) 505 { 506 struct sockaddr_storage ss; 507 struct sockaddr *sa; 508 socklen_t salen; 509 int s; 510 u_int16_t *portp; 511 512 _DIAGASSERT(alport != NULL); 513 514 memset(&ss, 0, sizeof(ss)); 515 sa = (struct sockaddr *)(void *)&ss; 516 switch (family) { 517 case AF_INET: 518 #ifdef BSD4_4 519 sa->sa_len = 520 #endif 521 salen = sizeof(struct sockaddr_in); 522 portp = &((struct sockaddr_in *)(void *)sa)->sin_port; 523 break; 524 #ifdef INET6 525 case AF_INET6: 526 #ifdef BSD4_4 527 sa->sa_len = 528 #endif 529 salen = sizeof(struct sockaddr_in6); 530 portp = &((struct sockaddr_in6 *)(void *)sa)->sin6_port; 531 break; 532 #endif 533 default: 534 errno = EAFNOSUPPORT; 535 return -1; 536 } 537 sa->sa_family = family; 538 s = socket(family, SOCK_STREAM, 0); 539 if (s < 0) 540 return -1; 541 #ifdef BSD4_4 542 switch (family) { 543 case AF_INET: 544 case AF_INET6: 545 *portp = 0; 546 if (bindresvport(s, (struct sockaddr_in *)(void *)sa) < 0) { 547 int sverr = errno; 548 549 (void)close(s); 550 errno = sverr; 551 return -1; 552 } 553 *alport = (int)ntohs(*portp); 554 return s; 555 default: 556 /* is it necessary to try keep code for other AFs? */ 557 break; 558 } 559 #endif 560 for (;;) { 561 *portp = htons((u_short)*alport); 562 if (bind(s, sa, salen) >= 0) 563 return s; 564 if (errno != EADDRINUSE) { 565 (void)close(s); 566 return -1; 567 } 568 (*alport)--; 569 if (*alport == IPPORT_RESERVED/2) { 570 (void)close(s); 571 errno = EAGAIN; /* close */ 572 return -1; 573 } 574 } 575 } 576 577 int __check_rhosts_file = 1; 578 const char *__rcmd_errstr; 579 580 int 581 ruserok(const char *rhost, int superuser, const char *ruser, const char *luser) 582 { 583 struct addrinfo hints, *res, *r; 584 int error; 585 586 _DIAGASSERT(rhost != NULL); 587 _DIAGASSERT(ruser != NULL); 588 _DIAGASSERT(luser != NULL); 589 590 memset(&hints, 0, sizeof(hints)); 591 hints.ai_family = PF_UNSPEC; 592 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 593 error = getaddrinfo(rhost, "0", &hints, &res); 594 if (error) 595 return -1; 596 597 for (r = res; r; r = r->ai_next) { 598 if (iruserok_sa(r->ai_addr, (int)r->ai_addrlen, superuser, 599 ruser, luser) == 0) { 600 freeaddrinfo(res); 601 return 0; 602 } 603 } 604 freeaddrinfo(res); 605 return -1; 606 } 607 608 /* 609 * New .rhosts strategy: We are passed an ip address. We spin through 610 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 611 * has ip addresses, we don't have to trust a nameserver. When it 612 * contains hostnames, we spin through the list of addresses the nameserver 613 * gives us and look for a match. 614 * 615 * Returns 0 if ok, -1 if not ok. 616 */ 617 int 618 iruserok(u_int32_t raddr, int superuser, const char *ruser, const char *luser) 619 { 620 struct sockaddr_in irsin; 621 622 memset(&irsin, 0, sizeof(irsin)); 623 irsin.sin_family = AF_INET; 624 #ifdef BSD4_4 625 irsin.sin_len = sizeof(irsin); 626 #endif 627 memcpy(&irsin.sin_addr, &raddr, sizeof(irsin.sin_addr)); 628 return iruserok_sa(&irsin, sizeof(irsin), superuser, ruser, luser); 629 } 630 631 /* 632 * 2nd and 3rd arguments are typed like this, to avoid dependency between 633 * unistd.h and sys/socket.h. There's no better way. 634 */ 635 int 636 iruserok_sa(const void *raddr, int rlen, int superuser, const char *ruser, 637 const char *luser) 638 { 639 const struct sockaddr *sa; 640 struct stat sbuf; 641 struct passwd *pwd, pwres; 642 FILE *hostf; 643 uid_t uid; 644 gid_t gid; 645 int isvaliduser; 646 char pbuf[MAXPATHLEN]; 647 char pwbuf[1024]; 648 649 _DIAGASSERT(raddr != NULL); 650 _DIAGASSERT(ruser != NULL); 651 _DIAGASSERT(luser != NULL); 652 653 sa = raddr; 654 655 __rcmd_errstr = NULL; 656 657 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 658 659 if (hostf) { 660 if (__ivaliduser_sa(hostf, sa, (socklen_t)rlen, luser, 661 ruser) == 0) { 662 (void)fclose(hostf); 663 return 0; 664 } 665 (void)fclose(hostf); 666 } 667 668 isvaliduser = -1; 669 if (__check_rhosts_file || superuser) { 670 671 if (getpwnam_r(luser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 672 || pwd == NULL) 673 return -1; 674 (void)strlcpy(pbuf, pwd->pw_dir, sizeof(pbuf)); 675 (void)strlcat(pbuf, "/.rhosts", sizeof(pbuf)); 676 677 /* 678 * Change effective uid while opening and reading .rhosts. 679 * If root and reading an NFS mounted file system, can't 680 * read files that are protected read/write owner only. 681 */ 682 uid = geteuid(); 683 gid = getegid(); 684 (void)setegid(pwd->pw_gid); 685 initgroups(pwd->pw_name, pwd->pw_gid); 686 (void)seteuid(pwd->pw_uid); 687 hostf = fopen(pbuf, "r"); 688 689 if (hostf != NULL) { 690 /* 691 * If not a regular file, or is owned by someone other 692 * than user or root or if writable by anyone but the 693 * owner, quit. 694 */ 695 if (lstat(pbuf, &sbuf) < 0) 696 __rcmd_errstr = ".rhosts lstat failed"; 697 else if (!S_ISREG(sbuf.st_mode)) 698 __rcmd_errstr = ".rhosts not regular file"; 699 else if (fstat(fileno(hostf), &sbuf) < 0) 700 __rcmd_errstr = ".rhosts fstat failed"; 701 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 702 __rcmd_errstr = "bad .rhosts owner"; 703 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 704 __rcmd_errstr = 705 ".rhosts writable by other than owner"; 706 else 707 isvaliduser = 708 __ivaliduser_sa(hostf, sa, (socklen_t)rlen, 709 luser, ruser); 710 711 (void)fclose(hostf); 712 } 713 (void)seteuid(uid); 714 (void)setegid(gid); 715 716 } 717 return isvaliduser; 718 } 719 720 /* 721 * XXX 722 * Don't make static, used by lpd(8). We will be able to change the function 723 * into static function, when we bump libc major #. 724 * 725 * Returns 0 if ok, -1 if not ok. 726 */ 727 #ifdef notdef /*_LIBC*/ 728 static 729 #endif 730 int 731 __ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, 732 const char *ruser) 733 { 734 struct sockaddr_in ivusin; 735 736 memset(&ivusin, 0, sizeof(ivusin)); 737 ivusin.sin_family = AF_INET; 738 #ifdef BSD4_4 739 ivusin.sin_len = sizeof(ivusin); 740 #endif 741 memcpy(&ivusin.sin_addr, &raddr, sizeof(ivusin.sin_addr)); 742 return __ivaliduser_sa(hostf, (struct sockaddr *)(void *)&ivusin, 743 sizeof(ivusin), luser, ruser); 744 } 745 746 #ifdef notdef /*_LIBC*/ 747 static 748 #endif 749 int 750 __ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen, 751 const char *luser, const char *ruser) 752 { 753 char *user, *p; 754 int ch; 755 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 756 const char *auser, *ahost; 757 int hostok, userok; 758 char *rhost = NULL; 759 int firsttime = 1; 760 char domain[MAXHOSTNAMELEN]; 761 762 getdomainname(domain, sizeof(domain)); 763 764 _DIAGASSERT(hostf != NULL); 765 _DIAGASSERT(luser != NULL); 766 _DIAGASSERT(ruser != NULL); 767 768 while (fgets(buf, sizeof(buf), hostf)) { 769 p = buf; 770 /* Skip lines that are too long. */ 771 if (strchr(p, '\n') == NULL) { 772 while ((ch = getc(hostf)) != '\n' && ch != EOF) 773 ; 774 continue; 775 } 776 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 777 *p = isupper((unsigned char)*p) ? 778 tolower((unsigned char)*p) : *p; 779 p++; 780 } 781 if (*p == ' ' || *p == '\t') { 782 *p++ = '\0'; 783 while (*p == ' ' || *p == '\t') 784 p++; 785 user = p; 786 while (*p != '\n' && *p != ' ' && 787 *p != '\t' && *p != '\0') 788 p++; 789 } else 790 user = p; 791 *p = '\0'; 792 793 if (p == buf) 794 continue; 795 796 auser = *user ? user : luser; 797 ahost = buf; 798 799 if (ahost[0] == '+') 800 switch (ahost[1]) { 801 case '\0': 802 hostok = 1; 803 break; 804 805 case '@': 806 if (firsttime) { 807 rhost = __gethostloop(raddr, salen); 808 firsttime = 0; 809 } 810 if (rhost) 811 hostok = innetgr(&ahost[2], rhost, 812 NULL, domain); 813 else 814 hostok = 0; 815 break; 816 817 default: 818 hostok = __icheckhost(raddr, salen, &ahost[1]); 819 break; 820 } 821 else if (ahost[0] == '-') 822 switch (ahost[1]) { 823 case '\0': 824 hostok = -1; 825 break; 826 827 case '@': 828 if (firsttime) { 829 rhost = __gethostloop(raddr, salen); 830 firsttime = 0; 831 } 832 if (rhost) 833 hostok = -innetgr(&ahost[2], rhost, 834 NULL, domain); 835 else 836 hostok = 0; 837 break; 838 839 default: 840 hostok = 841 -__icheckhost(raddr, salen, &ahost[1]); 842 break; 843 } 844 else 845 hostok = __icheckhost(raddr, salen, ahost); 846 847 848 if (auser[0] == '+') 849 switch (auser[1]) { 850 case '\0': 851 userok = 1; 852 break; 853 854 case '@': 855 userok = innetgr(&auser[2], NULL, ruser, 856 domain); 857 break; 858 859 default: 860 userok = strcmp(ruser, &auser[1]) == 0; 861 break; 862 } 863 else if (auser[0] == '-') 864 switch (auser[1]) { 865 case '\0': 866 userok = -1; 867 break; 868 869 case '@': 870 userok = -innetgr(&auser[2], NULL, ruser, 871 domain); 872 break; 873 874 default: 875 userok = 876 -(strcmp(ruser, &auser[1]) == 0 ? 1 : 0); 877 break; 878 } 879 else 880 userok = strcmp(ruser, auser) == 0; 881 882 /* Check if one component did not match */ 883 if (hostok == 0 || userok == 0) 884 continue; 885 886 /* Check if we got a forbidden pair */ 887 if (userok == -1 || hostok == -1) 888 return -1; 889 890 /* Check if we got a valid pair */ 891 if (hostok == 1 && userok == 1) 892 return 0; 893 } 894 return -1; 895 } 896 897 /* 898 * Returns "true" if match, 0 if no match. 899 */ 900 static int 901 __icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost) 902 { 903 struct addrinfo hints, *res, *r; 904 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 905 int error; 906 const int niflags = NI_NUMERICHOST; 907 908 _DIAGASSERT(raddr != NULL); 909 _DIAGASSERT(lhost != NULL); 910 911 h1[0] = '\0'; 912 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, niflags) != 0) 913 return 0; 914 915 /* Resolve laddr into sockaddr */ 916 memset(&hints, 0, sizeof(hints)); 917 hints.ai_family = raddr->sa_family; 918 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 919 res = NULL; 920 error = getaddrinfo(lhost, "0", &hints, &res); 921 if (error) 922 return 0; 923 924 /* 925 * Try string comparisons between raddr and laddr. 926 */ 927 for (r = res; r; r = r->ai_next) { 928 h2[0] = '\0'; 929 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 930 NULL, 0, niflags) != 0) 931 continue; 932 if (strcmp(h1, h2) == 0) { 933 freeaddrinfo(res); 934 return 1; 935 } 936 } 937 938 /* No match. */ 939 freeaddrinfo(res); 940 return 0; 941 } 942 943 /* 944 * Return the hostname associated with the supplied address. 945 * Do a reverse lookup as well for security. If a loop cannot 946 * be found, pack the numeric IP address into the string. 947 */ 948 static char * 949 __gethostloop(const struct sockaddr *raddr, socklen_t salen) 950 { 951 static char remotehost[NI_MAXHOST]; 952 char h1[NI_MAXHOST], h2[NI_MAXHOST]; 953 struct addrinfo hints, *res, *r; 954 int error; 955 const int niflags = NI_NUMERICHOST; 956 957 _DIAGASSERT(raddr != NULL); 958 959 h1[0] = remotehost[0] = '\0'; 960 if (getnameinfo(raddr, salen, remotehost, sizeof(remotehost), 961 NULL, 0, NI_NAMEREQD) != 0) 962 return NULL; 963 if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0, niflags) != 0) 964 return NULL; 965 966 /* 967 * Look up the name and check that the supplied 968 * address is in the list 969 */ 970 memset(&hints, 0, sizeof(hints)); 971 hints.ai_family = raddr->sa_family; 972 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 973 hints.ai_flags = AI_CANONNAME; 974 res = NULL; 975 error = getaddrinfo(remotehost, "0", &hints, &res); 976 if (error) 977 return NULL; 978 979 for (r = res; r; r = r->ai_next) { 980 h2[0] = '\0'; 981 if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2), 982 NULL, 0, niflags) != 0) 983 continue; 984 if (strcmp(h1, h2) == 0) { 985 freeaddrinfo(res); 986 return remotehost; 987 } 988 } 989 990 /* 991 * either the DNS adminstrator has made a configuration 992 * mistake, or someone has attempted to spoof us 993 */ 994 syslog(LOG_NOTICE, "rcmd: address %s not listed for host %s", 995 h1, res->ai_canonname ? res->ai_canonname : remotehost); 996 freeaddrinfo(res); 997 return NULL; 998 } 999