1 /* $NetBSD: rcmd.c,v 1.12 1995/06/03 22:33:34 mycroft 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 39 #else 40 static char *rcsid = "$NetBSD: rcmd.c,v 1.12 1995/06/03 22:33:34 mycroft Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <sys/param.h> 45 #include <sys/socket.h> 46 #include <sys/stat.h> 47 48 #include <netinet/in.h> 49 #include <arpa/inet.h> 50 51 #include <signal.h> 52 #include <fcntl.h> 53 #include <netdb.h> 54 #include <unistd.h> 55 #include <pwd.h> 56 #include <errno.h> 57 #include <stdio.h> 58 #include <ctype.h> 59 #include <string.h> 60 61 int __ivaliduser __P((FILE *, u_long, const char *, const char *)); 62 static int __icheckhost __P((u_long, const char *)); 63 64 int 65 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 66 char **ahost; 67 u_short rport; 68 const char *locuser, *remuser, *cmd; 69 int *fd2p; 70 { 71 struct hostent *hp; 72 struct sockaddr_in sin, from; 73 fd_set reads; 74 long oldmask; 75 pid_t pid; 76 int s, lport, timo; 77 char c; 78 79 pid = getpid(); 80 hp = gethostbyname(*ahost); 81 if (hp == NULL) { 82 herror(*ahost); 83 return (-1); 84 } 85 *ahost = hp->h_name; 86 oldmask = sigblock(sigmask(SIGURG)); 87 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 88 s = rresvport(&lport); 89 if (s < 0) { 90 if (errno == EAGAIN) 91 (void)fprintf(stderr, 92 "rcmd: socket: All ports in use\n"); 93 else 94 (void)fprintf(stderr, "rcmd: socket: %s\n", 95 strerror(errno)); 96 sigsetmask(oldmask); 97 return (-1); 98 } 99 fcntl(s, F_SETOWN, pid); 100 sin.sin_len = sizeof(struct sockaddr_in); 101 sin.sin_family = hp->h_addrtype; 102 sin.sin_port = rport; 103 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); 104 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 105 break; 106 (void)close(s); 107 if (errno == EADDRINUSE) { 108 lport--; 109 continue; 110 } 111 if (errno == ECONNREFUSED && timo <= 16) { 112 (void)sleep(timo); 113 timo *= 2; 114 continue; 115 } 116 if (hp->h_addr_list[1] != NULL) { 117 int oerrno = errno; 118 119 (void)fprintf(stderr, "connect to address %s: ", 120 inet_ntoa(sin.sin_addr)); 121 errno = oerrno; 122 perror(0); 123 hp->h_addr_list++; 124 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); 125 (void)fprintf(stderr, "Trying %s...\n", 126 inet_ntoa(sin.sin_addr)); 127 continue; 128 } 129 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno)); 130 sigsetmask(oldmask); 131 return (-1); 132 } 133 lport--; 134 if (fd2p == 0) { 135 write(s, "", 1); 136 lport = 0; 137 } else { 138 char num[8]; 139 int s2 = rresvport(&lport), s3; 140 int len = sizeof(from); 141 142 if (s2 < 0) 143 goto bad; 144 listen(s2, 1); 145 (void)snprintf(num, sizeof(num), "%d", lport); 146 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 147 (void)fprintf(stderr, 148 "rcmd: write (setting up stderr): %s\n", 149 strerror(errno)); 150 (void)close(s2); 151 goto bad; 152 } 153 FD_ZERO(&reads); 154 FD_SET(s, &reads); 155 FD_SET(s2, &reads); 156 errno = 0; 157 if (select(MAX(s, s2) + 1, &reads, 0, 0, 0) < 1 || 158 !FD_ISSET(s2, &reads)) { 159 if (errno != 0) 160 (void)fprintf(stderr, 161 "rcmd: select (setting up stderr): %s\n", 162 strerror(errno)); 163 else 164 (void)fprintf(stderr, 165 "select: protocol failure in circuit setup\n"); 166 (void)close(s2); 167 goto bad; 168 } 169 s3 = accept(s2, (struct sockaddr *)&from, &len); 170 (void)close(s2); 171 if (s3 < 0) { 172 (void)fprintf(stderr, 173 "rcmd: accept: %s\n", strerror(errno)); 174 lport = 0; 175 goto bad; 176 } 177 *fd2p = s3; 178 from.sin_port = ntohs(from.sin_port); 179 if (from.sin_family != AF_INET || 180 from.sin_port >= IPPORT_RESERVED || 181 from.sin_port < IPPORT_RESERVED / 2) { 182 (void)fprintf(stderr, 183 "socket: protocol failure in circuit setup.\n"); 184 goto bad2; 185 } 186 } 187 (void)write(s, locuser, strlen(locuser)+1); 188 (void)write(s, remuser, strlen(remuser)+1); 189 (void)write(s, cmd, strlen(cmd)+1); 190 if (read(s, &c, 1) != 1) { 191 (void)fprintf(stderr, 192 "rcmd: %s: %s\n", *ahost, strerror(errno)); 193 goto bad2; 194 } 195 if (c != 0) { 196 while (read(s, &c, 1) == 1) { 197 (void)write(STDERR_FILENO, &c, 1); 198 if (c == '\n') 199 break; 200 } 201 goto bad2; 202 } 203 sigsetmask(oldmask); 204 return (s); 205 bad2: 206 if (lport) 207 (void)close(*fd2p); 208 bad: 209 (void)close(s); 210 sigsetmask(oldmask); 211 return (-1); 212 } 213 214 int 215 rresvport(alport) 216 int *alport; 217 { 218 struct sockaddr_in sin; 219 int s; 220 221 sin.sin_len = sizeof(struct sockaddr_in); 222 sin.sin_family = AF_INET; 223 sin.sin_addr.s_addr = INADDR_ANY; 224 s = socket(AF_INET, SOCK_STREAM, 0); 225 if (s < 0) 226 return (-1); 227 for (;;) { 228 sin.sin_port = htons((u_short)*alport); 229 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 230 return (s); 231 if (errno != EADDRINUSE) { 232 (void)close(s); 233 return (-1); 234 } 235 (*alport)--; 236 if (*alport == IPPORT_RESERVED/2) { 237 (void)close(s); 238 errno = EAGAIN; /* close */ 239 return (-1); 240 } 241 } 242 } 243 244 int __check_rhosts_file = 1; 245 char *__rcmd_errstr; 246 247 int 248 ruserok(rhost, superuser, ruser, luser) 249 const char *rhost, *ruser, *luser; 250 int superuser; 251 { 252 struct hostent *hp; 253 char **ap; 254 int i; 255 #define MAXADDRS 35 256 u_long addrs[MAXADDRS + 1]; 257 258 if ((hp = gethostbyname(rhost)) == NULL) 259 return (-1); 260 for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i) 261 bcopy(*ap, &addrs[i], sizeof(addrs[i])); 262 addrs[i] = 0; 263 264 for (i = 0; i < MAXADDRS && addrs[i]; i++) 265 if (iruserok(addrs[i], superuser, ruser, luser) == 0) 266 return (0); 267 return (-1); 268 } 269 270 /* 271 * New .rhosts strategy: We are passed an ip address. We spin through 272 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 273 * has ip addresses, we don't have to trust a nameserver. When it 274 * contains hostnames, we spin through the list of addresses the nameserver 275 * gives us and look for a match. 276 * 277 * Returns 0 if ok, -1 if not ok. 278 */ 279 int 280 iruserok(raddr, superuser, ruser, luser) 281 u_long raddr; 282 int superuser; 283 const char *ruser, *luser; 284 { 285 register char *cp; 286 struct stat sbuf; 287 struct passwd *pwd; 288 FILE *hostf; 289 uid_t uid; 290 int first; 291 char pbuf[MAXPATHLEN]; 292 293 first = 1; 294 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 295 again: 296 if (hostf) { 297 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) { 298 (void)fclose(hostf); 299 return (0); 300 } 301 (void)fclose(hostf); 302 } 303 if (first == 1 && (__check_rhosts_file || superuser)) { 304 first = 0; 305 if ((pwd = getpwnam(luser)) == NULL) 306 return (-1); 307 (void)strcpy(pbuf, pwd->pw_dir); 308 (void)strcat(pbuf, "/.rhosts"); 309 310 /* 311 * Change effective uid while opening .rhosts. If root and 312 * reading an NFS mounted file system, can't read files that 313 * are protected read/write owner only. 314 */ 315 uid = geteuid(); 316 (void)seteuid(pwd->pw_uid); 317 hostf = fopen(pbuf, "r"); 318 (void)seteuid(uid); 319 320 if (hostf == NULL) 321 return (-1); 322 /* 323 * If not a regular file, or is owned by someone other than 324 * user or root or if writeable by anyone but the owner, quit. 325 */ 326 cp = NULL; 327 if (lstat(pbuf, &sbuf) < 0) 328 cp = ".rhosts lstat failed"; 329 else if (!S_ISREG(sbuf.st_mode)) 330 cp = ".rhosts not regular file"; 331 else if (fstat(fileno(hostf), &sbuf) < 0) 332 cp = ".rhosts fstat failed"; 333 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 334 cp = "bad .rhosts owner"; 335 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 336 cp = ".rhosts writeable by other than owner"; 337 /* If there were any problems, quit. */ 338 if (cp) { 339 __rcmd_errstr = cp; 340 (void)fclose(hostf); 341 return (-1); 342 } 343 goto again; 344 } 345 return (-1); 346 } 347 348 /* 349 * XXX 350 * Don't make static, used by lpd(8). 351 * 352 * Returns 0 if ok, -1 if not ok. 353 */ 354 int 355 __ivaliduser(hostf, raddr, luser, ruser) 356 FILE *hostf; 357 u_long raddr; 358 const char *luser, *ruser; 359 { 360 register char *user, *p; 361 int ch; 362 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 363 const char *auser, *ahost; 364 int hostok, userok; 365 char rhost[MAXHOSTNAMELEN]; 366 struct hostent *hp; 367 char domain[MAXHOSTNAMELEN]; 368 369 getdomainname(domain, sizeof(domain)); 370 371 while (fgets(buf, sizeof(buf), hostf)) { 372 p = buf; 373 /* Skip lines that are too long. */ 374 if (strchr(p, '\n') == NULL) { 375 while ((ch = getc(hostf)) != '\n' && ch != EOF); 376 continue; 377 } 378 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 379 *p = isupper(*p) ? tolower(*p) : *p; 380 p++; 381 } 382 if (*p == ' ' || *p == '\t') { 383 *p++ = '\0'; 384 while (*p == ' ' || *p == '\t') 385 p++; 386 user = p; 387 while (*p != '\n' && *p != ' ' && 388 *p != '\t' && *p != '\0') 389 p++; 390 } else 391 user = p; 392 *p = '\0'; 393 394 if (p == buf) 395 continue; 396 397 auser = *user ? user : luser; 398 ahost = buf; 399 400 if ((hp = gethostbyaddr((char *) &raddr, 401 sizeof(raddr), AF_INET)) == NULL) { 402 abort(); 403 return -1; 404 } 405 (void) strncpy(rhost, hp->h_name, sizeof(rhost)); 406 rhost[sizeof(rhost) - 1] = '\0'; 407 408 if (ahost[0] == '+') 409 switch (ahost[1]) { 410 case '\0': 411 hostok = 1; 412 break; 413 414 case '@': 415 hostok = innetgr(&ahost[2], rhost, NULL, 416 domain); 417 break; 418 419 default: 420 hostok = __icheckhost(raddr, &ahost[1]); 421 break; 422 } 423 else if (ahost[0] == '-') 424 switch (ahost[1]) { 425 case '\0': 426 hostok = -1; 427 break; 428 429 case '@': 430 hostok = -innetgr(&ahost[2], rhost, NULL, 431 domain); 432 break; 433 434 default: 435 hostok = -__icheckhost(raddr, &ahost[1]); 436 break; 437 } 438 else 439 hostok = __icheckhost(raddr, ahost); 440 441 442 if (auser[0] == '+') 443 switch (auser[1]) { 444 case '\0': 445 userok = 1; 446 break; 447 448 case '@': 449 userok = innetgr(&auser[2], NULL, ruser, 450 domain); 451 break; 452 453 default: 454 userok = strcmp(ruser, &auser[1]) == 0; 455 break; 456 } 457 else if (auser[0] == '-') 458 switch (auser[1]) { 459 case '\0': 460 userok = -1; 461 break; 462 463 case '@': 464 userok = -innetgr(&auser[2], NULL, ruser, 465 domain); 466 break; 467 468 default: 469 userok = -(strcmp(ruser, &auser[1]) == 0); 470 break; 471 } 472 else 473 userok = strcmp(ruser, auser) == 0; 474 475 /* Check if one component did not match */ 476 if (hostok == 0 || userok == 0) 477 continue; 478 479 /* Check if we got a forbidden pair */ 480 if (userok == -1 || hostok == -1) 481 return -1; 482 483 /* Check if we got a valid pair */ 484 if (hostok == 1 && userok == 1) 485 return 0; 486 } 487 return -1; 488 } 489 490 /* 491 * Returns "true" if match, 0 if no match. 492 */ 493 static int 494 __icheckhost(raddr, lhost) 495 u_long raddr; 496 const char *lhost; 497 { 498 register struct hostent *hp; 499 register u_long laddr; 500 register char **pp; 501 502 /* Try for raw ip address first. */ 503 if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1) 504 return (raddr == laddr); 505 506 /* Better be a hostname. */ 507 if ((hp = gethostbyname(lhost)) == NULL) 508 return (0); 509 510 /* Spin through ip addresses. */ 511 for (pp = hp->h_addr_list; *pp; ++pp) 512 if (!bcmp(&raddr, *pp, sizeof(u_long))) 513 return (1); 514 515 /* No match. */ 516 return (0); 517 } 518