1 /* $NetBSD: rcmd.c,v 1.11 1995/02/25 06:20:53 cgd 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 1.11 1995/02/25 06:20:53 cgd 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_family = hp->h_addrtype; 101 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); 102 sin.sin_port = rport; 103 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 104 break; 105 (void)close(s); 106 if (errno == EADDRINUSE) { 107 lport--; 108 continue; 109 } 110 if (errno == ECONNREFUSED && timo <= 16) { 111 (void)sleep(timo); 112 timo *= 2; 113 continue; 114 } 115 if (hp->h_addr_list[1] != NULL) { 116 int oerrno = errno; 117 118 (void)fprintf(stderr, "connect to address %s: ", 119 inet_ntoa(sin.sin_addr)); 120 errno = oerrno; 121 perror(0); 122 hp->h_addr_list++; 123 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); 124 (void)fprintf(stderr, "Trying %s...\n", 125 inet_ntoa(sin.sin_addr)); 126 continue; 127 } 128 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno)); 129 sigsetmask(oldmask); 130 return (-1); 131 } 132 lport--; 133 if (fd2p == 0) { 134 write(s, "", 1); 135 lport = 0; 136 } else { 137 char num[8]; 138 int s2 = rresvport(&lport), s3; 139 int len = sizeof(from); 140 141 if (s2 < 0) 142 goto bad; 143 listen(s2, 1); 144 (void)snprintf(num, sizeof(num), "%d", lport); 145 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 146 (void)fprintf(stderr, 147 "rcmd: write (setting up stderr): %s\n", 148 strerror(errno)); 149 (void)close(s2); 150 goto bad; 151 } 152 FD_ZERO(&reads); 153 FD_SET(s, &reads); 154 FD_SET(s2, &reads); 155 errno = 0; 156 if (select(MAX(s, s2) + 1, &reads, 0, 0, 0) < 1 || 157 !FD_ISSET(s2, &reads)) { 158 if (errno != 0) 159 (void)fprintf(stderr, 160 "rcmd: select (setting up stderr): %s\n", 161 strerror(errno)); 162 else 163 (void)fprintf(stderr, 164 "select: protocol failure in circuit setup\n"); 165 (void)close(s2); 166 goto bad; 167 } 168 s3 = accept(s2, (struct sockaddr *)&from, &len); 169 (void)close(s2); 170 if (s3 < 0) { 171 (void)fprintf(stderr, 172 "rcmd: accept: %s\n", strerror(errno)); 173 lport = 0; 174 goto bad; 175 } 176 *fd2p = s3; 177 from.sin_port = ntohs((u_short)from.sin_port); 178 if (from.sin_family != AF_INET || 179 from.sin_port >= IPPORT_RESERVED || 180 from.sin_port < IPPORT_RESERVED / 2) { 181 (void)fprintf(stderr, 182 "socket: protocol failure in circuit setup.\n"); 183 goto bad2; 184 } 185 } 186 (void)write(s, locuser, strlen(locuser)+1); 187 (void)write(s, remuser, strlen(remuser)+1); 188 (void)write(s, cmd, strlen(cmd)+1); 189 if (read(s, &c, 1) != 1) { 190 (void)fprintf(stderr, 191 "rcmd: %s: %s\n", *ahost, strerror(errno)); 192 goto bad2; 193 } 194 if (c != 0) { 195 while (read(s, &c, 1) == 1) { 196 (void)write(STDERR_FILENO, &c, 1); 197 if (c == '\n') 198 break; 199 } 200 goto bad2; 201 } 202 sigsetmask(oldmask); 203 return (s); 204 bad2: 205 if (lport) 206 (void)close(*fd2p); 207 bad: 208 (void)close(s); 209 sigsetmask(oldmask); 210 return (-1); 211 } 212 213 int 214 rresvport(alport) 215 int *alport; 216 { 217 struct sockaddr_in sin; 218 int s; 219 220 sin.sin_family = AF_INET; 221 sin.sin_addr.s_addr = INADDR_ANY; 222 s = socket(AF_INET, SOCK_STREAM, 0); 223 if (s < 0) 224 return (-1); 225 for (;;) { 226 sin.sin_port = htons((u_short)*alport); 227 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 228 return (s); 229 if (errno != EADDRINUSE) { 230 (void)close(s); 231 return (-1); 232 } 233 (*alport)--; 234 if (*alport == IPPORT_RESERVED/2) { 235 (void)close(s); 236 errno = EAGAIN; /* close */ 237 return (-1); 238 } 239 } 240 } 241 242 int __check_rhosts_file = 1; 243 char *__rcmd_errstr; 244 245 int 246 ruserok(rhost, superuser, ruser, luser) 247 const char *rhost, *ruser, *luser; 248 int superuser; 249 { 250 struct hostent *hp; 251 char **ap; 252 int i; 253 #define MAXADDRS 35 254 u_long addrs[MAXADDRS + 1]; 255 256 if ((hp = gethostbyname(rhost)) == NULL) 257 return (-1); 258 for (i = 0, ap = hp->h_addr_list; *ap && i < MAXADDRS; ++ap, ++i) 259 bcopy(*ap, &addrs[i], sizeof(addrs[i])); 260 addrs[i] = 0; 261 262 for (i = 0; i < MAXADDRS && addrs[i]; i++) 263 if (iruserok(addrs[i], superuser, ruser, luser) == 0) 264 return (0); 265 return (-1); 266 } 267 268 /* 269 * New .rhosts strategy: We are passed an ip address. We spin through 270 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 271 * has ip addresses, we don't have to trust a nameserver. When it 272 * contains hostnames, we spin through the list of addresses the nameserver 273 * gives us and look for a match. 274 * 275 * Returns 0 if ok, -1 if not ok. 276 */ 277 int 278 iruserok(raddr, superuser, ruser, luser) 279 u_long raddr; 280 int superuser; 281 const char *ruser, *luser; 282 { 283 register char *cp; 284 struct stat sbuf; 285 struct passwd *pwd; 286 FILE *hostf; 287 uid_t uid; 288 int first; 289 char pbuf[MAXPATHLEN]; 290 291 first = 1; 292 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 293 again: 294 if (hostf) { 295 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) { 296 (void)fclose(hostf); 297 return (0); 298 } 299 (void)fclose(hostf); 300 } 301 if (first == 1 && (__check_rhosts_file || superuser)) { 302 first = 0; 303 if ((pwd = getpwnam(luser)) == NULL) 304 return (-1); 305 (void)strcpy(pbuf, pwd->pw_dir); 306 (void)strcat(pbuf, "/.rhosts"); 307 308 /* 309 * Change effective uid while opening .rhosts. If root and 310 * reading an NFS mounted file system, can't read files that 311 * are protected read/write owner only. 312 */ 313 uid = geteuid(); 314 (void)seteuid(pwd->pw_uid); 315 hostf = fopen(pbuf, "r"); 316 (void)seteuid(uid); 317 318 if (hostf == NULL) 319 return (-1); 320 /* 321 * If not a regular file, or is owned by someone other than 322 * user or root or if writeable by anyone but the owner, quit. 323 */ 324 cp = NULL; 325 if (lstat(pbuf, &sbuf) < 0) 326 cp = ".rhosts lstat failed"; 327 else if (!S_ISREG(sbuf.st_mode)) 328 cp = ".rhosts not regular file"; 329 else if (fstat(fileno(hostf), &sbuf) < 0) 330 cp = ".rhosts fstat failed"; 331 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 332 cp = "bad .rhosts owner"; 333 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 334 cp = ".rhosts writeable by other than owner"; 335 /* If there were any problems, quit. */ 336 if (cp) { 337 __rcmd_errstr = cp; 338 (void)fclose(hostf); 339 return (-1); 340 } 341 goto again; 342 } 343 return (-1); 344 } 345 346 /* 347 * XXX 348 * Don't make static, used by lpd(8). 349 * 350 * Returns 0 if ok, -1 if not ok. 351 */ 352 int 353 __ivaliduser(hostf, raddr, luser, ruser) 354 FILE *hostf; 355 u_long raddr; 356 const char *luser, *ruser; 357 { 358 register char *user, *p; 359 int ch; 360 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 361 const char *auser, *ahost; 362 int hostok, userok; 363 char rhost[MAXHOSTNAMELEN]; 364 struct hostent *hp; 365 char domain[MAXHOSTNAMELEN]; 366 367 getdomainname(domain, sizeof(domain)); 368 369 while (fgets(buf, sizeof(buf), hostf)) { 370 p = buf; 371 /* Skip lines that are too long. */ 372 if (strchr(p, '\n') == NULL) { 373 while ((ch = getc(hostf)) != '\n' && ch != EOF); 374 continue; 375 } 376 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 377 *p = isupper(*p) ? tolower(*p) : *p; 378 p++; 379 } 380 if (*p == ' ' || *p == '\t') { 381 *p++ = '\0'; 382 while (*p == ' ' || *p == '\t') 383 p++; 384 user = p; 385 while (*p != '\n' && *p != ' ' && 386 *p != '\t' && *p != '\0') 387 p++; 388 } else 389 user = p; 390 *p = '\0'; 391 392 if (p == buf) 393 continue; 394 395 auser = *user ? user : luser; 396 ahost = buf; 397 398 if ((hp = gethostbyaddr((char *) &raddr, 399 sizeof(raddr), AF_INET)) == NULL) { 400 abort(); 401 return -1; 402 } 403 (void) strncpy(rhost, hp->h_name, sizeof(rhost)); 404 rhost[sizeof(rhost) - 1] = '\0'; 405 406 if (ahost[0] == '+') 407 switch (ahost[1]) { 408 case '\0': 409 hostok = 1; 410 break; 411 412 case '@': 413 hostok = innetgr(&ahost[2], rhost, NULL, 414 domain); 415 break; 416 417 default: 418 hostok = __icheckhost(raddr, &ahost[1]); 419 break; 420 } 421 else if (ahost[0] == '-') 422 switch (ahost[1]) { 423 case '\0': 424 hostok = -1; 425 break; 426 427 case '@': 428 hostok = -innetgr(&ahost[2], rhost, NULL, 429 domain); 430 break; 431 432 default: 433 hostok = -__icheckhost(raddr, &ahost[1]); 434 break; 435 } 436 else 437 hostok = __icheckhost(raddr, ahost); 438 439 440 if (auser[0] == '+') 441 switch (auser[1]) { 442 case '\0': 443 userok = 1; 444 break; 445 446 case '@': 447 userok = innetgr(&auser[2], NULL, ruser, 448 domain); 449 break; 450 451 default: 452 userok = strcmp(ruser, &auser[1]) == 0; 453 break; 454 } 455 else if (auser[0] == '-') 456 switch (auser[1]) { 457 case '\0': 458 userok = -1; 459 break; 460 461 case '@': 462 userok = -innetgr(&auser[2], NULL, ruser, 463 domain); 464 break; 465 466 default: 467 userok = -(strcmp(ruser, &auser[1]) == 0); 468 break; 469 } 470 else 471 userok = strcmp(ruser, auser) == 0; 472 473 /* Check if one component did not match */ 474 if (hostok == 0 || userok == 0) 475 continue; 476 477 /* Check if we got a forbidden pair */ 478 if (userok == -1 || hostok == -1) 479 return -1; 480 481 /* Check if we got a valid pair */ 482 if (hostok == 1 && userok == 1) 483 return 0; 484 } 485 return -1; 486 } 487 488 /* 489 * Returns "true" if match, 0 if no match. 490 */ 491 static int 492 __icheckhost(raddr, lhost) 493 u_long raddr; 494 const char *lhost; 495 { 496 register struct hostent *hp; 497 register u_long laddr; 498 register char **pp; 499 500 /* Try for raw ip address first. */ 501 if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1) 502 return (raddr == laddr); 503 504 /* Better be a hostname. */ 505 if ((hp = gethostbyname(lhost)) == NULL) 506 return (0); 507 508 /* Spin through ip addresses. */ 509 for (pp = hp->h_addr_list; *pp; ++pp) 510 if (!bcmp(&raddr, *pp, sizeof(u_long))) 511 return (1); 512 513 /* No match. */ 514 return (0); 515 } 516