1 /* 2 * Copyright (c) 1983, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <sys/param.h> 41 #include <sys/socket.h> 42 #include <sys/stat.h> 43 44 #include <netinet/in.h> 45 #include <arpa/inet.h> 46 47 #include <signal.h> 48 #include <fcntl.h> 49 #include <netdb.h> 50 #include <unistd.h> 51 #include <pwd.h> 52 #include <errno.h> 53 #include <stdio.h> 54 #include <ctype.h> 55 #include <string.h> 56 #ifdef YP 57 #include <rpc/rpc.h> 58 #include <rpcsvc/yp_prot.h> 59 #include <rpcsvc/ypclnt.h> 60 #endif 61 62 extern int innetgr __P(( const char *, const char *, const char *, const char * )); 63 64 #define max(a, b) ((a > b) ? a : b) 65 66 int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *)); 67 static int __icheckhost __P((u_int32_t, char *)); 68 69 int 70 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 71 char **ahost; 72 u_short rport; 73 const char *locuser, *remuser, *cmd; 74 int *fd2p; 75 { 76 struct hostent *hp; 77 struct sockaddr_in sin, from; 78 fd_set reads; 79 long oldmask; 80 pid_t pid; 81 int s, lport, timo; 82 char c; 83 84 pid = getpid(); 85 hp = gethostbyname(*ahost); 86 if (hp == NULL) { 87 herror(*ahost); 88 return (-1); 89 } 90 *ahost = hp->h_name; 91 oldmask = sigblock(sigmask(SIGURG)); 92 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 93 s = rresvport(&lport); 94 if (s < 0) { 95 if (errno == EAGAIN) 96 (void)fprintf(stderr, 97 "rcmd: socket: All ports in use\n"); 98 else 99 (void)fprintf(stderr, "rcmd: socket: %s\n", 100 strerror(errno)); 101 sigsetmask(oldmask); 102 return (-1); 103 } 104 fcntl(s, F_SETOWN, pid); 105 bzero(&sin, sizeof sin); 106 sin.sin_len = sizeof(struct sockaddr_in); 107 sin.sin_family = hp->h_addrtype; 108 sin.sin_port = rport; 109 bcopy(hp->h_addr_list[0], &sin.sin_addr, MIN(hp->h_length, sizeof sin.sin_addr)); 110 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 111 break; 112 (void)close(s); 113 if (errno == EADDRINUSE) { 114 lport--; 115 continue; 116 } 117 if (errno == ECONNREFUSED && timo <= 16) { 118 (void)sleep(timo); 119 timo *= 2; 120 continue; 121 } 122 if (hp->h_addr_list[1] != NULL) { 123 int oerrno = errno; 124 125 (void)fprintf(stderr, "connect to address %s: ", 126 inet_ntoa(sin.sin_addr)); 127 errno = oerrno; 128 perror(0); 129 hp->h_addr_list++; 130 bcopy(hp->h_addr_list[0], &sin.sin_addr, MIN(hp->h_length, sizeof sin.sin_addr)); 131 (void)fprintf(stderr, "Trying %s...\n", 132 inet_ntoa(sin.sin_addr)); 133 continue; 134 } 135 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno)); 136 sigsetmask(oldmask); 137 return (-1); 138 } 139 lport--; 140 if (fd2p == 0) { 141 write(s, "", 1); 142 lport = 0; 143 } else { 144 char num[8]; 145 int s2 = rresvport(&lport), s3; 146 int len = sizeof(from); 147 int nfds; 148 149 if (s2 < 0) 150 goto bad; 151 listen(s2, 1); 152 (void)snprintf(num, sizeof(num), "%d", lport); 153 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 154 (void)fprintf(stderr, 155 "rcmd: write (setting up stderr): %s\n", 156 strerror(errno)); 157 (void)close(s2); 158 goto bad; 159 } 160 nfds = max(s, s2)+1; 161 if(nfds > FD_SETSIZE) { 162 fprintf(stderr, "rcmd: too many files\n"); 163 (void)close(s2); 164 goto bad; 165 } 166 again: 167 FD_ZERO(&reads); 168 FD_SET(s, &reads); 169 FD_SET(s2, &reads); 170 errno = 0; 171 if (select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){ 172 if (errno != 0) 173 (void)fprintf(stderr, 174 "rcmd: select (setting up stderr): %s\n", 175 strerror(errno)); 176 else 177 (void)fprintf(stderr, 178 "select: protocol failure in circuit setup\n"); 179 (void)close(s2); 180 goto bad; 181 } 182 s3 = accept(s2, (struct sockaddr *)&from, &len); 183 /* 184 * XXX careful for ftp bounce attacks. If discovered, shut them 185 * down and check for the real auxiliary channel to connect. 186 */ 187 if (from.sin_family == AF_INET && from.sin_port == htons(20)) { 188 close(s3); 189 goto again; 190 } 191 (void)close(s2); 192 if (s3 < 0) { 193 (void)fprintf(stderr, 194 "rcmd: accept: %s\n", strerror(errno)); 195 lport = 0; 196 goto bad; 197 } 198 *fd2p = s3; 199 from.sin_port = ntohs((u_short)from.sin_port); 200 if (from.sin_family != AF_INET || 201 from.sin_port >= IPPORT_RESERVED || 202 from.sin_port < IPPORT_RESERVED / 2) { 203 (void)fprintf(stderr, 204 "socket: protocol failure in circuit setup.\n"); 205 goto bad2; 206 } 207 } 208 (void)write(s, locuser, strlen(locuser)+1); 209 (void)write(s, remuser, strlen(remuser)+1); 210 (void)write(s, cmd, strlen(cmd)+1); 211 if (read(s, &c, 1) != 1) { 212 (void)fprintf(stderr, 213 "rcmd: %s: %s\n", *ahost, strerror(errno)); 214 goto bad2; 215 } 216 if (c != 0) { 217 while (read(s, &c, 1) == 1) { 218 (void)write(STDERR_FILENO, &c, 1); 219 if (c == '\n') 220 break; 221 } 222 goto bad2; 223 } 224 sigsetmask(oldmask); 225 return (s); 226 bad2: 227 if (lport) 228 (void)close(*fd2p); 229 bad: 230 (void)close(s); 231 sigsetmask(oldmask); 232 return (-1); 233 } 234 235 int 236 rresvport(alport) 237 int *alport; 238 { 239 struct sockaddr_in sin; 240 int s; 241 242 bzero(&sin, sizeof sin); 243 sin.sin_len = sizeof(struct sockaddr_in); 244 sin.sin_family = AF_INET; 245 sin.sin_addr.s_addr = INADDR_ANY; 246 s = socket(AF_INET, SOCK_STREAM, 0); 247 if (s < 0) 248 return (-1); 249 #if 0 /* compat_exact_traditional_rresvport_semantics */ 250 sin.sin_port = htons((u_short)*alport); 251 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 252 return (s); 253 if (errno != EADDRINUSE) { 254 (void)close(s); 255 return (-1); 256 } 257 #endif 258 sin.sin_port = 0; 259 if (bindresvport(s, &sin) == -1) { 260 (void)close(s); 261 return (-1); 262 } 263 *alport = (int)ntohs(sin.sin_port); 264 return (s); 265 } 266 267 int __check_rhosts_file = 1; 268 char *__rcmd_errstr; 269 270 int 271 ruserok(rhost, superuser, ruser, luser) 272 const char *rhost, *ruser, *luser; 273 int superuser; 274 { 275 struct hostent *hp; 276 u_int32_t addr; 277 char **ap; 278 279 if ((hp = gethostbyname(rhost)) == NULL) 280 return (-1); 281 for (ap = hp->h_addr_list; *ap; ++ap) { 282 bcopy(*ap, &addr, sizeof(addr)); 283 if (iruserok(addr, superuser, ruser, luser) == 0) 284 return (0); 285 } 286 return (-1); 287 } 288 289 /* 290 * New .rhosts strategy: We are passed an ip address. We spin through 291 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 292 * has ip addresses, we don't have to trust a nameserver. When it 293 * contains hostnames, we spin through the list of addresses the nameserver 294 * gives us and look for a match. 295 * 296 * Returns 0 if ok, -1 if not ok. 297 */ 298 int 299 iruserok(raddr, superuser, ruser, luser) 300 unsigned long raddr; 301 int superuser; 302 const char *ruser, *luser; 303 { 304 register char *cp; 305 struct stat sbuf; 306 struct passwd *pwd; 307 FILE *hostf; 308 uid_t uid; 309 int first; 310 char pbuf[MAXPATHLEN]; 311 312 first = 1; 313 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 314 again: 315 if (hostf) { 316 if (__ivaliduser(hostf, (u_int32_t)raddr, luser, ruser) == 0) { 317 (void)fclose(hostf); 318 return (0); 319 } 320 (void)fclose(hostf); 321 } 322 if (first == 1 && (__check_rhosts_file || superuser)) { 323 first = 0; 324 if ((pwd = getpwnam(luser)) == NULL) 325 return (-1); 326 (void)strcpy(pbuf, pwd->pw_dir); 327 (void)strcat(pbuf, "/.rhosts"); 328 329 /* 330 * Change effective uid while opening .rhosts. If root and 331 * reading an NFS mounted file system, can't read files that 332 * are protected read/write owner only. 333 */ 334 uid = geteuid(); 335 (void)seteuid(pwd->pw_uid); 336 hostf = fopen(pbuf, "r"); 337 (void)seteuid(uid); 338 339 if (hostf == NULL) 340 return (-1); 341 /* 342 * If not a regular file, or is owned by someone other than 343 * user or root or if writeable by anyone but the owner, quit. 344 */ 345 cp = NULL; 346 if (lstat(pbuf, &sbuf) < 0) 347 cp = ".rhosts lstat failed"; 348 else if (!S_ISREG(sbuf.st_mode)) 349 cp = ".rhosts not regular file"; 350 else if (fstat(fileno(hostf), &sbuf) < 0) 351 cp = ".rhosts fstat failed"; 352 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 353 cp = "bad .rhosts owner"; 354 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 355 cp = ".rhosts writeable by other than owner"; 356 /* If there were any problems, quit. */ 357 if (cp) { 358 __rcmd_errstr = cp; 359 (void)fclose(hostf); 360 return (-1); 361 } 362 goto again; 363 } 364 return (-1); 365 } 366 367 /* 368 * XXX 369 * Don't make static, used by lpd(8). 370 * 371 * Returns 0 if ok, -1 if not ok. 372 */ 373 int 374 __ivaliduser(hostf, raddr, luser, ruser) 375 FILE *hostf; 376 u_int32_t raddr; 377 const char *luser, *ruser; 378 { 379 register char *user, *p; 380 int ch; 381 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 382 char hname[MAXHOSTNAMELEN]; 383 struct hostent *hp; 384 /* Presumed guilty until proven innocent. */ 385 int userok = 0, hostok = 0; 386 #ifdef YP 387 char *ypdomain; 388 389 if (yp_get_default_domain(&ypdomain)) 390 ypdomain = NULL; 391 #else 392 #define ypdomain NULL 393 #endif 394 /* We need to get the damn hostname back for netgroup matching. */ 395 if ((hp = gethostbyaddr((char *)&raddr, sizeof(u_int32_t), 396 AF_INET)) == NULL) 397 return (-1); 398 strncpy(hname, hp->h_name, sizeof(hname)); 399 hname[sizeof(hname) - 1] = '\0'; 400 401 while (fgets(buf, sizeof(buf), hostf)) { 402 p = buf; 403 /* Skip lines that are too long. */ 404 if (strchr(p, '\n') == NULL) { 405 while ((ch = getc(hostf)) != '\n' && ch != EOF); 406 continue; 407 } 408 if (*p == '\n' || *p == '#') { 409 /* comment... */ 410 continue; 411 } 412 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 413 *p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p; 414 p++; 415 } 416 if (*p == ' ' || *p == '\t') { 417 *p++ = '\0'; 418 while (*p == ' ' || *p == '\t') 419 p++; 420 user = p; 421 while (*p != '\n' && *p != ' ' && 422 *p != '\t' && *p != '\0') 423 p++; 424 } else 425 user = p; 426 *p = '\0'; 427 /* 428 * Do +/- and +@/-@ checking. This looks really nasty, 429 * but it matches SunOS's behavior so far as I can tell. 430 */ 431 switch(buf[0]) { 432 case '+': 433 if (!buf[1]) { /* '+' matches all hosts */ 434 hostok = 1; 435 break; 436 } 437 if (buf[1] == '@') /* match a host by netgroup */ 438 hostok = innetgr((char *)&buf[2], 439 (char *)&hname, NULL, ypdomain); 440 else /* match a host by addr */ 441 hostok = __icheckhost(raddr,(char *)&buf[1]); 442 break; 443 case '-': /* reject '-' hosts and all their users */ 444 if (buf[1] == '@') { 445 if (innetgr((char *)&buf[2], 446 (char *)&hname, NULL, ypdomain)) 447 return(-1); 448 } else { 449 if (__icheckhost(raddr,(char *)&buf[1])) 450 return(-1); 451 } 452 break; 453 default: /* if no '+' or '-', do a simple match */ 454 hostok = __icheckhost(raddr, buf); 455 break; 456 } 457 switch(*user) { 458 case '+': 459 if (!*(user+1)) { /* '+' matches all users */ 460 userok = 1; 461 break; 462 } 463 if (*(user+1) == '@') /* match a user by netgroup */ 464 userok = innetgr(user+2, NULL, ruser, ypdomain); 465 else /* match a user by direct specification */ 466 userok = !(strcmp(ruser, user+1)); 467 break; 468 case '-': /* if we matched a hostname, */ 469 if (hostok) { /* check for user field rejections */ 470 if (!*(user+1)) 471 return(-1); 472 if (*(user+1) == '@') { 473 if (innetgr(user+2, NULL, 474 ruser, ypdomain)) 475 return(-1); 476 } else { 477 if (!strcmp(ruser, user+1)) 478 return(-1); 479 } 480 } 481 break; 482 default: /* no rejections: try to match the user */ 483 if (hostok) 484 userok = !(strcmp(ruser,*user ? user : luser)); 485 break; 486 } 487 if (hostok && userok) 488 return(0); 489 } 490 return (-1); 491 } 492 493 /* 494 * Returns "true" if match, 0 if no match. 495 */ 496 static int 497 __icheckhost(raddr, lhost) 498 u_int32_t raddr; 499 register char *lhost; 500 { 501 register struct hostent *hp; 502 register u_int32_t laddr; 503 register char **pp; 504 505 /* Try for raw ip address first. */ 506 if (isdigit((unsigned char)*lhost) && (u_int32_t)(laddr = inet_addr(lhost)) != -1) 507 return (raddr == laddr); 508 509 /* Better be a hostname. */ 510 if ((hp = gethostbyname(lhost)) == NULL) 511 return (0); 512 513 /* Spin through ip addresses. */ 514 for (pp = hp->h_addr_list; *pp; ++pp) 515 if (!bcmp(&raddr, *pp, sizeof(u_int32_t))) 516 return (1); 517 518 /* No match. */ 519 return (0); 520 } 521