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 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/param.h> 39 #include <sys/socket.h> 40 #include <sys/stat.h> 41 42 #include <netinet/in.h> 43 #include <arpa/inet.h> 44 45 #include <signal.h> 46 #include <fcntl.h> 47 #include <netdb.h> 48 #include <unistd.h> 49 #include <pwd.h> 50 #include <errno.h> 51 #include <stdio.h> 52 #include <ctype.h> 53 #include <string.h> 54 #ifdef YP 55 #include <rpc/rpc.h> 56 #include <rpcsvc/yp_prot.h> 57 #include <rpcsvc/ypclnt.h> 58 #endif 59 60 #define max(a, b) ((a > b) ? a : b) 61 62 int __ivaliduser __P((FILE *, u_long, const char *, const char *)); 63 static int __icheckhost __P((u_long, char *)); 64 65 int 66 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 67 char **ahost; 68 u_short rport; 69 const char *locuser, *remuser, *cmd; 70 int *fd2p; 71 { 72 struct hostent *hp; 73 struct sockaddr_in sin, from; 74 fd_set reads; 75 long oldmask; 76 pid_t pid; 77 int s, lport, timo; 78 char c; 79 80 pid = getpid(); 81 hp = gethostbyname(*ahost); 82 if (hp == NULL) { 83 herror(*ahost); 84 return (-1); 85 } 86 *ahost = hp->h_name; 87 oldmask = sigblock(sigmask(SIGURG)); 88 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 89 s = rresvport(&lport); 90 if (s < 0) { 91 if (errno == EAGAIN) 92 (void)fprintf(stderr, 93 "rcmd: socket: All ports in use\n"); 94 else 95 (void)fprintf(stderr, "rcmd: socket: %s\n", 96 strerror(errno)); 97 sigsetmask(oldmask); 98 return (-1); 99 } 100 fcntl(s, F_SETOWN, pid); 101 sin.sin_family = hp->h_addrtype; 102 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length); 103 sin.sin_port = rport; 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 int nfds; 142 143 if (s2 < 0) 144 goto bad; 145 listen(s2, 1); 146 (void)snprintf(num, sizeof(num), "%d", lport); 147 if (write(s, num, strlen(num)+1) != strlen(num)+1) { 148 (void)fprintf(stderr, 149 "rcmd: write (setting up stderr): %s\n", 150 strerror(errno)); 151 (void)close(s2); 152 goto bad; 153 } 154 nfds = max(s, s2)+1; 155 if(nfds > FD_SETSIZE) { 156 fprintf(stderr, "rcmd: too many files\n"); 157 (void)close(s2); 158 goto bad; 159 } 160 FD_ZERO(&reads); 161 FD_SET(s, &reads); 162 FD_SET(s2, &reads); 163 errno = 0; 164 if (select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){ 165 if (errno != 0) 166 (void)fprintf(stderr, 167 "rcmd: select (setting up stderr): %s\n", 168 strerror(errno)); 169 else 170 (void)fprintf(stderr, 171 "select: protocol failure in circuit setup\n"); 172 (void)close(s2); 173 goto bad; 174 } 175 s3 = accept(s2, (struct sockaddr *)&from, &len); 176 (void)close(s2); 177 if (s3 < 0) { 178 (void)fprintf(stderr, 179 "rcmd: accept: %s\n", strerror(errno)); 180 lport = 0; 181 goto bad; 182 } 183 *fd2p = s3; 184 from.sin_port = ntohs((u_short)from.sin_port); 185 if (from.sin_family != AF_INET || 186 from.sin_port >= IPPORT_RESERVED || 187 from.sin_port < IPPORT_RESERVED / 2) { 188 (void)fprintf(stderr, 189 "socket: protocol failure in circuit setup.\n"); 190 goto bad2; 191 } 192 } 193 (void)write(s, locuser, strlen(locuser)+1); 194 (void)write(s, remuser, strlen(remuser)+1); 195 (void)write(s, cmd, strlen(cmd)+1); 196 if (read(s, &c, 1) != 1) { 197 (void)fprintf(stderr, 198 "rcmd: %s: %s\n", *ahost, strerror(errno)); 199 goto bad2; 200 } 201 if (c != 0) { 202 while (read(s, &c, 1) == 1) { 203 (void)write(STDERR_FILENO, &c, 1); 204 if (c == '\n') 205 break; 206 } 207 goto bad2; 208 } 209 sigsetmask(oldmask); 210 return (s); 211 bad2: 212 if (lport) 213 (void)close(*fd2p); 214 bad: 215 (void)close(s); 216 sigsetmask(oldmask); 217 return (-1); 218 } 219 220 int 221 rresvport(alport) 222 int *alport; 223 { 224 struct sockaddr_in sin; 225 int s; 226 227 sin.sin_family = AF_INET; 228 sin.sin_addr.s_addr = INADDR_ANY; 229 s = socket(AF_INET, SOCK_STREAM, 0); 230 if (s < 0) 231 return (-1); 232 for (;;) { 233 sin.sin_port = htons((u_short)*alport); 234 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 235 return (s); 236 if (errno != EADDRINUSE) { 237 (void)close(s); 238 return (-1); 239 } 240 (*alport)--; 241 if (*alport == IPPORT_RESERVED/2) { 242 (void)close(s); 243 errno = EAGAIN; /* close */ 244 return (-1); 245 } 246 } 247 } 248 249 int __check_rhosts_file = 1; 250 char *__rcmd_errstr; 251 252 int 253 ruserok(rhost, superuser, ruser, luser) 254 const char *rhost, *ruser, *luser; 255 int superuser; 256 { 257 struct hostent *hp; 258 u_long addr; 259 char **ap; 260 261 if ((hp = gethostbyname(rhost)) == NULL) 262 return (-1); 263 for (ap = hp->h_addr_list; *ap; ++ap) { 264 bcopy(*ap, &addr, sizeof(addr)); 265 if (iruserok(addr, superuser, ruser, luser) == 0) 266 return (0); 267 } 268 return (-1); 269 } 270 271 /* 272 * New .rhosts strategy: We are passed an ip address. We spin through 273 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 274 * has ip addresses, we don't have to trust a nameserver. When it 275 * contains hostnames, we spin through the list of addresses the nameserver 276 * gives us and look for a match. 277 * 278 * Returns 0 if ok, -1 if not ok. 279 */ 280 int 281 iruserok(raddr, superuser, ruser, luser) 282 u_long raddr; 283 int superuser; 284 const char *ruser, *luser; 285 { 286 register char *cp; 287 struct stat sbuf; 288 struct passwd *pwd; 289 FILE *hostf; 290 uid_t uid; 291 int first; 292 char pbuf[MAXPATHLEN]; 293 294 first = 1; 295 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 296 again: 297 if (hostf) { 298 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) { 299 (void)fclose(hostf); 300 return (0); 301 } 302 (void)fclose(hostf); 303 } 304 if (first == 1 && (__check_rhosts_file || superuser)) { 305 first = 0; 306 if ((pwd = getpwnam(luser)) == NULL) 307 return (-1); 308 (void)strcpy(pbuf, pwd->pw_dir); 309 (void)strcat(pbuf, "/.rhosts"); 310 311 /* 312 * Change effective uid while opening .rhosts. If root and 313 * reading an NFS mounted file system, can't read files that 314 * are protected read/write owner only. 315 */ 316 uid = geteuid(); 317 (void)seteuid(pwd->pw_uid); 318 hostf = fopen(pbuf, "r"); 319 (void)seteuid(uid); 320 321 if (hostf == NULL) 322 return (-1); 323 /* 324 * If not a regular file, or is owned by someone other than 325 * user or root or if writeable by anyone but the owner, quit. 326 */ 327 cp = NULL; 328 if (lstat(pbuf, &sbuf) < 0) 329 cp = ".rhosts lstat failed"; 330 else if (!S_ISREG(sbuf.st_mode)) 331 cp = ".rhosts not regular file"; 332 else if (fstat(fileno(hostf), &sbuf) < 0) 333 cp = ".rhosts fstat failed"; 334 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 335 cp = "bad .rhosts owner"; 336 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 337 cp = ".rhosts writeable by other than owner"; 338 /* If there were any problems, quit. */ 339 if (cp) { 340 __rcmd_errstr = cp; 341 (void)fclose(hostf); 342 return (-1); 343 } 344 goto again; 345 } 346 return (-1); 347 } 348 349 /* 350 * XXX 351 * Don't make static, used by lpd(8). 352 * 353 * Returns 0 if ok, -1 if not ok. 354 */ 355 int 356 __ivaliduser(hostf, raddr, luser, ruser) 357 FILE *hostf; 358 u_long raddr; 359 const char *luser, *ruser; 360 { 361 register char *user, *p; 362 int ch; 363 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 364 char hname[MAXHOSTNAMELEN]; 365 struct hostent *hp; 366 /* Presumed guilty until proven innocent. */ 367 int userok = 0, hostok = 0; 368 #ifdef YP 369 char *ypdomain; 370 371 if (yp_get_default_domain(&ypdomain)) 372 ypdomain = NULL; 373 #else 374 #define ypdomain NULL 375 #endif 376 /* We need to get the damn hostname back for netgroup matching. */ 377 if ((hp = gethostbyaddr((char *)&raddr, sizeof(u_long), 378 AF_INET)) == NULL) 379 return (-1); 380 strcpy(hname, hp->h_name); 381 382 while (fgets(buf, sizeof(buf), hostf)) { 383 p = buf; 384 /* Skip lines that are too long. */ 385 if (strchr(p, '\n') == NULL) { 386 while ((ch = getc(hostf)) != '\n' && ch != EOF); 387 continue; 388 } 389 if (*p == '\n' || *p == '#') { 390 /* comment... */ 391 continue; 392 } 393 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 394 *p = isupper(*p) ? tolower(*p) : *p; 395 p++; 396 } 397 if (*p == ' ' || *p == '\t') { 398 *p++ = '\0'; 399 while (*p == ' ' || *p == '\t') 400 p++; 401 user = p; 402 while (*p != '\n' && *p != ' ' && 403 *p != '\t' && *p != '\0') 404 p++; 405 } else 406 user = p; 407 *p = '\0'; 408 /* 409 * Do +/- and +@/-@ checking. This looks really nasty, 410 * but it matches SunOS's behavior so far as I can tell. 411 */ 412 switch(buf[0]) { 413 case '+': 414 if (!buf[1]) { /* '+' matches all hosts */ 415 hostok = 1; 416 break; 417 } 418 if (buf[1] == '@') /* match a host by netgroup */ 419 hostok = innetgr((char *)&buf[2], 420 (char *)&hname, NULL, ypdomain); 421 else /* match a host by addr */ 422 hostok = __icheckhost(raddr,(char *)&buf[1]); 423 break; 424 case '-': /* reject '-' hosts and all their users */ 425 if (buf[1] == '@') { 426 if (innetgr((char *)&buf[2], 427 (char *)&hname, NULL, ypdomain)) 428 return(-1); 429 } else { 430 if (__icheckhost(raddr,(char *)&buf[1])) 431 return(-1); 432 } 433 break; 434 default: /* if no '+' or '-', do a simple match */ 435 hostok = __icheckhost(raddr, buf); 436 break; 437 } 438 switch(*user) { 439 case '+': 440 if (!*(user+1)) { /* '+' matches all users */ 441 userok = 1; 442 break; 443 } 444 if (*(user+1) == '@') /* match a user by netgroup */ 445 userok = innetgr(user+2, NULL, ruser, ypdomain); 446 else /* match a user by direct specification */ 447 userok = !(strcmp(ruser, user+1)); 448 break; 449 case '-': /* if we matched a hostname, */ 450 if (hostok) { /* check for user field rejections */ 451 if (!*(user+1)) 452 return(-1); 453 if (*(user+1) == '@') { 454 if (innetgr(user+2, NULL, 455 ruser, ypdomain)) 456 return(-1); 457 } else { 458 if (!strcmp(ruser, user+1)) 459 return(-1); 460 } 461 } 462 break; 463 default: /* no rejections: try to match the user */ 464 if (hostok) 465 userok = !(strcmp(ruser,*user ? user : luser)); 466 break; 467 } 468 if (hostok && userok) 469 return(0); 470 } 471 return (-1); 472 } 473 474 /* 475 * Returns "true" if match, 0 if no match. 476 */ 477 static int 478 __icheckhost(raddr, lhost) 479 u_long raddr; 480 register char *lhost; 481 { 482 register struct hostent *hp; 483 register u_long laddr; 484 register char **pp; 485 486 /* Try for raw ip address first. */ 487 if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1) 488 return (raddr == laddr); 489 490 /* Better be a hostname. */ 491 if ((hp = gethostbyname(lhost)) == NULL) 492 return (0); 493 494 /* Spin through ip addresses. */ 495 for (pp = hp->h_addr_list; *pp; ++pp) 496 if (!bcmp(&raddr, *pp, sizeof(u_long))) 497 return (1); 498 499 /* No match. */ 500 return (0); 501 } 502