1 /* 2 * Copyright (c) 1983, 1988 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 char copyright[] = 20 "@(#) Copyright (c) 1983, 1988 The Regents of the University of California.\n\ 21 All rights reserved.\n"; 22 #endif /* not lint */ 23 24 #ifndef lint 25 static char sccsid[] = "@(#)rlogind.c 5.22.1.4 (Berkeley) 01/25/89"; 26 #endif /* not lint */ 27 28 /* 29 * remote login server: 30 * \0 31 * remuser\0 32 * locuser\0 33 * terminal_type/speed\0 34 * data 35 * 36 * Automatic login protocol is done here, using login -f upon success, 37 * unless OLD_LOGIN is defined (then done in login, ala 4.2/4.3BSD). 38 */ 39 40 #include <stdio.h> 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 #include <sys/socket.h> 44 #include <sys/wait.h> 45 #include <sys/file.h> 46 47 #include <netinet/in.h> 48 49 #include <errno.h> 50 #include <pwd.h> 51 #include <signal.h> 52 #include <sgtty.h> 53 #include <stdio.h> 54 #include <netdb.h> 55 #include <syslog.h> 56 #include <strings.h> 57 58 #ifndef TIOCPKT_WINDOW 59 #define TIOCPKT_WINDOW 0x80 60 #endif 61 62 char *env[2]; 63 #define NMAX 30 64 char lusername[NMAX+1], rusername[NMAX+1]; 65 static char term[64] = "TERM="; 66 #define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation */ 67 int keepalive = 1; 68 69 #define SUPERUSER(pwd) ((pwd)->pw_uid == 0) 70 71 extern int errno; 72 int reapchild(); 73 struct passwd *getpwnam(), *pwd; 74 char *malloc(); 75 76 main(argc, argv) 77 int argc; 78 char **argv; 79 { 80 extern int opterr, optind, _check_rhosts_file; 81 int ch; 82 int on = 1, fromlen; 83 struct sockaddr_in from; 84 85 openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH); 86 87 opterr = 0; 88 while ((ch = getopt(argc, argv, "ln")) != EOF) 89 switch (ch) { 90 case 'l': 91 _check_rhosts_file = 0; 92 break; 93 case 'n': 94 keepalive = 0; 95 break; 96 case '?': 97 default: 98 syslog(LOG_ERR, "usage: rlogind [-l] [-n]"); 99 break; 100 } 101 argc -= optind; 102 argv += optind; 103 104 fromlen = sizeof (from); 105 if (getpeername(0, &from, &fromlen) < 0) { 106 syslog(LOG_ERR, "Couldn't get peer name of remote host: %m"); 107 fatalperror("Can't get peer name of host"); 108 } 109 if (keepalive && 110 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0) 111 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 112 doit(0, &from); 113 } 114 115 int child; 116 int cleanup(); 117 int netf; 118 char *line; 119 extern char *inet_ntoa(); 120 121 struct winsize win = { 0, 0, 0, 0 }; 122 123 124 doit(f, fromp) 125 int f; 126 struct sockaddr_in *fromp; 127 { 128 int i, p, t, pid, on = 1; 129 #ifndef OLD_LOGIN 130 int authenticated = 0, hostok = 0; 131 char remotehost[2 * MAXHOSTNAMELEN + 1]; 132 #endif 133 register struct hostent *hp; 134 struct hostent hostent; 135 char c; 136 137 alarm(60); 138 read(f, &c, 1); 139 if (c != 0) 140 exit(1); 141 142 alarm(0); 143 fromp->sin_port = ntohs((u_short)fromp->sin_port); 144 hp = gethostbyaddr(&fromp->sin_addr, sizeof (struct in_addr), 145 fromp->sin_family); 146 if (hp == 0) { 147 /* 148 * Only the name is used below. 149 */ 150 hp = &hostent; 151 hp->h_name = inet_ntoa(fromp->sin_addr); 152 #ifndef OLD_LOGIN 153 } else if (local_domain(hp->h_name)) { 154 /* 155 * If name returned by gethostbyaddr is in our domain, 156 * attempt to verify that we haven't been fooled by someone 157 * in a remote net; look up the name and check that this 158 * address corresponds to the name. 159 */ 160 strncpy(remotehost, hp->h_name, sizeof(remotehost) - 1); 161 remotehost[sizeof(remotehost) - 1] = 0; 162 hp = gethostbyname(remotehost); 163 if (hp) 164 for (; hp->h_addr_list[0]; hp->h_addr_list++) { 165 if (!bcmp(hp->h_addr_list[0], (caddr_t)&fromp->sin_addr, 166 sizeof(fromp->sin_addr))) { 167 hostok++; 168 break; 169 } 170 } 171 #endif 172 } 173 174 if (fromp->sin_family != AF_INET || 175 fromp->sin_port >= IPPORT_RESERVED || 176 fromp->sin_port < IPPORT_RESERVED/2) { 177 syslog(LOG_NOTICE, "Connection from %s on illegal port", 178 inet_ntoa(fromp->sin_addr)); 179 fatal(f, "Permission denied"); 180 } 181 write(f, "", 1); 182 #ifndef OLD_LOGIN 183 if (do_rlogin(hp->h_name) == 0) { 184 if (hostok) 185 authenticated++; 186 else 187 write(f, "rlogind: Host address mismatch.\r\n", 188 sizeof("rlogind: Host address mismatch.\r\n") - 1); 189 } 190 #endif 191 192 for (c = 'p'; c <= 's'; c++) { 193 struct stat stb; 194 line = "/dev/ptyXX"; 195 line[strlen("/dev/pty")] = c; 196 line[strlen("/dev/ptyp")] = '0'; 197 if (stat(line, &stb) < 0) 198 break; 199 for (i = 0; i < 16; i++) { 200 line[sizeof("/dev/ptyp") - 1] = "0123456789abcdef"[i]; 201 p = open(line, O_RDWR); 202 if (p > 0) 203 goto gotpty; 204 } 205 } 206 fatal(f, "Out of ptys"); 207 /*NOTREACHED*/ 208 gotpty: 209 (void) ioctl(p, TIOCSWINSZ, &win); 210 netf = f; 211 line[strlen("/dev/")] = 't'; 212 t = open(line, O_RDWR); 213 if (t < 0) 214 fatalperror(f, line); 215 if (fchmod(t, 0)) 216 fatalperror(f, line); 217 (void)signal(SIGHUP, SIG_IGN); 218 vhangup(); 219 (void)signal(SIGHUP, SIG_DFL); 220 t = open(line, O_RDWR); 221 if (t < 0) 222 fatalperror(f, line); 223 setup_term(t); 224 #ifdef DEBUG 225 { 226 int tt = open("/dev/tty", O_RDWR); 227 if (tt > 0) { 228 (void)ioctl(tt, TIOCNOTTY, 0); 229 (void)close(tt); 230 } 231 } 232 #endif 233 pid = fork(); 234 if (pid < 0) 235 fatalperror(f, ""); 236 if (pid == 0) { 237 close(f), close(p); 238 dup2(t, 0), dup2(t, 1), dup2(t, 2); 239 close(t); 240 #ifdef OLD_LOGIN 241 execl("/bin/login", "login", "-r", hp->h_name, 0); 242 #else /* OLD_LOGIN */ 243 if (authenticated) 244 execl("/bin/login", "login", "-p", "-h", hp->h_name, 245 "-f", lusername, 0); 246 else 247 execl("/bin/login", "login", "-p", "-h", hp->h_name, 248 lusername, 0); 249 #endif /* OLD_LOGIN */ 250 fatalperror(2, "/bin/login"); 251 /*NOTREACHED*/ 252 } 253 close(t); 254 255 ioctl(f, FIONBIO, &on); 256 ioctl(p, FIONBIO, &on); 257 ioctl(p, TIOCPKT, &on); 258 signal(SIGTSTP, SIG_IGN); 259 signal(SIGCHLD, cleanup); 260 setpgrp(0, 0); 261 protocol(f, p); 262 signal(SIGCHLD, SIG_IGN); 263 cleanup(); 264 } 265 266 char magic[2] = { 0377, 0377 }; 267 char oobdata[] = {TIOCPKT_WINDOW}; 268 269 /* 270 * Handle a "control" request (signaled by magic being present) 271 * in the data stream. For now, we are only willing to handle 272 * window size changes. 273 */ 274 control(pty, cp, n) 275 int pty; 276 char *cp; 277 int n; 278 { 279 struct winsize w; 280 281 if (n < 4+sizeof (w) || cp[2] != 's' || cp[3] != 's') 282 return (0); 283 oobdata[0] &= ~TIOCPKT_WINDOW; /* we know he heard */ 284 bcopy(cp+4, (char *)&w, sizeof(w)); 285 w.ws_row = ntohs(w.ws_row); 286 w.ws_col = ntohs(w.ws_col); 287 w.ws_xpixel = ntohs(w.ws_xpixel); 288 w.ws_ypixel = ntohs(w.ws_ypixel); 289 (void)ioctl(pty, TIOCSWINSZ, &w); 290 return (4+sizeof (w)); 291 } 292 293 /* 294 * rlogin "protocol" machine. 295 */ 296 protocol(f, p) 297 int f, p; 298 { 299 char pibuf[1024], fibuf[1024], *pbp, *fbp; 300 register pcc = 0, fcc = 0; 301 int cc, nfd, pmask, fmask; 302 char cntl; 303 304 /* 305 * Must ignore SIGTTOU, otherwise we'll stop 306 * when we try and set slave pty's window shape 307 * (our controlling tty is the master pty). 308 */ 309 (void) signal(SIGTTOU, SIG_IGN); 310 send(f, oobdata, 1, MSG_OOB); /* indicate new rlogin */ 311 if (f > p) 312 nfd = f + 1; 313 else 314 nfd = p + 1; 315 fmask = 1 << f; 316 pmask = 1 << p; 317 for (;;) { 318 int ibits, obits, ebits; 319 320 ibits = 0; 321 obits = 0; 322 if (fcc) 323 obits |= pmask; 324 else 325 ibits |= fmask; 326 if (pcc >= 0) 327 if (pcc) 328 obits |= fmask; 329 else 330 ibits |= pmask; 331 ebits = pmask; 332 if (select(nfd, &ibits, obits ? &obits : (int *)NULL, 333 &ebits, 0) < 0) { 334 if (errno == EINTR) 335 continue; 336 fatalperror(f, "select"); 337 } 338 if (ibits == 0 && obits == 0 && ebits == 0) { 339 /* shouldn't happen... */ 340 sleep(5); 341 continue; 342 } 343 #define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP)) 344 if (ebits & pmask) { 345 cc = read(p, &cntl, 1); 346 if (cc == 1 && pkcontrol(cntl)) { 347 cntl |= oobdata[0]; 348 send(f, &cntl, 1, MSG_OOB); 349 if (cntl & TIOCPKT_FLUSHWRITE) { 350 pcc = 0; 351 ibits &= ~pmask; 352 } 353 } 354 } 355 if (ibits & fmask) { 356 fcc = read(f, fibuf, sizeof(fibuf)); 357 if (fcc < 0 && errno == EWOULDBLOCK) 358 fcc = 0; 359 else { 360 register char *cp; 361 int left, n; 362 363 if (fcc <= 0) 364 break; 365 fbp = fibuf; 366 367 top: 368 for (cp = fibuf; cp < fibuf+fcc-1; cp++) 369 if (cp[0] == magic[0] && 370 cp[1] == magic[1]) { 371 left = fcc - (cp-fibuf); 372 n = control(p, cp, left); 373 if (n) { 374 left -= n; 375 if (left > 0) 376 bcopy(cp+n, cp, left); 377 fcc -= n; 378 goto top; /* n^2 */ 379 } 380 } 381 obits |= pmask; /* try write */ 382 } 383 } 384 385 if ((obits & pmask) && fcc > 0) { 386 cc = write(p, fbp, fcc); 387 if (cc > 0) { 388 fcc -= cc; 389 fbp += cc; 390 } 391 } 392 393 if (ibits & pmask) { 394 pcc = read(p, pibuf, sizeof (pibuf)); 395 pbp = pibuf; 396 if (pcc < 0 && errno == EWOULDBLOCK) 397 pcc = 0; 398 else if (pcc <= 0) 399 break; 400 else if (pibuf[0] == 0) { 401 pbp++, pcc--; 402 obits |= fmask; /* try a write */ 403 } else { 404 if (pkcontrol(pibuf[0])) { 405 pibuf[0] |= oobdata[0]; 406 send(f, &pibuf[0], 1, MSG_OOB); 407 } 408 pcc = 0; 409 } 410 } 411 if ((obits & fmask) && pcc > 0) { 412 cc = write(f, pbp, pcc); 413 if (cc < 0 && errno == EWOULDBLOCK) { 414 /* also shouldn't happen */ 415 sleep(5); 416 continue; 417 } 418 if (cc > 0) { 419 pcc -= cc; 420 pbp += cc; 421 } 422 } 423 } 424 } 425 426 cleanup() 427 { 428 char *p; 429 430 p = line + sizeof("/dev/") - 1; 431 if (logout(p)) 432 logwtmp(p, "", ""); 433 (void)chmod(line, 0666); 434 (void)chown(line, 0, 0); 435 *p = 'p'; 436 (void)chmod(line, 0666); 437 (void)chown(line, 0, 0); 438 shutdown(netf, 2); 439 exit(1); 440 } 441 442 fatal(f, msg) 443 int f; 444 char *msg; 445 { 446 char buf[BUFSIZ]; 447 448 buf[0] = '\01'; /* error indicator */ 449 (void) sprintf(buf + 1, "rlogind: %s.\r\n", msg); 450 (void) write(f, buf, strlen(buf)); 451 exit(1); 452 } 453 454 fatalperror(f, msg) 455 int f; 456 char *msg; 457 { 458 char buf[BUFSIZ]; 459 extern int sys_nerr; 460 extern char *sys_errlist[]; 461 462 if ((unsigned)errno < sys_nerr) 463 (void) sprintf(buf, "%s: %s", msg, sys_errlist[errno]); 464 else 465 (void) sprintf(buf, "%s: Error %d", msg, errno); 466 fatal(f, buf); 467 } 468 469 #ifndef OLD_LOGIN 470 do_rlogin(host) 471 char *host; 472 { 473 474 getstr(rusername, sizeof(rusername), "remuser too long"); 475 getstr(lusername, sizeof(lusername), "locuser too long"); 476 getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long"); 477 478 if (getuid()) 479 return(-1); 480 pwd = getpwnam(lusername); 481 if (pwd == NULL) 482 return(-1); 483 return(ruserok(host, SUPERUSER(pwd), rusername, lusername)); 484 } 485 486 487 getstr(buf, cnt, errmsg) 488 char *buf; 489 int cnt; 490 char *errmsg; 491 { 492 char c; 493 494 do { 495 if (read(0, &c, 1) != 1) 496 exit(1); 497 if (--cnt < 0) 498 fatal(1, errmsg); 499 *buf++ = c; 500 } while (c != 0); 501 } 502 503 extern char **environ; 504 505 char *speeds[] = { 506 "0", "50", "75", "110", "134", "150", "200", "300", "600", 507 "1200", "1800", "2400", "4800", "9600", "19200", "38400", 508 }; 509 #define NSPEEDS (sizeof(speeds) / sizeof(speeds[0])) 510 511 setup_term(fd) 512 int fd; 513 { 514 register char *cp = index(term, '/'), **cpp; 515 struct sgttyb sgttyb; 516 char *speed; 517 518 (void)ioctl(fd, TIOCGETP, &sgttyb); 519 if (cp) { 520 *cp++ = '\0'; 521 speed = cp; 522 cp = index(speed, '/'); 523 if (cp) 524 *cp++ = '\0'; 525 for (cpp = speeds; cpp < &speeds[NSPEEDS]; cpp++) 526 if (strcmp(*cpp, speed) == 0) { 527 sgttyb.sg_ispeed = sgttyb.sg_ospeed = cpp - speeds; 528 break; 529 } 530 } 531 sgttyb.sg_flags = ECHO|CRMOD|ANYP|XTABS; 532 (void)ioctl(fd, TIOCSETP, &sgttyb); 533 534 env[0] = term; 535 env[1] = 0; 536 environ = env; 537 } 538 539 /* 540 * Check whether host h is in our local domain, 541 * as determined by the part of the name following 542 * the first '.' in its name and in ours. 543 * If either name is unqualified (contains no '.'), 544 * assume that the host is local, as it will be 545 * interpreted as such. 546 */ 547 local_domain(h) 548 char *h; 549 { 550 char localhost[MAXHOSTNAMELEN]; 551 char *p1, *p2 = index(h, '.'); 552 553 (void) gethostname(localhost, sizeof(localhost)); 554 p1 = index(localhost, '.'); 555 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 556 return(1); 557 return(0); 558 } 559 #endif /* OLD_LOGIN */ 560