rlogind.c revision 1.8
1 /*- 2 * Copyright (c) 1983, 1988, 1989, 1993 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 #ifndef lint 35 static char copyright[] = 36 "@(#) Copyright (c) 1983, 1988, 1989, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 /* from: static char sccsid[] = "@(#)rlogind.c 8.1 (Berkeley) 6/4/93"; */ 42 static char *rcsid = "$Id: rlogind.c,v 1.8 1996/05/21 12:22:31 mrg Exp $"; 43 #endif /* not lint */ 44 45 /* 46 * remote login server: 47 * \0 48 * remuser\0 49 * locuser\0 50 * terminal_type/speed\0 51 * data 52 */ 53 54 #define FD_SETSIZE 16 /* don't need many bits for select */ 55 #include <sys/param.h> 56 #include <sys/stat.h> 57 #include <sys/ioctl.h> 58 #include <signal.h> 59 #include <termios.h> 60 61 #include <sys/socket.h> 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #include <arpa/inet.h> 66 #include <netdb.h> 67 68 #include <pwd.h> 69 #include <syslog.h> 70 #include <errno.h> 71 #include <stdio.h> 72 #include <unistd.h> 73 #include <stdlib.h> 74 #include <string.h> 75 #include <utmp.h> 76 #include "pathnames.h" 77 78 #ifndef TIOCPKT_WINDOW 79 #define TIOCPKT_WINDOW 0x80 80 #endif 81 82 #define ARGSTR "aln" 83 84 char *env[2]; 85 #define NMAX 30 86 char lusername[NMAX+1], rusername[NMAX+1]; 87 static char term[64] = "TERM="; 88 #define ENVSIZE (sizeof("TERM=")-1) /* skip null for concatenation */ 89 int keepalive = 1; 90 int check_all = 0; 91 92 struct passwd *pwd; 93 94 void doit __P((int, struct sockaddr_in *)); 95 int control __P((int, char *, int)); 96 void protocol __P((int, int)); 97 void cleanup __P((int)); 98 void fatal __P((int, char *, int)); 99 int do_rlogin __P((struct sockaddr_in *)); 100 void getstr __P((char *, int, char *)); 101 void setup_term __P((int)); 102 int do_krb_login __P((struct sockaddr_in *)); 103 void usage __P((void)); 104 int local_domain __P((char *)); 105 char *topdomain __P((char *)); 106 107 int 108 main(argc, argv) 109 int argc; 110 char *argv[]; 111 { 112 extern int __check_rhosts_file; 113 struct sockaddr_in from; 114 int ch, fromlen, on; 115 116 openlog("rlogind", LOG_PID | LOG_CONS, LOG_AUTH); 117 118 opterr = 0; 119 while ((ch = getopt(argc, argv, ARGSTR)) != EOF) 120 switch (ch) { 121 case 'a': 122 check_all = 1; 123 break; 124 case 'l': 125 __check_rhosts_file = 0; 126 break; 127 case 'n': 128 keepalive = 0; 129 break; 130 case '?': 131 default: 132 usage(); 133 break; 134 } 135 argc -= optind; 136 argv += optind; 137 138 fromlen = sizeof (from); 139 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { 140 syslog(LOG_ERR,"Can't get peer name of remote host: %m"); 141 fatal(STDERR_FILENO, "Can't get peer name of remote host", 1); 142 } 143 on = 1; 144 if (keepalive && 145 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof (on)) < 0) 146 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 147 on = IPTOS_LOWDELAY; 148 if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0) 149 syslog(LOG_WARNING, "setsockopt (IP_TOS): %m"); 150 doit(0, &from); 151 } 152 153 int child; 154 int netf; 155 char line[MAXPATHLEN]; 156 int confirmed; 157 158 struct winsize win = { 0, 0, 0, 0 }; 159 160 161 void 162 doit(f, fromp) 163 int f; 164 struct sockaddr_in *fromp; 165 { 166 int master, pid, on = 1; 167 int authenticated = 0; 168 register struct hostent *hp; 169 char hostname[2 * MAXHOSTNAMELEN + 1]; 170 char c; 171 172 alarm(60); 173 read(f, &c, 1); 174 175 if (c != 0) 176 exit(1); 177 178 alarm(0); 179 fromp->sin_port = ntohs((u_short)fromp->sin_port); 180 hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(struct in_addr), 181 fromp->sin_family); 182 if (hp && (strlen(hp->h_name) <= UT_HOSTSIZE)) 183 (void)strcpy(hostname, hp->h_name); 184 else 185 (void)strcpy(hostname, inet_ntoa(fromp->sin_addr)); 186 187 { 188 if (fromp->sin_family != AF_INET || 189 fromp->sin_port >= IPPORT_RESERVED || 190 fromp->sin_port < IPPORT_RESERVED/2) { 191 syslog(LOG_NOTICE, "Connection from %s on illegal port", 192 inet_ntoa(fromp->sin_addr)); 193 fatal(f, "Permission denied", 0); 194 } 195 #ifdef IP_OPTIONS 196 { 197 u_char optbuf[BUFSIZ/3], *cp; 198 char lbuf[BUFSIZ], *lp; 199 int optsize = sizeof(optbuf), ipproto; 200 struct protoent *ip; 201 202 if ((ip = getprotobyname("ip")) != NULL) 203 ipproto = ip->p_proto; 204 else 205 ipproto = IPPROTO_IP; 206 if (getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, 207 &optsize) == 0 && optsize != 0) { 208 lp = lbuf; 209 for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3) 210 sprintf(lp, " %2.2x", *cp); 211 syslog(LOG_NOTICE, 212 "Connection received using IP options (ignored):%s", 213 lbuf); 214 if (setsockopt(0, ipproto, IP_OPTIONS, 215 (char *)NULL, optsize) != 0) { 216 syslog(LOG_ERR, 217 "setsockopt IP_OPTIONS NULL: %m"); 218 exit(1); 219 } 220 } 221 } 222 #endif 223 if (do_rlogin(fromp) == 0) 224 authenticated++; 225 } 226 if (confirmed == 0) { 227 write(f, "", 1); 228 confirmed = 1; /* we sent the null! */ 229 } 230 netf = f; 231 232 pid = forkpty(&master, line, NULL, &win); 233 if (pid < 0) { 234 if (errno == ENOENT) 235 fatal(f, "Out of ptys", 0); 236 else 237 fatal(f, "Forkpty", 1); 238 } 239 if (pid == 0) { 240 if (f > 2) /* f should always be 0, but... */ 241 (void) close(f); 242 setup_term(0); 243 if (authenticated) 244 execl(_PATH_LOGIN, "login", "-p", 245 "-h", hostname, "-f", "--", lusername, (char *)0); 246 else 247 execl(_PATH_LOGIN, "login", "-p", 248 "-h", hostname, "--", lusername, (char *)0); 249 fatal(STDERR_FILENO, _PATH_LOGIN, 1); 250 /*NOTREACHED*/ 251 } 252 ioctl(f, FIONBIO, &on); 253 ioctl(master, FIONBIO, &on); 254 ioctl(master, TIOCPKT, &on); 255 signal(SIGCHLD, cleanup); 256 protocol(f, master); 257 signal(SIGCHLD, SIG_IGN); 258 cleanup(0); 259 } 260 261 char magic[2] = { 0377, 0377 }; 262 char oobdata[] = {TIOCPKT_WINDOW}; 263 264 /* 265 * Handle a "control" request (signaled by magic being present) 266 * in the data stream. For now, we are only willing to handle 267 * window size changes. 268 */ 269 int 270 control(pty, cp, n) 271 int pty; 272 char *cp; 273 int n; 274 { 275 struct winsize w; 276 277 if (n < 4+sizeof (w) || cp[2] != 's' || cp[3] != 's') 278 return (0); 279 oobdata[0] &= ~TIOCPKT_WINDOW; /* we know he heard */ 280 bcopy(cp+4, (char *)&w, sizeof(w)); 281 w.ws_row = ntohs(w.ws_row); 282 w.ws_col = ntohs(w.ws_col); 283 w.ws_xpixel = ntohs(w.ws_xpixel); 284 w.ws_ypixel = ntohs(w.ws_ypixel); 285 (void)ioctl(pty, TIOCSWINSZ, &w); 286 return (4+sizeof (w)); 287 } 288 289 /* 290 * rlogin "protocol" machine. 291 */ 292 void 293 protocol(f, p) 294 register int f, p; 295 { 296 char pibuf[1024+1], fibuf[1024], *pbp, *fbp; 297 register pcc = 0, fcc = 0; 298 int cc, nfd, n; 299 char cntl; 300 301 /* 302 * Must ignore SIGTTOU, otherwise we'll stop 303 * when we try and set slave pty's window shape 304 * (our controlling tty is the master pty). 305 */ 306 (void) signal(SIGTTOU, SIG_IGN); 307 send(f, oobdata, 1, MSG_OOB); /* indicate new rlogin */ 308 if (f > p) 309 nfd = f + 1; 310 else 311 nfd = p + 1; 312 if (nfd > FD_SETSIZE) { 313 syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE"); 314 fatal(f, "internal error (select mask too small)", 0); 315 } 316 for (;;) { 317 fd_set ibits, obits, ebits, *omask; 318 319 FD_ZERO(&ebits); 320 FD_ZERO(&ibits); 321 FD_ZERO(&obits); 322 omask = (fd_set *)NULL; 323 if (fcc) { 324 FD_SET(p, &obits); 325 omask = &obits; 326 } else 327 FD_SET(f, &ibits); 328 if (pcc >= 0) 329 if (pcc) { 330 FD_SET(f, &obits); 331 omask = &obits; 332 } else 333 FD_SET(p, &ibits); 334 FD_SET(p, &ebits); 335 if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) { 336 if (errno == EINTR) 337 continue; 338 fatal(f, "select", 1); 339 } 340 if (n == 0) { 341 /* shouldn't happen... */ 342 sleep(5); 343 continue; 344 } 345 #define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP)) 346 if (FD_ISSET(p, &ebits)) { 347 cc = read(p, &cntl, 1); 348 if (cc == 1 && pkcontrol(cntl)) { 349 cntl |= oobdata[0]; 350 send(f, &cntl, 1, MSG_OOB); 351 if (cntl & TIOCPKT_FLUSHWRITE) { 352 pcc = 0; 353 FD_CLR(p, &ibits); 354 } 355 } 356 } 357 if (FD_ISSET(f, &ibits)) { 358 fcc = read(f, fibuf, sizeof(fibuf)); 359 if (fcc < 0 && errno == EWOULDBLOCK) 360 fcc = 0; 361 else { 362 register char *cp; 363 int left, n; 364 365 if (fcc <= 0) 366 break; 367 fbp = fibuf; 368 369 top: 370 for (cp = fibuf; cp < fibuf+fcc-1; cp++) 371 if (cp[0] == magic[0] && 372 cp[1] == magic[1]) { 373 left = fcc - (cp-fibuf); 374 n = control(p, cp, left); 375 if (n) { 376 left -= n; 377 if (left > 0) 378 bcopy(cp+n, cp, left); 379 fcc -= n; 380 goto top; /* n^2 */ 381 } 382 } 383 FD_SET(p, &obits); /* try write */ 384 } 385 } 386 387 if (FD_ISSET(p, &obits) && fcc > 0) { 388 cc = write(p, fbp, fcc); 389 if (cc > 0) { 390 fcc -= cc; 391 fbp += cc; 392 } 393 } 394 395 if (FD_ISSET(p, &ibits)) { 396 pcc = read(p, pibuf, sizeof (pibuf)); 397 pbp = pibuf; 398 if (pcc < 0 && errno == EWOULDBLOCK) 399 pcc = 0; 400 else if (pcc <= 0) 401 break; 402 else if (pibuf[0] == 0) { 403 pbp++, pcc--; 404 FD_SET(f, &obits); /* try write */ 405 } else { 406 if (pkcontrol(pibuf[0])) { 407 pibuf[0] |= oobdata[0]; 408 send(f, &pibuf[0], 1, MSG_OOB); 409 } 410 pcc = 0; 411 } 412 } 413 if ((FD_ISSET(f, &obits)) && pcc > 0) { 414 cc = write(f, pbp, pcc); 415 if (cc < 0 && errno == EWOULDBLOCK) { 416 /* 417 * This happens when we try write after read 418 * from p, but some old kernels balk at large 419 * writes even when select returns true. 420 */ 421 if (!FD_ISSET(p, &ibits)) 422 sleep(5); 423 continue; 424 } 425 if (cc > 0) { 426 pcc -= cc; 427 pbp += cc; 428 } 429 } 430 } 431 } 432 433 void 434 cleanup(signo) 435 int signo; 436 { 437 char *p; 438 439 p = line + sizeof(_PATH_DEV) - 1; 440 if (logout(p)) 441 logwtmp(p, "", ""); 442 (void)chmod(line, 0666); 443 (void)chown(line, 0, 0); 444 *p = 'p'; 445 (void)chmod(line, 0666); 446 (void)chown(line, 0, 0); 447 shutdown(netf, 2); 448 exit(1); 449 } 450 451 void 452 fatal(f, msg, syserr) 453 int f; 454 char *msg; 455 int syserr; 456 { 457 int len; 458 char buf[BUFSIZ], *bp = buf; 459 460 /* 461 * Prepend binary one to message if we haven't sent 462 * the magic null as confirmation. 463 */ 464 if (!confirmed) 465 *bp++ = '\01'; /* error indicator */ 466 if (syserr) 467 len = sprintf(bp, "rlogind: %s: %s.\r\n", 468 msg, strerror(errno)); 469 else 470 len = sprintf(bp, "rlogind: %s.\r\n", msg); 471 (void) write(f, buf, bp + len - buf); 472 exit(1); 473 } 474 475 int 476 do_rlogin(dest) 477 struct sockaddr_in *dest; 478 { 479 getstr(rusername, sizeof(rusername), "remuser too long"); 480 getstr(lusername, sizeof(lusername), "locuser too long"); 481 getstr(term+ENVSIZE, sizeof(term)-ENVSIZE, "Terminal type too long"); 482 483 pwd = getpwnam(lusername); 484 if (pwd == NULL) 485 return (-1); 486 if (pwd->pw_uid == 0) 487 return (-1); 488 /* XXX why don't we syslog() failure? */ 489 return (iruserok(dest->sin_addr.s_addr, 0, rusername, lusername)); 490 } 491 492 void 493 getstr(buf, cnt, errmsg) 494 char *buf; 495 int cnt; 496 char *errmsg; 497 { 498 char c; 499 500 do { 501 if (read(0, &c, 1) != 1) 502 exit(1); 503 if (--cnt < 0) 504 fatal(STDOUT_FILENO, errmsg, 0); 505 *buf++ = c; 506 } while (c != 0); 507 } 508 509 extern char **environ; 510 511 void 512 setup_term(fd) 513 int fd; 514 { 515 register char *cp = index(term+ENVSIZE, '/'); 516 char *speed; 517 struct termios tt; 518 519 #ifndef notyet 520 tcgetattr(fd, &tt); 521 if (cp) { 522 *cp++ = '\0'; 523 speed = cp; 524 cp = index(speed, '/'); 525 if (cp) 526 *cp++ = '\0'; 527 cfsetspeed(&tt, atoi(speed)); 528 } 529 530 tt.c_iflag = TTYDEF_IFLAG; 531 tt.c_oflag = TTYDEF_OFLAG; 532 tt.c_lflag = TTYDEF_LFLAG; 533 tcsetattr(fd, TCSAFLUSH, &tt); 534 #else 535 if (cp) { 536 *cp++ = '\0'; 537 speed = cp; 538 cp = index(speed, '/'); 539 if (cp) 540 *cp++ = '\0'; 541 tcgetattr(fd, &tt); 542 cfsetspeed(&tt, atoi(speed)); 543 tcsetattr(fd, TCSAFLUSH, &tt); 544 } 545 #endif 546 547 env[0] = term; 548 env[1] = 0; 549 environ = env; 550 } 551 552 553 void 554 usage() 555 { 556 syslog(LOG_ERR, "usage: rlogind [-aln]"); 557 } 558 559 /* 560 * Check whether host h is in our local domain, 561 * defined as sharing the last two components of the domain part, 562 * or the entire domain part if the local domain has only one component. 563 * If either name is unqualified (contains no '.'), 564 * assume that the host is local, as it will be 565 * interpreted as such. 566 */ 567 int 568 local_domain(h) 569 char *h; 570 { 571 char localhost[MAXHOSTNAMELEN]; 572 char *p1, *p2; 573 574 localhost[0] = 0; 575 (void) gethostname(localhost, sizeof(localhost)); 576 p1 = topdomain(localhost); 577 p2 = topdomain(h); 578 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 579 return (1); 580 return (0); 581 } 582 583 char * 584 topdomain(h) 585 char *h; 586 { 587 register char *p; 588 char *maybe = NULL; 589 int dots = 0; 590 591 for (p = h + strlen(h); p >= h; p--) { 592 if (*p == '.') { 593 if (++dots == 2) 594 return (p); 595 maybe = p; 596 } 597 } 598 return (maybe); 599 } 600
Indexes created Tue Sep 23 07:09:52 GMT 2025