2 * Copyright (c) 1988, 1989, 1992, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
33 * @(#) Copyright (c) 1988, 1989, 1992, 1993, 1994 The Regents of the University of California. All rights reserved.
34 * @(#)rshd.c 8.2 (Berkeley) 4/6/94
35 * $FreeBSD: src/libexec/rshd/rshd.c,v 1.30.2.5 2002/05/14 22:27:21 des Exp $
36 * $DragonFly: src/libexec/rshd/rshd.c,v 1.5 2007/05/18 17:05:12 dillon Exp $
40 * remote shell server:
47 #include <sys/param.h>
48 #include <sys/ioctl.h>
50 #include <sys/socket.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/in.h>
54 #include <netinet/ip.h>
55 #include <netinet/tcp.h>
56 #include <arpa/inet.h>
72 #include <login_cap.h>
75 /* wrapper for KAME-special getnameinfo() */
76 #ifndef NI_WITHSCOPEID
77 #define NI_WITHSCOPEID 0
80 extern int __check_rhosts_file;
81 extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */
84 int log_success; /* If TRUE, log all successful accesses */
97 struct sockaddr_in su_sin;
98 struct sockaddr_in6 su_sin6;
100 #define su_len su_si.si_len
101 #define su_family su_si.si_family
102 #define su_port su_si.si_port
104 void doit(union sockunion *);
105 void error(const char *, ...);
106 void getstr(char *, int, const char *);
107 int local_domain(char *);
108 char *topdomain(char *);
112 char bshell[] = _PATH_BSHELL;
114 #define OPTIONS "alnDL"
117 main(int argc, char *argv[])
119 struct linger linger;
122 struct sockaddr_storage from;
124 openlog("rshd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
127 while ((ch = getopt(argc, argv, OPTIONS)) != -1)
130 /* ignored for compatibility */
133 __check_rhosts_file = 0;
160 syslog(LOG_ERR, "-k is required for -x");
165 fromlen = sizeof (from);
166 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
167 syslog(LOG_ERR, "getpeername: %m");
171 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on,
173 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
175 linger.l_linger = 60; /* XXX */
176 if (setsockopt(0, SOL_SOCKET, SO_LINGER, (char *)&linger,
177 sizeof (linger)) < 0)
178 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
180 setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0)
181 syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m");
182 doit((union sockunion *)&from);
187 char username[20] = "USER=";
188 char homedir[64] = "HOME=";
189 char shell[64] = "SHELL=";
190 char path[100] = "PATH=";
192 {homedir, shell, path, username, 0};
196 doit(union sockunion *fromp)
200 fd_set ready, readfrom;
201 int cc, nfd, pv[2], pid, s;
203 const char *errorstr;
204 char *cp, sig, buf[BUFSIZ];
205 char cmdbuf[NCARGS+1], locuser[16], remuser[16];
206 char fromhost[2 * MAXHOSTNAMELEN + 1];
207 char numericname[INET6_ADDRSTRLEN];
208 int af = fromp->su_family, err;
217 signal(SIGINT, SIG_DFL);
218 signal(SIGQUIT, SIG_DFL);
219 signal(SIGTERM, SIG_DFL);
220 fromp->su_port = ntohs((u_short)fromp->su_port);
226 syslog(LOG_ERR, "malformed \"from\" address (af %d)\n", af);
229 err = getnameinfo((struct sockaddr *)fromp, fromp->su_len, numericname,
230 sizeof(numericname), NULL, 0,
231 NI_NUMERICHOST|NI_WITHSCOPEID);
232 /* XXX: do 'err' check */
235 u_char optbuf[BUFSIZ/3];
236 socklen_t optsize = sizeof(optbuf), i;
240 if ((ip = getprotobyname("ip")) != NULL)
241 ipproto = ip->p_proto;
243 ipproto = IPPROTO_IP;
244 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) &&
246 for (i = 0; i < optsize; ) {
247 u_char c = optbuf[i];
248 if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
250 "connection refused from %s with IP option %s",
252 c == IPOPT_LSRR ? "LSRR" : "SSRR");
257 i += (c == IPOPT_NOP) ? 1 : optbuf[i+1];
263 if (fromp->su_port >= IPPORT_RESERVED ||
264 fromp->su_port < IPPORT_RESERVED/2) {
265 syslog(LOG_NOTICE|LOG_AUTH,
266 "connection from %s on illegal port %u",
274 s = 0; /* not set or used if port == 0 */
277 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) {
279 syslog(LOG_NOTICE, "read: %m");
280 shutdown(0, SHUT_RDWR);
285 port = port * 10 + c - '0';
290 int lport = IPPORT_RESERVED - 1;
291 s = rresvport_af(&lport, af);
293 syslog(LOG_ERR, "can't get stderr port: %m");
296 if (port >= IPPORT_RESERVED ||
297 port < IPPORT_RESERVED/2) {
298 syslog(LOG_NOTICE|LOG_AUTH,
299 "2nd socket from %s on unreserved port %u",
304 fromp->su_port = htons(port);
305 if (connect(s, (struct sockaddr *)fromp, fromp->su_len) < 0) {
306 syslog(LOG_INFO, "connect second port %d: %m", port);
312 realhostname_sa(fromhost, sizeof(fromhost) - 1,
313 (struct sockaddr *)fromp,
315 fromhost[sizeof(fromhost) - 1] = '\0';
318 if (doencrypt && af == AF_INET) {
319 struct sockaddr_in local_addr;
320 rc = sizeof(local_addr);
321 if (getsockname(0, (struct sockaddr *)&local_addr,
323 syslog(LOG_ERR, "getsockname: %m");
324 error("rlogind: getsockname: %m");
327 authopts = KOPT_DO_MUTUAL;
328 rc = krb_recvauth(authopts, 0, ticket,
329 "rcmd", instance, &fromaddr,
330 &local_addr, kdata, "", schedule,
332 des_set_key(&kdata->session, schedule);
336 getstr(remuser, sizeof(remuser), "remuser");
337 getstr(locuser, sizeof(locuser), "locuser");
338 getstr(cmdbuf, sizeof(cmdbuf), "command");
341 pwd = getpwnam(locuser);
343 syslog(LOG_INFO|LOG_AUTH,
344 "%s@%s as %s: unknown login. cmd='%.80s'",
345 remuser, fromhost, locuser, cmdbuf);
346 if (errorstr == NULL)
347 errorstr = "Login incorrect.\n";
351 lc = login_getpwclass(pwd);
353 if (chdir(pwd->pw_dir) < 0) {
355 if (chdir("/") < 0 ||
356 login_getcapbool(lc, "requirehome", !!pwd->pw_uid)) {
357 syslog(LOG_INFO|LOG_AUTH,
358 "%s@%s as %s: no home directory. cmd='%.80s'",
359 remuser, fromhost, locuser, cmdbuf);
360 error("No remote home directory.\n");
366 syslog(LOG_INFO|LOG_AUTH,
367 "%s@%s as %s: no home directory. cmd='%.80s'",
368 remuser, fromhost, locuser, cmdbuf);
369 error("No remote directory.\n");
377 (pwd->pw_expire && time(NULL) >= pwd->pw_expire) ||
378 iruserok_sa(fromp, fromp->su_len, pwd->pw_uid == 0,
379 remuser, locuser) < 0) {
381 syslog(LOG_INFO|LOG_AUTH,
382 "%s@%s as %s: permission denied (%s). cmd='%.80s'",
383 remuser, fromhost, locuser, __rcmd_errstr,
386 syslog(LOG_INFO|LOG_AUTH,
387 "%s@%s as %s: permission denied. cmd='%.80s'",
388 remuser, fromhost, locuser, cmdbuf);
391 if (errorstr == NULL)
392 errorstr = "Login incorrect.\n";
393 error(errorstr, fromhost);
397 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) {
398 error("Logins currently disabled.\n");
402 if (lc != NULL && fromp->su_family == AF_INET) { /*XXX*/
403 char remote_ip[MAXHOSTNAMELEN];
405 strncpy(remote_ip, numericname,
406 sizeof(remote_ip) - 1);
407 remote_ip[sizeof(remote_ip) - 1] = 0;
408 if (!auth_hostok(lc, fromhost, remote_ip)) {
409 syslog(LOG_INFO|LOG_AUTH,
410 "%s@%s as %s: permission denied (%s). cmd='%.80s'",
411 remuser, fromhost, locuser, __rcmd_errstr,
413 error("Login incorrect.\n");
416 if (!auth_timeok(lc, time(NULL))) {
417 error("Logins not available right now\n");
421 #endif /* !LOGIN_CAP */
423 /* before fork, while we're session leader */
424 if (setlogin(pwd->pw_name) < 0)
425 syslog(LOG_ERR, "setlogin() failed: %m");
428 write(STDERR_FILENO, "\0", 1);
433 error("Can't make pipe.\n");
439 error("Can't make 2nd pipe.\n");
443 error("Can't make 3rd pipe.\n");
450 error("Can't fork; try again.\n");
456 static char msg[] = SECURE_MESSAGE;
459 des_enc_write(s, msg, sizeof(msg) - 1,
460 schedule, &kdata->session);
472 FD_SET(s, &readfrom);
473 FD_SET(pv[0], &readfrom);
481 FD_SET(pv2[0], &writeto);
482 FD_SET(pv1[0], &readfrom);
484 nfd = MAX(nfd, pv2[0]);
485 nfd = MAX(nfd, pv1[0]);
488 ioctl(pv[0], FIONBIO, (char *)&one);
490 /* should set s nbio! */
497 if (select(nfd, &ready,
498 &wready, (fd_set *) 0,
499 (struct timeval *) 0) < 0)
503 if (select(nfd, &ready, NULL,
506 if (FD_ISSET(s, &ready)) {
510 ret = des_enc_read(s, &sig, 1,
511 schedule, &kdata->session);
514 ret = read(s, &sig, 1);
516 FD_CLR(s, &readfrom);
520 if (FD_ISSET(pv[0], &ready)) {
522 cc = read(pv[0], buf, sizeof(buf));
524 shutdown(s, SHUT_RDWR);
525 FD_CLR(pv[0], &readfrom);
529 des_enc_write(s, buf,
538 if (doencrypt && FD_ISSET(pv1[0], &ready)) {
540 cc = read(pv1[0], buf, sizeof(buf));
542 shutdown(pv1[0], SHUT_RDWR);
543 FD_CLR(pv1[0], &readfrom);
545 des_enc_write(STDOUT_FILENO,
551 if (doencrypt && FD_ISSET(pv2[0], &wready)) {
553 cc = des_enc_read(STDIN_FILENO,
555 schedule, &kdata->session);
557 shutdown(pv2[0], SHUT_RDWR);
558 FD_CLR(pv2[0], &writeto);
560 write(pv2[0], buf, cc);
565 } while (FD_ISSET(s, &readfrom) ||
567 (doencrypt && FD_ISSET(pv1[0], &readfrom)) ||
569 FD_ISSET(pv[0], &readfrom));
572 setpgrp(0, getpid());
577 close(pv1[0]); close(pv2[0]);
587 if (*pwd->pw_shell == '\0')
588 pwd->pw_shell = bshell;
590 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
591 strcat(path, _PATH_DEFPATH);
592 strncat(shell, pwd->pw_shell, sizeof(shell)-7);
593 strncat(username, pwd->pw_name, sizeof(username)-6);
594 cp = strrchr(pwd->pw_shell, '/');
600 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETALL) != 0) {
601 syslog(LOG_ERR, "setusercontext: %m");
606 setgid((gid_t)pwd->pw_gid);
607 initgroups(pwd->pw_name, pwd->pw_gid);
608 setuid((uid_t)pwd->pw_uid);
611 if (log_success || pwd->pw_uid == 0) {
612 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'",
613 remuser, fromhost, locuser, cmdbuf);
615 execl(pwd->pw_shell, cp, "-c", cmdbuf, (char *)NULL);
616 perror(pwd->pw_shell);
621 * Report error to client. Note: can't be used until second socket has
622 * connected to client, or older clients will hang waiting for that
627 error(const char *fmt, ...)
631 char *bp, buf[BUFSIZ];
634 if (sent_null == 0) {
639 vsnprintf(bp, sizeof(buf) - 1, fmt, ap);
640 write(STDERR_FILENO, buf, len + strlen(bp));
644 getstr(char *buf, int cnt, const char *err)
649 if (read(STDIN_FILENO, &c, 1) != 1)
653 error("%s too long\n", err);
660 * Check whether host h is in our local domain,
661 * defined as sharing the last two components of the domain part,
662 * or the entire domain part if the local domain has only one component.
663 * If either name is unqualified (contains no '.'),
664 * assume that the host is local, as it will be
665 * interpreted as such.
668 local_domain(char *h)
670 char localhost[MAXHOSTNAMELEN];
674 gethostname(localhost, sizeof(localhost) - 1);
675 localhost[sizeof(localhost) - 1] = '\0';
676 p1 = topdomain(localhost);
678 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2))
686 char *p, *maybe = NULL;
689 for (p = h + strlen(h); p >= h; p--) {
703 syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS);