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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#) Copyright (c) 1988, 1989, 1992, 1993, 1994 The Regents of the University of California. All rights reserved.
30 * @(#)rshd.c 8.2 (Berkeley) 4/6/94
31 * $FreeBSD: src/libexec/rshd/rshd.c,v 1.30.2.5 2002/05/14 22:27:21 des Exp $
35 * remote shell server:
42 #include <sys/param.h>
43 #include <sys/ioctl.h>
45 #include <sys/socket.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/in.h>
49 #include <netinet/ip.h>
50 #include <netinet/tcp.h>
51 #include <arpa/inet.h>
67 #include <login_cap.h>
70 /* wrapper for KAME-special getnameinfo() */
71 #ifndef NI_WITHSCOPEID
72 #define NI_WITHSCOPEID 0
75 extern int __check_rhosts_file;
76 extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */
79 int log_success; /* If TRUE, log all successful accesses */
92 struct sockaddr_in su_sin;
93 struct sockaddr_in6 su_sin6;
95 #define su_len su_si.si_len
96 #define su_family su_si.si_family
97 #define su_port su_si.si_port
99 void doit(union sockunion *);
100 void error(const char *, ...) __printflike(1, 2);
101 void getstr(char *, int, const char *);
102 int local_domain(char *);
103 char *topdomain(char *);
107 char bshell[] = _PATH_BSHELL;
109 #define OPTIONS "alnDL"
112 main(int argc, char *argv[])
114 struct linger linger;
117 struct sockaddr_storage from;
119 openlog("rshd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
122 while ((ch = getopt(argc, argv, OPTIONS)) != -1)
125 /* ignored for compatibility */
128 __check_rhosts_file = 0;
155 syslog(LOG_ERR, "-k is required for -x");
160 fromlen = sizeof (from);
161 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
162 syslog(LOG_ERR, "getpeername: %m");
166 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on,
168 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
170 linger.l_linger = 60; /* XXX */
171 if (setsockopt(0, SOL_SOCKET, SO_LINGER, (char *)&linger,
172 sizeof (linger)) < 0)
173 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
175 setsockopt(0, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) < 0)
176 syslog(LOG_WARNING, "setsockopt (TCP_NODELAY): %m");
177 doit((union sockunion *)&from);
182 char username[20] = "USER=";
183 char homedir[64] = "HOME=";
184 char shell[64] = "SHELL=";
185 char path[100] = "PATH=";
187 {homedir, shell, path, username, 0};
191 doit(union sockunion *fromp)
195 fd_set ready, readfrom;
196 int cc, nfd, pv[2], pid, s;
198 const char *errorstr;
199 char *cp, sig, buf[BUFSIZ];
200 char cmdbuf[NCARGS+1], locuser[16], remuser[16];
201 char fromhost[2 * MAXHOSTNAMELEN + 1];
202 char numericname[INET6_ADDRSTRLEN];
203 int af = fromp->su_family, gaierror;
212 signal(SIGINT, SIG_DFL);
213 signal(SIGQUIT, SIG_DFL);
214 signal(SIGTERM, SIG_DFL);
215 fromp->su_port = ntohs((u_short)fromp->su_port);
221 syslog(LOG_ERR, "malformed \"from\" address (af %d)\n", af);
224 gaierror = getnameinfo((struct sockaddr *)fromp, fromp->su_len,
225 numericname, sizeof(numericname), NULL, 0,
226 NI_NUMERICHOST|NI_WITHSCOPEID);
228 syslog(LOG_ERR, "malformed \"from\" address (af %d): %s", af,
229 gai_strerror(gaierror));
234 u_char optbuf[BUFSIZ/3];
235 socklen_t optsize = sizeof(optbuf), i;
239 if ((ip = getprotobyname("ip")) != NULL)
240 ipproto = ip->p_proto;
242 ipproto = IPPROTO_IP;
243 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) &&
245 for (i = 0; i < optsize; ) {
246 u_char c = optbuf[i];
247 if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
249 "connection refused from %s with IP option %s",
251 c == IPOPT_LSRR ? "LSRR" : "SSRR");
256 i += (c == IPOPT_NOP) ? 1 : optbuf[i+1];
262 if (fromp->su_port >= IPPORT_RESERVED ||
263 fromp->su_port < IPPORT_RESERVED/2) {
264 syslog(LOG_NOTICE|LOG_AUTH,
265 "connection from %s on illegal port %u",
273 s = 0; /* not set or used if port == 0 */
276 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) {
278 syslog(LOG_NOTICE, "read: %m");
279 shutdown(0, SHUT_RDWR);
284 port = port * 10 + c - '0';
289 int lport = IPPORT_RESERVED - 1;
290 s = rresvport_af(&lport, af);
292 syslog(LOG_ERR, "can't get stderr port: %m");
295 if (port >= IPPORT_RESERVED ||
296 port < IPPORT_RESERVED/2) {
297 syslog(LOG_NOTICE|LOG_AUTH,
298 "2nd socket from %s on unreserved port %u",
303 fromp->su_port = htons(port);
304 if (connect(s, (struct sockaddr *)fromp, fromp->su_len) < 0) {
305 syslog(LOG_INFO, "connect second port %d: %m", port);
311 realhostname_sa(fromhost, sizeof(fromhost) - 1,
312 (struct sockaddr *)fromp,
314 fromhost[sizeof(fromhost) - 1] = '\0';
317 if (doencrypt && af == AF_INET) {
318 struct sockaddr_in local_addr;
319 rc = sizeof(local_addr);
320 if (getsockname(0, (struct sockaddr *)&local_addr,
322 syslog(LOG_ERR, "getsockname: %m");
323 error("rlogind: getsockname: %m");
326 authopts = KOPT_DO_MUTUAL;
327 rc = krb_recvauth(authopts, 0, ticket,
328 "rcmd", instance, &fromaddr,
329 &local_addr, kdata, "", schedule,
331 des_set_key(&kdata->session, schedule);
335 getstr(remuser, sizeof(remuser), "remuser");
336 getstr(locuser, sizeof(locuser), "locuser");
337 getstr(cmdbuf, sizeof(cmdbuf), "command");
340 pwd = getpwnam(locuser);
342 syslog(LOG_INFO|LOG_AUTH,
343 "%s@%s as %s: unknown login. cmd='%.80s'",
344 remuser, fromhost, locuser, cmdbuf);
345 if (errorstr == NULL)
346 errorstr = "Login incorrect.\n";
350 lc = login_getpwclass(pwd);
352 if (chdir(pwd->pw_dir) < 0) {
354 if (chdir("/") < 0 ||
355 login_getcapbool(lc, "requirehome", !!pwd->pw_uid)) {
356 syslog(LOG_INFO|LOG_AUTH,
357 "%s@%s as %s: no home directory. cmd='%.80s'",
358 remuser, fromhost, locuser, cmdbuf);
359 error("No remote home directory.\n");
365 syslog(LOG_INFO|LOG_AUTH,
366 "%s@%s as %s: no home directory. cmd='%.80s'",
367 remuser, fromhost, locuser, cmdbuf);
368 error("No remote directory.\n");
376 (pwd->pw_expire && time(NULL) >= pwd->pw_expire) ||
377 iruserok_sa(fromp, fromp->su_len, pwd->pw_uid == 0,
378 remuser, locuser) < 0) {
380 syslog(LOG_INFO|LOG_AUTH,
381 "%s@%s as %s: permission denied (%s). cmd='%.80s'",
382 remuser, fromhost, locuser, __rcmd_errstr,
385 syslog(LOG_INFO|LOG_AUTH,
386 "%s@%s as %s: permission denied. cmd='%.80s'",
387 remuser, fromhost, locuser, cmdbuf);
390 if (errorstr == NULL)
391 errorstr = "Login incorrect.\n";
392 error(errorstr, fromhost);
396 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) {
397 error("Logins currently disabled.\n");
401 if (lc != NULL && fromp->su_family == AF_INET) { /*XXX*/
402 char remote_ip[MAXHOSTNAMELEN];
404 strncpy(remote_ip, numericname,
405 sizeof(remote_ip) - 1);
406 remote_ip[sizeof(remote_ip) - 1] = 0;
407 if (!auth_hostok(lc, fromhost, remote_ip)) {
408 syslog(LOG_INFO|LOG_AUTH,
409 "%s@%s as %s: permission denied (%s). cmd='%.80s'",
410 remuser, fromhost, locuser, __rcmd_errstr,
412 error("Login incorrect.\n");
415 if (!auth_timeok(lc, time(NULL))) {
416 error("Logins not available right now\n");
420 #endif /* !LOGIN_CAP */
422 /* before fork, while we're session leader */
423 if (setlogin(pwd->pw_name) < 0)
424 syslog(LOG_ERR, "setlogin() failed: %m");
427 write(STDERR_FILENO, "\0", 1);
432 error("Can't make pipe.\n");
438 error("Can't make 2nd pipe.\n");
442 error("Can't make 3rd pipe.\n");
449 error("Can't fork; try again.\n");
455 static char msg[] = SECURE_MESSAGE;
458 des_enc_write(s, msg, sizeof(msg) - 1,
459 schedule, &kdata->session);
471 FD_SET(s, &readfrom);
472 FD_SET(pv[0], &readfrom);
480 FD_SET(pv2[0], &writeto);
481 FD_SET(pv1[0], &readfrom);
483 nfd = MAX(nfd, pv2[0]);
484 nfd = MAX(nfd, pv1[0]);
487 ioctl(pv[0], FIONBIO, (char *)&one);
489 /* should set s nbio! */
496 if (select(nfd, &ready,
502 if (select(nfd, &ready, NULL,
505 if (FD_ISSET(s, &ready)) {
509 ret = des_enc_read(s, &sig, 1,
510 schedule, &kdata->session);
513 ret = read(s, &sig, 1);
515 FD_CLR(s, &readfrom);
519 if (FD_ISSET(pv[0], &ready)) {
521 cc = read(pv[0], buf, sizeof(buf));
523 shutdown(s, SHUT_RDWR);
524 FD_CLR(pv[0], &readfrom);
528 des_enc_write(s, buf,
537 if (doencrypt && FD_ISSET(pv1[0], &ready)) {
539 cc = read(pv1[0], buf, sizeof(buf));
541 shutdown(pv1[0], SHUT_RDWR);
542 FD_CLR(pv1[0], &readfrom);
544 des_enc_write(STDOUT_FILENO,
550 if (doencrypt && FD_ISSET(pv2[0], &wready)) {
552 cc = des_enc_read(STDIN_FILENO,
554 schedule, &kdata->session);
556 shutdown(pv2[0], SHUT_RDWR);
557 FD_CLR(pv2[0], &writeto);
559 write(pv2[0], buf, cc);
564 } while (FD_ISSET(s, &readfrom) ||
566 (doencrypt && FD_ISSET(pv1[0], &readfrom)) ||
568 FD_ISSET(pv[0], &readfrom));
571 setpgrp(0, getpid());
576 close(pv1[0]); close(pv2[0]);
586 if (*pwd->pw_shell == '\0')
587 pwd->pw_shell = bshell;
589 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6);
590 strcat(path, _PATH_DEFPATH);
591 strncat(shell, pwd->pw_shell, sizeof(shell)-7);
592 strncat(username, pwd->pw_name, sizeof(username)-6);
593 cp = strrchr(pwd->pw_shell, '/');
599 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETALL) != 0) {
600 syslog(LOG_ERR, "setusercontext: %m");
605 setgid((gid_t)pwd->pw_gid);
606 initgroups(pwd->pw_name, pwd->pw_gid);
607 setuid((uid_t)pwd->pw_uid);
610 if (log_success || pwd->pw_uid == 0) {
611 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'",
612 remuser, fromhost, locuser, cmdbuf);
614 execl(pwd->pw_shell, cp, "-c", cmdbuf, NULL);
615 perror(pwd->pw_shell);
620 * Report error to client. Note: can't be used until second socket has
621 * connected to client, or older clients will hang waiting for that
626 error(const char *fmt, ...)
630 char *bp, buf[BUFSIZ];
633 if (sent_null == 0) {
638 vsnprintf(bp, sizeof(buf) - 1, fmt, ap);
639 write(STDERR_FILENO, buf, len + strlen(bp));
643 getstr(char *buf, int cnt, const char *err)
648 if (read(STDIN_FILENO, &c, 1) != 1)
652 error("%s too long\n", err);
659 * Check whether host h is in our local domain,
660 * defined as sharing the last two components of the domain part,
661 * or the entire domain part if the local domain has only one component.
662 * If either name is unqualified (contains no '.'),
663 * assume that the host is local, as it will be
664 * interpreted as such.
667 local_domain(char *h)
669 char localhost[MAXHOSTNAMELEN];
673 gethostname(localhost, sizeof(localhost) - 1);
674 localhost[sizeof(localhost) - 1] = '\0';
675 p1 = topdomain(localhost);
677 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2))
685 char *p, *maybe = NULL;
688 for (p = h + strlen(h); p >= h; p--) {
702 syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS);