xref: /original-bsd/usr.bin/rlogin/kcmd.c (revision 95ecee29)
1 /*
2  * Copyright (c) 1983, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  */
7 
8 #ifndef lint
9 static char Xsccsid[] = "derived from @(#)rcmd.c 5.17 (Berkeley) 6/27/88";
10 static char sccsid[] = "@(#)kcmd.c	8.2 (Berkeley) 08/19/93";
11 #endif /* not lint */
12 
13 #include <sys/param.h>
14 #include <sys/file.h>
15 #include <sys/socket.h>
16 #include <sys/stat.h>
17 
18 #include <netinet/in.h>
19 #include <arpa/inet.h>
20 
21 #include <kerberosIV/des.h>
22 #include <kerberosIV/krb.h>
23 #include <kerberosIV/kparse.h>
24 
25 #include <ctype.h>
26 #include <errno.h>
27 #include <netdb.h>
28 #include <pwd.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "krb.h"
36 
37 #ifndef MAXHOSTNAMELEN
38 #define MAXHOSTNAMELEN 64
39 #endif
40 
41 #define	START_PORT	5120	 /* arbitrary */
42 
43 int	getport __P((int *));
44 
45 int
46 kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
47     cred, schedule, msg_data, laddr, faddr, authopts)
48 	int *sock;
49 	char **ahost;
50 	u_short rport;
51 	char *locuser, *remuser, *cmd;
52 	int *fd2p;
53 	KTEXT ticket;
54 	char *service;
55 	char *realm;
56 	CREDENTIALS *cred;
57 	Key_schedule schedule;
58 	MSG_DAT *msg_data;
59 	struct sockaddr_in *laddr, *faddr;
60 	long authopts;
61 {
62 	int s, timo = 1, pid;
63 	long oldmask;
64 	struct sockaddr_in sin, from;
65 	char c;
66 #ifdef ATHENA_COMPAT
67 	int lport = IPPORT_RESERVED - 1;
68 #else
69 	int lport = START_PORT;
70 #endif
71 	struct hostent *hp;
72 	int rc;
73 	char *host_save;
74 	int status;
75 
76 	pid = getpid();
77 	hp = gethostbyname(*ahost);
78 	if (hp == NULL) {
79 		/* fprintf(stderr, "%s: unknown host\n", *ahost); */
80 		return (-1);
81 	}
82 
83 	host_save = malloc(strlen(hp->h_name) + 1);
84 	strcpy(host_save, hp->h_name);
85 	*ahost = host_save;
86 
87 #ifdef KERBEROS
88 	/* If realm is null, look up from table */
89 	if (realm == NULL || realm[0] == '\0')
90 		realm = krb_realmofhost(host_save);
91 #endif /* KERBEROS */
92 
93 	oldmask = sigblock(sigmask(SIGURG));
94 	for (;;) {
95 		s = getport(&lport);
96 		if (s < 0) {
97 			if (errno == EAGAIN)
98 				fprintf(stderr,
99 					"kcmd(socket): All ports in use\n");
100 			else
101 				perror("kcmd: socket");
102 			sigsetmask(oldmask);
103 			return (-1);
104 		}
105 		fcntl(s, F_SETOWN, pid);
106 		sin.sin_family = hp->h_addrtype;
107 #if defined(ultrix) || defined(sun)
108 		bcopy(hp->h_addr, (caddr_t)&sin.sin_addr, hp->h_length);
109 #else
110 		bcopy(hp->h_addr_list[0], (caddr_t)&sin.sin_addr, hp->h_length);
111 #endif
112 		sin.sin_port = rport;
113 		if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
114 			break;
115 		(void) close(s);
116 		if (errno == EADDRINUSE) {
117 			lport--;
118 			continue;
119 		}
120 		/*
121 		 * don't wait very long for Kerberos rcmd.
122 		 */
123 		if (errno == ECONNREFUSED && timo <= 4) {
124 			/* sleep(timo); don't wait at all here */
125 			timo *= 2;
126 			continue;
127 		}
128 #if !(defined(ultrix) || defined(sun))
129 		if (hp->h_addr_list[1] != NULL) {
130 			int oerrno = errno;
131 
132 			fprintf(stderr,
133 			    "kcmd: connect to address %s: ",
134 			    inet_ntoa(sin.sin_addr));
135 			errno = oerrno;
136 			perror(NULL);
137 			hp->h_addr_list++;
138 			bcopy(hp->h_addr_list[0], (caddr_t)&sin.sin_addr,
139 			    hp->h_length);
140 			fprintf(stderr, "Trying %s...\n",
141 				inet_ntoa(sin.sin_addr));
142 			continue;
143 		}
144 #endif /* !(defined(ultrix) || defined(sun)) */
145 		if (errno != ECONNREFUSED)
146 			perror(hp->h_name);
147 		sigsetmask(oldmask);
148 		return (-1);
149 	}
150 	lport--;
151 	if (fd2p == 0) {
152 		write(s, "", 1);
153 		lport = 0;
154 	} else {
155 		char num[8];
156 		int s2 = getport(&lport), s3;
157 		int len = sizeof(from);
158 
159 		if (s2 < 0) {
160 			status = -1;
161 			goto bad;
162 		}
163 		listen(s2, 1);
164 		(void) sprintf(num, "%d", lport);
165 		if (write(s, num, strlen(num) + 1) != strlen(num) + 1) {
166 			perror("kcmd(write): setting up stderr");
167 			(void) close(s2);
168 			status = -1;
169 			goto bad;
170 		}
171 		s3 = accept(s2, (struct sockaddr *)&from, &len);
172 		(void) close(s2);
173 		if (s3 < 0) {
174 			perror("kcmd:accept");
175 			lport = 0;
176 			status = -1;
177 			goto bad;
178 		}
179 		*fd2p = s3;
180 		from.sin_port = ntohs((u_short)from.sin_port);
181 		if (from.sin_family != AF_INET ||
182 		    from.sin_port >= IPPORT_RESERVED) {
183 			fprintf(stderr,
184 			 "kcmd(socket): protocol failure in circuit setup.\n");
185 			status = -1;
186 			goto bad2;
187 		}
188 	}
189 	/*
190 	 * Kerberos-authenticated service.  Don't have to send locuser,
191 	 * since its already in the ticket, and we'll extract it on
192 	 * the other side.
193 	 */
194 	/* (void) write(s, locuser, strlen(locuser)+1); */
195 
196 	/* set up the needed stuff for mutual auth, but only if necessary */
197 	if (authopts & KOPT_DO_MUTUAL) {
198 		int sin_len;
199 		*faddr = sin;
200 
201 		sin_len = sizeof(struct sockaddr_in);
202 		if (getsockname(s, (struct sockaddr *)laddr, &sin_len) < 0) {
203 			perror("kcmd(getsockname)");
204 			status = -1;
205 			goto bad2;
206 		}
207 	}
208 #ifdef KERBEROS
209 	if ((status = krb_sendauth(authopts, s, ticket, service, *ahost,
210 			       realm, (unsigned long) getpid(), msg_data,
211 			       cred, schedule,
212 			       laddr,
213 			       faddr,
214 			       "KCMDV0.1")) != KSUCCESS)
215 		goto bad2;
216 #endif /* KERBEROS */
217 
218 	(void) write(s, remuser, strlen(remuser)+1);
219 	(void) write(s, cmd, strlen(cmd)+1);
220 
221 	if ((rc = read(s, &c, 1)) != 1) {
222 		if (rc == -1)
223 			perror(*ahost);
224 		else
225 			fprintf(stderr,"kcmd: bad connection with remote host\n");
226 		status = -1;
227 		goto bad2;
228 	}
229 	if (c != '\0') {
230 		while (read(s, &c, 1) == 1) {
231 			(void) write(2, &c, 1);
232 			if (c == '\n')
233 				break;
234 		}
235 		status = -1;
236 		goto bad2;
237 	}
238 	sigsetmask(oldmask);
239 	*sock = s;
240 	return (KSUCCESS);
241 bad2:
242 	if (lport)
243 		(void) close(*fd2p);
244 bad:
245 	(void) close(s);
246 	sigsetmask(oldmask);
247 	return (status);
248 }
249 
250 int
251 getport(alport)
252 	int *alport;
253 {
254 	struct sockaddr_in sin;
255 	int s;
256 
257 	sin.sin_family = AF_INET;
258 	sin.sin_addr.s_addr = INADDR_ANY;
259 	s = socket(AF_INET, SOCK_STREAM, 0);
260 	if (s < 0)
261 		return (-1);
262 	for (;;) {
263 		sin.sin_port = htons((u_short)*alport);
264 		if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
265 			return (s);
266 		if (errno != EADDRINUSE) {
267 			(void) close(s);
268 			return (-1);
269 		}
270 		(*alport)--;
271 #ifdef ATHENA_COMPAT
272 		if (*alport == IPPORT_RESERVED/2) {
273 #else
274 		if (*alport == IPPORT_RESERVED) {
275 #endif
276 			(void) close(s);
277 			errno = EAGAIN;		/* close */
278 			return (-1);
279 		}
280 	}
281 }
282