xref: /original-bsd/usr.bin/rlogin/kcmd.c (revision c3e32dec)
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	8.1 (Berkeley) 06/06/93";
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 	/* If realm is null, look up from table */
88 	if (realm == NULL || realm[0] == '\0')
89 		realm = krb_realmofhost(host_save);
90 
91 	oldmask = sigblock(sigmask(SIGURG));
92 	for (;;) {
93 		s = getport(&lport);
94 		if (s < 0) {
95 			if (errno == EAGAIN)
96 				fprintf(stderr,
97 					"kcmd(socket): All ports in use\n");
98 			else
99 				perror("kcmd: socket");
100 			sigsetmask(oldmask);
101 			return (-1);
102 		}
103 		fcntl(s, F_SETOWN, pid);
104 		sin.sin_family = hp->h_addrtype;
105 #if defined(ultrix) || defined(sun)
106 		bcopy(hp->h_addr, (caddr_t)&sin.sin_addr, hp->h_length);
107 #else
108 		bcopy(hp->h_addr_list[0], (caddr_t)&sin.sin_addr, hp->h_length);
109 #endif
110 		sin.sin_port = rport;
111 		if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
112 			break;
113 		(void) close(s);
114 		if (errno == EADDRINUSE) {
115 			lport--;
116 			continue;
117 		}
118 		/*
119 		 * don't wait very long for Kerberos rcmd.
120 		 */
121 		if (errno == ECONNREFUSED && timo <= 4) {
122 			/* sleep(timo); don't wait at all here */
123 			timo *= 2;
124 			continue;
125 		}
126 #if !(defined(ultrix) || defined(sun))
127 		if (hp->h_addr_list[1] != NULL) {
128 			int oerrno = errno;
129 
130 			fprintf(stderr,
131 			    "kcmd: connect to address %s: ",
132 			    inet_ntoa(sin.sin_addr));
133 			errno = oerrno;
134 			perror(NULL);
135 			hp->h_addr_list++;
136 			bcopy(hp->h_addr_list[0], (caddr_t)&sin.sin_addr,
137 			    hp->h_length);
138 			fprintf(stderr, "Trying %s...\n",
139 				inet_ntoa(sin.sin_addr));
140 			continue;
141 		}
142 #endif /* !(defined(ultrix) || defined(sun)) */
143 		if (errno != ECONNREFUSED)
144 			perror(hp->h_name);
145 		sigsetmask(oldmask);
146 		return (-1);
147 	}
148 	lport--;
149 	if (fd2p == 0) {
150 		write(s, "", 1);
151 		lport = 0;
152 	} else {
153 		char num[8];
154 		int s2 = getport(&lport), s3;
155 		int len = sizeof(from);
156 
157 		if (s2 < 0) {
158 			status = -1;
159 			goto bad;
160 		}
161 		listen(s2, 1);
162 		(void) sprintf(num, "%d", lport);
163 		if (write(s, num, strlen(num) + 1) != strlen(num) + 1) {
164 			perror("kcmd(write): setting up stderr");
165 			(void) close(s2);
166 			status = -1;
167 			goto bad;
168 		}
169 		s3 = accept(s2, (struct sockaddr *)&from, &len);
170 		(void) close(s2);
171 		if (s3 < 0) {
172 			perror("kcmd:accept");
173 			lport = 0;
174 			status = -1;
175 			goto bad;
176 		}
177 		*fd2p = s3;
178 		from.sin_port = ntohs((u_short)from.sin_port);
179 		if (from.sin_family != AF_INET ||
180 		    from.sin_port >= IPPORT_RESERVED) {
181 			fprintf(stderr,
182 			 "kcmd(socket): protocol failure in circuit setup.\n");
183 			status = -1;
184 			goto bad2;
185 		}
186 	}
187 	/*
188 	 * Kerberos-authenticated service.  Don't have to send locuser,
189 	 * since its already in the ticket, and we'll extract it on
190 	 * the other side.
191 	 */
192 	/* (void) write(s, locuser, strlen(locuser)+1); */
193 
194 	/* set up the needed stuff for mutual auth, but only if necessary */
195 	if (authopts & KOPT_DO_MUTUAL) {
196 		int sin_len;
197 		*faddr = sin;
198 
199 		sin_len = sizeof(struct sockaddr_in);
200 		if (getsockname(s, (struct sockaddr *)laddr, &sin_len) < 0) {
201 			perror("kcmd(getsockname)");
202 			status = -1;
203 			goto bad2;
204 		}
205 	}
206 	if ((status = krb_sendauth(authopts, s, ticket, service, *ahost,
207 			       realm, (unsigned long) getpid(), msg_data,
208 			       cred, schedule,
209 			       laddr,
210 			       faddr,
211 			       "KCMDV0.1")) != KSUCCESS)
212 		goto bad2;
213 
214 	(void) write(s, remuser, strlen(remuser)+1);
215 	(void) write(s, cmd, strlen(cmd)+1);
216 
217 	if ((rc = read(s, &c, 1)) != 1) {
218 		if (rc == -1)
219 			perror(*ahost);
220 		else
221 			fprintf(stderr,"kcmd: bad connection with remote host\n");
222 		status = -1;
223 		goto bad2;
224 	}
225 	if (c != '\0') {
226 		while (read(s, &c, 1) == 1) {
227 			(void) write(2, &c, 1);
228 			if (c == '\n')
229 				break;
230 		}
231 		status = -1;
232 		goto bad2;
233 	}
234 	sigsetmask(oldmask);
235 	*sock = s;
236 	return (KSUCCESS);
237 bad2:
238 	if (lport)
239 		(void) close(*fd2p);
240 bad:
241 	(void) close(s);
242 	sigsetmask(oldmask);
243 	return (status);
244 }
245 
246 int
247 getport(alport)
248 	int *alport;
249 {
250 	struct sockaddr_in sin;
251 	int s;
252 
253 	sin.sin_family = AF_INET;
254 	sin.sin_addr.s_addr = INADDR_ANY;
255 	s = socket(AF_INET, SOCK_STREAM, 0);
256 	if (s < 0)
257 		return (-1);
258 	for (;;) {
259 		sin.sin_port = htons((u_short)*alport);
260 		if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
261 			return (s);
262 		if (errno != EADDRINUSE) {
263 			(void) close(s);
264 			return (-1);
265 		}
266 		(*alport)--;
267 #ifdef ATHENA_COMPAT
268 		if (*alport == IPPORT_RESERVED/2) {
269 #else
270 		if (*alport == IPPORT_RESERVED) {
271 #endif
272 			(void) close(s);
273 			errno = EAGAIN;		/* close */
274 			return (-1);
275 		}
276 	}
277 }
278