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1.2 ! deraadt 1: /* $OpenBSD: kcmd.c,v 1.1 2002/05/06 22:23:53 deraadt Exp $ */
1.1 deraadt 2: /* $NetBSD: kcmd.c,v 1.2 1995/03/21 07:58:32 cgd Exp $ */
3:
4: /*
5: * Copyright (c) 1983, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by the University of
19: * California, Berkeley and its contributors.
20: * 4. Neither the name of the University nor the names of its contributors
21: * may be used to endorse or promote products derived from this software
22: * without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34: * SUCH DAMAGE.
35: */
36:
37: #ifndef lint
38: #if 0
39: static char Xsccsid[] = "derived from @(#)rcmd.c 5.17 (Berkeley) 6/27/88";
40: static char sccsid[] = "@(#)kcmd.c 8.2 (Berkeley) 8/19/93";
41: #else
1.2 ! deraadt 42: static char rcsid[] = "$OpenBSD: kcmd.c,v 1.1 2002/05/06 22:23:53 deraadt Exp $";
1.1 deraadt 43: #endif
44: #endif /* not lint */
45:
46: #include <sys/param.h>
47: #include <sys/file.h>
48: #include <sys/socket.h>
49: #include <sys/stat.h>
50:
51: #include <netinet/in.h>
52: #include <arpa/inet.h>
53:
54: #include <des.h>
55: #include <kerberosIV/krb.h>
56:
57: #include <ctype.h>
58: #include <errno.h>
59: #include <netdb.h>
60: #include <pwd.h>
61: #include <signal.h>
62: #include <stdio.h>
63: #include <stdlib.h>
64: #include <string.h>
65: #include <unistd.h>
66:
67: #include <err.h>
68:
69: #ifndef MAXHOSTNAMELEN
70: #define MAXHOSTNAMELEN 64
71: #endif
72:
73: #define START_PORT 5120 /* arbitrary */
74:
75: int getport(int *);
76: int kcmd(int *, char **, u_short, char *, char *, char *,
77: int *, KTEXT, char *, char *, CREDENTIALS *,
78: Key_schedule, MSG_DAT *, struct sockaddr_in *,
79: struct sockaddr_in *, long);
80:
81: int
82: kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
83: cred, schedule, msg_data, laddr, faddr, authopts)
84: int *sock;
85: char **ahost;
86: u_short rport;
87: char *locuser, *remuser, *cmd;
88: int *fd2p;
89: KTEXT ticket;
90: char *service;
91: char *realm;
92: CREDENTIALS *cred;
93: Key_schedule schedule;
94: MSG_DAT *msg_data;
95: struct sockaddr_in *laddr, *faddr;
96: long authopts;
97: {
98: int s, timo = 1, pid;
99: sigset_t mask, oldmask;
100: struct sockaddr_in sin, from;
101: char c;
102: int lport = IPPORT_RESERVED - 1;
103: struct hostent *hp;
104: int rc;
105: char *host_save;
106: int status;
107:
108: pid = getpid();
109: hp = gethostbyname(*ahost);
110: if (hp == NULL) {
111: herror(*ahost);
112: return (-1);
113: }
114: if ((host_save = strdup(hp->h_name)) == NULL) {
115: warn("can't allocate memory");
116: return (-1);
117: }
118: *ahost = host_save;
119:
120: /* If realm is null, look up from table */
121: if (realm == NULL || realm[0] == '\0')
122: realm = krb_realmofhost(host_save);
123:
124: sigemptyset(&mask);
125: sigaddset(&mask, SIGURG);
126: sigprocmask(SIG_BLOCK, &mask, &oldmask);
127: for (;;) {
128: s = getport(&lport);
129: if (s < 0) {
130: if (errno == EAGAIN)
131: fprintf(stderr,
132: "kcmd(socket): All ports in use\n");
133: else
134: perror("kcmd: socket");
135: sigprocmask(SIG_SETMASK, &oldmask, NULL);
136: return (-1);
137: }
138: fcntl(s, F_SETOWN, pid);
139: bzero(&sin, sizeof sin);
140: sin.sin_len = sizeof(struct sockaddr_in);
141: sin.sin_family = hp->h_addrtype;
142: sin.sin_port = rport;
143: bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
144: if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
145: break;
146: (void) close(s);
147: if (errno == EADDRINUSE) {
148: lport--;
149: continue;
150: }
151: /*
152: * don't wait very long for Kerberos rcmd.
153: */
154: if (errno == ECONNREFUSED && timo <= 4) {
155: /* sleep(timo); don't wait at all here */
156: timo *= 2;
157: continue;
158: }
159: if (hp->h_addr_list[1] != NULL) {
160: int oerrno = errno;
161:
162: fprintf(stderr,
163: "kcmd: connect to address %s: ",
164: inet_ntoa(sin.sin_addr));
165: errno = oerrno;
166: perror(NULL);
167: hp->h_addr_list++;
168: bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
169: fprintf(stderr, "Trying %s...\n",
170: inet_ntoa(sin.sin_addr));
171: continue;
172: }
173: if (errno != ECONNREFUSED)
174: perror(hp->h_name);
175: sigprocmask(SIG_SETMASK, &oldmask, NULL);
176: return (-1);
177: }
178: if (fd2p == 0) {
179: write(s, "", 1);
180: lport = 0;
181: } else {
182: char num[8];
183: int s2 = getport(&lport), s3;
184: int len = sizeof(from);
185:
186: if (s2 < 0) {
187: status = -1;
188: goto bad;
189: }
190: listen(s2, 1);
191: (void) snprintf(num, sizeof(num), "%d", lport);
192: if (write(s, num, strlen(num) + 1) != strlen(num) + 1) {
193: perror("kcmd(write): setting up stderr");
194: (void) close(s2);
195: status = -1;
196: goto bad;
197: }
198: again:
199: s3 = accept(s2, (struct sockaddr *)&from, &len);
200: /*
201: * XXX careful for ftp bounce attacks. If discovered, shut them
202: * down and check for the real auxiliary channel to connect.
203: */
204: if (from.sin_family == AF_INET && from.sin_port == htons(20)) {
205: (void) close(s3);
206: goto again;
207: }
208: (void) close(s2);
209: if (s3 < 0) {
210: perror("kcmd:accept");
211: lport = 0;
212: status = -1;
213: goto bad;
214: }
215: *fd2p = s3;
216: from.sin_port = ntohs(from.sin_port);
217: if (from.sin_family != AF_INET ||
218: from.sin_port >= IPPORT_RESERVED ||
219: from.sin_port < IPPORT_RESERVED / 2) {
220: fprintf(stderr,
221: "kcmd(socket): protocol failure in circuit setup.\n");
222: status = -1;
223: goto bad2;
224: }
225: }
226: /*
227: * Kerberos-authenticated service. Don't have to send locuser,
228: * since its already in the ticket, and we'll extract it on
229: * the other side.
230: */
231: /* (void) write(s, locuser, strlen(locuser)+1); */
232:
233: /* set up the needed stuff for mutual auth, but only if necessary */
234: if (authopts & KOPT_DO_MUTUAL) {
235: int sin_len;
236: *faddr = sin;
237:
238: sin_len = sizeof(struct sockaddr_in);
239: if (getsockname(s, (struct sockaddr *)laddr, &sin_len) < 0) {
240: perror("kcmd(getsockname)");
241: status = -1;
242: goto bad2;
243: }
244: }
245: if ((status = krb_sendauth(authopts, s, ticket, service, *ahost,
246: realm, (unsigned long) getpid(), msg_data,
247: cred, schedule,
248: laddr,
249: faddr,
250: "KCMDV0.1")) != KSUCCESS)
251: goto bad2;
252:
253: (void) write(s, remuser, strlen(remuser)+1);
254: (void) write(s, cmd, strlen(cmd)+1);
255:
256: if ((rc = read(s, &c, 1)) != 1) {
257: if (rc == -1)
258: perror(*ahost);
259: else
260: fprintf(stderr,"kcmd: bad connection with remote host\n");
261: status = -1;
262: goto bad2;
263: }
264: if (c != '\0') {
265: while (read(s, &c, 1) == 1) {
266: (void) write(2, &c, 1);
267: if (c == '\n')
268: break;
269: }
270: status = -1;
271: goto bad2;
272: }
273: sigprocmask(SIG_SETMASK, &oldmask, NULL);
274: *sock = s;
275: return (KSUCCESS);
276: bad2:
277: if (lport)
278: (void) close(*fd2p);
279: bad:
280: (void) close(s);
281: sigprocmask(SIG_SETMASK, &oldmask, NULL);
282: return (status);
283: }
284:
285: int
286: getport(alport)
287: int *alport;
288: {
289: struct sockaddr_in sin;
290: int s;
291:
292: /* First try to get a "reserved" [sic] port, for interoperability with
293: broken klogind (aix, e.g.) */
294:
295: s = rresvport(alport);
296: if (s >= 0)
297: return s;
298:
299: /* Failed; if EACCES, we're not root, so just get an unreserved port
300: and hope that's good enough */
301:
302: if (errno != EACCES)
303: return -1;
304:
305: if (*alport < IPPORT_RESERVED)
306: *alport = START_PORT;
1.2 ! deraadt 307: memset(&sin, 0, sizeof sin);
1.1 deraadt 308: sin.sin_family = AF_INET;
309: sin.sin_addr.s_addr = INADDR_ANY;
310: s = socket(AF_INET, SOCK_STREAM, 0);
311: if (s < 0)
312: return (-1);
313: for (;;) {
314: sin.sin_port = htons((u_short)*alport);
315: if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
316: return (s);
317: if (errno != EADDRINUSE) {
318: (void) close(s);
319: return (-1);
320: }
321: (*alport)--;
322: if (*alport == IPPORT_RESERVED) {
323: (void) close(s);
324: errno = EAGAIN; /* close */
325: return (-1);
326: }
327: }
328: }