fingerd.c revision 1.27 
1/*	$OpenBSD: fingerd.c,v 1.27 2002/06/02 01:27:15 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#ifndef lint
37static char copyright[] =
38"@(#) Copyright (c) 1983, 1993\n\
39	The Regents of the University of California.  All rights reserved.\n";
40#endif /* not lint */
41
42#ifndef lint
43#if 0
44static char sccsid[] = "from: @(#)fingerd.c	8.1 (Berkeley) 6/4/93";
45#else
46static char rcsid[] = "$OpenBSD: fingerd.c,v 1.27 2002/06/02 01:27:15 deraadt Exp $";
47#endif
48#endif /* not lint */
49
50#include <sys/types.h>
51#include <sys/socket.h>
52#include <netinet/in.h>
53#include <arpa/inet.h>
54#include <errno.h>
55
56#include <unistd.h>
57#include <syslog.h>
58#include <netdb.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <stdarg.h>
63#include "pathnames.h"
64
65void err(const char *, ...);
66void usage(void);
67
68void
69usage()
70{
71	syslog(LOG_ERR,
72	    "usage: fingerd [-slumMpS] [-P filename]");
73	exit(2);
74}
75
76
77int
78main(argc, argv)
79	int argc;
80	char *argv[];
81{
82	FILE *fp;
83	int ch, ac = 2;
84	int p[2], logging, secure, user_required, short_list;
85#define	ENTRIES	50
86	char **comp, *prog;
87	char **ap, *av[ENTRIES + 1], line[8192], *lp, *hname;
88	char hostbuf[MAXHOSTNAMELEN];
89
90	prog = _PATH_FINGER;
91	logging = secure = user_required = short_list = 0;
92	openlog("fingerd", LOG_PID, LOG_DAEMON);
93	opterr = 0;
94	while ((ch = getopt(argc, argv, "sluSmMpP:")) != -1)
95		switch (ch) {
96		case 'l':
97			logging = 1;
98			break;
99		case 'P':
100			prog = optarg;
101			break;
102		case 's':
103			secure = 1;
104			break;
105		case 'u':
106			user_required = 1;
107			break;
108		case 'S':
109			if (ac < ENTRIES) {
110				short_list = 1;
111				av[ac++] = "-s";
112			}
113			break;
114		case 'm':
115			if (ac < ENTRIES)
116				av[ac++] = "-m";
117			break;
118		case 'M':
119			if (ac < ENTRIES)
120				av[ac++] = "-M";
121			break;
122		case 'p':
123			if (ac < ENTRIES)
124				av[ac++] = "-p";
125			break;
126		default:
127			usage();
128		}
129
130	if (logging) {
131		struct sockaddr_storage ss;
132		struct sockaddr *sa;
133		int sval;
134
135		sval = sizeof(ss);
136		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0) {
137			/* err("getpeername: %s", strerror(errno)); */
138			exit(1);
139		}
140		sa = (struct sockaddr *)&ss;
141		if (getnameinfo(sa, sa->sa_len, hostbuf, sizeof(hostbuf),
142		    NULL, 0, 0) != 0) {
143			strlcpy(hostbuf, "?", sizeof(hostbuf));
144		}
145		hname = hostbuf;
146	}
147
148	if (fgets(line, sizeof(line), stdin) == NULL) {
149		if (logging)
150			syslog(LOG_NOTICE, "query from %s: %s", hname,
151			    feof(stdin) ? "EOF" : strerror(errno));
152		exit(1);
153	}
154
155	if (logging)
156		syslog(LOG_NOTICE, "query from %s: `%.*s'", hname,
157		    (int)strcspn(line, "\r\n"), line);
158
159	/*
160	 * Note: we assume that finger(1) will treat "--" as end of
161	 * command args (ie: that it uses getopt(3)).
162	 */
163	av[ac++] = "--";
164	comp = &av[1];
165	for (lp = line, ap = &av[ac]; ac < ENTRIES;) {
166		if ((*ap = strtok(lp, " \t\r\n")) == NULL)
167			break;
168		lp = NULL;
169		if (secure && strchr(*ap, '@')) {
170			(void) puts("forwarding service denied\r");
171			exit(1);
172		}
173
174		ch = strlen(*ap);
175		while ((*ap)[ch-1] == '@')
176			(*ap)[--ch] = '\0';
177		if (**ap == '\0')
178			continue;
179
180		/* RFC1196: "/[Ww]" == "-l" */
181		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
182			if (!short_list) {
183				av[1] = "-l";
184				comp = &av[0];
185			}
186		} else {
187			ap++;
188			ac++;
189		}
190	}
191	av[ENTRIES - 1] = NULL;
192
193	if ((lp = strrchr(prog, '/')))
194		*comp = ++lp;
195	else
196		*comp = prog;
197
198	if (user_required) {
199		for (ap = comp + 1; strcmp("--", *(ap++)); )
200			;
201		if (*ap == NULL) {
202			(void) puts("must provide username\r");
203			exit(1);
204		}
205	}
206
207	if (pipe(p) < 0)
208		err("pipe: %s", strerror(errno));
209
210	switch (vfork()) {
211	case 0:
212		(void) close(p[0]);
213		if (p[1] != 1) {
214			(void) dup2(p[1], 1);
215			(void) close(p[1]);
216		}
217		execv(prog, comp);
218		err("execv: %s: %s", prog, strerror(errno));
219		_exit(1);
220	case -1:
221		err("fork: %s", strerror(errno));
222	}
223	(void) close(p[1]);
224	if (!(fp = fdopen(p[0], "r")))
225		err("fdopen: %s", strerror(errno));
226	while ((ch = getc(fp)) != EOF) {
227		if (ch == '\n')
228			putchar('\r');
229		putchar(ch);
230	}
231	exit(0);
232}
233
234void
235err(const char *fmt, ...)
236{
237	va_list ap;
238
239	va_start(ap, fmt);
240	(void) vsyslog(LOG_ERR, fmt, ap);
241	va_end(ap);
242	exit(1);
243	/* NOTREACHED */
244}
245