fingerd.c revision 97635 
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1983, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)fingerd.c	8.1 (Berkeley) 6/4/93";
43#endif
44static const char rcsid[] =
45  "$FreeBSD: head/libexec/fingerd/fingerd.c 97635 2002-05-30 21:35:39Z wollman $";
46#endif /* not lint */
47
48#include <sys/types.h>
49#include <sys/param.h>
50#include <sys/socket.h>
51#include <netinet/in.h>
52#include <netinet/tcp.h>
53#include <arpa/inet.h>
54#include <errno.h>
55
56#include <unistd.h>
57#include <syslog.h>
58#include <libutil.h>
59#include <netdb.h>
60#include <stdio.h>
61#include <stdlib.h>
62#include <string.h>
63#include "pathnames.h"
64
65void logerr(const char *, ...);
66
67int
68main(int argc, char *argv[])
69{
70	FILE *fp;
71	int ch;
72	char *lp;
73	struct sockaddr_storage ss;
74	int p[2], logging, secure, sval;
75#define	ENTRIES	50
76	char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
77	char rhost[MAXHOSTNAMELEN];
78
79	prog = _PATH_FINGER;
80	logging = secure = 0;
81	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
82	opterr = 0;
83	while ((ch = getopt(argc, argv, "slp:")) != -1)
84		switch (ch) {
85		case 'l':
86			logging = 1;
87			break;
88		case 'p':
89			prog = optarg;
90			break;
91		case 's':
92			secure = 1;
93			break;
94		case '?':
95		default:
96			logerr("illegal option -- %c", optopt);
97		}
98
99	/*
100	 * Enable server-side Transaction TCP.
101	 */
102	{
103		int one = 1;
104		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
105			       sizeof one) < 0) {
106			logerr("setsockopt(TCP_NOPUSH) failed: %m");
107		}
108	}
109
110	if (!fgets(line, sizeof(line), stdin))
111		exit(1);
112
113	if (logging) {
114		char *t;
115		char *end;
116
117		end = memchr(line, 0, sizeof(line));
118		if (end == NULL) {
119			if ((t = malloc(sizeof(line) + 1)) == NULL)
120				logerr("malloc: %s", strerror(errno));
121			memcpy(t, line, sizeof(line));
122			t[sizeof(line)] = 0;
123		} else {
124			if ((t = strdup(line)) == NULL)
125				logerr("strdup: %s", strerror(errno));
126		}
127		for (end = t; *end; end++)
128			if (*end == '\n' || *end == '\r')
129				*end = ' ';
130		sval = sizeof(ss);
131		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
132			logerr("getpeername: %s", strerror(errno));
133		realhostname_sa(rhost, sizeof rhost - 1,
134				(struct sockaddr *)&ss, sval);
135		rhost[sizeof(rhost) - 1] = '\0';
136		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
137	}
138
139	comp = &av[1];
140	av[2] = "--";
141	for (lp = line, ap = &av[3];;) {
142		*ap = strtok(lp, " \t\r\n");
143		if (!*ap) {
144			if (secure && ap == &av[3]) {
145				puts("must provide username\r\n");
146				exit(1);
147			}
148			break;
149		}
150		if (secure && strchr(*ap, '@')) {
151			puts("forwarding service denied\r\n");
152			exit(1);
153		}
154
155		/* RFC742: "/[Ww]" == "-l" */
156		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
157			av[1] = "-l";
158			comp = &av[0];
159		}
160		else if (++ap == av + ENTRIES) {
161			*ap = NULL;
162			break;
163		}
164		lp = NULL;
165	}
166
167	if (lp = strrchr(prog, '/'))
168		*comp = ++lp;
169	else
170		*comp = prog;
171	if (pipe(p) < 0)
172		logerr("pipe: %s", strerror(errno));
173
174	switch(vfork()) {
175	case 0:
176		(void)close(p[0]);
177		if (p[1] != 1) {
178			(void)dup2(p[1], 1);
179			(void)close(p[1]);
180		}
181		execv(prog, comp);
182		logerr("execv: %s: %s", prog, strerror(errno));
183		_exit(1);
184	case -1:
185		logerr("fork: %s", strerror(errno));
186	}
187	(void)close(p[1]);
188	if (!(fp = fdopen(p[0], "r")))
189		logerr("fdopen: %s", strerror(errno));
190	while ((ch = getc(fp)) != EOF) {
191		if (ch == '\n')
192			putchar('\r');
193		putchar(ch);
194	}
195	exit(0);
196}
197
198#include <stdarg.h>
199
200void
201logerr(const char *fmt, ...)
202{
203	va_list ap;
204	va_start(ap, fmt);
205	(void)vsyslog(LOG_ERR, fmt, ap);
206	va_end(ap);
207	exit(1);
208	/* NOTREACHED */
209}
210