fingerd.c revision 141918 
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 141918 2005-02-14 17:42:58Z stefanf $";
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 *, ...) __printflike(1, 2);
66
67int
68main(int argc, char *argv[])
69{
70	FILE *fp;
71	int ch;
72	char *lp;
73	struct sockaddr_storage ss;
74	socklen_t sval;
75	int p[2], logging, pflag, secure;
76#define	ENTRIES	50
77	char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
78	char rhost[MAXHOSTNAMELEN];
79
80	prog = _PATH_FINGER;
81	logging = pflag = secure = 0;
82	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
83	opterr = 0;
84	while ((ch = getopt(argc, argv, "lp:s")) != -1)
85		switch (ch) {
86		case 'l':
87			logging = 1;
88			break;
89		case 'p':
90			prog = optarg;
91			pflag = 1;
92			break;
93		case 's':
94			secure = 1;
95			break;
96		case '?':
97		default:
98			logerr("illegal option -- %c", optopt);
99		}
100
101	/*
102	 * Enable server-side Transaction TCP.
103	 */
104	{
105		int one = 1;
106		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
107			       sizeof one) < 0) {
108			logerr("setsockopt(TCP_NOPUSH) failed: %m");
109		}
110	}
111
112	if (!fgets(line, sizeof(line), stdin))
113		exit(1);
114
115	if (logging || pflag) {
116		sval = sizeof(ss);
117		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
118			logerr("getpeername: %s", strerror(errno));
119		realhostname_sa(rhost, sizeof rhost - 1,
120				(struct sockaddr *)&ss, sval);
121		rhost[sizeof(rhost) - 1] = '\0';
122		if (pflag)
123			setenv("FINGERD_REMOTE_HOST", rhost, 1);
124	}
125
126	if (logging) {
127		char *t;
128		char *end;
129
130		end = memchr(line, 0, sizeof(line));
131		if (end == NULL) {
132			if ((t = malloc(sizeof(line) + 1)) == NULL)
133				logerr("malloc: %s", strerror(errno));
134			memcpy(t, line, sizeof(line));
135			t[sizeof(line)] = 0;
136		} else {
137			if ((t = strdup(line)) == NULL)
138				logerr("strdup: %s", strerror(errno));
139		}
140		for (end = t; *end; end++)
141			if (*end == '\n' || *end == '\r')
142				*end = ' ';
143		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
144	}
145
146	comp = &av[1];
147	av[2] = "--";
148	for (lp = line, ap = &av[3];;) {
149		*ap = strtok(lp, " \t\r\n");
150		if (!*ap) {
151			if (secure && ap == &av[3]) {
152				puts("must provide username\r\n");
153				exit(1);
154			}
155			break;
156		}
157		if (secure && strchr(*ap, '@')) {
158			puts("forwarding service denied\r\n");
159			exit(1);
160		}
161
162		/* RFC742: "/[Ww]" == "-l" */
163		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
164			av[1] = "-l";
165			comp = &av[0];
166		}
167		else if (++ap == av + ENTRIES) {
168			*ap = NULL;
169			break;
170		}
171		lp = NULL;
172	}
173
174	if ((lp = strrchr(prog, '/')) != NULL)
175		*comp = ++lp;
176	else
177		*comp = prog;
178	if (pipe(p) < 0)
179		logerr("pipe: %s", strerror(errno));
180
181	switch(vfork()) {
182	case 0:
183		(void)close(p[0]);
184		if (p[1] != STDOUT_FILENO) {
185			(void)dup2(p[1], STDOUT_FILENO);
186			(void)close(p[1]);
187		}
188		dup2(STDOUT_FILENO, STDERR_FILENO);
189
190		execv(prog, comp);
191		write(STDERR_FILENO, prog, strlen(prog));
192#define MSG ": cannot execute\n"
193		write(STDERR_FILENO, MSG, strlen(MSG));
194#undef MSG
195		_exit(1);
196	case -1:
197		logerr("fork: %s", strerror(errno));
198	}
199	(void)close(p[1]);
200	if (!(fp = fdopen(p[0], "r")))
201		logerr("fdopen: %s", strerror(errno));
202	while ((ch = getc(fp)) != EOF) {
203		if (ch == '\n')
204			putchar('\r');
205		putchar(ch);
206	}
207	exit(0);
208}
209
210#include <stdarg.h>
211
212void
213logerr(const char *fmt, ...)
214{
215	va_list ap;
216	va_start(ap, fmt);
217	(void)vsyslog(LOG_ERR, fmt, ap);
218	va_end(ap);
219	exit(1);
220	/* NOTREACHED */
221}
222