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. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef lint
31static const char copyright[] =
32"@(#) Copyright (c) 1983, 1993\n\
33	The Regents of the University of California.  All rights reserved.\n";
34#endif /* not lint */
35
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)fingerd.c	8.1 (Berkeley) 6/4/93";
39#endif
40static const char rcsid[] =
41  "$FreeBSD$";
42#endif /* not lint */
43
44#include <sys/types.h>
45#include <sys/param.h>
46#include <sys/socket.h>
47#include <netinet/in.h>
48#include <netinet/tcp.h>
49#include <arpa/inet.h>
50#include <errno.h>
51
52#include <unistd.h>
53#include <syslog.h>
54#include <libutil.h>
55#include <netdb.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include "pathnames.h"
60#ifdef USE_BLACKLIST
61#include <blacklist.h>
62#endif
63
64void logerr(const char *, ...) __printflike(1, 2) __dead2;
65
66int
67main(int argc, char *argv[])
68{
69	FILE *fp;
70	int ch;
71	char *lp;
72	struct sockaddr_storage ss;
73	socklen_t sval;
74	int p[2], debug, kflag, logging, pflag, secure;
75#define	ENTRIES	50
76	char **ap, *av[ENTRIES + 1], **comp, line[1024], *prog;
77	char rhost[MAXHOSTNAMELEN];
78
79	prog = _PATH_FINGER;
80	debug = logging = kflag = pflag = secure = 0;
81	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
82	opterr = 0;
83	while ((ch = getopt(argc, argv, "dklp:s")) != -1)
84		switch (ch) {
85		case 'd':
86			debug = 1;
87			break;
88		case 'k':
89			kflag = 1;
90			break;
91		case 'l':
92			logging = 1;
93			break;
94		case 'p':
95			prog = optarg;
96			pflag = 1;
97			break;
98		case 's':
99			secure = 1;
100			break;
101		case '?':
102		default:
103			logerr("illegal option -- %c", optopt);
104		}
105
106	/*
107	 * Enable server-side Transaction TCP.
108	 */
109	if (!debug) {
110		int one = 1;
111		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
112			       sizeof one) < 0) {
113			logerr("setsockopt(TCP_NOPUSH) failed: %m");
114		}
115	}
116
117	if (!fgets(line, sizeof(line), stdin))
118		exit(1);
119
120	if (!debug && (logging || pflag)) {
121		sval = sizeof(ss);
122		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
123			logerr("getpeername: %s", strerror(errno));
124		realhostname_sa(rhost, sizeof rhost - 1,
125				(struct sockaddr *)&ss, sval);
126		rhost[sizeof(rhost) - 1] = '\0';
127		if (pflag)
128			setenv("FINGERD_REMOTE_HOST", rhost, 1);
129	}
130
131	if (logging) {
132		char *t;
133		char *end;
134
135		end = memchr(line, 0, sizeof(line));
136		if (end == NULL) {
137			if ((t = malloc(sizeof(line) + 1)) == NULL)
138				logerr("malloc: %s", strerror(errno));
139			memcpy(t, line, sizeof(line));
140			t[sizeof(line)] = 0;
141		} else {
142			if ((t = strdup(line)) == NULL)
143				logerr("strdup: %s", strerror(errno));
144		}
145		for (end = t; *end; end++)
146			if (*end == '\n' || *end == '\r')
147				*end = ' ';
148		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
149	}
150
151	comp = &av[2];
152	av[3] = "--";
153	if (kflag)
154		*comp-- = "-k";
155	for (lp = line, ap = &av[4];;) {
156		*ap = strtok(lp, " \t\r\n");
157		if (!*ap) {
158			if (secure && ap == &av[4]) {
159#ifdef USE_BLACKLIST
160				blacklist(1, STDIN_FILENO, "nousername");
161#endif
162				puts("must provide username\r\n");
163				exit(1);
164			}
165			break;
166		}
167		if (secure && strchr(*ap, '@')) {
168#ifdef USE_BLACKLIST
169			blacklist(1, STDIN_FILENO, "noforwarding");
170#endif
171			puts("forwarding service denied\r\n");
172			exit(1);
173		}
174
175		/* RFC742: "/[Ww]" == "-l" */
176		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
177			*comp-- = "-l";
178		}
179		else if (++ap == av + ENTRIES) {
180			*ap = NULL;
181			break;
182		}
183		lp = NULL;
184	}
185
186	if ((lp = strrchr(prog, '/')) != NULL)
187		*comp = ++lp;
188	else
189		*comp = prog;
190	if (pipe(p) < 0)
191		logerr("pipe: %s", strerror(errno));
192
193	if (debug) {
194		fprintf(stderr, "%s", prog);
195		for (ap = comp; *ap != NULL; ++ap)
196			fprintf(stderr, " %s", *ap);
197		fprintf(stderr, "\n");
198	}
199
200	switch(vfork()) {
201	case 0:
202		(void)close(p[0]);
203		if (p[1] != STDOUT_FILENO) {
204			(void)dup2(p[1], STDOUT_FILENO);
205			(void)close(p[1]);
206		}
207		dup2(STDOUT_FILENO, STDERR_FILENO);
208
209#ifdef USE_BLACKLIST
210		blacklist(0, STDIN_FILENO, "success");
211#endif
212		execv(prog, comp);
213		write(STDERR_FILENO, prog, strlen(prog));
214#define MSG ": cannot execute\n"
215		write(STDERR_FILENO, MSG, strlen(MSG));
216#undef MSG
217		_exit(1);
218	case -1:
219		logerr("fork: %s", strerror(errno));
220	}
221	(void)close(p[1]);
222	if (!(fp = fdopen(p[0], "r")))
223		logerr("fdopen: %s", strerror(errno));
224	while ((ch = getc(fp)) != EOF) {
225		if (ch == '\n')
226			putchar('\r');
227		putchar(ch);
228	}
229	exit(0);
230}
231
232#include <stdarg.h>
233
234void
235logerr(const char *fmt, ...)
236{
237	va_list ap;
238	va_start(ap, fmt);
239	(void)vsyslog(LOG_ERR, fmt, ap);
240	va_end(ap);
241	exit(1);
242	/* NOTREACHED */
243}
244