xref: /freebsd/libexec/fingerd/fingerd.c (revision f24b4798540024a168e65c32254478be4c8815e2)
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
35 static 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
42 static char sccsid[] = "@(#)fingerd.c	8.1 (Berkeley) 6/4/93";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
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 
65 void logerr(const char *, ...);
66 
67 int
68 main(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 
200 void
201 logerr(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