xref: /freebsd/libexec/fingerd/fingerd.c (revision 6fd05b64b5b65dd4ba9b86482a0634a5f0b96c29)
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 *, ...) __printflike(1, 2);
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, pflag, 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 = pflag = secure = 0;
81 	openlog("fingerd", LOG_PID | LOG_CONS, LOG_DAEMON);
82 	opterr = 0;
83 	while ((ch = getopt(argc, argv, "lp:s")) != -1)
84 		switch (ch) {
85 		case 'l':
86 			logging = 1;
87 			break;
88 		case 'p':
89 			prog = optarg;
90 			pflag = 1;
91 			break;
92 		case 's':
93 			secure = 1;
94 			break;
95 		case '?':
96 		default:
97 			logerr("illegal option -- %c", optopt);
98 		}
99 
100 	/*
101 	 * Enable server-side Transaction TCP.
102 	 */
103 	{
104 		int one = 1;
105 		if (setsockopt(STDOUT_FILENO, IPPROTO_TCP, TCP_NOPUSH, &one,
106 			       sizeof one) < 0) {
107 			logerr("setsockopt(TCP_NOPUSH) failed: %m");
108 		}
109 	}
110 
111 	if (!fgets(line, sizeof(line), stdin))
112 		exit(1);
113 
114 	if (logging || pflag) {
115 		sval = sizeof(ss);
116 		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0)
117 			logerr("getpeername: %s", strerror(errno));
118 		realhostname_sa(rhost, sizeof rhost - 1,
119 				(struct sockaddr *)&ss, sval);
120 		rhost[sizeof(rhost) - 1] = '\0';
121 		if (pflag)
122 			setenv("FINGERD_REMOTE_HOST", rhost, 1);
123 	}
124 
125 	if (logging) {
126 		char *t;
127 		char *end;
128 
129 		end = memchr(line, 0, sizeof(line));
130 		if (end == NULL) {
131 			if ((t = malloc(sizeof(line) + 1)) == NULL)
132 				logerr("malloc: %s", strerror(errno));
133 			memcpy(t, line, sizeof(line));
134 			t[sizeof(line)] = 0;
135 		} else {
136 			if ((t = strdup(line)) == NULL)
137 				logerr("strdup: %s", strerror(errno));
138 		}
139 		for (end = t; *end; end++)
140 			if (*end == '\n' || *end == '\r')
141 				*end = ' ';
142 		syslog(LOG_NOTICE, "query from %s: `%s'", rhost, t);
143 	}
144 
145 	comp = &av[1];
146 	av[2] = "--";
147 	for (lp = line, ap = &av[3];;) {
148 		*ap = strtok(lp, " \t\r\n");
149 		if (!*ap) {
150 			if (secure && ap == &av[3]) {
151 				puts("must provide username\r\n");
152 				exit(1);
153 			}
154 			break;
155 		}
156 		if (secure && strchr(*ap, '@')) {
157 			puts("forwarding service denied\r\n");
158 			exit(1);
159 		}
160 
161 		/* RFC742: "/[Ww]" == "-l" */
162 		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
163 			av[1] = "-l";
164 			comp = &av[0];
165 		}
166 		else if (++ap == av + ENTRIES) {
167 			*ap = NULL;
168 			break;
169 		}
170 		lp = NULL;
171 	}
172 
173 	if ((lp = strrchr(prog, '/')) != NULL)
174 		*comp = ++lp;
175 	else
176 		*comp = prog;
177 	if (pipe(p) < 0)
178 		logerr("pipe: %s", strerror(errno));
179 
180 	switch(vfork()) {
181 	case 0:
182 		(void)close(p[0]);
183 		if (p[1] != STDOUT_FILENO) {
184 			(void)dup2(p[1], STDOUT_FILENO);
185 			(void)close(p[1]);
186 		}
187 		dup2(STDOUT_FILENO, STDERR_FILENO);
188 
189 		execv(prog, comp);
190 		write(STDERR_FILENO, prog, strlen(prog));
191 #define MSG ": cannot execute\n"
192 		write(STDERR_FILENO, MSG, strlen(MSG));
193 #undef MSG
194 		_exit(1);
195 	case -1:
196 		logerr("fork: %s", strerror(errno));
197 	}
198 	(void)close(p[1]);
199 	if (!(fp = fdopen(p[0], "r")))
200 		logerr("fdopen: %s", strerror(errno));
201 	while ((ch = getc(fp)) != EOF) {
202 		if (ch == '\n')
203 			putchar('\r');
204 		putchar(ch);
205 	}
206 	exit(0);
207 }
208 
209 #include <stdarg.h>
210 
211 void
212 logerr(const char *fmt, ...)
213 {
214 	va_list ap;
215 	va_start(ap, fmt);
216 	(void)vsyslog(LOG_ERR, fmt, ap);
217 	va_end(ap);
218 	exit(1);
219 	/* NOTREACHED */
220 }
221