inetcf.c revision 350345 
1/* $FreeBSD: stable/11/contrib/tcp_wrappers/inetcf.c 350345 2019-07-26 02:49:34Z brooks $ */
2 /*
3  * Routines to parse an inetd.conf or tlid.conf file. This would be a great
4  * job for a PERL script.
5  *
6  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
7  */
8
9#ifndef lint
10static char sccsid[] = "@(#) inetcf.c 1.7 97/02/12 02:13:23";
11#endif
12
13#include <sys/types.h>
14#include <sys/stat.h>
15#include <stdio.h>
16#include <errno.h>
17#include <stdlib.h>
18#include <string.h>
19
20#include "tcpd.h"
21#include "inetcf.h"
22#include "scaffold.h"
23
24 /*
25  * Network configuration files may live in unusual places. Here are some
26  * guesses. Shorter names follow longer ones.
27  */
28char   *inet_files[] = {
29    "/private/etc/inetd.conf",		/* NEXT */
30    "/etc/inet/inetd.conf",		/* SYSV4 */
31    "/usr/etc/inetd.conf",		/* IRIX?? */
32    "/etc/inetd.conf",			/* BSD */
33    "/etc/net/tlid.conf",		/* SYSV4?? */
34    "/etc/saf/tlid.conf",		/* SYSV4?? */
35    "/etc/tlid.conf",			/* SYSV4?? */
36    0,
37};
38
39static void inet_chk(char *protocol, char *path, char *arg0, char *arg1);
40static char *base_name(char *path);
41extern char *percent_m(char *obuf, char *ibuf);
42
43 /*
44  * Structure with everything we know about a service.
45  */
46struct inet_ent {
47    struct inet_ent *next;
48    int     type;
49    char    name[1];
50};
51
52static struct inet_ent *inet_list = 0;
53
54static char whitespace[] = " \t\r\n";
55
56/* inet_conf - read in and examine inetd.conf (or tlid.conf) entries */
57
58char   *inet_cfg(conf)
59char   *conf;
60{
61    char    buf[BUFSIZ];
62    FILE   *fp;
63    char   *service;
64    char   *protocol;
65    char   *user;
66    char   *path;
67    char   *arg0;
68    char   *arg1;
69    struct tcpd_context saved_context;
70    int     i;
71    struct stat st;
72
73    saved_context = tcpd_context;
74
75    /*
76     * The inetd.conf (or tlid.conf) information is so useful that we insist
77     * on its availability. When no file is given run a series of educated
78     * guesses.
79     */
80    if (conf != 0) {
81	if ((fp = fopen(conf, "r")) == 0) {
82	    fprintf(stderr, percent_m(buf, "open %s: %m\n"), conf);
83	    exit(1);
84	}
85    } else {
86	for (i = 0; inet_files[i] && (fp = fopen(inet_files[i], "r")) == 0; i++)
87	     /* void */ ;
88	if (fp == 0) {
89	    fprintf(stderr, "Cannot find your inetd.conf or tlid.conf file.\n");
90	    fprintf(stderr, "Please specify its location.\n");
91	    exit(1);
92	}
93	conf = inet_files[i];
94	check_path(conf, &st);
95    }
96
97    /*
98     * Process the file. After the 7.0 wrapper release it became clear that
99     * there are many more inetd.conf formats than the 8 systems that I had
100     * studied. EP/IX uses a two-line specification for rpc services; HP-UX
101     * permits long lines to be broken with backslash-newline.
102     */
103    tcpd_context.file = conf;
104    tcpd_context.line = 0;
105    while (xgets(buf, sizeof(buf), fp)) {
106	service = strtok(buf, whitespace);	/* service */
107	if (service == 0 || *service == '#')
108	    continue;
109	if (STR_NE(service, "stream") && STR_NE(service, "dgram"))
110	    strtok((char *) 0, whitespace);	/* endpoint */
111	protocol = strtok((char *) 0, whitespace);
112	(void) strtok((char *) 0, whitespace);	/* wait */
113	if ((user = strtok((char *) 0, whitespace)) == 0)
114	    continue;
115	if (user[0] == '/') {			/* user */
116	    path = user;
117	} else {				/* path */
118	    if ((path = strtok((char *) 0, whitespace)) == 0)
119		continue;
120	}
121	if (path[0] == '?')			/* IRIX optional service */
122	    path++;
123	if (STR_EQ(path, "internal"))
124	    continue;
125	if (path[strspn(path, "-0123456789")] == 0) {
126
127	    /*
128	     * ConvexOS puts RPC version numbers before path names. Jukka
129	     * Ukkonen <ukkonen@csc.fi>.
130	     */
131	    if ((path = strtok((char *) 0, whitespace)) == 0)
132		continue;
133	}
134	if ((arg0 = strtok((char *) 0, whitespace)) == 0) {
135	    tcpd_warn("incomplete line");
136	    continue;
137	}
138	if (arg0[strspn(arg0, "0123456789")] == 0) {
139
140	    /*
141	     * We're reading a tlid.conf file, the format is:
142	     *
143	     * ...stuff... path arg_count arguments mod_count modules
144	     */
145	    if ((arg0 = strtok((char *) 0, whitespace)) == 0) {
146		tcpd_warn("incomplete line");
147		continue;
148	    }
149	}
150	if ((arg1 = strtok((char *) 0, whitespace)) == 0)
151	    arg1 = "";
152
153	inet_chk(protocol, path, arg0, arg1);
154    }
155    fclose(fp);
156    tcpd_context = saved_context;
157    return (conf);
158}
159
160/* inet_chk - examine one inetd.conf (tlid.conf?) entry */
161
162static void inet_chk(protocol, path, arg0, arg1)
163char   *protocol;
164char   *path;
165char   *arg0;
166char   *arg1;
167{
168    char    daemon[BUFSIZ];
169    struct stat st;
170    int     wrap_status = WR_MAYBE;
171    char   *base_name_path = base_name(path);
172    char   *tcpd_proc_name = (arg0[0] == '/' ? base_name(arg0) : arg0);
173
174    /*
175     * Always warn when the executable does not exist or when it is not
176     * executable.
177     */
178    if (check_path(path, &st) < 0) {
179	tcpd_warn("%s: not found: %m", path);
180    } else if ((st.st_mode & 0100) == 0) {
181	tcpd_warn("%s: not executable", path);
182    }
183
184    /*
185     * Cheat on the miscd tests, nobody uses it anymore.
186     */
187    if (STR_EQ(base_name_path, "miscd")) {
188	inet_set(arg0, WR_YES);
189	return;
190    }
191
192    /*
193     * While we are here...
194     */
195    if (STR_EQ(tcpd_proc_name, "rexd") || STR_EQ(tcpd_proc_name, "rpc.rexd"))
196	tcpd_warn("%s may be an insecure service", tcpd_proc_name);
197
198    /*
199     * The tcpd program gets most of the attention.
200     */
201    if (STR_EQ(base_name_path, "tcpd")) {
202
203	if (STR_EQ(tcpd_proc_name, "tcpd"))
204	    tcpd_warn("%s is recursively calling itself", tcpd_proc_name);
205
206	wrap_status = WR_YES;
207
208	/*
209	 * Check: some sites install the wrapper set-uid.
210	 */
211	if ((st.st_mode & 06000) != 0)
212	    tcpd_warn("%s: file is set-uid or set-gid", path);
213
214	/*
215	 * Check: some sites insert tcpd in inetd.conf, instead of replacing
216	 * the daemon pathname.
217	 */
218	if (arg0[0] == '/' && STR_EQ(tcpd_proc_name, base_name(arg1)))
219	    tcpd_warn("%s inserted before %s", path, arg0);
220
221	/*
222	 * Check: make sure files exist and are executable. On some systems
223	 * the network daemons are set-uid so we cannot complain. Note that
224	 * tcpd takes the basename only in case of absolute pathnames.
225	 */
226	if (arg0[0] == '/') {			/* absolute path */
227	    if (check_path(arg0, &st) < 0) {
228		tcpd_warn("%s: not found: %m", arg0);
229	    } else if ((st.st_mode & 0100) == 0) {
230		tcpd_warn("%s: not executable", arg0);
231	    }
232	} else {				/* look in REAL_DAEMON_DIR */
233	    sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0);
234	    if (check_path(daemon, &st) < 0) {
235		tcpd_warn("%s: not found in %s: %m",
236			  arg0, REAL_DAEMON_DIR);
237	    } else if ((st.st_mode & 0100) == 0) {
238		tcpd_warn("%s: not executable", daemon);
239	    }
240	}
241
242    } else {
243
244	/*
245	 * No tcpd program found. Perhaps they used the "simple installation"
246	 * recipe. Look for a file with the same basename in REAL_DAEMON_DIR.
247	 * Draw some conservative conclusions when a distinct file is found.
248	 */
249	sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0);
250	if (STR_EQ(path, daemon)) {
251#ifdef __FreeBSD__
252	    wrap_status = WR_MAYBE;
253#else
254	    wrap_status = WR_NOT;
255#endif
256	} else if (check_path(daemon, &st) >= 0) {
257	    wrap_status = WR_MAYBE;
258	} else if (errno == ENOENT) {
259	    wrap_status = WR_NOT;
260	} else {
261	    tcpd_warn("%s: file lookup: %m", daemon);
262	    wrap_status = WR_MAYBE;
263	}
264    }
265
266    /*
267     * Alas, we cannot wrap rpc/tcp services.
268     */
269    if (wrap_status == WR_YES && STR_EQ(protocol, "rpc/tcp"))
270	tcpd_warn("%s: cannot wrap rpc/tcp services", tcpd_proc_name);
271
272    inet_set(tcpd_proc_name, wrap_status);
273}
274
275/* inet_set - remember service status */
276
277void    inet_set(name, type)
278char   *name;
279int     type;
280{
281    struct inet_ent *ip =
282    (struct inet_ent *) malloc(sizeof(struct inet_ent) + strlen(name));
283
284    if (ip == 0) {
285	fprintf(stderr, "out of memory\n");
286	exit(1);
287    }
288    ip->next = inet_list;
289    strcpy(ip->name, name);
290    ip->type = type;
291    inet_list = ip;
292}
293
294/* inet_get - look up service status */
295
296int     inet_get(name)
297char   *name;
298{
299    struct inet_ent *ip;
300
301    if (inet_list == 0)
302	return (WR_MAYBE);
303
304    for (ip = inet_list; ip; ip = ip->next)
305	if (STR_EQ(ip->name, name))
306	    return (ip->type);
307
308    return (-1);
309}
310
311/* base_name - compute last pathname component */
312
313static char *base_name(path)
314char   *path;
315{
316    char   *cp;
317
318    if ((cp = strrchr(path, '/')) != 0)
319	path = cp + 1;
320    return (path);
321}
322