1 /*
2  * tcpdchk - examine all tcpd access control rules and inetd.conf entries
3  *
4  * Usage: tcpdchk [-a] [-d] [-i inet_conf] [-v]
5  *
6  * -a: complain about implicit "allow" at end of rule.
7  *
8  * -d: rules in current directory.
9  *
10  * -i: location of inetd.conf file.
11  *
12  * -v: show all rules.
13  *
14  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
15  *
16  * $FreeBSD$
17  */
18
19#ifndef lint
20static char sccsid[] = "@(#) tcpdchk.c 1.8 97/02/12 02:13:25";
21#endif
22
23/* System libraries. */
24
25#include <sys/types.h>
26#include <sys/stat.h>
27#ifdef INET6
28#include <sys/socket.h>
29#endif
30#include <netinet/in.h>
31#include <arpa/inet.h>
32#include <stdio.h>
33#include <syslog.h>
34#include <setjmp.h>
35#include <errno.h>
36#include <netdb.h>
37#include <string.h>
38
39extern int errno;
40extern void exit();
41extern int optind;
42extern char *optarg;
43
44#ifndef INADDR_NONE
45#define INADDR_NONE     (-1)		/* XXX should be 0xffffffff */
46#endif
47
48#ifndef S_ISDIR
49#define S_ISDIR(m)	(((m) & S_IFMT) == S_IFDIR)
50#endif
51
52/* Application-specific. */
53
54#include "tcpd.h"
55#include "inetcf.h"
56#include "scaffold.h"
57
58 /*
59  * Stolen from hosts_access.c...
60  */
61static char sep[] = ", \t\n";
62
63#define	BUFLEN 2048
64
65int     resident = 0;
66int     hosts_access_verbose = 0;
67char   *hosts_allow_table = HOSTS_ALLOW;
68char   *hosts_deny_table = HOSTS_DENY;
69extern jmp_buf tcpd_buf;
70
71 /*
72  * Local stuff.
73  */
74static void usage();
75static void parse_table();
76static void print_list();
77static void check_daemon_list();
78static void check_client_list();
79static void check_daemon();
80static void check_user();
81static int check_host();
82static int reserved_name();
83
84#define PERMIT	1
85#define DENY	0
86
87#define YES	1
88#define	NO	0
89
90static int defl_verdict;
91static char *myname;
92static int allow_check;
93static char *inetcf;
94
95int     main(argc, argv)
96int     argc;
97char  **argv;
98{
99    struct request_info request;
100    struct stat st;
101    int     c;
102
103    myname = argv[0];
104
105    /*
106     * Parse the JCL.
107     */
108    while ((c = getopt(argc, argv, "adi:v")) != EOF) {
109	switch (c) {
110	case 'a':
111	    allow_check = 1;
112	    break;
113	case 'd':
114	    hosts_allow_table = "hosts.allow";
115	    hosts_deny_table = "hosts.deny";
116	    break;
117	case 'i':
118	    inetcf = optarg;
119	    break;
120	case 'v':
121	    hosts_access_verbose++;
122	    break;
123	default:
124	    usage();
125	    /* NOTREACHED */
126	}
127    }
128    if (argc != optind)
129	usage();
130
131    /*
132     * When confusion really strikes...
133     */
134    if (check_path(REAL_DAEMON_DIR, &st) < 0) {
135	tcpd_warn("REAL_DAEMON_DIR %s: %m", REAL_DAEMON_DIR);
136    } else if (!S_ISDIR(st.st_mode)) {
137	tcpd_warn("REAL_DAEMON_DIR %s is not a directory", REAL_DAEMON_DIR);
138    }
139
140    /*
141     * Process the inet configuration file (or its moral equivalent). This
142     * information is used later to find references in hosts.allow/deny to
143     * unwrapped services, and other possible problems.
144     */
145    inetcf = inet_cfg(inetcf);
146    if (hosts_access_verbose)
147	printf("Using network configuration file: %s\n", inetcf);
148
149    /*
150     * These are not run from inetd but may have built-in access control.
151     */
152    inet_set("portmap", WR_NOT);
153    inet_set("rpcbind", WR_NOT);
154
155    /*
156     * Check accessibility of access control files.
157     */
158    (void) check_path(hosts_allow_table, &st);
159    (void) check_path(hosts_deny_table, &st);
160
161    /*
162     * Fake up an arbitrary service request.
163     */
164    request_init(&request,
165		 RQ_DAEMON, "daemon_name",
166		 RQ_SERVER_NAME, "server_hostname",
167		 RQ_SERVER_ADDR, "server_addr",
168		 RQ_USER, "user_name",
169		 RQ_CLIENT_NAME, "client_hostname",
170		 RQ_CLIENT_ADDR, "client_addr",
171		 RQ_FILE, 1,
172		 0);
173
174    /*
175     * Examine all access-control rules.
176     */
177    defl_verdict = PERMIT;
178    parse_table(hosts_allow_table, &request);
179    defl_verdict = DENY;
180    parse_table(hosts_deny_table, &request);
181    return (0);
182}
183
184/* usage - explain */
185
186static void usage()
187{
188    fprintf(stderr, "usage: %s [-a] [-d] [-i inet_conf] [-v]\n", myname);
189    fprintf(stderr, "	-a: report rules with implicit \"ALLOW\" at end\n");
190    fprintf(stderr, "	-d: use allow/deny files in current directory\n");
191    fprintf(stderr, "	-i: location of inetd.conf file\n");
192    fprintf(stderr, "	-v: list all rules\n");
193    exit(1);
194}
195
196/* parse_table - like table_match(), but examines _all_ entries */
197
198static void parse_table(table, request)
199char   *table;
200struct request_info *request;
201{
202    FILE   *fp;
203    int     real_verdict;
204    char    sv_list[BUFLEN];		/* becomes list of daemons */
205    char   *cl_list;			/* becomes list of requests */
206    char   *sh_cmd;			/* becomes optional shell command */
207    char    buf[BUFSIZ];
208    int     verdict;
209    struct tcpd_context saved_context;
210
211    saved_context = tcpd_context;		/* stupid compilers */
212
213    if (fp = fopen(table, "r")) {
214	tcpd_context.file = table;
215	tcpd_context.line = 0;
216	while (xgets(sv_list, sizeof(sv_list), fp)) {
217	    if (sv_list[strlen(sv_list) - 1] != '\n') {
218		tcpd_warn("missing newline or line too long");
219		continue;
220	    }
221	    if (sv_list[0] == '#' || sv_list[strspn(sv_list, " \t\r\n")] == 0)
222		continue;
223	    if ((cl_list = split_at(sv_list, ':')) == 0) {
224		tcpd_warn("missing \":\" separator");
225		continue;
226	    }
227	    sh_cmd = split_at(cl_list, ':');
228
229	    if (hosts_access_verbose)
230		printf("\n>>> Rule %s line %d:\n",
231		       tcpd_context.file, tcpd_context.line);
232
233	    if (hosts_access_verbose)
234		print_list("daemons:  ", sv_list);
235	    check_daemon_list(sv_list);
236
237	    if (hosts_access_verbose)
238		print_list("clients:  ", cl_list);
239	    check_client_list(cl_list);
240
241#ifdef PROCESS_OPTIONS
242	    real_verdict = defl_verdict;
243	    if (sh_cmd) {
244		verdict = setjmp(tcpd_buf);
245		if (verdict != 0) {
246		    real_verdict = (verdict == AC_PERMIT);
247		} else {
248		    dry_run = 1;
249		    process_options(sh_cmd, request);
250		    if (dry_run == 1 && real_verdict && allow_check)
251			tcpd_warn("implicit \"allow\" at end of rule");
252		}
253	    } else if (defl_verdict && allow_check) {
254		tcpd_warn("implicit \"allow\" at end of rule");
255	    }
256	    if (hosts_access_verbose)
257		printf("access:   %s\n", real_verdict ? "granted" : "denied");
258#else
259	    if (sh_cmd)
260		shell_cmd(percent_x(buf, sizeof(buf), sh_cmd, request));
261	    if (hosts_access_verbose)
262		printf("access:   %s\n", defl_verdict ? "granted" : "denied");
263#endif
264	}
265	(void) fclose(fp);
266    } else if (errno != ENOENT) {
267	tcpd_warn("cannot open %s: %m", table);
268    }
269    tcpd_context = saved_context;
270}
271
272/* print_list - pretty-print a list */
273
274static void print_list(title, list)
275char   *title;
276char   *list;
277{
278    char    buf[BUFLEN];
279    char   *cp;
280    char   *next;
281
282    fputs(title, stdout);
283    strcpy(buf, list);
284
285    for (cp = strtok(buf, sep); cp != 0; cp = next) {
286	fputs(cp, stdout);
287	next = strtok((char *) 0, sep);
288	if (next != 0)
289	    fputs(" ", stdout);
290    }
291    fputs("\n", stdout);
292}
293
294/* check_daemon_list - criticize daemon list */
295
296static void check_daemon_list(list)
297char   *list;
298{
299    char    buf[BUFLEN];
300    char   *cp;
301    char   *host;
302    int     daemons = 0;
303
304    strcpy(buf, list);
305
306    for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
307	if (STR_EQ(cp, "EXCEPT")) {
308	    daemons = 0;
309	} else {
310	    daemons++;
311	    if ((host = split_at(cp + 1, '@')) != 0 && check_host(host) > 1) {
312		tcpd_warn("host %s has more than one address", host);
313		tcpd_warn("(consider using an address instead)");
314	    }
315	    check_daemon(cp);
316	}
317    }
318    if (daemons == 0)
319	tcpd_warn("daemon list is empty or ends in EXCEPT");
320}
321
322/* check_client_list - criticize client list */
323
324static void check_client_list(list)
325char   *list;
326{
327    char    buf[BUFLEN];
328    char   *cp;
329    char   *host;
330    int     clients = 0;
331
332    strcpy(buf, list);
333
334    for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
335	if (STR_EQ(cp, "EXCEPT")) {
336	    clients = 0;
337	} else {
338	    clients++;
339	    if (host = split_at(cp + 1, '@')) {	/* user@host */
340		check_user(cp);
341		check_host(host);
342	    } else {
343		check_host(cp);
344	    }
345	}
346    }
347    if (clients == 0)
348	tcpd_warn("client list is empty or ends in EXCEPT");
349}
350
351/* check_daemon - criticize daemon pattern */
352
353static void check_daemon(pat)
354char   *pat;
355{
356    if (pat[0] == '@') {
357	tcpd_warn("%s: daemon name begins with \"@\"", pat);
358    } else if (pat[0] == '/') {
359	tcpd_warn("%s: daemon name begins with \"/\"", pat);
360    } else if (pat[0] == '.') {
361	tcpd_warn("%s: daemon name begins with dot", pat);
362    } else if (pat[strlen(pat) - 1] == '.') {
363	tcpd_warn("%s: daemon name ends in dot", pat);
364    } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)) {
365	 /* void */ ;
366    } else if (STR_EQ(pat, "FAIL")) {		/* obsolete */
367	tcpd_warn("FAIL is no longer recognized");
368	tcpd_warn("(use EXCEPT or DENY instead)");
369    } else if (reserved_name(pat)) {
370	tcpd_warn("%s: daemon name may be reserved word", pat);
371    } else {
372	switch (inet_get(pat)) {
373	case WR_UNKNOWN:
374	    tcpd_warn("%s: no such process name in %s", pat, inetcf);
375	    inet_set(pat, WR_YES);		/* shut up next time */
376	    break;
377	case WR_NOT:
378	    tcpd_warn("%s: service possibly not wrapped", pat);
379	    inet_set(pat, WR_YES);
380	    break;
381	}
382    }
383}
384
385/* check_user - criticize user pattern */
386
387static void check_user(pat)
388char   *pat;
389{
390    if (pat[0] == '@') {			/* @netgroup */
391	tcpd_warn("%s: user name begins with \"@\"", pat);
392    } else if (pat[0] == '/') {
393	tcpd_warn("%s: user name begins with \"/\"", pat);
394    } else if (pat[0] == '.') {
395	tcpd_warn("%s: user name begins with dot", pat);
396    } else if (pat[strlen(pat) - 1] == '.') {
397	tcpd_warn("%s: user name ends in dot", pat);
398    } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)
399	       || STR_EQ(pat, "KNOWN")) {
400	 /* void */ ;
401    } else if (STR_EQ(pat, "FAIL")) {		/* obsolete */
402	tcpd_warn("FAIL is no longer recognized");
403	tcpd_warn("(use EXCEPT or DENY instead)");
404    } else if (reserved_name(pat)) {
405	tcpd_warn("%s: user name may be reserved word", pat);
406    }
407}
408
409#ifdef INET6
410static int is_inet6_addr(pat)
411    char *pat;
412{
413    struct addrinfo hints, *res;
414    int len, ret;
415    char ch;
416
417    if (*pat != '[')
418	return (0);
419    len = strlen(pat);
420    if ((ch = pat[len - 1]) != ']')
421	return (0);
422    pat[len - 1] = '\0';
423    memset(&hints, 0, sizeof(hints));
424    hints.ai_family = AF_INET6;
425    hints.ai_socktype = SOCK_STREAM;
426    hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
427    if ((ret = getaddrinfo(pat + 1, NULL, &hints, &res)) == 0)
428	freeaddrinfo(res);
429    pat[len - 1] = ch;
430    return (ret == 0);
431}
432#endif
433
434/* check_host - criticize host pattern */
435
436static int check_host(pat)
437char   *pat;
438{
439    char    buf[BUFSIZ];
440    char   *mask;
441    int     addr_count = 1;
442    FILE   *fp;
443    struct tcpd_context saved_context;
444    char   *cp;
445    char   *wsp = " \t\r\n";
446
447    if (pat[0] == '@') {			/* @netgroup */
448#ifdef NO_NETGRENT
449	/* SCO has no *netgrent() support */
450#else
451#ifdef NETGROUP
452	char   *machinep;
453	char   *userp;
454	char   *domainp;
455
456	setnetgrent(pat + 1);
457	if (getnetgrent(&machinep, &userp, &domainp) == 0)
458	    tcpd_warn("%s: unknown or empty netgroup", pat + 1);
459	endnetgrent();
460#else
461	tcpd_warn("netgroup support disabled");
462#endif
463#endif
464    } else if (pat[0] == '/') {			/* /path/name */
465	if ((fp = fopen(pat, "r")) != 0) {
466	    saved_context = tcpd_context;
467	    tcpd_context.file = pat;
468	    tcpd_context.line = 0;
469	    while (fgets(buf, sizeof(buf), fp)) {
470		tcpd_context.line++;
471		for (cp = strtok(buf, wsp); cp; cp = strtok((char *) 0, wsp))
472		    check_host(cp);
473	    }
474	    tcpd_context = saved_context;
475	    fclose(fp);
476	} else if (errno != ENOENT) {
477	    tcpd_warn("open %s: %m", pat);
478	}
479    } else if (mask = split_at(pat, '/')) {	/* network/netmask */
480#ifdef INET6
481	int mask_len;
482
483	if ((dot_quad_addr(pat) == INADDR_NONE
484	    || dot_quad_addr(mask) == INADDR_NONE)
485	    && (!is_inet6_addr(pat)
486		|| ((mask_len = atoi(mask)) < 0 || mask_len > 128)))
487#else
488	if (dot_quad_addr(pat) == INADDR_NONE
489	    || dot_quad_addr(mask) == INADDR_NONE)
490#endif
491	    tcpd_warn("%s/%s: bad net/mask pattern", pat, mask);
492    } else if (STR_EQ(pat, "FAIL")) {		/* obsolete */
493	tcpd_warn("FAIL is no longer recognized");
494	tcpd_warn("(use EXCEPT or DENY instead)");
495    } else if (reserved_name(pat)) {		/* other reserved */
496	 /* void */ ;
497#ifdef INET6
498    } else if (is_inet6_addr(pat)) { /* IPv6 address */
499	addr_count = 1;
500#endif
501    } else if (NOT_INADDR(pat)) {		/* internet name */
502	if (pat[strlen(pat) - 1] == '.') {
503	    tcpd_warn("%s: domain or host name ends in dot", pat);
504	} else if (pat[0] != '.') {
505	    addr_count = check_dns(pat);
506	}
507    } else {					/* numeric form */
508	if (STR_EQ(pat, "0.0.0.0") || STR_EQ(pat, "255.255.255.255")) {
509	    /* void */ ;
510	} else if (pat[0] == '.') {
511	    tcpd_warn("%s: network number begins with dot", pat);
512	} else if (pat[strlen(pat) - 1] != '.') {
513	    check_dns(pat);
514	}
515    }
516    return (addr_count);
517}
518
519/* reserved_name - determine if name is reserved */
520
521static int reserved_name(pat)
522char   *pat;
523{
524    return (STR_EQ(pat, unknown)
525	    || STR_EQ(pat, "KNOWN")
526	    || STR_EQ(pat, paranoid)
527	    || STR_EQ(pat, "ALL")
528	    || STR_EQ(pat, "LOCAL"));
529}
530