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