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