source: branches/samba-3.3.x/source/lib/access.c

Last change on this file was 206, checked in by Herwig Bauernfeind, 16 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 10.5 KB
RevLine 
[206]1/*
2 This module is an adaption of code from the tcpd-1.4 package written
3 by Wietse Venema, Eindhoven University of Technology, The Netherlands.
4
5 The code is used here with permission.
6
7 The code has been considerably changed from the original. Bug reports
8 should be sent to samba@samba.org
9
10 Updated for IPv6 by Jeremy Allison (C) 2007.
11*/
12
13#include "includes.h"
14
15#define NAME_INDEX 0
16#define ADDR_INDEX 1
17
18/* masked_match - match address against netnumber/netmask */
19static bool masked_match(const char *tok, const char *slash, const char *s)
20{
21 struct sockaddr_storage ss_mask;
22 struct sockaddr_storage ss_tok;
23 struct sockaddr_storage ss_host;
24 char *tok_copy = NULL;
25
26 if (!interpret_string_addr(&ss_host, s, 0)) {
27 return false;
28 }
29
30 if (*tok == '[') {
31 /* IPv6 address - remove braces. */
32 tok_copy = SMB_STRDUP(tok+1);
33 if (!tok_copy) {
34 return false;
35 }
36 /* Remove the terminating ']' */
37 tok_copy[PTR_DIFF(slash,tok)-1] = '\0';
38 } else {
39 tok_copy = SMB_STRDUP(tok);
40 if (!tok_copy) {
41 return false;
42 }
43 /* Remove the terminating '/' */
44 tok_copy[PTR_DIFF(slash,tok)] = '\0';
45 }
46
47 if (!interpret_string_addr(&ss_tok, tok_copy, 0)) {
48 SAFE_FREE(tok_copy);
49 return false;
50 }
51
52 SAFE_FREE(tok_copy);
53
54 if (strlen(slash + 1) > 2) {
55 if (!interpret_string_addr(&ss_mask, slash+1, 0)) {
56 return false;
57 }
58 } else {
59 char *endp = NULL;
60 unsigned long val = strtoul(slash+1, &endp, 0);
61 if (slash+1 == endp || (endp && *endp != '\0')) {
62 return false;
63 }
64 if (!make_netmask(&ss_mask, &ss_tok, val)) {
65 return false;
66 }
67 }
68
69 return same_net(&ss_host, &ss_tok, &ss_mask);
70}
71
72/* string_match - match string s against token tok */
73static bool string_match(const char *tok,const char *s)
74{
75 size_t tok_len;
76 size_t str_len;
77 const char *cut;
78
79 /* Return true if a token has the magic value "ALL". Return
80 * true if the token is "FAIL". If the token starts with a "."
81 * (domain name), return true if it matches the last fields of
82 * the string. If the token has the magic value "LOCAL",
83 * return true if the string does not contain a "."
84 * character. If the token ends on a "." (network number),
85 * return true if it matches the first fields of the
86 * string. If the token begins with a "@" (netgroup name),
87 * return true if the string is a (host) member of the
88 * netgroup. Return true if the token fully matches the
89 * string. If the token is a netnumber/netmask pair, return
90 * true if the address is a member of the specified subnet.
91 */
92
93 if (tok[0] == '.') { /* domain: match last fields */
94 if ((str_len = strlen(s)) > (tok_len = strlen(tok))
95 && strequal(tok, s + str_len - tok_len)) {
96 return true;
97 }
98 } else if (tok[0] == '@') { /* netgroup: look it up */
99#ifdef HAVE_NETGROUP
100 DATA_BLOB tmp;
101 char *mydomain = NULL;
102 char *hostname = NULL;
103 bool netgroup_ok = false;
104
105 if (memcache_lookup(
106 NULL, SINGLETON_CACHE,
107 data_blob_string_const("yp_default_domain"),
108 &tmp)) {
109
110 SMB_ASSERT(tmp.length > 0);
111 mydomain = (tmp.data[0] == '\0')
112 ? NULL : (char *)tmp.data;
113 }
114 else {
115 yp_get_default_domain(&mydomain);
116
117 memcache_add(
118 NULL, SINGLETON_CACHE,
119 data_blob_string_const("yp_default_domain"),
120 data_blob_string_const(mydomain?mydomain:""));
121 }
122
123 if (!mydomain) {
124 DEBUG(0,("Unable to get default yp domain. "
125 "Try without it.\n"));
126 }
127 if (!(hostname = SMB_STRDUP(s))) {
128 DEBUG(1,("out of memory for strdup!\n"));
129 return false;
130 }
131
132 netgroup_ok = innetgr(tok + 1, hostname, (char *) 0, mydomain);
133
134 DEBUG(5,("looking for %s of domain %s in netgroup %s gave %s\n",
135 hostname,
136 mydomain?mydomain:"(ANY)",
137 tok+1,
138 BOOLSTR(netgroup_ok)));
139
140 SAFE_FREE(hostname);
141
142 if (netgroup_ok)
143 return true;
144#else
145 DEBUG(0,("access: netgroup support is not configured\n"));
146 return false;
147#endif
148 } else if (strequal(tok, "ALL")) { /* all: match any */
149 return true;
150 } else if (strequal(tok, "FAIL")) { /* fail: match any */
151 return true;
152 } else if (strequal(tok, "LOCAL")) { /* local: no dots */
153 if (strchr_m(s, '.') == 0 && !strequal(s, "unknown")) {
154 return true;
155 }
156 } else if (strequal(tok, s)) { /* match host name or address */
157 return true;
158 } else if (tok[(tok_len = strlen(tok)) - 1] == '.') { /* network */
159 if (strncmp(tok, s, tok_len) == 0) {
160 return true;
161 }
162 } else if ((cut = strchr_m(tok, '/')) != 0) { /* netnumber/netmask */
163 if ((isdigit(s[0]) && strchr_m(tok, '.') != NULL) ||
164 (tok[0] == '[' && cut > tok && cut[-1] == ']') ||
165 ((isxdigit(s[0]) || s[0] == ':') &&
166 strchr_m(tok, ':') != NULL)) {
167 /* IPv4/netmask or
168 * [IPv6:addr]/netmask or IPv6:addr/netmask */
169 return masked_match(tok, cut, s);
170 }
171 } else if (strchr_m(tok, '*') != 0 || strchr_m(tok, '?')) {
172 return unix_wild_match(tok, s);
173 }
174 return false;
175}
176
177/* client_match - match host name and address against token */
178bool client_match(const char *tok, const void *item)
179{
180 const char **client = (const char **)item;
181
182 /*
183 * Try to match the address first. If that fails, try to match the host
184 * name if available.
185 */
186
187 if (string_match(tok, client[ADDR_INDEX])) {
188 return true;
189 }
190
191 if (strnequal(client[ADDR_INDEX],"::ffff:",7) &&
192 !strnequal(tok, "::ffff:",7)) {
193 /* client[ADDR_INDEX] is an IPv4 mapped to IPv6, but
194 * the list item is not. Try and match the IPv4 part of
195 * address only. This will happen a lot on IPv6 enabled
196 * systems with IPv4 allow/deny lists in smb.conf.
197 * Bug #5311. JRA.
198 */
199 if (string_match(tok, (client[ADDR_INDEX])+7)) {
200 return true;
201 }
202 }
203
204 if (client[NAME_INDEX][0] != 0) {
205 if (string_match(tok, client[NAME_INDEX])) {
206 return true;
207 }
208 }
209
210 return false;
211}
212
213/* list_match - match an item against a list of tokens with exceptions */
214bool list_match(const char **list,const void *item,
215 bool (*match_fn)(const char *, const void *))
216{
217 bool match = false;
218
219 if (!list) {
220 return false;
221 }
222
223 /*
224 * Process tokens one at a time. We have exhausted all possible matches
225 * when we reach an "EXCEPT" token or the end of the list. If we do find
226 * a match, look for an "EXCEPT" list and recurse to determine whether
227 * the match is affected by any exceptions.
228 */
229
230 for (; *list ; list++) {
231 if (strequal(*list, "EXCEPT")) {
232 /* EXCEPT: give up */
233 break;
234 }
235 if ((match = (*match_fn) (*list, item))) {
236 /* true or FAIL */
237 break;
238 }
239 }
240 /* Process exceptions to true or FAIL matches. */
241
242 if (match != false) {
243 while (*list && !strequal(*list, "EXCEPT")) {
244 list++;
245 }
246
247 for (; *list; list++) {
248 if ((*match_fn) (*list, item)) {
249 /* Exception Found */
250 return false;
251 }
252 }
253 }
254
255 return match;
256}
257
258/* return true if access should be allowed */
259static bool allow_access_internal(const char **deny_list,
260 const char **allow_list,
261 const char *cname,
262 const char *caddr)
263{
264 const char *client[2];
265
266 client[NAME_INDEX] = cname;
267 client[ADDR_INDEX] = caddr;
268
269 /* if it is loopback then always allow unless specifically denied */
270 if (strcmp(caddr, "127.0.0.1") == 0 || strcmp(caddr, "::1") == 0) {
271 /*
272 * If 127.0.0.1 matches both allow and deny then allow.
273 * Patch from Steve Langasek vorlon@netexpress.net.
274 */
275 if (deny_list &&
276 list_match(deny_list,client,client_match) &&
277 (!allow_list ||
278 !list_match(allow_list,client, client_match))) {
279 return false;
280 }
281 return true;
282 }
283
284 /* if theres no deny list and no allow list then allow access */
285 if ((!deny_list || *deny_list == 0) &&
286 (!allow_list || *allow_list == 0)) {
287 return true;
288 }
289
290 /* if there is an allow list but no deny list then allow only hosts
291 on the allow list */
292 if (!deny_list || *deny_list == 0) {
293 return(list_match(allow_list,client,client_match));
294 }
295
296 /* if theres a deny list but no allow list then allow
297 all hosts not on the deny list */
298 if (!allow_list || *allow_list == 0) {
299 return(!list_match(deny_list,client,client_match));
300 }
301
302 /* if there are both types of list then allow all hosts on the
303 allow list */
304 if (list_match(allow_list,(const char *)client,client_match)) {
305 return true;
306 }
307
308 /* if there are both types of list and it's not on the allow then
309 allow it if its not on the deny */
310 if (list_match(deny_list,(const char *)client,client_match)) {
311 return false;
312 }
313
314 return true;
315}
316
317/* return true if access should be allowed */
318bool allow_access(const char **deny_list,
319 const char **allow_list,
320 const char *cname,
321 const char *caddr)
322{
323 bool ret;
324 char *nc_cname = smb_xstrdup(cname);
325 char *nc_caddr = smb_xstrdup(caddr);
326
327 ret = allow_access_internal(deny_list, allow_list, nc_cname, nc_caddr);
328
329 SAFE_FREE(nc_cname);
330 SAFE_FREE(nc_caddr);
331 return ret;
332}
333
334/* return true if the char* contains ip addrs only. Used to avoid
335name lookup calls */
336
337static bool only_ipaddrs_in_list(const char **list)
338{
339 bool only_ip = true;
340
341 if (!list) {
342 return true;
343 }
344
345 for (; *list ; list++) {
346 /* factor out the special strings */
347 if (strequal(*list, "ALL") || strequal(*list, "FAIL") ||
348 strequal(*list, "EXCEPT")) {
349 continue;
350 }
351
352 if (!is_ipaddress(*list)) {
353 /*
354 * If we failed, make sure that it was not because
355 * the token was a network/netmask pair. Only
356 * network/netmask pairs have a '/' in them.
357 */
358 if ((strchr_m(*list, '/')) == NULL) {
359 only_ip = false;
360 DEBUG(3,("only_ipaddrs_in_list: list has "
361 "non-ip address (%s)\n",
362 *list));
363 break;
364 }
365 }
366 }
367
368 return only_ip;
369}
370
371/* return true if access should be allowed to a service for a socket */
372bool check_access(int sock, const char **allow_list, const char **deny_list)
373{
374 bool ret = false;
375 bool only_ip = false;
376
377 if ((!deny_list || *deny_list==0) && (!allow_list || *allow_list==0))
378 ret = true;
379
380 if (!ret) {
381 char addr[INET6_ADDRSTRLEN];
382
383 /* Bypass name resolution calls if the lists
384 * only contain IP addrs */
385 if (only_ipaddrs_in_list(allow_list) &&
386 only_ipaddrs_in_list(deny_list)) {
387 only_ip = true;
388 DEBUG (3, ("check_access: no hostnames "
389 "in host allow/deny list.\n"));
390 ret = allow_access(deny_list,
391 allow_list,
392 "",
393 get_peer_addr(sock,addr,sizeof(addr)));
394 } else {
395 DEBUG (3, ("check_access: hostnames in "
396 "host allow/deny list.\n"));
397 ret = allow_access(deny_list,
398 allow_list,
399 get_peer_name(sock,true),
400 get_peer_addr(sock,addr,sizeof(addr)));
401 }
402
403 if (ret) {
404 DEBUG(2,("Allowed connection from %s (%s)\n",
405 only_ip ? "" : get_peer_name(sock,true),
406 get_peer_addr(sock,addr,sizeof(addr))));
407 } else {
408 DEBUG(0,("Denied connection from %s (%s)\n",
409 only_ip ? "" : get_peer_name(sock,true),
410 get_peer_addr(sock,addr,sizeof(addr))));
411 }
412 }
413
414 return(ret);
415}
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