source: branches/samba-3.0/source/lib/access.c@ 621

Last change on this file since 621 was 1, checked in by Paul Smedley, 19 years ago

Initial code import
File size: 9.3 KB
Line 
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
11#include "includes.h"
12
13#define FAIL (-1)
14
15#define ALLONES ((uint32)0xFFFFFFFF)
16
17/* masked_match - match address against netnumber/netmask */
18static BOOL masked_match(const char *tok, const char *slash, const char *s)
19{
20 uint32 net;
21 uint32 mask;
22 uint32 addr;
23 fstring tok_cpy;
24
25 if ((addr = interpret_addr(s)) == INADDR_NONE)
26 return (False);
27
28 fstrcpy(tok_cpy, tok);
29 tok_cpy[PTR_DIFF(slash,tok)] = '\0';
30 net = interpret_addr(tok_cpy);
31 tok_cpy[PTR_DIFF(slash,tok)] = '/';
32
33 if (strlen(slash + 1) > 2) {
34 mask = interpret_addr(slash + 1);
35 } else {
36 mask = (uint32)((ALLONES >> atoi(slash + 1)) ^ ALLONES);
37 /* convert to network byte order */
38 mask = htonl(mask);
39 }
40
41 if (net == INADDR_NONE || mask == INADDR_NONE) {
42 DEBUG(0,("access: bad net/mask access control: %s\n", tok));
43 return (False);
44 }
45
46 return ((addr & mask) == (net & mask));
47}
48
49/* string_match - match string against token */
50static BOOL string_match(const char *tok,const char *s, char *invalid_char)
51{
52 size_t tok_len;
53 size_t str_len;
54 const char *cut;
55
56 *invalid_char = '\0';
57
58 /* Return True if a token has the magic value "ALL". Return
59 * FAIL if the token is "FAIL". If the token starts with a "."
60 * (domain name), return True if it matches the last fields of
61 * the string. If the token has the magic value "LOCAL",
62 * return True if the string does not contain a "."
63 * character. If the token ends on a "." (network number),
64 * return True if it matches the first fields of the
65 * string. If the token begins with a "@" (netgroup name),
66 * return True if the string is a (host) member of the
67 * netgroup. Return True if the token fully matches the
68 * string. If the token is a netnumber/netmask pair, return
69 * True if the address is a member of the specified subnet.
70 */
71
72 if (tok[0] == '.') { /* domain: match last fields */
73 if ((str_len = strlen(s)) > (tok_len = strlen(tok))
74 && strequal(tok, s + str_len - tok_len))
75 return (True);
76 } else if (tok[0] == '@') { /* netgroup: look it up */
77#ifdef HAVE_NETGROUP
78 static char *mydomain = NULL;
79 char *hostname = NULL;
80 BOOL netgroup_ok = False;
81
82 if (!mydomain)
83 yp_get_default_domain(&mydomain);
84
85 if (!mydomain) {
86 DEBUG(0,("Unable to get default yp domain. Try without it.\n"));
87 }
88 if (!(hostname = SMB_STRDUP(s))) {
89 DEBUG(1,("out of memory for strdup!\n"));
90 return False;
91 }
92
93 netgroup_ok = innetgr(tok + 1, hostname, (char *) 0, mydomain);
94
95 DEBUG(5,("looking for %s of domain %s in netgroup %s gave %s\n",
96 hostname,
97 mydomain?mydomain:"(ANY)",
98 tok+1,
99 BOOLSTR(netgroup_ok)));
100
101 SAFE_FREE(hostname);
102
103 if (netgroup_ok)
104 return(True);
105#else
106 DEBUG(0,("access: netgroup support is not configured\n"));
107 return (False);
108#endif
109 } else if (strequal(tok, "ALL")) { /* all: match any */
110 return (True);
111 } else if (strequal(tok, "FAIL")) { /* fail: match any */
112 return (FAIL);
113 } else if (strequal(tok, "LOCAL")) { /* local: no dots */
114 if (strchr_m(s, '.') == 0 && !strequal(s, "unknown"))
115 return (True);
116 } else if (strequal(tok, s)) { /* match host name or address */
117 return (True);
118 } else if (tok[(tok_len = strlen(tok)) - 1] == '.') { /* network */
119 if (strncmp(tok, s, tok_len) == 0)
120 return (True);
121 } else if ((cut = strchr_m(tok, '/')) != 0) { /* netnumber/netmask */
122 if (isdigit((int)s[0]) && masked_match(tok, cut, s))
123 return (True);
124 } else if (strchr_m(tok, '*') != 0) {
125 *invalid_char = '*';
126 } else if (strchr_m(tok, '?') != 0) {
127 *invalid_char = '?';
128 }
129 return (False);
130}
131
132/* client_match - match host name and address against token */
133static BOOL client_match(const char *tok, const char *item)
134{
135 const char **client = (const char **)item;
136 BOOL match;
137 char invalid_char = '\0';
138
139 /*
140 * Try to match the address first. If that fails, try to match the host
141 * name if available.
142 */
143
144 if ((match = string_match(tok, client[1], &invalid_char)) == 0) {
145 if(invalid_char)
146 DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
147token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
148
149 if (client[0][0] != 0)
150 match = string_match(tok, client[0], &invalid_char);
151
152 if(invalid_char)
153 DEBUG(0,("client_match: address match failing due to invalid character '%c' found in \
154token '%s' in an allow/deny hosts line.\n", invalid_char, tok ));
155 }
156
157 return (match);
158}
159
160/* list_match - match an item against a list of tokens with exceptions */
161static BOOL list_match(const char **list,const char *item,
162 BOOL (*match_fn)(const char *, const char *))
163{
164 BOOL match = False;
165
166 if (!list)
167 return False;
168
169 /*
170 * Process tokens one at a time. We have exhausted all possible matches
171 * when we reach an "EXCEPT" token or the end of the list. If we do find
172 * a match, look for an "EXCEPT" list and recurse to determine whether
173 * the match is affected by any exceptions.
174 */
175
176 for (; *list ; list++) {
177 if (strequal(*list, "EXCEPT")) /* EXCEPT: give up */
178 break;
179 if ((match = (*match_fn) (*list, item))) /* True or FAIL */
180 break;
181 }
182 /* Process exceptions to True or FAIL matches. */
183
184 if (match != False) {
185 while (*list && !strequal(*list, "EXCEPT"))
186 list++;
187
188 for (; *list; list++) {
189 if ((*match_fn) (*list, item)) /* Exception Found */
190 return False;
191 }
192 }
193
194 return (match);
195}
196
197/* return true if access should be allowed */
198static BOOL allow_access_internal(const char **deny_list,const char **allow_list,
199 const char *cname, const char *caddr)
200{
201 const char *client[2];
202
203 client[0] = cname;
204 client[1] = caddr;
205
206 /* if it is loopback then always allow unless specifically denied */
207 if (strcmp(caddr, "127.0.0.1") == 0) {
208 /*
209 * If 127.0.0.1 matches both allow and deny then allow.
210 * Patch from Steve Langasek vorlon@netexpress.net.
211 */
212 if (deny_list &&
213 list_match(deny_list,(const char *)client,client_match) &&
214 (!allow_list ||
215 !list_match(allow_list,(const char *)client, client_match))) {
216 return False;
217 }
218 return True;
219 }
220
221 /* if theres no deny list and no allow list then allow access */
222 if ((!deny_list || *deny_list == 0) &&
223 (!allow_list || *allow_list == 0)) {
224 return(True);
225 }
226
227 /* if there is an allow list but no deny list then allow only hosts
228 on the allow list */
229 if (!deny_list || *deny_list == 0)
230 return(list_match(allow_list,(const char *)client,client_match));
231
232 /* if theres a deny list but no allow list then allow
233 all hosts not on the deny list */
234 if (!allow_list || *allow_list == 0)
235 return(!list_match(deny_list,(const char *)client,client_match));
236
237 /* if there are both types of list then allow all hosts on the
238 allow list */
239 if (list_match(allow_list,(const char *)client,client_match))
240 return (True);
241
242 /* if there are both types of list and it's not on the allow then
243 allow it if its not on the deny */
244 if (list_match(deny_list,(const char *)client,client_match))
245 return (False);
246
247 return (True);
248}
249
250/* return true if access should be allowed */
251BOOL allow_access(const char **deny_list, const char **allow_list,
252 const char *cname, const char *caddr)
253{
254 BOOL ret;
255 char *nc_cname = smb_xstrdup(cname);
256 char *nc_caddr = smb_xstrdup(caddr);
257
258 ret = allow_access_internal(deny_list, allow_list, nc_cname, nc_caddr);
259
260 SAFE_FREE(nc_cname);
261 SAFE_FREE(nc_caddr);
262 return ret;
263}
264
265/* return true if the char* contains ip addrs only. Used to avoid
266gethostbyaddr() calls */
267
268static BOOL only_ipaddrs_in_list(const char** list)
269{
270 BOOL only_ip = True;
271
272 if (!list)
273 return True;
274
275 for (; *list ; list++) {
276 /* factor out the special strings */
277 if (strequal(*list, "ALL") || strequal(*list, "FAIL") ||
278 strequal(*list, "EXCEPT")) {
279 continue;
280 }
281
282 if (!is_ipaddress(*list)) {
283 /*
284 * if we failed, make sure that it was not because the token
285 * was a network/netmask pair. Only network/netmask pairs
286 * have a '/' in them
287 */
288 if ((strchr_m(*list, '/')) == NULL) {
289 only_ip = False;
290 DEBUG(3,("only_ipaddrs_in_list: list has non-ip address (%s)\n", *list));
291 break;
292 }
293 }
294 }
295
296 return only_ip;
297}
298
299/* return true if access should be allowed to a service for a socket */
300BOOL check_access(int sock, const char **allow_list, const char **deny_list)
301{
302 BOOL ret = False;
303 BOOL only_ip = False;
304
305 if ((!deny_list || *deny_list==0) && (!allow_list || *allow_list==0))
306 ret = True;
307
308 if (!ret) {
309 /* bypass gethostbyaddr() calls if the lists only contain IP addrs */
310 if (only_ipaddrs_in_list(allow_list) && only_ipaddrs_in_list(deny_list)) {
311 only_ip = True;
312 DEBUG (3, ("check_access: no hostnames in host allow/deny list.\n"));
313 ret = allow_access(deny_list,allow_list, "", get_peer_addr(sock));
314 } else {
315 DEBUG (3, ("check_access: hostnames in host allow/deny list.\n"));
316 ret = allow_access(deny_list,allow_list, get_peer_name(sock,True),
317 get_peer_addr(sock));
318 }
319
320 if (ret) {
321 DEBUG(2,("Allowed connection from %s (%s)\n",
322 only_ip ? "" : get_peer_name(sock,True),
323 get_peer_addr(sock)));
324 } else {
325 DEBUG(0,("Denied connection from %s (%s)\n",
326 only_ip ? "" : get_peer_name(sock,True),
327 get_peer_addr(sock)));
328 }
329 }
330
331 return(ret);
332}
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