Line data Source code
1 : /*
2 : Unix SMB/CIFS implementation.
3 : Check access based on valid users, read list and friends
4 : Copyright (C) Volker Lendecke 2005
5 :
6 : This program is free software; you can redistribute it and/or modify
7 : it under the terms of the GNU General Public License as published by
8 : the Free Software Foundation; either version 3 of the License, or
9 : (at your option) any later version.
10 :
11 : This program is distributed in the hope that it will be useful,
12 : but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : GNU General Public License for more details.
15 :
16 : You should have received a copy of the GNU General Public License
17 : along with this program. If not, see <http://www.gnu.org/licenses/>.
18 : */
19 :
20 : #include "includes.h"
21 : #include "smbd/smbd.h"
22 : #include "smbd/globals.h"
23 : #include "../libcli/security/security.h"
24 : #include "passdb/lookup_sid.h"
25 : #include "auth.h"
26 : #include "source3/lib/substitute.h"
27 :
28 : /*
29 : * No prefix means direct username
30 : * @name means netgroup first, then unix group
31 : * &name means netgroup
32 : * +name means unix group
33 : * + and & may be combined
34 : */
35 :
36 446 : static bool do_group_checks(const char **name, const char **pattern)
37 : {
38 446 : if ((*name)[0] == '@') {
39 18 : *pattern = "&+";
40 18 : *name += 1;
41 18 : return True;
42 : }
43 :
44 428 : if (((*name)[0] == '+') && ((*name)[1] == '&')) {
45 12 : *pattern = "+&";
46 12 : *name += 2;
47 12 : return True;
48 : }
49 :
50 416 : if ((*name)[0] == '+') {
51 24 : *pattern = "+";
52 24 : *name += 1;
53 24 : return True;
54 : }
55 :
56 392 : if (((*name)[0] == '&') && ((*name)[1] == '+')) {
57 12 : *pattern = "&+";
58 12 : *name += 2;
59 12 : return True;
60 : }
61 :
62 380 : if ((*name)[0] == '&') {
63 4 : *pattern = "&";
64 4 : *name += 1;
65 4 : return True;
66 : }
67 :
68 376 : return False;
69 : }
70 :
71 446 : static bool token_contains_name(TALLOC_CTX *mem_ctx,
72 : const char *username,
73 : const char *domain,
74 : const char *sharename,
75 : const struct security_token *token,
76 : const char *name)
77 : {
78 0 : const char *prefix;
79 0 : struct dom_sid sid;
80 0 : enum lsa_SidType type;
81 :
82 446 : if (username != NULL) {
83 446 : size_t domain_len = domain != NULL ? strlen(domain) : 0;
84 :
85 : /* Check if username starts with domain name */
86 446 : if (domain_len > 0) {
87 446 : const char *sep = lp_winbind_separator();
88 446 : int cmp = strncasecmp_m(username, domain, domain_len);
89 446 : if (cmp == 0 && sep[0] == username[domain_len]) {
90 : /* Move after the winbind separator */
91 156 : domain_len += 1;
92 : } else {
93 290 : domain_len = 0;
94 : }
95 : }
96 446 : name = talloc_sub_basic(mem_ctx,
97 : username + domain_len,
98 : domain,
99 : name);
100 : }
101 446 : if (sharename != NULL) {
102 350 : name = talloc_string_sub(mem_ctx, name, "%S", sharename);
103 : }
104 :
105 446 : if (name == NULL) {
106 : /* This is too security sensitive, better panic than return a
107 : * result that might be interpreted in a wrong way. */
108 0 : smb_panic("substitutions failed");
109 : }
110 :
111 446 : if ( string_to_sid( &sid, name ) ) {
112 0 : DEBUG(5,("token_contains_name: Checking for SID [%s] in token\n", name));
113 0 : return nt_token_check_sid( &sid, token );
114 : }
115 :
116 446 : if (!do_group_checks(&name, &prefix)) {
117 376 : if (!lookup_name_smbconf(mem_ctx, name, LOOKUP_NAME_ALL,
118 : NULL, NULL, &sid, &type)) {
119 0 : DEBUG(5, ("lookup_name %s failed\n", name));
120 0 : return False;
121 : }
122 376 : if (type != SID_NAME_USER) {
123 0 : DEBUG(5, ("%s is a %s, expected a user\n",
124 : name, sid_type_lookup(type)));
125 0 : return False;
126 : }
127 376 : return nt_token_check_sid(&sid, token);
128 : }
129 :
130 104 : for (/* initialized above */ ; *prefix != '\0'; prefix++) {
131 100 : if (*prefix == '+') {
132 66 : if (!lookup_name_smbconf(mem_ctx, name,
133 : LOOKUP_NAME_ALL|LOOKUP_NAME_GROUP,
134 : NULL, NULL, &sid, &type)) {
135 0 : DEBUG(5, ("lookup_name %s failed\n", name));
136 0 : return False;
137 : }
138 66 : if ((type != SID_NAME_DOM_GRP) &&
139 0 : (type != SID_NAME_ALIAS) &&
140 0 : (type != SID_NAME_WKN_GRP)) {
141 0 : DEBUG(5, ("%s is a %s, expected a group\n",
142 : name, sid_type_lookup(type)));
143 0 : return False;
144 : }
145 66 : if (nt_token_check_sid(&sid, token)) {
146 66 : return True;
147 : }
148 0 : continue;
149 : }
150 34 : if (*prefix == '&') {
151 34 : if (username) {
152 34 : if (user_in_netgroup(mem_ctx, username, name)) {
153 0 : return True;
154 : }
155 : }
156 34 : continue;
157 : }
158 0 : smb_panic("got invalid prefix from do_groups_check");
159 : }
160 4 : return False;
161 : }
162 :
163 : /*
164 : * Check whether a user is contained in the list provided.
165 : *
166 : * Please note that the user name and share names passed in here mainly for
167 : * the substitution routines that expand the parameter values, the decision
168 : * whether a user is in the list is done after a lookup_name on the expanded
169 : * parameter value, solely based on comparing the SIDs in token.
170 : *
171 : * The other use is the netgroup check when using @group or &group.
172 : */
173 :
174 48669 : bool token_contains_name_in_list(const char *username,
175 : const char *domain,
176 : const char *sharename,
177 : const struct security_token *token,
178 : const char **list)
179 : {
180 48669 : if (list == NULL) {
181 47452 : return False;
182 : }
183 597 : while (*list != NULL) {
184 446 : TALLOC_CTX *frame = talloc_stackframe();
185 0 : bool ret;
186 :
187 446 : ret = token_contains_name(frame, username, domain, sharename,
188 : token, *list);
189 446 : TALLOC_FREE(frame);
190 446 : if (ret) {
191 283 : return true;
192 : }
193 163 : list += 1;
194 : }
195 151 : return False;
196 : }
197 :
198 : /*
199 : * Check whether the user described by "token" has access to share snum.
200 : *
201 : * This looks at "invalid users" and "valid users".
202 : *
203 : * Please note that the user name and share names passed in here mainly for
204 : * the substitution routines that expand the parameter values, the decision
205 : * whether a user is in the list is done after a lookup_name on the expanded
206 : * parameter value, solely based on comparing the SIDs in token.
207 : *
208 : * The other use is the netgroup check when using @group or &group.
209 : */
210 :
211 143944 : bool user_ok_token(const char *username, const char *domain,
212 : const struct security_token *token, int snum)
213 : {
214 2299 : const struct loadparm_substitution *lp_sub =
215 143944 : loadparm_s3_global_substitution();
216 :
217 143944 : if (lp_invalid_users(snum) != NULL) {
218 64 : if (token_contains_name_in_list(username, domain,
219 32 : lp_servicename(talloc_tos(), lp_sub, snum),
220 : token,
221 : lp_invalid_users(snum))) {
222 8 : DEBUG(10, ("User %s in 'invalid users'\n", username));
223 8 : return False;
224 : }
225 : }
226 :
227 143936 : if (lp_valid_users(snum) != NULL) {
228 564 : if (!token_contains_name_in_list(username, domain,
229 282 : lp_servicename(talloc_tos(), lp_sub, snum),
230 : token,
231 : lp_valid_users(snum))) {
232 119 : DEBUG(10, ("User %s not in 'valid users'\n",
233 : username));
234 119 : return False;
235 : }
236 : }
237 :
238 143817 : DEBUG(10, ("user_ok_token: share %s is ok for unix user %s\n",
239 : lp_servicename(talloc_tos(), lp_sub, snum), username));
240 :
241 141518 : return True;
242 : }
243 :
244 : /*
245 : * Check whether the user described by "token" is restricted to read-only
246 : * access on share snum.
247 : *
248 : * This looks at "read list", "write list" and "read only".
249 : *
250 : * Please note that the user name and share names passed in here mainly for
251 : * the substitution routines that expand the parameter values, the decision
252 : * whether a user is in the list is done after a lookup_name on the expanded
253 : * parameter value, solely based on comparing the SIDs in token.
254 : *
255 : * The other use is the netgroup check when using @group or &group.
256 : */
257 :
258 96392 : bool is_share_read_only_for_token(const char *username,
259 : const char *domain,
260 : const struct security_token *token,
261 : connection_struct *conn)
262 : {
263 1542 : const struct loadparm_substitution *lp_sub =
264 96392 : loadparm_s3_global_substitution();
265 96392 : int snum = SNUM(conn);
266 96392 : bool result = conn->read_only;
267 :
268 96392 : if (lp_read_list(snum) != NULL) {
269 0 : if (token_contains_name_in_list(username, domain,
270 0 : lp_servicename(talloc_tos(), lp_sub, snum),
271 : token,
272 : lp_read_list(snum))) {
273 0 : result = True;
274 : }
275 : }
276 :
277 96392 : if (lp_write_list(snum) != NULL) {
278 48 : if (token_contains_name_in_list(username, domain,
279 24 : lp_servicename(talloc_tos(), lp_sub, snum),
280 : token,
281 : lp_write_list(snum))) {
282 24 : result = False;
283 : }
284 : }
285 :
286 96392 : DEBUG(10,("is_share_read_only_for_user: share %s is %s for unix user "
287 : "%s\n", lp_servicename(talloc_tos(), lp_sub, snum),
288 : result ? "read-only" : "read-write", username));
289 :
290 96392 : return result;
291 : }
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