summaryrefslogtreecommitdiff
path: root/source4/dsdb/samdb/ldb_modules/kludge_acl.c
blob: 0d0a266119f527dd09293202202d1daa5814e1f6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
/* 
   ldb database library

   Copyright (C) Andrew Bartlett 2005

    This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
 *  Name: ldb
 *
 *  Component: ldb kludge ACL module
 *
 *  Description: Simple module to enforce a simple form of access
 *               control, sufficient for securing a default Samba4 
 *               installation.
 *
 *  Author: Andrew Bartlett
 */

#include "includes.h"
#include "ldb/include/ldb.h"
#include "ldb/include/ldb_errors.h"
#include "ldb/include/ldb_private.h"
#include "auth/auth.h"

/* Kludge ACL rules:
 *
 * - System can read passwords
 * - Administrators can write anything
 * - Users can read anything that is not a password
 *
 */

enum user_is {
	ANONYMOUS,
	USER,
	ADMINISTRATOR,
	SYSTEM
};

struct kludge_private_data {
	const char **password_attrs;
};

static enum user_is what_is_user(struct ldb_module *module) 
{
	struct auth_session_info *session_info
		= ldb_get_opaque(module->ldb, "sessionInfo");
	if (!session_info) {
		return ANONYMOUS;
	}
	
	if (is_system_token(session_info->security_token)) {
		return SYSTEM;
	}

	if (is_administrator_token(session_info->security_token)) {
		return ADMINISTRATOR;
	}
	if (is_authenticated_token(session_info->security_token)) {
		return USER;
	}
	if (is_anonymous_token(session_info->security_token)) {
		return ANONYMOUS;
	}
	return ANONYMOUS;
}

static const char *user_name(TALLOC_CTX *mem_ctx, struct ldb_module *module) 
{
	struct auth_session_info *session_info
		= ldb_get_opaque(module->ldb, "sessionInfo");
	if (!session_info) {
		return "UNKNOWN (NULL)";
	}
	
	return talloc_asprintf(mem_ctx, "%s\\%s",
			       session_info->server_info->domain_name,
			       session_info->server_info->account_name);
	return ANONYMOUS;
}

/* search */
static int kludge_acl_search(struct ldb_module *module, struct ldb_request *req)
{
	struct kludge_private_data *data = talloc_get_type(module->private_data, struct kludge_private_data);
	struct ldb_message *msg;
	enum user_is user_type;
	int i, j, ret;

	/* go down the path and wait for reply to filter out stuff if needed */
	ret = ldb_next_request(module, req);

	/* We may not be fully initialised yet, or we might have just
	 * got an error */
	if (ret != LDB_SUCCESS || !data->password_attrs) {
		return ret;
	}

	user_type = what_is_user(module);
	switch (user_type) {
	case SYSTEM:
	case ADMINISTRATOR:
		return ret;
	default:
		/* For every message, remove password attributes */
		for (i=0; i < req->op.search.res->count; i++) {
			msg = req->op.search.res->msgs[i];
			for (j=0; data->password_attrs[j]; j++) {
				ldb_msg_remove_attr(msg, data->password_attrs[j]);
			}
		}
	}
	return ret;
}

/* ANY change type */
static int kludge_acl_change(struct ldb_module *module, struct ldb_request *req){
	enum user_is user_type = what_is_user(module);
	switch (user_type) {
	case SYSTEM:
	case ADMINISTRATOR:
		return ldb_next_request(module, req);
	default:
		ldb_set_errstring(module, 
				  talloc_asprintf(req, "kludge_acl_change: "
						  "attempted database modify not permitted. User %s is not SYSTEM or an administrator",
						  user_name(req, module)));
		return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
	}
}

/* start a transaction */
static int kludge_acl_start_trans(struct ldb_module *module)
{
	return ldb_next_start_trans(module);
}

/* end a transaction */
static int kludge_acl_end_trans(struct ldb_module *module)
{
	return ldb_next_end_trans(module);
}

/* delete a transaction */
static int kludge_acl_del_trans(struct ldb_module *module)
{
	return ldb_next_del_trans(module);
}

static int kludge_acl_request(struct ldb_module *module, struct ldb_request *req)
{
	switch (req->operation) {

	case LDB_REQ_SEARCH:
		return kludge_acl_search(module, req);
	case LDB_REQ_REGISTER:
		return ldb_next_request(module, req);
	default:
		/* anything else must be a change of some kind */
		return kludge_acl_change(module, req);
	}
}

static int kludge_acl_init_2(struct ldb_module *module)
{
	int ret, i;
	TALLOC_CTX *mem_ctx = talloc_new(module);
	const char *attrs[] = { "attribute", NULL };
	struct ldb_result *res;
	struct ldb_message *msg;
	struct ldb_message_element *password_attributes;

	struct kludge_private_data *data = talloc_get_type(module->private_data, struct kludge_private_data);
	data->password_attrs = NULL;

	if (!mem_ctx) {
		return LDB_ERR_OPERATIONS_ERROR;
	}

	ret = ldb_search(module->ldb, ldb_dn_explode(mem_ctx, "@KLUDGEACL"),
			 LDB_SCOPE_BASE,
			 NULL, attrs,
			 &res);
	if (ret != LDB_SUCCESS) {
		talloc_free(mem_ctx);
		return ret;
	}
	talloc_steal(mem_ctx, res);
	if (res->count == 0) {
		talloc_free(mem_ctx);
		data->password_attrs = NULL;
		return LDB_SUCCESS;
	}

	if (res->count > 1) {
		talloc_free(mem_ctx);
		return LDB_ERR_CONSTRAINT_VIOLATION;
	}

	msg = res->msgs[0];

	password_attributes = ldb_msg_find_element(msg, "passwordAttribute");
	if (!password_attributes) {
		talloc_free(mem_ctx);
		return LDB_SUCCESS;
	}
	data->password_attrs = talloc_array(data, const char *, password_attributes->num_values + 1);
	if (!data->password_attrs) {
		talloc_free(mem_ctx);
		return LDB_ERR_OPERATIONS_ERROR;
	}
	for (i=0; i < password_attributes->num_values; i++) {
		data->password_attrs[i] = (const char *)password_attributes->values[i].data;	
		talloc_steal(data->password_attrs, password_attributes->values[i].data);
	}
	data->password_attrs[i] = NULL;
	talloc_free(mem_ctx);
	return LDB_SUCCESS;
}

static const struct ldb_module_ops kludge_acl_ops = {
	.name		   = "kludge_acl",
	.request      	   = kludge_acl_request,
	.start_transaction = kludge_acl_start_trans,
	.end_transaction   = kludge_acl_end_trans,
	.del_transaction   = kludge_acl_del_trans,
	.second_stage_init = kludge_acl_init_2
};

struct ldb_module *kludge_acl_module_init(struct ldb_context *ldb, const char *options[])
{
	struct ldb_module *ctx;
	struct kludge_private_data *data;

	ctx = talloc(ldb, struct ldb_module);
	if (!ctx)
		return NULL;

	data = talloc(ctx, struct kludge_private_data);
	if (data == NULL) {
		talloc_free(ctx);
		return NULL;
	}

	data->password_attrs = NULL;
	ctx->private_data = data;

	ctx->ldb = ldb;
	ctx->prev = ctx->next = NULL;
	ctx->ops = &kludge_acl_ops;

	return ctx;
}