1/*
2   Unix SMB/CIFS implementation.
3   Copyright (C) Andrew Tridgell 1992-2001
4   Copyright (C) Andrew Bartlett      2002
5   Copyright (C) Rafal Szczesniak     2002
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 3 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program.  If not, see <http://www.gnu.org/licenses/>.
19*/
20
21/* the Samba secrets database stores any generated, private information
22   such as the local SID and machine trust password */
23
24#include "includes.h"
25#include "secrets.h"
26#include "param/param.h"
27#include "system/filesys.h"
28#include "tdb_wrap.h"
29#include "lib/ldb/include/ldb.h"
30#include "../tdb/include/tdb.h"
31#include "../lib/util/util_tdb.h"
32#include "../lib/util/util_ldb.h"
33#include "librpc/gen_ndr/ndr_security.h"
34
35/**
36 * Use a TDB to store an incrementing random seed.
37 *
38 * Initialised to the current pid, the very first time Samba starts,
39 * and incremented by one each time it is needed.
40 *
41 * @note Not called by systems with a working /dev/urandom.
42 */
43static void get_rand_seed(struct tdb_wrap *secretsdb, int *new_seed)
44{
45	*new_seed = getpid();
46	if (secretsdb != NULL) {
47		tdb_change_int32_atomic(secretsdb->tdb, "INFO/random_seed", new_seed, 1);
48	}
49}
50
51/**
52 * open up the secrets database
53 */
54struct tdb_wrap *secrets_init(TALLOC_CTX *mem_ctx, struct loadparm_context *lp_ctx)
55{
56	char *fname;
57	uint8_t dummy;
58	struct tdb_wrap *tdb;
59
60	fname = private_path(mem_ctx, lp_ctx, "secrets.tdb");
61
62	tdb = tdb_wrap_open(mem_ctx, fname, 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
63
64	if (!tdb) {
65		DEBUG(0,("Failed to open %s\n", fname));
66		talloc_free(fname);
67		return NULL;
68	}
69	talloc_free(fname);
70
71	/**
72	 * Set a reseed function for the crypto random generator
73	 *
74	 * This avoids a problem where systems without /dev/urandom
75	 * could send the same challenge to multiple clients
76	 */
77	set_rand_reseed_callback((void (*) (void *, int *))get_rand_seed, tdb);
78
79	/* Ensure that the reseed is done now, while we are root, etc */
80	generate_random_buffer(&dummy, sizeof(dummy));
81
82	return tdb;
83}
84
85/**
86  connect to the secrets ldb
87*/
88struct ldb_context *secrets_db_connect(TALLOC_CTX *mem_ctx,
89					struct tevent_context *ev_ctx,
90					struct loadparm_context *lp_ctx)
91{
92	char *path;
93	const char *url;
94	struct ldb_context *ldb;
95
96	url = lp_secrets_url(lp_ctx);
97	if (!url || !url[0]) {
98		return NULL;
99	}
100
101	path = private_path(mem_ctx, lp_ctx, url);
102	if (!path) {
103		return NULL;
104	}
105
106	/* Secrets.ldb *must* always be local.  If we call for a
107	 * system_session() we will recurse */
108	ldb = ldb_init(mem_ctx, ev_ctx);
109	if (!ldb) {
110		talloc_free(path);
111		return NULL;
112	}
113
114	ldb_set_modules_dir(ldb,
115			    talloc_asprintf(ldb, "%s/ldb", lp_modulesdir(lp_ctx)));
116
117	if (ldb_connect(ldb, path, 0, NULL) != 0) {
118		talloc_free(path);
119		return NULL;
120	}
121
122	/* the update_keytab module relies on this being setup */
123	if (ldb_set_opaque(ldb, "loadparm", lp_ctx) != LDB_SUCCESS) {
124		talloc_free(path);
125		talloc_free(ldb);
126		return NULL;
127	}
128
129	talloc_free(path);
130
131	return ldb;
132}
133
134/**
135 * Retrieve the domain SID from the secrets database.
136 * @return pointer to a SID object if the SID could be obtained, NULL otherwise
137 */
138struct dom_sid *secrets_get_domain_sid(TALLOC_CTX *mem_ctx,
139				       struct tevent_context *ev_ctx,
140				       struct loadparm_context *lp_ctx,
141				       const char *domain)
142{
143	struct ldb_context *ldb;
144	struct ldb_message **msgs;
145	int ldb_ret;
146	const char *attrs[] = { "objectSid", NULL };
147	struct dom_sid *result = NULL;
148	const struct ldb_val *v;
149	enum ndr_err_code ndr_err;
150
151	ldb = secrets_db_connect(mem_ctx, ev_ctx, lp_ctx);
152	if (ldb == NULL) {
153		DEBUG(5, ("secrets_db_connect failed\n"));
154		return NULL;
155	}
156
157	ldb_ret = gendb_search(ldb, ldb,
158			       ldb_dn_new(mem_ctx, ldb, SECRETS_PRIMARY_DOMAIN_DN),
159			       &msgs, attrs,
160			       SECRETS_PRIMARY_DOMAIN_FILTER, domain);
161
162	if (ldb_ret == -1) {
163		DEBUG(5, ("Error searching for domain SID for %s: %s",
164			  domain, ldb_errstring(ldb)));
165		talloc_free(ldb);
166		return NULL;
167	}
168
169	if (ldb_ret == 0) {
170		DEBUG(5, ("Did not find domain record for %s\n", domain));
171		talloc_free(ldb);
172		return NULL;
173	}
174
175	if (ldb_ret > 1) {
176		DEBUG(5, ("Found more than one (%d) domain records for %s\n",
177			  ldb_ret, domain));
178		talloc_free(ldb);
179		return NULL;
180	}
181
182	v = ldb_msg_find_ldb_val(msgs[0], "objectSid");
183	if (v == NULL) {
184		DEBUG(0, ("Domain object for %s does not contain a SID!\n",
185			  domain));
186		return NULL;
187	}
188	result = talloc(mem_ctx, struct dom_sid);
189	if (result == NULL) {
190		talloc_free(ldb);
191		return NULL;
192	}
193
194	ndr_err = ndr_pull_struct_blob(v, result, NULL, result,
195				       (ndr_pull_flags_fn_t)ndr_pull_dom_sid);
196	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
197		talloc_free(result);
198		talloc_free(ldb);
199		return NULL;
200	}
201
202	return result;
203}
204