1/*
2 *  Unix SMB/Netbios implementation.
3 *  SEC_DESC handling functions
4 *  Copyright (C) Jeremy R. Allison            1995-2003.
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
22/*******************************************************************
23 Create the share security tdb.
24 ********************************************************************/
25
26static struct db_context *share_db; /* used for share security descriptors */
27#define SHARE_DATABASE_VERSION_V1 1
28#define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
29
30/* Map generic permissions to file object specific permissions */
31
32extern const struct generic_mapping file_generic_mapping;
33
34static int delete_fn(struct db_record *rec, void *priv)
35{
36	rec->delete_rec(rec);
37	return 0;
38}
39
40bool share_info_db_init(void)
41{
42	const char *vstring = "INFO/version";
43	int32 vers_id;
44
45	if (share_db != NULL) {
46		return True;
47	}
48
49	share_db = db_open(NULL, state_path("share_info.tdb"), 0,
50				 TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
51	if (share_db == NULL) {
52		DEBUG(0,("Failed to open share info database %s (%s)\n",
53			state_path("share_info.tdb"), strerror(errno) ));
54		return False;
55	}
56
57	vers_id = dbwrap_fetch_int32(share_db, vstring);
58	if (vers_id == SHARE_DATABASE_VERSION_V2) {
59		return true;
60	}
61
62	if (share_db->transaction_start(share_db) != 0) {
63		DEBUG(0, ("transaction_start failed\n"));
64		TALLOC_FREE(share_db);
65		return false;
66	}
67
68	vers_id = dbwrap_fetch_int32(share_db, vstring);
69	if (vers_id == SHARE_DATABASE_VERSION_V2) {
70		/*
71		 * Race condition
72		 */
73		if (share_db->transaction_cancel(share_db)) {
74			smb_panic("transaction_cancel failed");
75		}
76		return true;
77	}
78
79	/* Cope with byte-reversed older versions of the db. */
80	if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
81		/* Written on a bigendian machine with old fetch_int code. Save as le. */
82
83		if (dbwrap_store_int32(share_db, vstring,
84				       SHARE_DATABASE_VERSION_V2) != 0) {
85			DEBUG(0, ("dbwrap_store_int32 failed\n"));
86			goto cancel;
87		}
88		vers_id = SHARE_DATABASE_VERSION_V2;
89	}
90
91	if (vers_id != SHARE_DATABASE_VERSION_V2) {
92		int ret;
93		ret = share_db->traverse(share_db, delete_fn, NULL);
94		if (ret < 0) {
95			DEBUG(0, ("traverse failed\n"));
96			goto cancel;
97		}
98		if (dbwrap_store_int32(share_db, vstring,
99				       SHARE_DATABASE_VERSION_V2) != 0) {
100			DEBUG(0, ("dbwrap_store_int32 failed\n"));
101			goto cancel;
102		}
103	}
104
105	if (share_db->transaction_commit(share_db) != 0) {
106		DEBUG(0, ("transaction_commit failed\n"));
107		return false;
108	}
109
110	return true;
111
112 cancel:
113	if (share_db->transaction_cancel(share_db)) {
114		smb_panic("transaction_cancel failed");
115	}
116
117	return false;
118}
119
120/*******************************************************************
121 Fake up a Everyone, default access as a default.
122 def_access is a GENERIC_XXX access mode.
123 ********************************************************************/
124
125SEC_DESC *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
126{
127	uint32_t sa;
128	SEC_ACE ace;
129	SEC_ACL *psa = NULL;
130	SEC_DESC *psd = NULL;
131	uint32 spec_access = def_access;
132
133	se_map_generic(&spec_access, &file_generic_mapping);
134
135	sa = (def_access | spec_access );
136	init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
137
138	if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
139		psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
140				    SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
141				    psa, psize);
142	}
143
144	if (!psd) {
145		DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
146		return NULL;
147	}
148
149	return psd;
150}
151
152/*******************************************************************
153 Pull a security descriptor from the share tdb.
154 ********************************************************************/
155
156SEC_DESC *get_share_security( TALLOC_CTX *ctx, const char *servicename,
157			      size_t *psize)
158{
159	char *key;
160	SEC_DESC *psd = NULL;
161	TDB_DATA data;
162	NTSTATUS status;
163
164	if (!share_info_db_init()) {
165		return NULL;
166	}
167
168	if (!(key = talloc_asprintf(ctx, "SECDESC/%s", servicename))) {
169		DEBUG(0, ("talloc_asprintf failed\n"));
170		return NULL;
171	}
172
173	data = dbwrap_fetch_bystring(share_db, talloc_tos(), key);
174
175	TALLOC_FREE(key);
176
177	if (data.dptr == NULL) {
178		return get_share_security_default(ctx, psize,
179						  GENERIC_ALL_ACCESS);
180	}
181
182	status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
183
184	TALLOC_FREE(data.dptr);
185
186	if (!NT_STATUS_IS_OK(status)) {
187		DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
188			  nt_errstr(status)));
189		return NULL;
190	}
191
192	if (psd)
193		*psize = ndr_size_security_descriptor(psd, NULL, 0);
194
195	return psd;
196}
197
198/*******************************************************************
199 Store a security descriptor in the share db.
200 ********************************************************************/
201
202bool set_share_security(const char *share_name, SEC_DESC *psd)
203{
204	TALLOC_CTX *frame;
205	char *key;
206	bool ret = False;
207	TDB_DATA blob;
208	NTSTATUS status;
209
210	if (!share_info_db_init()) {
211		return False;
212	}
213
214	frame = talloc_stackframe();
215
216	status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
217
218	if (!NT_STATUS_IS_OK(status)) {
219		DEBUG(0, ("marshall_sec_desc failed: %s\n",
220			  nt_errstr(status)));
221		goto out;
222	}
223
224	if (!(key = talloc_asprintf(frame, "SECDESC/%s", share_name))) {
225		DEBUG(0, ("talloc_asprintf failed\n"));
226		goto out;
227	}
228
229	status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
230				    TDB_REPLACE);
231	if (!NT_STATUS_IS_OK(status)) {
232		DEBUG(1, ("set_share_security: Failed to store secdesc for "
233			  "%s: %s\n", share_name, nt_errstr(status)));
234		goto out;
235	}
236
237	DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
238	ret = True;
239
240 out:
241	TALLOC_FREE(frame);
242	return ret;
243}
244
245/*******************************************************************
246 Delete a security descriptor.
247********************************************************************/
248
249bool delete_share_security(const char *servicename)
250{
251	TDB_DATA kbuf;
252	char *key;
253	NTSTATUS status;
254
255	if (!share_info_db_init()) {
256		return False;
257	}
258
259	if (!(key = talloc_asprintf(talloc_tos(), "SECDESC/%s",
260				    servicename))) {
261		return False;
262	}
263	kbuf = string_term_tdb_data(key);
264
265	status = dbwrap_trans_delete(share_db, kbuf);
266	if (!NT_STATUS_IS_OK(status)) {
267		DEBUG(0, ("delete_share_security: Failed to delete entry for "
268			  "share %s: %s\n", servicename, nt_errstr(status)));
269		return False;
270	}
271
272	return True;
273}
274
275/*******************************************************************
276 Can this user access with share with the required permissions ?
277********************************************************************/
278
279bool share_access_check(const NT_USER_TOKEN *token, const char *sharename,
280			uint32 desired_access)
281{
282	uint32 granted;
283	NTSTATUS status;
284	SEC_DESC *psd = NULL;
285	size_t sd_size;
286
287	psd = get_share_security(talloc_tos(), sharename, &sd_size);
288
289	if (!psd) {
290		return True;
291	}
292
293	status = se_access_check(psd, token, desired_access, &granted);
294
295	TALLOC_FREE(psd);
296
297	return NT_STATUS_IS_OK(status);
298}
299
300/***************************************************************************
301 Parse the contents of an acl string from a usershare file.
302***************************************************************************/
303
304bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, SEC_DESC **ppsd)
305{
306	size_t s_size = 0;
307	const char *pacl = acl_str;
308	int num_aces = 0;
309	SEC_ACE *ace_list = NULL;
310	SEC_ACL *psa = NULL;
311	SEC_DESC *psd = NULL;
312	size_t sd_size = 0;
313	int i;
314
315	*ppsd = NULL;
316
317	/* If the acl string is blank return "Everyone:R" */
318	if (!*acl_str) {
319		SEC_DESC *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
320		if (!default_psd) {
321			return False;
322		}
323		*ppsd = default_psd;
324		return True;
325	}
326
327	num_aces = 1;
328
329	/* Add the number of ',' characters to get the number of aces. */
330	num_aces += count_chars(pacl,',');
331
332	ace_list = TALLOC_ARRAY(ctx, SEC_ACE, num_aces);
333	if (!ace_list) {
334		return False;
335	}
336
337	for (i = 0; i < num_aces; i++) {
338		uint32_t sa;
339		uint32 g_access;
340		uint32 s_access;
341		DOM_SID sid;
342		char *sidstr;
343		enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
344
345		if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
346			DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
347				"for ':' in string '%s'\n", pacl));
348			return False;
349		}
350
351		if (!string_to_sid(&sid, sidstr)) {
352			DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
353				sidstr ));
354			return False;
355		}
356
357		switch (*pacl) {
358			case 'F': /* Full Control, ie. R+W */
359			case 'f': /* Full Control, ie. R+W */
360				s_access = g_access = GENERIC_ALL_ACCESS;
361				break;
362			case 'R': /* Read only. */
363			case 'r': /* Read only. */
364				s_access = g_access = GENERIC_READ_ACCESS;
365				break;
366			case 'D': /* Deny all to this SID. */
367			case 'd': /* Deny all to this SID. */
368				type = SEC_ACE_TYPE_ACCESS_DENIED;
369				s_access = g_access = GENERIC_ALL_ACCESS;
370				break;
371			default:
372				DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
373					pacl ));
374				return False;
375		}
376
377		pacl++;
378		if (*pacl && *pacl != ',') {
379			DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
380				pacl ));
381			return False;
382		}
383		pacl++; /* Go past any ',' */
384
385		se_map_generic(&s_access, &file_generic_mapping);
386		sa = (g_access | s_access);
387		init_sec_ace(&ace_list[i], &sid, type, sa, 0);
388	}
389
390	if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
391		psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
392				    SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
393				    psa, &sd_size);
394	}
395
396	if (!psd) {
397		DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
398		return False;
399	}
400
401	*ppsd = psd;
402	return True;
403}
404