source: vendor/current/source3/lib/sharesec.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 14.9 KB
Line 
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#include "system/filesys.h"
22#include "../libcli/security/security.h"
23#include "../librpc/gen_ndr/ndr_security.h"
24#include "dbwrap/dbwrap.h"
25#include "dbwrap/dbwrap_open.h"
26#include "util_tdb.h"
27
28/*******************************************************************
29 Create the share security tdb.
30 ********************************************************************/
31
32static struct db_context *share_db; /* used for share security descriptors */
33#define SHARE_DATABASE_VERSION_V1 1
34#define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
35#define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
36
37#define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
38/* Map generic permissions to file object specific permissions */
39
40extern const struct generic_mapping file_generic_mapping;
41
42static int delete_fn(struct db_record *rec, void *priv)
43{
44 dbwrap_record_delete(rec);
45 return 0;
46}
47
48/*****************************************************
49 Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
50 If we find one re-write it into a canonical case form.
51*****************************************************/
52
53static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
54{
55 size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
56 const char *servicename = NULL;
57 char *c_servicename = NULL;
58 char *newkey = NULL;
59 bool *p_upgrade_ok = (bool *)priv;
60 NTSTATUS status;
61 TDB_DATA key;
62 TDB_DATA value;
63
64 key = dbwrap_record_get_key(rec);
65
66 /* Is there space for a one character sharename ? */
67 if (key.dsize <= prefix_len+2) {
68 return 0;
69 }
70
71 /* Does it start with the share key prefix ? */
72 if (memcmp(key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
73 prefix_len) != 0) {
74 return 0;
75 }
76
77 /* Is it a null terminated string as a key ? */
78 if (key.dptr[key.dsize-1] != '\0') {
79 return 0;
80 }
81
82 /* Bytes after the prefix are the sharename string. */
83 servicename = (char *)&key.dptr[prefix_len];
84 c_servicename = canonicalize_servicename(talloc_tos(), servicename);
85 if (!c_servicename) {
86 smb_panic("out of memory upgrading share security db from v2 -> v3");
87 }
88
89 if (strcmp(servicename, c_servicename) == 0) {
90 /* Old and new names match. No canonicalization needed. */
91 TALLOC_FREE(c_servicename);
92 return 0;
93 }
94
95 /* Oops. Need to canonicalize name, delete old then store new. */
96 status = dbwrap_record_delete(rec);
97 if (!NT_STATUS_IS_OK(status)) {
98 DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
99 "%s: %s\n", (const char *)key.dptr,
100 nt_errstr(status)));
101 TALLOC_FREE(c_servicename);
102 *p_upgrade_ok = false;
103 return -1;
104 } else {
105 DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
106 "%s\n", (const char *)key.dptr));
107 }
108
109 if (!(newkey = talloc_asprintf(talloc_tos(),
110 SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
111 c_servicename))) {
112 smb_panic("out of memory upgrading share security db from v2 -> v3");
113 }
114
115 value = dbwrap_record_get_value(rec);
116 status = dbwrap_store(share_db,
117 string_term_tdb_data(newkey),
118 value,
119 TDB_REPLACE);
120
121 if (!NT_STATUS_IS_OK(status)) {
122 DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
123 "%s: %s\n", c_servicename, nt_errstr(status)));
124 TALLOC_FREE(c_servicename);
125 TALLOC_FREE(newkey);
126 *p_upgrade_ok = false;
127 return -1;
128 } else {
129 DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
130 "%s\n", newkey ));
131 }
132
133 TALLOC_FREE(newkey);
134 TALLOC_FREE(c_servicename);
135
136 return 0;
137}
138
139bool share_info_db_init(void)
140{
141 const char *vstring = "INFO/version";
142 int32_t vers_id = 0;
143 bool upgrade_ok = true;
144 NTSTATUS status;
145 char *db_path;
146
147 if (share_db != NULL) {
148 return True;
149 }
150
151 db_path = state_path("share_info.tdb");
152 if (db_path == NULL) {
153 return false;
154 }
155
156 share_db = db_open(NULL, db_path, 0,
157 TDB_DEFAULT, O_RDWR|O_CREAT, 0600,
158 DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);
159 if (share_db == NULL) {
160 DEBUG(0,("Failed to open share info database %s (%s)\n",
161 db_path, strerror(errno)));
162 TALLOC_FREE(db_path);
163 return False;
164 }
165 TALLOC_FREE(db_path);
166
167 status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
168 if (!NT_STATUS_IS_OK(status)) {
169 vers_id = 0;
170 }
171
172 if (vers_id == SHARE_DATABASE_VERSION_V3) {
173 return true;
174 }
175
176 if (dbwrap_transaction_start(share_db) != 0) {
177 DEBUG(0, ("transaction_start failed\n"));
178 TALLOC_FREE(share_db);
179 return false;
180 }
181
182 status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
183 if (!NT_STATUS_IS_OK(status)) {
184 vers_id = 0;
185 }
186
187 if (vers_id == SHARE_DATABASE_VERSION_V3) {
188 /*
189 * Race condition
190 */
191 if (dbwrap_transaction_cancel(share_db)) {
192 smb_panic("transaction_cancel failed");
193 }
194 return true;
195 }
196
197 /* Move to at least V2. */
198
199 /* Cope with byte-reversed older versions of the db. */
200 if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
201 /* Written on a bigendian machine with old fetch_int code. Save as le. */
202
203 status = dbwrap_store_int32_bystring(
204 share_db, vstring, SHARE_DATABASE_VERSION_V2);
205 if (!NT_STATUS_IS_OK(status)) {
206 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
207 nt_errstr(status)));
208 goto cancel;
209 }
210 vers_id = SHARE_DATABASE_VERSION_V2;
211 }
212
213 if (vers_id != SHARE_DATABASE_VERSION_V2) {
214 status = dbwrap_traverse(share_db, delete_fn, NULL, NULL);
215 if (!NT_STATUS_IS_OK(status)) {
216 DEBUG(0, ("traverse failed\n"));
217 goto cancel;
218 }
219 status = dbwrap_store_int32_bystring(
220 share_db, vstring, SHARE_DATABASE_VERSION_V2);
221 if (!NT_STATUS_IS_OK(status)) {
222 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
223 nt_errstr(status)));
224 goto cancel;
225 }
226 }
227
228 /* Finally upgrade to version 3, with canonicalized sharenames. */
229
230 status = dbwrap_traverse(share_db, upgrade_v2_to_v3, &upgrade_ok, NULL);
231 if (!NT_STATUS_IS_OK(status) || upgrade_ok == false) {
232 DEBUG(0, ("traverse failed\n"));
233 goto cancel;
234 }
235 status = dbwrap_store_int32_bystring(
236 share_db, vstring, SHARE_DATABASE_VERSION_V3);
237 if (!NT_STATUS_IS_OK(status)) {
238 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
239 nt_errstr(status)));
240 goto cancel;
241 }
242
243 if (dbwrap_transaction_commit(share_db) != 0) {
244 DEBUG(0, ("transaction_commit failed\n"));
245 return false;
246 }
247
248 return true;
249
250 cancel:
251 if (dbwrap_transaction_cancel(share_db)) {
252 smb_panic("transaction_cancel failed");
253 }
254
255 return false;
256}
257
258/*******************************************************************
259 Fake up a Everyone, default access as a default.
260 def_access is a GENERIC_XXX access mode.
261 ********************************************************************/
262
263struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32_t def_access)
264{
265 uint32_t sa;
266 struct security_ace ace;
267 struct security_acl *psa = NULL;
268 struct security_descriptor *psd = NULL;
269 uint32_t spec_access = def_access;
270
271 se_map_generic(&spec_access, &file_generic_mapping);
272
273 sa = (def_access | spec_access );
274 init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
275
276 if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
277 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
278 SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
279 psa, psize);
280 }
281
282 if (!psd) {
283 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
284 return NULL;
285 }
286
287 return psd;
288}
289
290/*******************************************************************
291 Pull a security descriptor from the share tdb.
292 ********************************************************************/
293
294struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
295 size_t *psize)
296{
297 char *key;
298 struct security_descriptor *psd = NULL;
299 TDB_DATA data;
300 char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
301 NTSTATUS status;
302
303 if (!c_servicename) {
304 return NULL;
305 }
306
307 if (!share_info_db_init()) {
308 TALLOC_FREE(c_servicename);
309 return NULL;
310 }
311
312 if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
313 TALLOC_FREE(c_servicename);
314 DEBUG(0, ("talloc_asprintf failed\n"));
315 return NULL;
316 }
317
318 TALLOC_FREE(c_servicename);
319
320 status = dbwrap_fetch_bystring(share_db, talloc_tos(), key, &data);
321
322 TALLOC_FREE(key);
323
324 if (!NT_STATUS_IS_OK(status)) {
325 return get_share_security_default(ctx, psize,
326 SEC_RIGHTS_DIR_ALL);
327 }
328
329 status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
330
331 TALLOC_FREE(data.dptr);
332
333 if (!NT_STATUS_IS_OK(status)) {
334 return get_share_security_default(ctx, psize,
335 SEC_RIGHTS_DIR_ALL);
336 }
337
338 if (psd) {
339 *psize = ndr_size_security_descriptor(psd, 0);
340 } else {
341 return get_share_security_default(ctx, psize,
342 SEC_RIGHTS_DIR_ALL);
343 }
344
345 return psd;
346}
347
348/*******************************************************************
349 Store a security descriptor in the share db.
350 ********************************************************************/
351
352bool set_share_security(const char *share_name, struct security_descriptor *psd)
353{
354 TALLOC_CTX *frame = talloc_stackframe();
355 char *key;
356 bool ret = False;
357 TDB_DATA blob;
358 NTSTATUS status;
359 char *c_share_name = canonicalize_servicename(frame, share_name);
360
361 if (!c_share_name) {
362 goto out;
363 }
364
365 if (!share_info_db_init()) {
366 goto out;
367 }
368
369 status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
370
371 if (!NT_STATUS_IS_OK(status)) {
372 DEBUG(0, ("marshall_sec_desc failed: %s\n",
373 nt_errstr(status)));
374 goto out;
375 }
376
377 if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
378 DEBUG(0, ("talloc_asprintf failed\n"));
379 goto out;
380 }
381
382 status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
383 TDB_REPLACE);
384 if (!NT_STATUS_IS_OK(status)) {
385 DEBUG(1, ("set_share_security: Failed to store secdesc for "
386 "%s: %s\n", share_name, nt_errstr(status)));
387 goto out;
388 }
389
390 DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
391 ret = True;
392
393 out:
394 TALLOC_FREE(frame);
395 return ret;
396}
397
398/*******************************************************************
399 Delete a security descriptor.
400********************************************************************/
401
402bool delete_share_security(const char *servicename)
403{
404 TDB_DATA kbuf;
405 char *key;
406 NTSTATUS status;
407 char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
408
409 if (!c_servicename) {
410 return NULL;
411 }
412
413 if (!share_info_db_init()) {
414 TALLOC_FREE(c_servicename);
415 return False;
416 }
417
418 if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
419 c_servicename))) {
420 TALLOC_FREE(c_servicename);
421 return False;
422 }
423 kbuf = string_term_tdb_data(key);
424
425 status = dbwrap_trans_delete(share_db, kbuf);
426 if (!NT_STATUS_IS_OK(status)) {
427 DEBUG(0, ("delete_share_security: Failed to delete entry for "
428 "share %s: %s\n", c_servicename, nt_errstr(status)));
429 TALLOC_FREE(c_servicename);
430 return False;
431 }
432
433 TALLOC_FREE(c_servicename);
434 return True;
435}
436
437/*******************************************************************
438 Can this user access with share with the required permissions ?
439********************************************************************/
440
441bool share_access_check(const struct security_token *token,
442 const char *sharename,
443 uint32_t desired_access,
444 uint32_t *pgranted)
445{
446 uint32_t granted;
447 NTSTATUS status;
448 struct security_descriptor *psd = NULL;
449 size_t sd_size;
450
451 psd = get_share_security(talloc_tos(), sharename, &sd_size);
452
453 if (!psd) {
454 if (pgranted != NULL) {
455 *pgranted = desired_access;
456 }
457 return false;
458 }
459
460 status = se_file_access_check(psd, token, true, desired_access, &granted);
461
462 TALLOC_FREE(psd);
463
464 if (pgranted != NULL) {
465 *pgranted = granted;
466 }
467
468 return NT_STATUS_IS_OK(status);
469}
470
471/***************************************************************************
472 Parse the contents of an acl string from a usershare file.
473***************************************************************************/
474
475bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
476{
477 size_t s_size = 0;
478 const char *pacl = acl_str;
479 int num_aces = 0;
480 struct security_ace *ace_list = NULL;
481 struct security_acl *psa = NULL;
482 struct security_descriptor *psd = NULL;
483 size_t sd_size = 0;
484 int i;
485
486 *ppsd = NULL;
487
488 /* If the acl string is blank return "Everyone:R" */
489 if (!*acl_str) {
490 struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
491 if (!default_psd) {
492 return False;
493 }
494 *ppsd = default_psd;
495 return True;
496 }
497
498 num_aces = 1;
499
500 /* Add the number of ',' characters to get the number of aces. */
501 num_aces += count_chars(pacl,',');
502
503 ace_list = talloc_array(ctx, struct security_ace, num_aces);
504 if (!ace_list) {
505 return False;
506 }
507
508 for (i = 0; i < num_aces; i++) {
509 uint32_t sa;
510 uint32_t g_access;
511 uint32_t s_access;
512 struct dom_sid sid;
513 char *sidstr;
514 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
515
516 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
517 DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
518 "for ':' in string '%s'\n", pacl));
519 return False;
520 }
521
522 if (!string_to_sid(&sid, sidstr)) {
523 DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
524 sidstr ));
525 return False;
526 }
527
528 switch (*pacl) {
529 case 'F': /* Full Control, ie. R+W */
530 case 'f': /* Full Control, ie. R+W */
531 s_access = g_access = GENERIC_ALL_ACCESS;
532 break;
533 case 'R': /* Read only. */
534 case 'r': /* Read only. */
535 s_access = g_access = GENERIC_READ_ACCESS;
536 break;
537 case 'D': /* Deny all to this SID. */
538 case 'd': /* Deny all to this SID. */
539 type = SEC_ACE_TYPE_ACCESS_DENIED;
540 s_access = g_access = GENERIC_ALL_ACCESS;
541 break;
542 default:
543 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
544 pacl ));
545 return False;
546 }
547
548 pacl++;
549 if (*pacl && *pacl != ',') {
550 DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
551 pacl ));
552 return False;
553 }
554 pacl++; /* Go past any ',' */
555
556 se_map_generic(&s_access, &file_generic_mapping);
557 sa = (g_access | s_access);
558 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
559 }
560
561 if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
562 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
563 SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
564 psa, &sd_size);
565 }
566
567 if (!psd) {
568 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
569 return False;
570 }
571
572 *ppsd = psd;
573 return True;
574}
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