bc3edd7d049dfe375d91d3ea8f5c4cc6efc4ec46
[jra/samba/.git] / source3 / modules / vfs_acl_xattr.c
1 /*
2  * Store Windows ACLs in xattrs.
3  *
4  * Copyright (C) Volker Lendecke, 2008
5  * Copyright (C) Jeremy Allison, 2008
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 /* NOTE: This is an experimental module, not yet finished. JRA. */
22
23 #include "includes.h"
24 #include "librpc/gen_ndr/xattr.h"
25 #include "librpc/gen_ndr/ndr_xattr.h"
26
27 #undef DBGC_CLASS
28 #define DBGC_CLASS DBGC_VFS
29
30 /*******************************************************************
31  Parse out a struct security_descriptor from a DATA_BLOB.
32 *******************************************************************/
33
34 static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
35                                 uint32 security_info,
36                                 struct security_descriptor **ppdesc)
37 {
38         TALLOC_CTX *ctx = talloc_tos();
39         struct xattr_NTACL xacl;
40         enum ndr_err_code ndr_err;
41         size_t sd_size;
42
43         ndr_err = ndr_pull_struct_blob(pblob, ctx, NULL, &xacl,
44                         (ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);
45
46         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
47                 DEBUG(5, ("parse_acl_blob: ndr_pull_xattr_NTACL failed: %s\n",
48                         ndr_errstr(ndr_err)));
49                 return ndr_map_error2ntstatus(ndr_err);;
50         }
51
52         if (xacl.version != 2) {
53                 return NT_STATUS_REVISION_MISMATCH;
54         }
55
56         *ppdesc = make_sec_desc(ctx, SEC_DESC_REVISION, xacl.info.sd_hs->sd->type | SEC_DESC_SELF_RELATIVE,
57                         (security_info & OWNER_SECURITY_INFORMATION)
58                         ? xacl.info.sd_hs->sd->owner_sid : NULL,
59                         (security_info & GROUP_SECURITY_INFORMATION)
60                         ? xacl.info.sd_hs->sd->group_sid : NULL,
61                         (security_info & SACL_SECURITY_INFORMATION)
62                         ? xacl.info.sd_hs->sd->sacl : NULL,
63                         (security_info & DACL_SECURITY_INFORMATION)
64                         ? xacl.info.sd_hs->sd->dacl : NULL,
65                         &sd_size);
66
67         TALLOC_FREE(xacl.info.sd);
68
69         return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
70 }
71
72 /*******************************************************************
73  Pull a security descriptor into a DATA_BLOB from a xattr.
74 *******************************************************************/
75
76 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
77                         vfs_handle_struct *handle,
78                         files_struct *fsp,
79                         const char *name,
80                         DATA_BLOB *pblob)
81 {
82         size_t size = 1024;
83         uint8_t *val = NULL;
84         uint8_t *tmp;
85         ssize_t sizeret;
86         int saved_errno = 0;
87
88         ZERO_STRUCTP(pblob);
89
90   again:
91
92         tmp = TALLOC_REALLOC_ARRAY(ctx, val, uint8_t, size);
93         if (tmp == NULL) {
94                 TALLOC_FREE(val);
95                 return NT_STATUS_NO_MEMORY;
96         }
97         val = tmp;
98
99         become_root();
100         if (fsp && fsp->fh->fd != -1) {
101                 sizeret = SMB_VFS_FGETXATTR(fsp, XATTR_NTACL_NAME, val, size);
102         } else {
103                 sizeret = SMB_VFS_GETXATTR(handle->conn, name,
104                                         XATTR_NTACL_NAME, val, size);
105         }
106         if (sizeret == -1) {
107                 saved_errno = errno;
108         }
109         unbecome_root();
110
111         /* Max ACL size is 65536 bytes. */
112         if (sizeret == -1) {
113                 errno = saved_errno;
114                 if ((errno == ERANGE) && (size != 65536)) {
115                         /* Too small, try again. */
116                         size = 65536;
117                         goto again;
118                 }
119
120                 /* Real error - exit here. */
121                 TALLOC_FREE(val);
122                 return map_nt_error_from_unix(errno);
123         }
124
125         pblob->data = val;
126         pblob->length = sizeret;
127         return NT_STATUS_OK;
128 }
129
130 /*******************************************************************
131  Create a DATA_BLOB from a security descriptor.
132 *******************************************************************/
133
134 static NTSTATUS create_acl_blob(const struct security_descriptor *psd, DATA_BLOB *pblob)
135 {
136         struct xattr_NTACL xacl;
137         struct security_descriptor_hash sd_hs;
138         enum ndr_err_code ndr_err;
139         TALLOC_CTX *ctx = talloc_tos();
140
141         ZERO_STRUCT(xacl);
142         ZERO_STRUCT(sd_hs);
143
144         xacl.version = 2;
145         xacl.info.sd_hs = &sd_hs;
146         xacl.info.sd_hs->sd = CONST_DISCARD(struct security_descriptor *, psd);
147         memset(&xacl.info.sd_hs->hash[0], '\0', 16);
148
149         ndr_err = ndr_push_struct_blob(
150                         pblob, ctx, NULL, &xacl,
151                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
152
153         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
154                 DEBUG(5, ("create_acl_blob: ndr_push_xattr_NTACL failed: %s\n",
155                         ndr_errstr(ndr_err)));
156                 return ndr_map_error2ntstatus(ndr_err);;
157         }
158
159         return NT_STATUS_OK;
160 }
161
162 /*******************************************************************
163  Store a DATA_BLOB into an xattr given an fsp pointer.
164 *******************************************************************/
165
166 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
167                                 files_struct *fsp,
168                                 DATA_BLOB *pblob)
169 {
170         int ret;
171         int saved_errno = 0;
172
173         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
174                         (unsigned int)pblob->length, fsp->fsp_name));
175
176         become_root();
177         if (fsp->fh->fd != -1) {
178                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
179                         pblob->data, pblob->length, 0);
180         } else {
181                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
182                                 XATTR_NTACL_NAME,
183                                 pblob->data, pblob->length, 0);
184         }
185         if (ret) {
186                 saved_errno = errno;
187         }
188         unbecome_root();
189         if (ret) {
190                 errno = saved_errno;
191                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
192                         "with error %s\n",
193                         fsp->fsp_name,
194                         strerror(errno) ));
195                 return map_nt_error_from_unix(errno);
196         }
197         return NT_STATUS_OK;
198 }
199
200 /*******************************************************************
201  Store a DATA_BLOB into an xattr given a pathname.
202 *******************************************************************/
203
204 static NTSTATUS store_acl_blob_pathname(vfs_handle_struct *handle,
205                                         const char *fname,
206                                         DATA_BLOB *pblob)
207 {
208         connection_struct *conn = handle->conn;
209         int ret;
210         int saved_errno = 0;
211
212         DEBUG(10,("store_acl_blob_pathname: storing blob "
213                         "length %u on file %s\n",
214                         (unsigned int)pblob->length, fname));
215
216         become_root();
217         ret = SMB_VFS_SETXATTR(conn, fname,
218                                 XATTR_NTACL_NAME,
219                                 pblob->data, pblob->length, 0);
220         if (ret) {
221                 saved_errno = errno;
222         }
223         unbecome_root();
224         if (ret) {
225                 errno = saved_errno;
226                 DEBUG(5, ("store_acl_blob_pathname: setting attr failed "
227                         "for file %s with error %s\n",
228                         fname,
229                         strerror(errno) ));
230                 return map_nt_error_from_unix(errno);
231         }
232         return NT_STATUS_OK;
233 }
234
235 /*******************************************************************
236  Store a DATA_BLOB into an xattr given a pathname.
237 *******************************************************************/
238
239 static NTSTATUS get_nt_acl_xattr_internal(vfs_handle_struct *handle,
240                                         files_struct *fsp,
241                                         const char *name,
242                                         uint32 security_info,
243                                         struct security_descriptor **ppdesc)
244 {
245         TALLOC_CTX *ctx = talloc_tos();
246         DATA_BLOB blob;
247         NTSTATUS status;
248
249         if (fsp && name == NULL) {
250                 name = fsp->fsp_name;
251         }
252
253         DEBUG(10, ("get_nt_acl_xattr_internal: name=%s\n", name));
254
255         status = get_acl_blob(ctx, handle, fsp, name, &blob);
256         if (!NT_STATUS_IS_OK(status)) {
257                 DEBUG(10, ("get_acl_blob returned %s\n", nt_errstr(status)));
258                 return status;
259         }
260
261         status = parse_acl_blob(&blob, security_info, ppdesc);
262         if (!NT_STATUS_IS_OK(status)) {
263                 DEBUG(10, ("parse_acl_blob returned %s\n",
264                                 nt_errstr(status)));
265                 return status;
266         }
267
268         TALLOC_FREE(blob.data);
269         return status;
270 }
271
272 /*********************************************************************
273  Create a default security descriptor for a file in case no inheritance
274  exists. All permissions to the owner and SYSTEM.
275 *********************************************************************/
276
277 static struct security_descriptor *default_file_sd(TALLOC_CTX *mem_ctx,
278                                                 SMB_STRUCT_STAT *psbuf)
279 {
280         struct dom_sid owner_sid, group_sid;
281         size_t sd_size;
282         struct security_ace *pace = NULL;
283         struct security_acl *pacl = NULL;
284
285         uid_to_sid(&owner_sid, psbuf->st_uid);
286         gid_to_sid(&group_sid, psbuf->st_gid);
287
288         pace = TALLOC_ARRAY(mem_ctx, struct security_ace, 2);
289         if (!pace) {
290                 return NULL;
291         }
292
293         init_sec_ace(&pace[0], &owner_sid, SEC_ACE_TYPE_ACCESS_ALLOWED,
294                         SEC_RIGHTS_FILE_ALL, 0);
295         init_sec_ace(&pace[1], &global_sid_System, SEC_ACE_TYPE_ACCESS_ALLOWED,
296                         SEC_RIGHTS_FILE_ALL, 0);
297
298         pacl = make_sec_acl(mem_ctx,
299                                 NT4_ACL_REVISION,
300                                 2,
301                                 pace);
302         if (!pacl) {
303                 return NULL;
304         }
305         return make_sec_desc(mem_ctx,
306                         SECURITY_DESCRIPTOR_REVISION_1,
307                         SEC_DESC_SELF_RELATIVE|SEC_DESC_DACL_PRESENT,
308                         &owner_sid,
309                         &group_sid,
310                         NULL,
311                         pacl,
312                         &sd_size);
313 }
314
315 /*********************************************************************
316 *********************************************************************/
317
318 static NTSTATUS inherit_new_acl(vfs_handle_struct *handle,
319                                         const char *fname,
320                                         files_struct *fsp,
321                                         bool container)
322 {
323         TALLOC_CTX *ctx = talloc_tos();
324         NTSTATUS status;
325         struct security_descriptor *parent_desc = NULL;
326         struct security_descriptor *psd = NULL;
327         DATA_BLOB blob;
328         size_t size;
329         char *parent_name;
330
331         if (!parent_dirname_talloc(ctx,
332                                 fname,
333                                 &parent_name,
334                                 NULL)) {
335                 return NT_STATUS_NO_MEMORY;
336         }
337
338         DEBUG(10,("inherit_new_acl: check directory %s\n",
339                         parent_name));
340
341         status = get_nt_acl_xattr_internal(handle,
342                                         NULL,
343                                         parent_name,
344                                         (OWNER_SECURITY_INFORMATION |
345                                          GROUP_SECURITY_INFORMATION |
346                                          DACL_SECURITY_INFORMATION),
347                                         &parent_desc);
348         if (NT_STATUS_IS_OK(status)) {
349                 /* Create an inherited descriptor from the parent. */
350
351                 if (DEBUGLEVEL >= 10) {
352                         DEBUG(10,("inherit_new_acl: parent acl is:\n"));
353                         NDR_PRINT_DEBUG(security_descriptor, parent_desc);
354                 }
355
356                 status = se_create_child_secdesc(ctx,
357                                 &psd,
358                                 &size,
359                                 parent_desc,
360                                 &handle->conn->server_info->ptok->user_sids[PRIMARY_USER_SID_INDEX],
361                                 &handle->conn->server_info->ptok->user_sids[PRIMARY_GROUP_SID_INDEX],
362                                 container);
363                 if (!NT_STATUS_IS_OK(status)) {
364                         return status;
365                 }
366
367                 if (DEBUGLEVEL >= 10) {
368                         DEBUG(10,("inherit_new_acl: child acl is:\n"));
369                         NDR_PRINT_DEBUG(security_descriptor, psd);
370                 }
371
372         } else {
373                 DEBUG(10,("inherit_new_acl: directory %s failed "
374                         "to get acl %s\n",
375                         parent_name,
376                         nt_errstr(status) ));
377         }
378
379         if (!psd || psd->dacl == NULL) {
380                 SMB_STRUCT_STAT sbuf;
381                 int ret;
382
383                 TALLOC_FREE(psd);
384                 if (fsp && !fsp->is_directory && fsp->fh->fd != -1) {
385                         ret = SMB_VFS_FSTAT(fsp, &sbuf);
386                 } else {
387                         ret = SMB_VFS_STAT(handle->conn,fname, &sbuf);
388                 }
389                 if (ret == -1) {
390                         return map_nt_error_from_unix(errno);
391                 }
392                 psd = default_file_sd(ctx, &sbuf);
393                 if (!psd) {
394                         return NT_STATUS_NO_MEMORY;
395                 }
396
397                 if (DEBUGLEVEL >= 10) {
398                         DEBUG(10,("inherit_new_acl: default acl is:\n"));
399                         NDR_PRINT_DEBUG(security_descriptor, psd);
400                 }
401         }
402
403         status = create_acl_blob(psd, &blob);
404         if (!NT_STATUS_IS_OK(status)) {
405                 return status;
406         }
407         if (fsp) {
408                 return store_acl_blob_fsp(handle, fsp, &blob);
409         } else {
410                 return store_acl_blob_pathname(handle, fname, &blob);
411         }
412 }
413
414 /*********************************************************************
415  Check ACL on open. For new files inherit from parent directory.
416 *********************************************************************/
417
418 static int open_acl_xattr(vfs_handle_struct *handle,
419                                         const char *fname,
420                                         files_struct *fsp,
421                                         int flags,
422                                         mode_t mode)
423 {
424         uint32_t access_granted = 0;
425         struct security_descriptor *pdesc = NULL;
426         bool file_existed = true;
427         NTSTATUS status = get_nt_acl_xattr_internal(handle,
428                                         NULL,
429                                         fname,
430                                         (OWNER_SECURITY_INFORMATION |
431                                          GROUP_SECURITY_INFORMATION |
432                                          DACL_SECURITY_INFORMATION),
433                                         &pdesc);
434         if (NT_STATUS_IS_OK(status)) {
435                 /* See if we can access it. */
436                 status = smb1_file_se_access_check(pdesc,
437                                         handle->conn->server_info->ptok,
438                                         fsp->access_mask,
439                                         &access_granted);
440                 if (!NT_STATUS_IS_OK(status)) {
441                         DEBUG(10,("open_acl_xattr: file %s open "
442                                 "refused with error %s\n",
443                                 fname,
444                                 nt_errstr(status) ));
445                         errno = map_errno_from_nt_status(status);
446                         return -1;
447                 }
448         } else if (NT_STATUS_EQUAL(status,NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
449                 file_existed = false;
450         }
451
452         DEBUG(10,("open_acl_xattr: get_nt_acl_attr_internal for "
453                 "file %s returned %s\n",
454                 fname,
455                 nt_errstr(status) ));
456
457         fsp->fh->fd = SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
458
459         if (!file_existed && fsp->fh->fd != -1) {
460                 /* File was created. Inherit from parent directory. */
461                 string_set(&fsp->fsp_name, fname);
462                 inherit_new_acl(handle, fname, fsp, false);
463         }
464
465         return fsp->fh->fd;
466 }
467
468 static int mkdir_acl_xattr(vfs_handle_struct *handle, const char *path, mode_t mode)
469 {
470         int ret = SMB_VFS_NEXT_MKDIR(handle, path, mode);
471
472         if (ret == -1) {
473                 return ret;
474         }
475         /* New directory - inherit from parent. */
476         inherit_new_acl(handle, path, NULL, true);
477         return ret;
478 }
479
480 /*********************************************************************
481  Fetch a security descriptor given an fsp.
482 *********************************************************************/
483
484 static NTSTATUS fget_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
485         uint32 security_info, struct security_descriptor **ppdesc)
486 {
487         NTSTATUS status = get_nt_acl_xattr_internal(handle, fsp,
488                                 NULL, security_info, ppdesc);
489         if (NT_STATUS_IS_OK(status)) {
490                 if (DEBUGLEVEL >= 10) {
491                         DEBUG(10,("fget_nt_acl_xattr: returning xattr sd for file %s\n",
492                                 fsp->fsp_name));
493                         NDR_PRINT_DEBUG(security_descriptor, *ppdesc);
494                 }
495                 return NT_STATUS_OK;
496         }
497
498         DEBUG(10,("fget_nt_acl_xattr: failed to get xattr sd for file %s, Error %s\n",
499                         fsp->fsp_name,
500                         nt_errstr(status) ));
501
502         return SMB_VFS_NEXT_FGET_NT_ACL(handle, fsp,
503                         security_info, ppdesc);
504 }
505
506 /*********************************************************************
507  Fetch a security descriptor given a pathname.
508 *********************************************************************/
509
510 static NTSTATUS get_nt_acl_xattr(vfs_handle_struct *handle,
511         const char *name, uint32 security_info, struct security_descriptor **ppdesc)
512 {
513         NTSTATUS status = get_nt_acl_xattr_internal(handle, NULL,
514                                 name, security_info, ppdesc);
515         if (NT_STATUS_IS_OK(status)) {
516                 if (DEBUGLEVEL >= 10) {
517                         DEBUG(10,("get_nt_acl_xattr: returning xattr sd for file %s\n",
518                                 name));
519                         NDR_PRINT_DEBUG(security_descriptor, *ppdesc);
520                 }
521                 return NT_STATUS_OK;
522         }
523
524         DEBUG(10,("get_nt_acl_xattr: failed to get xattr sd for file %s, Error %s\n",
525                         name,
526                         nt_errstr(status) ));
527
528         return SMB_VFS_NEXT_GET_NT_ACL(handle, name,
529                         security_info, ppdesc);
530 }
531
532 /*********************************************************************
533  Store a security descriptor given an fsp.
534 *********************************************************************/
535
536 static NTSTATUS fset_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
537         uint32 security_info_sent, const struct security_descriptor *psd)
538 {
539         NTSTATUS status;
540         DATA_BLOB blob;
541
542         if (DEBUGLEVEL >= 10) {
543                 DEBUG(10,("fset_nt_acl_xattr: incoming sd for file %s\n",
544                         fsp->fsp_name));
545                 NDR_PRINT_DEBUG(security_descriptor,
546                         CONST_DISCARD(struct security_descriptor *,psd));
547         }
548
549         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
550         if (!NT_STATUS_IS_OK(status)) {
551                 return status;
552         }
553
554         /* Ensure owner and group are set. */
555         if (!psd->owner_sid || !psd->group_sid) {
556                 int ret;
557                 SMB_STRUCT_STAT sbuf;
558                 DOM_SID owner_sid, group_sid;
559                 struct security_descriptor *nc_psd = dup_sec_desc(talloc_tos(), psd);
560
561                 if (!nc_psd) {
562                         return NT_STATUS_OK;
563                 }
564                 if (fsp->is_directory || fsp->fh->fd == -1) {
565                         ret = SMB_VFS_STAT(fsp->conn,fsp->fsp_name, &sbuf);
566                 } else {
567                         ret = SMB_VFS_FSTAT(fsp, &sbuf);
568                 }
569                 if (ret == -1) {
570                         /* Lower level acl set succeeded,
571                          * so still return OK. */
572                         return NT_STATUS_OK;
573                 }
574                 create_file_sids(&sbuf, &owner_sid, &group_sid);
575                 /* This is safe as nc_psd is discarded at fn exit. */
576                 nc_psd->owner_sid = &owner_sid;
577                 nc_psd->group_sid = &group_sid;
578                 security_info_sent |= (OWNER_SECURITY_INFORMATION|GROUP_SECURITY_INFORMATION);
579                 psd = nc_psd;
580         }
581
582         if ((security_info_sent & DACL_SECURITY_INFORMATION) &&
583                         psd->dacl != NULL &&
584                         (psd->type & (SE_DESC_DACL_AUTO_INHERITED|
585                                 SE_DESC_DACL_AUTO_INHERIT_REQ))==
586                                 (SE_DESC_DACL_AUTO_INHERITED|
587                                 SE_DESC_DACL_AUTO_INHERIT_REQ) ) {
588                 struct security_descriptor *new_psd = NULL;
589                 status = append_parent_acl(fsp, psd, &new_psd);
590                 if (!NT_STATUS_IS_OK(status)) {
591                         /* Lower level acl set succeeded,
592                          * so still return OK. */
593                         return NT_STATUS_OK;
594                 }
595                 psd = new_psd;
596         }
597
598         if (DEBUGLEVEL >= 10) {
599                 DEBUG(10,("fset_nt_acl_xattr: storing xattr sd for file %s\n",
600                         fsp->fsp_name));
601                 NDR_PRINT_DEBUG(security_descriptor,
602                         CONST_DISCARD(struct security_descriptor *,psd));
603         }
604         create_acl_blob(psd, &blob);
605         store_acl_blob_fsp(handle, fsp, &blob);
606
607         return NT_STATUS_OK;
608 }
609
610 /* VFS operations structure */
611
612 static vfs_op_tuple skel_op_tuples[] =
613 {
614         {SMB_VFS_OP(mkdir_acl_xattr), SMB_VFS_OP_MKDIR, SMB_VFS_LAYER_TRANSPARENT},
615         {SMB_VFS_OP(open_acl_xattr),  SMB_VFS_OP_OPEN,  SMB_VFS_LAYER_TRANSPARENT},
616
617         /* NT File ACL operations */
618
619         {SMB_VFS_OP(fget_nt_acl_xattr),SMB_VFS_OP_FGET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
620         {SMB_VFS_OP(get_nt_acl_xattr), SMB_VFS_OP_GET_NT_ACL, SMB_VFS_LAYER_TRANSPARENT},
621         {SMB_VFS_OP(fset_nt_acl_xattr),SMB_VFS_OP_FSET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
622
623         {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
624 };
625
626 NTSTATUS vfs_acl_xattr_init(void)
627 {
628         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr", skel_op_tuples);
629 }