2 Unix SMB/CIFS implementation.
3 Check access to files based on security descriptors.
4 Copyright (C) Jeremy Allison 2005-2006.
5 Copyright (C) Michael Adam 2007.
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.
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.
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/>.
22 #include "../librpc/gen_ndr/ndr_security.h"
25 #define DBGC_CLASS DBGC_ACLS
28 * Security descriptor / NT Token level access check function.
30 bool can_access_file_acl(struct connection_struct
*conn
,
31 const struct smb_filename
*smb_fname
,
35 uint32_t access_granted
;
36 struct security_descriptor
*secdesc
= NULL
;
39 if (get_current_uid(conn
) == (uid_t
)0) {
40 /* I'm sorry sir, I didn't know you were root... */
44 status
= SMB_VFS_GET_NT_ACL(conn
, smb_fname
->base_name
,
49 if (!NT_STATUS_IS_OK(status
)) {
50 DEBUG(5, ("Could not get acl: %s\n", nt_errstr(status
)));
55 status
= se_access_check(secdesc
, get_current_nttok(conn
),
56 access_mask
, &access_granted
);
57 ret
= NT_STATUS_IS_OK(status
);
59 if (DEBUGLEVEL
>= 10) {
60 DEBUG(10,("can_access_file_acl for file %s "
61 "access_mask 0x%x, access_granted 0x%x "
63 smb_fname_str_dbg(smb_fname
),
64 (unsigned int)access_mask
,
65 (unsigned int)access_granted
,
66 ret
? "ALLOWED" : "DENIED" ));
67 NDR_PRINT_DEBUG(security_descriptor
, secdesc
);
74 /****************************************************************************
75 Actually emulate the in-kernel access checking for delete access. We need
76 this to successfully return ACCESS_DENIED on a file open for delete access.
77 ****************************************************************************/
79 bool can_delete_file_in_directory(connection_struct
*conn
,
80 struct smb_filename
*smb_fname
)
82 TALLOC_CTX
*ctx
= talloc_tos();
84 struct smb_filename
*smb_fname_parent
= NULL
;
88 if (!CAN_WRITE(conn
)) {
92 /* Get the parent directory permission mask and owners. */
93 if (!parent_dirname(ctx
, smb_fname
->base_name
, &dname
, NULL
)) {
97 status
= create_synthetic_smb_fname(ctx
, dname
, NULL
, NULL
,
99 if (!NT_STATUS_IS_OK(status
)) {
104 if(SMB_VFS_STAT(conn
, smb_fname_parent
) != 0) {
109 /* fast paths first */
111 if (!S_ISDIR(smb_fname_parent
->st
.st_ex_mode
)) {
115 if (get_current_uid(conn
) == (uid_t
)0) {
116 /* I'm sorry sir, I didn't know you were root... */
122 /* sticky bit means delete only by owner of file or by root or
123 * by owner of directory. */
124 if (smb_fname_parent
->st
.st_ex_mode
& S_ISVTX
) {
125 if(SMB_VFS_STAT(conn
, smb_fname
) != 0) {
126 if (errno
== ENOENT
) {
127 /* If the file doesn't already exist then
128 * yes we'll be able to delete it. */
132 DEBUG(10,("can_delete_file_in_directory: can't "
134 smb_fname_str_dbg(smb_fname
),
141 * Patch from SATOH Fumiyasu <fumiyas@miraclelinux.com>
142 * for bug #3348. Don't assume owning sticky bit
143 * directory means write access allowed.
144 * Fail to delete if we're not the owner of the file,
145 * or the owner of the directory as we have no possible
146 * chance of deleting. Otherwise, go on and check the ACL.
148 if ((get_current_uid(conn
) !=
149 smb_fname_parent
->st
.st_ex_uid
) &&
150 (get_current_uid(conn
) != smb_fname
->st
.st_ex_uid
)) {
151 DEBUG(10,("can_delete_file_in_directory: not "
152 "owner of file %s or directory %s",
153 smb_fname_str_dbg(smb_fname
),
154 smb_fname_str_dbg(smb_fname_parent
)));
161 /* now for ACL checks */
164 * There's two ways to get the permission to delete a file: First by
165 * having the DELETE bit on the file itself and second if that does
166 * not help, by the DELETE_CHILD bit on the containing directory.
168 * Here we only check the directory permissions, we will
169 * check the file DELETE permission separately.
172 ret
= can_access_file_acl(conn
, smb_fname_parent
, FILE_DELETE_CHILD
);
175 TALLOC_FREE(smb_fname_parent
);
179 /****************************************************************************
180 Actually emulate the in-kernel access checking for read/write access. We need
181 this to successfully check for ability to write for dos filetimes.
182 Note this doesn't take into account share write permissions.
183 ****************************************************************************/
185 bool can_access_file_data(connection_struct
*conn
,
186 const struct smb_filename
*smb_fname
,
189 if (!(access_mask
& (FILE_READ_DATA
|FILE_WRITE_DATA
))) {
192 access_mask
&= (FILE_READ_DATA
|FILE_WRITE_DATA
);
194 /* some fast paths first */
196 DEBUG(10,("can_access_file_data: requesting 0x%x on file %s\n",
197 (unsigned int)access_mask
, smb_fname_str_dbg(smb_fname
)));
199 if (get_current_uid(conn
) == (uid_t
)0) {
200 /* I'm sorry sir, I didn't know you were root... */
204 SMB_ASSERT(VALID_STAT(smb_fname
->st
));
206 /* Check primary owner access. */
207 if (get_current_uid(conn
) == smb_fname
->st
.st_ex_uid
) {
208 switch (access_mask
) {
210 return (smb_fname
->st
.st_ex_mode
& S_IRUSR
) ?
213 case FILE_WRITE_DATA
:
214 return (smb_fname
->st
.st_ex_mode
& S_IWUSR
) ?
217 default: /* FILE_READ_DATA|FILE_WRITE_DATA */
219 if ((smb_fname
->st
.st_ex_mode
&
220 (S_IWUSR
|S_IRUSR
)) ==
229 /* now for ACL checks */
231 return can_access_file_acl(conn
, smb_fname
, access_mask
);
234 /****************************************************************************
235 Userspace check for write access.
236 Note this doesn't take into account share write permissions.
237 ****************************************************************************/
239 bool can_write_to_file(connection_struct
*conn
,
240 const struct smb_filename
*smb_fname
)
242 return can_access_file_data(conn
, smb_fname
, FILE_WRITE_DATA
);
245 /****************************************************************************
246 Check for an existing default Windows ACL on a directory.
247 ****************************************************************************/
249 bool directory_has_default_acl(connection_struct
*conn
, const char *fname
)
251 /* returns talloced off tos. */
252 struct security_descriptor
*secdesc
= NULL
;
254 NTSTATUS status
= SMB_VFS_GET_NT_ACL(conn
, fname
,
255 SECINFO_DACL
, &secdesc
);
257 if (!NT_STATUS_IS_OK(status
) || secdesc
== NULL
) {
261 for (i
= 0; i
< secdesc
->dacl
->num_aces
; i
++) {
262 struct security_ace
*psa
= &secdesc
->dacl
->aces
[i
];
263 if (psa
->flags
& (SEC_ACE_FLAG_OBJECT_INHERIT
|
264 SEC_ACE_FLAG_CONTAINER_INHERIT
)) {
265 TALLOC_FREE(secdesc
);
269 TALLOC_FREE(secdesc
);