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 "system/filesys.h"
23 #include "../libcli/security/security.h"
24 #include "../librpc/gen_ndr/ndr_security.h"
25 #include "smbd/smbd.h"
28 #define DBGC_CLASS DBGC_ACLS
31 * Security descriptor / NT Token level access check function.
33 bool can_access_file_acl(struct connection_struct *conn,
34 const struct smb_filename *smb_fname,
38 uint32_t access_granted;
39 struct security_descriptor *secdesc = NULL;
42 if (get_current_uid(conn) == (uid_t)0) {
43 /* I'm sorry sir, I didn't know you were root... */
47 status = SMB_VFS_GET_NT_ACL(conn, smb_fname->base_name,
52 if (!NT_STATUS_IS_OK(status)) {
53 DEBUG(5, ("Could not get acl: %s\n", nt_errstr(status)));
58 status = se_access_check(secdesc, get_current_nttok(conn),
59 access_mask, &access_granted);
60 ret = NT_STATUS_IS_OK(status);
62 if (DEBUGLEVEL >= 10) {
63 DEBUG(10,("can_access_file_acl for file %s "
64 "access_mask 0x%x, access_granted 0x%x "
66 smb_fname_str_dbg(smb_fname),
67 (unsigned int)access_mask,
68 (unsigned int)access_granted,
69 ret ? "ALLOWED" : "DENIED" ));
70 NDR_PRINT_DEBUG(security_descriptor, secdesc);
77 /****************************************************************************
78 Actually emulate the in-kernel access checking for delete access. We need
79 this to successfully return ACCESS_DENIED on a file open for delete access.
80 ****************************************************************************/
82 bool can_delete_file_in_directory(connection_struct *conn,
83 struct smb_filename *smb_fname)
85 TALLOC_CTX *ctx = talloc_tos();
87 struct smb_filename *smb_fname_parent = NULL;
91 if (!CAN_WRITE(conn)) {
95 /* Get the parent directory permission mask and owners. */
96 if (!parent_dirname(ctx, smb_fname->base_name, &dname, NULL)) {
100 status = create_synthetic_smb_fname(ctx, dname, NULL, NULL,
102 if (!NT_STATUS_IS_OK(status)) {
107 if(SMB_VFS_STAT(conn, smb_fname_parent) != 0) {
112 /* fast paths first */
114 if (!S_ISDIR(smb_fname_parent->st.st_ex_mode)) {
118 if (get_current_uid(conn) == (uid_t)0) {
119 /* I'm sorry sir, I didn't know you were root... */
125 /* sticky bit means delete only by owner of file or by root or
126 * by owner of directory. */
127 if (smb_fname_parent->st.st_ex_mode & S_ISVTX) {
128 if(SMB_VFS_STAT(conn, smb_fname) != 0) {
129 if (errno == ENOENT) {
130 /* If the file doesn't already exist then
131 * yes we'll be able to delete it. */
135 DEBUG(10,("can_delete_file_in_directory: can't "
137 smb_fname_str_dbg(smb_fname),
144 * Patch from SATOH Fumiyasu <fumiyas@miraclelinux.com>
145 * for bug #3348. Don't assume owning sticky bit
146 * directory means write access allowed.
147 * Fail to delete if we're not the owner of the file,
148 * or the owner of the directory as we have no possible
149 * chance of deleting. Otherwise, go on and check the ACL.
151 if ((get_current_uid(conn) !=
152 smb_fname_parent->st.st_ex_uid) &&
153 (get_current_uid(conn) != smb_fname->st.st_ex_uid)) {
154 DEBUG(10,("can_delete_file_in_directory: not "
155 "owner of file %s or directory %s",
156 smb_fname_str_dbg(smb_fname),
157 smb_fname_str_dbg(smb_fname_parent)));
164 /* now for ACL checks */
167 * There's two ways to get the permission to delete a file: First by
168 * having the DELETE bit on the file itself and second if that does
169 * not help, by the DELETE_CHILD bit on the containing directory.
171 * Here we only check the directory permissions, we will
172 * check the file DELETE permission separately.
175 ret = can_access_file_acl(conn, smb_fname_parent, FILE_DELETE_CHILD);
178 TALLOC_FREE(smb_fname_parent);
182 /****************************************************************************
183 Actually emulate the in-kernel access checking for read/write access. We need
184 this to successfully check for ability to write for dos filetimes.
185 Note this doesn't take into account share write permissions.
186 ****************************************************************************/
188 bool can_access_file_data(connection_struct *conn,
189 const struct smb_filename *smb_fname,
192 if (!(access_mask & (FILE_READ_DATA|FILE_WRITE_DATA))) {
195 access_mask &= (FILE_READ_DATA|FILE_WRITE_DATA);
197 /* some fast paths first */
199 DEBUG(10,("can_access_file_data: requesting 0x%x on file %s\n",
200 (unsigned int)access_mask, smb_fname_str_dbg(smb_fname)));
202 if (get_current_uid(conn) == (uid_t)0) {
203 /* I'm sorry sir, I didn't know you were root... */
207 SMB_ASSERT(VALID_STAT(smb_fname->st));
209 /* Check primary owner access. */
210 if (get_current_uid(conn) == smb_fname->st.st_ex_uid) {
211 switch (access_mask) {
213 return (smb_fname->st.st_ex_mode & S_IRUSR) ?
216 case FILE_WRITE_DATA:
217 return (smb_fname->st.st_ex_mode & S_IWUSR) ?
220 default: /* FILE_READ_DATA|FILE_WRITE_DATA */
222 if ((smb_fname->st.st_ex_mode &
223 (S_IWUSR|S_IRUSR)) ==
232 /* now for ACL checks */
234 return can_access_file_acl(conn, smb_fname, access_mask);
237 /****************************************************************************
238 Userspace check for write access.
239 Note this doesn't take into account share write permissions.
240 ****************************************************************************/
242 bool can_write_to_file(connection_struct *conn,
243 const struct smb_filename *smb_fname)
245 return can_access_file_data(conn, smb_fname, FILE_WRITE_DATA);
248 /****************************************************************************
249 Check for an existing default Windows ACL on a directory.
250 ****************************************************************************/
252 bool directory_has_default_acl(connection_struct *conn, const char *fname)
254 /* returns talloced off tos. */
255 struct security_descriptor *secdesc = NULL;
257 NTSTATUS status = SMB_VFS_GET_NT_ACL(conn, fname,
258 SECINFO_DACL, &secdesc);
260 if (!NT_STATUS_IS_OK(status) || secdesc == NULL) {
264 for (i = 0; i < secdesc->dacl->num_aces; i++) {
265 struct security_ace *psa = &secdesc->dacl->aces[i];
266 if (psa->flags & (SEC_ACE_FLAG_OBJECT_INHERIT|
267 SEC_ACE_FLAG_CONTAINER_INHERIT)) {
268 TALLOC_FREE(secdesc);
272 TALLOC_FREE(secdesc);