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 const 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 if (!lp_acl_check_permissions(SNUM(conn))) {
96 /* This option means don't check. */
100 /* Get the parent directory permission mask and owners. */
101 if (!parent_dirname(ctx, smb_fname->base_name, &dname, NULL)) {
105 status = create_synthetic_smb_fname(ctx, dname, NULL, NULL,
107 if (!NT_STATUS_IS_OK(status)) {
112 if(SMB_VFS_STAT(conn, smb_fname_parent) != 0) {
117 /* fast paths first */
119 if (!S_ISDIR(smb_fname_parent->st.st_ex_mode)) {
123 if (get_current_uid(conn) == (uid_t)0) {
124 /* I'm sorry sir, I didn't know you were root... */
130 /* sticky bit means delete only by owner of file or by root or
131 * by owner of directory. */
132 if (smb_fname_parent->st.st_ex_mode & S_ISVTX) {
133 if (!VALID_STAT(smb_fname->st)) {
134 /* If the file doesn't already exist then
135 * yes we'll be able to delete it. */
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);