1 /*
2 * Copyright IBM Corporation, 2010
3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of version 2.1 of the GNU Lesser General Public License
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12 *
13 */
14
15 #include <linux/module.h>
16 #include <linux/fs.h>
17 #include <net/9p/9p.h>
18 #include <net/9p/client.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
21 #include <linux/posix_acl_xattr.h>
22 #include "xattr.h"
23 #include "acl.h"
24 #include "v9fs.h"
25 #include "v9fs_vfs.h"
26 #include "fid.h"
27
__v9fs_get_acl(struct p9_fid * fid,char * name)28 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
29 {
30 ssize_t size;
31 void *value = NULL;
32 struct posix_acl *acl = NULL;
33
34 size = v9fs_fid_xattr_get(fid, name, NULL, 0);
35 if (size > 0) {
36 value = kzalloc(size, GFP_NOFS);
37 if (!value)
38 return ERR_PTR(-ENOMEM);
39 size = v9fs_fid_xattr_get(fid, name, value, size);
40 if (size > 0) {
41 acl = posix_acl_from_xattr(&init_user_ns, value, size);
42 if (IS_ERR(acl))
43 goto err_out;
44 }
45 } else if (size == -ENODATA || size == 0 ||
46 size == -ENOSYS || size == -EOPNOTSUPP) {
47 acl = NULL;
48 } else
49 acl = ERR_PTR(-EIO);
50
51 err_out:
52 kfree(value);
53 return acl;
54 }
55
v9fs_get_acl(struct inode * inode,struct p9_fid * fid)56 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
57 {
58 int retval = 0;
59 struct posix_acl *pacl, *dacl;
60 struct v9fs_session_info *v9ses;
61
62 v9ses = v9fs_inode2v9ses(inode);
63 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
64 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
65 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
66 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
67 return 0;
68 }
69 /* get the default/access acl values and cache them */
70 dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
71 pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
72
73 if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
74 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
75 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
76 } else
77 retval = -EIO;
78
79 if (!IS_ERR(dacl))
80 posix_acl_release(dacl);
81
82 if (!IS_ERR(pacl))
83 posix_acl_release(pacl);
84
85 return retval;
86 }
87
v9fs_get_cached_acl(struct inode * inode,int type)88 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
89 {
90 struct posix_acl *acl;
91 /*
92 * 9p Always cache the acl value when
93 * instantiating the inode (v9fs_inode_from_fid)
94 */
95 acl = get_cached_acl(inode, type);
96 BUG_ON(is_uncached_acl(acl));
97 return acl;
98 }
99
v9fs_iop_get_acl(struct inode * inode,int type,bool rcu)100 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type, bool rcu)
101 {
102 struct v9fs_session_info *v9ses;
103
104 if (rcu)
105 return ERR_PTR(-ECHILD);
106
107 v9ses = v9fs_inode2v9ses(inode);
108 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
109 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
110 /*
111 * On access = client and acl = on mode get the acl
112 * values from the server
113 */
114 return NULL;
115 }
116 return v9fs_get_cached_acl(inode, type);
117
118 }
119
v9fs_set_acl(struct p9_fid * fid,int type,struct posix_acl * acl)120 static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
121 {
122 int retval;
123 char *name;
124 size_t size;
125 void *buffer;
126 if (!acl)
127 return 0;
128
129 /* Set a setxattr request to server */
130 size = posix_acl_xattr_size(acl->a_count);
131 buffer = kmalloc(size, GFP_KERNEL);
132 if (!buffer)
133 return -ENOMEM;
134 retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
135 if (retval < 0)
136 goto err_free_out;
137 switch (type) {
138 case ACL_TYPE_ACCESS:
139 name = XATTR_NAME_POSIX_ACL_ACCESS;
140 break;
141 case ACL_TYPE_DEFAULT:
142 name = XATTR_NAME_POSIX_ACL_DEFAULT;
143 break;
144 default:
145 BUG();
146 }
147 retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
148 err_free_out:
149 kfree(buffer);
150 return retval;
151 }
152
v9fs_acl_chmod(struct inode * inode,struct p9_fid * fid)153 int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
154 {
155 int retval = 0;
156 struct posix_acl *acl;
157
158 if (S_ISLNK(inode->i_mode))
159 return -EOPNOTSUPP;
160 acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
161 if (acl) {
162 retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
163 if (retval)
164 return retval;
165 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
166 retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
167 posix_acl_release(acl);
168 }
169 return retval;
170 }
171
v9fs_set_create_acl(struct inode * inode,struct p9_fid * fid,struct posix_acl * dacl,struct posix_acl * acl)172 int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
173 struct posix_acl *dacl, struct posix_acl *acl)
174 {
175 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
176 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
177 v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
178 v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
179 return 0;
180 }
181
v9fs_put_acl(struct posix_acl * dacl,struct posix_acl * acl)182 void v9fs_put_acl(struct posix_acl *dacl,
183 struct posix_acl *acl)
184 {
185 posix_acl_release(dacl);
186 posix_acl_release(acl);
187 }
188
v9fs_acl_mode(struct inode * dir,umode_t * modep,struct posix_acl ** dpacl,struct posix_acl ** pacl)189 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
190 struct posix_acl **dpacl, struct posix_acl **pacl)
191 {
192 int retval = 0;
193 umode_t mode = *modep;
194 struct posix_acl *acl = NULL;
195
196 if (!S_ISLNK(mode)) {
197 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
198 if (IS_ERR(acl))
199 return PTR_ERR(acl);
200 if (!acl)
201 mode &= ~current_umask();
202 }
203 if (acl) {
204 if (S_ISDIR(mode))
205 *dpacl = posix_acl_dup(acl);
206 retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
207 if (retval < 0)
208 return retval;
209 if (retval > 0)
210 *pacl = acl;
211 else
212 posix_acl_release(acl);
213 }
214 *modep = mode;
215 return 0;
216 }
217
v9fs_xattr_get_acl(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * buffer,size_t size)218 static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
219 struct dentry *dentry, struct inode *inode,
220 const char *name, void *buffer, size_t size)
221 {
222 struct v9fs_session_info *v9ses;
223 struct posix_acl *acl;
224 int error;
225
226 v9ses = v9fs_dentry2v9ses(dentry);
227 /*
228 * We allow set/get/list of acl when access=client is not specified
229 */
230 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
231 return v9fs_xattr_get(dentry, handler->name, buffer, size);
232
233 acl = v9fs_get_cached_acl(inode, handler->flags);
234 if (IS_ERR(acl))
235 return PTR_ERR(acl);
236 if (acl == NULL)
237 return -ENODATA;
238 error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
239 posix_acl_release(acl);
240
241 return error;
242 }
243
v9fs_xattr_set_acl(const struct xattr_handler * handler,struct user_namespace * mnt_userns,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)244 static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
245 struct user_namespace *mnt_userns,
246 struct dentry *dentry, struct inode *inode,
247 const char *name, const void *value,
248 size_t size, int flags)
249 {
250 int retval;
251 struct posix_acl *acl;
252 struct v9fs_session_info *v9ses;
253
254 v9ses = v9fs_dentry2v9ses(dentry);
255 /*
256 * set the attribute on the remote. Without even looking at the
257 * xattr value. We leave it to the server to validate
258 */
259 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
260 return v9fs_xattr_set(dentry, handler->name, value, size,
261 flags);
262
263 if (S_ISLNK(inode->i_mode))
264 return -EOPNOTSUPP;
265 if (!inode_owner_or_capable(&init_user_ns, inode))
266 return -EPERM;
267 if (value) {
268 /* update the cached acl value */
269 acl = posix_acl_from_xattr(&init_user_ns, value, size);
270 if (IS_ERR(acl))
271 return PTR_ERR(acl);
272 else if (acl) {
273 retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
274 if (retval)
275 goto err_out;
276 }
277 } else
278 acl = NULL;
279
280 switch (handler->flags) {
281 case ACL_TYPE_ACCESS:
282 if (acl) {
283 struct iattr iattr = { 0 };
284 struct posix_acl *old_acl = acl;
285
286 retval = posix_acl_update_mode(&init_user_ns, inode,
287 &iattr.ia_mode, &acl);
288 if (retval)
289 goto err_out;
290 if (!acl) {
291 /*
292 * ACL can be represented
293 * by the mode bits. So don't
294 * update ACL.
295 */
296 posix_acl_release(old_acl);
297 value = NULL;
298 size = 0;
299 }
300 iattr.ia_valid = ATTR_MODE;
301 /* FIXME should we update ctime ?
302 * What is the following setxattr update the
303 * mode ?
304 */
305 v9fs_vfs_setattr_dotl(&init_user_ns, dentry, &iattr);
306 }
307 break;
308 case ACL_TYPE_DEFAULT:
309 if (!S_ISDIR(inode->i_mode)) {
310 retval = acl ? -EINVAL : 0;
311 goto err_out;
312 }
313 break;
314 default:
315 BUG();
316 }
317 retval = v9fs_xattr_set(dentry, handler->name, value, size, flags);
318 if (!retval)
319 set_cached_acl(inode, handler->flags, acl);
320 err_out:
321 posix_acl_release(acl);
322 return retval;
323 }
324
325 const struct xattr_handler v9fs_xattr_acl_access_handler = {
326 .name = XATTR_NAME_POSIX_ACL_ACCESS,
327 .flags = ACL_TYPE_ACCESS,
328 .get = v9fs_xattr_get_acl,
329 .set = v9fs_xattr_set_acl,
330 };
331
332 const struct xattr_handler v9fs_xattr_acl_default_handler = {
333 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
334 .flags = ACL_TYPE_DEFAULT,
335 .get = v9fs_xattr_get_acl,
336 .set = v9fs_xattr_set_acl,
337 };
338
