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
__v9fs_get_acl(struct p9_fid * fid,char * name)27 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
28 {
29 ssize_t size;
30 void *value = NULL;
31 struct posix_acl *acl = NULL;
32
33 size = v9fs_fid_xattr_get(fid, name, NULL, 0);
34 if (size > 0) {
35 value = kzalloc(size, GFP_NOFS);
36 if (!value)
37 return ERR_PTR(-ENOMEM);
38 size = v9fs_fid_xattr_get(fid, name, value, size);
39 if (size > 0) {
40 acl = posix_acl_from_xattr(value, size);
41 if (IS_ERR(acl))
42 goto err_out;
43 }
44 } else if (size == -ENODATA || size == 0 ||
45 size == -ENOSYS || size == -EOPNOTSUPP) {
46 acl = NULL;
47 } else
48 acl = ERR_PTR(-EIO);
49
50 err_out:
51 kfree(value);
52 return acl;
53 }
54
v9fs_get_acl(struct inode * inode,struct p9_fid * fid)55 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
56 {
57 int retval = 0;
58 struct posix_acl *pacl, *dacl;
59 struct v9fs_session_info *v9ses;
60
61 v9ses = v9fs_inode2v9ses(inode);
62 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
63 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
64 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
65 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
66 return 0;
67 }
68 /* get the default/access acl values and cache them */
69 dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
70 pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
71
72 if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
73 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
74 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
75 } else
76 retval = -EIO;
77
78 if (!IS_ERR(dacl))
79 posix_acl_release(dacl);
80
81 if (!IS_ERR(pacl))
82 posix_acl_release(pacl);
83
84 return retval;
85 }
86
v9fs_get_cached_acl(struct inode * inode,int type)87 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
88 {
89 struct posix_acl *acl;
90 /*
91 * 9p Always cache the acl value when
92 * instantiating the inode (v9fs_inode_from_fid)
93 */
94 acl = get_cached_acl(inode, type);
95 BUG_ON(acl == ACL_NOT_CACHED);
96 return acl;
97 }
98
v9fs_iop_get_acl(struct inode * inode,int type)99 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type)
100 {
101 struct v9fs_session_info *v9ses;
102
103 v9ses = v9fs_inode2v9ses(inode);
104 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
105 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
106 /*
107 * On access = client and acl = on mode get the acl
108 * values from the server
109 */
110 return NULL;
111 }
112 return v9fs_get_cached_acl(inode, type);
113
114 }
115
v9fs_set_acl(struct dentry * dentry,int type,struct posix_acl * acl)116 static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
117 {
118 int retval;
119 char *name;
120 size_t size;
121 void *buffer;
122 struct inode *inode = dentry->d_inode;
123
124 set_cached_acl(inode, type, acl);
125
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(acl, buffer, size);
135 if (retval < 0)
136 goto err_free_out;
137 switch (type) {
138 case ACL_TYPE_ACCESS:
139 name = POSIX_ACL_XATTR_ACCESS;
140 break;
141 case ACL_TYPE_DEFAULT:
142 name = POSIX_ACL_XATTR_DEFAULT;
143 break;
144 default:
145 BUG();
146 }
147 retval = v9fs_xattr_set(dentry, name, buffer, size, 0);
148 err_free_out:
149 kfree(buffer);
150 return retval;
151 }
152
v9fs_acl_chmod(struct dentry * dentry)153 int v9fs_acl_chmod(struct dentry *dentry)
154 {
155 int retval = 0;
156 struct posix_acl *acl;
157 struct inode *inode = dentry->d_inode;
158
159 if (S_ISLNK(inode->i_mode))
160 return -EOPNOTSUPP;
161 acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
162 if (acl) {
163 retval = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
164 if (retval)
165 return retval;
166 retval = v9fs_set_acl(dentry, ACL_TYPE_ACCESS, acl);
167 posix_acl_release(acl);
168 }
169 return retval;
170 }
171
v9fs_set_create_acl(struct dentry * dentry,struct posix_acl ** dpacl,struct posix_acl ** pacl)172 int v9fs_set_create_acl(struct dentry *dentry,
173 struct posix_acl **dpacl, struct posix_acl **pacl)
174 {
175 if (dentry) {
176 v9fs_set_acl(dentry, ACL_TYPE_DEFAULT, *dpacl);
177 v9fs_set_acl(dentry, ACL_TYPE_ACCESS, *pacl);
178 }
179 posix_acl_release(*dpacl);
180 posix_acl_release(*pacl);
181 *dpacl = *pacl = NULL;
182 return 0;
183 }
184
v9fs_acl_mode(struct inode * dir,umode_t * modep,struct posix_acl ** dpacl,struct posix_acl ** pacl)185 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
186 struct posix_acl **dpacl, struct posix_acl **pacl)
187 {
188 int retval = 0;
189 umode_t mode = *modep;
190 struct posix_acl *acl = NULL;
191
192 if (!S_ISLNK(mode)) {
193 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
194 if (IS_ERR(acl))
195 return PTR_ERR(acl);
196 if (!acl)
197 mode &= ~current_umask();
198 }
199 if (acl) {
200 if (S_ISDIR(mode))
201 *dpacl = posix_acl_dup(acl);
202 retval = posix_acl_create(&acl, GFP_NOFS, &mode);
203 if (retval < 0)
204 return retval;
205 if (retval > 0)
206 *pacl = acl;
207 else
208 posix_acl_release(acl);
209 }
210 *modep = mode;
211 return 0;
212 }
213
v9fs_remote_get_acl(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)214 static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
215 void *buffer, size_t size, int type)
216 {
217 char *full_name;
218
219 switch (type) {
220 case ACL_TYPE_ACCESS:
221 full_name = POSIX_ACL_XATTR_ACCESS;
222 break;
223 case ACL_TYPE_DEFAULT:
224 full_name = POSIX_ACL_XATTR_DEFAULT;
225 break;
226 default:
227 BUG();
228 }
229 return v9fs_xattr_get(dentry, full_name, buffer, size);
230 }
231
v9fs_xattr_get_acl(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)232 static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
233 void *buffer, size_t size, int type)
234 {
235 struct v9fs_session_info *v9ses;
236 struct posix_acl *acl;
237 int error;
238
239 if (strcmp(name, "") != 0)
240 return -EINVAL;
241
242 v9ses = v9fs_dentry2v9ses(dentry);
243 /*
244 * We allow set/get/list of acl when access=client is not specified
245 */
246 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
247 return v9fs_remote_get_acl(dentry, name, buffer, size, type);
248
249 acl = v9fs_get_cached_acl(dentry->d_inode, type);
250 if (IS_ERR(acl))
251 return PTR_ERR(acl);
252 if (acl == NULL)
253 return -ENODATA;
254 error = posix_acl_to_xattr(acl, buffer, size);
255 posix_acl_release(acl);
256
257 return error;
258 }
259
v9fs_remote_set_acl(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)260 static int v9fs_remote_set_acl(struct dentry *dentry, const char *name,
261 const void *value, size_t size,
262 int flags, int type)
263 {
264 char *full_name;
265
266 switch (type) {
267 case ACL_TYPE_ACCESS:
268 full_name = POSIX_ACL_XATTR_ACCESS;
269 break;
270 case ACL_TYPE_DEFAULT:
271 full_name = POSIX_ACL_XATTR_DEFAULT;
272 break;
273 default:
274 BUG();
275 }
276 return v9fs_xattr_set(dentry, full_name, value, size, flags);
277 }
278
279
v9fs_xattr_set_acl(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)280 static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
281 const void *value, size_t size,
282 int flags, int type)
283 {
284 int retval;
285 struct posix_acl *acl;
286 struct v9fs_session_info *v9ses;
287 struct inode *inode = dentry->d_inode;
288
289 if (strcmp(name, "") != 0)
290 return -EINVAL;
291
292 v9ses = v9fs_dentry2v9ses(dentry);
293 /*
294 * set the attribute on the remote. Without even looking at the
295 * xattr value. We leave it to the server to validate
296 */
297 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
298 return v9fs_remote_set_acl(dentry, name,
299 value, size, flags, type);
300
301 if (S_ISLNK(inode->i_mode))
302 return -EOPNOTSUPP;
303 if (!inode_owner_or_capable(inode))
304 return -EPERM;
305 if (value) {
306 /* update the cached acl value */
307 acl = posix_acl_from_xattr(value, size);
308 if (IS_ERR(acl))
309 return PTR_ERR(acl);
310 else if (acl) {
311 retval = posix_acl_valid(acl);
312 if (retval)
313 goto err_out;
314 }
315 } else
316 acl = NULL;
317
318 switch (type) {
319 case ACL_TYPE_ACCESS:
320 name = POSIX_ACL_XATTR_ACCESS;
321 if (acl) {
322 umode_t mode = inode->i_mode;
323 retval = posix_acl_equiv_mode(acl, &mode);
324 if (retval < 0)
325 goto err_out;
326 else {
327 struct iattr iattr;
328 if (retval == 0) {
329 /*
330 * ACL can be represented
331 * by the mode bits. So don't
332 * update ACL.
333 */
334 acl = NULL;
335 value = NULL;
336 size = 0;
337 }
338 /* Updte the mode bits */
339 iattr.ia_mode = ((mode & S_IALLUGO) |
340 (inode->i_mode & ~S_IALLUGO));
341 iattr.ia_valid = ATTR_MODE;
342 /* FIXME should we update ctime ?
343 * What is the following setxattr update the
344 * mode ?
345 */
346 v9fs_vfs_setattr_dotl(dentry, &iattr);
347 }
348 }
349 break;
350 case ACL_TYPE_DEFAULT:
351 name = POSIX_ACL_XATTR_DEFAULT;
352 if (!S_ISDIR(inode->i_mode)) {
353 retval = acl ? -EINVAL : 0;
354 goto err_out;
355 }
356 break;
357 default:
358 BUG();
359 }
360 retval = v9fs_xattr_set(dentry, name, value, size, flags);
361 if (!retval)
362 set_cached_acl(inode, type, acl);
363 err_out:
364 posix_acl_release(acl);
365 return retval;
366 }
367
368 const struct xattr_handler v9fs_xattr_acl_access_handler = {
369 .prefix = POSIX_ACL_XATTR_ACCESS,
370 .flags = ACL_TYPE_ACCESS,
371 .get = v9fs_xattr_get_acl,
372 .set = v9fs_xattr_set_acl,
373 };
374
375 const struct xattr_handler v9fs_xattr_acl_default_handler = {
376 .prefix = POSIX_ACL_XATTR_DEFAULT,
377 .flags = ACL_TYPE_DEFAULT,
378 .get = v9fs_xattr_get_acl,
379 .set = v9fs_xattr_set_acl,
380 };
381