1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3 * Copyright IBM Corporation, 2010
4 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5 */
6
7 #include <linux/module.h>
8 #include <linux/fs.h>
9 #include <net/9p/9p.h>
10 #include <net/9p/client.h>
11 #include <linux/slab.h>
12 #include <linux/sched.h>
13 #include <linux/posix_acl_xattr.h>
14 #include "xattr.h"
15 #include "acl.h"
16 #include "v9fs.h"
17 #include "v9fs_vfs.h"
18 #include "fid.h"
19
20 static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name)
21 {
22 ssize_t size;
23 void *value = NULL;
24 struct posix_acl *acl = NULL;
25
26 size = v9fs_fid_xattr_get(fid, name, NULL, 0);
27 if (size < 0)
28 return ERR_PTR(size);
29 if (size == 0)
30 return ERR_PTR(-ENODATA);
31
32 value = kzalloc(size, GFP_NOFS);
33 if (!value)
34 return ERR_PTR(-ENOMEM);
35
36 size = v9fs_fid_xattr_get(fid, name, value, size);
37 if (size < 0)
38 acl = ERR_PTR(size);
39 else if (size == 0)
40 acl = ERR_PTR(-ENODATA);
41 else
42 acl = posix_acl_from_xattr(&init_user_ns, value, size);
43 kfree(value);
44 return acl;
45 }
46
47 static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name)
48 {
49 struct p9_fid *fid;
50 struct posix_acl *acl = NULL;
51
52 fid = v9fs_fid_lookup(dentry);
53 if (IS_ERR(fid))
54 return ERR_CAST(fid);
55
56 acl = v9fs_fid_get_acl(fid, name);
57 p9_fid_put(fid);
58 return acl;
59 }
60
61 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name)
62 {
63 int retval;
64 struct posix_acl *acl = NULL;
65
66 acl = v9fs_fid_get_acl(fid, name);
67 if (!IS_ERR(acl))
68 return acl;
69
70 retval = PTR_ERR(acl);
71 if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP)
72 return NULL;
73
74 /* map everything else to -EIO */
75 return ERR_PTR(-EIO);
76 }
77
78 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
79 {
80 int retval = 0;
81 struct posix_acl *pacl, *dacl;
82 struct v9fs_session_info *v9ses;
83
84 v9ses = v9fs_inode2v9ses(inode);
85 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
86 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
87 set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
88 set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
89 return 0;
90 }
91 /* get the default/access acl values and cache them */
92 dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
93 pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
94
95 if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
96 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
97 set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
98 } else
99 retval = -EIO;
100
101 if (!IS_ERR(dacl))
102 posix_acl_release(dacl);
103
104 if (!IS_ERR(pacl))
105 posix_acl_release(pacl);
106
107 return retval;
108 }
109
110 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
111 {
112 struct posix_acl *acl;
113 /*
114 * 9p Always cache the acl value when
115 * instantiating the inode (v9fs_inode_from_fid)
116 */
117 acl = get_cached_acl(inode, type);
118 BUG_ON(is_uncached_acl(acl));
119 return acl;
120 }
121
122 struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu)
123 {
124 struct v9fs_session_info *v9ses;
125
126 if (rcu)
127 return ERR_PTR(-ECHILD);
128
129 v9ses = v9fs_inode2v9ses(inode);
130 if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
131 ((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
132 /*
133 * On access = client and acl = on mode get the acl
134 * values from the server
135 */
136 return NULL;
137 }
138 return v9fs_get_cached_acl(inode, type);
139
140 }
141
142 struct posix_acl *v9fs_iop_get_acl(struct mnt_idmap *idmap,
143 struct dentry *dentry, int type)
144 {
145 struct v9fs_session_info *v9ses;
146
147 v9ses = v9fs_dentry2v9ses(dentry);
148 /* We allow set/get/list of acl when access=client is not specified. */
149 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
150 return v9fs_acl_get(dentry, posix_acl_xattr_name(type));
151 return v9fs_get_cached_acl(d_inode(dentry), type);
152 }
153
154 int v9fs_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
155 struct posix_acl *acl, int type)
156 {
157 int retval;
158 size_t size = 0;
159 void *value = NULL;
160 const char *acl_name;
161 struct v9fs_session_info *v9ses;
162 struct inode *inode = d_inode(dentry);
163
164 if (acl) {
165 retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
166 if (retval)
167 goto err_out;
168
169 size = posix_acl_xattr_size(acl->a_count);
170
171 value = kzalloc(size, GFP_NOFS);
172 if (!value) {
173 retval = -ENOMEM;
174 goto err_out;
175 }
176
177 retval = posix_acl_to_xattr(&init_user_ns, acl, value, size);
178 if (retval < 0)
179 goto err_out;
180 }
181
182 /*
183 * set the attribute on the remote. Without even looking at the
184 * xattr value. We leave it to the server to validate
185 */
186 acl_name = posix_acl_xattr_name(type);
187 v9ses = v9fs_dentry2v9ses(dentry);
188 if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
189 retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
190 goto err_out;
191 }
192
193 if (S_ISLNK(inode->i_mode)) {
194 retval = -EOPNOTSUPP;
195 goto err_out;
196 }
197
198 if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
199 retval = -EPERM;
200 goto err_out;
201 }
202
203 switch (type) {
204 case ACL_TYPE_ACCESS:
205 if (acl) {
206 struct iattr iattr = {};
207 struct posix_acl *acl_mode = acl;
208
209 retval = posix_acl_update_mode(&nop_mnt_idmap, inode,
210 &iattr.ia_mode,
211 &acl_mode);
212 if (retval)
213 goto err_out;
214 if (!acl_mode) {
215 /*
216 * ACL can be represented by the mode bits.
217 * So don't update ACL below.
218 */
219 kfree(value);
220 value = NULL;
221 size = 0;
222 }
223 iattr.ia_valid = ATTR_MODE;
224 /*
225 * FIXME should we update ctime ?
226 * What is the following setxattr update the mode ?
227 */
228 v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
229 }
230 break;
231 case ACL_TYPE_DEFAULT:
232 if (!S_ISDIR(inode->i_mode)) {
233 retval = acl ? -EINVAL : 0;
234 goto err_out;
235 }
236 break;
237 }
238
239 retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
240 if (!retval)
241 set_cached_acl(inode, type, acl);
242
243 err_out:
244 kfree(value);
245 return retval;
246 }
247
248 static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
249 {
250 int retval;
251 char *name;
252 size_t size;
253 void *buffer;
254
255 if (!acl)
256 return 0;
257
258 /* Set a setxattr request to server */
259 size = posix_acl_xattr_size(acl->a_count);
260 buffer = kmalloc(size, GFP_KERNEL);
261 if (!buffer)
262 return -ENOMEM;
263 retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
264 if (retval < 0)
265 goto err_free_out;
266 switch (type) {
267 case ACL_TYPE_ACCESS:
268 name = XATTR_NAME_POSIX_ACL_ACCESS;
269 break;
270 case ACL_TYPE_DEFAULT:
271 name = XATTR_NAME_POSIX_ACL_DEFAULT;
272 break;
273 default:
274 BUG();
275 }
276 retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
277 err_free_out:
278 kfree(buffer);
279 return retval;
280 }
281
282 int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
283 {
284 int retval = 0;
285 struct posix_acl *acl;
286
287 if (S_ISLNK(inode->i_mode))
288 return -EOPNOTSUPP;
289 acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
290 if (acl) {
291 retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
292 if (retval)
293 return retval;
294 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
295 retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
296 posix_acl_release(acl);
297 }
298 return retval;
299 }
300
301 int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
302 struct posix_acl *dacl, struct posix_acl *acl)
303 {
304 set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
305 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
306 v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
307 v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
308 return 0;
309 }
310
311 void v9fs_put_acl(struct posix_acl *dacl,
312 struct posix_acl *acl)
313 {
314 posix_acl_release(dacl);
315 posix_acl_release(acl);
316 }
317
318 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
319 struct posix_acl **dpacl, struct posix_acl **pacl)
320 {
321 int retval = 0;
322 umode_t mode = *modep;
323 struct posix_acl *acl = NULL;
324
325 if (!S_ISLNK(mode)) {
326 acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
327 if (IS_ERR(acl))
328 return PTR_ERR(acl);
329 if (!acl)
330 mode &= ~current_umask();
331 }
332 if (acl) {
333 if (S_ISDIR(mode))
334 *dpacl = posix_acl_dup(acl);
335 retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
336 if (retval < 0)
337 return retval;
338 if (retval > 0)
339 *pacl = acl;
340 else
341 posix_acl_release(acl);
342 }
343 *modep = mode;
344 return 0;
345 }
346
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