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