1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* Extended attribute handling for AFS. We use xattrs to get and set metadata |
3 | * instead of providing pioctl(). |
4 | * |
5 | * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. |
6 | * Written by David Howells (dhowells@redhat.com) |
7 | */ |
8 | |
9 | #include <linux/slab.h> |
10 | #include <linux/fs.h> |
11 | #include <linux/xattr.h> |
12 | #include "internal.h" |
13 | |
14 | /* |
15 | * Deal with the result of a successful fetch ACL operation. |
16 | */ |
17 | static void afs_acl_success(struct afs_operation *op) |
18 | { |
19 | afs_vnode_commit_status(op, &op->file[0]); |
20 | } |
21 | |
22 | static void afs_acl_put(struct afs_operation *op) |
23 | { |
24 | kfree(objp: op->acl); |
25 | } |
26 | |
27 | static const struct afs_operation_ops afs_fetch_acl_operation = { |
28 | .issue_afs_rpc = afs_fs_fetch_acl, |
29 | .success = afs_acl_success, |
30 | .put = afs_acl_put, |
31 | }; |
32 | |
33 | /* |
34 | * Get a file's ACL. |
35 | */ |
36 | static int afs_xattr_get_acl(const struct xattr_handler *handler, |
37 | struct dentry *dentry, |
38 | struct inode *inode, const char *name, |
39 | void *buffer, size_t size) |
40 | { |
41 | struct afs_operation *op; |
42 | struct afs_vnode *vnode = AFS_FS_I(inode); |
43 | struct afs_acl *acl = NULL; |
44 | int ret; |
45 | |
46 | op = afs_alloc_operation(NULL, vnode->volume); |
47 | if (IS_ERR(ptr: op)) |
48 | return -ENOMEM; |
49 | |
50 | afs_op_set_vnode(op, n: 0, vnode); |
51 | op->ops = &afs_fetch_acl_operation; |
52 | |
53 | afs_begin_vnode_operation(op); |
54 | afs_wait_for_operation(op); |
55 | acl = op->acl; |
56 | op->acl = NULL; |
57 | ret = afs_put_operation(op); |
58 | |
59 | if (ret == 0) { |
60 | ret = acl->size; |
61 | if (size > 0) { |
62 | if (acl->size <= size) |
63 | memcpy(buffer, acl->data, acl->size); |
64 | else |
65 | ret = -ERANGE; |
66 | } |
67 | } |
68 | |
69 | kfree(objp: acl); |
70 | return ret; |
71 | } |
72 | |
73 | static bool afs_make_acl(struct afs_operation *op, |
74 | const void *buffer, size_t size) |
75 | { |
76 | struct afs_acl *acl; |
77 | |
78 | acl = kmalloc(size: sizeof(*acl) + size, GFP_KERNEL); |
79 | if (!acl) { |
80 | afs_op_nomem(op); |
81 | return false; |
82 | } |
83 | |
84 | acl->size = size; |
85 | memcpy(acl->data, buffer, size); |
86 | op->acl = acl; |
87 | return true; |
88 | } |
89 | |
90 | static const struct afs_operation_ops afs_store_acl_operation = { |
91 | .issue_afs_rpc = afs_fs_store_acl, |
92 | .success = afs_acl_success, |
93 | .put = afs_acl_put, |
94 | }; |
95 | |
96 | /* |
97 | * Set a file's AFS3 ACL. |
98 | */ |
99 | static int afs_xattr_set_acl(const struct xattr_handler *handler, |
100 | struct mnt_idmap *idmap, |
101 | struct dentry *dentry, |
102 | struct inode *inode, const char *name, |
103 | const void *buffer, size_t size, int flags) |
104 | { |
105 | struct afs_operation *op; |
106 | struct afs_vnode *vnode = AFS_FS_I(inode); |
107 | |
108 | if (flags == XATTR_CREATE) |
109 | return -EINVAL; |
110 | |
111 | op = afs_alloc_operation(NULL, vnode->volume); |
112 | if (IS_ERR(ptr: op)) |
113 | return -ENOMEM; |
114 | |
115 | afs_op_set_vnode(op, n: 0, vnode); |
116 | if (!afs_make_acl(op, buffer, size)) |
117 | return afs_put_operation(op); |
118 | |
119 | op->ops = &afs_store_acl_operation; |
120 | return afs_do_sync_operation(op); |
121 | } |
122 | |
123 | static const struct xattr_handler afs_xattr_afs_acl_handler = { |
124 | .name = "afs.acl" , |
125 | .get = afs_xattr_get_acl, |
126 | .set = afs_xattr_set_acl, |
127 | }; |
128 | |
129 | static const struct afs_operation_ops yfs_fetch_opaque_acl_operation = { |
130 | .issue_yfs_rpc = yfs_fs_fetch_opaque_acl, |
131 | .success = afs_acl_success, |
132 | /* Don't free op->yacl in .put here */ |
133 | }; |
134 | |
135 | /* |
136 | * Get a file's YFS ACL. |
137 | */ |
138 | static int afs_xattr_get_yfs(const struct xattr_handler *handler, |
139 | struct dentry *dentry, |
140 | struct inode *inode, const char *name, |
141 | void *buffer, size_t size) |
142 | { |
143 | struct afs_operation *op; |
144 | struct afs_vnode *vnode = AFS_FS_I(inode); |
145 | struct yfs_acl *yacl = NULL; |
146 | char buf[16], *data; |
147 | int which = 0, dsize, ret = -ENOMEM; |
148 | |
149 | if (strcmp(name, "acl" ) == 0) |
150 | which = 0; |
151 | else if (strcmp(name, "acl_inherited" ) == 0) |
152 | which = 1; |
153 | else if (strcmp(name, "acl_num_cleaned" ) == 0) |
154 | which = 2; |
155 | else if (strcmp(name, "vol_acl" ) == 0) |
156 | which = 3; |
157 | else |
158 | return -EOPNOTSUPP; |
159 | |
160 | yacl = kzalloc(size: sizeof(struct yfs_acl), GFP_KERNEL); |
161 | if (!yacl) |
162 | goto error; |
163 | |
164 | if (which == 0) |
165 | yacl->flags |= YFS_ACL_WANT_ACL; |
166 | else if (which == 3) |
167 | yacl->flags |= YFS_ACL_WANT_VOL_ACL; |
168 | |
169 | op = afs_alloc_operation(NULL, vnode->volume); |
170 | if (IS_ERR(ptr: op)) |
171 | goto error_yacl; |
172 | |
173 | afs_op_set_vnode(op, n: 0, vnode); |
174 | op->yacl = yacl; |
175 | op->ops = &yfs_fetch_opaque_acl_operation; |
176 | |
177 | afs_begin_vnode_operation(op); |
178 | afs_wait_for_operation(op); |
179 | ret = afs_put_operation(op); |
180 | |
181 | if (ret == 0) { |
182 | switch (which) { |
183 | case 0: |
184 | data = yacl->acl->data; |
185 | dsize = yacl->acl->size; |
186 | break; |
187 | case 1: |
188 | data = buf; |
189 | dsize = scnprintf(buf, size: sizeof(buf), fmt: "%u" , yacl->inherit_flag); |
190 | break; |
191 | case 2: |
192 | data = buf; |
193 | dsize = scnprintf(buf, size: sizeof(buf), fmt: "%u" , yacl->num_cleaned); |
194 | break; |
195 | case 3: |
196 | data = yacl->vol_acl->data; |
197 | dsize = yacl->vol_acl->size; |
198 | break; |
199 | default: |
200 | ret = -EOPNOTSUPP; |
201 | goto error_yacl; |
202 | } |
203 | |
204 | ret = dsize; |
205 | if (size > 0) { |
206 | if (dsize <= size) |
207 | memcpy(buffer, data, dsize); |
208 | else |
209 | ret = -ERANGE; |
210 | } |
211 | } else if (ret == -ENOTSUPP) { |
212 | ret = -ENODATA; |
213 | } |
214 | |
215 | error_yacl: |
216 | yfs_free_opaque_acl(yacl); |
217 | error: |
218 | return ret; |
219 | } |
220 | |
221 | static const struct afs_operation_ops yfs_store_opaque_acl2_operation = { |
222 | .issue_yfs_rpc = yfs_fs_store_opaque_acl2, |
223 | .success = afs_acl_success, |
224 | .put = afs_acl_put, |
225 | }; |
226 | |
227 | /* |
228 | * Set a file's YFS ACL. |
229 | */ |
230 | static int afs_xattr_set_yfs(const struct xattr_handler *handler, |
231 | struct mnt_idmap *idmap, |
232 | struct dentry *dentry, |
233 | struct inode *inode, const char *name, |
234 | const void *buffer, size_t size, int flags) |
235 | { |
236 | struct afs_operation *op; |
237 | struct afs_vnode *vnode = AFS_FS_I(inode); |
238 | int ret; |
239 | |
240 | if (flags == XATTR_CREATE || |
241 | strcmp(name, "acl" ) != 0) |
242 | return -EINVAL; |
243 | |
244 | op = afs_alloc_operation(NULL, vnode->volume); |
245 | if (IS_ERR(ptr: op)) |
246 | return -ENOMEM; |
247 | |
248 | afs_op_set_vnode(op, n: 0, vnode); |
249 | if (!afs_make_acl(op, buffer, size)) |
250 | return afs_put_operation(op); |
251 | |
252 | op->ops = &yfs_store_opaque_acl2_operation; |
253 | ret = afs_do_sync_operation(op); |
254 | if (ret == -ENOTSUPP) |
255 | ret = -ENODATA; |
256 | return ret; |
257 | } |
258 | |
259 | static const struct xattr_handler afs_xattr_yfs_handler = { |
260 | .prefix = "afs.yfs." , |
261 | .get = afs_xattr_get_yfs, |
262 | .set = afs_xattr_set_yfs, |
263 | }; |
264 | |
265 | /* |
266 | * Get the name of the cell on which a file resides. |
267 | */ |
268 | static int afs_xattr_get_cell(const struct xattr_handler *handler, |
269 | struct dentry *dentry, |
270 | struct inode *inode, const char *name, |
271 | void *buffer, size_t size) |
272 | { |
273 | struct afs_vnode *vnode = AFS_FS_I(inode); |
274 | struct afs_cell *cell = vnode->volume->cell; |
275 | size_t namelen; |
276 | |
277 | namelen = cell->name_len; |
278 | if (size == 0) |
279 | return namelen; |
280 | if (namelen > size) |
281 | return -ERANGE; |
282 | memcpy(buffer, cell->name, namelen); |
283 | return namelen; |
284 | } |
285 | |
286 | static const struct xattr_handler afs_xattr_afs_cell_handler = { |
287 | .name = "afs.cell" , |
288 | .get = afs_xattr_get_cell, |
289 | }; |
290 | |
291 | /* |
292 | * Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of |
293 | * hex numbers separated by colons. |
294 | */ |
295 | static int afs_xattr_get_fid(const struct xattr_handler *handler, |
296 | struct dentry *dentry, |
297 | struct inode *inode, const char *name, |
298 | void *buffer, size_t size) |
299 | { |
300 | struct afs_vnode *vnode = AFS_FS_I(inode); |
301 | char text[16 + 1 + 24 + 1 + 8 + 1]; |
302 | size_t len; |
303 | |
304 | /* The volume ID is 64-bit, the vnode ID is 96-bit and the |
305 | * uniquifier is 32-bit. |
306 | */ |
307 | len = scnprintf(buf: text, size: sizeof(text), fmt: "%llx:" , vnode->fid.vid); |
308 | if (vnode->fid.vnode_hi) |
309 | len += scnprintf(buf: text + len, size: sizeof(text) - len, fmt: "%x%016llx" , |
310 | vnode->fid.vnode_hi, vnode->fid.vnode); |
311 | else |
312 | len += scnprintf(buf: text + len, size: sizeof(text) - len, fmt: "%llx" , |
313 | vnode->fid.vnode); |
314 | len += scnprintf(buf: text + len, size: sizeof(text) - len, fmt: ":%x" , |
315 | vnode->fid.unique); |
316 | |
317 | if (size == 0) |
318 | return len; |
319 | if (len > size) |
320 | return -ERANGE; |
321 | memcpy(buffer, text, len); |
322 | return len; |
323 | } |
324 | |
325 | static const struct xattr_handler afs_xattr_afs_fid_handler = { |
326 | .name = "afs.fid" , |
327 | .get = afs_xattr_get_fid, |
328 | }; |
329 | |
330 | /* |
331 | * Get the name of the volume on which a file resides. |
332 | */ |
333 | static int afs_xattr_get_volume(const struct xattr_handler *handler, |
334 | struct dentry *dentry, |
335 | struct inode *inode, const char *name, |
336 | void *buffer, size_t size) |
337 | { |
338 | struct afs_vnode *vnode = AFS_FS_I(inode); |
339 | const char *volname = vnode->volume->name; |
340 | size_t namelen; |
341 | |
342 | namelen = strlen(volname); |
343 | if (size == 0) |
344 | return namelen; |
345 | if (namelen > size) |
346 | return -ERANGE; |
347 | memcpy(buffer, volname, namelen); |
348 | return namelen; |
349 | } |
350 | |
351 | static const struct xattr_handler afs_xattr_afs_volume_handler = { |
352 | .name = "afs.volume" , |
353 | .get = afs_xattr_get_volume, |
354 | }; |
355 | |
356 | const struct xattr_handler * const afs_xattr_handlers[] = { |
357 | &afs_xattr_afs_acl_handler, |
358 | &afs_xattr_afs_cell_handler, |
359 | &afs_xattr_afs_fid_handler, |
360 | &afs_xattr_afs_volume_handler, |
361 | &afs_xattr_yfs_handler, /* afs.yfs. prefix */ |
362 | NULL |
363 | }; |
364 | |