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Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
77b14db5 EB |
2 | /* |
3 | * /proc/sys support | |
4 | */ | |
1e0edd3f | 5 | #include <linux/init.h> |
77b14db5 | 6 | #include <linux/sysctl.h> |
f1ecf068 | 7 | #include <linux/poll.h> |
77b14db5 | 8 | #include <linux/proc_fs.h> |
87ebdc00 | 9 | #include <linux/printk.h> |
77b14db5 | 10 | #include <linux/security.h> |
40401530 | 11 | #include <linux/sched.h> |
5b825c3a | 12 | #include <linux/cred.h> |
34286d66 | 13 | #include <linux/namei.h> |
40401530 | 14 | #include <linux/mm.h> |
4bd6a735 | 15 | #include <linux/uio.h> |
1f87f0b5 | 16 | #include <linux/module.h> |
7b146ceb | 17 | #include <linux/bpf-cgroup.h> |
3db978d4 | 18 | #include <linux/mount.h> |
3ddd9a80 | 19 | #include <linux/kmemleak.h> |
77b14db5 EB |
20 | #include "internal.h" |
21 | ||
cb55f27a MT |
22 | #define list_for_each_table_entry(entry, table) \ |
23 | for ((entry) = (table); (entry)->procname; (entry)++) | |
24 | ||
d72f71eb | 25 | static const struct dentry_operations proc_sys_dentry_operations; |
77b14db5 | 26 | static const struct file_operations proc_sys_file_operations; |
03a44825 | 27 | static const struct inode_operations proc_sys_inode_operations; |
9043476f AV |
28 | static const struct file_operations proc_sys_dir_file_operations; |
29 | static const struct inode_operations proc_sys_dir_operations; | |
77b14db5 | 30 | |
eec4844f | 31 | /* shared constants to be used in various sysctls */ |
4c7f24f8 | 32 | const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 }; |
eec4844f MC |
33 | EXPORT_SYMBOL(sysctl_vals); |
34 | ||
b1f2aff8 LC |
35 | const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX }; |
36 | EXPORT_SYMBOL_GPL(sysctl_long_vals); | |
37 | ||
f9bd6733 EB |
38 | /* Support for permanently empty directories */ |
39 | ||
40 | struct ctl_table sysctl_mount_point[] = { | |
41 | { } | |
42 | }; | |
43 | ||
ee9efac4 LC |
44 | /** |
45 | * register_sysctl_mount_point() - registers a sysctl mount point | |
46 | * @path: path for the mount point | |
47 | * | |
48 | * Used to create a permanently empty directory to serve as mount point. | |
49 | * There are some subtle but important permission checks this allows in the | |
50 | * case of unprivileged mounts. | |
51 | */ | |
52 | struct ctl_table_header *register_sysctl_mount_point(const char *path) | |
53 | { | |
54 | return register_sysctl(path, sysctl_mount_point); | |
55 | } | |
56 | EXPORT_SYMBOL(register_sysctl_mount_point); | |
57 | ||
f9bd6733 EB |
58 | static bool is_empty_dir(struct ctl_table_header *head) |
59 | { | |
60 | return head->ctl_table[0].child == sysctl_mount_point; | |
61 | } | |
62 | ||
63 | static void set_empty_dir(struct ctl_dir *dir) | |
64 | { | |
65 | dir->header.ctl_table[0].child = sysctl_mount_point; | |
66 | } | |
67 | ||
68 | static void clear_empty_dir(struct ctl_dir *dir) | |
69 | ||
70 | { | |
71 | dir->header.ctl_table[0].child = NULL; | |
72 | } | |
73 | ||
f1ecf068 LDM |
74 | void proc_sys_poll_notify(struct ctl_table_poll *poll) |
75 | { | |
76 | if (!poll) | |
77 | return; | |
78 | ||
79 | atomic_inc(&poll->event); | |
80 | wake_up_interruptible(&poll->wait); | |
81 | } | |
82 | ||
a194558e EB |
83 | static struct ctl_table root_table[] = { |
84 | { | |
85 | .procname = "", | |
7ec66d06 | 86 | .mode = S_IFDIR|S_IRUGO|S_IXUGO, |
a194558e EB |
87 | }, |
88 | { } | |
89 | }; | |
0e47c99d | 90 | static struct ctl_table_root sysctl_table_root = { |
0e47c99d | 91 | .default_set.dir.header = { |
7ec66d06 EB |
92 | {{.count = 1, |
93 | .nreg = 1, | |
ac13ac6f | 94 | .ctl_table = root_table }}, |
0e47c99d | 95 | .ctl_table_arg = root_table, |
7ec66d06 EB |
96 | .root = &sysctl_table_root, |
97 | .set = &sysctl_table_root.default_set, | |
98 | }, | |
1f87f0b5 | 99 | }; |
1f87f0b5 EB |
100 | |
101 | static DEFINE_SPINLOCK(sysctl_lock); | |
102 | ||
7ec66d06 | 103 | static void drop_sysctl_table(struct ctl_table_header *header); |
0e47c99d | 104 | static int sysctl_follow_link(struct ctl_table_header **phead, |
13bcc6a2 | 105 | struct ctl_table **pentry); |
0e47c99d EB |
106 | static int insert_links(struct ctl_table_header *head); |
107 | static void put_links(struct ctl_table_header *header); | |
7ec66d06 | 108 | |
6980128f EB |
109 | static void sysctl_print_dir(struct ctl_dir *dir) |
110 | { | |
111 | if (dir->header.parent) | |
112 | sysctl_print_dir(dir->header.parent); | |
87ebdc00 | 113 | pr_cont("%s/", dir->header.ctl_table[0].procname); |
6980128f EB |
114 | } |
115 | ||
076c3eed EB |
116 | static int namecmp(const char *name1, int len1, const char *name2, int len2) |
117 | { | |
076c3eed EB |
118 | int cmp; |
119 | ||
d8fc9b66 | 120 | cmp = memcmp(name1, name2, min(len1, len2)); |
076c3eed EB |
121 | if (cmp == 0) |
122 | cmp = len1 - len2; | |
123 | return cmp; | |
124 | } | |
125 | ||
60f126d9 | 126 | /* Called under sysctl_lock */ |
076c3eed | 127 | static struct ctl_table *find_entry(struct ctl_table_header **phead, |
0e47c99d | 128 | struct ctl_dir *dir, const char *name, int namelen) |
076c3eed EB |
129 | { |
130 | struct ctl_table_header *head; | |
131 | struct ctl_table *entry; | |
ac13ac6f | 132 | struct rb_node *node = dir->root.rb_node; |
076c3eed | 133 | |
ac13ac6f EB |
134 | while (node) |
135 | { | |
136 | struct ctl_node *ctl_node; | |
137 | const char *procname; | |
138 | int cmp; | |
139 | ||
140 | ctl_node = rb_entry(node, struct ctl_node, node); | |
141 | head = ctl_node->header; | |
142 | entry = &head->ctl_table[ctl_node - head->node]; | |
143 | procname = entry->procname; | |
144 | ||
145 | cmp = namecmp(name, namelen, procname, strlen(procname)); | |
146 | if (cmp < 0) | |
147 | node = node->rb_left; | |
148 | else if (cmp > 0) | |
149 | node = node->rb_right; | |
150 | else { | |
151 | *phead = head; | |
152 | return entry; | |
076c3eed EB |
153 | } |
154 | } | |
155 | return NULL; | |
156 | } | |
157 | ||
ac13ac6f EB |
158 | static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) |
159 | { | |
160 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
161 | struct rb_node **p = &head->parent->root.rb_node; | |
162 | struct rb_node *parent = NULL; | |
163 | const char *name = entry->procname; | |
164 | int namelen = strlen(name); | |
165 | ||
166 | while (*p) { | |
167 | struct ctl_table_header *parent_head; | |
168 | struct ctl_table *parent_entry; | |
169 | struct ctl_node *parent_node; | |
170 | const char *parent_name; | |
171 | int cmp; | |
172 | ||
173 | parent = *p; | |
174 | parent_node = rb_entry(parent, struct ctl_node, node); | |
175 | parent_head = parent_node->header; | |
176 | parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; | |
177 | parent_name = parent_entry->procname; | |
178 | ||
179 | cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); | |
180 | if (cmp < 0) | |
181 | p = &(*p)->rb_left; | |
182 | else if (cmp > 0) | |
183 | p = &(*p)->rb_right; | |
184 | else { | |
87ebdc00 | 185 | pr_err("sysctl duplicate entry: "); |
ac13ac6f | 186 | sysctl_print_dir(head->parent); |
153ee1c4 | 187 | pr_cont("%s\n", entry->procname); |
ac13ac6f EB |
188 | return -EEXIST; |
189 | } | |
190 | } | |
191 | ||
192 | rb_link_node(node, parent, p); | |
ea5272f5 | 193 | rb_insert_color(node, &head->parent->root); |
ac13ac6f EB |
194 | return 0; |
195 | } | |
196 | ||
197 | static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) | |
198 | { | |
199 | struct rb_node *node = &head->node[entry - head->ctl_table].node; | |
200 | ||
201 | rb_erase(node, &head->parent->root); | |
202 | } | |
203 | ||
e0d04529 EB |
204 | static void init_header(struct ctl_table_header *head, |
205 | struct ctl_table_root *root, struct ctl_table_set *set, | |
ac13ac6f | 206 | struct ctl_node *node, struct ctl_table *table) |
e0d04529 | 207 | { |
7ec66d06 | 208 | head->ctl_table = table; |
e0d04529 | 209 | head->ctl_table_arg = table; |
e0d04529 EB |
210 | head->used = 0; |
211 | head->count = 1; | |
212 | head->nreg = 1; | |
213 | head->unregistering = NULL; | |
214 | head->root = root; | |
215 | head->set = set; | |
216 | head->parent = NULL; | |
ac13ac6f | 217 | head->node = node; |
2fd1d2c4 | 218 | INIT_HLIST_HEAD(&head->inodes); |
ac13ac6f EB |
219 | if (node) { |
220 | struct ctl_table *entry; | |
cb55f27a MT |
221 | |
222 | list_for_each_table_entry(entry, table) { | |
ac13ac6f | 223 | node->header = head; |
cb55f27a MT |
224 | node++; |
225 | } | |
ac13ac6f | 226 | } |
e0d04529 EB |
227 | } |
228 | ||
8425d6aa EB |
229 | static void erase_header(struct ctl_table_header *head) |
230 | { | |
ac13ac6f | 231 | struct ctl_table *entry; |
cb55f27a MT |
232 | |
233 | list_for_each_table_entry(entry, head->ctl_table) | |
ac13ac6f | 234 | erase_entry(head, entry); |
8425d6aa EB |
235 | } |
236 | ||
0e47c99d | 237 | static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) |
8425d6aa | 238 | { |
ac13ac6f | 239 | struct ctl_table *entry; |
0e47c99d EB |
240 | int err; |
241 | ||
f9bd6733 EB |
242 | /* Is this a permanently empty directory? */ |
243 | if (is_empty_dir(&dir->header)) | |
244 | return -EROFS; | |
245 | ||
246 | /* Am I creating a permanently empty directory? */ | |
247 | if (header->ctl_table == sysctl_mount_point) { | |
248 | if (!RB_EMPTY_ROOT(&dir->root)) | |
249 | return -EINVAL; | |
250 | set_empty_dir(dir); | |
251 | } | |
252 | ||
0e47c99d | 253 | dir->header.nreg++; |
7ec66d06 | 254 | header->parent = dir; |
0e47c99d EB |
255 | err = insert_links(header); |
256 | if (err) | |
257 | goto fail_links; | |
cb55f27a | 258 | list_for_each_table_entry(entry, header->ctl_table) { |
ac13ac6f EB |
259 | err = insert_entry(header, entry); |
260 | if (err) | |
261 | goto fail; | |
262 | } | |
0e47c99d | 263 | return 0; |
ac13ac6f EB |
264 | fail: |
265 | erase_header(header); | |
266 | put_links(header); | |
0e47c99d | 267 | fail_links: |
f9bd6733 EB |
268 | if (header->ctl_table == sysctl_mount_point) |
269 | clear_empty_dir(dir); | |
0e47c99d EB |
270 | header->parent = NULL; |
271 | drop_sysctl_table(&dir->header); | |
272 | return err; | |
8425d6aa EB |
273 | } |
274 | ||
1f87f0b5 EB |
275 | /* called under sysctl_lock */ |
276 | static int use_table(struct ctl_table_header *p) | |
277 | { | |
278 | if (unlikely(p->unregistering)) | |
279 | return 0; | |
280 | p->used++; | |
281 | return 1; | |
282 | } | |
283 | ||
284 | /* called under sysctl_lock */ | |
285 | static void unuse_table(struct ctl_table_header *p) | |
286 | { | |
287 | if (!--p->used) | |
288 | if (unlikely(p->unregistering)) | |
289 | complete(p->unregistering); | |
290 | } | |
291 | ||
f90f3caf | 292 | static void proc_sys_invalidate_dcache(struct ctl_table_header *head) |
d6cffbbe | 293 | { |
f90f3caf | 294 | proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); |
d6cffbbe KK |
295 | } |
296 | ||
1f87f0b5 EB |
297 | /* called under sysctl_lock, will reacquire if has to wait */ |
298 | static void start_unregistering(struct ctl_table_header *p) | |
299 | { | |
300 | /* | |
301 | * if p->used is 0, nobody will ever touch that entry again; | |
302 | * we'll eliminate all paths to it before dropping sysctl_lock | |
303 | */ | |
304 | if (unlikely(p->used)) { | |
305 | struct completion wait; | |
306 | init_completion(&wait); | |
307 | p->unregistering = &wait; | |
308 | spin_unlock(&sysctl_lock); | |
309 | wait_for_completion(&wait); | |
1f87f0b5 EB |
310 | } else { |
311 | /* anything non-NULL; we'll never dereference it */ | |
312 | p->unregistering = ERR_PTR(-EINVAL); | |
ace0c791 | 313 | spin_unlock(&sysctl_lock); |
1f87f0b5 | 314 | } |
d6cffbbe | 315 | /* |
f90f3caf | 316 | * Invalidate dentries for unregistered sysctls: namespaced sysctls |
d6cffbbe KK |
317 | * can have duplicate names and contaminate dcache very badly. |
318 | */ | |
f90f3caf | 319 | proc_sys_invalidate_dcache(p); |
1f87f0b5 EB |
320 | /* |
321 | * do not remove from the list until nobody holds it; walking the | |
322 | * list in do_sysctl() relies on that. | |
323 | */ | |
ace0c791 | 324 | spin_lock(&sysctl_lock); |
8425d6aa | 325 | erase_header(p); |
1f87f0b5 EB |
326 | } |
327 | ||
1f87f0b5 EB |
328 | static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) |
329 | { | |
ab4a1f24 | 330 | BUG_ON(!head); |
1f87f0b5 EB |
331 | spin_lock(&sysctl_lock); |
332 | if (!use_table(head)) | |
333 | head = ERR_PTR(-ENOENT); | |
334 | spin_unlock(&sysctl_lock); | |
335 | return head; | |
336 | } | |
337 | ||
338 | static void sysctl_head_finish(struct ctl_table_header *head) | |
339 | { | |
340 | if (!head) | |
341 | return; | |
342 | spin_lock(&sysctl_lock); | |
343 | unuse_table(head); | |
344 | spin_unlock(&sysctl_lock); | |
345 | } | |
346 | ||
347 | static struct ctl_table_set * | |
13bcc6a2 | 348 | lookup_header_set(struct ctl_table_root *root) |
1f87f0b5 EB |
349 | { |
350 | struct ctl_table_set *set = &root->default_set; | |
351 | if (root->lookup) | |
13bcc6a2 | 352 | set = root->lookup(root); |
1f87f0b5 EB |
353 | return set; |
354 | } | |
355 | ||
076c3eed | 356 | static struct ctl_table *lookup_entry(struct ctl_table_header **phead, |
7ec66d06 | 357 | struct ctl_dir *dir, |
076c3eed EB |
358 | const char *name, int namelen) |
359 | { | |
360 | struct ctl_table_header *head; | |
361 | struct ctl_table *entry; | |
076c3eed EB |
362 | |
363 | spin_lock(&sysctl_lock); | |
0e47c99d EB |
364 | entry = find_entry(&head, dir, name, namelen); |
365 | if (entry && use_table(head)) | |
366 | *phead = head; | |
367 | else | |
368 | entry = NULL; | |
076c3eed EB |
369 | spin_unlock(&sysctl_lock); |
370 | return entry; | |
371 | } | |
372 | ||
ac13ac6f | 373 | static struct ctl_node *first_usable_entry(struct rb_node *node) |
1f87f0b5 | 374 | { |
ac13ac6f | 375 | struct ctl_node *ctl_node; |
1f87f0b5 | 376 | |
ac13ac6f EB |
377 | for (;node; node = rb_next(node)) { |
378 | ctl_node = rb_entry(node, struct ctl_node, node); | |
379 | if (use_table(ctl_node->header)) | |
380 | return ctl_node; | |
1f87f0b5 | 381 | } |
1f87f0b5 EB |
382 | return NULL; |
383 | } | |
384 | ||
7ec66d06 | 385 | static void first_entry(struct ctl_dir *dir, |
6a75ce16 EB |
386 | struct ctl_table_header **phead, struct ctl_table **pentry) |
387 | { | |
ac13ac6f | 388 | struct ctl_table_header *head = NULL; |
7ec66d06 | 389 | struct ctl_table *entry = NULL; |
ac13ac6f | 390 | struct ctl_node *ctl_node; |
6a75ce16 EB |
391 | |
392 | spin_lock(&sysctl_lock); | |
ac13ac6f | 393 | ctl_node = first_usable_entry(rb_first(&dir->root)); |
6a75ce16 | 394 | spin_unlock(&sysctl_lock); |
ac13ac6f EB |
395 | if (ctl_node) { |
396 | head = ctl_node->header; | |
397 | entry = &head->ctl_table[ctl_node - head->node]; | |
398 | } | |
6a75ce16 EB |
399 | *phead = head; |
400 | *pentry = entry; | |
401 | } | |
402 | ||
7ec66d06 | 403 | static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) |
1f87f0b5 | 404 | { |
6a75ce16 EB |
405 | struct ctl_table_header *head = *phead; |
406 | struct ctl_table *entry = *pentry; | |
ac13ac6f | 407 | struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; |
6a75ce16 | 408 | |
ac13ac6f EB |
409 | spin_lock(&sysctl_lock); |
410 | unuse_table(head); | |
411 | ||
412 | ctl_node = first_usable_entry(rb_next(&ctl_node->node)); | |
413 | spin_unlock(&sysctl_lock); | |
414 | head = NULL; | |
415 | if (ctl_node) { | |
416 | head = ctl_node->header; | |
417 | entry = &head->ctl_table[ctl_node - head->node]; | |
6a75ce16 EB |
418 | } |
419 | *phead = head; | |
420 | *pentry = entry; | |
1f87f0b5 EB |
421 | } |
422 | ||
1f87f0b5 EB |
423 | /* |
424 | * sysctl_perm does NOT grant the superuser all rights automatically, because | |
425 | * some sysctl variables are readonly even to root. | |
426 | */ | |
427 | ||
428 | static int test_perm(int mode, int op) | |
429 | { | |
091bd3ea | 430 | if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) |
1f87f0b5 | 431 | mode >>= 6; |
091bd3ea | 432 | else if (in_egroup_p(GLOBAL_ROOT_GID)) |
1f87f0b5 EB |
433 | mode >>= 3; |
434 | if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) | |
435 | return 0; | |
436 | return -EACCES; | |
437 | } | |
438 | ||
73f7ef43 | 439 | static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) |
1f87f0b5 | 440 | { |
73f7ef43 | 441 | struct ctl_table_root *root = head->root; |
1f87f0b5 EB |
442 | int mode; |
443 | ||
444 | if (root->permissions) | |
73f7ef43 | 445 | mode = root->permissions(head, table); |
1f87f0b5 EB |
446 | else |
447 | mode = table->mode; | |
448 | ||
449 | return test_perm(mode, op); | |
450 | } | |
451 | ||
9043476f AV |
452 | static struct inode *proc_sys_make_inode(struct super_block *sb, |
453 | struct ctl_table_header *head, struct ctl_table *table) | |
77b14db5 | 454 | { |
e79c6a4f | 455 | struct ctl_table_root *root = head->root; |
77b14db5 | 456 | struct inode *inode; |
9043476f | 457 | struct proc_inode *ei; |
77b14db5 | 458 | |
9043476f | 459 | inode = new_inode(sb); |
77b14db5 | 460 | if (!inode) |
ea5751cc | 461 | return ERR_PTR(-ENOMEM); |
77b14db5 | 462 | |
85fe4025 CH |
463 | inode->i_ino = get_next_ino(); |
464 | ||
77b14db5 | 465 | ei = PROC_I(inode); |
9043476f | 466 | |
d6cffbbe | 467 | spin_lock(&sysctl_lock); |
ace0c791 EB |
468 | if (unlikely(head->unregistering)) { |
469 | spin_unlock(&sysctl_lock); | |
470 | iput(inode); | |
ea5751cc | 471 | return ERR_PTR(-ENOENT); |
ace0c791 EB |
472 | } |
473 | ei->sysctl = head; | |
474 | ei->sysctl_entry = table; | |
0afa5ca8 | 475 | hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); |
d6cffbbe KK |
476 | head->count++; |
477 | spin_unlock(&sysctl_lock); | |
478 | ||
078cd827 | 479 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
9043476f | 480 | inode->i_mode = table->mode; |
7ec66d06 | 481 | if (!S_ISDIR(table->mode)) { |
9043476f AV |
482 | inode->i_mode |= S_IFREG; |
483 | inode->i_op = &proc_sys_inode_operations; | |
484 | inode->i_fop = &proc_sys_file_operations; | |
485 | } else { | |
486 | inode->i_mode |= S_IFDIR; | |
9043476f AV |
487 | inode->i_op = &proc_sys_dir_operations; |
488 | inode->i_fop = &proc_sys_dir_file_operations; | |
f9bd6733 EB |
489 | if (is_empty_dir(head)) |
490 | make_empty_dir_inode(inode); | |
9043476f | 491 | } |
e79c6a4f DT |
492 | |
493 | if (root->set_ownership) | |
494 | root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); | |
5ec27ec7 RB |
495 | else { |
496 | inode->i_uid = GLOBAL_ROOT_UID; | |
497 | inode->i_gid = GLOBAL_ROOT_GID; | |
498 | } | |
e79c6a4f | 499 | |
77b14db5 EB |
500 | return inode; |
501 | } | |
502 | ||
d6cffbbe KK |
503 | void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) |
504 | { | |
505 | spin_lock(&sysctl_lock); | |
0afa5ca8 | 506 | hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); |
d6cffbbe KK |
507 | if (!--head->count) |
508 | kfree_rcu(head, rcu); | |
509 | spin_unlock(&sysctl_lock); | |
510 | } | |
511 | ||
81324364 | 512 | static struct ctl_table_header *grab_header(struct inode *inode) |
77b14db5 | 513 | { |
3cc3e046 EB |
514 | struct ctl_table_header *head = PROC_I(inode)->sysctl; |
515 | if (!head) | |
0e47c99d | 516 | head = &sysctl_table_root.default_set.dir.header; |
3cc3e046 | 517 | return sysctl_head_grab(head); |
9043476f | 518 | } |
77b14db5 | 519 | |
9043476f | 520 | static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, |
00cd8dd3 | 521 | unsigned int flags) |
9043476f AV |
522 | { |
523 | struct ctl_table_header *head = grab_header(dir); | |
9043476f | 524 | struct ctl_table_header *h = NULL; |
dc12e909 | 525 | const struct qstr *name = &dentry->d_name; |
9043476f AV |
526 | struct ctl_table *p; |
527 | struct inode *inode; | |
528 | struct dentry *err = ERR_PTR(-ENOENT); | |
7ec66d06 | 529 | struct ctl_dir *ctl_dir; |
0e47c99d | 530 | int ret; |
77b14db5 | 531 | |
9043476f AV |
532 | if (IS_ERR(head)) |
533 | return ERR_CAST(head); | |
77b14db5 | 534 | |
7ec66d06 | 535 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 | 536 | |
7ec66d06 | 537 | p = lookup_entry(&h, ctl_dir, name->name, name->len); |
9043476f | 538 | if (!p) |
77b14db5 EB |
539 | goto out; |
540 | ||
4e757320 | 541 | if (S_ISLNK(p->mode)) { |
13bcc6a2 | 542 | ret = sysctl_follow_link(&h, &p); |
4e757320 EB |
543 | err = ERR_PTR(ret); |
544 | if (ret) | |
545 | goto out; | |
546 | } | |
0e47c99d | 547 | |
9043476f | 548 | inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); |
ea5751cc ID |
549 | if (IS_ERR(inode)) { |
550 | err = ERR_CAST(inode); | |
77b14db5 | 551 | goto out; |
ea5751cc | 552 | } |
77b14db5 | 553 | |
fb045adb | 554 | d_set_d_op(dentry, &proc_sys_dentry_operations); |
888e2b03 | 555 | err = d_splice_alias(inode, dentry); |
77b14db5 EB |
556 | |
557 | out: | |
6bf61045 FR |
558 | if (h) |
559 | sysctl_head_finish(h); | |
77b14db5 EB |
560 | sysctl_head_finish(head); |
561 | return err; | |
562 | } | |
563 | ||
4bd6a735 MWO |
564 | static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, |
565 | int write) | |
77b14db5 | 566 | { |
4bd6a735 | 567 | struct inode *inode = file_inode(iocb->ki_filp); |
9043476f AV |
568 | struct ctl_table_header *head = grab_header(inode); |
569 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
4bd6a735 MWO |
570 | size_t count = iov_iter_count(iter); |
571 | char *kbuf; | |
2a2da53b | 572 | ssize_t error; |
77b14db5 | 573 | |
9043476f AV |
574 | if (IS_ERR(head)) |
575 | return PTR_ERR(head); | |
77b14db5 EB |
576 | |
577 | /* | |
578 | * At this point we know that the sysctl was not unregistered | |
579 | * and won't be until we finish. | |
580 | */ | |
581 | error = -EPERM; | |
73f7ef43 | 582 | if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) |
77b14db5 EB |
583 | goto out; |
584 | ||
9043476f AV |
585 | /* if that can happen at all, it should be -EINVAL, not -EISDIR */ |
586 | error = -EINVAL; | |
587 | if (!table->proc_handler) | |
588 | goto out; | |
589 | ||
ef9d965b | 590 | /* don't even try if the size is too large */ |
d4d80e69 MWO |
591 | error = -ENOMEM; |
592 | if (count >= KMALLOC_MAX_SIZE) | |
593 | goto out; | |
45089437 | 594 | kbuf = kvzalloc(count + 1, GFP_KERNEL); |
4bd6a735 MWO |
595 | if (!kbuf) |
596 | goto out; | |
ef9d965b | 597 | |
32927393 | 598 | if (write) { |
4bd6a735 MWO |
599 | error = -EFAULT; |
600 | if (!copy_from_iter_full(kbuf, count, iter)) | |
601 | goto out_free_buf; | |
602 | kbuf[count] = '\0'; | |
32927393 CH |
603 | } |
604 | ||
605 | error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, | |
4bd6a735 | 606 | &iocb->ki_pos); |
7b146ceb | 607 | if (error) |
32927393 | 608 | goto out_free_buf; |
7b146ceb | 609 | |
77b14db5 | 610 | /* careful: calling conventions are nasty here */ |
4bd6a735 | 611 | error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); |
32927393 CH |
612 | if (error) |
613 | goto out_free_buf; | |
614 | ||
615 | if (!write) { | |
616 | error = -EFAULT; | |
4bd6a735 | 617 | if (copy_to_iter(kbuf, count, iter) < count) |
32927393 | 618 | goto out_free_buf; |
4e63acdf AI |
619 | } |
620 | ||
32927393 CH |
621 | error = count; |
622 | out_free_buf: | |
45089437 | 623 | kvfree(kbuf); |
77b14db5 EB |
624 | out: |
625 | sysctl_head_finish(head); | |
626 | ||
627 | return error; | |
628 | } | |
629 | ||
4bd6a735 | 630 | static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) |
77b14db5 | 631 | { |
4bd6a735 | 632 | return proc_sys_call_handler(iocb, iter, 0); |
7708bfb1 | 633 | } |
77b14db5 | 634 | |
4bd6a735 | 635 | static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) |
7708bfb1 | 636 | { |
4bd6a735 | 637 | return proc_sys_call_handler(iocb, iter, 1); |
77b14db5 EB |
638 | } |
639 | ||
f1ecf068 LDM |
640 | static int proc_sys_open(struct inode *inode, struct file *filp) |
641 | { | |
4e474a00 | 642 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 LDM |
643 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
644 | ||
4e474a00 LDM |
645 | /* sysctl was unregistered */ |
646 | if (IS_ERR(head)) | |
647 | return PTR_ERR(head); | |
648 | ||
f1ecf068 LDM |
649 | if (table->poll) |
650 | filp->private_data = proc_sys_poll_event(table->poll); | |
651 | ||
4e474a00 LDM |
652 | sysctl_head_finish(head); |
653 | ||
f1ecf068 LDM |
654 | return 0; |
655 | } | |
656 | ||
076ccb76 | 657 | static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) |
f1ecf068 | 658 | { |
496ad9aa | 659 | struct inode *inode = file_inode(filp); |
4e474a00 | 660 | struct ctl_table_header *head = grab_header(inode); |
f1ecf068 | 661 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; |
076ccb76 | 662 | __poll_t ret = DEFAULT_POLLMASK; |
4e474a00 LDM |
663 | unsigned long event; |
664 | ||
665 | /* sysctl was unregistered */ | |
666 | if (IS_ERR(head)) | |
a9a08845 | 667 | return EPOLLERR | EPOLLHUP; |
f1ecf068 LDM |
668 | |
669 | if (!table->proc_handler) | |
670 | goto out; | |
671 | ||
672 | if (!table->poll) | |
673 | goto out; | |
674 | ||
4e474a00 | 675 | event = (unsigned long)filp->private_data; |
f1ecf068 LDM |
676 | poll_wait(filp, &table->poll->wait, wait); |
677 | ||
678 | if (event != atomic_read(&table->poll->event)) { | |
679 | filp->private_data = proc_sys_poll_event(table->poll); | |
a9a08845 | 680 | ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; |
f1ecf068 LDM |
681 | } |
682 | ||
683 | out: | |
4e474a00 LDM |
684 | sysctl_head_finish(head); |
685 | ||
f1ecf068 LDM |
686 | return ret; |
687 | } | |
77b14db5 | 688 | |
f0c3b509 AV |
689 | static bool proc_sys_fill_cache(struct file *file, |
690 | struct dir_context *ctx, | |
9043476f AV |
691 | struct ctl_table_header *head, |
692 | struct ctl_table *table) | |
77b14db5 | 693 | { |
f0c3b509 | 694 | struct dentry *child, *dir = file->f_path.dentry; |
77b14db5 EB |
695 | struct inode *inode; |
696 | struct qstr qname; | |
697 | ino_t ino = 0; | |
698 | unsigned type = DT_UNKNOWN; | |
77b14db5 EB |
699 | |
700 | qname.name = table->procname; | |
701 | qname.len = strlen(table->procname); | |
8387ff25 | 702 | qname.hash = full_name_hash(dir, qname.name, qname.len); |
77b14db5 | 703 | |
77b14db5 EB |
704 | child = d_lookup(dir, &qname); |
705 | if (!child) { | |
76aab3ab AV |
706 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); |
707 | child = d_alloc_parallel(dir, &qname, &wq); | |
708 | if (IS_ERR(child)) | |
709 | return false; | |
710 | if (d_in_lookup(child)) { | |
888e2b03 | 711 | struct dentry *res; |
9043476f | 712 | inode = proc_sys_make_inode(dir->d_sb, head, table); |
ea5751cc | 713 | if (IS_ERR(inode)) { |
76aab3ab | 714 | d_lookup_done(child); |
9043476f | 715 | dput(child); |
f0c3b509 | 716 | return false; |
77b14db5 | 717 | } |
76aab3ab | 718 | d_set_d_op(child, &proc_sys_dentry_operations); |
888e2b03 AV |
719 | res = d_splice_alias(inode, child); |
720 | d_lookup_done(child); | |
721 | if (unlikely(res)) { | |
722 | if (IS_ERR(res)) { | |
723 | dput(child); | |
724 | return false; | |
725 | } | |
726 | dput(child); | |
727 | child = res; | |
728 | } | |
77b14db5 EB |
729 | } |
730 | } | |
2b0143b5 | 731 | inode = d_inode(child); |
9043476f AV |
732 | ino = inode->i_ino; |
733 | type = inode->i_mode >> 12; | |
77b14db5 | 734 | dput(child); |
f0c3b509 | 735 | return dir_emit(ctx, qname.name, qname.len, ino, type); |
9043476f AV |
736 | } |
737 | ||
f0c3b509 AV |
738 | static bool proc_sys_link_fill_cache(struct file *file, |
739 | struct dir_context *ctx, | |
0e47c99d EB |
740 | struct ctl_table_header *head, |
741 | struct ctl_table *table) | |
742 | { | |
f0c3b509 | 743 | bool ret = true; |
a0b0d1c3 | 744 | |
0e47c99d | 745 | head = sysctl_head_grab(head); |
a0b0d1c3 DK |
746 | if (IS_ERR(head)) |
747 | return false; | |
0e47c99d | 748 | |
835b94e0 DK |
749 | /* It is not an error if we can not follow the link ignore it */ |
750 | if (sysctl_follow_link(&head, &table)) | |
751 | goto out; | |
0e47c99d | 752 | |
f0c3b509 | 753 | ret = proc_sys_fill_cache(file, ctx, head, table); |
0e47c99d EB |
754 | out: |
755 | sysctl_head_finish(head); | |
756 | return ret; | |
757 | } | |
758 | ||
e5eea098 | 759 | static int scan(struct ctl_table_header *head, struct ctl_table *table, |
9043476f | 760 | unsigned long *pos, struct file *file, |
f0c3b509 | 761 | struct dir_context *ctx) |
9043476f | 762 | { |
f0c3b509 | 763 | bool res; |
9043476f | 764 | |
f0c3b509 AV |
765 | if ((*pos)++ < ctx->pos) |
766 | return true; | |
9043476f | 767 | |
0e47c99d | 768 | if (unlikely(S_ISLNK(table->mode))) |
f0c3b509 | 769 | res = proc_sys_link_fill_cache(file, ctx, head, table); |
0e47c99d | 770 | else |
f0c3b509 | 771 | res = proc_sys_fill_cache(file, ctx, head, table); |
9043476f | 772 | |
f0c3b509 AV |
773 | if (res) |
774 | ctx->pos = *pos; | |
9043476f | 775 | |
6a75ce16 | 776 | return res; |
77b14db5 EB |
777 | } |
778 | ||
f0c3b509 | 779 | static int proc_sys_readdir(struct file *file, struct dir_context *ctx) |
77b14db5 | 780 | { |
f0c3b509 | 781 | struct ctl_table_header *head = grab_header(file_inode(file)); |
9043476f | 782 | struct ctl_table_header *h = NULL; |
6a75ce16 | 783 | struct ctl_table *entry; |
7ec66d06 | 784 | struct ctl_dir *ctl_dir; |
77b14db5 | 785 | unsigned long pos; |
9043476f AV |
786 | |
787 | if (IS_ERR(head)) | |
788 | return PTR_ERR(head); | |
77b14db5 | 789 | |
7ec66d06 | 790 | ctl_dir = container_of(head, struct ctl_dir, header); |
77b14db5 | 791 | |
f0c3b509 | 792 | if (!dir_emit_dots(file, ctx)) |
93362fa4 | 793 | goto out; |
f0c3b509 | 794 | |
77b14db5 EB |
795 | pos = 2; |
796 | ||
7ec66d06 | 797 | for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { |
f0c3b509 | 798 | if (!scan(h, entry, &pos, file, ctx)) { |
9043476f AV |
799 | sysctl_head_finish(h); |
800 | break; | |
77b14db5 EB |
801 | } |
802 | } | |
93362fa4 | 803 | out: |
77b14db5 | 804 | sysctl_head_finish(head); |
f0c3b509 | 805 | return 0; |
77b14db5 EB |
806 | } |
807 | ||
549c7297 CB |
808 | static int proc_sys_permission(struct user_namespace *mnt_userns, |
809 | struct inode *inode, int mask) | |
77b14db5 EB |
810 | { |
811 | /* | |
812 | * sysctl entries that are not writeable, | |
813 | * are _NOT_ writeable, capabilities or not. | |
814 | */ | |
f696a365 MS |
815 | struct ctl_table_header *head; |
816 | struct ctl_table *table; | |
77b14db5 EB |
817 | int error; |
818 | ||
f696a365 MS |
819 | /* Executable files are not allowed under /proc/sys/ */ |
820 | if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) | |
821 | return -EACCES; | |
822 | ||
823 | head = grab_header(inode); | |
9043476f AV |
824 | if (IS_ERR(head)) |
825 | return PTR_ERR(head); | |
77b14db5 | 826 | |
f696a365 | 827 | table = PROC_I(inode)->sysctl_entry; |
9043476f AV |
828 | if (!table) /* global root - r-xr-xr-x */ |
829 | error = mask & MAY_WRITE ? -EACCES : 0; | |
830 | else /* Use the permissions on the sysctl table entry */ | |
73f7ef43 | 831 | error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); |
77b14db5 | 832 | |
77b14db5 EB |
833 | sysctl_head_finish(head); |
834 | return error; | |
835 | } | |
836 | ||
549c7297 CB |
837 | static int proc_sys_setattr(struct user_namespace *mnt_userns, |
838 | struct dentry *dentry, struct iattr *attr) | |
77b14db5 | 839 | { |
2b0143b5 | 840 | struct inode *inode = d_inode(dentry); |
77b14db5 EB |
841 | int error; |
842 | ||
843 | if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) | |
844 | return -EPERM; | |
845 | ||
2f221d6f | 846 | error = setattr_prepare(&init_user_ns, dentry, attr); |
1025774c CH |
847 | if (error) |
848 | return error; | |
849 | ||
2f221d6f | 850 | setattr_copy(&init_user_ns, inode, attr); |
1025774c CH |
851 | mark_inode_dirty(inode); |
852 | return 0; | |
77b14db5 EB |
853 | } |
854 | ||
549c7297 CB |
855 | static int proc_sys_getattr(struct user_namespace *mnt_userns, |
856 | const struct path *path, struct kstat *stat, | |
a528d35e | 857 | u32 request_mask, unsigned int query_flags) |
9043476f | 858 | { |
a528d35e | 859 | struct inode *inode = d_inode(path->dentry); |
9043476f AV |
860 | struct ctl_table_header *head = grab_header(inode); |
861 | struct ctl_table *table = PROC_I(inode)->sysctl_entry; | |
862 | ||
863 | if (IS_ERR(head)) | |
864 | return PTR_ERR(head); | |
865 | ||
0d56a451 | 866 | generic_fillattr(&init_user_ns, inode, stat); |
9043476f AV |
867 | if (table) |
868 | stat->mode = (stat->mode & S_IFMT) | table->mode; | |
869 | ||
870 | sysctl_head_finish(head); | |
871 | return 0; | |
872 | } | |
873 | ||
77b14db5 | 874 | static const struct file_operations proc_sys_file_operations = { |
f1ecf068 LDM |
875 | .open = proc_sys_open, |
876 | .poll = proc_sys_poll, | |
4bd6a735 MWO |
877 | .read_iter = proc_sys_read, |
878 | .write_iter = proc_sys_write, | |
879 | .splice_read = generic_file_splice_read, | |
880 | .splice_write = iter_file_splice_write, | |
6038f373 | 881 | .llseek = default_llseek, |
9043476f AV |
882 | }; |
883 | ||
884 | static const struct file_operations proc_sys_dir_file_operations = { | |
887df078 | 885 | .read = generic_read_dir, |
f50752ea | 886 | .iterate_shared = proc_sys_readdir, |
3222a3e5 | 887 | .llseek = generic_file_llseek, |
77b14db5 EB |
888 | }; |
889 | ||
03a44825 | 890 | static const struct inode_operations proc_sys_inode_operations = { |
9043476f AV |
891 | .permission = proc_sys_permission, |
892 | .setattr = proc_sys_setattr, | |
893 | .getattr = proc_sys_getattr, | |
894 | }; | |
895 | ||
896 | static const struct inode_operations proc_sys_dir_operations = { | |
77b14db5 EB |
897 | .lookup = proc_sys_lookup, |
898 | .permission = proc_sys_permission, | |
899 | .setattr = proc_sys_setattr, | |
9043476f | 900 | .getattr = proc_sys_getattr, |
77b14db5 EB |
901 | }; |
902 | ||
0b728e19 | 903 | static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) |
77b14db5 | 904 | { |
0b728e19 | 905 | if (flags & LOOKUP_RCU) |
34286d66 | 906 | return -ECHILD; |
2b0143b5 | 907 | return !PROC_I(d_inode(dentry))->sysctl->unregistering; |
9043476f AV |
908 | } |
909 | ||
fe15ce44 | 910 | static int proc_sys_delete(const struct dentry *dentry) |
9043476f | 911 | { |
2b0143b5 | 912 | return !!PROC_I(d_inode(dentry))->sysctl->unregistering; |
9043476f AV |
913 | } |
914 | ||
1f87f0b5 EB |
915 | static int sysctl_is_seen(struct ctl_table_header *p) |
916 | { | |
917 | struct ctl_table_set *set = p->set; | |
918 | int res; | |
919 | spin_lock(&sysctl_lock); | |
920 | if (p->unregistering) | |
921 | res = 0; | |
922 | else if (!set->is_seen) | |
923 | res = 1; | |
924 | else | |
925 | res = set->is_seen(set); | |
926 | spin_unlock(&sysctl_lock); | |
927 | return res; | |
928 | } | |
929 | ||
6fa67e70 | 930 | static int proc_sys_compare(const struct dentry *dentry, |
621e155a | 931 | unsigned int len, const char *str, const struct qstr *name) |
9043476f | 932 | { |
dfef6dcd | 933 | struct ctl_table_header *head; |
da53be12 LT |
934 | struct inode *inode; |
935 | ||
31e6b01f NP |
936 | /* Although proc doesn't have negative dentries, rcu-walk means |
937 | * that inode here can be NULL */ | |
dfef6dcd | 938 | /* AV: can it, indeed? */ |
2b0143b5 | 939 | inode = d_inode_rcu(dentry); |
31e6b01f | 940 | if (!inode) |
dfef6dcd | 941 | return 1; |
621e155a | 942 | if (name->len != len) |
9043476f | 943 | return 1; |
621e155a | 944 | if (memcmp(name->name, str, len)) |
9043476f | 945 | return 1; |
dfef6dcd AV |
946 | head = rcu_dereference(PROC_I(inode)->sysctl); |
947 | return !head || !sysctl_is_seen(head); | |
77b14db5 EB |
948 | } |
949 | ||
d72f71eb | 950 | static const struct dentry_operations proc_sys_dentry_operations = { |
77b14db5 | 951 | .d_revalidate = proc_sys_revalidate, |
9043476f AV |
952 | .d_delete = proc_sys_delete, |
953 | .d_compare = proc_sys_compare, | |
77b14db5 EB |
954 | }; |
955 | ||
0e47c99d EB |
956 | static struct ctl_dir *find_subdir(struct ctl_dir *dir, |
957 | const char *name, int namelen) | |
1f87f0b5 | 958 | { |
7ec66d06 EB |
959 | struct ctl_table_header *head; |
960 | struct ctl_table *entry; | |
1f87f0b5 | 961 | |
0e47c99d | 962 | entry = find_entry(&head, dir, name, namelen); |
7ec66d06 EB |
963 | if (!entry) |
964 | return ERR_PTR(-ENOENT); | |
51f72f4a EB |
965 | if (!S_ISDIR(entry->mode)) |
966 | return ERR_PTR(-ENOTDIR); | |
967 | return container_of(head, struct ctl_dir, header); | |
7ec66d06 EB |
968 | } |
969 | ||
970 | static struct ctl_dir *new_dir(struct ctl_table_set *set, | |
0e47c99d | 971 | const char *name, int namelen) |
7ec66d06 EB |
972 | { |
973 | struct ctl_table *table; | |
974 | struct ctl_dir *new; | |
ac13ac6f | 975 | struct ctl_node *node; |
7ec66d06 | 976 | char *new_name; |
1f87f0b5 | 977 | |
ac13ac6f EB |
978 | new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + |
979 | sizeof(struct ctl_table)*2 + namelen + 1, | |
980 | GFP_KERNEL); | |
7ec66d06 | 981 | if (!new) |
1f87f0b5 EB |
982 | return NULL; |
983 | ||
ac13ac6f EB |
984 | node = (struct ctl_node *)(new + 1); |
985 | table = (struct ctl_table *)(node + 1); | |
7ec66d06 EB |
986 | new_name = (char *)(table + 2); |
987 | memcpy(new_name, name, namelen); | |
7ec66d06 EB |
988 | table[0].procname = new_name; |
989 | table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; | |
ac13ac6f | 990 | init_header(&new->header, set->dir.header.root, set, node, table); |
7ec66d06 EB |
991 | |
992 | return new; | |
1f87f0b5 EB |
993 | } |
994 | ||
60f126d9 EB |
995 | /** |
996 | * get_subdir - find or create a subdir with the specified name. | |
997 | * @dir: Directory to create the subdirectory in | |
998 | * @name: The name of the subdirectory to find or create | |
999 | * @namelen: The length of name | |
1000 | * | |
1001 | * Takes a directory with an elevated reference count so we know that | |
1002 | * if we drop the lock the directory will not go away. Upon success | |
1003 | * the reference is moved from @dir to the returned subdirectory. | |
1004 | * Upon error an error code is returned and the reference on @dir is | |
1005 | * simply dropped. | |
1006 | */ | |
0e47c99d EB |
1007 | static struct ctl_dir *get_subdir(struct ctl_dir *dir, |
1008 | const char *name, int namelen) | |
1f87f0b5 | 1009 | { |
0e47c99d | 1010 | struct ctl_table_set *set = dir->header.set; |
7ec66d06 | 1011 | struct ctl_dir *subdir, *new = NULL; |
0eb97f38 | 1012 | int err; |
1f87f0b5 | 1013 | |
7ec66d06 | 1014 | spin_lock(&sysctl_lock); |
0e47c99d | 1015 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
1016 | if (!IS_ERR(subdir)) |
1017 | goto found; | |
1018 | if (PTR_ERR(subdir) != -ENOENT) | |
1019 | goto failed; | |
1020 | ||
1021 | spin_unlock(&sysctl_lock); | |
1022 | new = new_dir(set, name, namelen); | |
1023 | spin_lock(&sysctl_lock); | |
1024 | subdir = ERR_PTR(-ENOMEM); | |
1025 | if (!new) | |
1026 | goto failed; | |
1027 | ||
60f126d9 | 1028 | /* Was the subdir added while we dropped the lock? */ |
0e47c99d | 1029 | subdir = find_subdir(dir, name, namelen); |
7ec66d06 EB |
1030 | if (!IS_ERR(subdir)) |
1031 | goto found; | |
1032 | if (PTR_ERR(subdir) != -ENOENT) | |
1033 | goto failed; | |
1034 | ||
60f126d9 | 1035 | /* Nope. Use the our freshly made directory entry. */ |
0eb97f38 EB |
1036 | err = insert_header(dir, &new->header); |
1037 | subdir = ERR_PTR(err); | |
1038 | if (err) | |
0e47c99d | 1039 | goto failed; |
7ec66d06 EB |
1040 | subdir = new; |
1041 | found: | |
1042 | subdir->header.nreg++; | |
1043 | failed: | |
a1c83681 | 1044 | if (IS_ERR(subdir)) { |
87ebdc00 | 1045 | pr_err("sysctl could not get directory: "); |
6980128f | 1046 | sysctl_print_dir(dir); |
153ee1c4 GU |
1047 | pr_cont("%*.*s %ld\n", namelen, namelen, name, |
1048 | PTR_ERR(subdir)); | |
1f87f0b5 | 1049 | } |
7ec66d06 EB |
1050 | drop_sysctl_table(&dir->header); |
1051 | if (new) | |
1052 | drop_sysctl_table(&new->header); | |
1053 | spin_unlock(&sysctl_lock); | |
1054 | return subdir; | |
1f87f0b5 EB |
1055 | } |
1056 | ||
0e47c99d EB |
1057 | static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) |
1058 | { | |
1059 | struct ctl_dir *parent; | |
1060 | const char *procname; | |
1061 | if (!dir->header.parent) | |
1062 | return &set->dir; | |
1063 | parent = xlate_dir(set, dir->header.parent); | |
1064 | if (IS_ERR(parent)) | |
1065 | return parent; | |
1066 | procname = dir->header.ctl_table[0].procname; | |
1067 | return find_subdir(parent, procname, strlen(procname)); | |
1068 | } | |
1069 | ||
1070 | static int sysctl_follow_link(struct ctl_table_header **phead, | |
13bcc6a2 | 1071 | struct ctl_table **pentry) |
0e47c99d EB |
1072 | { |
1073 | struct ctl_table_header *head; | |
1074 | struct ctl_table_root *root; | |
1075 | struct ctl_table_set *set; | |
1076 | struct ctl_table *entry; | |
1077 | struct ctl_dir *dir; | |
1078 | int ret; | |
1079 | ||
0e47c99d EB |
1080 | spin_lock(&sysctl_lock); |
1081 | root = (*pentry)->data; | |
13bcc6a2 | 1082 | set = lookup_header_set(root); |
0e47c99d EB |
1083 | dir = xlate_dir(set, (*phead)->parent); |
1084 | if (IS_ERR(dir)) | |
1085 | ret = PTR_ERR(dir); | |
1086 | else { | |
1087 | const char *procname = (*pentry)->procname; | |
1088 | head = NULL; | |
1089 | entry = find_entry(&head, dir, procname, strlen(procname)); | |
1090 | ret = -ENOENT; | |
1091 | if (entry && use_table(head)) { | |
1092 | unuse_table(*phead); | |
1093 | *phead = head; | |
1094 | *pentry = entry; | |
1095 | ret = 0; | |
1096 | } | |
1097 | } | |
1098 | ||
1099 | spin_unlock(&sysctl_lock); | |
1100 | return ret; | |
1101 | } | |
1102 | ||
7c60c48f | 1103 | static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) |
1f87f0b5 | 1104 | { |
7c60c48f EB |
1105 | struct va_format vaf; |
1106 | va_list args; | |
1f87f0b5 | 1107 | |
7c60c48f EB |
1108 | va_start(args, fmt); |
1109 | vaf.fmt = fmt; | |
1110 | vaf.va = &args; | |
1111 | ||
87ebdc00 AM |
1112 | pr_err("sysctl table check failed: %s/%s %pV\n", |
1113 | path, table->procname, &vaf); | |
1f87f0b5 | 1114 | |
7c60c48f EB |
1115 | va_end(args); |
1116 | return -EINVAL; | |
1f87f0b5 EB |
1117 | } |
1118 | ||
4f2fec00 LR |
1119 | static int sysctl_check_table_array(const char *path, struct ctl_table *table) |
1120 | { | |
1121 | int err = 0; | |
1122 | ||
61d9b56a LR |
1123 | if ((table->proc_handler == proc_douintvec) || |
1124 | (table->proc_handler == proc_douintvec_minmax)) { | |
4f2fec00 | 1125 | if (table->maxlen != sizeof(unsigned int)) |
64a11f3d | 1126 | err |= sysctl_err(path, table, "array not allowed"); |
4f2fec00 LR |
1127 | } |
1128 | ||
cb944413 ED |
1129 | if (table->proc_handler == proc_dou8vec_minmax) { |
1130 | if (table->maxlen != sizeof(u8)) | |
1131 | err |= sysctl_err(path, table, "array not allowed"); | |
1132 | } | |
1133 | ||
4f2fec00 LR |
1134 | return err; |
1135 | } | |
1136 | ||
7c60c48f | 1137 | static int sysctl_check_table(const char *path, struct ctl_table *table) |
1f87f0b5 | 1138 | { |
cb55f27a | 1139 | struct ctl_table *entry; |
7c60c48f | 1140 | int err = 0; |
cb55f27a MT |
1141 | list_for_each_table_entry(entry, table) { |
1142 | if (entry->child) | |
1143 | err |= sysctl_err(path, entry, "Not a file"); | |
1144 | ||
1145 | if ((entry->proc_handler == proc_dostring) || | |
1146 | (entry->proc_handler == proc_dointvec) || | |
1147 | (entry->proc_handler == proc_douintvec) || | |
1148 | (entry->proc_handler == proc_douintvec_minmax) || | |
1149 | (entry->proc_handler == proc_dointvec_minmax) || | |
1150 | (entry->proc_handler == proc_dou8vec_minmax) || | |
1151 | (entry->proc_handler == proc_dointvec_jiffies) || | |
1152 | (entry->proc_handler == proc_dointvec_userhz_jiffies) || | |
1153 | (entry->proc_handler == proc_dointvec_ms_jiffies) || | |
1154 | (entry->proc_handler == proc_doulongvec_minmax) || | |
1155 | (entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { | |
1156 | if (!entry->data) | |
1157 | err |= sysctl_err(path, entry, "No data"); | |
1158 | if (!entry->maxlen) | |
1159 | err |= sysctl_err(path, entry, "No maxlen"); | |
4f2fec00 | 1160 | else |
cb55f27a | 1161 | err |= sysctl_check_table_array(path, entry); |
7c60c48f | 1162 | } |
cb55f27a MT |
1163 | if (!entry->proc_handler) |
1164 | err |= sysctl_err(path, entry, "No proc_handler"); | |
7c60c48f | 1165 | |
cb55f27a MT |
1166 | if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode) |
1167 | err |= sysctl_err(path, entry, "bogus .mode 0%o", | |
1168 | entry->mode); | |
1f87f0b5 | 1169 | } |
7c60c48f | 1170 | return err; |
1f87f0b5 | 1171 | } |
1f87f0b5 | 1172 | |
0e47c99d EB |
1173 | static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, |
1174 | struct ctl_table_root *link_root) | |
1175 | { | |
1176 | struct ctl_table *link_table, *entry, *link; | |
1177 | struct ctl_table_header *links; | |
ac13ac6f | 1178 | struct ctl_node *node; |
0e47c99d EB |
1179 | char *link_name; |
1180 | int nr_entries, name_bytes; | |
1181 | ||
1182 | name_bytes = 0; | |
1183 | nr_entries = 0; | |
cb55f27a | 1184 | list_for_each_table_entry(entry, table) { |
0e47c99d EB |
1185 | nr_entries++; |
1186 | name_bytes += strlen(entry->procname) + 1; | |
1187 | } | |
1188 | ||
1189 | links = kzalloc(sizeof(struct ctl_table_header) + | |
ac13ac6f | 1190 | sizeof(struct ctl_node)*nr_entries + |
0e47c99d EB |
1191 | sizeof(struct ctl_table)*(nr_entries + 1) + |
1192 | name_bytes, | |
1193 | GFP_KERNEL); | |
1194 | ||
1195 | if (!links) | |
1196 | return NULL; | |
1197 | ||
ac13ac6f EB |
1198 | node = (struct ctl_node *)(links + 1); |
1199 | link_table = (struct ctl_table *)(node + nr_entries); | |
0e47c99d | 1200 | link_name = (char *)&link_table[nr_entries + 1]; |
cb55f27a | 1201 | link = link_table; |
0e47c99d | 1202 | |
cb55f27a | 1203 | list_for_each_table_entry(entry, table) { |
0e47c99d EB |
1204 | int len = strlen(entry->procname) + 1; |
1205 | memcpy(link_name, entry->procname, len); | |
1206 | link->procname = link_name; | |
1207 | link->mode = S_IFLNK|S_IRWXUGO; | |
1208 | link->data = link_root; | |
1209 | link_name += len; | |
cb55f27a | 1210 | link++; |
0e47c99d | 1211 | } |
ac13ac6f | 1212 | init_header(links, dir->header.root, dir->header.set, node, link_table); |
0e47c99d EB |
1213 | links->nreg = nr_entries; |
1214 | ||
1215 | return links; | |
1216 | } | |
1217 | ||
1218 | static bool get_links(struct ctl_dir *dir, | |
1219 | struct ctl_table *table, struct ctl_table_root *link_root) | |
1220 | { | |
1221 | struct ctl_table_header *head; | |
1222 | struct ctl_table *entry, *link; | |
1223 | ||
1224 | /* Are there links available for every entry in table? */ | |
cb55f27a | 1225 | list_for_each_table_entry(entry, table) { |
0e47c99d EB |
1226 | const char *procname = entry->procname; |
1227 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1228 | if (!link) | |
1229 | return false; | |
1230 | if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) | |
1231 | continue; | |
1232 | if (S_ISLNK(link->mode) && (link->data == link_root)) | |
1233 | continue; | |
1234 | return false; | |
1235 | } | |
1236 | ||
1237 | /* The checks passed. Increase the registration count on the links */ | |
cb55f27a | 1238 | list_for_each_table_entry(entry, table) { |
0e47c99d EB |
1239 | const char *procname = entry->procname; |
1240 | link = find_entry(&head, dir, procname, strlen(procname)); | |
1241 | head->nreg++; | |
1242 | } | |
1243 | return true; | |
1244 | } | |
1245 | ||
1246 | static int insert_links(struct ctl_table_header *head) | |
1247 | { | |
1248 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1249 | struct ctl_dir *core_parent = NULL; | |
1250 | struct ctl_table_header *links; | |
1251 | int err; | |
1252 | ||
1253 | if (head->set == root_set) | |
1254 | return 0; | |
1255 | ||
1256 | core_parent = xlate_dir(root_set, head->parent); | |
1257 | if (IS_ERR(core_parent)) | |
1258 | return 0; | |
1259 | ||
1260 | if (get_links(core_parent, head->ctl_table, head->root)) | |
1261 | return 0; | |
1262 | ||
1263 | core_parent->header.nreg++; | |
1264 | spin_unlock(&sysctl_lock); | |
1265 | ||
1266 | links = new_links(core_parent, head->ctl_table, head->root); | |
1267 | ||
1268 | spin_lock(&sysctl_lock); | |
1269 | err = -ENOMEM; | |
1270 | if (!links) | |
1271 | goto out; | |
1272 | ||
1273 | err = 0; | |
1274 | if (get_links(core_parent, head->ctl_table, head->root)) { | |
1275 | kfree(links); | |
1276 | goto out; | |
1277 | } | |
1278 | ||
1279 | err = insert_header(core_parent, links); | |
1280 | if (err) | |
1281 | kfree(links); | |
1282 | out: | |
1283 | drop_sysctl_table(&core_parent->header); | |
1284 | return err; | |
1285 | } | |
1286 | ||
1f87f0b5 | 1287 | /** |
f728019b | 1288 | * __register_sysctl_table - register a leaf sysctl table |
60a47a2e | 1289 | * @set: Sysctl tree to register on |
1f87f0b5 EB |
1290 | * @path: The path to the directory the sysctl table is in. |
1291 | * @table: the top-level table structure | |
1292 | * | |
1293 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1294 | * array. A completely 0 filled entry terminates the table. | |
1295 | * | |
1296 | * The members of the &struct ctl_table structure are used as follows: | |
1297 | * | |
1298 | * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not | |
1299 | * enter a sysctl file | |
1300 | * | |
1301 | * data - a pointer to data for use by proc_handler | |
1302 | * | |
1303 | * maxlen - the maximum size in bytes of the data | |
1304 | * | |
f728019b | 1305 | * mode - the file permissions for the /proc/sys file |
1f87f0b5 | 1306 | * |
f728019b | 1307 | * child - must be %NULL. |
1f87f0b5 EB |
1308 | * |
1309 | * proc_handler - the text handler routine (described below) | |
1310 | * | |
1f87f0b5 EB |
1311 | * extra1, extra2 - extra pointers usable by the proc handler routines |
1312 | * | |
1313 | * Leaf nodes in the sysctl tree will be represented by a single file | |
1314 | * under /proc; non-leaf nodes will be represented by directories. | |
1315 | * | |
f728019b EB |
1316 | * There must be a proc_handler routine for any terminal nodes. |
1317 | * Several default handlers are available to cover common cases - | |
1f87f0b5 EB |
1318 | * |
1319 | * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), | |
1320 | * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), | |
1321 | * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() | |
1322 | * | |
1323 | * It is the handler's job to read the input buffer from user memory | |
1324 | * and process it. The handler should return 0 on success. | |
1325 | * | |
1326 | * This routine returns %NULL on a failure to register, and a pointer | |
1327 | * to the table header on success. | |
1328 | */ | |
6e9d5164 | 1329 | struct ctl_table_header *__register_sysctl_table( |
60a47a2e | 1330 | struct ctl_table_set *set, |
6e9d5164 | 1331 | const char *path, struct ctl_table *table) |
1f87f0b5 | 1332 | { |
60a47a2e | 1333 | struct ctl_table_root *root = set->dir.header.root; |
1f87f0b5 | 1334 | struct ctl_table_header *header; |
6e9d5164 | 1335 | const char *name, *nextname; |
7ec66d06 | 1336 | struct ctl_dir *dir; |
ac13ac6f EB |
1337 | struct ctl_table *entry; |
1338 | struct ctl_node *node; | |
1339 | int nr_entries = 0; | |
1340 | ||
cb55f27a | 1341 | list_for_each_table_entry(entry, table) |
ac13ac6f | 1342 | nr_entries++; |
1f87f0b5 | 1343 | |
ac13ac6f | 1344 | header = kzalloc(sizeof(struct ctl_table_header) + |
425b9c7f | 1345 | sizeof(struct ctl_node)*nr_entries, GFP_KERNEL_ACCOUNT); |
1f87f0b5 EB |
1346 | if (!header) |
1347 | return NULL; | |
1348 | ||
ac13ac6f EB |
1349 | node = (struct ctl_node *)(header + 1); |
1350 | init_header(header, root, set, node, table); | |
7ec66d06 EB |
1351 | if (sysctl_check_table(path, table)) |
1352 | goto fail; | |
1353 | ||
1354 | spin_lock(&sysctl_lock); | |
0e47c99d | 1355 | dir = &set->dir; |
60f126d9 | 1356 | /* Reference moved down the diretory tree get_subdir */ |
7ec66d06 EB |
1357 | dir->header.nreg++; |
1358 | spin_unlock(&sysctl_lock); | |
1f87f0b5 | 1359 | |
7ec66d06 | 1360 | /* Find the directory for the ctl_table */ |
6e9d5164 EB |
1361 | for (name = path; name; name = nextname) { |
1362 | int namelen; | |
1363 | nextname = strchr(name, '/'); | |
1364 | if (nextname) { | |
1365 | namelen = nextname - name; | |
1366 | nextname++; | |
1367 | } else { | |
1368 | namelen = strlen(name); | |
1369 | } | |
1370 | if (namelen == 0) | |
1371 | continue; | |
1f87f0b5 | 1372 | |
0e47c99d | 1373 | dir = get_subdir(dir, name, namelen); |
7ec66d06 EB |
1374 | if (IS_ERR(dir)) |
1375 | goto fail; | |
1f87f0b5 | 1376 | } |
0e47c99d | 1377 | |
1f87f0b5 | 1378 | spin_lock(&sysctl_lock); |
0e47c99d | 1379 | if (insert_header(dir, header)) |
7ec66d06 | 1380 | goto fail_put_dir_locked; |
0e47c99d | 1381 | |
7ec66d06 | 1382 | drop_sysctl_table(&dir->header); |
1f87f0b5 EB |
1383 | spin_unlock(&sysctl_lock); |
1384 | ||
1385 | return header; | |
0e47c99d | 1386 | |
7ec66d06 EB |
1387 | fail_put_dir_locked: |
1388 | drop_sysctl_table(&dir->header); | |
7c60c48f EB |
1389 | spin_unlock(&sysctl_lock); |
1390 | fail: | |
1391 | kfree(header); | |
1392 | dump_stack(); | |
1393 | return NULL; | |
1f87f0b5 EB |
1394 | } |
1395 | ||
fea478d4 EB |
1396 | /** |
1397 | * register_sysctl - register a sysctl table | |
1398 | * @path: The path to the directory the sysctl table is in. | |
1399 | * @table: the table structure | |
1400 | * | |
1401 | * Register a sysctl table. @table should be a filled in ctl_table | |
1402 | * array. A completely 0 filled entry terminates the table. | |
1403 | * | |
1404 | * See __register_sysctl_table for more details. | |
1405 | */ | |
1406 | struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) | |
1407 | { | |
1408 | return __register_sysctl_table(&sysctl_table_root.default_set, | |
1409 | path, table); | |
1410 | } | |
1411 | EXPORT_SYMBOL(register_sysctl); | |
1412 | ||
3ddd9a80 XN |
1413 | /** |
1414 | * __register_sysctl_init() - register sysctl table to path | |
1415 | * @path: path name for sysctl base | |
1416 | * @table: This is the sysctl table that needs to be registered to the path | |
1417 | * @table_name: The name of sysctl table, only used for log printing when | |
1418 | * registration fails | |
1419 | * | |
1420 | * The sysctl interface is used by userspace to query or modify at runtime | |
1421 | * a predefined value set on a variable. These variables however have default | |
1422 | * values pre-set. Code which depends on these variables will always work even | |
1423 | * if register_sysctl() fails. If register_sysctl() fails you'd just loose the | |
1424 | * ability to query or modify the sysctls dynamically at run time. Chances of | |
1425 | * register_sysctl() failing on init are extremely low, and so for both reasons | |
1426 | * this function does not return any error as it is used by initialization code. | |
1427 | * | |
1428 | * Context: Can only be called after your respective sysctl base path has been | |
1429 | * registered. So for instance, most base directories are registered early on | |
1430 | * init before init levels are processed through proc_sys_init() and | |
d8c0418a | 1431 | * sysctl_init_bases(). |
3ddd9a80 XN |
1432 | */ |
1433 | void __init __register_sysctl_init(const char *path, struct ctl_table *table, | |
1434 | const char *table_name) | |
1435 | { | |
1436 | struct ctl_table_header *hdr = register_sysctl(path, table); | |
1437 | ||
1438 | if (unlikely(!hdr)) { | |
1439 | pr_err("failed when register_sysctl %s to %s\n", table_name, path); | |
1440 | return; | |
1441 | } | |
1442 | kmemleak_not_leak(hdr); | |
1443 | } | |
1444 | ||
6e9d5164 EB |
1445 | static char *append_path(const char *path, char *pos, const char *name) |
1446 | { | |
1447 | int namelen; | |
1448 | namelen = strlen(name); | |
1449 | if (((pos - path) + namelen + 2) >= PATH_MAX) | |
1450 | return NULL; | |
1451 | memcpy(pos, name, namelen); | |
1452 | pos[namelen] = '/'; | |
1453 | pos[namelen + 1] = '\0'; | |
1454 | pos += namelen + 1; | |
1455 | return pos; | |
1456 | } | |
1457 | ||
f728019b EB |
1458 | static int count_subheaders(struct ctl_table *table) |
1459 | { | |
1460 | int has_files = 0; | |
1461 | int nr_subheaders = 0; | |
1462 | struct ctl_table *entry; | |
1463 | ||
1464 | /* special case: no directory and empty directory */ | |
1465 | if (!table || !table->procname) | |
1466 | return 1; | |
1467 | ||
cb55f27a | 1468 | list_for_each_table_entry(entry, table) { |
f728019b EB |
1469 | if (entry->child) |
1470 | nr_subheaders += count_subheaders(entry->child); | |
1471 | else | |
1472 | has_files = 1; | |
1473 | } | |
1474 | return nr_subheaders + has_files; | |
1475 | } | |
1476 | ||
1477 | static int register_leaf_sysctl_tables(const char *path, char *pos, | |
60a47a2e | 1478 | struct ctl_table_header ***subheader, struct ctl_table_set *set, |
f728019b EB |
1479 | struct ctl_table *table) |
1480 | { | |
1481 | struct ctl_table *ctl_table_arg = NULL; | |
1482 | struct ctl_table *entry, *files; | |
1483 | int nr_files = 0; | |
1484 | int nr_dirs = 0; | |
1485 | int err = -ENOMEM; | |
1486 | ||
cb55f27a | 1487 | list_for_each_table_entry(entry, table) { |
f728019b EB |
1488 | if (entry->child) |
1489 | nr_dirs++; | |
1490 | else | |
1491 | nr_files++; | |
1492 | } | |
1493 | ||
1494 | files = table; | |
1495 | /* If there are mixed files and directories we need a new table */ | |
1496 | if (nr_dirs && nr_files) { | |
1497 | struct ctl_table *new; | |
6396bb22 | 1498 | files = kcalloc(nr_files + 1, sizeof(struct ctl_table), |
f728019b EB |
1499 | GFP_KERNEL); |
1500 | if (!files) | |
1501 | goto out; | |
1502 | ||
1503 | ctl_table_arg = files; | |
cb55f27a MT |
1504 | new = files; |
1505 | ||
1506 | list_for_each_table_entry(entry, table) { | |
f728019b EB |
1507 | if (entry->child) |
1508 | continue; | |
1509 | *new = *entry; | |
1510 | new++; | |
1511 | } | |
1512 | } | |
1513 | ||
1514 | /* Register everything except a directory full of subdirectories */ | |
1515 | if (nr_files || !nr_dirs) { | |
1516 | struct ctl_table_header *header; | |
60a47a2e | 1517 | header = __register_sysctl_table(set, path, files); |
f728019b EB |
1518 | if (!header) { |
1519 | kfree(ctl_table_arg); | |
1520 | goto out; | |
1521 | } | |
1522 | ||
1523 | /* Remember if we need to free the file table */ | |
1524 | header->ctl_table_arg = ctl_table_arg; | |
1525 | **subheader = header; | |
1526 | (*subheader)++; | |
1527 | } | |
1528 | ||
1529 | /* Recurse into the subdirectories. */ | |
cb55f27a | 1530 | list_for_each_table_entry(entry, table) { |
f728019b EB |
1531 | char *child_pos; |
1532 | ||
1533 | if (!entry->child) | |
1534 | continue; | |
1535 | ||
1536 | err = -ENAMETOOLONG; | |
1537 | child_pos = append_path(path, pos, entry->procname); | |
1538 | if (!child_pos) | |
1539 | goto out; | |
1540 | ||
1541 | err = register_leaf_sysctl_tables(path, child_pos, subheader, | |
60a47a2e | 1542 | set, entry->child); |
f728019b EB |
1543 | pos[0] = '\0'; |
1544 | if (err) | |
1545 | goto out; | |
1546 | } | |
1547 | err = 0; | |
1548 | out: | |
1549 | /* On failure our caller will unregister all registered subheaders */ | |
1550 | return err; | |
1551 | } | |
1552 | ||
6e9d5164 EB |
1553 | /** |
1554 | * __register_sysctl_paths - register a sysctl table hierarchy | |
60a47a2e | 1555 | * @set: Sysctl tree to register on |
6e9d5164 EB |
1556 | * @path: The path to the directory the sysctl table is in. |
1557 | * @table: the top-level table structure | |
1558 | * | |
1559 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1560 | * array. A completely 0 filled entry terminates the table. | |
1561 | * | |
1562 | * See __register_sysctl_table for more details. | |
1563 | */ | |
1564 | struct ctl_table_header *__register_sysctl_paths( | |
60a47a2e | 1565 | struct ctl_table_set *set, |
6e9d5164 EB |
1566 | const struct ctl_path *path, struct ctl_table *table) |
1567 | { | |
ec6a5266 | 1568 | struct ctl_table *ctl_table_arg = table; |
f728019b EB |
1569 | int nr_subheaders = count_subheaders(table); |
1570 | struct ctl_table_header *header = NULL, **subheaders, **subheader; | |
6e9d5164 EB |
1571 | const struct ctl_path *component; |
1572 | char *new_path, *pos; | |
1573 | ||
1574 | pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); | |
1575 | if (!new_path) | |
1576 | return NULL; | |
1577 | ||
1578 | pos[0] = '\0'; | |
1579 | for (component = path; component->procname; component++) { | |
1580 | pos = append_path(new_path, pos, component->procname); | |
1581 | if (!pos) | |
1582 | goto out; | |
1583 | } | |
ec6a5266 EB |
1584 | while (table->procname && table->child && !table[1].procname) { |
1585 | pos = append_path(new_path, pos, table->procname); | |
1586 | if (!pos) | |
1587 | goto out; | |
1588 | table = table->child; | |
1589 | } | |
f728019b | 1590 | if (nr_subheaders == 1) { |
60a47a2e | 1591 | header = __register_sysctl_table(set, new_path, table); |
f728019b EB |
1592 | if (header) |
1593 | header->ctl_table_arg = ctl_table_arg; | |
1594 | } else { | |
1595 | header = kzalloc(sizeof(*header) + | |
1596 | sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); | |
1597 | if (!header) | |
1598 | goto out; | |
1599 | ||
1600 | subheaders = (struct ctl_table_header **) (header + 1); | |
1601 | subheader = subheaders; | |
ec6a5266 | 1602 | header->ctl_table_arg = ctl_table_arg; |
f728019b EB |
1603 | |
1604 | if (register_leaf_sysctl_tables(new_path, pos, &subheader, | |
60a47a2e | 1605 | set, table)) |
f728019b EB |
1606 | goto err_register_leaves; |
1607 | } | |
1608 | ||
6e9d5164 EB |
1609 | out: |
1610 | kfree(new_path); | |
1611 | return header; | |
f728019b EB |
1612 | |
1613 | err_register_leaves: | |
1614 | while (subheader > subheaders) { | |
1615 | struct ctl_table_header *subh = *(--subheader); | |
1616 | struct ctl_table *table = subh->ctl_table_arg; | |
1617 | unregister_sysctl_table(subh); | |
1618 | kfree(table); | |
1619 | } | |
1620 | kfree(header); | |
1621 | header = NULL; | |
1622 | goto out; | |
6e9d5164 EB |
1623 | } |
1624 | ||
1f87f0b5 | 1625 | /** |
5b31a7df | 1626 | * register_sysctl_paths - register a sysctl table hierarchy |
1f87f0b5 EB |
1627 | * @path: The path to the directory the sysctl table is in. |
1628 | * @table: the top-level table structure | |
1629 | * | |
1630 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1631 | * array. A completely 0 filled entry terminates the table. | |
1632 | * | |
1633 | * See __register_sysctl_paths for more details. | |
1634 | */ | |
1635 | struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, | |
1636 | struct ctl_table *table) | |
1637 | { | |
60a47a2e | 1638 | return __register_sysctl_paths(&sysctl_table_root.default_set, |
1f87f0b5 EB |
1639 | path, table); |
1640 | } | |
1641 | EXPORT_SYMBOL(register_sysctl_paths); | |
1642 | ||
1643 | /** | |
1644 | * register_sysctl_table - register a sysctl table hierarchy | |
1645 | * @table: the top-level table structure | |
1646 | * | |
1647 | * Register a sysctl table hierarchy. @table should be a filled in ctl_table | |
1648 | * array. A completely 0 filled entry terminates the table. | |
1649 | * | |
1650 | * See register_sysctl_paths for more details. | |
1651 | */ | |
1652 | struct ctl_table_header *register_sysctl_table(struct ctl_table *table) | |
1653 | { | |
1654 | static const struct ctl_path null_path[] = { {} }; | |
1655 | ||
1656 | return register_sysctl_paths(null_path, table); | |
1657 | } | |
1658 | EXPORT_SYMBOL(register_sysctl_table); | |
1659 | ||
51cb8dfc LC |
1660 | int __register_sysctl_base(struct ctl_table *base_table) |
1661 | { | |
1662 | struct ctl_table_header *hdr; | |
1663 | ||
1664 | hdr = register_sysctl_table(base_table); | |
1665 | kmemleak_not_leak(hdr); | |
1666 | return 0; | |
1667 | } | |
1668 | ||
0e47c99d EB |
1669 | static void put_links(struct ctl_table_header *header) |
1670 | { | |
1671 | struct ctl_table_set *root_set = &sysctl_table_root.default_set; | |
1672 | struct ctl_table_root *root = header->root; | |
1673 | struct ctl_dir *parent = header->parent; | |
1674 | struct ctl_dir *core_parent; | |
1675 | struct ctl_table *entry; | |
1676 | ||
1677 | if (header->set == root_set) | |
1678 | return; | |
1679 | ||
1680 | core_parent = xlate_dir(root_set, parent); | |
1681 | if (IS_ERR(core_parent)) | |
1682 | return; | |
1683 | ||
cb55f27a | 1684 | list_for_each_table_entry(entry, header->ctl_table) { |
0e47c99d EB |
1685 | struct ctl_table_header *link_head; |
1686 | struct ctl_table *link; | |
1687 | const char *name = entry->procname; | |
1688 | ||
1689 | link = find_entry(&link_head, core_parent, name, strlen(name)); | |
1690 | if (link && | |
1691 | ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || | |
1692 | (S_ISLNK(link->mode) && (link->data == root)))) { | |
1693 | drop_sysctl_table(link_head); | |
1694 | } | |
1695 | else { | |
87ebdc00 | 1696 | pr_err("sysctl link missing during unregister: "); |
0e47c99d | 1697 | sysctl_print_dir(parent); |
153ee1c4 | 1698 | pr_cont("%s\n", name); |
0e47c99d EB |
1699 | } |
1700 | } | |
1701 | } | |
1702 | ||
938aaa4f EB |
1703 | static void drop_sysctl_table(struct ctl_table_header *header) |
1704 | { | |
7ec66d06 EB |
1705 | struct ctl_dir *parent = header->parent; |
1706 | ||
938aaa4f EB |
1707 | if (--header->nreg) |
1708 | return; | |
1709 | ||
89189557 | 1710 | if (parent) { |
23da9588 | 1711 | put_links(header); |
89189557 Y |
1712 | start_unregistering(header); |
1713 | } | |
1714 | ||
938aaa4f EB |
1715 | if (!--header->count) |
1716 | kfree_rcu(header, rcu); | |
7ec66d06 EB |
1717 | |
1718 | if (parent) | |
1719 | drop_sysctl_table(&parent->header); | |
938aaa4f EB |
1720 | } |
1721 | ||
1f87f0b5 EB |
1722 | /** |
1723 | * unregister_sysctl_table - unregister a sysctl table hierarchy | |
1724 | * @header: the header returned from register_sysctl_table | |
1725 | * | |
1726 | * Unregisters the sysctl table and all children. proc entries may not | |
1727 | * actually be removed until they are no longer used by anyone. | |
1728 | */ | |
1729 | void unregister_sysctl_table(struct ctl_table_header * header) | |
1730 | { | |
f728019b | 1731 | int nr_subheaders; |
1f87f0b5 EB |
1732 | might_sleep(); |
1733 | ||
1734 | if (header == NULL) | |
1735 | return; | |
1736 | ||
f728019b EB |
1737 | nr_subheaders = count_subheaders(header->ctl_table_arg); |
1738 | if (unlikely(nr_subheaders > 1)) { | |
1739 | struct ctl_table_header **subheaders; | |
1740 | int i; | |
1741 | ||
1742 | subheaders = (struct ctl_table_header **)(header + 1); | |
1743 | for (i = nr_subheaders -1; i >= 0; i--) { | |
1744 | struct ctl_table_header *subh = subheaders[i]; | |
1745 | struct ctl_table *table = subh->ctl_table_arg; | |
1746 | unregister_sysctl_table(subh); | |
1747 | kfree(table); | |
1748 | } | |
1749 | kfree(header); | |
1750 | return; | |
1751 | } | |
1752 | ||
1f87f0b5 | 1753 | spin_lock(&sysctl_lock); |
938aaa4f | 1754 | drop_sysctl_table(header); |
1f87f0b5 EB |
1755 | spin_unlock(&sysctl_lock); |
1756 | } | |
1757 | EXPORT_SYMBOL(unregister_sysctl_table); | |
1758 | ||
0e47c99d | 1759 | void setup_sysctl_set(struct ctl_table_set *set, |
9eb47c26 | 1760 | struct ctl_table_root *root, |
1f87f0b5 EB |
1761 | int (*is_seen)(struct ctl_table_set *)) |
1762 | { | |
1347440d | 1763 | memset(set, 0, sizeof(*set)); |
0e47c99d | 1764 | set->is_seen = is_seen; |
ac13ac6f | 1765 | init_header(&set->dir.header, root, set, NULL, root_table); |
1f87f0b5 EB |
1766 | } |
1767 | ||
97324cd8 EB |
1768 | void retire_sysctl_set(struct ctl_table_set *set) |
1769 | { | |
ac13ac6f | 1770 | WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); |
97324cd8 | 1771 | } |
1f87f0b5 | 1772 | |
1e0edd3f | 1773 | int __init proc_sys_init(void) |
77b14db5 | 1774 | { |
e1675231 AD |
1775 | struct proc_dir_entry *proc_sys_root; |
1776 | ||
77b14db5 | 1777 | proc_sys_root = proc_mkdir("sys", NULL); |
9043476f | 1778 | proc_sys_root->proc_iops = &proc_sys_dir_operations; |
d56c0d45 | 1779 | proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; |
77b14db5 | 1780 | proc_sys_root->nlink = 0; |
de4e83bd | 1781 | |
d8c0418a | 1782 | return sysctl_init_bases(); |
77b14db5 | 1783 | } |
3db978d4 | 1784 | |
0a477e1a VB |
1785 | struct sysctl_alias { |
1786 | const char *kernel_param; | |
1787 | const char *sysctl_param; | |
1788 | }; | |
1789 | ||
1790 | /* | |
1791 | * Historically some settings had both sysctl and a command line parameter. | |
1792 | * With the generic sysctl. parameter support, we can handle them at a single | |
1793 | * place and only keep the historical name for compatibility. This is not meant | |
1794 | * to add brand new aliases. When adding existing aliases, consider whether | |
1795 | * the possibly different moment of changing the value (e.g. from early_param | |
1796 | * to the moment do_sysctl_args() is called) is an issue for the specific | |
1797 | * parameter. | |
1798 | */ | |
1799 | static const struct sysctl_alias sysctl_aliases[] = { | |
f117955a GP |
1800 | {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, |
1801 | {"hung_task_panic", "kernel.hung_task_panic" }, | |
1802 | {"numa_zonelist_order", "vm.numa_zonelist_order" }, | |
1803 | {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, | |
1804 | {"softlockup_panic", "kernel.softlockup_panic" }, | |
0a477e1a VB |
1805 | { } |
1806 | }; | |
1807 | ||
1808 | static const char *sysctl_find_alias(char *param) | |
1809 | { | |
1810 | const struct sysctl_alias *alias; | |
1811 | ||
1812 | for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { | |
1813 | if (strcmp(alias->kernel_param, param) == 0) | |
1814 | return alias->sysctl_param; | |
1815 | } | |
1816 | ||
1817 | return NULL; | |
1818 | } | |
1819 | ||
3db978d4 VB |
1820 | /* Set sysctl value passed on kernel command line. */ |
1821 | static int process_sysctl_arg(char *param, char *val, | |
1822 | const char *unused, void *arg) | |
1823 | { | |
1824 | char *path; | |
1825 | struct vfsmount **proc_mnt = arg; | |
1826 | struct file_system_type *proc_fs_type; | |
1827 | struct file *file; | |
1828 | int len; | |
1829 | int err; | |
1830 | loff_t pos = 0; | |
1831 | ssize_t wret; | |
1832 | ||
0a477e1a VB |
1833 | if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { |
1834 | param += sizeof("sysctl") - 1; | |
3db978d4 | 1835 | |
0a477e1a VB |
1836 | if (param[0] != '/' && param[0] != '.') |
1837 | return 0; | |
3db978d4 | 1838 | |
0a477e1a VB |
1839 | param++; |
1840 | } else { | |
1841 | param = (char *) sysctl_find_alias(param); | |
1842 | if (!param) | |
1843 | return 0; | |
1844 | } | |
3db978d4 | 1845 | |
697edcb0 XN |
1846 | if (!val) |
1847 | return -EINVAL; | |
1848 | len = strlen(val); | |
1849 | if (len == 0) | |
1850 | return -EINVAL; | |
1851 | ||
3db978d4 VB |
1852 | /* |
1853 | * To set sysctl options, we use a temporary mount of proc, look up the | |
1854 | * respective sys/ file and write to it. To avoid mounting it when no | |
1855 | * options were given, we mount it only when the first sysctl option is | |
1856 | * found. Why not a persistent mount? There are problems with a | |
1857 | * persistent mount of proc in that it forces userspace not to use any | |
1858 | * proc mount options. | |
1859 | */ | |
1860 | if (!*proc_mnt) { | |
1861 | proc_fs_type = get_fs_type("proc"); | |
1862 | if (!proc_fs_type) { | |
1863 | pr_err("Failed to find procfs to set sysctl from command line\n"); | |
1864 | return 0; | |
1865 | } | |
1866 | *proc_mnt = kern_mount(proc_fs_type); | |
1867 | put_filesystem(proc_fs_type); | |
1868 | if (IS_ERR(*proc_mnt)) { | |
1869 | pr_err("Failed to mount procfs to set sysctl from command line\n"); | |
1870 | return 0; | |
1871 | } | |
1872 | } | |
1873 | ||
1874 | path = kasprintf(GFP_KERNEL, "sys/%s", param); | |
1875 | if (!path) | |
1876 | panic("%s: Failed to allocate path for %s\n", __func__, param); | |
1877 | strreplace(path, '.', '/'); | |
1878 | ||
ffb37ca3 | 1879 | file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); |
3db978d4 VB |
1880 | if (IS_ERR(file)) { |
1881 | err = PTR_ERR(file); | |
1882 | if (err == -ENOENT) | |
1883 | pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", | |
1884 | param, val); | |
1885 | else if (err == -EACCES) | |
1886 | pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", | |
1887 | param, val); | |
1888 | else | |
1889 | pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", | |
1890 | file, param, val); | |
1891 | goto out; | |
1892 | } | |
3db978d4 VB |
1893 | wret = kernel_write(file, val, len, &pos); |
1894 | if (wret < 0) { | |
1895 | err = wret; | |
1896 | if (err == -EINVAL) | |
1897 | pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", | |
1898 | param, val); | |
1899 | else | |
1900 | pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", | |
1901 | ERR_PTR(err), param, val); | |
1902 | } else if (wret != len) { | |
1903 | pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", | |
1904 | wret, len, path, param, val); | |
1905 | } | |
1906 | ||
1907 | err = filp_close(file, NULL); | |
1908 | if (err) | |
1909 | pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", | |
1910 | ERR_PTR(err), param, val); | |
1911 | out: | |
1912 | kfree(path); | |
1913 | return 0; | |
1914 | } | |
1915 | ||
1916 | void do_sysctl_args(void) | |
1917 | { | |
1918 | char *command_line; | |
1919 | struct vfsmount *proc_mnt = NULL; | |
1920 | ||
1921 | command_line = kstrdup(saved_command_line, GFP_KERNEL); | |
1922 | if (!command_line) | |
1923 | panic("%s: Failed to allocate copy of command line\n", __func__); | |
1924 | ||
1925 | parse_args("Setting sysctl args", command_line, | |
1926 | NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); | |
1927 | ||
1928 | if (proc_mnt) | |
1929 | kern_unmount(proc_mnt); | |
1930 | ||
1931 | kfree(command_line); | |
1932 | } |