1 //SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf-cgroup.h>
6 #include <linux/filter.h>
8 #include <linux/rbtree.h>
9 #include <linux/slab.h>
10 #include <uapi/linux/btf.h>
12 DEFINE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
14 #ifdef CONFIG_CGROUP_BPF
16 #include "../cgroup/cgroup-internal.h"
18 #define LOCAL_STORAGE_CREATE_FLAG_MASK \
19 (BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
21 struct bpf_cgroup_storage_map {
26 struct list_head list;
29 static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map)
31 return container_of(map, struct bpf_cgroup_storage_map, map);
34 static bool attach_type_isolated(const struct bpf_map *map)
36 return map->key_size == sizeof(struct bpf_cgroup_storage_key);
39 static int bpf_cgroup_storage_key_cmp(const struct bpf_cgroup_storage_map *map,
40 const void *_key1, const void *_key2)
42 if (attach_type_isolated(&map->map)) {
43 const struct bpf_cgroup_storage_key *key1 = _key1;
44 const struct bpf_cgroup_storage_key *key2 = _key2;
46 if (key1->cgroup_inode_id < key2->cgroup_inode_id)
48 else if (key1->cgroup_inode_id > key2->cgroup_inode_id)
50 else if (key1->attach_type < key2->attach_type)
52 else if (key1->attach_type > key2->attach_type)
55 const __u64 *cgroup_inode_id1 = _key1;
56 const __u64 *cgroup_inode_id2 = _key2;
58 if (*cgroup_inode_id1 < *cgroup_inode_id2)
60 else if (*cgroup_inode_id1 > *cgroup_inode_id2)
66 struct bpf_cgroup_storage *
67 cgroup_storage_lookup(struct bpf_cgroup_storage_map *map,
68 void *key, bool locked)
70 struct rb_root *root = &map->root;
74 spin_lock_bh(&map->lock);
78 struct bpf_cgroup_storage *storage;
80 storage = container_of(node, struct bpf_cgroup_storage, node);
82 switch (bpf_cgroup_storage_key_cmp(map, key, &storage->key)) {
87 node = node->rb_right;
91 spin_unlock_bh(&map->lock);
97 spin_unlock_bh(&map->lock);
102 static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map,
103 struct bpf_cgroup_storage *storage)
105 struct rb_root *root = &map->root;
106 struct rb_node **new = &(root->rb_node), *parent = NULL;
109 struct bpf_cgroup_storage *this;
111 this = container_of(*new, struct bpf_cgroup_storage, node);
114 switch (bpf_cgroup_storage_key_cmp(map, &storage->key, &this->key)) {
116 new = &((*new)->rb_left);
119 new = &((*new)->rb_right);
126 rb_link_node(&storage->node, parent, new);
127 rb_insert_color(&storage->node, root);
132 static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *key)
134 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
135 struct bpf_cgroup_storage *storage;
137 storage = cgroup_storage_lookup(map, key, false);
141 return &READ_ONCE(storage->buf)->data[0];
144 static int cgroup_storage_update_elem(struct bpf_map *map, void *key,
145 void *value, u64 flags)
147 struct bpf_cgroup_storage *storage;
148 struct bpf_storage_buffer *new;
150 if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST)))
153 if (unlikely((flags & BPF_F_LOCK) &&
154 !map_value_has_spin_lock(map)))
157 storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
162 if (flags & BPF_F_LOCK) {
163 copy_map_value_locked(map, storage->buf->data, value, false);
167 new = kmalloc_node(sizeof(struct bpf_storage_buffer) +
169 __GFP_ZERO | GFP_ATOMIC | __GFP_NOWARN,
174 memcpy(&new->data[0], value, map->value_size);
175 check_and_init_map_lock(map, new->data);
177 new = xchg(&storage->buf, new);
183 int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,
186 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
187 struct bpf_cgroup_storage *storage;
192 storage = cgroup_storage_lookup(map, key, false);
198 /* per_cpu areas are zero-filled and bpf programs can only
199 * access 'value_size' of them, so copying rounded areas
200 * will not leak any kernel data
202 size = round_up(_map->value_size, 8);
203 for_each_possible_cpu(cpu) {
204 bpf_long_memcpy(value + off,
205 per_cpu_ptr(storage->percpu_buf, cpu), size);
212 int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key,
213 void *value, u64 map_flags)
215 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
216 struct bpf_cgroup_storage *storage;
220 if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
224 storage = cgroup_storage_lookup(map, key, false);
230 /* the user space will provide round_up(value_size, 8) bytes that
231 * will be copied into per-cpu area. bpf programs can only access
232 * value_size of it. During lookup the same extra bytes will be
233 * returned or zeros which were zero-filled by percpu_alloc,
234 * so no kernel data leaks possible
236 size = round_up(_map->value_size, 8);
237 for_each_possible_cpu(cpu) {
238 bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu),
246 static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key,
249 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
250 struct bpf_cgroup_storage *storage;
252 spin_lock_bh(&map->lock);
254 if (list_empty(&map->list))
258 storage = cgroup_storage_lookup(map, key, true);
262 storage = list_next_entry(storage, list_map);
266 storage = list_first_entry(&map->list,
267 struct bpf_cgroup_storage, list_map);
270 spin_unlock_bh(&map->lock);
272 if (attach_type_isolated(&map->map)) {
273 struct bpf_cgroup_storage_key *next = _next_key;
274 *next = storage->key;
276 __u64 *next = _next_key;
277 *next = storage->key.cgroup_inode_id;
282 spin_unlock_bh(&map->lock);
286 static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
288 int numa_node = bpf_map_attr_numa_node(attr);
289 struct bpf_cgroup_storage_map *map;
290 struct bpf_map_memory mem;
293 if (attr->key_size != sizeof(struct bpf_cgroup_storage_key) &&
294 attr->key_size != sizeof(__u64))
295 return ERR_PTR(-EINVAL);
297 if (attr->value_size == 0)
298 return ERR_PTR(-EINVAL);
300 if (attr->value_size > PAGE_SIZE)
301 return ERR_PTR(-E2BIG);
303 if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
304 !bpf_map_flags_access_ok(attr->map_flags))
305 return ERR_PTR(-EINVAL);
307 if (attr->max_entries)
308 /* max_entries is not used and enforced to be 0 */
309 return ERR_PTR(-EINVAL);
311 ret = bpf_map_charge_init(&mem, sizeof(struct bpf_cgroup_storage_map));
315 map = kmalloc_node(sizeof(struct bpf_cgroup_storage_map),
316 __GFP_ZERO | GFP_USER, numa_node);
318 bpf_map_charge_finish(&mem);
319 return ERR_PTR(-ENOMEM);
322 bpf_map_charge_move(&map->map.memory, &mem);
324 /* copy mandatory map attributes */
325 bpf_map_init_from_attr(&map->map, attr);
327 spin_lock_init(&map->lock);
329 INIT_LIST_HEAD(&map->list);
334 static void cgroup_storage_map_free(struct bpf_map *_map)
336 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
337 struct list_head *storages = &map->list;
338 struct bpf_cgroup_storage *storage, *stmp;
340 mutex_lock(&cgroup_mutex);
342 list_for_each_entry_safe(storage, stmp, storages, list_map) {
343 bpf_cgroup_storage_unlink(storage);
344 bpf_cgroup_storage_free(storage);
347 mutex_unlock(&cgroup_mutex);
349 WARN_ON(!RB_EMPTY_ROOT(&map->root));
350 WARN_ON(!list_empty(&map->list));
355 static int cgroup_storage_delete_elem(struct bpf_map *map, void *key)
360 static int cgroup_storage_check_btf(const struct bpf_map *map,
361 const struct btf *btf,
362 const struct btf_type *key_type,
363 const struct btf_type *value_type)
365 if (attach_type_isolated(map)) {
366 struct btf_member *m;
369 /* Key is expected to be of struct bpf_cgroup_storage_key type,
371 * struct bpf_cgroup_storage_key {
372 * __u64 cgroup_inode_id;
378 * Key_type must be a structure with two fields.
380 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ||
381 BTF_INFO_VLEN(key_type->info) != 2)
385 * The first field must be a 64 bit integer at 0 offset.
387 m = (struct btf_member *)(key_type + 1);
388 size = sizeof_field(struct bpf_cgroup_storage_key, cgroup_inode_id);
389 if (!btf_member_is_reg_int(btf, key_type, m, 0, size))
393 * The second field must be a 32 bit integer at 64 bit offset.
396 offset = offsetof(struct bpf_cgroup_storage_key, attach_type);
397 size = sizeof_field(struct bpf_cgroup_storage_key, attach_type);
398 if (!btf_member_is_reg_int(btf, key_type, m, offset, size))
404 * Key is expected to be u64, which stores the cgroup_inode_id
407 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
410 int_data = *(u32 *)(key_type + 1);
411 if (BTF_INT_BITS(int_data) != 64 || BTF_INT_OFFSET(int_data))
418 static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *key,
421 enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
422 struct bpf_cgroup_storage *storage;
426 storage = cgroup_storage_lookup(map_to_storage(map), key, false);
432 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
433 stype = cgroup_storage_type(map);
434 if (stype == BPF_CGROUP_STORAGE_SHARED) {
436 btf_type_seq_show(map->btf, map->btf_value_type_id,
437 &READ_ONCE(storage->buf)->data[0], m);
440 seq_puts(m, ": {\n");
441 for_each_possible_cpu(cpu) {
442 seq_printf(m, "\tcpu%d: ", cpu);
443 btf_type_seq_show(map->btf, map->btf_value_type_id,
444 per_cpu_ptr(storage->percpu_buf, cpu),
453 static int cgroup_storage_map_btf_id;
454 const struct bpf_map_ops cgroup_storage_map_ops = {
455 .map_alloc = cgroup_storage_map_alloc,
456 .map_free = cgroup_storage_map_free,
457 .map_get_next_key = cgroup_storage_get_next_key,
458 .map_lookup_elem = cgroup_storage_lookup_elem,
459 .map_update_elem = cgroup_storage_update_elem,
460 .map_delete_elem = cgroup_storage_delete_elem,
461 .map_check_btf = cgroup_storage_check_btf,
462 .map_seq_show_elem = cgroup_storage_seq_show_elem,
463 .map_btf_name = "bpf_cgroup_storage_map",
464 .map_btf_id = &cgroup_storage_map_btf_id,
467 int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map)
469 enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
471 if (aux->cgroup_storage[stype] &&
472 aux->cgroup_storage[stype] != _map)
475 aux->cgroup_storage[stype] = _map;
479 static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages)
483 if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) {
484 size = sizeof(struct bpf_storage_buffer) + map->value_size;
485 *pages = round_up(sizeof(struct bpf_cgroup_storage) + size,
486 PAGE_SIZE) >> PAGE_SHIFT;
488 size = map->value_size;
489 *pages = round_up(round_up(size, 8) * num_possible_cpus(),
490 PAGE_SIZE) >> PAGE_SHIFT;
496 struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
497 enum bpf_cgroup_storage_type stype)
499 struct bpf_cgroup_storage *storage;
505 map = prog->aux->cgroup_storage[stype];
509 size = bpf_cgroup_storage_calculate_size(map, &pages);
511 if (bpf_map_charge_memlock(map, pages))
512 return ERR_PTR(-EPERM);
514 storage = kmalloc_node(sizeof(struct bpf_cgroup_storage),
515 __GFP_ZERO | GFP_USER, map->numa_node);
519 flags = __GFP_ZERO | GFP_USER;
521 if (stype == BPF_CGROUP_STORAGE_SHARED) {
522 storage->buf = kmalloc_node(size, flags, map->numa_node);
525 check_and_init_map_lock(map, storage->buf->data);
527 storage->percpu_buf = __alloc_percpu_gfp(size, 8, flags);
528 if (!storage->percpu_buf)
532 storage->map = (struct bpf_cgroup_storage_map *)map;
537 bpf_map_uncharge_memlock(map, pages);
539 return ERR_PTR(-ENOMEM);
542 static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
544 struct bpf_cgroup_storage *storage =
545 container_of(rcu, struct bpf_cgroup_storage, rcu);
551 static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
553 struct bpf_cgroup_storage *storage =
554 container_of(rcu, struct bpf_cgroup_storage, rcu);
556 free_percpu(storage->percpu_buf);
560 void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
562 enum bpf_cgroup_storage_type stype;
569 map = &storage->map->map;
571 bpf_cgroup_storage_calculate_size(map, &pages);
572 bpf_map_uncharge_memlock(map, pages);
574 stype = cgroup_storage_type(map);
575 if (stype == BPF_CGROUP_STORAGE_SHARED)
576 call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
578 call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);
581 void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
582 struct cgroup *cgroup,
583 enum bpf_attach_type type)
585 struct bpf_cgroup_storage_map *map;
590 storage->key.attach_type = type;
591 storage->key.cgroup_inode_id = cgroup_id(cgroup);
595 spin_lock_bh(&map->lock);
596 WARN_ON(cgroup_storage_insert(map, storage));
597 list_add(&storage->list_map, &map->list);
598 list_add(&storage->list_cg, &cgroup->bpf.storages);
599 spin_unlock_bh(&map->lock);
602 void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
604 struct bpf_cgroup_storage_map *map;
605 struct rb_root *root;
612 spin_lock_bh(&map->lock);
614 rb_erase(&storage->node, root);
616 list_del(&storage->list_map);
617 list_del(&storage->list_cg);
618 spin_unlock_bh(&map->lock);