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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/bpf-cgroup.h>
- #include <linux/bpf.h>
- #include <linux/bpf_local_storage.h>
- #include <linux/btf.h>
- #include <linux/bug.h>
- #include <linux/filter.h>
- #include <linux/mm.h>
- #include <linux/rbtree.h>
- #include <linux/slab.h>
- #include <uapi/linux/btf.h>
- #include <linux/btf_ids.h>
- #ifdef CONFIG_CGROUP_BPF
- #include "../cgroup/cgroup-internal.h"
- #define LOCAL_STORAGE_CREATE_FLAG_MASK \
- (BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
- struct bpf_cgroup_storage_map {
- struct bpf_map map;
- spinlock_t lock;
- struct rb_root root;
- struct list_head list;
- };
- static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map)
- {
- return container_of(map, struct bpf_cgroup_storage_map, map);
- }
- static bool attach_type_isolated(const struct bpf_map *map)
- {
- return map->key_size == sizeof(struct bpf_cgroup_storage_key);
- }
- static int bpf_cgroup_storage_key_cmp(const struct bpf_cgroup_storage_map *map,
- const void *_key1, const void *_key2)
- {
- if (attach_type_isolated(&map->map)) {
- const struct bpf_cgroup_storage_key *key1 = _key1;
- const struct bpf_cgroup_storage_key *key2 = _key2;
- if (key1->cgroup_inode_id < key2->cgroup_inode_id)
- return -1;
- else if (key1->cgroup_inode_id > key2->cgroup_inode_id)
- return 1;
- else if (key1->attach_type < key2->attach_type)
- return -1;
- else if (key1->attach_type > key2->attach_type)
- return 1;
- } else {
- const __u64 *cgroup_inode_id1 = _key1;
- const __u64 *cgroup_inode_id2 = _key2;
- if (*cgroup_inode_id1 < *cgroup_inode_id2)
- return -1;
- else if (*cgroup_inode_id1 > *cgroup_inode_id2)
- return 1;
- }
- return 0;
- }
- struct bpf_cgroup_storage *
- cgroup_storage_lookup(struct bpf_cgroup_storage_map *map,
- void *key, bool locked)
- {
- struct rb_root *root = &map->root;
- struct rb_node *node;
- if (!locked)
- spin_lock_bh(&map->lock);
- node = root->rb_node;
- while (node) {
- struct bpf_cgroup_storage *storage;
- storage = container_of(node, struct bpf_cgroup_storage, node);
- switch (bpf_cgroup_storage_key_cmp(map, key, &storage->key)) {
- case -1:
- node = node->rb_left;
- break;
- case 1:
- node = node->rb_right;
- break;
- default:
- if (!locked)
- spin_unlock_bh(&map->lock);
- return storage;
- }
- }
- if (!locked)
- spin_unlock_bh(&map->lock);
- return NULL;
- }
- static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map,
- struct bpf_cgroup_storage *storage)
- {
- struct rb_root *root = &map->root;
- struct rb_node **new = &(root->rb_node), *parent = NULL;
- while (*new) {
- struct bpf_cgroup_storage *this;
- this = container_of(*new, struct bpf_cgroup_storage, node);
- parent = *new;
- switch (bpf_cgroup_storage_key_cmp(map, &storage->key, &this->key)) {
- case -1:
- new = &((*new)->rb_left);
- break;
- case 1:
- new = &((*new)->rb_right);
- break;
- default:
- return -EEXIST;
- }
- }
- rb_link_node(&storage->node, parent, new);
- rb_insert_color(&storage->node, root);
- return 0;
- }
- static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *key)
- {
- struct bpf_cgroup_storage_map *map = map_to_storage(_map);
- struct bpf_cgroup_storage *storage;
- storage = cgroup_storage_lookup(map, key, false);
- if (!storage)
- return NULL;
- return &READ_ONCE(storage->buf)->data[0];
- }
- static int cgroup_storage_update_elem(struct bpf_map *map, void *key,
- void *value, u64 flags)
- {
- struct bpf_cgroup_storage *storage;
- struct bpf_storage_buffer *new;
- if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST)))
- return -EINVAL;
- if (unlikely((flags & BPF_F_LOCK) &&
- !map_value_has_spin_lock(map)))
- return -EINVAL;
- storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
- key, false);
- if (!storage)
- return -ENOENT;
- if (flags & BPF_F_LOCK) {
- copy_map_value_locked(map, storage->buf->data, value, false);
- return 0;
- }
- new = bpf_map_kmalloc_node(map, struct_size(new, data, map->value_size),
- __GFP_ZERO | GFP_NOWAIT | __GFP_NOWARN,
- map->numa_node);
- if (!new)
- return -ENOMEM;
- memcpy(&new->data[0], value, map->value_size);
- check_and_init_map_value(map, new->data);
- new = xchg(&storage->buf, new);
- kfree_rcu(new, rcu);
- return 0;
- }
- int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,
- void *value)
- {
- struct bpf_cgroup_storage_map *map = map_to_storage(_map);
- struct bpf_cgroup_storage *storage;
- int cpu, off = 0;
- u32 size;
- rcu_read_lock();
- storage = cgroup_storage_lookup(map, key, false);
- if (!storage) {
- rcu_read_unlock();
- return -ENOENT;
- }
- /* per_cpu areas are zero-filled and bpf programs can only
- * access 'value_size' of them, so copying rounded areas
- * will not leak any kernel data
- */
- size = round_up(_map->value_size, 8);
- for_each_possible_cpu(cpu) {
- bpf_long_memcpy(value + off,
- per_cpu_ptr(storage->percpu_buf, cpu), size);
- off += size;
- }
- rcu_read_unlock();
- return 0;
- }
- int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key,
- void *value, u64 map_flags)
- {
- struct bpf_cgroup_storage_map *map = map_to_storage(_map);
- struct bpf_cgroup_storage *storage;
- int cpu, off = 0;
- u32 size;
- if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
- return -EINVAL;
- rcu_read_lock();
- storage = cgroup_storage_lookup(map, key, false);
- if (!storage) {
- rcu_read_unlock();
- return -ENOENT;
- }
- /* the user space will provide round_up(value_size, 8) bytes that
- * will be copied into per-cpu area. bpf programs can only access
- * value_size of it. During lookup the same extra bytes will be
- * returned or zeros which were zero-filled by percpu_alloc,
- * so no kernel data leaks possible
- */
- size = round_up(_map->value_size, 8);
- for_each_possible_cpu(cpu) {
- bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu),
- value + off, size);
- off += size;
- }
- rcu_read_unlock();
- return 0;
- }
- static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key,
- void *_next_key)
- {
- struct bpf_cgroup_storage_map *map = map_to_storage(_map);
- struct bpf_cgroup_storage *storage;
- spin_lock_bh(&map->lock);
- if (list_empty(&map->list))
- goto enoent;
- if (key) {
- storage = cgroup_storage_lookup(map, key, true);
- if (!storage)
- goto enoent;
- storage = list_next_entry(storage, list_map);
- if (!storage)
- goto enoent;
- } else {
- storage = list_first_entry(&map->list,
- struct bpf_cgroup_storage, list_map);
- }
- spin_unlock_bh(&map->lock);
- if (attach_type_isolated(&map->map)) {
- struct bpf_cgroup_storage_key *next = _next_key;
- *next = storage->key;
- } else {
- __u64 *next = _next_key;
- *next = storage->key.cgroup_inode_id;
- }
- return 0;
- enoent:
- spin_unlock_bh(&map->lock);
- return -ENOENT;
- }
- static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
- {
- __u32 max_value_size = BPF_LOCAL_STORAGE_MAX_VALUE_SIZE;
- int numa_node = bpf_map_attr_numa_node(attr);
- struct bpf_cgroup_storage_map *map;
- /* percpu is bound by PCPU_MIN_UNIT_SIZE, non-percu
- * is the same as other local storages.
- */
- if (attr->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
- max_value_size = min_t(__u32, max_value_size,
- PCPU_MIN_UNIT_SIZE);
- if (attr->key_size != sizeof(struct bpf_cgroup_storage_key) &&
- attr->key_size != sizeof(__u64))
- return ERR_PTR(-EINVAL);
- if (attr->value_size == 0)
- return ERR_PTR(-EINVAL);
- if (attr->value_size > max_value_size)
- return ERR_PTR(-E2BIG);
- if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
- !bpf_map_flags_access_ok(attr->map_flags))
- return ERR_PTR(-EINVAL);
- if (attr->max_entries)
- /* max_entries is not used and enforced to be 0 */
- return ERR_PTR(-EINVAL);
- map = bpf_map_area_alloc(sizeof(struct bpf_cgroup_storage_map), numa_node);
- if (!map)
- return ERR_PTR(-ENOMEM);
- /* copy mandatory map attributes */
- bpf_map_init_from_attr(&map->map, attr);
- spin_lock_init(&map->lock);
- map->root = RB_ROOT;
- INIT_LIST_HEAD(&map->list);
- return &map->map;
- }
- static void cgroup_storage_map_free(struct bpf_map *_map)
- {
- struct bpf_cgroup_storage_map *map = map_to_storage(_map);
- struct list_head *storages = &map->list;
- struct bpf_cgroup_storage *storage, *stmp;
- cgroup_lock();
- list_for_each_entry_safe(storage, stmp, storages, list_map) {
- bpf_cgroup_storage_unlink(storage);
- bpf_cgroup_storage_free(storage);
- }
- cgroup_unlock();
- WARN_ON(!RB_EMPTY_ROOT(&map->root));
- WARN_ON(!list_empty(&map->list));
- bpf_map_area_free(map);
- }
- static int cgroup_storage_delete_elem(struct bpf_map *map, void *key)
- {
- return -EINVAL;
- }
- static int cgroup_storage_check_btf(const struct bpf_map *map,
- const struct btf *btf,
- const struct btf_type *key_type,
- const struct btf_type *value_type)
- {
- if (attach_type_isolated(map)) {
- struct btf_member *m;
- u32 offset, size;
- /* Key is expected to be of struct bpf_cgroup_storage_key type,
- * which is:
- * struct bpf_cgroup_storage_key {
- * __u64 cgroup_inode_id;
- * __u32 attach_type;
- * };
- */
- /*
- * Key_type must be a structure with two fields.
- */
- if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ||
- BTF_INFO_VLEN(key_type->info) != 2)
- return -EINVAL;
- /*
- * The first field must be a 64 bit integer at 0 offset.
- */
- m = (struct btf_member *)(key_type + 1);
- size = sizeof_field(struct bpf_cgroup_storage_key, cgroup_inode_id);
- if (!btf_member_is_reg_int(btf, key_type, m, 0, size))
- return -EINVAL;
- /*
- * The second field must be a 32 bit integer at 64 bit offset.
- */
- m++;
- offset = offsetof(struct bpf_cgroup_storage_key, attach_type);
- size = sizeof_field(struct bpf_cgroup_storage_key, attach_type);
- if (!btf_member_is_reg_int(btf, key_type, m, offset, size))
- return -EINVAL;
- } else {
- u32 int_data;
- /*
- * Key is expected to be u64, which stores the cgroup_inode_id
- */
- if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
- return -EINVAL;
- int_data = *(u32 *)(key_type + 1);
- if (BTF_INT_BITS(int_data) != 64 || BTF_INT_OFFSET(int_data))
- return -EINVAL;
- }
- return 0;
- }
- static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *key,
- struct seq_file *m)
- {
- enum bpf_cgroup_storage_type stype;
- struct bpf_cgroup_storage *storage;
- int cpu;
- rcu_read_lock();
- storage = cgroup_storage_lookup(map_to_storage(map), key, false);
- if (!storage) {
- rcu_read_unlock();
- return;
- }
- btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
- stype = cgroup_storage_type(map);
- if (stype == BPF_CGROUP_STORAGE_SHARED) {
- seq_puts(m, ": ");
- btf_type_seq_show(map->btf, map->btf_value_type_id,
- &READ_ONCE(storage->buf)->data[0], m);
- seq_puts(m, "\n");
- } else {
- seq_puts(m, ": {\n");
- for_each_possible_cpu(cpu) {
- seq_printf(m, "\tcpu%d: ", cpu);
- btf_type_seq_show(map->btf, map->btf_value_type_id,
- per_cpu_ptr(storage->percpu_buf, cpu),
- m);
- seq_puts(m, "\n");
- }
- seq_puts(m, "}\n");
- }
- rcu_read_unlock();
- }
- BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct,
- bpf_cgroup_storage_map)
- const struct bpf_map_ops cgroup_storage_map_ops = {
- .map_alloc = cgroup_storage_map_alloc,
- .map_free = cgroup_storage_map_free,
- .map_get_next_key = cgroup_storage_get_next_key,
- .map_lookup_elem = cgroup_storage_lookup_elem,
- .map_update_elem = cgroup_storage_update_elem,
- .map_delete_elem = cgroup_storage_delete_elem,
- .map_check_btf = cgroup_storage_check_btf,
- .map_seq_show_elem = cgroup_storage_seq_show_elem,
- .map_btf_id = &cgroup_storage_map_btf_ids[0],
- };
- int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map)
- {
- enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
- if (aux->cgroup_storage[stype] &&
- aux->cgroup_storage[stype] != _map)
- return -EBUSY;
- aux->cgroup_storage[stype] = _map;
- return 0;
- }
- static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages)
- {
- size_t size;
- if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) {
- size = sizeof(struct bpf_storage_buffer) + map->value_size;
- *pages = round_up(sizeof(struct bpf_cgroup_storage) + size,
- PAGE_SIZE) >> PAGE_SHIFT;
- } else {
- size = map->value_size;
- *pages = round_up(round_up(size, 8) * num_possible_cpus(),
- PAGE_SIZE) >> PAGE_SHIFT;
- }
- return size;
- }
- struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
- enum bpf_cgroup_storage_type stype)
- {
- const gfp_t gfp = __GFP_ZERO | GFP_USER;
- struct bpf_cgroup_storage *storage;
- struct bpf_map *map;
- size_t size;
- u32 pages;
- map = prog->aux->cgroup_storage[stype];
- if (!map)
- return NULL;
- size = bpf_cgroup_storage_calculate_size(map, &pages);
- storage = bpf_map_kmalloc_node(map, sizeof(struct bpf_cgroup_storage),
- gfp, map->numa_node);
- if (!storage)
- goto enomem;
- if (stype == BPF_CGROUP_STORAGE_SHARED) {
- storage->buf = bpf_map_kmalloc_node(map, size, gfp,
- map->numa_node);
- if (!storage->buf)
- goto enomem;
- check_and_init_map_value(map, storage->buf->data);
- } else {
- storage->percpu_buf = bpf_map_alloc_percpu(map, size, 8, gfp);
- if (!storage->percpu_buf)
- goto enomem;
- }
- storage->map = (struct bpf_cgroup_storage_map *)map;
- return storage;
- enomem:
- kfree(storage);
- return ERR_PTR(-ENOMEM);
- }
- static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
- {
- struct bpf_cgroup_storage *storage =
- container_of(rcu, struct bpf_cgroup_storage, rcu);
- kfree(storage->buf);
- kfree(storage);
- }
- static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
- {
- struct bpf_cgroup_storage *storage =
- container_of(rcu, struct bpf_cgroup_storage, rcu);
- free_percpu(storage->percpu_buf);
- kfree(storage);
- }
- void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
- {
- enum bpf_cgroup_storage_type stype;
- struct bpf_map *map;
- if (!storage)
- return;
- map = &storage->map->map;
- stype = cgroup_storage_type(map);
- if (stype == BPF_CGROUP_STORAGE_SHARED)
- call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
- else
- call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);
- }
- void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
- struct cgroup *cgroup,
- enum bpf_attach_type type)
- {
- struct bpf_cgroup_storage_map *map;
- if (!storage)
- return;
- storage->key.attach_type = type;
- storage->key.cgroup_inode_id = cgroup_id(cgroup);
- map = storage->map;
- spin_lock_bh(&map->lock);
- WARN_ON(cgroup_storage_insert(map, storage));
- list_add(&storage->list_map, &map->list);
- list_add(&storage->list_cg, &cgroup->bpf.storages);
- spin_unlock_bh(&map->lock);
- }
- void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
- {
- struct bpf_cgroup_storage_map *map;
- struct rb_root *root;
- if (!storage)
- return;
- map = storage->map;
- spin_lock_bh(&map->lock);
- root = &map->root;
- rb_erase(&storage->node, root);
- list_del(&storage->list_map);
- list_del(&storage->list_cg);
- spin_unlock_bh(&map->lock);
- }
- #endif
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