| // 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_ATOMIC | __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 = kmalloc_node(sizeof(struct bpf_cgroup_storage_map), |
| __GFP_ZERO | GFP_USER | __GFP_ACCOUNT, 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; |
| |
| mutex_lock(&cgroup_mutex); |
| |
| list_for_each_entry_safe(storage, stmp, storages, list_map) { |
| bpf_cgroup_storage_unlink(storage); |
| bpf_cgroup_storage_free(storage); |
| } |
| |
| mutex_unlock(&cgroup_mutex); |
| |
| WARN_ON(!RB_EMPTY_ROOT(&map->root)); |
| WARN_ON(!list_empty(&map->list)); |
| |
| kfree(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 |