//SPDX-License-Identifier: GPL-2.0
|
#include <linux/bpf-cgroup.h>
|
#include <linux/bpf.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>
|
|
#ifdef CONFIG_CGROUP_BPF
|
|
DEFINE_PER_CPU(struct bpf_cgroup_storage_info,
|
bpf_cgroup_storage_info[BPF_CGROUP_STORAGE_NEST_MAX]);
|
|
#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 = kmalloc_node(sizeof(struct bpf_storage_buffer) +
|
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_lock(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)
|
{
|
int numa_node = bpf_map_attr_numa_node(attr);
|
struct bpf_cgroup_storage_map *map;
|
struct bpf_map_memory mem;
|
int ret;
|
|
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 > PAGE_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);
|
|
ret = bpf_map_charge_init(&mem, sizeof(struct bpf_cgroup_storage_map));
|
if (ret < 0)
|
return ERR_PTR(ret);
|
|
map = kmalloc_node(sizeof(struct bpf_cgroup_storage_map),
|
__GFP_ZERO | GFP_USER, numa_node);
|
if (!map) {
|
bpf_map_charge_finish(&mem);
|
return ERR_PTR(-ENOMEM);
|
}
|
|
bpf_map_charge_move(&map->map.memory, &mem);
|
|
/* 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 = cgroup_storage_type(map);
|
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();
|
}
|
|
static int cgroup_storage_map_btf_id;
|
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_name = "bpf_cgroup_storage_map",
|
.map_btf_id = &cgroup_storage_map_btf_id,
|
};
|
|
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)
|
{
|
struct bpf_cgroup_storage *storage;
|
struct bpf_map *map;
|
gfp_t flags;
|
size_t size;
|
u32 pages;
|
|
map = prog->aux->cgroup_storage[stype];
|
if (!map)
|
return NULL;
|
|
size = bpf_cgroup_storage_calculate_size(map, &pages);
|
|
if (bpf_map_charge_memlock(map, pages))
|
return ERR_PTR(-EPERM);
|
|
storage = kmalloc_node(sizeof(struct bpf_cgroup_storage),
|
__GFP_ZERO | GFP_USER, map->numa_node);
|
if (!storage)
|
goto enomem;
|
|
flags = __GFP_ZERO | GFP_USER;
|
|
if (stype == BPF_CGROUP_STORAGE_SHARED) {
|
storage->buf = kmalloc_node(size, flags, map->numa_node);
|
if (!storage->buf)
|
goto enomem;
|
check_and_init_map_lock(map, storage->buf->data);
|
} else {
|
storage->percpu_buf = __alloc_percpu_gfp(size, 8, flags);
|
if (!storage->percpu_buf)
|
goto enomem;
|
}
|
|
storage->map = (struct bpf_cgroup_storage_map *)map;
|
|
return storage;
|
|
enomem:
|
bpf_map_uncharge_memlock(map, pages);
|
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;
|
u32 pages;
|
|
if (!storage)
|
return;
|
|
map = &storage->map->map;
|
|
bpf_cgroup_storage_calculate_size(map, &pages);
|
bpf_map_uncharge_memlock(map, pages);
|
|
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
|
