Commit de9cbbaa authored by Roman Gushchin's avatar Roman Gushchin Committed by Daniel Borkmann

bpf: introduce cgroup storage maps

This commit introduces BPF_MAP_TYPE_CGROUP_STORAGE maps:
a special type of maps which are implementing the cgroup storage.

>From the userspace point of view it's almost a generic
hash map with the (cgroup inode id, attachment type) pair
used as a key.

The only difference is that some operations are restricted:
  1) a user can't create new entries,
  2) a user can't remove existing entries.

The lookup from userspace is o(log(n)).
Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 0a4c58f5
......@@ -4,19 +4,39 @@
#include <linux/errno.h>
#include <linux/jump_label.h>
#include <linux/rbtree.h>
#include <uapi/linux/bpf.h>
struct sock;
struct sockaddr;
struct cgroup;
struct sk_buff;
struct bpf_map;
struct bpf_prog;
struct bpf_sock_ops_kern;
struct bpf_cgroup_storage;
#ifdef CONFIG_CGROUP_BPF
extern struct static_key_false cgroup_bpf_enabled_key;
#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
struct bpf_cgroup_storage_map;
struct bpf_storage_buffer {
struct rcu_head rcu;
char data[0];
};
struct bpf_cgroup_storage {
struct bpf_storage_buffer *buf;
struct bpf_cgroup_storage_map *map;
struct bpf_cgroup_storage_key key;
struct list_head list;
struct rb_node node;
struct rcu_head rcu;
};
struct bpf_prog_list {
struct list_head node;
struct bpf_prog *prog;
......@@ -77,6 +97,15 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
short access, enum bpf_attach_type type);
struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog);
void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage);
void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
struct cgroup *cgroup,
enum bpf_attach_type type);
void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage);
int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *map);
void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *map);
/* Wrappers for __cgroup_bpf_run_filter_skb() guarded by cgroup_bpf_enabled. */
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb) \
({ \
......@@ -221,6 +250,15 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr,
return -EINVAL;
}
static inline int bpf_cgroup_storage_assign(struct bpf_prog *prog,
struct bpf_map *map) { return 0; }
static inline void bpf_cgroup_storage_release(struct bpf_prog *prog,
struct bpf_map *map) {}
static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(
struct bpf_prog *prog) { return 0; }
static inline void bpf_cgroup_storage_free(
struct bpf_cgroup_storage *storage) {}
#define cgroup_bpf_enabled (0)
#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0)
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
......
......@@ -282,6 +282,7 @@ struct bpf_prog_aux {
struct bpf_prog *prog;
struct user_struct *user;
u64 load_time; /* ns since boottime */
struct bpf_map *cgroup_storage;
char name[BPF_OBJ_NAME_LEN];
#ifdef CONFIG_SECURITY
void *security;
......
......@@ -37,6 +37,9 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_PERF_EVENT_ARRAY, perf_event_array_map_ops)
#ifdef CONFIG_CGROUPS
BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_ARRAY, cgroup_array_map_ops)
#endif
#ifdef CONFIG_CGROUP_BPF
BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_STORAGE, cgroup_storage_map_ops)
#endif
BPF_MAP_TYPE(BPF_MAP_TYPE_HASH, htab_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_HASH, htab_percpu_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_HASH, htab_lru_map_ops)
......
......@@ -75,6 +75,11 @@ struct bpf_lpm_trie_key {
__u8 data[0]; /* Arbitrary size */
};
struct bpf_cgroup_storage_key {
__u64 cgroup_inode_id; /* cgroup inode id */
__u32 attach_type; /* program attach type */
};
/* BPF syscall commands, see bpf(2) man-page for details. */
enum bpf_cmd {
BPF_MAP_CREATE,
......@@ -120,6 +125,7 @@ enum bpf_map_type {
BPF_MAP_TYPE_CPUMAP,
BPF_MAP_TYPE_XSKMAP,
BPF_MAP_TYPE_SOCKHASH,
BPF_MAP_TYPE_CGROUP_STORAGE,
};
enum bpf_prog_type {
......
......@@ -3,6 +3,7 @@ obj-y := core.o
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o
obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o
obj-$(CONFIG_BPF_SYSCALL) += local_storage.o
obj-$(CONFIG_BPF_SYSCALL) += disasm.o
obj-$(CONFIG_BPF_SYSCALL) += btf.o
ifeq ($(CONFIG_NET),y)
......
//SPDX-License-Identifier: GPL-2.0
#include <linux/bpf-cgroup.h>
#include <linux/bpf.h>
#include <linux/bug.h>
#include <linux/filter.h>
#include <linux/mm.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#ifdef CONFIG_CGROUP_BPF
#define LOCAL_STORAGE_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
struct bpf_cgroup_storage_map {
struct bpf_map map;
spinlock_t lock;
struct bpf_prog *prog;
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 int bpf_cgroup_storage_key_cmp(
const struct bpf_cgroup_storage_key *key1,
const struct bpf_cgroup_storage_key *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;
return 0;
}
static struct bpf_cgroup_storage *cgroup_storage_lookup(
struct bpf_cgroup_storage_map *map, struct bpf_cgroup_storage_key *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(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(&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_key *key = _key;
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_key *key = _key;
struct bpf_cgroup_storage *storage;
struct bpf_storage_buffer *new;
if (flags & BPF_NOEXIST)
return -EINVAL;
storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
key, false);
if (!storage)
return -ENOENT;
new = kmalloc_node(sizeof(struct bpf_storage_buffer) +
map->value_size, __GFP_ZERO | GFP_USER,
map->numa_node);
if (!new)
return -ENOMEM;
memcpy(&new->data[0], value, map->value_size);
new = xchg(&storage->buf, new);
kfree_rcu(new, rcu);
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_key *key = _key;
struct bpf_cgroup_storage_key *next = _next_key;
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);
if (!storage)
goto enoent;
} else {
storage = list_first_entry(&map->list,
struct bpf_cgroup_storage, list);
}
spin_unlock_bh(&map->lock);
next->attach_type = storage->key.attach_type;
next->cgroup_inode_id = 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;
if (attr->key_size != sizeof(struct bpf_cgroup_storage_key))
return ERR_PTR(-EINVAL);
if (attr->value_size > PAGE_SIZE)
return ERR_PTR(-E2BIG);
if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK)
/* reserved bits should not be used */
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, numa_node);
if (!map)
return ERR_PTR(-ENOMEM);
map->map.pages = round_up(sizeof(struct bpf_cgroup_storage_map),
PAGE_SIZE) >> PAGE_SHIFT;
/* 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);
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;
}
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,
};
int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
{
struct bpf_cgroup_storage_map *map = map_to_storage(_map);
int ret = -EBUSY;
spin_lock_bh(&map->lock);
if (map->prog && map->prog != prog)
goto unlock;
if (prog->aux->cgroup_storage && prog->aux->cgroup_storage != _map)
goto unlock;
map->prog = prog;
prog->aux->cgroup_storage = _map;
ret = 0;
unlock:
spin_unlock_bh(&map->lock);
return ret;
}
void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map)
{
struct bpf_cgroup_storage_map *map = map_to_storage(_map);
spin_lock_bh(&map->lock);
if (map->prog == prog) {
WARN_ON(prog->aux->cgroup_storage != _map);
map->prog = NULL;
prog->aux->cgroup_storage = NULL;
}
spin_unlock_bh(&map->lock);
}
struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog)
{
struct bpf_cgroup_storage *storage;
struct bpf_map *map;
u32 pages;
map = prog->aux->cgroup_storage;
if (!map)
return NULL;
pages = round_up(sizeof(struct bpf_cgroup_storage) +
sizeof(struct bpf_storage_buffer) +
map->value_size, PAGE_SIZE) >> PAGE_SHIFT;
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) {
bpf_map_uncharge_memlock(map, pages);
return ERR_PTR(-ENOMEM);
}
storage->buf = kmalloc_node(sizeof(struct bpf_storage_buffer) +
map->value_size, __GFP_ZERO | GFP_USER,
map->numa_node);
if (!storage->buf) {
bpf_map_uncharge_memlock(map, pages);
kfree(storage);
return ERR_PTR(-ENOMEM);
}
storage->map = (struct bpf_cgroup_storage_map *)map;
return storage;
}
void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
{
u32 pages;
struct bpf_map *map;
if (!storage)
return;
map = &storage->map->map;
pages = round_up(sizeof(struct bpf_cgroup_storage) +
sizeof(struct bpf_storage_buffer) +
map->value_size, PAGE_SIZE) >> PAGE_SHIFT;
bpf_map_uncharge_memlock(map, pages);
kfree_rcu(storage->buf, rcu);
kfree_rcu(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->kn->id.id;
map = storage->map;
spin_lock_bh(&map->lock);
WARN_ON(cgroup_storage_insert(map, storage));
list_add(&storage->list, &map->list);
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);
spin_unlock_bh(&map->lock);
}
#endif
......@@ -957,6 +957,9 @@ static void free_used_maps(struct bpf_prog_aux *aux)
{
int i;
if (aux->cgroup_storage)
bpf_cgroup_storage_release(aux->prog, aux->cgroup_storage);
for (i = 0; i < aux->used_map_cnt; i++)
bpf_map_put(aux->used_maps[i]);
......
......@@ -5154,6 +5154,14 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
}
env->used_maps[env->used_map_cnt++] = map;
if (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE &&
bpf_cgroup_storage_assign(env->prog, map)) {
verbose(env,
"only one cgroup storage is allowed\n");
fdput(f);
return -EBUSY;
}
fdput(f);
next_insn:
insn++;
......@@ -5180,6 +5188,10 @@ static void release_maps(struct bpf_verifier_env *env)
{
int i;
if (env->prog->aux->cgroup_storage)
bpf_cgroup_storage_release(env->prog,
env->prog->aux->cgroup_storage);
for (i = 0; i < env->used_map_cnt; i++)
bpf_map_put(env->used_maps[i]);
}
......
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