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-rw-r--r--kernel/bpf/local_storage.c607
1 files changed, 607 insertions, 0 deletions
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
new file mode 100644
index 000000000..f01ca6f1e
--- /dev/null
+++ b/kernel/bpf/local_storage.c
@@ -0,0 +1,607 @@
+// 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
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-07 14:41:39 +0000