1 files changed, 614 insertions, 0 deletions

diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
new file mode 100644
index 0000000000..a04f505aef
--- /dev/null
+++ b/kernel/bpf/local_storage.c
@@ -0,0 +1,614 @@
+// 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 long 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) &&
+		     !btf_record_has_field(map->record, BPF_SPIN_LOCK)))
+		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 long 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();
+}
+
+static u64 cgroup_storage_map_usage(const struct bpf_map *map)
+{
+	/* Currently the dynamically allocated elements are not counted. */
+	return sizeof(struct bpf_cgroup_storage_map);
+}
+
+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_mem_usage = cgroup_storage_map_usage,
+	.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