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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#include <linux/slab.h>
#include <linux/bpf.h>
#include "map_in_map.h"
struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
{
struct bpf_map *inner_map, *inner_map_meta;
u32 inner_map_meta_size;
struct fd f;
f = fdget(inner_map_ufd);
inner_map = __bpf_map_get(f);
if (IS_ERR(inner_map))
return inner_map;
/* Does not support >1 level map-in-map */
if (inner_map->inner_map_meta) {
fdput(f);
return ERR_PTR(-EINVAL);
}
if (!inner_map->ops->map_meta_equal) {
fdput(f);
return ERR_PTR(-ENOTSUPP);
}
if (map_value_has_spin_lock(inner_map)) {
fdput(f);
return ERR_PTR(-ENOTSUPP);
}
inner_map_meta_size = sizeof(*inner_map_meta);
/* In some cases verifier needs to access beyond just base map. */
if (inner_map->ops == &array_map_ops)
inner_map_meta_size = sizeof(struct bpf_array);
inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
if (!inner_map_meta) {
fdput(f);
return ERR_PTR(-ENOMEM);
}
inner_map_meta->map_type = inner_map->map_type;
inner_map_meta->key_size = inner_map->key_size;
inner_map_meta->value_size = inner_map->value_size;
inner_map_meta->map_flags = inner_map->map_flags;
inner_map_meta->max_entries = inner_map->max_entries;
inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
/* Misc members not needed in bpf_map_meta_equal() check. */
inner_map_meta->ops = inner_map->ops;
if (inner_map->ops == &array_map_ops) {
inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
container_of(inner_map_meta, struct bpf_array, map)->index_mask =
container_of(inner_map, struct bpf_array, map)->index_mask;
}
fdput(f);
return inner_map_meta;
}
void bpf_map_meta_free(struct bpf_map *map_meta)
{
kfree(map_meta);
}
bool bpf_map_meta_equal(const struct bpf_map *meta0,
const struct bpf_map *meta1)
{
/* No need to compare ops because it is covered by map_type */
return meta0->map_type == meta1->map_type &&
meta0->key_size == meta1->key_size &&
meta0->value_size == meta1->value_size &&
meta0->map_flags == meta1->map_flags;
}
void *bpf_map_fd_get_ptr(struct bpf_map *map,
struct file *map_file /* not used */,
int ufd)
{
struct bpf_map *inner_map, *inner_map_meta;
struct fd f;
f = fdget(ufd);
inner_map = __bpf_map_get(f);
if (IS_ERR(inner_map))
return inner_map;
inner_map_meta = map->inner_map_meta;
if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
bpf_map_inc(inner_map);
else
inner_map = ERR_PTR(-EINVAL);
fdput(f);
return inner_map;
}
void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
{
struct bpf_map *inner_map = ptr;
/* The inner map may still be used by both non-sleepable and sleepable
* bpf program, so free it after one RCU grace period and one tasks
* trace RCU grace period.
*/
if (need_defer)
WRITE_ONCE(inner_map->free_after_mult_rcu_gp, true);
bpf_map_put(inner_map);
}
u32 bpf_map_fd_sys_lookup_elem(void *ptr)
{
return ((struct bpf_map *)ptr)->id;
}
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