LXR linux/kernel/bpf/map_in

   1// SPDX-License-Identifier: GPL-2.0-only
   2/* Copyright (c) 2017 Facebook
   3 */
   4#include <linux/slab.h>
   5#include <linux/bpf.h>
   6
   7#include "map_in_map.h"
   8
   9struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
  10{
  11        struct bpf_map *inner_map, *inner_map_meta;
  12        u32 inner_map_meta_size;
  13        struct fd f;
  14
  15        f = fdget(inner_map_ufd);
  16        inner_map = __bpf_map_get(f);
  17        if (IS_ERR(inner_map))
  18                return inner_map;
  19
  20        /* prog_array->aux->{type,jited} is a runtime binding.
  21         * Doing static check alone in the verifier is not enough.
  22         */
  23        if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
  24            inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
  25            inner_map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE ||
  26            inner_map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
  27                fdput(f);
  28                return ERR_PTR(-ENOTSUPP);
  29        }
  30
  31        /* Does not support >1 level map-in-map */
  32        if (inner_map->inner_map_meta) {
  33                fdput(f);
  34                return ERR_PTR(-EINVAL);
  35        }
  36
  37        if (map_value_has_spin_lock(inner_map)) {
  38                fdput(f);
  39                return ERR_PTR(-ENOTSUPP);
  40        }
  41
  42        inner_map_meta_size = sizeof(*inner_map_meta);
  43        /* In some cases verifier needs to access beyond just base map. */
  44        if (inner_map->ops == &array_map_ops)
  45                inner_map_meta_size = sizeof(struct bpf_array);
  46
  47        inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
  48        if (!inner_map_meta) {
  49                fdput(f);
  50                return ERR_PTR(-ENOMEM);
  51        }
  52
  53        inner_map_meta->map_type = inner_map->map_type;
  54        inner_map_meta->key_size = inner_map->key_size;
  55        inner_map_meta->value_size = inner_map->value_size;
  56        inner_map_meta->map_flags = inner_map->map_flags;
  57        inner_map_meta->max_entries = inner_map->max_entries;
  58        inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
  59
  60        /* Misc members not needed in bpf_map_meta_equal() check. */
  61        inner_map_meta->ops = inner_map->ops;
  62        if (inner_map->ops == &array_map_ops) {
  63                inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
  64                container_of(inner_map_meta, struct bpf_array, map)->index_mask =
  65                     container_of(inner_map, struct bpf_array, map)->index_mask;
  66        }
  67
  68        fdput(f);
  69        return inner_map_meta;
  70}
  71
  72void bpf_map_meta_free(struct bpf_map *map_meta)
  73{
  74        kfree(map_meta);
  75}
  76
  77bool bpf_map_meta_equal(const struct bpf_map *meta0,
  78                        const struct bpf_map *meta1)
  79{
  80        /* No need to compare ops because it is covered by map_type */
  81        return meta0->map_type == meta1->map_type &&
  82                meta0->key_size == meta1->key_size &&
  83                meta0->value_size == meta1->value_size &&
  84                meta0->map_flags == meta1->map_flags &&
  85                meta0->max_entries == meta1->max_entries;
  86}
  87
  88void *bpf_map_fd_get_ptr(struct bpf_map *map,
  89                         struct file *map_file /* not used */,
  90                         int ufd)
  91{
  92        struct bpf_map *inner_map;
  93        struct fd f;
  94
  95        f = fdget(ufd);
  96        inner_map = __bpf_map_get(f);
  97        if (IS_ERR(inner_map))
  98                return inner_map;
  99
 100        if (bpf_map_meta_equal(map->inner_map_meta, inner_map))
 101                bpf_map_inc(inner_map);
 102        else
 103                inner_map = ERR_PTR(-EINVAL);
 104
 105        fdput(f);
 106        return inner_map;
 107}
 108
 109void bpf_map_fd_put_ptr(void *ptr)
 110{
 111        /* ptr->ops->map_free() has to go through one
 112         * rcu grace period by itself.
 113         */
 114        bpf_map_put(ptr);
 115}
 116
 117u32 bpf_map_fd_sys_lookup_elem(void *ptr)
 118{
 119        return ((struct bpf_map *)ptr)->id;
 120}
 121