1 /* Copyright (c) 2017 Facebook
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 #include <linux/slab.h>
10 #include "map_in_map.h"
12 struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
14 struct bpf_map *inner_map, *inner_map_meta;
15 u32 inner_map_meta_size;
18 f = fdget(inner_map_ufd);
19 inner_map = __bpf_map_get(f);
20 if (IS_ERR(inner_map))
23 /* prog_array->owner_prog_type and owner_jited
24 * is a runtime binding. Doing static check alone
25 * in the verifier is not enough.
27 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
28 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE) {
30 return ERR_PTR(-ENOTSUPP);
33 /* Does not support >1 level map-in-map */
34 if (inner_map->inner_map_meta) {
36 return ERR_PTR(-EINVAL);
39 inner_map_meta_size = sizeof(*inner_map_meta);
40 /* In some cases verifier needs to access beyond just base map. */
41 if (inner_map->ops == &array_map_ops)
42 inner_map_meta_size = sizeof(struct bpf_array);
44 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
45 if (!inner_map_meta) {
47 return ERR_PTR(-ENOMEM);
50 inner_map_meta->map_type = inner_map->map_type;
51 inner_map_meta->key_size = inner_map->key_size;
52 inner_map_meta->value_size = inner_map->value_size;
53 inner_map_meta->map_flags = inner_map->map_flags;
54 inner_map_meta->max_entries = inner_map->max_entries;
56 /* Misc members not needed in bpf_map_meta_equal() check. */
57 inner_map_meta->ops = inner_map->ops;
58 if (inner_map->ops == &array_map_ops) {
59 inner_map_meta->unpriv_array = inner_map->unpriv_array;
60 container_of(inner_map_meta, struct bpf_array, map)->index_mask =
61 container_of(inner_map, struct bpf_array, map)->index_mask;
65 return inner_map_meta;
68 void bpf_map_meta_free(struct bpf_map *map_meta)
73 bool bpf_map_meta_equal(const struct bpf_map *meta0,
74 const struct bpf_map *meta1)
76 /* No need to compare ops because it is covered by map_type */
77 return meta0->map_type == meta1->map_type &&
78 meta0->key_size == meta1->key_size &&
79 meta0->value_size == meta1->value_size &&
80 meta0->map_flags == meta1->map_flags &&
81 meta0->max_entries == meta1->max_entries;
84 void *bpf_map_fd_get_ptr(struct bpf_map *map,
85 struct file *map_file /* not used */,
88 struct bpf_map *inner_map;
92 inner_map = __bpf_map_get(f);
93 if (IS_ERR(inner_map))
96 if (bpf_map_meta_equal(map->inner_map_meta, inner_map))
97 inner_map = bpf_map_inc(inner_map, false);
99 inner_map = ERR_PTR(-EINVAL);
105 void bpf_map_fd_put_ptr(void *ptr)
107 /* ptr->ops->map_free() has to go through one
108 * rcu grace period by itself.
113 u32 bpf_map_fd_sys_lookup_elem(void *ptr)
115 return ((struct bpf_map *)ptr)->id;