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
bpf_map_meta_alloc(int inner_map_ufd)9 struct 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 /* Does not support >1 level map-in-map */
21 if (inner_map->inner_map_meta) {
22 fdput(f);
23 return ERR_PTR(-EINVAL);
24 }
25
26 if (!inner_map->ops->map_meta_equal) {
27 fdput(f);
28 return ERR_PTR(-ENOTSUPP);
29 }
30
31 if (map_value_has_spin_lock(inner_map)) {
32 fdput(f);
33 return ERR_PTR(-ENOTSUPP);
34 }
35
36 inner_map_meta_size = sizeof(*inner_map_meta);
37 /* In some cases verifier needs to access beyond just base map. */
38 if (inner_map->ops == &array_map_ops)
39 inner_map_meta_size = sizeof(struct bpf_array);
40
41 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
42 if (!inner_map_meta) {
43 fdput(f);
44 return ERR_PTR(-ENOMEM);
45 }
46
47 inner_map_meta->map_type = inner_map->map_type;
48 inner_map_meta->key_size = inner_map->key_size;
49 inner_map_meta->value_size = inner_map->value_size;
50 inner_map_meta->map_flags = inner_map->map_flags;
51 inner_map_meta->max_entries = inner_map->max_entries;
52 inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
53
54 /* Misc members not needed in bpf_map_meta_equal() check. */
55 inner_map_meta->ops = inner_map->ops;
56 if (inner_map->ops == &array_map_ops) {
57 inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
58 container_of(inner_map_meta, struct bpf_array, map)->index_mask =
59 container_of(inner_map, struct bpf_array, map)->index_mask;
60 }
61
62 fdput(f);
63 return inner_map_meta;
64 }
65
bpf_map_meta_free(struct bpf_map * map_meta)66 void bpf_map_meta_free(struct bpf_map *map_meta)
67 {
68 kfree(map_meta);
69 }
70
bpf_map_meta_equal(const struct bpf_map * meta0,const struct bpf_map * meta1)71 bool bpf_map_meta_equal(const struct bpf_map *meta0,
72 const struct bpf_map *meta1)
73 {
74 /* No need to compare ops because it is covered by map_type */
75 return meta0->map_type == meta1->map_type &&
76 meta0->key_size == meta1->key_size &&
77 meta0->value_size == meta1->value_size &&
78 meta0->map_flags == meta1->map_flags;
79 }
80
bpf_map_fd_get_ptr(struct bpf_map * map,struct file * map_file,int ufd)81 void *bpf_map_fd_get_ptr(struct bpf_map *map,
82 struct file *map_file /* not used */,
83 int ufd)
84 {
85 struct bpf_map *inner_map, *inner_map_meta;
86 struct fd f;
87
88 f = fdget(ufd);
89 inner_map = __bpf_map_get(f);
90 if (IS_ERR(inner_map))
91 return inner_map;
92
93 inner_map_meta = map->inner_map_meta;
94 if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
95 bpf_map_inc(inner_map);
96 else
97 inner_map = ERR_PTR(-EINVAL);
98
99 fdput(f);
100 return inner_map;
101 }
102
bpf_map_fd_put_ptr(void * ptr)103 void bpf_map_fd_put_ptr(void *ptr)
104 {
105 /* ptr->ops->map_free() has to go through one
106 * rcu grace period by itself.
107 */
108 bpf_map_put(ptr);
109 }
110
bpf_map_fd_sys_lookup_elem(void * ptr)111 u32 bpf_map_fd_sys_lookup_elem(void *ptr)
112 {
113 return ((struct bpf_map *)ptr)->id;
114 }
115