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 #include <linux/btf.h>
7
8 #include "map_in_map.h"
9
bpf_map_meta_alloc(int inner_map_ufd)10 struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
11 {
12 struct bpf_map *inner_map, *inner_map_meta;
13 u32 inner_map_meta_size;
14 struct fd f;
15
16 f = fdget(inner_map_ufd);
17 inner_map = __bpf_map_get(f);
18 if (IS_ERR(inner_map))
19 return inner_map;
20
21 /* Does not support >1 level map-in-map */
22 if (inner_map->inner_map_meta) {
23 fdput(f);
24 return ERR_PTR(-EINVAL);
25 }
26
27 if (!inner_map->ops->map_meta_equal) {
28 fdput(f);
29 return ERR_PTR(-ENOTSUPP);
30 }
31
32 if (map_value_has_spin_lock(inner_map)) {
33 fdput(f);
34 return ERR_PTR(-ENOTSUPP);
35 }
36
37 inner_map_meta_size = sizeof(*inner_map_meta);
38 /* In some cases verifier needs to access beyond just base map. */
39 if (inner_map->ops == &array_map_ops)
40 inner_map_meta_size = sizeof(struct bpf_array);
41
42 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
43 if (!inner_map_meta) {
44 fdput(f);
45 return ERR_PTR(-ENOMEM);
46 }
47
48 inner_map_meta->map_type = inner_map->map_type;
49 inner_map_meta->key_size = inner_map->key_size;
50 inner_map_meta->value_size = inner_map->value_size;
51 inner_map_meta->map_flags = inner_map->map_flags;
52 inner_map_meta->max_entries = inner_map->max_entries;
53 inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
54 inner_map_meta->timer_off = inner_map->timer_off;
55 if (inner_map->btf) {
56 btf_get(inner_map->btf);
57 inner_map_meta->btf = inner_map->btf;
58 }
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
bpf_map_meta_free(struct bpf_map * map_meta)72 void bpf_map_meta_free(struct bpf_map *map_meta)
73 {
74 btf_put(map_meta->btf);
75 kfree(map_meta);
76 }
77
bpf_map_meta_equal(const struct bpf_map * meta0,const struct bpf_map * meta1)78 bool bpf_map_meta_equal(const struct bpf_map *meta0,
79 const struct bpf_map *meta1)
80 {
81 /* No need to compare ops because it is covered by map_type */
82 return meta0->map_type == meta1->map_type &&
83 meta0->key_size == meta1->key_size &&
84 meta0->value_size == meta1->value_size &&
85 meta0->timer_off == meta1->timer_off &&
86 meta0->map_flags == meta1->map_flags;
87 }
88
bpf_map_fd_get_ptr(struct bpf_map * map,struct file * map_file,int ufd)89 void *bpf_map_fd_get_ptr(struct bpf_map *map,
90 struct file *map_file /* not used */,
91 int ufd)
92 {
93 struct bpf_map *inner_map, *inner_map_meta;
94 struct fd f;
95
96 f = fdget(ufd);
97 inner_map = __bpf_map_get(f);
98 if (IS_ERR(inner_map))
99 return inner_map;
100
101 inner_map_meta = map->inner_map_meta;
102 if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
103 bpf_map_inc(inner_map);
104 else
105 inner_map = ERR_PTR(-EINVAL);
106
107 fdput(f);
108 return inner_map;
109 }
110
bpf_map_fd_put_ptr(void * ptr)111 void bpf_map_fd_put_ptr(void *ptr)
112 {
113 /* ptr->ops->map_free() has to go through one
114 * rcu grace period by itself.
115 */
116 bpf_map_put(ptr);
117 }
118
bpf_map_fd_sys_lookup_elem(void * ptr)119 u32 bpf_map_fd_sys_lookup_elem(void *ptr)
120 {
121 return ((struct bpf_map *)ptr)->id;
122 }
123