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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
10struct 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 int ret;
16
17 f = fdget(inner_map_ufd);
18 inner_map = __bpf_map_get(f);
19 if (IS_ERR(inner_map))
20 return inner_map;
21
22 /* Does not support >1 level map-in-map */
23 if (inner_map->inner_map_meta) {
24 ret = -EINVAL;
25 goto put;
26 }
27
28 if (!inner_map->ops->map_meta_equal) {
29 ret = -ENOTSUPP;
30 goto put;
31 }
32
33 inner_map_meta_size = sizeof(*inner_map_meta);
34 /* In some cases verifier needs to access beyond just base map. */
35 if (inner_map->ops == &array_map_ops)
36 inner_map_meta_size = sizeof(struct bpf_array);
37
38 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
39 if (!inner_map_meta) {
40 ret = -ENOMEM;
41 goto put;
42 }
43
44 inner_map_meta->map_type = inner_map->map_type;
45 inner_map_meta->key_size = inner_map->key_size;
46 inner_map_meta->value_size = inner_map->value_size;
47 inner_map_meta->map_flags = inner_map->map_flags;
48 inner_map_meta->max_entries = inner_map->max_entries;
49
50 inner_map_meta->record = btf_record_dup(inner_map->record);
51 if (IS_ERR(inner_map_meta->record)) {
52 /* btf_record_dup returns NULL or valid pointer in case of
53 * invalid/empty/valid, but ERR_PTR in case of errors. During
54 * equality NULL or IS_ERR is equivalent.
55 */
56 ret = PTR_ERR(inner_map_meta->record);
57 goto free;
58 }
59 if (inner_map_meta->record) {
60 struct btf_field_offs *field_offs;
61 /* If btf_record is !IS_ERR_OR_NULL, then field_offs is always
62 * valid.
63 */
64 field_offs = kmemdup(inner_map->field_offs, sizeof(*inner_map->field_offs), GFP_KERNEL | __GFP_NOWARN);
65 if (!field_offs) {
66 ret = -ENOMEM;
67 goto free_rec;
68 }
69 inner_map_meta->field_offs = field_offs;
70 }
71 /* Note: We must use the same BTF, as we also used btf_record_dup above
72 * which relies on BTF being same for both maps, as some members like
73 * record->fields.list_head have pointers like value_rec pointing into
74 * inner_map->btf.
75 */
76 if (inner_map->btf) {
77 btf_get(inner_map->btf);
78 inner_map_meta->btf = inner_map->btf;
79 }
80
81 /* Misc members not needed in bpf_map_meta_equal() check. */
82 inner_map_meta->ops = inner_map->ops;
83 if (inner_map->ops == &array_map_ops) {
84 inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
85 container_of(inner_map_meta, struct bpf_array, map)->index_mask =
86 container_of(inner_map, struct bpf_array, map)->index_mask;
87 }
88
89 fdput(f);
90 return inner_map_meta;
91free_rec:
92 btf_record_free(inner_map_meta->record);
93free:
94 kfree(inner_map_meta);
95put:
96 fdput(f);
97 return ERR_PTR(ret);
98}
99
100void bpf_map_meta_free(struct bpf_map *map_meta)
101{
102 kfree(map_meta->field_offs);
103 bpf_map_free_record(map_meta);
104 btf_put(map_meta->btf);
105 kfree(map_meta);
106}
107
108bool bpf_map_meta_equal(const struct bpf_map *meta0,
109 const struct bpf_map *meta1)
110{
111 /* No need to compare ops because it is covered by map_type */
112 return meta0->map_type == meta1->map_type &&
113 meta0->key_size == meta1->key_size &&
114 meta0->value_size == meta1->value_size &&
115 meta0->map_flags == meta1->map_flags &&
116 btf_record_equal(meta0->record, meta1->record);
117}
118
119void *bpf_map_fd_get_ptr(struct bpf_map *map,
120 struct file *map_file /* not used */,
121 int ufd)
122{
123 struct bpf_map *inner_map, *inner_map_meta;
124 struct fd f;
125
126 f = fdget(ufd);
127 inner_map = __bpf_map_get(f);
128 if (IS_ERR(inner_map))
129 return inner_map;
130
131 inner_map_meta = map->inner_map_meta;
132 if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
133 bpf_map_inc(inner_map);
134 else
135 inner_map = ERR_PTR(-EINVAL);
136
137 fdput(f);
138 return inner_map;
139}
140
141void bpf_map_fd_put_ptr(void *ptr)
142{
143 /* ptr->ops->map_free() has to go through one
144 * rcu grace period by itself.
145 */
146 bpf_map_put(ptr);
147}
148
149u32 bpf_map_fd_sys_lookup_elem(void *ptr)
150{
151 return ((struct bpf_map *)ptr)->id;
152}
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 /* 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
66void bpf_map_meta_free(struct bpf_map *map_meta)
67{
68 kfree(map_meta);
69}
70
71bool 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
81void *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
103void 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
111u32 bpf_map_fd_sys_lookup_elem(void *ptr)
112{
113 return ((struct bpf_map *)ptr)->id;
114}