1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#include <linux/slab.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include "map_in_map.h"
struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
{
struct bpf_map *inner_map, *inner_map_meta;
u32 inner_map_meta_size;
struct fd f;
f = fdget(inner_map_ufd);
inner_map = __bpf_map_get(f);
if (IS_ERR(inner_map))
return inner_map;
/* Does not support >1 level map-in-map */
if (inner_map->inner_map_meta) {
fdput(f);
return ERR_PTR(-EINVAL);
}
if (!inner_map->ops->map_meta_equal) {
fdput(f);
return ERR_PTR(-ENOTSUPP);
}
if (map_value_has_spin_lock(inner_map)) {
fdput(f);
return ERR_PTR(-ENOTSUPP);
}
inner_map_meta_size = sizeof(*inner_map_meta);
/* In some cases verifier needs to access beyond just base map. */
if (inner_map->ops == &array_map_ops)
inner_map_meta_size = sizeof(struct bpf_array);
inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
if (!inner_map_meta) {
fdput(f);
return ERR_PTR(-ENOMEM);
}
inner_map_meta->map_type = inner_map->map_type;
inner_map_meta->key_size = inner_map->key_size;
inner_map_meta->value_size = inner_map->value_size;
inner_map_meta->map_flags = inner_map->map_flags;
inner_map_meta->max_entries = inner_map->max_entries;
inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
inner_map_meta->timer_off = inner_map->timer_off;
inner_map_meta->kptr_off_tab = bpf_map_copy_kptr_off_tab(inner_map);
if (inner_map->btf) {
btf_get(inner_map->btf);
inner_map_meta->btf = inner_map->btf;
}
/* Misc members not needed in bpf_map_meta_equal() check. */
inner_map_meta->ops = inner_map->ops;
if (inner_map->ops == &array_map_ops) {
struct bpf_array *inner_array_meta =
container_of(inner_map_meta, struct bpf_array, map);
struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map);
inner_array_meta->index_mask = inner_array->index_mask;
inner_array_meta->elem_size = inner_array->elem_size;
inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
}
fdput(f);
return inner_map_meta;
}
void bpf_map_meta_free(struct bpf_map *map_meta)
{
bpf_map_free_kptr_off_tab(map_meta);
btf_put(map_meta->btf);
kfree(map_meta);
}
bool bpf_map_meta_equal(const struct bpf_map *meta0,
const struct bpf_map *meta1)
{
/* No need to compare ops because it is covered by map_type */
return meta0->map_type == meta1->map_type &&
meta0->key_size == meta1->key_size &&
meta0->value_size == meta1->value_size &&
meta0->timer_off == meta1->timer_off &&
meta0->map_flags == meta1->map_flags &&
bpf_map_equal_kptr_off_tab(meta0, meta1);
}
void *bpf_map_fd_get_ptr(struct bpf_map *map,
struct file *map_file /* not used */,
int ufd)
{
struct bpf_map *inner_map, *inner_map_meta;
struct fd f;
f = fdget(ufd);
inner_map = __bpf_map_get(f);
if (IS_ERR(inner_map))
return inner_map;
inner_map_meta = map->inner_map_meta;
if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
bpf_map_inc(inner_map);
else
inner_map = ERR_PTR(-EINVAL);
fdput(f);
return inner_map;
}
void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer)
{
struct bpf_map *inner_map = ptr;
/* The inner map may still be used by both non-sleepable and sleepable
* bpf program, so free it after one RCU grace period and one tasks
* trace RCU grace period.
*/
if (need_defer)
WRITE_ONCE(inner_map->free_after_mult_rcu_gp, true);
bpf_map_put(inner_map);
}
u32 bpf_map_fd_sys_lookup_elem(void *ptr)
{
return ((struct bpf_map *)ptr)->id;
}
|
