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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | // 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; int ret; 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) { ret = -EINVAL; goto put; } if (!inner_map->ops->map_meta_equal) { ret = -ENOTSUPP; goto put; } 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) { ret = -ENOMEM; goto put; } 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->record = btf_record_dup(inner_map->record); if (IS_ERR(inner_map_meta->record)) { /* btf_record_dup returns NULL or valid pointer in case of * invalid/empty/valid, but ERR_PTR in case of errors. During * equality NULL or IS_ERR is equivalent. */ ret = PTR_ERR(inner_map_meta->record); goto free; } /* Note: We must use the same BTF, as we also used btf_record_dup above * which relies on BTF being same for both maps, as some members like * record->fields.list_head have pointers like value_rec pointing into * inner_map->btf. */ 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; free: kfree(inner_map_meta); put: fdput(f); return ERR_PTR(ret); } void bpf_map_meta_free(struct bpf_map *map_meta) { bpf_map_free_record(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->map_flags == meta1->map_flags && btf_record_equal(meta0->record, meta1->record); } 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(void *ptr) { /* ptr->ops->map_free() has to go through one * rcu grace period by itself. */ bpf_map_put(ptr); } u32 bpf_map_fd_sys_lookup_elem(void *ptr) { return ((struct bpf_map *)ptr)->id; } |