// 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; } if (inner_map_meta->record) { struct btf_field_offs *field_offs; /* If btf_record is !IS_ERR_OR_NULL, then field_offs is always * valid. */ field_offs = kmemdup(inner_map->field_offs, sizeof(*inner_map->field_offs), GFP_KERNEL | __GFP_NOWARN); if (!field_offs) { ret = -ENOMEM; goto free_rec; } inner_map_meta->field_offs = field_offs; } /* 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) { inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; container_of(inner_map_meta, struct bpf_array, map)->index_mask = container_of(inner_map, struct bpf_array, map)->index_mask; } fdput(f); return inner_map_meta; free_rec: btf_record_free(inner_map_meta->record); free: kfree(inner_map_meta); put: fdput(f); return ERR_PTR(ret); } void bpf_map_meta_free(struct bpf_map *map_meta) { kfree(map_meta->field_offs); 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; }