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 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 inner_map_meta->record = btf_record_dup(inner_map->record); 56 if (IS_ERR(inner_map_meta->record)) { 57 /* btf_record_dup returns NULL or valid pointer in case of 58 * invalid/empty/valid, but ERR_PTR in case of errors. During 59 * equality NULL or IS_ERR is equivalent. 60 */ 61 fdput(f); 62 return ERR_CAST(inner_map_meta->record); 63 } 64 if (inner_map->btf) { 65 btf_get(inner_map->btf); 66 inner_map_meta->btf = inner_map->btf; 67 } 68 69 /* Misc members not needed in bpf_map_meta_equal() check. */ 70 inner_map_meta->ops = inner_map->ops; 71 if (inner_map->ops == &array_map_ops) { 72 inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; 73 container_of(inner_map_meta, struct bpf_array, map)->index_mask = 74 container_of(inner_map, struct bpf_array, map)->index_mask; 75 } 76 77 fdput(f); 78 return inner_map_meta; 79 } 80 81 void bpf_map_meta_free(struct bpf_map *map_meta) 82 { 83 bpf_map_free_record(map_meta); 84 btf_put(map_meta->btf); 85 kfree(map_meta); 86 } 87 88 bool bpf_map_meta_equal(const struct bpf_map *meta0, 89 const struct bpf_map *meta1) 90 { 91 /* No need to compare ops because it is covered by map_type */ 92 return meta0->map_type == meta1->map_type && 93 meta0->key_size == meta1->key_size && 94 meta0->value_size == meta1->value_size && 95 meta0->timer_off == meta1->timer_off && 96 meta0->map_flags == meta1->map_flags && 97 btf_record_equal(meta0->record, meta1->record); 98 } 99 100 void *bpf_map_fd_get_ptr(struct bpf_map *map, 101 struct file *map_file /* not used */, 102 int ufd) 103 { 104 struct bpf_map *inner_map, *inner_map_meta; 105 struct fd f; 106 107 f = fdget(ufd); 108 inner_map = __bpf_map_get(f); 109 if (IS_ERR(inner_map)) 110 return inner_map; 111 112 inner_map_meta = map->inner_map_meta; 113 if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map)) 114 bpf_map_inc(inner_map); 115 else 116 inner_map = ERR_PTR(-EINVAL); 117 118 fdput(f); 119 return inner_map; 120 } 121 122 void bpf_map_fd_put_ptr(void *ptr) 123 { 124 /* ptr->ops->map_free() has to go through one 125 * rcu grace period by itself. 126 */ 127 bpf_map_put(ptr); 128 } 129 130 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 131 { 132 return ((struct bpf_map *)ptr)->id; 133 } 134