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