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