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 7 #include "map_in_map.h" 8 9 struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) 10 { 11 struct bpf_map *inner_map, *inner_map_meta; 12 u32 inner_map_meta_size; 13 struct fd f; 14 15 f = fdget(inner_map_ufd); 16 inner_map = __bpf_map_get(f); 17 if (IS_ERR(inner_map)) 18 return inner_map; 19 20 /* Does not support >1 level map-in-map */ 21 if (inner_map->inner_map_meta) { 22 fdput(f); 23 return ERR_PTR(-EINVAL); 24 } 25 26 if (!inner_map->ops->map_meta_equal) { 27 fdput(f); 28 return ERR_PTR(-ENOTSUPP); 29 } 30 31 if (map_value_has_spin_lock(inner_map)) { 32 fdput(f); 33 return ERR_PTR(-ENOTSUPP); 34 } 35 36 inner_map_meta_size = sizeof(*inner_map_meta); 37 /* In some cases verifier needs to access beyond just base map. */ 38 if (inner_map->ops == &array_map_ops) 39 inner_map_meta_size = sizeof(struct bpf_array); 40 41 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); 42 if (!inner_map_meta) { 43 fdput(f); 44 return ERR_PTR(-ENOMEM); 45 } 46 47 inner_map_meta->map_type = inner_map->map_type; 48 inner_map_meta->key_size = inner_map->key_size; 49 inner_map_meta->value_size = inner_map->value_size; 50 inner_map_meta->map_flags = inner_map->map_flags; 51 inner_map_meta->max_entries = inner_map->max_entries; 52 inner_map_meta->spin_lock_off = inner_map->spin_lock_off; 53 54 /* Misc members not needed in bpf_map_meta_equal() check. */ 55 inner_map_meta->ops = inner_map->ops; 56 if (inner_map->ops == &array_map_ops) { 57 inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; 58 container_of(inner_map_meta, struct bpf_array, map)->index_mask = 59 container_of(inner_map, struct bpf_array, map)->index_mask; 60 } 61 62 fdput(f); 63 return inner_map_meta; 64 } 65 66 void bpf_map_meta_free(struct bpf_map *map_meta) 67 { 68 kfree(map_meta); 69 } 70 71 bool bpf_map_meta_equal(const struct bpf_map *meta0, 72 const struct bpf_map *meta1) 73 { 74 /* No need to compare ops because it is covered by map_type */ 75 return meta0->map_type == meta1->map_type && 76 meta0->key_size == meta1->key_size && 77 meta0->value_size == meta1->value_size && 78 meta0->map_flags == meta1->map_flags; 79 } 80 81 void *bpf_map_fd_get_ptr(struct bpf_map *map, 82 struct file *map_file /* not used */, 83 int ufd) 84 { 85 struct bpf_map *inner_map, *inner_map_meta; 86 struct fd f; 87 88 f = fdget(ufd); 89 inner_map = __bpf_map_get(f); 90 if (IS_ERR(inner_map)) 91 return inner_map; 92 93 inner_map_meta = map->inner_map_meta; 94 if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map)) 95 bpf_map_inc(inner_map); 96 else 97 inner_map = ERR_PTR(-EINVAL); 98 99 fdput(f); 100 return inner_map; 101 } 102 103 void bpf_map_fd_put_ptr(void *ptr) 104 { 105 /* ptr->ops->map_free() has to go through one 106 * rcu grace period by itself. 107 */ 108 bpf_map_put(ptr); 109 } 110 111 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 112 { 113 return ((struct bpf_map *)ptr)->id; 114 } 115