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 /* prog_array->aux->{type,jited} is a runtime binding. 21 * Doing static check alone in the verifier is not enough. 22 */ 23 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY || 24 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || 25 inner_map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { 26 fdput(f); 27 return ERR_PTR(-ENOTSUPP); 28 } 29 30 /* Does not support >1 level map-in-map */ 31 if (inner_map->inner_map_meta) { 32 fdput(f); 33 return ERR_PTR(-EINVAL); 34 } 35 36 if (map_value_has_spin_lock(inner_map)) { 37 fdput(f); 38 return ERR_PTR(-ENOTSUPP); 39 } 40 41 inner_map_meta_size = sizeof(*inner_map_meta); 42 /* In some cases verifier needs to access beyond just base map. */ 43 if (inner_map->ops == &array_map_ops) 44 inner_map_meta_size = sizeof(struct bpf_array); 45 46 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); 47 if (!inner_map_meta) { 48 fdput(f); 49 return ERR_PTR(-ENOMEM); 50 } 51 52 inner_map_meta->map_type = inner_map->map_type; 53 inner_map_meta->key_size = inner_map->key_size; 54 inner_map_meta->value_size = inner_map->value_size; 55 inner_map_meta->map_flags = inner_map->map_flags; 56 inner_map_meta->max_entries = inner_map->max_entries; 57 inner_map_meta->spin_lock_off = inner_map->spin_lock_off; 58 59 /* Misc members not needed in bpf_map_meta_equal() check. */ 60 inner_map_meta->ops = inner_map->ops; 61 if (inner_map->ops == &array_map_ops) { 62 inner_map_meta->unpriv_array = inner_map->unpriv_array; 63 container_of(inner_map_meta, struct bpf_array, map)->index_mask = 64 container_of(inner_map, struct bpf_array, map)->index_mask; 65 } 66 67 fdput(f); 68 return inner_map_meta; 69 } 70 71 void bpf_map_meta_free(struct bpf_map *map_meta) 72 { 73 kfree(map_meta); 74 } 75 76 bool bpf_map_meta_equal(const struct bpf_map *meta0, 77 const struct bpf_map *meta1) 78 { 79 /* No need to compare ops because it is covered by map_type */ 80 return meta0->map_type == meta1->map_type && 81 meta0->key_size == meta1->key_size && 82 meta0->value_size == meta1->value_size && 83 meta0->map_flags == meta1->map_flags && 84 meta0->max_entries == meta1->max_entries; 85 } 86 87 void *bpf_map_fd_get_ptr(struct bpf_map *map, 88 struct file *map_file /* not used */, 89 int ufd) 90 { 91 struct bpf_map *inner_map; 92 struct fd f; 93 94 f = fdget(ufd); 95 inner_map = __bpf_map_get(f); 96 if (IS_ERR(inner_map)) 97 return inner_map; 98 99 if (bpf_map_meta_equal(map->inner_map_meta, inner_map)) 100 bpf_map_inc(inner_map); 101 else 102 inner_map = ERR_PTR(-EINVAL); 103 104 fdput(f); 105 return inner_map; 106 } 107 108 void bpf_map_fd_put_ptr(void *ptr) 109 { 110 /* ptr->ops->map_free() has to go through one 111 * rcu grace period by itself. 112 */ 113 bpf_map_put(ptr); 114 } 115 116 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 117 { 118 return ((struct bpf_map *)ptr)->id; 119 } 120