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->owner_prog_type and owner_jited 21 * is a runtime binding. Doing static check alone 22 * in the verifier is not enough. 23 */ 24 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY || 25 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || 26 inner_map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { 27 fdput(f); 28 return ERR_PTR(-ENOTSUPP); 29 } 30 31 /* Does not support >1 level map-in-map */ 32 if (inner_map->inner_map_meta) { 33 fdput(f); 34 return ERR_PTR(-EINVAL); 35 } 36 37 if (map_value_has_spin_lock(inner_map)) { 38 fdput(f); 39 return ERR_PTR(-ENOTSUPP); 40 } 41 42 inner_map_meta_size = sizeof(*inner_map_meta); 43 /* In some cases verifier needs to access beyond just base map. */ 44 if (inner_map->ops == &array_map_ops) 45 inner_map_meta_size = sizeof(struct bpf_array); 46 47 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); 48 if (!inner_map_meta) { 49 fdput(f); 50 return ERR_PTR(-ENOMEM); 51 } 52 53 inner_map_meta->map_type = inner_map->map_type; 54 inner_map_meta->key_size = inner_map->key_size; 55 inner_map_meta->value_size = inner_map->value_size; 56 inner_map_meta->map_flags = inner_map->map_flags; 57 inner_map_meta->max_entries = inner_map->max_entries; 58 inner_map_meta->spin_lock_off = inner_map->spin_lock_off; 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->unpriv_array = inner_map->unpriv_array; 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 kfree(map_meta); 75 } 76 77 bool bpf_map_meta_equal(const struct bpf_map *meta0, 78 const struct bpf_map *meta1) 79 { 80 /* No need to compare ops because it is covered by map_type */ 81 return meta0->map_type == meta1->map_type && 82 meta0->key_size == meta1->key_size && 83 meta0->value_size == meta1->value_size && 84 meta0->map_flags == meta1->map_flags && 85 meta0->max_entries == meta1->max_entries; 86 } 87 88 void *bpf_map_fd_get_ptr(struct bpf_map *map, 89 struct file *map_file /* not used */, 90 int ufd) 91 { 92 struct bpf_map *inner_map; 93 struct fd f; 94 95 f = fdget(ufd); 96 inner_map = __bpf_map_get(f); 97 if (IS_ERR(inner_map)) 98 return inner_map; 99 100 if (bpf_map_meta_equal(map->inner_map_meta, inner_map)) 101 inner_map = bpf_map_inc(inner_map, false); 102 else 103 inner_map = ERR_PTR(-EINVAL); 104 105 fdput(f); 106 return inner_map; 107 } 108 109 void bpf_map_fd_put_ptr(void *ptr) 110 { 111 /* ptr->ops->map_free() has to go through one 112 * rcu grace period by itself. 113 */ 114 bpf_map_put(ptr); 115 } 116 117 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 118 { 119 return ((struct bpf_map *)ptr)->id; 120 } 121