1 /* Copyright (c) 2017 Facebook 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7 #include <linux/slab.h> 8 #include <linux/bpf.h> 9 10 #include "map_in_map.h" 11 12 struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) 13 { 14 struct bpf_map *inner_map, *inner_map_meta; 15 struct fd f; 16 17 f = fdget(inner_map_ufd); 18 inner_map = __bpf_map_get(f); 19 if (IS_ERR(inner_map)) 20 return inner_map; 21 22 /* prog_array->owner_prog_type and owner_jited 23 * is a runtime binding. Doing static check alone 24 * in the verifier is not enough. 25 */ 26 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY || 27 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE) { 28 fdput(f); 29 return ERR_PTR(-ENOTSUPP); 30 } 31 32 /* Does not support >1 level map-in-map */ 33 if (inner_map->inner_map_meta) { 34 fdput(f); 35 return ERR_PTR(-EINVAL); 36 } 37 38 inner_map_meta = kzalloc(sizeof(*inner_map_meta), GFP_USER); 39 if (!inner_map_meta) { 40 fdput(f); 41 return ERR_PTR(-ENOMEM); 42 } 43 44 inner_map_meta->map_type = inner_map->map_type; 45 inner_map_meta->key_size = inner_map->key_size; 46 inner_map_meta->value_size = inner_map->value_size; 47 inner_map_meta->map_flags = inner_map->map_flags; 48 inner_map_meta->ops = inner_map->ops; 49 inner_map_meta->max_entries = inner_map->max_entries; 50 51 fdput(f); 52 return inner_map_meta; 53 } 54 55 void bpf_map_meta_free(struct bpf_map *map_meta) 56 { 57 kfree(map_meta); 58 } 59 60 bool bpf_map_meta_equal(const struct bpf_map *meta0, 61 const struct bpf_map *meta1) 62 { 63 /* No need to compare ops because it is covered by map_type */ 64 return meta0->map_type == meta1->map_type && 65 meta0->key_size == meta1->key_size && 66 meta0->value_size == meta1->value_size && 67 meta0->map_flags == meta1->map_flags && 68 meta0->max_entries == meta1->max_entries; 69 } 70 71 void *bpf_map_fd_get_ptr(struct bpf_map *map, 72 struct file *map_file /* not used */, 73 int ufd) 74 { 75 struct bpf_map *inner_map; 76 struct fd f; 77 78 f = fdget(ufd); 79 inner_map = __bpf_map_get(f); 80 if (IS_ERR(inner_map)) 81 return inner_map; 82 83 if (bpf_map_meta_equal(map->inner_map_meta, inner_map)) 84 inner_map = bpf_map_inc(inner_map, false); 85 else 86 inner_map = ERR_PTR(-EINVAL); 87 88 fdput(f); 89 return inner_map; 90 } 91 92 void bpf_map_fd_put_ptr(void *ptr) 93 { 94 /* ptr->ops->map_free() has to go through one 95 * rcu grace period by itself. 96 */ 97 bpf_map_put(ptr); 98 } 99 100 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 101 { 102 return ((struct bpf_map *)ptr)->id; 103 } 104