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 inner_map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { 29 fdput(f); 30 return ERR_PTR(-ENOTSUPP); 31 } 32 33 /* Does not support >1 level map-in-map */ 34 if (inner_map->inner_map_meta) { 35 fdput(f); 36 return ERR_PTR(-EINVAL); 37 } 38 39 inner_map_meta = kzalloc(sizeof(*inner_map_meta), GFP_USER); 40 if (!inner_map_meta) { 41 fdput(f); 42 return ERR_PTR(-ENOMEM); 43 } 44 45 inner_map_meta->map_type = inner_map->map_type; 46 inner_map_meta->key_size = inner_map->key_size; 47 inner_map_meta->value_size = inner_map->value_size; 48 inner_map_meta->map_flags = inner_map->map_flags; 49 inner_map_meta->ops = inner_map->ops; 50 inner_map_meta->max_entries = inner_map->max_entries; 51 52 fdput(f); 53 return inner_map_meta; 54 } 55 56 void bpf_map_meta_free(struct bpf_map *map_meta) 57 { 58 kfree(map_meta); 59 } 60 61 bool bpf_map_meta_equal(const struct bpf_map *meta0, 62 const struct bpf_map *meta1) 63 { 64 /* No need to compare ops because it is covered by map_type */ 65 return meta0->map_type == meta1->map_type && 66 meta0->key_size == meta1->key_size && 67 meta0->value_size == meta1->value_size && 68 meta0->map_flags == meta1->map_flags && 69 meta0->max_entries == meta1->max_entries; 70 } 71 72 void *bpf_map_fd_get_ptr(struct bpf_map *map, 73 struct file *map_file /* not used */, 74 int ufd) 75 { 76 struct bpf_map *inner_map; 77 struct fd f; 78 79 f = fdget(ufd); 80 inner_map = __bpf_map_get(f); 81 if (IS_ERR(inner_map)) 82 return inner_map; 83 84 if (bpf_map_meta_equal(map->inner_map_meta, inner_map)) 85 inner_map = bpf_map_inc(inner_map, false); 86 else 87 inner_map = ERR_PTR(-EINVAL); 88 89 fdput(f); 90 return inner_map; 91 } 92 93 void bpf_map_fd_put_ptr(void *ptr) 94 { 95 /* ptr->ops->map_free() has to go through one 96 * rcu grace period by itself. 97 */ 98 bpf_map_put(ptr); 99 } 100 101 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 102 { 103 return ((struct bpf_map *)ptr)->id; 104 } 105