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 u32 inner_map_meta_size; 16 struct fd f; 17 18 f = fdget(inner_map_ufd); 19 inner_map = __bpf_map_get(f); 20 if (IS_ERR(inner_map)) 21 return inner_map; 22 23 /* prog_array->owner_prog_type and owner_jited 24 * is a runtime binding. Doing static check alone 25 * in the verifier is not enough. 26 */ 27 if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY || 28 inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || 29 inner_map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { 30 fdput(f); 31 return ERR_PTR(-ENOTSUPP); 32 } 33 34 /* Does not support >1 level map-in-map */ 35 if (inner_map->inner_map_meta) { 36 fdput(f); 37 return ERR_PTR(-EINVAL); 38 } 39 40 if (map_value_has_spin_lock(inner_map)) { 41 fdput(f); 42 return ERR_PTR(-ENOTSUPP); 43 } 44 45 inner_map_meta_size = sizeof(*inner_map_meta); 46 /* In some cases verifier needs to access beyond just base map. */ 47 if (inner_map->ops == &array_map_ops) 48 inner_map_meta_size = sizeof(struct bpf_array); 49 50 inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); 51 if (!inner_map_meta) { 52 fdput(f); 53 return ERR_PTR(-ENOMEM); 54 } 55 56 inner_map_meta->map_type = inner_map->map_type; 57 inner_map_meta->key_size = inner_map->key_size; 58 inner_map_meta->value_size = inner_map->value_size; 59 inner_map_meta->map_flags = inner_map->map_flags; 60 inner_map_meta->max_entries = inner_map->max_entries; 61 62 /* Misc members not needed in bpf_map_meta_equal() check. */ 63 inner_map_meta->ops = inner_map->ops; 64 if (inner_map->ops == &array_map_ops) { 65 inner_map_meta->unpriv_array = inner_map->unpriv_array; 66 container_of(inner_map_meta, struct bpf_array, map)->index_mask = 67 container_of(inner_map, struct bpf_array, map)->index_mask; 68 } 69 70 fdput(f); 71 return inner_map_meta; 72 } 73 74 void bpf_map_meta_free(struct bpf_map *map_meta) 75 { 76 kfree(map_meta); 77 } 78 79 bool bpf_map_meta_equal(const struct bpf_map *meta0, 80 const struct bpf_map *meta1) 81 { 82 /* No need to compare ops because it is covered by map_type */ 83 return meta0->map_type == meta1->map_type && 84 meta0->key_size == meta1->key_size && 85 meta0->value_size == meta1->value_size && 86 meta0->map_flags == meta1->map_flags && 87 meta0->max_entries == meta1->max_entries; 88 } 89 90 void *bpf_map_fd_get_ptr(struct bpf_map *map, 91 struct file *map_file /* not used */, 92 int ufd) 93 { 94 struct bpf_map *inner_map; 95 struct fd f; 96 97 f = fdget(ufd); 98 inner_map = __bpf_map_get(f); 99 if (IS_ERR(inner_map)) 100 return inner_map; 101 102 if (bpf_map_meta_equal(map->inner_map_meta, inner_map)) 103 inner_map = bpf_map_inc(inner_map, false); 104 else 105 inner_map = ERR_PTR(-EINVAL); 106 107 fdput(f); 108 return inner_map; 109 } 110 111 void bpf_map_fd_put_ptr(void *ptr) 112 { 113 /* ptr->ops->map_free() has to go through one 114 * rcu grace period by itself. 115 */ 116 bpf_map_put(ptr); 117 } 118 119 u32 bpf_map_fd_sys_lookup_elem(void *ptr) 120 { 121 return ((struct bpf_map *)ptr)->id; 122 } 123