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
  9struct 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
 72void bpf_map_meta_free(struct bpf_map *map_meta)
 73{
 74	kfree(map_meta);
 75}
 76
 77bool 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
 88void *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
109void 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
117u32 bpf_map_fd_sys_lookup_elem(void *ptr)
118{
119	return ((struct bpf_map *)ptr)->id;
120}