cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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map_in_map.c (3189B)

      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#include <linux/btf.h>
      7
      8#include "map_in_map.h"
      9
     10struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
     11{
     12	struct bpf_map *inner_map, *inner_map_meta;
     13	u32 inner_map_meta_size;
     14	struct fd f;
     15
     16	f = fdget(inner_map_ufd);
     17	inner_map = __bpf_map_get(f);
     18	if (IS_ERR(inner_map))
     19		return inner_map;
     20
     21	/* Does not support >1 level map-in-map */
     22	if (inner_map->inner_map_meta) {
     23		fdput(f);
     24		return ERR_PTR(-EINVAL);
     25	}
     26
     27	if (!inner_map->ops->map_meta_equal) {
     28		fdput(f);
     29		return ERR_PTR(-ENOTSUPP);
     30	}
     31
     32	if (map_value_has_spin_lock(inner_map)) {
     33		fdput(f);
     34		return ERR_PTR(-ENOTSUPP);
     35	}
     36
     37	inner_map_meta_size = sizeof(*inner_map_meta);
     38	/* In some cases verifier needs to access beyond just base map. */
     39	if (inner_map->ops == &array_map_ops)
     40		inner_map_meta_size = sizeof(struct bpf_array);
     41
     42	inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
     43	if (!inner_map_meta) {
     44		fdput(f);
     45		return ERR_PTR(-ENOMEM);
     46	}
     47
     48	inner_map_meta->map_type = inner_map->map_type;
     49	inner_map_meta->key_size = inner_map->key_size;
     50	inner_map_meta->value_size = inner_map->value_size;
     51	inner_map_meta->map_flags = inner_map->map_flags;
     52	inner_map_meta->max_entries = inner_map->max_entries;
     53	inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
     54	inner_map_meta->timer_off = inner_map->timer_off;
     55	inner_map_meta->kptr_off_tab = bpf_map_copy_kptr_off_tab(inner_map);
     56	if (inner_map->btf) {
     57		btf_get(inner_map->btf);
     58		inner_map_meta->btf = inner_map->btf;
     59	}
     60
     61	/* Misc members not needed in bpf_map_meta_equal() check. */
     62	inner_map_meta->ops = inner_map->ops;
     63	if (inner_map->ops == &array_map_ops) {
     64		inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
     65		container_of(inner_map_meta, struct bpf_array, map)->index_mask =
     66		     container_of(inner_map, struct bpf_array, map)->index_mask;
     67	}
     68
     69	fdput(f);
     70	return inner_map_meta;
     71}
     72
     73void bpf_map_meta_free(struct bpf_map *map_meta)
     74{
     75	bpf_map_free_kptr_off_tab(map_meta);
     76	btf_put(map_meta->btf);
     77	kfree(map_meta);
     78}
     79
     80bool bpf_map_meta_equal(const struct bpf_map *meta0,
     81			const struct bpf_map *meta1)
     82{
     83	/* No need to compare ops because it is covered by map_type */
     84	return meta0->map_type == meta1->map_type &&
     85		meta0->key_size == meta1->key_size &&
     86		meta0->value_size == meta1->value_size &&
     87		meta0->timer_off == meta1->timer_off &&
     88		meta0->map_flags == meta1->map_flags &&
     89		bpf_map_equal_kptr_off_tab(meta0, meta1);
     90}
     91
     92void *bpf_map_fd_get_ptr(struct bpf_map *map,
     93			 struct file *map_file /* not used */,
     94			 int ufd)
     95{
     96	struct bpf_map *inner_map, *inner_map_meta;
     97	struct fd f;
     98
     99	f = fdget(ufd);
    100	inner_map = __bpf_map_get(f);
    101	if (IS_ERR(inner_map))
    102		return inner_map;
    103
    104	inner_map_meta = map->inner_map_meta;
    105	if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
    106		bpf_map_inc(inner_map);
    107	else
    108		inner_map = ERR_PTR(-EINVAL);
    109
    110	fdput(f);
    111	return inner_map;
    112}
    113
    114void bpf_map_fd_put_ptr(void *ptr)
    115{
    116	/* ptr->ops->map_free() has to go through one
    117	 * rcu grace period by itself.
    118	 */
    119	bpf_map_put(ptr);
    120}
    121
    122u32 bpf_map_fd_sys_lookup_elem(void *ptr)
    123{
    124	return ((struct bpf_map *)ptr)->id;
    125}