Commit 134fede4 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Daniel Borkmann
Browse files

bpf: Relax max_entries check for most of the inner map types 



Most of the maps do not use max_entries during verification time.
Thus, those map_meta_equal() do not need to enforce max_entries
when it is inserted as an inner map during runtime.  The max_entries
check is removed from the default implementation bpf_map_meta_equal().

The prog_array_map and xsk_map are exception.  Its map_gen_lookup
uses max_entries to generate inline lookup code.  Thus, they will
implement its own map_meta_equal() to enforce max_entries.
Since there are only two cases now, the max_entries check
is not refactored and stays in its own .c file.

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200828011813.1970516-1-kafai@fb.com
parent f4d05259

kernel/bpf/arraymap.c

+8 −1
Original line number Diff line number Diff line
@@ -487,6 +487,13 @@ static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) 
				   vma->vm_pgoff + pgoff);

}



static bool array_map_meta_equal(const struct bpf_map *meta0,

				 const struct bpf_map *meta1)

{

	return meta0->max_entries == meta1->max_entries &&

		bpf_map_meta_equal(meta0, meta1);

}



struct bpf_iter_seq_array_map_info {

	struct bpf_map *map;

	void *percpu_value_buf;
@@ -625,7 +632,7 @@ static const struct bpf_iter_seq_info iter_seq_info = { 


static int array_map_btf_id;

const struct bpf_map_ops array_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_meta_equal = array_map_meta_equal,

	.map_alloc_check = array_map_alloc_check,

	.map_alloc = array_map_alloc,

	.map_free = array_map_free,

kernel/bpf/map_in_map.c

+1 −2
Original line number Diff line number Diff line
@@ -75,8 +75,7 @@ bool bpf_map_meta_equal(const struct bpf_map *meta0, 
	return meta0->map_type == meta1->map_type &&

		meta0->key_size == meta1->key_size &&

		meta0->value_size == meta1->value_size &&

		meta0->map_flags == meta1->map_flags &&

		meta0->max_entries == meta1->max_entries;

		meta0->map_flags == meta1->map_flags;

}



void *bpf_map_fd_get_ptr(struct bpf_map *map,

net/xdp/xskmap.c

+8 −1
Original line number Diff line number Diff line
@@ -254,9 +254,16 @@ void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, 
	spin_unlock_bh(&map->lock);

}



static bool xsk_map_meta_equal(const struct bpf_map *meta0,

			       const struct bpf_map *meta1)

{

	return meta0->max_entries == meta1->max_entries &&

		bpf_map_meta_equal(meta0, meta1);

}



static int xsk_map_btf_id;

const struct bpf_map_ops xsk_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,

	.map_meta_equal = xsk_map_meta_equal,

	.map_alloc = xsk_map_alloc,

	.map_free = xsk_map_free,

	.map_get_next_key = xsk_map_get_next_key,

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