From 5f300e8004cb80182a24c0fa488218a4a43e6aac Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 26 Jul 2018 09:57:59 -0700 Subject: bpf: btf: Use exact btf value_size match in map_check_btf() The current map_check_btf() in BPF_MAP_TYPE_ARRAY rejects '> map->value_size' to ensure map_seq_show_elem() will not access things beyond an array element. Yonghong suggested that using '!=' is a more correct check. The 8 bytes round_up on value_size is stored in array->elem_size. Hence, using '!=' on map->value_size is a proper check. This patch also adds new tests to check the btf array key type and value type. Two of these new tests verify the btf's value_size (the change in this patch). It also fixes two existing tests that wrongly encoded a btf's type size (pprint_test) and the value_type_id (in one of the raw_tests[]). However, that do not affect these two BTF verification tests before or after this test changes. These two tests mainly failed at array creation time after this patch. Fixes: a26ca7c982cb ("bpf: btf: Add pretty print support to the basic arraymap") Suggested-by: Yonghong Song Acked-by: Yonghong Song Signed-off-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann --- kernel/bpf/arraymap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 544e58f5f642..2aa55d030c77 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -378,7 +378,7 @@ static int array_map_check_btf(const struct bpf_map *map, const struct btf *btf, return -EINVAL; value_type = btf_type_id_size(btf, &btf_value_id, &value_size); - if (!value_type || value_size > map->value_size) + if (!value_type || value_size != map->value_size) return -EINVAL; return 0; -- cgit v1.2.3