bpf: Explicitly size compatible_reg_types

Arrays with designated initializers have an implicit length of the highest
initialized value plus one. I used this to ensure that newly added entries
in enum bpf_reg_type get a NULL entry in compatible_reg_types.

This is difficult to understand since it requires knowledge of the
peculiarities of designated initializers. Use __BPF_ARG_TYPE_MAX to size
the array instead.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200923160156.80814-1-lmb@cloudflare.com
This commit is contained in:
Lorenz Bauer 2020-09-23 17:01:55 +01:00 committed by Alexei Starovoitov
parent a8a717963f
commit 0789e13bc3

View File

@ -4002,7 +4002,7 @@ static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_T
static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
static const struct bpf_reg_types *compatible_reg_types[] = {
static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
[ARG_PTR_TO_MAP_KEY] = &map_key_value_types,
[ARG_PTR_TO_MAP_VALUE] = &map_key_value_types,
[ARG_PTR_TO_UNINIT_MAP_VALUE] = &map_key_value_types,
@ -4025,7 +4025,6 @@ static const struct bpf_reg_types *compatible_reg_types[] = {
[ARG_PTR_TO_ALLOC_MEM_OR_NULL] = &alloc_mem_types,
[ARG_PTR_TO_INT] = &int_ptr_types,
[ARG_PTR_TO_LONG] = &int_ptr_types,
[__BPF_ARG_TYPE_MAX] = NULL,
};
static int check_reg_type(struct bpf_verifier_env *env, u32 regno,