Re: [PATCH bpf-next v3 1/2] bpf: limit bpf_core_types_are_compat() recursion

From: Alexei Starovoitov
Date: Fri Feb 04 2022 - 14:32:42 EST


On Thu, Feb 3, 2022 at 4:55 PM Matteo Croce <mcroce@xxxxxxxxxxxxxxxxxxx> wrote:
> +
> + for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
> + if (level <= 1)
> + return -EINVAL;

<= 1 is not correct, since it makes
MAX_TYPES_ARE_COMPAT_DEPTH 2
misleading.
With <= 1 the recursion depth is just 1.
So I've changed to to <=0 to make the actual depth of 2.