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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Fri, 4 Feb 2022 11:32:28 -0800
Message-ID: <CAADnVQJy_ksv9hYDhjGvxzMQipa7Fw4DGrAajhSLZKZcPNBf8g@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3 1/2] bpf: limit bpf_core_types_are_compat() recursion
To:     Matteo Croce <mcroce@linux.microsoft.com>
Cc:     bpf <bpf@vger.kernel.org>, Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, Feb 3, 2022 at 4:55 PM Matteo Croce <mcroce@linux.microsoft.com> 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.