Re: [PATCH] hw/net/rocker: avoid NULL pointer dereference in of_dpa_cmd_add_l2_flood

[Mauro Matteo Cascella]

On Fri, Jun 24, 2022 at 4:40 PM Mauro Matteo Cascella
<mcascell@redhat.com> wrote:
>
> rocker_tlv_parse_nested could return early because of no group ids in
> the group_tlvs. In such case tlvs is NULL; tlvs[i + 1] in the next
> for-loop will deref the NULL pointer.

Someone somehow reserved a new CVE for this bug, published a few days
ago here: https://nvd.nist.gov/vuln/detail/CVE-2022-36648.

Not only is this not CVE worthy (rocker code does not fall under the
KVM virtualization use case [1]) but what's most concerning is that it
got a CVSS score of 10 :/

I'm going to dispute this CVE. Hopefully, it will be rejected soon. In
any case, can we get this patch merged?

[1] https://www.qemu.org/docs/master/system/security.html

Thanks,

> Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
> Reported-by: <arayz_w@icloud.com>
> ---
>  hw/net/rocker/rocker_of_dpa.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/hw/net/rocker/rocker_of_dpa.c b/hw/net/rocker/rocker_of_dpa.c
> index b3b8c5bb6d..1611b79227 100644
> --- a/hw/net/rocker/rocker_of_dpa.c
> +++ b/hw/net/rocker/rocker_of_dpa.c
> @@ -2039,6 +2039,11 @@ static int of_dpa_cmd_add_l2_flood(OfDpa *of_dpa, 
> OfDpaGroup *group,
>      rocker_tlv_parse_nested(tlvs, group->l2_flood.group_count,
>                              group_tlvs[ROCKER_TLV_OF_DPA_GROUP_IDS]);
>
> +    if (!tlvs) {
> +        err = -ROCKER_EINVAL;
> +        goto err_out;
> +    }
> +
>      for (i = 0; i < group->l2_flood.group_count; i++) {
>          group->l2_flood.group_ids[i] = rocker_tlv_get_le32(tlvs[i + 1]);
>      }
> --
> 2.35.3
>

--
Mauro Matteo Cascella
Red Hat Product Security
PGP-Key ID: BB3410B0