netdev - Re: [PATCH net 3/3] openvswitch: Serialize nested ct actions if provided

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Date:	Thu, 15 Oct 2015 11:13:39 -0700
From:	Pravin Shelar <pshelar@...ira.com>
To:	Joe Stringer <joestringer@...ira.com>
Cc:	netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net 3/3] openvswitch: Serialize nested ct actions if provided

On Wed, Oct 14, 2015 at 11:10 AM, Joe Stringer <joestringer@...ira.com> wrote:
> If userspace provides a ct action with no nested mark or label, then the
> storage for these fields is zeroed. Later when actions are requested,
> such zeroed fields are serialized even though userspace didn't
> originally specify them. Fix the behaviour by ensuring that no action is
> serialized in this case, and reject actions where userspace attempts to
> set these fields with mask=0. This should make netlink marshalling
> consistent across deserialization/reserialization.
>
> Reported-by: Jarno Rajahalme <jrajahalme@...ira.com>
> Signed-off-by: Joe Stringer <joestringer@...ira.com>
> ---
>  net/openvswitch/conntrack.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> index 480dbb9095b7..ba29e6c2e0d4 100644
> --- a/net/openvswitch/conntrack.c
> +++ b/net/openvswitch/conntrack.c
> @@ -540,6 +540,16 @@ static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
>         return 0;
>  }
>
> +static bool label_zero(const struct ovs_key_ct_labels *labels)
> +{
> +       int i;
> +
> +       for (i = 0; i < sizeof(*labels); i++)
> +               if (labels->ct_labels[i])
> +                       return false;
> +       return true;
> +}
> +
There is already function called labels_nonzero(), This can be reused
for labels check.


>  static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
>         [OVS_CT_ATTR_COMMIT]    = { .minlen = 0, .maxlen = 0 },
>         [OVS_CT_ATTR_ZONE]      = { .minlen = sizeof(u16),
> @@ -589,6 +599,10 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
>                 case OVS_CT_ATTR_MARK: {
>                         struct md_mark *mark = nla_data(a);
>
> +                       if (!mark->mask) {
> +                               OVS_NLERR(log, "ct_mark mask cannot be 0");
> +                               return -EINVAL;
> +                       }
>                         info->mark = *mark;
>                         break;
>                 }
> @@ -597,6 +611,10 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
>                 case OVS_CT_ATTR_LABELS: {
>                         struct md_labels *labels = nla_data(a);
>
> +                       if (label_zero(&labels->mask)) {
> +                               OVS_NLERR(log, "ct_labels mask cannot be 0");
> +                               return -EINVAL;
> +                       }

After this flow install stage sanity check for labels, there is no
need for check in CONFIG_NF_CONNTRACK_LABELS action execution.
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