2024-04-18, 18:17:16 -0700, Rahul Rameshbabu wrote:
> diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
> index 0206b84284ab..679302ef1cd9 100644
> --- a/drivers/net/macsec.c
> +++ b/drivers/net/macsec.c
> @@ -991,6 +991,19 @@ static struct macsec_rx_sc *find_rx_sc_rtnl(struct macsec_secy *secy, sci_t sci)
> return NULL;
> }
>
> +static __u8 macsec_offload_pkt_type(const u8 *h_dest, const u8 *ndev_broadcast)
> +
nit: empty line shouldn't be here
> +{
> + if (is_multicast_ether_addr_64bits(h_dest)) {
> + if (ether_addr_equal_64bits(h_dest, ndev_broadcast))
> + return PACKET_BROADCAST;
> + else
> + return PACKET_MULTICAST;
> + }
> +
> + return PACKET_HOST;
> +}
> +
> static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
> {
> /* Deliver to the uncontrolled port by default */
> @@ -999,10 +1012,12 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
> struct metadata_dst *md_dst;
> struct macsec_rxh_data *rxd;
> struct macsec_dev *macsec;
> + bool is_macsec_md_dst;
>
> rcu_read_lock();
> rxd = macsec_data_rcu(skb->dev);
> md_dst = skb_metadata_dst(skb);
> + is_macsec_md_dst = md_dst && md_dst->type == METADATA_MACSEC;
>
> list_for_each_entry_rcu(macsec, &rxd->secys, secys) {
> struct sk_buff *nskb;
> @@ -1014,13 +1029,40 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
> */
> if (macsec_is_offloaded(macsec) && netif_running(ndev)) {
> struct macsec_rx_sc *rx_sc = NULL;
Please move this into the "if (is_macsec_md_dst)" block below, since
it's no longer used outside.
> + const struct macsec_ops *ops;
>
> - if (md_dst && md_dst->type == METADATA_MACSEC)
> - rx_sc = find_rx_sc(&macsec->secy, md_dst->u.macsec_info.sci);
> + ops = macsec_get_ops(macsec, NULL);
>
> - if (md_dst && md_dst->type == METADATA_MACSEC && !rx_sc)
> + if (ops->rx_uses_md_dst && !is_macsec_md_dst)
> continue;
>
> + if (is_macsec_md_dst) {
> + /* All drivers that implement MACsec offload
> + * support using skb metadata destinations must
> + * indicate that they do so.
> + */
> + DEBUG_NET_WARN_ON_ONCE(!ops->rx_uses_md_dst);
> + rx_sc = find_rx_sc(&macsec->secy, md_dst->u.macsec_info.sci);
> + if (!rx_sc)
> + continue;
> + /* device indicated macsec offload occurred */
> + skb->dev = ndev;
> + skb->pkt_type = macsec_offload_pkt_type(
> + hdr->h_dest, ndev->broadcast);
> + ret = RX_HANDLER_ANOTHER;
> + goto out;
> + }
> +
> + /* This datapath is insecure because it is unable to
> + * enforce isolation of broadcast/multicast traffic and
> + * unicast traffic with promiscuous mode on the macsec
> + * netdev. Since the core stack has no mechanism to
> + * check that the hardware did indeed receive MACsec
> + * traffic, it is possible that the response handling
> + * done by the MACsec port was to a plaintext packet.
> + * This violates the MACsec protocol standard.
> + */
> + DEBUG_NET_WARN_ON_ONCE(true);
If you insist on this warning (and I'm not convinced it's useful,
since if the HW is already built and cannot inform the driver, there's
nothing the driver implementer can do), I would move it somewhere into
the config path. macsec_update_offload would be a better location for
this kind of warning (maybe with a pr_warn (not limited to debug
configs) saying something like "MACsec offload on devices that don't
support md_dst are insecure: they do not provide proper isolation of
traffic"). The comment can stay here.
> if (ether_addr_equal_64bits(hdr->h_dest,
> ndev->dev_addr)) {
> /* exact match, divert skb to this port */
--
Sabrina
