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Message-ID: <20240419011740.333714-3-rrameshbabu@nvidia.com>
Date: Thu, 18 Apr 2024 18:17:16 -0700
From: Rahul Rameshbabu <rrameshbabu@...dia.com>
To: netdev@...r.kernel.org,
stable@...r.kernel.org
Cc: Jakub Kicinski <kuba@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
"David S. Miller" <davem@...emloft.net>,
Paolo Abeni <pabeni@...hat.com>,
Gal Pressman <gal@...dia.com>,
Tariq Toukan <tariqt@...dia.com>,
Sabrina Dubroca <sd@...asysnail.net>,
Yossi Kuperman <yossiku@...dia.com>,
Benjamin Poirier <bpoirier@...dia.com>,
Cosmin Ratiu <cratiu@...dia.com>,
Rahul Rameshbabu <rrameshbabu@...dia.com>
Subject: [PATCH net-next 2/3] macsec: Detect if Rx skb is macsec-related for offloading devices that update md_dst
Can now correctly identify where the packets should be delivered by using
md_dst or its absence on devices that provide it.
This detection is not possible without device drivers that update md_dst. A
fallback pattern should be used for supporting such device drivers. This
fallback mode causes multicast messages to be cloned to both the non-macsec
and macsec ports, independent of whether the multicast message received was
encrypted over MACsec or not. Other non-macsec traffic may also fail to be
handled correctly for devices in promiscuous mode.
Link: https://lore.kernel.org/netdev/ZULRxX9eIbFiVi7v@hog/
Cc: Sabrina Dubroca <sd@...asysnail.net>
Cc: stable@...r.kernel.org
Signed-off-by: Rahul Rameshbabu <rrameshbabu@...dia.com>
Reviewed-by: Benjamin Poirier <bpoirier@...dia.com>
Reviewed-by: Cosmin Ratiu <cratiu@...dia.com>
---
drivers/net/macsec.c | 57 +++++++++++++++++++++++++++++++++++++-------
1 file changed, 48 insertions(+), 9 deletions(-)
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)
+
+{
+ 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;
+ 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 (ether_addr_equal_64bits(hdr->h_dest,
ndev->dev_addr)) {
/* exact match, divert skb to this port */
@@ -1036,14 +1078,11 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
break;
nskb->dev = ndev;
- if (ether_addr_equal_64bits(hdr->h_dest,
- ndev->broadcast))
- nskb->pkt_type = PACKET_BROADCAST;
- else
- nskb->pkt_type = PACKET_MULTICAST;
+ nskb->pkt_type = macsec_offload_pkt_type(
+ hdr->h_dest, ndev->broadcast);
__netif_rx(nskb);
- } else if (rx_sc || ndev->flags & IFF_PROMISC) {
+ } else if (ndev->flags & IFF_PROMISC) {
skb->dev = ndev;
skb->pkt_type = PACKET_HOST;
ret = RX_HANDLER_ANOTHER;
--
2.42.0
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