Re: [PATCH] net/macsec copy salt to MACSec ctx for XPN

[Carlos Fernandez]

When macsec offloading is used with XPN, before mdo_add_rxsa
and mdo_add_txsa functions are called, the key salt is not
copied to the macsec context struct.

Fix by copying salt to context struct before calling the
offloading functions.

Fixes: 48ef50fa866a ("macsec: Netlink support of XPN cipher suites")
Signed-off-by: Carlos Fernandez <carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxxx>
---
 drivers/net/macsec.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 832f09ac075e..4f2bd3d722c3 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -1804,6 +1804,14 @@ static int macsec_add_rxsa(struct sk_buff *skb, struct genl_info *info)

        rx_sa->sc = rx_sc;

+       if (secy->xpn) {
+               rx_sa->ssci = nla_get_ssci(tb_sa[MACSEC_SA_ATTR_SSCI]);
+               nla_memcpy(rx_sa->key.salt.bytes, tb_sa[MACSEC_SA_ATTR_SALT],
+                          MACSEC_SALT_LEN);
+       }
+
+       nla_memcpy(rx_sa->key.id, tb_sa[MACSEC_SA_ATTR_KEYID], MACSEC_KEYID_LEN);
+
        /* If h/w offloading is available, propagate to the device */
        if (macsec_is_offloaded(netdev_priv(dev))) {
                const struct macsec_ops *ops;
@@ -1826,13 +1834,6 @@ static int macsec_add_rxsa(struct sk_buff *skb, struct genl_info *info)
                        goto cleanup;
        }

-       if (secy->xpn) {
-               rx_sa->ssci = nla_get_ssci(tb_sa[MACSEC_SA_ATTR_SSCI]);
-               nla_memcpy(rx_sa->key.salt.bytes, tb_sa[MACSEC_SA_ATTR_SALT],
-                          MACSEC_SALT_LEN);
-       }
-
-       nla_memcpy(rx_sa->key.id, tb_sa[MACSEC_SA_ATTR_KEYID], MACSEC_KEYID_LEN);
        rcu_assign_pointer(rx_sc->sa[assoc_num], rx_sa);

        rtnl_unlock();
@@ -2046,6 +2047,14 @@ static int macsec_add_txsa(struct sk_buff *skb, struct genl_info *info)
        if (assoc_num == tx_sc->encoding_sa && tx_sa->active)
                secy->operational = true;

+       if (secy->xpn) {
+               tx_sa->ssci = nla_get_ssci(tb_sa[MACSEC_SA_ATTR_SSCI]);
+               nla_memcpy(tx_sa->key.salt.bytes, tb_sa[MACSEC_SA_ATTR_SALT],
+                          MACSEC_SALT_LEN);
+       }
+
+       nla_memcpy(tx_sa->key.id, tb_sa[MACSEC_SA_ATTR_KEYID], MACSEC_KEYID_LEN);
+
        /* If h/w offloading is available, propagate to the device */
        if (macsec_is_offloaded(netdev_priv(dev))) {
                const struct macsec_ops *ops;
@@ -2068,13 +2077,6 @@ static int macsec_add_txsa(struct sk_buff *skb, struct genl_info *info)
                        goto cleanup;
        }

-       if (secy->xpn) {
-               tx_sa->ssci = nla_get_ssci(tb_sa[MACSEC_SA_ATTR_SSCI]);
-               nla_memcpy(tx_sa->key.salt.bytes, tb_sa[MACSEC_SA_ATTR_SALT],
-                          MACSEC_SALT_LEN);
-       }
-
-       nla_memcpy(tx_sa->key.id, tb_sa[MACSEC_SA_ATTR_KEYID], MACSEC_KEYID_LEN);
        rcu_assign_pointer(tx_sc->sa[assoc_num], tx_sa);

        rtnl_unlock();
--
2.25.1

________________________________________
From: Paolo Abeni <pabeni@xxxxxxxxxx>
Sent: Tuesday, May 3, 2022 1:42 PM
To: Carlos Fernansez
Cc: carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxx; Carlos Fernandez; David S. Miller; Eric Dumazet; Jakub Kicinski; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] net/macsec copy salt to MACSec ctx for XPN

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Hello,

On Mon, 2022-05-02 at 14:18 +0200, Carlos Fernansez wrote:
> From: Carlos Fernandez <carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Salt and KeyId copied to offloading context.
>
> If not, offloaded phys cannot work with XPN
>
> Signed-off-by: Carlos Fernandez <carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxxx>

This looks like a bugfix, could you please provide a relevant 'Fixes'
tag? (in a v2).

Additionally could you please expand the commit message a bit?

Thanks!

Paolo