Revert "net: macsec: update SCI upon MAC address change."

This reverts commit ed3cb35c7ab1edb3181aa14dfc9c69aee62c45a6.

Commit ed3cb35c7ab1 states:

    SCI should be updated, because it contains MAC in its first 6
    octets.

That's not entirely correct. The SCI can be based on the MAC address,
but doesn't have to be. We can also use any 64-bit number as the
SCI. When the SCI based on the MAC address, it uses a 16-bit "port
number" provided by userspace, which commit ed3cb35c7ab1 overwrites
with 1.

In addition, changing the SCI after macsec has been setup can just
confuse the receiver. If we configure the RXSC on the peer based on
the original SCI, we should keep the same SCI on TX.

When the macsec device is being managed by a userspace key negotiation
daemon such as wpa_supplicant, commit ed3cb35c7ab1 would also
overwrite the SCI defined by userspace.

Fixes: ed3cb35c7ab1 ("net: macsec: update SCI upon MAC address change.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/9b1a9d28327e7eb54550a92eebda45d25e54dd0d.1660667033.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index ee6087e7b2bfb5db7cd22103285a9a28aa2b8995..c6d271e5687e9e047ee947bbbe10fd9dae29a13e 100644 (file)
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -462,11 +462,6 @@ static struct macsec_eth_header *macsec_ethhdr(struct sk_buff *skb)
        return (struct macsec_eth_header *)skb_mac_header(skb);
 }
 
-static sci_t dev_to_sci(struct net_device *dev, __be16 port)
-{
-       return make_sci(dev->dev_addr, port);
-}
-
 static void __macsec_pn_wrapped(struct macsec_secy *secy,
                                struct macsec_tx_sa *tx_sa)
 {
@@ -3661,7 +3656,6 @@ static int macsec_set_mac_address(struct net_device *dev, void *p)
 
 out:
        eth_hw_addr_set(dev, addr->sa_data);
-       macsec->secy.sci = dev_to_sci(dev, MACSEC_PORT_ES);
 
        /* If h/w offloading is available, propagate to the device */
        if (macsec_is_offloaded(macsec)) {
@@ -4000,6 +3994,11 @@ static bool sci_exists(struct net_device *dev, sci_t sci)
        return false;
 }
 
+static sci_t dev_to_sci(struct net_device *dev, __be16 port)
+{
+       return make_sci(dev->dev_addr, port);
+}
+
 static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len)
 {
        struct macsec_dev *macsec = macsec_priv(dev);