diff mbox series

[net,3/4] macsec: limit replay window size with XPN

Message ID b081da2b1b2600708434ac2379527f42cd81c710.1656519221.git.sd@queasysnail.net (mailing list archive)
State Accepted
Commit b07a0e2044057f201d694ab474f5c42a02b6465b
Delegated to: Netdev Maintainers
Headers show
Series macsec: fix config issues | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4 this patch: 4
netdev/cc_maintainers fail 1 blamed authors not CCed: davem@davemloft.net; 4 maintainers not CCed: davem@davemloft.net edumazet@google.com pabeni@redhat.com kuba@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning WARNING: Block comments use a trailing */ on a separate line
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Sabrina Dubroca July 22, 2022, 9:16 a.m. UTC
IEEE 802.1AEbw-2013 (section 10.7.8) specifies that the maximum value
of the replay window is 2^30-1, to help with recovery of the upper
bits of the PN.

To avoid leaving the existing macsec device in an inconsistent state
if this test fails during changelink, reuse the cleanup mechanism
introduced for HW offload. This wasn't needed until now because
macsec_changelink_common could not fail during changelink, as
modifying the cipher suite was not allowed.

Finally, this must happen after handling IFLA_MACSEC_CIPHER_SUITE so
that secy->xpn is set.

Fixes: 48ef50fa866a ("macsec: Netlink support of XPN cipher suites (IEEE 802.1AEbw)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 drivers/net/macsec.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 634452d3ecc5..b3834e353c22 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -243,6 +243,7 @@  static struct macsec_cb *macsec_skb_cb(struct sk_buff *skb)
 #define DEFAULT_SEND_SCI true
 #define DEFAULT_ENCRYPT false
 #define DEFAULT_ENCODING_SA 0
+#define MACSEC_XPN_MAX_REPLAY_WINDOW (((1 << 30) - 1))
 
 static bool send_sci(const struct macsec_secy *secy)
 {
@@ -3746,9 +3747,6 @@  static int macsec_changelink_common(struct net_device *dev,
 		secy->operational = tx_sa && tx_sa->active;
 	}
 
-	if (data[IFLA_MACSEC_WINDOW])
-		secy->replay_window = nla_get_u32(data[IFLA_MACSEC_WINDOW]);
-
 	if (data[IFLA_MACSEC_ENCRYPT])
 		tx_sc->encrypt = !!nla_get_u8(data[IFLA_MACSEC_ENCRYPT]);
 
@@ -3794,6 +3792,16 @@  static int macsec_changelink_common(struct net_device *dev,
 		}
 	}
 
+	if (data[IFLA_MACSEC_WINDOW]) {
+		secy->replay_window = nla_get_u32(data[IFLA_MACSEC_WINDOW]);
+
+		/* IEEE 802.1AEbw-2013 10.7.8 - maximum replay window
+		 * for XPN cipher suites */
+		if (secy->xpn &&
+		    secy->replay_window > MACSEC_XPN_MAX_REPLAY_WINDOW)
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -3823,7 +3831,7 @@  static int macsec_changelink(struct net_device *dev, struct nlattr *tb[],
 
 	ret = macsec_changelink_common(dev, data);
 	if (ret)
-		return ret;
+		goto cleanup;
 
 	/* If h/w offloading is available, propagate to the device */
 	if (macsec_is_offloaded(macsec)) {