wpa_supplicant: Add macsec_integ_only setting for MKA

So that the user can turn encryption on (MACsec provides
confidentiality+integrity) or off (MACsec provides integrity only). This
commit adds the configuration parameter while the actual behavior change
to disable encryption in the driver is handled in the following commit.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>

src/common/ieee802_1x_defs.h

@@ -25,6 +25,12 @@ enum macsec_policy {
 	 * Disabled MACsec - do not secure sessions.
 	 */
 	DO_NOT_SECURE,
+
+	/**
+	 * Should secure sessions, and try to use encryption.
+	 * Like @SHOULD_SECURE, this follows the key server's decision.
+	 */
+	SHOULD_ENCRYPT,
 };
 
 

src/pae/ieee802_1x_kay.c

@@ -3129,6 +3129,7 @@ ieee802_1x_kay_init(struct ieee802_1x_kay_ctx *ctx, enum macsec_policy policy,
 	} else {
 		kay->macsec_desired = TRUE;
 		kay->macsec_protect = TRUE;
+		kay->macsec_encrypt = policy == SHOULD_ENCRYPT;
 		kay->macsec_validate = Strict;
 		kay->macsec_replay_protect = FALSE;
 		kay->macsec_replay_window = 0;

src/pae/ieee802_1x_kay.h

@@ -181,6 +181,7 @@ struct ieee802_1x_kay {
 	enum macsec_cap macsec_capable;
 	Boolean macsec_desired;
 	Boolean macsec_protect;
+	Boolean macsec_encrypt;
 	Boolean macsec_replay_protect;
 	u32 macsec_replay_window;
 	enum validate_frames macsec_validate;

wpa_supplicant/config.c

@@ -2125,6 +2125,7 @@ static const struct parse_data ssid_fields[] = {
 	{ INT(beacon_int) },
 #ifdef CONFIG_MACSEC
 	{ INT_RANGE(macsec_policy, 0, 1) },
+	{ INT_RANGE(macsec_integ_only, 0, 1) },
 	{ FUNC_KEY(mka_cak) },
 	{ FUNC_KEY(mka_ckn) },
 #endif /* CONFIG_MACSEC */

wpa_supplicant/config_file.c

@@ -808,6 +808,7 @@ static void wpa_config_write_network(FILE *f, struct wpa_ssid *ssid)
 	INT(macsec_policy);
 	write_mka_cak(f, ssid);
 	write_mka_ckn(f, ssid);
+	INT(macsec_integ_only);
 #endif /* CONFIG_MACSEC */
 #ifdef CONFIG_HS20
 	INT(update_identifier);

wpa_supplicant/config_ssid.h

@@ -729,6 +729,18 @@ struct wpa_ssid {
 	 */
 	int macsec_policy;
 
+	/**
+	 * macsec_integ_only - Determines how MACsec are transmitted
+	 *
+	 * This setting applies only when MACsec is in use, i.e.,
+	 *  - macsec_policy is enabled
+	 *  - the key server has decided to enable MACsec
+	 *
+	 * 0: Encrypt traffic (default)
+	 * 1: Integrity only
+	 */
+	int macsec_integ_only;
+
 	/**
 	 * mka_ckn - MKA pre-shared CKN
 	 */

wpa_supplicant/wpa_cli.c

@@ -1390,6 +1390,7 @@ static const char *network_fields[] = {
 	"ap_max_inactivity", "dtim_period", "beacon_int",
 #ifdef CONFIG_MACSEC
 	"macsec_policy",
+	"macsec_integ_only",
 #endif /* CONFIG_MACSEC */
 #ifdef CONFIG_HS20
 	"update_identifier",

wpa_supplicant/wpa_supplicant.conf

@@ -892,6 +892,13 @@ fast_reauth=1
 # 1: MACsec enabled - Should secure, accept key server's advice to
 #    determine whether to use a secure session or not.
 #
+# macsec_integ_only: IEEE 802.1X/MACsec transmit mode
+# This setting applies only when MACsec is in use, i.e.,
+#  - macsec_policy is enabled
+#  - the key server has decided to enable MACsec
+# 0: Encrypt traffic (default)
+# 1: Integrity only
+#
 # mka_cak and mka_ckn: IEEE 802.1X/MACsec pre-shared authentication mode
 # This allows to configure MACsec with a pre-shared key using a (CAK,CKN) pair.
 # In this mode, instances of wpa_supplicant can act as peers, one of

wpa_supplicant/wpas_kay.c

@@ -187,7 +187,14 @@ int ieee802_1x_alloc_kay_sm(struct wpa_supplicant *wpa_s, struct wpa_ssid *ssid)
 	if (!ssid || ssid->macsec_policy == 0)
 		return 0;
 
-	policy = ssid->macsec_policy == 1 ? SHOULD_SECURE : DO_NOT_SECURE;
+	if (ssid->macsec_policy == 1) {
+		if (ssid->macsec_integ_only == 1)
+			policy = SHOULD_SECURE;
+		else
+			policy = SHOULD_ENCRYPT;
+	} else {
+		policy = DO_NOT_SECURE;
+	}
 
 	kay_ctx = os_zalloc(sizeof(*kay_ctx));
 	if (!kay_ctx)