WPS: Remove derivation of management keys

MgmtAuthKey and MgmtEncKey were not used for anything and are unlikely
to ever be used, so better remove the code to reduce binary size.

src/wps/wps_common.c

@@ -129,56 +129,6 @@ int wps_derive_keys(struct wps_data *wps)
 }
 
 
-int wps_derive_mgmt_keys(struct wps_data *wps)
-{
-	u8 nonces[2 * WPS_NONCE_LEN];
-	u8 keys[WPS_MGMTAUTHKEY_LEN + WPS_MGMTENCKEY_LEN];
-	u8 hash[SHA256_MAC_LEN];
-	const u8 *addr[2];
-	size_t len[2];
-	const char *auth_label = "WFA-WLAN-Management-MgmtAuthKey";
-	const char *enc_label = "WFA-WLAN-Management-MgmtEncKey";
-
-	/* MgmtAuthKey || MgmtEncKey =
-	 * kdf(EMSK, N1 || N2 || "WFA-WLAN-Management-Keys", 384) */
-	os_memcpy(nonces, wps->nonce_e, WPS_NONCE_LEN);
-	os_memcpy(nonces + WPS_NONCE_LEN, wps->nonce_r, WPS_NONCE_LEN);
-	wps_kdf(wps->emsk, nonces, sizeof(nonces), "WFA-WLAN-Management-Keys",
-		keys, sizeof(keys));
-	os_memcpy(wps->mgmt_auth_key, keys, WPS_MGMTAUTHKEY_LEN);
-	os_memcpy(wps->mgmt_enc_key, keys + WPS_MGMTAUTHKEY_LEN,
-		  WPS_MGMTENCKEY_LEN);
-
-	addr[0] = nonces;
-	len[0] = sizeof(nonces);
-
-	/* MgmtEncKeyID = first 128 bits of
-	 * SHA-256(N1 || N2 || "WFA-WLAN-Management-MgmtAuthKey") */
-	addr[1] = (const u8 *) auth_label;
-	len[1] = os_strlen(auth_label);
-	sha256_vector(2, addr, len, hash);
-	os_memcpy(wps->mgmt_auth_key_id, hash, WPS_MGMT_KEY_ID_LEN);
-
-	/* MgmtEncKeyID = first 128 bits of
-	 * SHA-256(N1 || N2 || "WFA-WLAN-Management-MgmtEncKey") */
-	addr[1] = (const u8 *) enc_label;
-	len[1] = os_strlen(enc_label);
-	sha256_vector(2, addr, len, hash);
-	os_memcpy(wps->mgmt_enc_key_id, hash, WPS_MGMT_KEY_ID_LEN);
-
-	wpa_hexdump_key(MSG_DEBUG, "WPS: MgmtAuthKey",
-			wps->mgmt_auth_key, WPS_MGMTAUTHKEY_LEN);
-	wpa_hexdump(MSG_DEBUG, "WPS: MgmtAuthKeyID",
-		    wps->mgmt_auth_key_id, WPS_MGMT_KEY_ID_LEN);
-	wpa_hexdump_key(MSG_DEBUG, "WPS: MgmtEncKey",
-			wps->mgmt_enc_key, WPS_MGMTENCKEY_LEN);
-	wpa_hexdump(MSG_DEBUG, "WPS: MgmtEncKeyID",
-		    wps->mgmt_enc_key_id, WPS_MGMT_KEY_ID_LEN);
-
-	return 0;
-}
-
-
 void wps_derive_psk(struct wps_data *wps, const u8 *dev_passwd,
 		    size_t dev_passwd_len)
 {

src/wps/wps_enrollee.c

@@ -555,10 +555,6 @@ static int wps_process_pubkey(struct wps_data *wps, const u8 *pk,
 	if (wps_derive_keys(wps) < 0)
 		return -1;
 
-	if (wps->request_type == WPS_REQ_WLAN_MANAGER_REGISTRAR &&
-	    wps_derive_mgmt_keys(wps) < 0)
-		return -1;
-
 	return 0;
 }
 

src/wps/wps_i.h

@@ -62,10 +62,6 @@ struct wps_data {
 	u8 authkey[WPS_AUTHKEY_LEN];
 	u8 keywrapkey[WPS_KEYWRAPKEY_LEN];
 	u8 emsk[WPS_EMSK_LEN];
-	u8 mgmt_auth_key[WPS_MGMTAUTHKEY_LEN];
-	u8 mgmt_auth_key_id[WPS_MGMT_KEY_ID_LEN];
-	u8 mgmt_enc_key[WPS_MGMTENCKEY_LEN];
-	u8 mgmt_enc_key_id[WPS_MGMT_KEY_ID_LEN];
 
 	struct wpabuf *last_msg;
 
@@ -189,7 +185,6 @@ struct wps_parse_attr {
 void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
 	     const char *label, u8 *res, size_t res_len);
 int wps_derive_keys(struct wps_data *wps);
-int wps_derive_mgmt_keys(struct wps_data *wps);
 void wps_derive_psk(struct wps_data *wps, const u8 *dev_passwd,
 		    size_t dev_passwd_len);
 struct wpabuf * wps_decrypt_encr_settings(struct wps_data *wps, const u8 *encr,