EAP-SIM/AKA: Use os_memcmp_const() for hash/password comparisons

This makes the implementation less likely to provide useful timing
information to potential attackers from comparisons of information
received from a remote device and private material known only by the
authorized devices.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/eap_common/eap_sim_common.c

@@ -198,7 +198,7 @@ int eap_sim_verify_mac(const u8 *k_aut, const struct wpabuf *req,
 		    hmac, EAP_SIM_MAC_LEN);
 	os_free(tmp);
 
-	return (os_memcmp(hmac, mac, EAP_SIM_MAC_LEN) == 0) ? 0 : 1;
+	return (os_memcmp_const(hmac, mac, EAP_SIM_MAC_LEN) == 0) ? 0 : 1;
 }
 
 
@@ -393,7 +393,7 @@ int eap_sim_verify_mac_sha256(const u8 *k_aut, const struct wpabuf *req,
 		    hmac, EAP_SIM_MAC_LEN);
 	os_free(tmp);
 
-	return (os_memcmp(hmac, mac, EAP_SIM_MAC_LEN) == 0) ? 0 : 1;
+	return (os_memcmp_const(hmac, mac, EAP_SIM_MAC_LEN) == 0) ? 0 : 1;
 }
 
 

src/eap_peer/eap_aka.c

@@ -294,7 +294,7 @@ static int eap_aka_umts_auth(struct eap_sm *sm, struct eap_aka_data *data)
 	{
 		u8 autn[EAP_AKA_AUTN_LEN];
 		os_memset(autn, '1', EAP_AKA_AUTN_LEN);
-		if (os_memcmp(autn, data->autn, EAP_AKA_AUTN_LEN) != 0) {
+		if (os_memcmp_const(autn, data->autn, EAP_AKA_AUTN_LEN) != 0) {
 			wpa_printf(MSG_WARNING, "EAP-AKA: AUTN did not match "
 				   "with expected value");
 			return -1;
@@ -509,7 +509,7 @@ static int eap_aka_verify_checkcode(struct eap_aka_data *data,
 #endif /* EAP_AKA_PRIME */
 		sha1_vector(1, &addr, &len, hash);
 
-	if (os_memcmp(hash, checkcode, hash_len) != 0) {
+	if (os_memcmp_const(hash, checkcode, hash_len) != 0) {
 		wpa_printf(MSG_DEBUG, "EAP-AKA: Mismatch in AT_CHECKCODE");
 		return -1;
 	}

src/eap_server/eap_server_aka.c

@@ -336,7 +336,7 @@ static int eap_aka_verify_checkcode(struct eap_aka_data *data,
 	else
 		sha1_vector(1, &addr, &len, hash);
 
-	if (os_memcmp(hash, checkcode, hash_len) != 0) {
+	if (os_memcmp_const(hash, checkcode, hash_len) != 0) {
 		wpa_printf(MSG_DEBUG, "EAP-AKA: Mismatch in AT_CHECKCODE");
 		return -1;
 	}
@@ -963,7 +963,7 @@ static void eap_aka_process_challenge(struct eap_sm *sm,
 	 */
 	if (attr->res == NULL || attr->res_len < data->res_len ||
 	    attr->res_len_bits != data->res_len * 8 ||
-	    os_memcmp(attr->res, data->res, data->res_len) != 0) {
+	    os_memcmp_const(attr->res, data->res, data->res_len) != 0) {
 		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message did not "
 			   "include valid AT_RES (attr len=%lu, res len=%lu "
 			   "bits, expected %lu bits)",