EAP-PEAP: 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_peer/eap_peap.c

@@ -423,7 +423,7 @@ static int eap_tlv_validate_cryptobinding(struct eap_sm *sm,
 		    buf, sizeof(buf));
 	hmac_sha1(data->cmk, 20, buf, sizeof(buf), mac);
 
-	if (os_memcmp(mac, pos, SHA1_MAC_LEN) != 0) {
+	if (os_memcmp_const(mac, pos, SHA1_MAC_LEN) != 0) {
 		wpa_printf(MSG_DEBUG, "EAP-PEAP: Invalid Compound_MAC in "
 			   "cryptobinding TLV");
 		wpa_hexdump(MSG_DEBUG, "EAP-PEAP: Received MAC",

src/eap_server/eap_server_peap.c

@@ -593,7 +593,7 @@ static int eap_tlv_validate_cryptobinding(struct eap_sm *sm,
 	buf[60] = EAP_TYPE_PEAP;
 	hmac_sha1(data->cmk, 20, buf, sizeof(buf), mac);
 
-	if (os_memcmp(mac, pos, SHA1_MAC_LEN) != 0) {
+	if (os_memcmp_const(mac, pos, SHA1_MAC_LEN) != 0) {
 		wpa_printf(MSG_DEBUG, "EAP-PEAP: Invalid Compound_MAC in "
 			   "cryptobinding TLV");
 		wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: CMK", data->cmk, 20);