SAE: 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/ap/ieee802_11.c

@@ -403,7 +403,7 @@ static int check_sae_token(struct hostapd_data *hapd, const u8 *addr,
 		return -1;
 	if (hmac_sha256(hapd->sae_token_key, sizeof(hapd->sae_token_key),
 			addr, ETH_ALEN, mac) < 0 ||
-	    os_memcmp(token, mac, SHA256_MAC_LEN) != 0)
+	    os_memcmp_const(token, mac, SHA256_MAC_LEN) != 0)
 		return -1;
 
 	return 0;

src/common/sae.c

@@ -1051,7 +1051,7 @@ int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
 				   sae->tmp->own_commit_element_ffc,
 				   verifier);
 
-	if (os_memcmp(verifier, data + 2, SHA256_MAC_LEN) != 0) {
+	if (os_memcmp_const(verifier, data + 2, SHA256_MAC_LEN) != 0) {
 		wpa_printf(MSG_DEBUG, "SAE: Confirm mismatch");
 		wpa_hexdump(MSG_DEBUG, "SAE: Received confirm",
 			    data + 2, SHA256_MAC_LEN);