EAP-GPSK: Check HMAC-SHA256 result in GKDF and MIC

hmac_sha256() and hmac_sha256_vector() return a result code now, so use
that return value to terminate HMAC-SHA256-based GKDF/MIC similarly to
what was already done with the CMAC-based GKDF/MIC.

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

src/eap_common/eap_gpsk_common.c

@@ -92,7 +92,8 @@ static int eap_gpsk_gkdf_sha256(const u8 *psk /* Y */,
 	n = (len + hashlen - 1) / hashlen;
 	for (i = 1; i <= n; i++) {
 		WPA_PUT_BE16(ibuf, i);
-		hmac_sha256_vector(psk, 32, 2, addr, vlen, hash);
+		if (hmac_sha256_vector(psk, 32, 2, addr, vlen, hash))
+			return -1;
 		clen = left > hashlen ? hashlen : left;
 		os_memcpy(opos, hash, clen);
 		opos += clen;
@@ -534,8 +535,7 @@ int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
 		break;
 #ifdef EAP_GPSK_SHA256
 	case EAP_GPSK_CIPHER_SHA256:
-		hmac_sha256(sk, sk_len, data, len, mic);
-		ret = 0;
+		ret = hmac_sha256(sk, sk_len, data, len, mic);
 		break;
 #endif /* EAP_GPSK_SHA256 */
 	default:
@@ -545,5 +545,8 @@ int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
 		break;
 	}
 
+	if (ret)
+		wpa_printf(MSG_DEBUG, "EAP-GPSK: Could not compute MIC");
+
 	return ret;
 }