Check hmac_md5() result in radius_msg_verify_msg_auth()

This gets rid of a valgrind warning on uninitialized memory read in the
hostapd_oom_wpa2_eap_connect test case where memcmp is used after failed
hmac_md5() call.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/radius/radius.c

@@ -818,8 +818,9 @@ int radius_msg_verify_msg_auth(struct radius_msg *msg, const u8 *secret,
 		os_memcpy(msg->hdr->authenticator, req_auth,
 			  sizeof(msg->hdr->authenticator));
 	}
-	hmac_md5(secret, secret_len, wpabuf_head(msg->buf),
-		 wpabuf_len(msg->buf), auth);
+	if (hmac_md5(secret, secret_len, wpabuf_head(msg->buf),
+		     wpabuf_len(msg->buf), auth) < 0)
+		return 1;
 	os_memcpy(attr + 1, orig, MD5_MAC_LEN);
 	if (req_auth) {
 		os_memcpy(msg->hdr->authenticator, orig_authenticator,