- unsigned int servname_type;
- PACKET sni, hostname;
-
- /*-
- * The servername extension is treated as follows:
- *
- * - Only the hostname type is supported with a maximum length of 255.
- * - The servername is rejected if too long or if it contains zeros,
- * in which case an fatal alert is generated.
- * - The servername field is maintained together with the session cache.
- * - When a session is resumed, the servername call back invoked in order
- * to allow the application to position itself to the right context.
- * - The servername is acknowledged if it is new for a session or when
- * it is identical to a previously used for the same session.
- * Applications can control the behaviour. They can at any time
- * set a 'desirable' servername for a new SSL object. This can be the
- * case for example with HTTPS when a Host: header field is received and
- * a renegotiation is requested. In this case, a possible servername
- * presented in the new client hello is only acknowledged if it matches
- * the value of the Host: field.
- * - Applications must use SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
- * if they provide for changing an explicit servername context for the
- * session, i.e. when the session has been established with a servername
- * extension.
- * - On session reconnect, the servername extension may be absent.
- *
- */
- if (!PACKET_as_length_prefixed_2(pkt, &sni)
- /* ServerNameList must be at least 1 byte long. */
- || PACKET_remaining(&sni) == 0) {
- *al = SSL_AD_DECODE_ERROR;
- return 0;
- }
-
- /*
- * Although the server_name extension was intended to be
- * extensible to new name types, RFC 4366 defined the
- * syntax inextensibility and OpenSSL 1.0.x parses it as
- * such.
- * RFC 6066 corrected the mistake but adding new name types
- * is nevertheless no longer feasible, so act as if no other
- * SNI types can exist, to simplify parsing.
- *
- * Also note that the RFC permits only one SNI value per type,
- * i.e., we can only have a single hostname.
- */
- if (!PACKET_get_1(&sni, &servname_type)
- || servname_type != TLSEXT_NAMETYPE_host_name
- || !PACKET_as_length_prefixed_2(&sni, &hostname)) {
- *al = SSL_AD_DECODE_ERROR;
- return 0;
- }
-
- if (!s->hit) {
- if (PACKET_remaining(&hostname) > TLSEXT_MAXLEN_host_name) {
- *al = TLS1_AD_UNRECOGNIZED_NAME;
- return 0;
- }
-
- if (PACKET_contains_zero_byte(&hostname)) {
- *al = TLS1_AD_UNRECOGNIZED_NAME;
- return 0;
- }
-
- if (!PACKET_strndup(&hostname, &s->session->tlsext_hostname)) {
- *al = TLS1_AD_INTERNAL_ERROR;
- return 0;
- }
-
- s->servername_done = 1;
- } else {
- /*
- * TODO(openssl-team): if the SNI doesn't match, we MUST
- * fall back to a full handshake.
- */
- s->servername_done = s->session->tlsext_hostname
- && PACKET_equal(&hostname, s->session->tlsext_hostname,
- strlen(s->session->tlsext_hostname));
- }
projects / openssl.git / blobdiff