Add submodule dependency filesHEADmaster

Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec

1 files changed, 1974 insertions, 0 deletions

diff --git a/roms/edk2/CryptoPkg/Library/OpensslLib/openssl/ssl/statem/extensions_srvr.c b/roms/edk2/CryptoPkg/Library/OpensslLib/openssl/ssl/statem/extensions_srvr.c
new file mode 100644
index 000000000..3b07c6b94
--- /dev/null
+++ b/roms/edk2/CryptoPkg/Library/OpensslLib/openssl/ssl/statem/extensions_srvr.c
@@ -0,0 +1,1974 @@
+/*
+ * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/ocsp.h>
+#include "../ssl_local.h"
+#include "statem_local.h"
+#include "internal/cryptlib.h"
+
+#define COOKIE_STATE_FORMAT_VERSION     0
+
+/*
+ * 2 bytes for packet length, 2 bytes for format version, 2 bytes for
+ * protocol version, 2 bytes for group id, 2 bytes for cipher id, 1 byte for
+ * key_share present flag, 4 bytes for timestamp, 2 bytes for the hashlen,
+ * EVP_MAX_MD_SIZE for transcript hash, 1 byte for app cookie length, app cookie
+ * length bytes, SHA256_DIGEST_LENGTH bytes for the HMAC of the whole thing.
+ */
+#define MAX_COOKIE_SIZE (2 + 2 + 2 + 2 + 2 + 1 + 4 + 2 + EVP_MAX_MD_SIZE + 1 \
+                         + SSL_COOKIE_LENGTH + SHA256_DIGEST_LENGTH)
+
+/*
+ * Message header + 2 bytes for protocol version + number of random bytes +
+ * + 1 byte for legacy session id length + number of bytes in legacy session id
+ * + 2 bytes for ciphersuite + 1 byte for legacy compression
+ * + 2 bytes for extension block length + 6 bytes for key_share extension
+ * + 4 bytes for cookie extension header + the number of bytes in the cookie
+ */
+#define MAX_HRR_SIZE    (SSL3_HM_HEADER_LENGTH + 2 + SSL3_RANDOM_SIZE + 1 \
+                         + SSL_MAX_SSL_SESSION_ID_LENGTH + 2 + 1 + 2 + 6 + 4 \
+                         + MAX_COOKIE_SIZE)
+
+/*
+ * Parse the client's renegotiation binding and abort if it's not right
+ */
+int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
+                               X509 *x, size_t chainidx)
+{
+    unsigned int ilen;
+    const unsigned char *data;
+
+    /* Parse the length byte */
+    if (!PACKET_get_1(pkt, &ilen)
+        || !PACKET_get_bytes(pkt, &data, ilen)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
+                 SSL_R_RENEGOTIATION_ENCODING_ERR);
+        return 0;
+    }
+
+    /* Check that the extension matches */
+    if (ilen != s->s3->previous_client_finished_len) {
+        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
+                 SSL_R_RENEGOTIATION_MISMATCH);
+        return 0;
+    }
+
+    if (memcmp(data, s->s3->previous_client_finished,
+               s->s3->previous_client_finished_len)) {
+        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
+                 SSL_R_RENEGOTIATION_MISMATCH);
+        return 0;
+    }
+
+    s->s3->send_connection_binding = 1;
+
+    return 1;
+}
+
+/*-
+ * 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.
+ */
+int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, unsigned int context,
+                               X509 *x, size_t chainidx)
+{
+    unsigned int servname_type;
+    PACKET sni, hostname;
+
+    if (!PACKET_as_length_prefixed_2(pkt, &sni)
+        /* ServerNameList must be at least 1 byte long. */
+        || PACKET_remaining(&sni) == 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    /*
+     * Although the intent was for server_name to be extensible, RFC 4366
+     * was not clear about it; and so OpenSSL among other implementations,
+     * always and only allows a 'host_name' name types.
+     * 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)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    /*
+     * In TLSv1.2 and below the SNI is associated with the session. In TLSv1.3
+     * we always use the SNI value from the handshake.
+     */
+    if (!s->hit || SSL_IS_TLS13(s)) {
+        if (PACKET_remaining(&hostname) > TLSEXT_MAXLEN_host_name) {
+            SSLfatal(s, SSL_AD_UNRECOGNIZED_NAME,
+                     SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
+                     SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+        if (PACKET_contains_zero_byte(&hostname)) {
+            SSLfatal(s, SSL_AD_UNRECOGNIZED_NAME,
+                     SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
+                     SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+        /*
+         * Store the requested SNI in the SSL as temporary storage.
+         * If we accept it, it will get stored in the SSL_SESSION as well.
+         */
+        OPENSSL_free(s->ext.hostname);
+        s->ext.hostname = NULL;
+        if (!PACKET_strndup(&hostname, &s->ext.hostname)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_SERVER_NAME,
+                     ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+
+        s->servername_done = 1;
+    } else {
+        /*
+         * In TLSv1.2 and below we should check if the SNI is consistent between
+         * the initial handshake and the resumption. In TLSv1.3 SNI is not
+         * associated with the session.
+         */
+        /*
+         * TODO(openssl-team): if the SNI doesn't match, we MUST
+         * fall back to a full handshake.
+         */
+        s->servername_done = (s->session->ext.hostname != NULL)
+            && PACKET_equal(&hostname, s->session->ext.hostname,
+                            strlen(s->session->ext.hostname));
+    }
+
+    return 1;
+}
+
+int tls_parse_ctos_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    unsigned int value;
+
+    if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    /* Received |value| should be a valid max-fragment-length code. */
+    if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                 SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
+                 SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
+        return 0;
+    }
+
+    /*
+     * RFC 6066:  The negotiated length applies for the duration of the session
+     * including session resumptions.
+     * We should receive the same code as in resumed session !
+     */
+    if (s->hit && s->session->ext.max_fragment_len_mode != value) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                 SSL_F_TLS_PARSE_CTOS_MAXFRAGMENTLEN,
+                 SSL_R_SSL3_EXT_INVALID_MAX_FRAGMENT_LENGTH);
+        return 0;
+    }
+
+    /*
+     * Store it in session, so it'll become binding for us
+     * and we'll include it in a next Server Hello.
+     */
+    s->session->ext.max_fragment_len_mode = value;
+    return 1;
+}
+
+#ifndef OPENSSL_NO_SRP
+int tls_parse_ctos_srp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                       size_t chainidx)
+{
+    PACKET srp_I;
+
+    if (!PACKET_as_length_prefixed_1(pkt, &srp_I)
+            || PACKET_contains_zero_byte(&srp_I)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SRP,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    /*
+     * TODO(openssl-team): currently, we re-authenticate the user
+     * upon resumption. Instead, we MUST ignore the login.
+     */
+    if (!PACKET_strndup(&srp_I, &s->srp_ctx.login)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_SRP,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    return 1;
+}
+#endif
+
+#ifndef OPENSSL_NO_EC
+int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
+                                 X509 *x, size_t chainidx)
+{
+    PACKET ec_point_format_list;
+
+    if (!PACKET_as_length_prefixed_1(pkt, &ec_point_format_list)
+        || PACKET_remaining(&ec_point_format_list) == 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_EC_PT_FORMATS,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (!s->hit) {
+        if (!PACKET_memdup(&ec_point_format_list,
+                           &s->ext.peer_ecpointformats,
+                           &s->ext.peer_ecpointformats_len)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+    }
+
+    return 1;
+}
+#endif                          /* OPENSSL_NO_EC */
+
+int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    if (s->ext.session_ticket_cb &&
+            !s->ext.session_ticket_cb(s, PACKET_data(pkt),
+                                  PACKET_remaining(pkt),
+                                  s->ext.session_ticket_cb_arg)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    return 1;
+}
+
+int tls_parse_ctos_sig_algs_cert(SSL *s, PACKET *pkt, unsigned int context,
+                                 X509 *x, size_t chainidx)
+{
+    PACKET supported_sig_algs;
+
+    if (!PACKET_as_length_prefixed_2(pkt, &supported_sig_algs)
+            || PACKET_remaining(&supported_sig_algs) == 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SIG_ALGS_CERT, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (!s->hit && !tls1_save_sigalgs(s, &supported_sig_algs, 1)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SIG_ALGS_CERT, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    return 1;
+}
+
+int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                            size_t chainidx)
+{
+    PACKET supported_sig_algs;
+
+    if (!PACKET_as_length_prefixed_2(pkt, &supported_sig_algs)
+            || PACKET_remaining(&supported_sig_algs) == 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SIG_ALGS, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (!s->hit && !tls1_save_sigalgs(s, &supported_sig_algs, 0)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SIG_ALGS, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    return 1;
+}
+
+#ifndef OPENSSL_NO_OCSP
+int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    PACKET responder_id_list, exts;
+
+    /* We ignore this in a resumption handshake */
+    if (s->hit)
+        return 1;
+
+    /* Not defined if we get one of these in a client Certificate */
+    if (x != NULL)
+        return 1;
+
+    if (!PACKET_get_1(pkt, (unsigned int *)&s->ext.status_type)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
+        /*
+         * We don't know what to do with any other type so ignore it.
+         */
+        s->ext.status_type = TLSEXT_STATUSTYPE_nothing;
+        return 1;
+    }
+
+    if (!PACKET_get_length_prefixed_2 (pkt, &responder_id_list)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    /*
+     * We remove any OCSP_RESPIDs from a previous handshake
+     * to prevent unbounded memory growth - CVE-2016-6304
+     */
+    sk_OCSP_RESPID_pop_free(s->ext.ocsp.ids, OCSP_RESPID_free);
+    if (PACKET_remaining(&responder_id_list) > 0) {
+        s->ext.ocsp.ids = sk_OCSP_RESPID_new_null();
+        if (s->ext.ocsp.ids == NULL) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, ERR_R_MALLOC_FAILURE);
+            return 0;
+        }
+    } else {
+        s->ext.ocsp.ids = NULL;
+    }
+
+    while (PACKET_remaining(&responder_id_list) > 0) {
+        OCSP_RESPID *id;
+        PACKET responder_id;
+        const unsigned char *id_data;
+
+        if (!PACKET_get_length_prefixed_2(&responder_id_list, &responder_id)
+                || PACKET_remaining(&responder_id) == 0) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+        id_data = PACKET_data(&responder_id);
+        /* TODO(size_t): Convert d2i_* to size_t */
+        id = d2i_OCSP_RESPID(NULL, &id_data,
+                             (int)PACKET_remaining(&responder_id));
+        if (id == NULL) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+        if (id_data != PACKET_end(&responder_id)) {
+            OCSP_RESPID_free(id);
+            SSLfatal(s, SSL_AD_DECODE_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+
+            return 0;
+        }
+
+        if (!sk_OCSP_RESPID_push(s->ext.ocsp.ids, id)) {
+            OCSP_RESPID_free(id);
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
+
+            return 0;
+        }
+    }
+
+    /* Read in request_extensions */
+    if (!PACKET_as_length_prefixed_2(pkt, &exts)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (PACKET_remaining(&exts) > 0) {
+        const unsigned char *ext_data = PACKET_data(&exts);
+
+        sk_X509_EXTENSION_pop_free(s->ext.ocsp.exts,
+                                   X509_EXTENSION_free);
+        s->ext.ocsp.exts =
+            d2i_X509_EXTENSIONS(NULL, &ext_data, (int)PACKET_remaining(&exts));
+        if (s->ext.ocsp.exts == NULL || ext_data != PACKET_end(&exts)) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_STATUS_REQUEST, SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+    }
+
+    return 1;
+}
+#endif
+
+#ifndef OPENSSL_NO_NEXTPROTONEG
+int tls_parse_ctos_npn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                       size_t chainidx)
+{
+    /*
+     * We shouldn't accept this extension on a
+     * renegotiation.
+     */
+    if (SSL_IS_FIRST_HANDSHAKE(s))
+        s->s3->npn_seen = 1;
+
+    return 1;
+}
+#endif
+
+/*
+ * Save the ALPN extension in a ClientHello.|pkt| holds the contents of the ALPN
+ * extension, not including type and length. Returns: 1 on success, 0 on error.
+ */
+int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                        size_t chainidx)
+{
+    PACKET protocol_list, save_protocol_list, protocol;
+
+    if (!SSL_IS_FIRST_HANDSHAKE(s))
+        return 1;
+
+    if (!PACKET_as_length_prefixed_2(pkt, &protocol_list)
+        || PACKET_remaining(&protocol_list) < 2) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    save_protocol_list = protocol_list;
+    do {
+        /* Protocol names can't be empty. */
+        if (!PACKET_get_length_prefixed_1(&protocol_list, &protocol)
+                || PACKET_remaining(&protocol) == 0) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
+                     SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+    } while (PACKET_remaining(&protocol_list) != 0);
+
+    OPENSSL_free(s->s3->alpn_proposed);
+    s->s3->alpn_proposed = NULL;
+    s->s3->alpn_proposed_len = 0;
+    if (!PACKET_memdup(&save_protocol_list,
+                       &s->s3->alpn_proposed, &s->s3->alpn_proposed_len)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_ALPN,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    return 1;
+}
+
+#ifndef OPENSSL_NO_SRTP
+int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                            size_t chainidx)
+{
+    STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
+    unsigned int ct, mki_len, id;
+    int i, srtp_pref;
+    PACKET subpkt;
+
+    /* Ignore this if we have no SRTP profiles */
+    if (SSL_get_srtp_profiles(s) == NULL)
+        return 1;
+
+    /* Pull off the length of the cipher suite list  and check it is even */
+    if (!PACKET_get_net_2(pkt, &ct) || (ct & 1) != 0
+            || !PACKET_get_sub_packet(pkt, &subpkt, ct)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
+               SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+        return 0;
+    }
+
+    srvr = SSL_get_srtp_profiles(s);
+    s->srtp_profile = NULL;
+    /* Search all profiles for a match initially */
+    srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr);
+
+    while (PACKET_remaining(&subpkt)) {
+        if (!PACKET_get_net_2(&subpkt, &id)) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
+                     SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+            return 0;
+        }
+
+        /*
+         * Only look for match in profiles of higher preference than
+         * current match.
+         * If no profiles have been have been configured then this
+         * does nothing.
+         */
+        for (i = 0; i < srtp_pref; i++) {
+            SRTP_PROTECTION_PROFILE *sprof =
+                sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
+
+            if (sprof->id == id) {
+                s->srtp_profile = sprof;
+                srtp_pref = i;
+                break;
+            }
+        }
+    }
+
+    /* Now extract the MKI value as a sanity check, but discard it for now */
+    if (!PACKET_get_1(pkt, &mki_len)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
+                 SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+        return 0;
+    }
+
+    if (!PACKET_forward(pkt, mki_len)
+        || PACKET_remaining(pkt)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_USE_SRTP,
+                 SSL_R_BAD_SRTP_MKI_VALUE);
+        return 0;
+    }
+
+    return 1;
+}
+#endif
+
+int tls_parse_ctos_etm(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                       size_t chainidx)
+{
+    if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC))
+        s->ext.use_etm = 1;
+
+    return 1;
+}
+
+/*
+ * Process a psk_kex_modes extension received in the ClientHello. |pkt| contains
+ * the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
+ */
+int tls_parse_ctos_psk_kex_modes(SSL *s, PACKET *pkt, unsigned int context,
+                                 X509 *x, size_t chainidx)
+{
+#ifndef OPENSSL_NO_TLS1_3
+    PACKET psk_kex_modes;
+    unsigned int mode;
+
+    if (!PACKET_as_length_prefixed_1(pkt, &psk_kex_modes)
+            || PACKET_remaining(&psk_kex_modes) == 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK_KEX_MODES,
+                 SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    while (PACKET_get_1(&psk_kex_modes, &mode)) {
+        if (mode == TLSEXT_KEX_MODE_KE_DHE)
+            s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE_DHE;
+        else if (mode == TLSEXT_KEX_MODE_KE
+                && (s->options & SSL_OP_ALLOW_NO_DHE_KEX) != 0)
+            s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
+    }
+#endif
+
+    return 1;
+}
+
+/*
+ * Process a key_share extension received in the ClientHello. |pkt| contains
+ * the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
+ */
+int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                             size_t chainidx)
+{
+#ifndef OPENSSL_NO_TLS1_3
+    unsigned int group_id;
+    PACKET key_share_list, encoded_pt;
+    const uint16_t *clntgroups, *srvrgroups;
+    size_t clnt_num_groups, srvr_num_groups;
+    int found = 0;
+
+    if (s->hit && (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE) == 0)
+        return 1;
+
+    /* Sanity check */
+    if (s->s3->peer_tmp != NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    if (!PACKET_as_length_prefixed_2(pkt, &key_share_list)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+
+    /* Get our list of supported groups */
+    tls1_get_supported_groups(s, &srvrgroups, &srvr_num_groups);
+    /* Get the clients list of supported groups. */
+    tls1_get_peer_groups(s, &clntgroups, &clnt_num_groups);
+    if (clnt_num_groups == 0) {
+        /*
+         * This can only happen if the supported_groups extension was not sent,
+         * because we verify that the length is non-zero when we process that
+         * extension.
+         */
+        SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                 SSL_R_MISSING_SUPPORTED_GROUPS_EXTENSION);
+        return 0;
+    }
+
+    if (s->s3->group_id != 0 && PACKET_remaining(&key_share_list) == 0) {
+        /*
+         * If we set a group_id already, then we must have sent an HRR
+         * requesting a new key_share. If we haven't got one then that is an
+         * error
+         */
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                 SSL_R_BAD_KEY_SHARE);
+        return 0;
+    }
+
+    while (PACKET_remaining(&key_share_list) > 0) {
+        if (!PACKET_get_net_2(&key_share_list, &group_id)
+                || !PACKET_get_length_prefixed_2(&key_share_list, &encoded_pt)
+                || PACKET_remaining(&encoded_pt) == 0) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                     SSL_R_LENGTH_MISMATCH);
+            return 0;
+        }
+
+        /*
+         * If we already found a suitable key_share we loop through the
+         * rest to verify the structure, but don't process them.
+         */
+        if (found)
+            continue;
+
+        /*
+         * If we sent an HRR then the key_share sent back MUST be for the group
+         * we requested, and must be the only key_share sent.
+         */
+        if (s->s3->group_id != 0
+                && (group_id != s->s3->group_id
+                    || PACKET_remaining(&key_share_list) != 0)) {
+            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                     SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
+            return 0;
+        }
+
+        /* Check if this share is in supported_groups sent from client */
+        if (!check_in_list(s, group_id, clntgroups, clnt_num_groups, 0)) {
+            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                     SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
+            return 0;
+        }
+
+        /* Check if this share is for a group we can use */
+        if (!check_in_list(s, group_id, srvrgroups, srvr_num_groups, 1)) {
+            /* Share not suitable */
+            continue;
+        }
+
+        if ((s->s3->peer_tmp = ssl_generate_param_group(group_id)) == NULL) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+                   SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
+            return 0;
+        }
+
+        s->s3->group_id = group_id;
+
+        if (!EVP_PKEY_set1_tls_encodedpoint(s->s3->peer_tmp,
+                PACKET_data(&encoded_pt),
+                PACKET_remaining(&encoded_pt))) {
+            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                     SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_ECPOINT);
+            return 0;
+        }
+
+        found = 1;
+    }
+#endif
+
+    return 1;
+}
+
+int tls_parse_ctos_cookie(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                          size_t chainidx)
+{
+#ifndef OPENSSL_NO_TLS1_3
+    unsigned int format, version, key_share, group_id;
+    EVP_MD_CTX *hctx;
+    EVP_PKEY *pkey;
+    PACKET cookie, raw, chhash, appcookie;
+    WPACKET hrrpkt;
+    const unsigned char *data, *mdin, *ciphdata;
+    unsigned char hmac[SHA256_DIGEST_LENGTH];
+    unsigned char hrr[MAX_HRR_SIZE];
+    size_t rawlen, hmaclen, hrrlen, ciphlen;
+    unsigned long tm, now;
+
+    /* Ignore any cookie if we're not set up to verify it */
+    if (s->ctx->verify_stateless_cookie_cb == NULL
+            || (s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
+        return 1;
+
+    if (!PACKET_as_length_prefixed_2(pkt, &cookie)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+
+    raw = cookie;
+    data = PACKET_data(&raw);
+    rawlen = PACKET_remaining(&raw);
+    if (rawlen < SHA256_DIGEST_LENGTH
+            || !PACKET_forward(&raw, rawlen - SHA256_DIGEST_LENGTH)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+    mdin = PACKET_data(&raw);
+
+    /* Verify the HMAC of the cookie */
+    hctx = EVP_MD_CTX_create();
+    pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
+                                        s->session_ctx->ext.cookie_hmac_key,
+                                        sizeof(s->session_ctx->ext
+                                               .cookie_hmac_key));
+    if (hctx == NULL || pkey == NULL) {
+        EVP_MD_CTX_free(hctx);
+        EVP_PKEY_free(pkey);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+
+    hmaclen = SHA256_DIGEST_LENGTH;
+    if (EVP_DigestSignInit(hctx, NULL, EVP_sha256(), NULL, pkey) <= 0
+            || EVP_DigestSign(hctx, hmac, &hmaclen, data,
+                              rawlen - SHA256_DIGEST_LENGTH) <= 0
+            || hmaclen != SHA256_DIGEST_LENGTH) {
+        EVP_MD_CTX_free(hctx);
+        EVP_PKEY_free(pkey);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    EVP_MD_CTX_free(hctx);
+    EVP_PKEY_free(pkey);
+
+    if (CRYPTO_memcmp(hmac, mdin, SHA256_DIGEST_LENGTH) != 0) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_COOKIE_MISMATCH);
+        return 0;
+    }
+
+    if (!PACKET_get_net_2(&cookie, &format)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+    /* Check the cookie format is something we recognise. Ignore it if not */
+    if (format != COOKIE_STATE_FORMAT_VERSION)
+        return 1;
+
+    /*
+     * The rest of these checks really shouldn't fail since we have verified the
+     * HMAC above.
+     */
+
+    /* Check the version number is sane */
+    if (!PACKET_get_net_2(&cookie, &version)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+    if (version != TLS1_3_VERSION) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
+        return 0;
+    }
+
+    if (!PACKET_get_net_2(&cookie, &group_id)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+
+    ciphdata = PACKET_data(&cookie);
+    if (!PACKET_forward(&cookie, 2)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+    if (group_id != s->s3->group_id
+            || s->s3->tmp.new_cipher
+               != ssl_get_cipher_by_char(s, ciphdata, 0)) {
+        /*
+         * We chose a different cipher or group id this time around to what is
+         * in the cookie. Something must have changed.
+         */
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_BAD_CIPHER);
+        return 0;
+    }
+
+    if (!PACKET_get_1(&cookie, &key_share)
+            || !PACKET_get_net_4(&cookie, &tm)
+            || !PACKET_get_length_prefixed_2(&cookie, &chhash)
+            || !PACKET_get_length_prefixed_1(&cookie, &appcookie)
+            || PACKET_remaining(&cookie) != SHA256_DIGEST_LENGTH) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+
+    /* We tolerate a cookie age of up to 10 minutes (= 60 * 10 seconds) */
+    now = (unsigned long)time(NULL);
+    if (tm > now || (now - tm) > 600) {
+        /* Cookie is stale. Ignore it */
+        return 1;
+    }
+
+    /* Verify the app cookie */
+    if (s->ctx->verify_stateless_cookie_cb(s, PACKET_data(&appcookie),
+                                     PACKET_remaining(&appcookie)) == 0) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 SSL_R_COOKIE_MISMATCH);
+        return 0;
+    }
+
+    /*
+     * Reconstruct the HRR that we would have sent in response to the original
+     * ClientHello so we can add it to the transcript hash.
+     * Note: This won't work with custom HRR extensions
+     */
+    if (!WPACKET_init_static_len(&hrrpkt, hrr, sizeof(hrr), 0)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+    if (!WPACKET_put_bytes_u8(&hrrpkt, SSL3_MT_SERVER_HELLO)
+            || !WPACKET_start_sub_packet_u24(&hrrpkt)
+            || !WPACKET_put_bytes_u16(&hrrpkt, TLS1_2_VERSION)
+            || !WPACKET_memcpy(&hrrpkt, hrrrandom, SSL3_RANDOM_SIZE)
+            || !WPACKET_sub_memcpy_u8(&hrrpkt, s->tmp_session_id,
+                                      s->tmp_session_id_len)
+            || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, &hrrpkt,
+                                              &ciphlen)
+            || !WPACKET_put_bytes_u8(&hrrpkt, 0)
+            || !WPACKET_start_sub_packet_u16(&hrrpkt)) {
+        WPACKET_cleanup(&hrrpkt);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+    if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_supported_versions)
+            || !WPACKET_start_sub_packet_u16(&hrrpkt)
+            || !WPACKET_put_bytes_u16(&hrrpkt, s->version)
+            || !WPACKET_close(&hrrpkt)) {
+        WPACKET_cleanup(&hrrpkt);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+    if (key_share) {
+        if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_key_share)
+                || !WPACKET_start_sub_packet_u16(&hrrpkt)
+                || !WPACKET_put_bytes_u16(&hrrpkt, s->s3->group_id)
+                || !WPACKET_close(&hrrpkt)) {
+            WPACKET_cleanup(&hrrpkt);
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                     ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+    }
+    if (!WPACKET_put_bytes_u16(&hrrpkt, TLSEXT_TYPE_cookie)
+            || !WPACKET_start_sub_packet_u16(&hrrpkt)
+            || !WPACKET_sub_memcpy_u16(&hrrpkt, data, rawlen)
+            || !WPACKET_close(&hrrpkt) /* cookie extension */
+            || !WPACKET_close(&hrrpkt) /* extension block */
+            || !WPACKET_close(&hrrpkt) /* message */
+            || !WPACKET_get_total_written(&hrrpkt, &hrrlen)
+            || !WPACKET_finish(&hrrpkt)) {
+        WPACKET_cleanup(&hrrpkt);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    /* Reconstruct the transcript hash */
+    if (!create_synthetic_message_hash(s, PACKET_data(&chhash),
+                                       PACKET_remaining(&chhash), hrr,
+                                       hrrlen)) {
+        /* SSLfatal() already called */
+        return 0;
+    }
+
+    /* Act as if this ClientHello came after a HelloRetryRequest */
+    s->hello_retry_request = 1;
+
+    s->ext.cookieok = 1;
+#endif
+
+    return 1;
+}
+
+#ifndef OPENSSL_NO_EC
+int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, unsigned int context,
+                                    X509 *x, size_t chainidx)
+{
+    PACKET supported_groups_list;
+
+    /* Each group is 2 bytes and we must have at least 1. */
+    if (!PACKET_as_length_prefixed_2(pkt, &supported_groups_list)
+            || PACKET_remaining(&supported_groups_list) == 0
+            || (PACKET_remaining(&supported_groups_list) % 2) != 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_SUPPORTED_GROUPS, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (!s->hit || SSL_IS_TLS13(s)) {
+        OPENSSL_free(s->ext.peer_supportedgroups);
+        s->ext.peer_supportedgroups = NULL;
+        s->ext.peer_supportedgroups_len = 0;
+        if (!tls1_save_u16(&supported_groups_list,
+                           &s->ext.peer_supportedgroups,
+                           &s->ext.peer_supportedgroups_len)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_SUPPORTED_GROUPS,
+                     ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+    }
+
+    return 1;
+}
+#endif
+
+int tls_parse_ctos_ems(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                       size_t chainidx)
+{
+    /* The extension must always be empty */
+    if (PACKET_remaining(pkt) != 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_EMS, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    s->s3->flags |= TLS1_FLAGS_RECEIVED_EXTMS;
+
+    return 1;
+}
+
+
+int tls_parse_ctos_early_data(SSL *s, PACKET *pkt, unsigned int context,
+                              X509 *x, size_t chainidx)
+{
+    if (PACKET_remaining(pkt) != 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_EARLY_DATA, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    if (s->hello_retry_request != SSL_HRR_NONE) {
+        SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                 SSL_F_TLS_PARSE_CTOS_EARLY_DATA, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    return 1;
+}
+
+static SSL_TICKET_STATUS tls_get_stateful_ticket(SSL *s, PACKET *tick,
+                                                 SSL_SESSION **sess)
+{
+    SSL_SESSION *tmpsess = NULL;
+
+    s->ext.ticket_expected = 1;
+
+    switch (PACKET_remaining(tick)) {
+        case 0:
+            return SSL_TICKET_EMPTY;
+
+        case SSL_MAX_SSL_SESSION_ID_LENGTH:
+            break;
+
+        default:
+            return SSL_TICKET_NO_DECRYPT;
+    }
+
+    tmpsess = lookup_sess_in_cache(s, PACKET_data(tick),
+                                   SSL_MAX_SSL_SESSION_ID_LENGTH);
+
+    if (tmpsess == NULL)
+        return SSL_TICKET_NO_DECRYPT;
+
+    *sess = tmpsess;
+    return SSL_TICKET_SUCCESS;
+}
+
+int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
+                       size_t chainidx)
+{
+    PACKET identities, binders, binder;
+    size_t binderoffset, hashsize;
+    SSL_SESSION *sess = NULL;
+    unsigned int id, i, ext = 0;
+    const EVP_MD *md = NULL;
+
+    /*
+     * If we have no PSK kex mode that we recognise then we can't resume so
+     * ignore this extension
+     */
+    if ((s->ext.psk_kex_mode
+            & (TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE)) == 0)
+        return 1;
+
+    if (!PACKET_get_length_prefixed_2(pkt, &identities)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR,
+                 SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
+        return 0;
+    }
+
+    s->ext.ticket_expected = 0;
+    for (id = 0; PACKET_remaining(&identities) != 0; id++) {
+        PACKET identity;
+        unsigned long ticket_agel;
+        size_t idlen;
+
+        if (!PACKET_get_length_prefixed_2(&identities, &identity)
+                || !PACKET_get_net_4(&identities, &ticket_agel)) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+        idlen = PACKET_remaining(&identity);
+        if (s->psk_find_session_cb != NULL
+                && !s->psk_find_session_cb(s, PACKET_data(&identity), idlen,
+                                           &sess)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_PARSE_CTOS_PSK, SSL_R_BAD_EXTENSION);
+            return 0;
+        }
+
+#ifndef OPENSSL_NO_PSK
+        if(sess == NULL
+                && s->psk_server_callback != NULL
+                && idlen <= PSK_MAX_IDENTITY_LEN) {
+            char *pskid = NULL;
+            unsigned char pskdata[PSK_MAX_PSK_LEN];
+            unsigned int pskdatalen;
+
+            if (!PACKET_strndup(&identity, &pskid)) {
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                         ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
+            pskdatalen = s->psk_server_callback(s, pskid, pskdata,
+                                                sizeof(pskdata));
+            OPENSSL_free(pskid);
+            if (pskdatalen > PSK_MAX_PSK_LEN) {
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                         ERR_R_INTERNAL_ERROR);
+                return 0;
+            } else if (pskdatalen > 0) {
+                const SSL_CIPHER *cipher;
+                const unsigned char tls13_aes128gcmsha256_id[] = { 0x13, 0x01 };
+
+                /*
+                 * We found a PSK using an old style callback. We don't know
+                 * the digest so we default to SHA256 as per the TLSv1.3 spec
+                 */
+                cipher = SSL_CIPHER_find(s, tls13_aes128gcmsha256_id);
+                if (cipher == NULL) {
+                    OPENSSL_cleanse(pskdata, pskdatalen);
+                    SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                             ERR_R_INTERNAL_ERROR);
+                    return 0;
+                }
+
+                sess = SSL_SESSION_new();
+                if (sess == NULL
+                        || !SSL_SESSION_set1_master_key(sess, pskdata,
+                                                        pskdatalen)
+                        || !SSL_SESSION_set_cipher(sess, cipher)
+                        || !SSL_SESSION_set_protocol_version(sess,
+                                                             TLS1_3_VERSION)) {
+                    OPENSSL_cleanse(pskdata, pskdatalen);
+                    SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                             ERR_R_INTERNAL_ERROR);
+                    goto err;
+                }
+                OPENSSL_cleanse(pskdata, pskdatalen);
+            }
+        }
+#endif /* OPENSSL_NO_PSK */
+
+        if (sess != NULL) {
+            /* We found a PSK */
+            SSL_SESSION *sesstmp = ssl_session_dup(sess, 0);
+
+            if (sesstmp == NULL) {
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
+            SSL_SESSION_free(sess);
+            sess = sesstmp;
+
+            /*
+             * We've just been told to use this session for this context so
+             * make sure the sid_ctx matches up.
+             */
+            memcpy(sess->sid_ctx, s->sid_ctx, s->sid_ctx_length);
+            sess->sid_ctx_length = s->sid_ctx_length;
+            ext = 1;
+            if (id == 0)
+                s->ext.early_data_ok = 1;
+            s->ext.ticket_expected = 1;
+        } else {
+            uint32_t ticket_age = 0, now, agesec, agems;
+            int ret;
+
+            /*
+             * If we are using anti-replay protection then we behave as if
+             * SSL_OP_NO_TICKET is set - we are caching tickets anyway so there
+             * is no point in using full stateless tickets.
+             */
+            if ((s->options & SSL_OP_NO_TICKET) != 0
+                    || (s->max_early_data > 0
+                        && (s->options & SSL_OP_NO_ANTI_REPLAY) == 0))
+                ret = tls_get_stateful_ticket(s, &identity, &sess);
+            else
+                ret = tls_decrypt_ticket(s, PACKET_data(&identity),
+                                         PACKET_remaining(&identity), NULL, 0,
+                                         &sess);
+
+            if (ret == SSL_TICKET_EMPTY) {
+                SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                         SSL_R_BAD_EXTENSION);
+                return 0;
+            }
+
+            if (ret == SSL_TICKET_FATAL_ERR_MALLOC
+                    || ret == SSL_TICKET_FATAL_ERR_OTHER) {
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                         SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
+            if (ret == SSL_TICKET_NONE || ret == SSL_TICKET_NO_DECRYPT)
+                continue;
+
+            /* Check for replay */
+            if (s->max_early_data > 0
+                    && (s->options & SSL_OP_NO_ANTI_REPLAY) == 0
+                    && !SSL_CTX_remove_session(s->session_ctx, sess)) {
+                SSL_SESSION_free(sess);
+                sess = NULL;
+                continue;
+            }
+
+            ticket_age = (uint32_t)ticket_agel;
+            now = (uint32_t)time(NULL);
+            agesec = now - (uint32_t)sess->time;
+            agems = agesec * (uint32_t)1000;
+            ticket_age -= sess->ext.tick_age_add;
+
+            /*
+             * For simplicity we do our age calculations in seconds. If the
+             * client does it in ms then it could appear that their ticket age
+             * is longer than ours (our ticket age calculation should always be
+             * slightly longer than the client's due to the network latency).
+             * Therefore we add 1000ms to our age calculation to adjust for
+             * rounding errors.
+             */
+            if (id == 0
+                    && sess->timeout >= (long)agesec
+                    && agems / (uint32_t)1000 == agesec
+                    && ticket_age <= agems + 1000
+                    && ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
+                /*
+                 * Ticket age is within tolerance and not expired. We allow it
+                 * for early data
+                 */
+                s->ext.early_data_ok = 1;
+            }
+        }
+
+        md = ssl_md(sess->cipher->algorithm2);
+        if (md != ssl_md(s->s3->tmp.new_cipher->algorithm2)) {
+            /* The ciphersuite is not compatible with this session. */
+            SSL_SESSION_free(sess);
+            sess = NULL;
+            s->ext.early_data_ok = 0;
+            s->ext.ticket_expected = 0;
+            continue;
+        }
+        break;
+    }
+
+    if (sess == NULL)
+        return 1;
+
+    binderoffset = PACKET_data(pkt) - (const unsigned char *)s->init_buf->data;
+    hashsize = EVP_MD_size(md);
+
+    if (!PACKET_get_length_prefixed_2(pkt, &binders)) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                 SSL_R_BAD_EXTENSION);
+        goto err;
+    }
+
+    for (i = 0; i <= id; i++) {
+        if (!PACKET_get_length_prefixed_1(&binders, &binder)) {
+            SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                     SSL_R_BAD_EXTENSION);
+            goto err;
+        }
+    }
+
+    if (PACKET_remaining(&binder) != hashsize) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_PSK,
+                 SSL_R_BAD_EXTENSION);
+        goto err;
+    }
+    if (tls_psk_do_binder(s, md, (const unsigned char *)s->init_buf->data,
+                          binderoffset, PACKET_data(&binder), NULL, sess, 0,
+                          ext) != 1) {
+        /* SSLfatal() already called */
+        goto err;
+    }
+
+    s->ext.tick_identity = id;
+
+    SSL_SESSION_free(s->session);
+    s->session = sess;
+    return 1;
+err:
+    SSL_SESSION_free(sess);
+    return 0;
+}
+
+int tls_parse_ctos_post_handshake_auth(SSL *s, PACKET *pkt, unsigned int context,
+                                       X509 *x, size_t chainidx)
+{
+    if (PACKET_remaining(pkt) != 0) {
+        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PARSE_CTOS_POST_HANDSHAKE_AUTH,
+                 SSL_R_POST_HANDSHAKE_AUTH_ENCODING_ERR);
+        return 0;
+    }
+
+    s->post_handshake_auth = SSL_PHA_EXT_RECEIVED;
+
+    return 1;
+}
+
+/*
+ * Add the server's renegotiation binding
+ */
+EXT_RETURN tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx)
+{
+    if (!s->s3->send_connection_binding)
+        return EXT_RETURN_NOT_SENT;
+
+    /* Still add this even if SSL_OP_NO_RENEGOTIATION is set */
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_start_sub_packet_u8(pkt)
+            || !WPACKET_memcpy(pkt, s->s3->previous_client_finished,
+                               s->s3->previous_client_finished_len)
+            || !WPACKET_memcpy(pkt, s->s3->previous_server_finished,
+                               s->s3->previous_server_finished_len)
+            || !WPACKET_close(pkt)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_RENEGOTIATE,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_server_name(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx)
+{
+    if (s->servername_done != 1)
+        return EXT_RETURN_NOT_SENT;
+
+    /*
+     * Prior to TLSv1.3 we ignore any SNI in the current handshake if resuming.
+     * We just use the servername from the initial handshake.
+     */
+    if (s->hit && !SSL_IS_TLS13(s))
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
+            || !WPACKET_put_bytes_u16(pkt, 0)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_SERVER_NAME,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+/* Add/include the server's max fragment len extension into ServerHello */
+EXT_RETURN tls_construct_stoc_maxfragmentlen(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx)
+{
+    if (!USE_MAX_FRAGMENT_LENGTH_EXT(s->session))
+        return EXT_RETURN_NOT_SENT;
+
+    /*-
+     * 4 bytes for this extension type and extension length
+     * 1 byte for the Max Fragment Length code value.
+     */
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_max_fragment_length)
+        || !WPACKET_start_sub_packet_u16(pkt)
+        || !WPACKET_put_bytes_u8(pkt, s->session->ext.max_fragment_len_mode)
+        || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_MAXFRAGMENTLEN, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+#ifndef OPENSSL_NO_EC
+EXT_RETURN tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx)
+{
+    unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
+    unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
+    int using_ecc = ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))
+                    && (s->ext.peer_ecpointformats != NULL);
+    const unsigned char *plist;
+    size_t plistlen;
+
+    if (!using_ecc)
+        return EXT_RETURN_NOT_SENT;
+
+    tls1_get_formatlist(s, &plist, &plistlen);
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_ec_point_formats)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_sub_memcpy_u8(pkt, plist, plistlen)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+#endif
+
+#ifndef OPENSSL_NO_EC
+EXT_RETURN tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
+                                               unsigned int context, X509 *x,
+                                               size_t chainidx)
+{
+    const uint16_t *groups;
+    size_t numgroups, i, first = 1;
+
+    /* s->s3->group_id is non zero if we accepted a key_share */
+    if (s->s3->group_id == 0)
+        return EXT_RETURN_NOT_SENT;
+
+    /* Get our list of supported groups */
+    tls1_get_supported_groups(s, &groups, &numgroups);
+    if (numgroups == 0) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    /* Copy group ID if supported */
+    for (i = 0; i < numgroups; i++) {
+        uint16_t group = groups[i];
+
+        if (tls_curve_allowed(s, group, SSL_SECOP_CURVE_SUPPORTED)) {
+            if (first) {
+                /*
+                 * Check if the client is already using our preferred group. If
+                 * so we don't need to add this extension
+                 */
+                if (s->s3->group_id == group)
+                    return EXT_RETURN_NOT_SENT;
+
+                /* Add extension header */
+                if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
+                           /* Sub-packet for supported_groups extension */
+                        || !WPACKET_start_sub_packet_u16(pkt)
+                        || !WPACKET_start_sub_packet_u16(pkt)) {
+                    SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                             SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
+                             ERR_R_INTERNAL_ERROR);
+                    return EXT_RETURN_FAIL;
+                }
+
+                first = 0;
+            }
+            if (!WPACKET_put_bytes_u16(pkt, group)) {
+                    SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                             SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
+                             ERR_R_INTERNAL_ERROR);
+                    return EXT_RETURN_FAIL;
+                }
+        }
+    }
+
+    if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+#endif
+
+EXT_RETURN tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx)
+{
+    if (!s->ext.ticket_expected || !tls_use_ticket(s)) {
+        s->ext.ticket_expected = 0;
+        return EXT_RETURN_NOT_SENT;
+    }
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
+            || !WPACKET_put_bytes_u16(pkt, 0)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+#ifndef OPENSSL_NO_OCSP
+EXT_RETURN tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx)
+{
+    /* We don't currently support this extension inside a CertificateRequest */
+    if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!s->ext.status_expected)
+        return EXT_RETURN_NOT_SENT;
+
+    if (SSL_IS_TLS13(s) && chainidx != 0)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
+            || !WPACKET_start_sub_packet_u16(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    /*
+     * In TLSv1.3 we include the certificate status itself. In <= TLSv1.2 we
+     * send back an empty extension, with the certificate status appearing as a
+     * separate message
+     */
+    if (SSL_IS_TLS13(s) && !tls_construct_cert_status_body(s, pkt)) {
+       /* SSLfatal() already called */
+       return EXT_RETURN_FAIL;
+    }
+    if (!WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+#endif
+
+#ifndef OPENSSL_NO_NEXTPROTONEG
+EXT_RETURN tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx)
+{
+    const unsigned char *npa;
+    unsigned int npalen;
+    int ret;
+    int npn_seen = s->s3->npn_seen;
+
+    s->s3->npn_seen = 0;
+    if (!npn_seen || s->ctx->ext.npn_advertised_cb == NULL)
+        return EXT_RETURN_NOT_SENT;
+
+    ret = s->ctx->ext.npn_advertised_cb(s, &npa, &npalen,
+                                        s->ctx->ext.npn_advertised_cb_arg);
+    if (ret == SSL_TLSEXT_ERR_OK) {
+        if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_next_proto_neg)
+                || !WPACKET_sub_memcpy_u16(pkt, npa, npalen)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_CONSTRUCT_STOC_NEXT_PROTO_NEG,
+                     ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+        s->s3->npn_seen = 1;
+    }
+
+    return EXT_RETURN_SENT;
+}
+#endif
+
+EXT_RETURN tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, unsigned int context,
+                                   X509 *x, size_t chainidx)
+{
+    if (s->s3->alpn_selected == NULL)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt,
+                TLSEXT_TYPE_application_layer_protocol_negotiation)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_sub_memcpy_u8(pkt, s->s3->alpn_selected,
+                                      s->s3->alpn_selected_len)
+            || !WPACKET_close(pkt)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_ALPN, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+#ifndef OPENSSL_NO_SRTP
+EXT_RETURN tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt,
+                                       unsigned int context, X509 *x,
+                                       size_t chainidx)
+{
+    if (s->srtp_profile == NULL)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_put_bytes_u16(pkt, 2)
+            || !WPACKET_put_bytes_u16(pkt, s->srtp_profile->id)
+            || !WPACKET_put_bytes_u8(pkt, 0)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_USE_SRTP,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+#endif
+
+EXT_RETURN tls_construct_stoc_etm(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    if (!s->ext.use_etm)
+        return EXT_RETURN_NOT_SENT;
+
+    /*
+     * Don't use encrypt_then_mac if AEAD or RC4 might want to disable
+     * for other cases too.
+     */
+    if (s->s3->tmp.new_cipher->algorithm_mac == SSL_AEAD
+        || s->s3->tmp.new_cipher->algorithm_enc == SSL_RC4
+        || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT
+        || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT12) {
+        s->ext.use_etm = 0;
+        return EXT_RETURN_NOT_SENT;
+    }
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_encrypt_then_mac)
+            || !WPACKET_put_bytes_u16(pkt, 0)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_ETM,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_ems(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    if ((s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) == 0)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
+            || !WPACKET_put_bytes_u16(pkt, 0)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_EMS,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_supported_versions(SSL *s, WPACKET *pkt,
+                                                 unsigned int context, X509 *x,
+                                                 size_t chainidx)
+{
+    if (!ossl_assert(SSL_IS_TLS13(s))) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_VERSIONS,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_versions)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_put_bytes_u16(pkt, s->version)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_VERSIONS,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_key_share(SSL *s, WPACKET *pkt,
+                                        unsigned int context, X509 *x,
+                                        size_t chainidx)
+{
+#ifndef OPENSSL_NO_TLS1_3
+    unsigned char *encodedPoint;
+    size_t encoded_pt_len = 0;
+    EVP_PKEY *ckey = s->s3->peer_tmp, *skey = NULL;
+
+    if (s->hello_retry_request == SSL_HRR_PENDING) {
+        if (ckey != NULL) {
+            /* Original key_share was acceptable so don't ask for another one */
+            return EXT_RETURN_NOT_SENT;
+        }
+        if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
+                || !WPACKET_start_sub_packet_u16(pkt)
+                || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)
+                || !WPACKET_close(pkt)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
+                     ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+
+        return EXT_RETURN_SENT;
+    }
+
+    if (ckey == NULL) {
+        /* No key_share received from client - must be resuming */
+        if (!s->hit || !tls13_generate_handshake_secret(s, NULL, 0)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+        return EXT_RETURN_NOT_SENT;
+    }
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    skey = ssl_generate_pkey(ckey);
+    if (skey == NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
+                 ERR_R_MALLOC_FAILURE);
+        return EXT_RETURN_FAIL;
+    }
+
+    /* Generate encoding of server key */
+    encoded_pt_len = EVP_PKEY_get1_tls_encodedpoint(skey, &encodedPoint);
+    if (encoded_pt_len == 0) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
+                 ERR_R_EC_LIB);
+        EVP_PKEY_free(skey);
+        return EXT_RETURN_FAIL;
+    }
+
+    if (!WPACKET_sub_memcpy_u16(pkt, encodedPoint, encoded_pt_len)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
+                 ERR_R_INTERNAL_ERROR);
+        EVP_PKEY_free(skey);
+        OPENSSL_free(encodedPoint);
+        return EXT_RETURN_FAIL;
+    }
+    OPENSSL_free(encodedPoint);
+
+    /* This causes the crypto state to be updated based on the derived keys */
+    s->s3->tmp.pkey = skey;
+    if (ssl_derive(s, skey, ckey, 1) == 0) {
+        /* SSLfatal() already called */
+        return EXT_RETURN_FAIL;
+    }
+    return EXT_RETURN_SENT;
+#else
+    return EXT_RETURN_FAIL;
+#endif
+}
+
+EXT_RETURN tls_construct_stoc_cookie(SSL *s, WPACKET *pkt, unsigned int context,
+                                     X509 *x, size_t chainidx)
+{
+#ifndef OPENSSL_NO_TLS1_3
+    unsigned char *hashval1, *hashval2, *appcookie1, *appcookie2, *cookie;
+    unsigned char *hmac, *hmac2;
+    size_t startlen, ciphlen, totcookielen, hashlen, hmaclen, appcookielen;
+    EVP_MD_CTX *hctx;
+    EVP_PKEY *pkey;
+    int ret = EXT_RETURN_FAIL;
+
+    if ((s->s3->flags & TLS1_FLAGS_STATELESS) == 0)
+        return EXT_RETURN_NOT_SENT;
+
+    if (s->ctx->gen_stateless_cookie_cb == NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 SSL_R_NO_COOKIE_CALLBACK_SET);
+        return EXT_RETURN_FAIL;
+    }
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_cookie)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_get_total_written(pkt, &startlen)
+            || !WPACKET_reserve_bytes(pkt, MAX_COOKIE_SIZE, &cookie)
+            || !WPACKET_put_bytes_u16(pkt, COOKIE_STATE_FORMAT_VERSION)
+            || !WPACKET_put_bytes_u16(pkt, TLS1_3_VERSION)
+            || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)
+            || !s->method->put_cipher_by_char(s->s3->tmp.new_cipher, pkt,
+                                              &ciphlen)
+               /* Is there a key_share extension present in this HRR? */
+            || !WPACKET_put_bytes_u8(pkt, s->s3->peer_tmp == NULL)
+            || !WPACKET_put_bytes_u32(pkt, (unsigned int)time(NULL))
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_reserve_bytes(pkt, EVP_MAX_MD_SIZE, &hashval1)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    /*
+     * Get the hash of the initial ClientHello. ssl_handshake_hash() operates
+     * on raw buffers, so we first reserve sufficient bytes (above) and then
+     * subsequently allocate them (below)
+     */
+    if (!ssl3_digest_cached_records(s, 0)
+            || !ssl_handshake_hash(s, hashval1, EVP_MAX_MD_SIZE, &hashlen)) {
+        /* SSLfatal() already called */
+        return EXT_RETURN_FAIL;
+    }
+
+    if (!WPACKET_allocate_bytes(pkt, hashlen, &hashval2)
+            || !ossl_assert(hashval1 == hashval2)
+            || !WPACKET_close(pkt)
+            || !WPACKET_start_sub_packet_u8(pkt)
+            || !WPACKET_reserve_bytes(pkt, SSL_COOKIE_LENGTH, &appcookie1)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    /* Generate the application cookie */
+    if (s->ctx->gen_stateless_cookie_cb(s, appcookie1, &appcookielen) == 0) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
+        return EXT_RETURN_FAIL;
+    }
+
+    if (!WPACKET_allocate_bytes(pkt, appcookielen, &appcookie2)
+            || !ossl_assert(appcookie1 == appcookie2)
+            || !WPACKET_close(pkt)
+            || !WPACKET_get_total_written(pkt, &totcookielen)
+            || !WPACKET_reserve_bytes(pkt, SHA256_DIGEST_LENGTH, &hmac)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+    hmaclen = SHA256_DIGEST_LENGTH;
+
+    totcookielen -= startlen;
+    if (!ossl_assert(totcookielen <= MAX_COOKIE_SIZE - SHA256_DIGEST_LENGTH)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    /* HMAC the cookie */
+    hctx = EVP_MD_CTX_create();
+    pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL,
+                                        s->session_ctx->ext.cookie_hmac_key,
+                                        sizeof(s->session_ctx->ext
+                                               .cookie_hmac_key));
+    if (hctx == NULL || pkey == NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    if (EVP_DigestSignInit(hctx, NULL, EVP_sha256(), NULL, pkey) <= 0
+            || EVP_DigestSign(hctx, hmac, &hmaclen, cookie,
+                              totcookielen) <= 0) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (!ossl_assert(totcookielen + hmaclen <= MAX_COOKIE_SIZE)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (!WPACKET_allocate_bytes(pkt, hmaclen, &hmac2)
+            || !ossl_assert(hmac == hmac2)
+            || !ossl_assert(cookie == hmac - totcookielen)
+            || !WPACKET_close(pkt)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_COOKIE,
+                 ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    ret = EXT_RETURN_SENT;
+
+ err:
+    EVP_MD_CTX_free(hctx);
+    EVP_PKEY_free(pkey);
+    return ret;
+#else
+    return EXT_RETURN_FAIL;
+#endif
+}
+
+EXT_RETURN tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx)
+{
+    const unsigned char cryptopro_ext[36] = {
+        0xfd, 0xe8,         /* 65000 */
+        0x00, 0x20,         /* 32 bytes length */
+        0x30, 0x1e, 0x30, 0x08, 0x06, 0x06, 0x2a, 0x85,
+        0x03, 0x02, 0x02, 0x09, 0x30, 0x08, 0x06, 0x06,
+        0x2a, 0x85, 0x03, 0x02, 0x02, 0x16, 0x30, 0x08,
+        0x06, 0x06, 0x2a, 0x85, 0x03, 0x02, 0x02, 0x17
+    };
+
+    if (((s->s3->tmp.new_cipher->id & 0xFFFF) != 0x80
+         && (s->s3->tmp.new_cipher->id & 0xFFFF) != 0x81)
+            || (SSL_get_options(s) & SSL_OP_CRYPTOPRO_TLSEXT_BUG) == 0)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_memcpy(pkt, cryptopro_ext, sizeof(cryptopro_ext))) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_CRYPTOPRO_BUG, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_early_data(SSL *s, WPACKET *pkt,
+                                         unsigned int context, X509 *x,
+                                         size_t chainidx)
+{
+    if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
+        if (s->max_early_data == 0)
+            return EXT_RETURN_NOT_SENT;
+
+        if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
+                || !WPACKET_start_sub_packet_u16(pkt)
+                || !WPACKET_put_bytes_u32(pkt, s->max_early_data)
+                || !WPACKET_close(pkt)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA, ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+
+        return EXT_RETURN_SENT;
+    }
+
+    if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA,
+                 ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}
+
+EXT_RETURN tls_construct_stoc_psk(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx)
+{
+    if (!s->hit)
+        return EXT_RETURN_NOT_SENT;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_put_bytes_u16(pkt, s->ext.tick_identity)
+            || !WPACKET_close(pkt)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS_CONSTRUCT_STOC_PSK, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
+}