Fix some style issues identified during review
[openssl.git] / ssl / statem / statem_srvr.c
index 46bd5c7be02fd78766b6de151c3fea856b193660..33808ed9f488dc6d1953bea2096c7fdb29f67217 100644 (file)
@@ -68,19 +68,94 @@ static STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,
                                                       int *al);
 
 /*
- * server_read_transition() encapsulates the logic for the allowed handshake
- * state transitions when the server is reading messages from the client. The
- * message type that the client has sent is provided in |mt|. The current state
- * is in |s->statem.hand_state|.
+ * ossl_statem_server13_read_transition() encapsulates the logic for the allowed
+ * handshake state transitions when a TLSv1.3 server is reading messages from
+ * the client. The message type that the client has sent is provided in |mt|.
+ * The current state is in |s->statem.hand_state|.
  *
- *  Valid return values are:
- *  1: Success (transition allowed)
- *  0: Error (transition not allowed)
+ * Return values are 1 for success (transition allowed) and  0 on error
+ * (transition not allowed)
+ */
+static int ossl_statem_server13_read_transition(SSL *s, int mt)
+{
+    OSSL_STATEM *st = &s->statem;
+
+    /*
+     * TODO(TLS1.3): This is still based on the TLSv1.2 state machine. Over time
+     * we will update this to look more like real TLSv1.3
+     */
+
+    /*
+     * Note: There is no case for TLS_ST_BEFORE because at that stage we have
+     * not negotiated TLSv1.3 yet, so that case is handled by
+     * ossl_statem_server_read_transition()
+     */
+    switch (st->hand_state) {
+    default:
+        break;
+
+    case TLS_ST_SW_FINISHED:
+        if (s->s3->tmp.cert_request) {
+            if (mt == SSL3_MT_CERTIFICATE) {
+                st->hand_state = TLS_ST_SR_CERT;
+                return 1;
+            }
+        } else {
+            if (mt == SSL3_MT_FINISHED) {
+                st->hand_state = TLS_ST_SR_FINISHED;
+                return 1;
+            }
+        }
+        break;
+
+    case TLS_ST_SR_CERT:
+        if (s->session->peer == NULL) {
+            if (mt == SSL3_MT_FINISHED) {
+                st->hand_state = TLS_ST_SR_FINISHED;
+                return 1;
+            }
+        } else {
+            if (mt == SSL3_MT_CERTIFICATE_VERIFY) {
+                st->hand_state = TLS_ST_SR_CERT_VRFY;
+                return 1;
+            }
+        }
+        break;
+
+    case TLS_ST_SR_CERT_VRFY:
+        if (mt == SSL3_MT_FINISHED) {
+            st->hand_state = TLS_ST_SR_FINISHED;
+            return 1;
+        }
+        break;
+    }
+
+    /* No valid transition found */
+    ssl3_send_alert(s, SSL3_AL_FATAL, SSL3_AD_UNEXPECTED_MESSAGE);
+    SSLerr(SSL_F_OSSL_STATEM_SERVER13_READ_TRANSITION,
+           SSL_R_UNEXPECTED_MESSAGE);
+    return 0;
+}
+
+/*
+ * ossl_statem_server_read_transition() encapsulates the logic for the allowed
+ * handshake state transitions when the server is reading messages from the
+ * client. The message type that the client has sent is provided in |mt|. The
+ * current state is in |s->statem.hand_state|.
+ *
+ * Return values are 1 for success (transition allowed) and  0 on error
+ * (transition not allowed)
  */
 int ossl_statem_server_read_transition(SSL *s, int mt)
 {
     OSSL_STATEM *st = &s->statem;
 
+    if (SSL_IS_TLS13(s)) {
+        if (!ossl_statem_server13_read_transition(s, mt))
+            goto err;
+        return 1;
+    }
+
     switch (st->hand_state) {
     default:
         break;
@@ -212,6 +287,7 @@ int ossl_statem_server_read_transition(SSL *s, int mt)
         break;
     }
 
+ err:
     /* No valid transition found */
     ssl3_send_alert(s, SSL3_AL_FATAL, SSL3_AD_UNEXPECTED_MESSAGE);
     SSLerr(SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION, SSL_R_UNEXPECTED_MESSAGE);
@@ -304,13 +380,82 @@ static int send_certificate_request(SSL *s)
 }
 
 /*
- * server_write_transition() works out what handshake state to move to next
- * when the server is writing messages to be sent to the client.
+ * ossl_statem_server13_write_transition() works out what handshake state to
+ * move to next when a TLSv1.3 server is writing messages to be sent to the
+ * client.
+ */
+static WRITE_TRAN ossl_statem_server13_write_transition(SSL *s)
+{
+    OSSL_STATEM *st = &s->statem;
+
+    /*
+     * TODO(TLS1.3): This is still based on the TLSv1.2 state machine. Over time
+     * we will update this to look more like real TLSv1.3
+     */
+
+    /*
+     * No case for TLS_ST_BEFORE, because at that stage we have not negotiated
+     * TLSv1.3 yet, so that is handled by ossl_statem_server_write_transition()
+     */
+
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return WRITE_TRAN_ERROR;
+
+    case TLS_ST_SR_CLNT_HELLO:
+        st->hand_state = TLS_ST_SW_SRVR_HELLO;
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_SW_SRVR_HELLO:
+        if (s->hit)
+            st->hand_state = TLS_ST_SW_FINISHED;
+        else if (send_certificate_request(s))
+            st->hand_state = TLS_ST_SW_CERT_REQ;
+        else
+            st->hand_state = TLS_ST_SW_CERT;
+
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_SW_CERT_REQ:
+        st->hand_state = TLS_ST_SW_CERT;
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_SW_CERT:
+            st->hand_state = s->tlsext_status_expected ? TLS_ST_SW_CERT_STATUS
+                                                       : TLS_ST_SW_FINISHED;
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_SW_CERT_STATUS:
+        st->hand_state = TLS_ST_SW_FINISHED;
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_SW_FINISHED:
+        return WRITE_TRAN_FINISHED;
+
+    case TLS_ST_SR_FINISHED:
+        st->hand_state = TLS_ST_OK;
+        ossl_statem_set_in_init(s, 0);
+        return WRITE_TRAN_CONTINUE;
+    }
+}
+
+/*
+ * ossl_statem_server_write_transition() works out what handshake state to move
+ * to next when the server is writing messages to be sent to the client.
  */
 WRITE_TRAN ossl_statem_server_write_transition(SSL *s)
 {
     OSSL_STATEM *st = &s->statem;
 
+    /*
+     * Note that before the ClientHello we don't know what version we are going
+     * to negotiate yet, so we don't take this branch until later
+     */
+
+    if (SSL_IS_TLS13(s))
+        return ossl_statem_server13_write_transition(s);
+
     switch (st->hand_state) {
     default:
         /* Shouldn't happen */
@@ -564,6 +709,20 @@ WORK_STATE ossl_statem_server_post_work(SSL *s, WORK_STATE wst)
                      sizeof(sctpauthkey), sctpauthkey);
         }
 #endif
+        /*
+         * TODO(TLS1.3): This actually causes a problem. We don't yet know
+         * whether the next record we are going to receive is an unencrypted
+         * alert, or an encrypted handshake message. We're going to need
+         * something clever in the record layer for this.
+         */
+        if (SSL_IS_TLS13(s)) {
+            if (!s->method->ssl3_enc->setup_key_block(s)
+                || !s->method->ssl3_enc->change_cipher_state(s,
+                        SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_SERVER_WRITE)
+                || !s->method->ssl3_enc->change_cipher_state(s,
+                        SSL3_CC_HANDSHAKE |SSL3_CHANGE_CIPHER_SERVER_READ))
+            return WORK_ERROR;
+        }
         break;
 
     case TLS_ST_SW_CHANGE:
@@ -606,6 +765,14 @@ WORK_STATE ossl_statem_server_post_work(SSL *s, WORK_STATE wst)
                      0, NULL);
         }
 #endif
+        if (SSL_IS_TLS13(s)) {
+            if (!s->method->ssl3_enc->generate_master_secret(s,
+                        s->session->master_key, s->handshake_secret, 0,
+                        &s->session->master_key_length)
+                || !s->method->ssl3_enc->change_cipher_state(s,
+                        SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_SERVER_WRITE))
+            return WORK_ERROR;
+        }
         break;
     }
 
@@ -613,99 +780,83 @@ WORK_STATE ossl_statem_server_post_work(SSL *s, WORK_STATE wst)
 }
 
 /*
- * Construct a message to be sent from the server to the client.
+ * Get the message construction function and message type for sending from the
+ * server
  *
  * Valid return values are:
  *   1: Success
  *   0: Error
  */
-int ossl_statem_server_construct_message(SSL *s, WPACKET *pkt)
+int ossl_statem_server_construct_message(SSL *s, WPACKET *pkt,
+                                         confunc_f *confunc, int *mt)
 {
     OSSL_STATEM *st = &s->statem;
-    int (*confunc) (SSL *s, WPACKET *pkt) = NULL;
-    int ret = 1, mt;
-
-    if (st->hand_state == TLS_ST_SW_CHANGE) {
-        /* Special case becase it is a different content type */
-        if (SSL_IS_DTLS(s))
-            return dtls_construct_change_cipher_spec(s, pkt);
 
-        return tls_construct_change_cipher_spec(s, pkt);
-    } else if (st->hand_state == DTLS_ST_SW_HELLO_VERIFY_REQUEST) {
-        /* Special case because we don't call ssl_close_construct_packet() */
-        return dtls_construct_hello_verify_request(s, pkt);
-    } else {
-        switch (st->hand_state) {
-        default:
-            /* Shouldn't happen */
-            return 0;
-
-        case TLS_ST_SW_HELLO_REQ:
-            /* No construction function needed */
-            mt = SSL3_MT_HELLO_REQUEST;
-            break;
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return 0;
 
-        case TLS_ST_SW_SRVR_HELLO:
-            confunc = tls_construct_server_hello;
-            mt = SSL3_MT_SERVER_HELLO;
-            break;
+    case TLS_ST_SW_CHANGE:
+        if (SSL_IS_DTLS(s))
+            *confunc = dtls_construct_change_cipher_spec;
+        else
+            *confunc = tls_construct_change_cipher_spec;
+        *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
+        break;
 
-        case TLS_ST_SW_CERT:
-            confunc = tls_construct_server_certificate;
-            mt = SSL3_MT_CERTIFICATE;
-            break;
+    case DTLS_ST_SW_HELLO_VERIFY_REQUEST:
+        *confunc = dtls_construct_hello_verify_request;
+        *mt = DTLS1_MT_HELLO_VERIFY_REQUEST;
+        break;
 
-        case TLS_ST_SW_KEY_EXCH:
-            confunc = tls_construct_server_key_exchange;
-            mt = SSL3_MT_SERVER_KEY_EXCHANGE;
-            break;
+    case TLS_ST_SW_HELLO_REQ:
+        /* No construction function needed */
+        *confunc = NULL;
+        *mt = SSL3_MT_HELLO_REQUEST;
+        break;
 
-        case TLS_ST_SW_CERT_REQ:
-            confunc = tls_construct_certificate_request;
-            mt = SSL3_MT_CERTIFICATE_REQUEST;
-            break;
+    case TLS_ST_SW_SRVR_HELLO:
+        *confunc = tls_construct_server_hello;
+        *mt = SSL3_MT_SERVER_HELLO;
+        break;
 
-        case TLS_ST_SW_SRVR_DONE:
-            confunc = tls_construct_server_done;
-            mt = SSL3_MT_SERVER_DONE;
-            break;
+    case TLS_ST_SW_CERT:
+        *confunc = tls_construct_server_certificate;
+        *mt = SSL3_MT_CERTIFICATE;
+        break;
 
-        case TLS_ST_SW_SESSION_TICKET:
-            confunc = tls_construct_new_session_ticket;
-            mt = SSL3_MT_NEWSESSION_TICKET;
-            break;
+    case TLS_ST_SW_KEY_EXCH:
+        *confunc = tls_construct_server_key_exchange;
+        *mt = SSL3_MT_SERVER_KEY_EXCHANGE;
+        break;
 
-        case TLS_ST_SW_CERT_STATUS:
-            confunc = tls_construct_cert_status;
-            mt = SSL3_MT_CERTIFICATE_STATUS;
-            break;
+    case TLS_ST_SW_CERT_REQ:
+        *confunc = tls_construct_certificate_request;
+        *mt = SSL3_MT_CERTIFICATE_REQUEST;
+        break;
 
-        case TLS_ST_SW_FINISHED:
-            mt = SSL3_MT_FINISHED;
-            break;
-        }
+    case TLS_ST_SW_SRVR_DONE:
+        *confunc = tls_construct_server_done;
+        *mt = SSL3_MT_SERVER_DONE;
+        break;
 
-        if (!ssl_set_handshake_header(s, pkt, mt)) {
-            SSLerr(SSL_F_OSSL_STATEM_SERVER_CONSTRUCT_MESSAGE,
-                   ERR_R_INTERNAL_ERROR);
-            return 0;
-        }
+    case TLS_ST_SW_SESSION_TICKET:
+        *confunc = tls_construct_new_session_ticket;
+        *mt = SSL3_MT_NEWSESSION_TICKET;
+        break;
 
-        if (st->hand_state == TLS_ST_SW_FINISHED)
-            ret = tls_construct_finished(s, pkt,
-                                         s->method->
-                                         ssl3_enc->server_finished_label,
-                                         s->method->
-                                         ssl3_enc->server_finished_label_len);
-        else if (confunc != NULL)
-            ret = confunc(s, pkt);
+    case TLS_ST_SW_CERT_STATUS:
+        *confunc = tls_construct_cert_status;
+        *mt = SSL3_MT_CERTIFICATE_STATUS;
+        break;
 
-        if (!ret || !ssl_close_construct_packet(s, pkt)) {
-            SSLerr(SSL_F_OSSL_STATEM_SERVER_CONSTRUCT_MESSAGE,
-                   ERR_R_INTERNAL_ERROR);
-            return 0;
-        }
+    case TLS_ST_SW_FINISHED:
+        *confunc = tls_construct_finished;
+        *mt = SSL3_MT_FINISHED;
+        break;
     }
+
     return 1;
 }
 
@@ -733,7 +884,7 @@ int ossl_statem_server_construct_message(SSL *s, WPACKET *pkt)
  * Returns the maximum allowed length for the current message that we are
  * reading. Excludes the message header.
  */
-unsigned long ossl_statem_server_max_message_size(SSL *s)
+size_t ossl_statem_server_max_message_size(SSL *s)
 {
     OSSL_STATEM *st = &s->statem;
 
@@ -841,7 +992,7 @@ WORK_STATE ossl_statem_server_post_process_message(SSL *s, WORK_STATE wst)
 #endif
         return WORK_FINISHED_CONTINUE;
     }
-
+    return WORK_FINISHED_CONTINUE;
 }
 
 #ifndef OPENSSL_NO_SRP
@@ -869,7 +1020,7 @@ static int ssl_check_srp_ext_ClientHello(SSL *s, int *al)
 #endif
 
 int dtls_raw_hello_verify_request(WPACKET *pkt, unsigned char *cookie,
-                                  unsigned char cookie_len)
+                                  size_t cookie_len)
 {
     /* Always use DTLS 1.0 version: see RFC 6347 */
     if (!WPACKET_put_bytes_u16(pkt, DTLS1_VERSION)
@@ -881,45 +1032,31 @@ int dtls_raw_hello_verify_request(WPACKET *pkt, unsigned char *cookie,
 
 int dtls_construct_hello_verify_request(SSL *s, WPACKET *pkt)
 {
-    size_t msglen;
-
+    unsigned int cookie_leni;
     if (s->ctx->app_gen_cookie_cb == NULL ||
         s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
-                                  &(s->d1->cookie_len)) == 0 ||
-        s->d1->cookie_len > 255) {
+                                  &cookie_leni) == 0 ||
+        cookie_leni > 255) {
         SSLerr(SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST,
                SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
         return 0;
     }
+    s->d1->cookie_len = cookie_leni;
 
-    if (!ssl_set_handshake_header(s, pkt,
-                                         DTLS1_MT_HELLO_VERIFY_REQUEST)
-            || !dtls_raw_hello_verify_request(pkt, s->d1->cookie,
-                                              s->d1->cookie_len)
-               /*
-                * We don't call close_construct_packet() because we don't want
-                * to buffer this message
-                */
-            || !WPACKET_close(pkt)
-            || !WPACKET_get_length(pkt, &msglen)
-            || !WPACKET_finish(pkt)) {
+    if (!dtls_raw_hello_verify_request(pkt, s->d1->cookie,
+                                              s->d1->cookie_len)) {
         SSLerr(SSL_F_DTLS_CONSTRUCT_HELLO_VERIFY_REQUEST, ERR_R_INTERNAL_ERROR);
         return 0;
     }
 
-    /* number of bytes to write */
-    s->d1->w_msg_hdr.msg_len = msglen - DTLS1_HM_HEADER_LENGTH;
-    s->d1->w_msg_hdr.frag_len = msglen - DTLS1_HM_HEADER_LENGTH;
-    s->init_num = (int)msglen;
-    s->init_off = 0;
-
     return 1;
 }
 
 MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
 {
     int i, al = SSL_AD_INTERNAL_ERROR;
-    unsigned int j, complen = 0;
+    unsigned int j;
+    size_t loop;
     unsigned long id;
     const SSL_CIPHER *c;
 #ifndef OPENSSL_NO_COMP
@@ -928,17 +1065,20 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
     STACK_OF(SSL_CIPHER) *ciphers = NULL;
     int protverr;
     /* |cookie| will only be initialized for DTLS. */
-    PACKET session_id, cipher_suites, compression, extensions, cookie;
-    int is_v2_record;
+    PACKET session_id, compression, extensions, cookie;
     static const unsigned char null_compression = 0;
+    CLIENTHELLO_MSG clienthello;
 
-    is_v2_record = RECORD_LAYER_is_sslv2_record(&s->rlayer);
-
+    /*
+     * First, parse the raw ClientHello data into the CLIENTHELLO_MSG structure.
+     */
+    memset(&clienthello, 0, sizeof(clienthello));
+    clienthello.isv2 = RECORD_LAYER_is_sslv2_record(&s->rlayer);
     PACKET_null_init(&cookie);
-    /* First lets get s->client_version set correctly */
-    if (is_v2_record) {
-        unsigned int version;
+
+    if (clienthello.isv2) {
         unsigned int mt;
+
         /*-
          * An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
          * header is sent directly on the wire, not wrapped as a TLS
@@ -964,73 +1104,25 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
             goto err;
         }
-
-        if (!PACKET_get_net_2(pkt, &version)) {
-            /* No protocol version supplied! */
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
-            goto err;
-        }
-        if (version == 0x0002) {
-            /* This is real SSLv2. We don't support it. */
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
-            goto err;
-        } else if ((version & 0xff00) == (SSL3_VERSION_MAJOR << 8)) {
-            /* SSLv3/TLS */
-            s->client_version = version;
-        } else {
-            /* No idea what protocol this is */
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
-            goto err;
-        }
-    } else {
-        /*
-         * use version from inside client hello, not from record header (may
-         * differ: see RFC 2246, Appendix E, second paragraph)
-         */
-        if (!PACKET_get_net_2(pkt, (unsigned int *)&s->client_version)) {
-            al = SSL_AD_DECODE_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
-            goto f_err;
-        }
     }
 
-    /*
-     * Do SSL/TLS version negotiation if applicable. For DTLS we just check
-     * versions are potentially compatible. Version negotiation comes later.
-     */
-    if (!SSL_IS_DTLS(s)) {
-        protverr = ssl_choose_server_version(s);
-    } else if (s->method->version != DTLS_ANY_VERSION &&
-               DTLS_VERSION_LT(s->client_version, s->version)) {
-        protverr = SSL_R_VERSION_TOO_LOW;
-    } else {
-        protverr = 0;
-    }
-
-    if (protverr) {
-        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, protverr);
-        if ((!s->enc_write_ctx && !s->write_hash)) {
-            /*
-             * similar to ssl3_get_record, send alert using remote version
-             * number
-             */
-            s->version = s->client_version;
-        }
-        al = SSL_AD_PROTOCOL_VERSION;
-        goto f_err;
+    if (!PACKET_get_net_2(pkt, &clienthello.legacy_version)) {
+        al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
+        goto err;
     }
 
     /* Parse the message and load client random. */
-    if (is_v2_record) {
+    if (clienthello.isv2) {
         /*
          * Handle an SSLv2 backwards compatible ClientHello
          * Note, this is only for SSLv3+ using the backward compatible format.
-         * Real SSLv2 is not supported, and is rejected above.
+         * Real SSLv2 is not supported, and is rejected below.
          */
-        unsigned int cipher_len, session_id_len, challenge_len;
+        unsigned int ciphersuite_len, session_id_len, challenge_len;
         PACKET challenge;
 
-        if (!PACKET_get_net_2(pkt, &cipher_len)
+        if (!PACKET_get_net_2(pkt, &ciphersuite_len)
             || !PACKET_get_net_2(pkt, &session_id_len)
             || !PACKET_get_net_2(pkt, &challenge_len)) {
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO,
@@ -1045,8 +1137,9 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             goto f_err;
         }
 
-        if (!PACKET_get_sub_packet(pkt, &cipher_suites, cipher_len)
-            || !PACKET_get_sub_packet(pkt, &session_id, session_id_len)
+        if (!PACKET_get_sub_packet(pkt, &clienthello.ciphersuites,
+                                   ciphersuite_len)
+            || !PACKET_copy_bytes(pkt, clienthello.session_id, session_id_len)
             || !PACKET_get_sub_packet(pkt, &challenge, challenge_len)
             /* No extensions. */
             || PACKET_remaining(pkt) != 0) {
@@ -1055,13 +1148,18 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             al = SSL_AD_DECODE_ERROR;
             goto f_err;
         }
+        clienthello.session_id_len = session_id_len;
 
-        /* Load the client random and compression list. */
-        challenge_len = challenge_len > SSL3_RANDOM_SIZE ? SSL3_RANDOM_SIZE :
-            challenge_len;
-        memset(s->s3->client_random, 0, SSL3_RANDOM_SIZE);
+        /* Load the client random and compression list. We use SSL3_RANDOM_SIZE
+         * here rather than sizeof(clienthello.random) because that is the limit
+         * for SSLv3 and it is fixed. It won't change even if
+         * sizeof(clienthello.random) does.
+         */
+        challenge_len = challenge_len > SSL3_RANDOM_SIZE
+                        ? SSL3_RANDOM_SIZE : challenge_len;
+        memset(clienthello.random, 0, SSL3_RANDOM_SIZE);
         if (!PACKET_copy_bytes(&challenge,
-                               s->s3->client_random + SSL3_RANDOM_SIZE -
+                               clienthello.random + SSL3_RANDOM_SIZE -
                                challenge_len, challenge_len)
             /* Advertise only null compression. */
             || !PACKET_buf_init(&compression, &null_compression, 1)) {
@@ -1070,17 +1168,14 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             goto f_err;
         }
 
-        PACKET_null_init(&extensions);
+        PACKET_null_init(&clienthello.extensions);
     } else {
         /* Regular ClientHello. */
-        if (!PACKET_copy_bytes(pkt, s->s3->client_random, SSL3_RANDOM_SIZE)
-            || !PACKET_get_length_prefixed_1(pkt, &session_id)) {
-            al = SSL_AD_DECODE_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
-            goto f_err;
-        }
-
-        if (PACKET_remaining(&session_id) > SSL_MAX_SSL_SESSION_ID_LENGTH) {
+        if (!PACKET_copy_bytes(pkt, clienthello.random, SSL3_RANDOM_SIZE)
+            || !PACKET_get_length_prefixed_1(pkt, &session_id)
+            || !PACKET_copy_all(&session_id, clienthello.session_id,
+                    SSL_MAX_SSL_SESSION_ID_LENGTH,
+                    &clienthello.session_id_len)) {
             al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
             goto f_err;
@@ -1092,34 +1187,114 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
                 SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
                 goto f_err;
             }
+            if (!PACKET_copy_all(&cookie, clienthello.dtls_cookie,
+                                 DTLS1_COOKIE_LENGTH,
+                                 &clienthello.dtls_cookie_len)) {
+                al = SSL_AD_DECODE_ERROR;
+                SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
+                goto f_err;
+            }
             /*
              * If we require cookies and this ClientHello doesn't contain one,
              * just return since we do not want to allocate any memory yet.
              * So check cookie length...
              */
             if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
-                if (PACKET_remaining(&cookie) == 0)
+                if (clienthello.dtls_cookie_len == 0)
                     return 1;
             }
         }
 
-        if (!PACKET_get_length_prefixed_2(pkt, &cipher_suites)
-            || !PACKET_get_length_prefixed_1(pkt, &compression)) {
+        if (!PACKET_get_length_prefixed_2(pkt, &clienthello.ciphersuites)) {
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
+            goto f_err;
+        }
+
+        if (!PACKET_get_length_prefixed_1(pkt, &compression)) {
             al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
             goto f_err;
         }
+
         /* Could be empty. */
-        extensions = *pkt;
+        if (PACKET_remaining(pkt) == 0) {
+            PACKET_null_init(&clienthello.extensions);
+        } else {
+            if (!PACKET_get_length_prefixed_2(pkt, &clienthello.extensions)) {
+                al = SSL_AD_DECODE_ERROR;
+                SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
+                goto f_err;
+            }
+        }
+    }
+
+    if (!PACKET_copy_all(&compression, clienthello.compressions,
+                         MAX_COMPRESSIONS_SIZE,
+                         &clienthello.compressions_len)) {
+        al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
+        goto f_err;
+    }
+
+    /* Preserve the raw extensions PACKET for later use */
+    extensions = clienthello.extensions;
+    if (!tls_collect_extensions(&extensions, &clienthello.pre_proc_exts,
+                                  &clienthello.num_extensions, &al)) {
+        /* SSLerr already been called */
+        goto f_err;
+    }
+
+    /* Finished parsing the ClientHello, now we can start processing it */
+
+    /* Set up the client_random */
+    memcpy(s->s3->client_random, clienthello.random, SSL3_RANDOM_SIZE);
+
+    /* Choose the version */
+
+    if (clienthello.isv2) {
+        if (clienthello.legacy_version == SSL2_VERSION
+                || (clienthello.legacy_version & 0xff00)
+                   != (SSL3_VERSION_MAJOR << 8)) {
+            /*
+             * This is real SSLv2 or something complete unknown. We don't
+             * support it.
+             */
+            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
+            goto err;
+        }
+        /* SSLv3/TLS */
+        s->client_version = clienthello.legacy_version;
+    }
+    /*
+     * Do SSL/TLS version negotiation if applicable. For DTLS we just check
+     * versions are potentially compatible. Version negotiation comes later.
+     */
+    if (!SSL_IS_DTLS(s)) {
+        protverr = ssl_choose_server_version(s, &clienthello);
+    } else if (s->method->version != DTLS_ANY_VERSION &&
+               DTLS_VERSION_LT((int)clienthello.legacy_version, s->version)) {
+        protverr = SSL_R_VERSION_TOO_LOW;
+    } else {
+        protverr = 0;
+    }
+
+    if (protverr) {
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, protverr);
+        if ((!s->enc_write_ctx && !s->write_hash)) {
+            /* like ssl3_get_record, send alert using remote version number */
+            s->version = s->client_version = clienthello.legacy_version;
+        }
+        al = SSL_AD_PROTOCOL_VERSION;
+        goto f_err;
     }
 
     if (SSL_IS_DTLS(s)) {
         /* Empty cookie was already handled above by returning early. */
         if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {
             if (s->ctx->app_verify_cookie_cb != NULL) {
-                if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookie),
-                                                 PACKET_remaining(&cookie)) ==
-                    0) {
+                if (s->ctx->app_verify_cookie_cb(s, clienthello.dtls_cookie,
+                        clienthello.dtls_cookie_len) == 0) {
                     al = SSL_AD_HANDSHAKE_FAILURE;
                     SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO,
                            SSL_R_COOKIE_MISMATCH);
@@ -1127,7 +1302,9 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
                     /* else cookie verification succeeded */
                 }
                 /* default verification */
-            } else if (!PACKET_equal(&cookie, s->d1->cookie, s->d1->cookie_len)) {
+            } else if (s->d1->cookie_len != clienthello.dtls_cookie_len
+                    || memcmp(clienthello.dtls_cookie, s->d1->cookie,
+                              s->d1->cookie_len) != 0) {
                 al = SSL_AD_HANDSHAKE_FAILURE;
                 SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_COOKIE_MISMATCH);
                 goto f_err;
@@ -1135,7 +1312,7 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             s->d1->cookie_verified = 1;
         }
         if (s->method->version == DTLS_ANY_VERSION) {
-            protverr = ssl_choose_server_version(s);
+            protverr = ssl_choose_server_version(s, &clienthello);
             if (protverr != 0) {
                 SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, protverr);
                 s->version = s->client_version;
@@ -1147,6 +1324,14 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
 
     s->hit = 0;
 
+    /* We need to do this before getting the session */
+    if (!tls_check_client_ems_support(s, &clienthello)) {
+        /* Only fails if the extension is malformed */
+        al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
+        goto f_err;
+    }
+
     /*
      * We don't allow resumption in a backwards compatible ClientHello.
      * TODO(openssl-team): in TLS1.1+, session_id MUST be empty.
@@ -1163,13 +1348,13 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
      * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
      * ignored.
      */
-    if (is_v2_record ||
+    if (clienthello.isv2 ||
         (s->new_session &&
          (s->options & SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
         if (!ssl_get_new_session(s, 1))
             goto err;
     } else {
-        i = ssl_get_prev_session(s, &extensions, &session_id);
+        i = ssl_get_prev_session(s, &clienthello);
         /*
          * Only resume if the session's version matches the negotiated
          * version.
@@ -1191,8 +1376,8 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
         }
     }
 
-    if (ssl_bytes_to_cipher_list(s, &cipher_suites, &(ciphers),
-                                 is_v2_record, &al) == NULL) {
+    if (ssl_bytes_to_cipher_list(s, &clienthello.ciphersuites, &ciphers,
+                                 clienthello.isv2, &al) == NULL) {
         goto f_err;
     }
 
@@ -1227,13 +1412,12 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
         }
     }
 
-    complen = PACKET_remaining(&compression);
-    for (j = 0; j < complen; j++) {
-        if (PACKET_data(&compression)[j] == 0)
+    for (loop = 0; loop < clienthello.compressions_len; loop++) {
+        if (clienthello.compressions[loop] == 0)
             break;
     }
 
-    if (j >= complen) {
+    if (loop >= clienthello.compressions_len) {
         /* no compress */
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_NO_COMPRESSION_SPECIFIED);
@@ -1241,11 +1425,18 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
     }
 
     /* TLS extensions */
-    if (s->version >= SSL3_VERSION) {
-        if (!ssl_parse_clienthello_tlsext(s, &extensions)) {
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_PARSE_TLSEXT);
-            goto err;
-        }
+    if (!ssl_parse_clienthello_tlsext(s, &clienthello)) {
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_PARSE_TLSEXT);
+        goto err;
+    }
+
+    /* Check we've got a key_share for TLSv1.3 */
+    if (SSL_IS_TLS13(s) && s->s3->peer_tmp == NULL && !s->hit) {
+        /* No suitable share */
+        /* TODO(TLS1.3): Send a HelloRetryRequest */
+        al = SSL_AD_HANDSHAKE_FAILURE;
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_NO_SUITABLE_KEY_SHARE);
+        goto f_err;
     }
 
     /*
@@ -1264,12 +1455,19 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
 
     if (!s->hit && s->version >= TLS1_VERSION && s->tls_session_secret_cb) {
         const SSL_CIPHER *pref_cipher = NULL;
+        /*
+         * s->session->master_key_length is a size_t, but this is an int for
+         * backwards compat reasons
+         */
+        int master_key_length;
 
-        s->session->master_key_length = sizeof(s->session->master_key);
+        master_key_length = sizeof(s->session->master_key);
         if (s->tls_session_secret_cb(s, s->session->master_key,
-                                     &s->session->master_key_length, ciphers,
+                                     &master_key_length, ciphers,
                                      &pref_cipher,
-                                     s->tls_session_secret_cb_arg)) {
+                                     s->tls_session_secret_cb_arg)
+                && master_key_length > 0) {
+            s->session->master_key_length = master_key_length;
             s->hit = 1;
             s->session->ciphers = ciphers;
             s->session->verify_result = X509_V_OK;
@@ -1329,11 +1527,11 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             goto f_err;
         }
         /* Look for resumed method in compression list */
-        for (k = 0; k < complen; k++) {
-            if (PACKET_data(&compression)[k] == comp_id)
+        for (k = 0; k < clienthello.compressions_len; k++) {
+            if (clienthello.compressions[k] == comp_id)
                 break;
         }
-        if (k >= complen) {
+        if (k >= clienthello.compressions_len) {
             al = SSL_AD_ILLEGAL_PARAMETER;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO,
                    SSL_R_REQUIRED_COMPRESSION_ALGORITHM_MISSING);
@@ -1350,8 +1548,8 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
         for (m = 0; m < nn; m++) {
             comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
             v = comp->id;
-            for (o = 0; o < complen; o++) {
-                if (v == PACKET_data(&compression)[o]) {
+            for (o = 0; o < clienthello.compressions_len; o++) {
+                if (v == clienthello.compressions[o]) {
                     done = 1;
                     break;
                 }
@@ -1400,6 +1598,7 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
     }
 
     sk_SSL_CIPHER_free(ciphers);
+    OPENSSL_free(clienthello.pre_proc_exts);
     return MSG_PROCESS_CONTINUE_PROCESSING;
  f_err:
     ssl3_send_alert(s, SSL3_AL_FATAL, al);
@@ -1407,8 +1606,9 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
     ossl_statem_set_error(s);
 
     sk_SSL_CIPHER_free(ciphers);
-    return MSG_PROCESS_ERROR;
+    OPENSSL_free(clienthello.pre_proc_exts);
 
+    return MSG_PROCESS_ERROR;
 }
 
 WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
@@ -1502,6 +1702,9 @@ WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
             if (al != TLS1_AD_UNKNOWN_PSK_IDENTITY)
                 SSLerr(SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
                        SSL_R_CLIENTHELLO_TLSEXT);
+            else
+                SSLerr(SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
+                       SSL_R_PSK_IDENTITY_NOT_FOUND);
             goto f_err;
         }
     }
@@ -1517,10 +1720,13 @@ WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
 
 int tls_construct_server_hello(SSL *s, WPACKET *pkt)
 {
-    int sl, compm, al = SSL_AD_INTERNAL_ERROR;
-    size_t len;
+    int compm, al = SSL_AD_INTERNAL_ERROR;
+    size_t sl, len;
+    int version;
 
-    if (!WPACKET_put_bytes_u16(pkt, s->version)
+    /* TODO(TLS1.3): Remove the DRAFT conditional before release */
+    version = SSL_IS_TLS13(s) ? TLS1_3_VERSION_DRAFT : s->version;
+    if (!WPACKET_put_bytes_u16(pkt, version)
                /*
                 * Random stuff. Filling of the server_random takes place in
                 * tls_process_client_hello()
@@ -1552,7 +1758,7 @@ int tls_construct_server_hello(SSL *s, WPACKET *pkt)
         s->session->session_id_length = 0;
 
     sl = s->session->session_id_length;
-    if (sl > (int)sizeof(s->session->session_id)) {
+    if (sl > sizeof(s->session->session_id)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
         goto err;
     }
@@ -1600,7 +1806,7 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
 #endif
 #ifndef OPENSSL_NO_EC
     unsigned char *encodedPoint = NULL;
-    int encodedlen = 0;
+    size_t encodedlen = 0;
     int curve_id = 0;
 #endif
     EVP_PKEY *pkey;
@@ -1706,7 +1912,7 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
         }
 
         /* Get NID of appropriate shared curve */
-        nid = tls1_shared_curve(s, -2);
+        nid = tls1_shared_group(s, -2);
         curve_id = tls1_ec_nid2curve_id(nid);
         if (curve_id == 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_SERVER_KEY_EXCHANGE,
@@ -1933,7 +2139,7 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
 
 int tls_construct_certificate_request(SSL *s, WPACKET *pkt)
 {
-    int i, nl;
+    int i;
     STACK_OF(X509_NAME) *sk = NULL;
 
     /* get the list of acceptable cert types */
@@ -1946,7 +2152,7 @@ int tls_construct_certificate_request(SSL *s, WPACKET *pkt)
 
     if (SSL_USE_SIGALGS(s)) {
         const unsigned char *psigs;
-        nl = tls12_get_psigalgs(s, &psigs);
+        size_t nl = tls12_get_psigalgs(s, &psigs);
         if (!WPACKET_start_sub_packet_u16(pkt)
                 || !tls12_copy_sigalgs(s, pkt, psigs, nl)
                 || !WPACKET_close(pkt)) {
@@ -2127,9 +2333,10 @@ static int tls_process_cke_rsa(SSL *s, PACKET *pkt, int *al)
      * Decrypt with no padding. PKCS#1 padding will be removed as part of
      * the timing-sensitive code below.
      */
-    decrypt_len = RSA_private_decrypt(PACKET_remaining(&enc_premaster),
-                                      PACKET_data(&enc_premaster),
-                                      rsa_decrypt, rsa, RSA_NO_PADDING);
+     /* TODO(size_t): Convert this function */
+    decrypt_len = (int)RSA_private_decrypt((int)PACKET_remaining(&enc_premaster),
+                                           PACKET_data(&enc_premaster),
+                                           rsa_decrypt, rsa, RSA_NO_PADDING);
     if (decrypt_len < 0)
         goto err;
 
@@ -2276,7 +2483,7 @@ static int tls_process_cke_dhe(SSL *s, PACKET *pkt, int *al)
         goto err;
     }
 
-    if (ssl_derive(s, skey, ckey) == 0) {
+    if (ssl_derive(s, skey, ckey, 1) == 0) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CKE_DHE, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -2336,7 +2543,7 @@ static int tls_process_cke_ecdhe(SSL *s, PACKET *pkt, int *al)
         }
     }
 
-    if (ssl_derive(s, skey, ckey) == 0) {
+    if (ssl_derive(s, skey, ckey, 1) == 0) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CKE_ECDHE, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -2410,7 +2617,7 @@ static int tls_process_cke_gost(SSL *s, PACKET *pkt, int *al)
     unsigned long alg_a;
     int Ttag, Tclass;
     long Tlen;
-    long sess_key_len;
+    size_t sess_key_len;
     const unsigned char *data;
     int ret = 0;
 
@@ -2460,8 +2667,9 @@ static int tls_process_cke_gost(SSL *s, PACKET *pkt, int *al)
         SSLerr(SSL_F_TLS_PROCESS_CKE_GOST, ERR_R_INTERNAL_ERROR);
         goto err;
     }
+    /* TODO(size_t): Convert this function */
     if (ASN1_get_object((const unsigned char **)&data, &Tlen, &Ttag,
-                        &Tclass, sess_key_len) != V_ASN1_CONSTRUCTED
+                        &Tclass, (long)sess_key_len) != V_ASN1_CONSTRUCTED
         || Ttag != V_ASN1_SEQUENCE || Tclass != V_ASN1_UNIVERSAL) {
         *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CKE_GOST, SSL_R_DECRYPTION_FAILED);
@@ -2735,6 +2943,7 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
         al = SSL_AD_INTERNAL_ERROR;
         goto f_err;
     }
+
 #ifdef SSL_DEBUG
     fprintf(stderr, "Using client verify alg %s\n", EVP_MD_name(md));
 #endif
@@ -2763,7 +2972,7 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
 
     if (s->version == SSL3_VERSION
         && !EVP_MD_CTX_ctrl(mctx, EVP_CTRL_SSL3_MASTER_SECRET,
-                            s->session->master_key_length,
+                            (int)s->session->master_key_length,
                             s->session->master_key)) {
         SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_EVP_LIB);
         al = SSL_AD_INTERNAL_ERROR;
@@ -2890,6 +3099,17 @@ MSG_PROCESS_RETURN tls_process_client_certificate(SSL *s, PACKET *pkt)
 
     sk_X509_pop_free(s->session->peer_chain, X509_free);
     s->session->peer_chain = sk;
+
+    /*
+     * Freeze the handshake buffer. For <TLS1.3 we do this after the CKE
+     * message
+     */
+    if (SSL_IS_TLS13(s) && !ssl3_digest_cached_records(s, 1)) {
+        al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_CLIENT_CERTIFICATE, ERR_R_INTERNAL_ERROR);
+        goto f_err;
+    }
+
     /*
      * Inconsistency alert: cert_chain does *not* include the peer's own
      * certificate, while we do include it in statem_clnt.c
@@ -3002,8 +3222,7 @@ int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt)
 
             /* Put timeout and length */
             if (!WPACKET_put_bytes_u32(pkt, 0)
-                    || !WPACKET_put_bytes_u16(pkt, 0)
-                    || !ssl_close_construct_packet(s, pkt)) {
+                    || !WPACKET_put_bytes_u16(pkt, 0)) {
                 SSLerr(SSL_F_TLS_CONSTRUCT_NEW_SESSION_TICKET,
                        ERR_R_INTERNAL_ERROR);
                 goto err;