Add -Wswitch-enum
[openssl.git] / ssl / statem / statem_clnt.c
index 6d937a4..67f4ac4 100644 (file)
@@ -63,8 +63,7 @@ static ossl_inline int cert_req_allowed(SSL *s);
 static int key_exchange_expected(SSL *s);
 static int ca_dn_cmp(const X509_NAME *const *a, const X509_NAME *const *b);
 static int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk,
-                                    unsigned char *p);
-
+                                    WPACKET *pkt);
 
 /*
  * Is a CertificateRequest message allowed at the moment or not?
@@ -77,8 +76,8 @@ static ossl_inline int cert_req_allowed(SSL *s)
 {
     /* TLS does not like anon-DH with client cert */
     if ((s->version > SSL3_VERSION
-                && (s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL))
-            || (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aSRP | SSL_aPSK)))
+         && (s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL))
+        || (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aSRP | SSL_aPSK)))
         return 0;
 
     return 1;
@@ -122,7 +121,10 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
     OSSL_STATEM *st = &s->statem;
     int ske_expected;
 
-    switch(st->hand_state) {
+    switch (st->hand_state) {
+    default:
+        break;
+
     case TLS_ST_CW_CLNT_HELLO:
         if (mt == SSL3_MT_SERVER_HELLO) {
             st->hand_state = TLS_ST_CR_SRVR_HELLO;
@@ -153,9 +155,9 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
                 st->hand_state = DTLS_ST_CR_HELLO_VERIFY_REQUEST;
                 return 1;
             } else if (s->version >= TLS1_VERSION
-                    && s->tls_session_secret_cb != NULL
-                    && s->session->tlsext_tick != NULL
-                    && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
+                       && s->tls_session_secret_cb != NULL
+                       && s->session->tlsext_tick != NULL
+                       && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
                 /*
                  * Normally, we can tell if the server is resuming the session
                  * from the session ID. EAP-FAST (RFC 4851), however, relies on
@@ -166,7 +168,7 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
                 st->hand_state = TLS_ST_CR_CHANGE;
                 return 1;
             } else if (!(s->s3->tmp.new_cipher->algorithm_auth
-                        & (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
+                         & (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
                 if (mt == SSL3_MT_CERTIFICATE) {
                     st->hand_state = TLS_ST_CR_CERT;
                     return 1;
@@ -175,19 +177,19 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
                 ske_expected = key_exchange_expected(s);
                 /* SKE is optional for some PSK ciphersuites */
                 if (ske_expected
-                        || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
-                            && mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
+                    || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
+                        && mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
                     if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
                         st->hand_state = TLS_ST_CR_KEY_EXCH;
                         return 1;
                     }
                 } else if (mt == SSL3_MT_CERTIFICATE_REQUEST
-                            && cert_req_allowed(s)) {
-                        st->hand_state = TLS_ST_CR_CERT_REQ;
-                        return 1;
+                           && cert_req_allowed(s)) {
+                    st->hand_state = TLS_ST_CR_CERT_REQ;
+                    return 1;
                 } else if (mt == SSL3_MT_SERVER_DONE) {
-                        st->hand_state = TLS_ST_CR_SRVR_DONE;
-                        return 1;
+                    st->hand_state = TLS_ST_CR_SRVR_DONE;
+                    return 1;
                 }
             }
         }
@@ -207,9 +209,8 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
     case TLS_ST_CR_CERT_STATUS:
         ske_expected = key_exchange_expected(s);
         /* SKE is optional for some PSK ciphersuites */
-        if (ske_expected
-                || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
-                    && mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
+        if (ske_expected || ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)
+                             && mt == SSL3_MT_SERVER_KEY_EXCHANGE)) {
             if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) {
                 st->hand_state = TLS_ST_CR_KEY_EXCH;
                 return 1;
@@ -260,9 +261,6 @@ int ossl_statem_client_read_transition(SSL *s, int mt)
             return 1;
         }
         break;
-
-    default:
-        break;
     }
 
  err:
@@ -280,99 +278,99 @@ WRITE_TRAN ossl_statem_client_write_transition(SSL *s)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
-        case TLS_ST_OK:
-            /* Renegotiation - fall through */
-        case TLS_ST_BEFORE:
-            st->hand_state = TLS_ST_CW_CLNT_HELLO;
-            return WRITE_TRAN_CONTINUE;
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return WRITE_TRAN_ERROR;
 
-        case TLS_ST_CW_CLNT_HELLO:
-            /*
-             * No transition at the end of writing because we don't know what
-             * we will be sent
-             */
-            return WRITE_TRAN_FINISHED;
+    case TLS_ST_OK:
+        /* Renegotiation - fall through */
+    case TLS_ST_BEFORE:
+        st->hand_state = TLS_ST_CW_CLNT_HELLO;
+        return WRITE_TRAN_CONTINUE;
 
-        case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
-            st->hand_state = TLS_ST_CW_CLNT_HELLO;
-            return WRITE_TRAN_CONTINUE;
+    case TLS_ST_CW_CLNT_HELLO:
+        /*
+         * No transition at the end of writing because we don't know what
+         * we will be sent
+         */
+        return WRITE_TRAN_FINISHED;
 
-        case TLS_ST_CR_SRVR_DONE:
-            if (s->s3->tmp.cert_req)
-                st->hand_state = TLS_ST_CW_CERT;
-            else
-                st->hand_state = TLS_ST_CW_KEY_EXCH;
-            return WRITE_TRAN_CONTINUE;
+    case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
+        st->hand_state = TLS_ST_CW_CLNT_HELLO;
+        return WRITE_TRAN_CONTINUE;
 
-        case TLS_ST_CW_CERT:
+    case TLS_ST_CR_SRVR_DONE:
+        if (s->s3->tmp.cert_req)
+            st->hand_state = TLS_ST_CW_CERT;
+        else
             st->hand_state = TLS_ST_CW_KEY_EXCH;
-            return WRITE_TRAN_CONTINUE;
+        return WRITE_TRAN_CONTINUE;
 
-        case TLS_ST_CW_KEY_EXCH:
-            /*
-             * For TLS, cert_req is set to 2, so a cert chain of nothing is
-             * sent, but no verify packet is sent
-             */
-            /*
-             * XXX: For now, we do not support client authentication in ECDH
-             * cipher suites with ECDH (rather than ECDSA) certificates. We
-             * need to skip the certificate verify message when client's
-             * ECDH public key is sent inside the client certificate.
-             */
-            if (s->s3->tmp.cert_req == 1) {
-                st->hand_state = TLS_ST_CW_CERT_VRFY;
-            } else {
-                st->hand_state = TLS_ST_CW_CHANGE;
-            }
-            if (s->s3->flags & TLS1_FLAGS_SKIP_CERT_VERIFY) {
-                st->hand_state = TLS_ST_CW_CHANGE;
-            }
-            return WRITE_TRAN_CONTINUE;
+    case TLS_ST_CW_CERT:
+        st->hand_state = TLS_ST_CW_KEY_EXCH;
+        return WRITE_TRAN_CONTINUE;
 
-        case TLS_ST_CW_CERT_VRFY:
+    case TLS_ST_CW_KEY_EXCH:
+        /*
+         * For TLS, cert_req is set to 2, so a cert chain of nothing is
+         * sent, but no verify packet is sent
+         */
+        /*
+         * XXX: For now, we do not support client authentication in ECDH
+         * cipher suites with ECDH (rather than ECDSA) certificates. We
+         * need to skip the certificate verify message when client's
+         * ECDH public key is sent inside the client certificate.
+         */
+        if (s->s3->tmp.cert_req == 1) {
+            st->hand_state = TLS_ST_CW_CERT_VRFY;
+        } else {
             st->hand_state = TLS_ST_CW_CHANGE;
-            return WRITE_TRAN_CONTINUE;
+        }
+        if (s->s3->flags & TLS1_FLAGS_SKIP_CERT_VERIFY) {
+            st->hand_state = TLS_ST_CW_CHANGE;
+        }
+        return WRITE_TRAN_CONTINUE;
 
-        case TLS_ST_CW_CHANGE:
+    case TLS_ST_CW_CERT_VRFY:
+        st->hand_state = TLS_ST_CW_CHANGE;
+        return WRITE_TRAN_CONTINUE;
+
+    case TLS_ST_CW_CHANGE:
 #if defined(OPENSSL_NO_NEXTPROTONEG)
-            st->hand_state = TLS_ST_CW_FINISHED;
+        st->hand_state = TLS_ST_CW_FINISHED;
 #else
-            if (!SSL_IS_DTLS(s) && s->s3->next_proto_neg_seen)
-                st->hand_state = TLS_ST_CW_NEXT_PROTO;
-            else
-                st->hand_state = TLS_ST_CW_FINISHED;
+        if (!SSL_IS_DTLS(s) && s->s3->next_proto_neg_seen)
+            st->hand_state = TLS_ST_CW_NEXT_PROTO;
+        else
+            st->hand_state = TLS_ST_CW_FINISHED;
 #endif
-            return WRITE_TRAN_CONTINUE;
+        return WRITE_TRAN_CONTINUE;
 
 #if !defined(OPENSSL_NO_NEXTPROTONEG)
-        case TLS_ST_CW_NEXT_PROTO:
-            st->hand_state = TLS_ST_CW_FINISHED;
-            return WRITE_TRAN_CONTINUE;
+    case TLS_ST_CW_NEXT_PROTO:
+        st->hand_state = TLS_ST_CW_FINISHED;
+        return WRITE_TRAN_CONTINUE;
 #endif
 
-        case TLS_ST_CW_FINISHED:
-            if (s->hit) {
-                st->hand_state = TLS_ST_OK;
-                ossl_statem_set_in_init(s, 0);
-                return WRITE_TRAN_CONTINUE;
-            } else {
-                return WRITE_TRAN_FINISHED;
-            }
-
-        case TLS_ST_CR_FINISHED:
-            if (s->hit) {
-                st->hand_state = TLS_ST_CW_CHANGE;
-                return WRITE_TRAN_CONTINUE;
-            } else {
-                st->hand_state = TLS_ST_OK;
-                ossl_statem_set_in_init(s, 0);
-                return WRITE_TRAN_CONTINUE;
-            }
+    case TLS_ST_CW_FINISHED:
+        if (s->hit) {
+            st->hand_state = TLS_ST_OK;
+            ossl_statem_set_in_init(s, 0);
+            return WRITE_TRAN_CONTINUE;
+        } else {
+            return WRITE_TRAN_FINISHED;
+        }
 
-        default:
-            /* Shouldn't happen */
-            return WRITE_TRAN_ERROR;
+    case TLS_ST_CR_FINISHED:
+        if (s->hit) {
+            st->hand_state = TLS_ST_CW_CHANGE;
+            return WRITE_TRAN_CONTINUE;
+        } else {
+            st->hand_state = TLS_ST_OK;
+            ossl_statem_set_in_init(s, 0);
+            return WRITE_TRAN_CONTINUE;
+        }
     }
 }
 
@@ -384,7 +382,11 @@ WORK_STATE ossl_statem_client_pre_work(SSL *s, WORK_STATE wst)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
+    switch (st->hand_state) {
+    default:
+        /* No pre work to be done */
+        break;
+
     case TLS_ST_CW_CLNT_HELLO:
         s->shutdown = 0;
         if (SSL_IS_DTLS(s)) {
@@ -410,14 +412,10 @@ WORK_STATE ossl_statem_client_pre_work(SSL *s, WORK_STATE wst)
                 return dtls_wait_for_dry(s);
 #endif
         }
-        return WORK_FINISHED_CONTINUE;
+        break;
 
     case TLS_ST_OK:
         return tls_finish_handshake(s, wst);
-
-    default:
-        /* No pre work to be done */
-        break;
     }
 
     return WORK_FINISHED_CONTINUE;
@@ -433,7 +431,11 @@ WORK_STATE ossl_statem_client_post_work(SSL *s, WORK_STATE wst)
 
     s->init_num = 0;
 
-    switch(st->hand_state) {
+    switch (st->hand_state) {
+    default:
+        /* No post work to be done */
+        break;
+
     case TLS_ST_CW_CLNT_HELLO:
         if (wst == WORK_MORE_A && statem_flush(s) != 1)
             return WORK_MORE_A;
@@ -496,10 +498,6 @@ WORK_STATE ossl_statem_client_post_work(SSL *s, WORK_STATE wst)
         if (statem_flush(s) != 1)
             return WORK_MORE_B;
         break;
-
-    default:
-        /* No post work to be done */
-        break;
     }
 
     return WORK_FINISHED_CONTINUE;
@@ -516,7 +514,11 @@ int ossl_statem_client_construct_message(SSL *s)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return 0;
+
     case TLS_ST_CW_CLNT_HELLO:
         return tls_construct_client_hello(s);
 
@@ -545,13 +547,7 @@ int ossl_statem_client_construct_message(SSL *s)
                                       ssl3_enc->client_finished_label,
                                       s->method->
                                       ssl3_enc->client_finished_label_len);
-
-    default:
-        /* Shouldn't happen */
-        break;
     }
-
-    return 0;
 }
 
 /*
@@ -562,47 +558,48 @@ unsigned long ossl_statem_client_max_message_size(SSL *s)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
-        case TLS_ST_CR_SRVR_HELLO:
-            return SERVER_HELLO_MAX_LENGTH;
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return 0;
 
-        case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
-            return HELLO_VERIFY_REQUEST_MAX_LENGTH;
+    case TLS_ST_CR_SRVR_HELLO:
+        return SERVER_HELLO_MAX_LENGTH;
 
-        case TLS_ST_CR_CERT:
-            return s->max_cert_list;
+    case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
+        return HELLO_VERIFY_REQUEST_MAX_LENGTH;
 
-        case TLS_ST_CR_CERT_STATUS:
-            return SSL3_RT_MAX_PLAIN_LENGTH;
+    case TLS_ST_CR_CERT:
+        return s->max_cert_list;
 
-        case TLS_ST_CR_KEY_EXCH:
-            return SERVER_KEY_EXCH_MAX_LENGTH;
+    case TLS_ST_CR_CERT_STATUS:
+        return SSL3_RT_MAX_PLAIN_LENGTH;
 
-        case TLS_ST_CR_CERT_REQ:
-            /* Set to s->max_cert_list for compatibility with previous releases.
-             * In practice these messages can get quite long if servers are
-             * configured to provide a long list of acceptable CAs
-             */
-            return s->max_cert_list;
+    case TLS_ST_CR_KEY_EXCH:
+        return SERVER_KEY_EXCH_MAX_LENGTH;
 
-        case TLS_ST_CR_SRVR_DONE:
-            return SERVER_HELLO_DONE_MAX_LENGTH;
+    case TLS_ST_CR_CERT_REQ:
+        /*
+         * Set to s->max_cert_list for compatibility with previous releases. In
+         * practice these messages can get quite long if servers are configured
+         * to provide a long list of acceptable CAs
+         */
+        return s->max_cert_list;
 
-        case TLS_ST_CR_CHANGE:
-            return CCS_MAX_LENGTH;
+    case TLS_ST_CR_SRVR_DONE:
+        return SERVER_HELLO_DONE_MAX_LENGTH;
 
-        case TLS_ST_CR_SESSION_TICKET:
-            return SSL3_RT_MAX_PLAIN_LENGTH;
+    case TLS_ST_CR_CHANGE:
+        if (s->version == DTLS1_BAD_VER)
+            return 3;
+        return CCS_MAX_LENGTH;
 
-        case TLS_ST_CR_FINISHED:
-            return FINISHED_MAX_LENGTH;
+    case TLS_ST_CR_SESSION_TICKET:
+        return SSL3_RT_MAX_PLAIN_LENGTH;
 
-        default:
-            /* Shouldn't happen */
-            break;
+    case TLS_ST_CR_FINISHED:
+        return FINISHED_MAX_LENGTH;
     }
-
-    return 0;
 }
 
 /*
@@ -612,43 +609,41 @@ MSG_PROCESS_RETURN ossl_statem_client_process_message(SSL *s, PACKET *pkt)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
-        case TLS_ST_CR_SRVR_HELLO:
-            return tls_process_server_hello(s, pkt);
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return MSG_PROCESS_ERROR;
 
-        case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
-            return dtls_process_hello_verify(s, pkt);
+    case TLS_ST_CR_SRVR_HELLO:
+        return tls_process_server_hello(s, pkt);
 
-        case TLS_ST_CR_CERT:
-            return tls_process_server_certificate(s, pkt);
+    case DTLS_ST_CR_HELLO_VERIFY_REQUEST:
+        return dtls_process_hello_verify(s, pkt);
 
-        case TLS_ST_CR_CERT_STATUS:
-            return tls_process_cert_status(s, pkt);
+    case TLS_ST_CR_CERT:
+        return tls_process_server_certificate(s, pkt);
 
-        case TLS_ST_CR_KEY_EXCH:
-            return tls_process_key_exchange(s, pkt);
+    case TLS_ST_CR_CERT_STATUS:
+        return tls_process_cert_status(s, pkt);
 
-        case TLS_ST_CR_CERT_REQ:
-            return tls_process_certificate_request(s, pkt);
+    case TLS_ST_CR_KEY_EXCH:
+        return tls_process_key_exchange(s, pkt);
 
-        case TLS_ST_CR_SRVR_DONE:
-            return tls_process_server_done(s, pkt);
+    case TLS_ST_CR_CERT_REQ:
+        return tls_process_certificate_request(s, pkt);
 
-        case TLS_ST_CR_CHANGE:
-            return tls_process_change_cipher_spec(s, pkt);
+    case TLS_ST_CR_SRVR_DONE:
+        return tls_process_server_done(s, pkt);
 
-        case TLS_ST_CR_SESSION_TICKET:
-            return tls_process_new_session_ticket(s, pkt);
+    case TLS_ST_CR_CHANGE:
+        return tls_process_change_cipher_spec(s, pkt);
 
-        case TLS_ST_CR_FINISHED:
-            return tls_process_finished(s, pkt);
+    case TLS_ST_CR_SESSION_TICKET:
+        return tls_process_new_session_ticket(s, pkt);
 
-        default:
-            /* Shouldn't happen */
-            break;
+    case TLS_ST_CR_FINISHED:
+        return tls_process_finished(s, pkt);
     }
-
-    return MSG_PROCESS_ERROR;
 }
 
 /*
@@ -659,7 +654,11 @@ WORK_STATE ossl_statem_client_post_process_message(SSL *s, WORK_STATE wst)
 {
     OSSL_STATEM *st = &s->statem;
 
-    switch(st->hand_state) {
+    switch (st->hand_state) {
+    default:
+        /* Shouldn't happen */
+        return WORK_ERROR;
+
     case TLS_ST_CR_CERT_REQ:
         return tls_prepare_client_certificate(s, wst);
 
@@ -677,30 +676,27 @@ WORK_STATE ossl_statem_client_post_process_message(SSL *s, WORK_STATE wst)
         ossl_statem_set_sctp_read_sock(s, 0);
         return WORK_FINISHED_STOP;
 #endif
-
-    default:
-        break;
     }
-
-    /* Shouldn't happen */
-    return WORK_ERROR;
 }
 
 int tls_construct_client_hello(SSL *s)
 {
-    unsigned char *buf;
-    unsigned char *p, *d;
+    unsigned char *p;
     int i;
     int protverr;
-    unsigned long l;
-    int al = 0;
+    int al = SSL_AD_HANDSHAKE_FAILURE;
 #ifndef OPENSSL_NO_COMP
-    int j;
     SSL_COMP *comp;
 #endif
     SSL_SESSION *sess = s->session;
+    WPACKET pkt;
 
-    buf = (unsigned char *)s->init_buf->data;
+    if (!WPACKET_init(&pkt, s->init_buf)
+            || !WPACKET_set_max_size(&pkt, SSL3_RT_MAX_PLAIN_LENGTH)) {
+        /* Should not happen */
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     /* Work out what SSL/TLS/DTLS version to use */
     protverr = ssl_set_client_hello_version(s);
@@ -709,8 +705,7 @@ int tls_construct_client_hello(SSL *s)
         goto err;
     }
 
-    if ((sess == NULL) ||
-        !ssl_version_supported(s, sess->ssl_version) ||
+    if ((sess == NULL) || !ssl_version_supported(s, sess->ssl_version) ||
         /*
          * In the case of EAP-FAST, we can have a pre-shared
          * "ticket" without a session ID.
@@ -740,12 +735,14 @@ int tls_construct_client_hello(SSL *s)
     } else
         i = 1;
 
-    if (i && ssl_fill_hello_random(s, 0, p,
-                                   sizeof(s->s3->client_random)) <= 0)
+    if (i && ssl_fill_hello_random(s, 0, p, sizeof(s->s3->client_random)) <= 0)
         goto err;
 
-    /* Do the message type and length last */
-    d = p = ssl_handshake_start(s);
+    if (!ssl_set_handshake_header2(s, &pkt, SSL3_MT_CLIENT_HELLO)) {
+        ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     /*-
      * version indicates the negotiated version: for example from
@@ -777,90 +774,90 @@ int tls_construct_client_hello(SSL *s)
      * client_version in client hello and not resetting it to
      * the negotiated version.
      */
-    *(p++) = s->client_version >> 8;
-    *(p++) = s->client_version & 0xff;
-
-    /* Random stuff */
-    memcpy(p, s->s3->client_random, SSL3_RANDOM_SIZE);
-    p += SSL3_RANDOM_SIZE;
+    if (!WPACKET_put_bytes_u16(&pkt, s->client_version)
+            || !WPACKET_memcpy(&pkt, s->s3->client_random, SSL3_RANDOM_SIZE)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     /* Session ID */
     if (s->new_session)
         i = 0;
     else
         i = s->session->session_id_length;
-    *(p++) = i;
-    if (i != 0) {
-        if (i > (int)sizeof(s->session->session_id)) {
-            SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
-            goto err;
-        }
-        memcpy(p, s->session->session_id, i);
-        p += i;
+    if (i > (int)sizeof(s->session->session_id)
+            || !WPACKET_start_sub_packet_u8(&pkt)
+            || (i != 0 && !WPACKET_memcpy(&pkt, s->session->session_id, i))
+            || !WPACKET_close(&pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
 
     /* cookie stuff for DTLS */
     if (SSL_IS_DTLS(s)) {
-        if (s->d1->cookie_len > sizeof(s->d1->cookie)) {
+        if (s->d1->cookie_len > sizeof(s->d1->cookie)
+                || !WPACKET_sub_memcpy_u8(&pkt, s->d1->cookie,
+                                          s->d1->cookie_len)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
             goto err;
         }
-        *(p++) = s->d1->cookie_len;
-        memcpy(p, s->d1->cookie, s->d1->cookie_len);
-        p += s->d1->cookie_len;
     }
 
     /* Ciphers supported */
-    i = ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &(p[2]));
-    if (i == 0) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, SSL_R_NO_CIPHERS_AVAILABLE);
+    if (!WPACKET_start_sub_packet_u16(&pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+    /* ssl_cipher_list_to_bytes() raises SSLerr if appropriate */
+    if (!ssl_cipher_list_to_bytes(s, SSL_get_ciphers(s), &pkt))
+        goto err;
+    if (!WPACKET_close(&pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
         goto err;
     }
-#ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
-    /*
-     * Some servers hang if client hello > 256 bytes as hack workaround
-     * chop number of supported ciphers to keep it well below this if we
-     * use TLS v1.2
-     */
-    if (TLS1_get_version(s) >= TLS1_2_VERSION
-        && i > OPENSSL_MAX_TLS1_2_CIPHER_LENGTH)
-        i = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
-#endif
-    s2n(i, p);
-    p += i;
 
     /* COMPRESSION */
-#ifdef OPENSSL_NO_COMP
-    *(p++) = 1;
-#else
-
-    if (!ssl_allow_compression(s) || !s->ctx->comp_methods)
-        j = 0;
-    else
-        j = sk_SSL_COMP_num(s->ctx->comp_methods);
-    *(p++) = 1 + j;
-    for (i = 0; i < j; i++) {
-        comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);
-        *(p++) = comp->id;
+    if (!WPACKET_start_sub_packet_u8(&pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+#ifndef OPENSSL_NO_COMP
+    if (ssl_allow_compression(s) && s->ctx->comp_methods) {
+        int compnum = sk_SSL_COMP_num(s->ctx->comp_methods);
+        for (i = 0; i < compnum; i++) {
+            comp = sk_SSL_COMP_value(s->ctx->comp_methods, i);
+            if (!WPACKET_put_bytes_u8(&pkt, comp->id)) {
+                SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+                goto err;
+            }
+        }
     }
 #endif
-    *(p++) = 0;             /* Add the NULL method */
+    /* Add the NULL method */
+    if (!WPACKET_put_bytes_u8(&pkt, 0) || !WPACKET_close(&pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     /* TLS extensions */
     if (ssl_prepare_clienthello_tlsext(s) <= 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
         goto err;
     }
-    if ((p =
-         ssl_add_clienthello_tlsext(s, p, buf + SSL3_RT_MAX_PLAIN_LENGTH,
-                                    &al)) == NULL) {
+    if (!WPACKET_start_sub_packet_u16(&pkt)
+               /*
+                * If extensions are of zero length then we don't even add the
+                * extensions length bytes
+                */
+            || !WPACKET_set_flags(&pkt, WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH)
+            || !ssl_add_clienthello_tlsext(s, &pkt, &al)
+            || !WPACKET_close(&pkt)) {
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
-    l = p - d;
-    if (!ssl_set_handshake_header(s, SSL3_MT_CLIENT_HELLO, l)) {
+    if (!ssl_close_construct_packet(s, &pkt)) {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -869,6 +866,7 @@ int tls_construct_client_hello(SSL *s)
     return 1;
  err:
     ossl_statem_set_error(s);
+    WPACKET_cleanup(&pkt);
     return 0;
 }
 
@@ -879,7 +877,7 @@ MSG_PROCESS_RETURN dtls_process_hello_verify(SSL *s, PACKET *pkt)
     PACKET cookiepkt;
 
     if (!PACKET_forward(pkt, 2)
-            || !PACKET_get_length_prefixed_1(pkt, &cookiepkt)) {
+        || !PACKET_get_length_prefixed_1(pkt, &cookiepkt)) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_DTLS_PROCESS_HELLO_VERIFY, SSL_R_LENGTH_MISMATCH);
         goto f_err;
@@ -1143,7 +1141,6 @@ MSG_PROCESS_RETURN tls_process_server_hello(SSL *s, PACKET *pkt)
         SSLerr(SSL_F_TLS_PROCESS_SERVER_HELLO, SSL_R_BAD_PACKET_LENGTH);
         goto f_err;
     }
-
 #ifndef OPENSSL_NO_SCTP
     if (SSL_IS_DTLS(s) && s->hit) {
         unsigned char sctpauthkey[64];
@@ -1157,10 +1154,9 @@ MSG_PROCESS_RETURN tls_process_server_hello(SSL *s, PACKET *pkt)
                sizeof(DTLS1_SCTP_AUTH_LABEL));
 
         if (SSL_export_keying_material(s, sctpauthkey,
-                                   sizeof(sctpauthkey),
-                                   labelbuffer,
-                                   sizeof(labelbuffer), NULL, 0,
-                                   0) <= 0)
+                                       sizeof(sctpauthkey),
+                                       labelbuffer,
+                                       sizeof(labelbuffer), NULL, 0, 0) <= 0)
             goto err;
 
         BIO_ctrl(SSL_get_wbio(s),
@@ -1192,14 +1188,14 @@ MSG_PROCESS_RETURN tls_process_server_certificate(SSL *s, PACKET *pkt)
     }
 
     if (!PACKET_get_net_3(pkt, &cert_list_len)
-            || PACKET_remaining(pkt) != cert_list_len) {
+        || PACKET_remaining(pkt) != cert_list_len) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_SERVER_CERTIFICATE, SSL_R_LENGTH_MISMATCH);
         goto f_err;
     }
     while (PACKET_remaining(pkt)) {
         if (!PACKET_get_net_3(pkt, &cert_len)
-                || !PACKET_get_bytes(pkt, &certbytes, cert_len)) {
+            || !PACKET_get_bytes(pkt, &certbytes, cert_len)) {
             al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_SERVER_CERTIFICATE,
                    SSL_R_CERT_LENGTH_MISMATCH);
@@ -1272,9 +1268,9 @@ MSG_PROCESS_RETURN tls_process_server_certificate(SSL *s, PACKET *pkt)
 
     exp_idx = ssl_cipher_get_cert_index(s->s3->tmp.new_cipher);
     if (exp_idx >= 0 && i != exp_idx
-            && (exp_idx != SSL_PKEY_GOST_EC ||
-                (i != SSL_PKEY_GOST12_512 && i != SSL_PKEY_GOST12_256
-                 && i != SSL_PKEY_GOST01))) {
+        && (exp_idx != SSL_PKEY_GOST_EC ||
+            (i != SSL_PKEY_GOST12_512 && i != SSL_PKEY_GOST12_256
+             && i != SSL_PKEY_GOST01))) {
         x = NULL;
         al = SSL_AD_ILLEGAL_PARAMETER;
         SSLerr(SSL_F_TLS_PROCESS_SERVER_CERTIFICATE,
@@ -1311,7 +1307,7 @@ static int tls_process_ske_psk_preamble(SSL *s, PACKET *pkt, int *al)
 
     if (!PACKET_get_length_prefixed_2(pkt, &psk_identity_hint)) {
         *al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_PSK_PREAMBLE, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
 
@@ -1323,7 +1319,7 @@ static int tls_process_ske_psk_preamble(SSL *s, PACKET *pkt, int *al)
      */
     if (PACKET_remaining(&psk_identity_hint) > PSK_MAX_IDENTITY_LEN) {
         *al = SSL_AD_HANDSHAKE_FAILURE;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_DATA_LENGTH_TOO_LONG);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_PSK_PREAMBLE, SSL_R_DATA_LENGTH_TOO_LONG);
         return 0;
     }
 
@@ -1331,14 +1327,14 @@ static int tls_process_ske_psk_preamble(SSL *s, PACKET *pkt, int *al)
         OPENSSL_free(s->session->psk_identity_hint);
         s->session->psk_identity_hint = NULL;
     } else if (!PACKET_strndup(&psk_identity_hint,
-                        &s->session->psk_identity_hint)) {
+                               &s->session->psk_identity_hint)) {
         *al = SSL_AD_INTERNAL_ERROR;
         return 0;
     }
 
     return 1;
 #else
-    SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+    SSLerr(SSL_F_TLS_PROCESS_SKE_PSK_PREAMBLE, ERR_R_INTERNAL_ERROR);
     *al = SSL_AD_INTERNAL_ERROR;
     return 0;
 #endif
@@ -1354,7 +1350,7 @@ static int tls_process_ske_srp(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
         || !PACKET_get_length_prefixed_1(pkt, &salt)
         || !PACKET_get_length_prefixed_2(pkt, &server_pub)) {
         *al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_SRP, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
 
@@ -1371,23 +1367,23 @@ static int tls_process_ske_srp(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
             BN_bin2bn(PACKET_data(&server_pub),
                       PACKET_remaining(&server_pub), NULL)) == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_SRP, ERR_R_BN_LIB);
         return 0;
     }
 
     if (!srp_verify_server_param(s, al)) {
         *al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_SRP_PARAMETERS);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_SRP, SSL_R_BAD_SRP_PARAMETERS);
         return 0;
     }
 
     /* We must check if there is a certificate */
-    if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aRSA|SSL_aDSS))
+    if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aRSA | SSL_aDSS))
         *pkey = X509_get0_pubkey(s->session->peer);
 
     return 1;
 #else
-    SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+    SSLerr(SSL_F_TLS_PROCESS_SKE_SRP, ERR_R_INTERNAL_ERROR);
     *al = SSL_AD_INTERNAL_ERROR;
     return 0;
 #endif
@@ -1406,7 +1402,7 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
         || !PACKET_get_length_prefixed_2(pkt, &generator)
         || !PACKET_get_length_prefixed_2(pkt, &pub_key)) {
         *al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
 
@@ -1415,50 +1411,49 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
 
     if (peer_tmp == NULL || dh == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_MALLOC_FAILURE);
         goto err;
     }
 
     p = BN_bin2bn(PACKET_data(&prime), PACKET_remaining(&prime), NULL);
-    g = BN_bin2bn(PACKET_data(&generator), PACKET_remaining(&generator),
-                  NULL);
+    g = BN_bin2bn(PACKET_data(&generator), PACKET_remaining(&generator), NULL);
     bnpub_key = BN_bin2bn(PACKET_data(&pub_key), PACKET_remaining(&pub_key),
                           NULL);
     if (p == NULL || g == NULL || bnpub_key == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_BN_LIB);
         goto err;
     }
 
     if (BN_is_zero(p) || BN_is_zero(g) || BN_is_zero(bnpub_key)) {
         *al = SSL_AD_DECODE_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_DH_VALUE);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, SSL_R_BAD_DH_VALUE);
         goto err;
     }
 
     if (!DH_set0_pqg(dh, p, NULL, g)) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_BN_LIB);
         goto err;
     }
     p = g = NULL;
 
     if (!DH_set0_key(dh, bnpub_key, NULL)) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_BN_LIB);
         goto err;
     }
     bnpub_key = NULL;
 
     if (!ssl_security(s, SSL_SECOP_TMP_DH, DH_security_bits(dh), 0, dh)) {
         *al = SSL_AD_HANDSHAKE_FAILURE;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_DH_KEY_TOO_SMALL);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, SSL_R_DH_KEY_TOO_SMALL);
         goto err;
     }
 
     if (EVP_PKEY_assign_DH(peer_tmp, dh) == 0) {
         *al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);
+        SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_EVP_LIB);
         goto err;
     }
 
@@ -1468,7 +1463,7 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
      * FIXME: This makes assumptions about which ciphersuites come with
      * public keys. We should have a less ad-hoc way of doing this
      */
-    if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aRSA|SSL_aDSS))
+    if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aRSA | SSL_aDSS))
         *pkey = X509_get0_pubkey(s->session->peer);
     /* else anonymous DH, so no certificate or pkey. */
 
@@ -1483,7 +1478,104 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
 
     return 0;
 #else
-    SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+    SSLerr(SSL_F_TLS_PROCESS_SKE_DHE, ERR_R_INTERNAL_ERROR);
+    *al = SSL_AD_INTERNAL_ERROR;
+    return 0;
+#endif
+}
+
+static int tls_process_ske_ecdhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
+{
+#ifndef OPENSSL_NO_EC
+    PACKET encoded_pt;
+    const unsigned char *ecparams;
+    int curve_nid;
+    unsigned int curve_flags;
+    EVP_PKEY_CTX *pctx = NULL;
+
+    /*
+     * Extract elliptic curve parameters and the server's ephemeral ECDH
+     * public key. For now we only support named (not generic) curves and
+     * ECParameters in this case is just three bytes.
+     */
+    if (!PACKET_get_bytes(pkt, &ecparams, 3)) {
+        *al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, SSL_R_LENGTH_TOO_SHORT);
+        return 0;
+    }
+    /*
+     * Check curve is one of our preferences, if not server has sent an
+     * invalid curve. ECParameters is 3 bytes.
+     */
+    if (!tls1_check_curve(s, ecparams, 3)) {
+        *al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, SSL_R_WRONG_CURVE);
+        return 0;
+    }
+
+    curve_nid = tls1_ec_curve_id2nid(*(ecparams + 2), &curve_flags);
+
+    if (curve_nid == 0) {
+        *al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE,
+               SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
+        return 0;
+    }
+
+    if ((curve_flags & TLS_CURVE_TYPE) == TLS_CURVE_CUSTOM) {
+        EVP_PKEY *key = EVP_PKEY_new();
+
+        if (key == NULL || !EVP_PKEY_set_type(key, curve_nid)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, ERR_R_EVP_LIB);
+            EVP_PKEY_free(key);
+            return 0;
+        }
+        s->s3->peer_tmp = key;
+    } else {
+        /* Set up EVP_PKEY with named curve as parameters */
+        pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL);
+        if (pctx == NULL
+            || EVP_PKEY_paramgen_init(pctx) <= 0
+            || EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, curve_nid) <= 0
+            || EVP_PKEY_paramgen(pctx, &s->s3->peer_tmp) <= 0) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, ERR_R_EVP_LIB);
+            EVP_PKEY_CTX_free(pctx);
+            return 0;
+        }
+        EVP_PKEY_CTX_free(pctx);
+        pctx = NULL;
+    }
+
+    if (!PACKET_get_length_prefixed_1(pkt, &encoded_pt)) {
+        *al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, SSL_R_LENGTH_MISMATCH);
+        return 0;
+    }
+
+    if (!EVP_PKEY_set1_tls_encodedpoint(s->s3->peer_tmp,
+                                        PACKET_data(&encoded_pt),
+                                        PACKET_remaining(&encoded_pt))) {
+        *al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, SSL_R_BAD_ECPOINT);
+        return 0;
+    }
+
+    /*
+     * The ECC/TLS specification does not mention the use of DSA to sign
+     * ECParameters in the server key exchange message. We do support RSA
+     * and ECDSA.
+     */
+    if (s->s3->tmp.new_cipher->algorithm_auth & SSL_aECDSA)
+        *pkey = X509_get0_pubkey(s->session->peer);
+    else if (s->s3->tmp.new_cipher->algorithm_auth & SSL_aRSA)
+        *pkey = X509_get0_pubkey(s->session->peer);
+    /* else anonymous ECDH, so no certificate or pkey. */
+
+    return 1;
+#else
+    SSLerr(SSL_F_TLS_PROCESS_SKE_ECDHE, ERR_R_INTERNAL_ERROR);
     *al = SSL_AD_INTERNAL_ERROR;
     return 0;
 #endif
@@ -1491,19 +1583,11 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
 
 MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
 {
-    EVP_MD_CTX *md_ctx;
     int al = -1;
-    long alg_k, alg_a;
+    long alg_k;
     EVP_PKEY *pkey = NULL;
     PACKET save_param_start, signature;
 
-    md_ctx = EVP_MD_CTX_new();
-    if (md_ctx == NULL) {
-        al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
-        goto f_err;
-    }
-
     alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 
     save_param_start = *pkt;
@@ -1513,8 +1597,6 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
     s->s3->peer_tmp = NULL;
 #endif
 
-    alg_a = s->s3->tmp.new_cipher->algorithm_auth;
-
     if (alg_k & SSL_PSK) {
         if (!tls_process_ske_psk_preamble(s, pkt, &al))
             goto err;
@@ -1528,93 +1610,22 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
     } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
         if (!tls_process_ske_dhe(s, pkt, &pkey, &al))
             goto err;
-    }
-#ifndef OPENSSL_NO_EC
-    else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
-        PACKET encoded_pt;
-        const unsigned char *ecparams;
-        int curve_nid;
-        EVP_PKEY_CTX *pctx = NULL;
-
-        /*
-         * Extract elliptic curve parameters and the server's ephemeral ECDH
-         * public key. For now we only support named (not generic) curves and
-         * ECParameters in this case is just three bytes.
-         */
-        if (!PACKET_get_bytes(pkt, &ecparams, 3)) {
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
-            goto f_err;
-        }
-        /*
-         * Check curve is one of our preferences, if not server has sent an
-         * invalid curve. ECParameters is 3 bytes.
-         */
-        if (!tls1_check_curve(s, ecparams, 3)) {
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_WRONG_CURVE);
-            goto f_err;
-        }
-
-        curve_nid = tls1_ec_curve_id2nid(*(ecparams + 2));
-        if (curve_nid  == 0) {
-            al = SSL_AD_INTERNAL_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE,
-                   SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
-            goto f_err;
-        }
-
-        /* Set up EVP_PKEY with named curve as parameters */
-        pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_EC, NULL);
-        if (pctx == NULL
-            || EVP_PKEY_paramgen_init(pctx) <= 0
-            || EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, curve_nid) <= 0
-            || EVP_PKEY_paramgen(pctx, &s->s3->peer_tmp) <= 0) {
-            al = SSL_AD_INTERNAL_ERROR;
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);
-            EVP_PKEY_CTX_free(pctx);
-            goto f_err;
-        }
-        EVP_PKEY_CTX_free(pctx);
-        pctx = NULL;
-
-        if (!PACKET_get_length_prefixed_1(pkt, &encoded_pt)) {
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
-            goto f_err;
-        }
-
-        if (EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(s->s3->peer_tmp),
-                           PACKET_data(&encoded_pt),
-                           PACKET_remaining(&encoded_pt), NULL) == 0) {
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
-            goto f_err;
-        }
-
-        /*
-         * The ECC/TLS specification does not mention the use of DSA to sign
-         * ECParameters in the server key exchange message. We do support RSA
-         * and ECDSA.
-         */
-        if (0) ;
-# ifndef OPENSSL_NO_RSA
-        else if (alg_a & SSL_aRSA)
-            pkey = X509_get0_pubkey(s->session->peer);
-# endif
-# ifndef OPENSSL_NO_EC
-        else if (alg_a & SSL_aECDSA)
-            pkey = X509_get0_pubkey(s->session->peer);
-# endif
-        /* else anonymous ECDH, so no certificate or pkey. */
+    } else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
+        if (!tls_process_ske_ecdhe(s, pkt, &pkey, &al))
+            goto err;
     } else if (alg_k) {
         al = SSL_AD_UNEXPECTED_MESSAGE;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_UNEXPECTED_MESSAGE);
-        goto f_err;
+        goto err;
     }
-#endif                          /* !OPENSSL_NO_EC */
 
     /* if it was signed, check the signature */
     if (pkey != NULL) {
         PACKET params;
         int maxsig;
         const EVP_MD *md = NULL;
+        EVP_MD_CTX *md_ctx;
+
         /*
          * |pkt| now points to the beginning of the signature, so the difference
          * equals the length of the parameters.
@@ -1624,21 +1635,24 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
                                    PACKET_remaining(pkt))) {
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
-            goto f_err;
+            goto err;
         }
 
         if (SSL_USE_SIGALGS(s)) {
             const unsigned char *sigalgs;
             int rv;
             if (!PACKET_get_bytes(pkt, &sigalgs, 2)) {
+                al = SSL_AD_DECODE_ERROR;
                 SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
-                goto f_err;
+                goto err;
             }
             rv = tls12_check_peer_sigalg(&md, s, sigalgs, pkey);
-            if (rv == -1)
+            if (rv == -1) {
+                al = SSL_AD_INTERNAL_ERROR;
+                goto err;
+            } else if (rv == 0) {
+                al = SSL_AD_DECODE_ERROR;
                 goto err;
-            else if (rv == 0) {
-                goto f_err;
             }
 #ifdef SSL_DEBUG
             fprintf(stderr, "USING TLSv1.2 HASH %s\n", EVP_MD_name(md));
@@ -1651,13 +1665,15 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
 
         if (!PACKET_get_length_prefixed_2(pkt, &signature)
             || PACKET_remaining(pkt) != 0) {
+            al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
-            goto f_err;
+            goto err;
         }
         maxsig = EVP_PKEY_size(pkey);
         if (maxsig < 0) {
+            al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
-            goto f_err;
+            goto err;
         }
 
         /*
@@ -1665,51 +1681,66 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
          */
         if (PACKET_remaining(&signature) > (size_t)maxsig) {
             /* wrong packet length */
-            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_WRONG_SIGNATURE_LENGTH);
-            goto f_err;
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE,
+                   SSL_R_WRONG_SIGNATURE_LENGTH);
+            goto err;
         }
+
+        md_ctx = EVP_MD_CTX_new();
+        if (md_ctx == NULL) {
+            al = SSL_AD_INTERNAL_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+            goto err;
+        }
+
         if (EVP_VerifyInit_ex(md_ctx, md, NULL) <= 0
-                || EVP_VerifyUpdate(md_ctx, &(s->s3->client_random[0]),
-                                    SSL3_RANDOM_SIZE) <= 0
-                || EVP_VerifyUpdate(md_ctx, &(s->s3->server_random[0]),
-                                    SSL3_RANDOM_SIZE) <= 0
-                || EVP_VerifyUpdate(md_ctx, PACKET_data(&params),
-                                    PACKET_remaining(&params)) <= 0) {
+            || EVP_VerifyUpdate(md_ctx, &(s->s3->client_random[0]),
+                                SSL3_RANDOM_SIZE) <= 0
+            || EVP_VerifyUpdate(md_ctx, &(s->s3->server_random[0]),
+                                SSL3_RANDOM_SIZE) <= 0
+            || EVP_VerifyUpdate(md_ctx, PACKET_data(&params),
+                                PACKET_remaining(&params)) <= 0) {
+            EVP_MD_CTX_free(md_ctx);
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);
-            goto f_err;
+            goto err;
         }
         if (EVP_VerifyFinal(md_ctx, PACKET_data(&signature),
                             PACKET_remaining(&signature), pkey) <= 0) {
             /* bad signature */
+            EVP_MD_CTX_free(md_ctx);
             al = SSL_AD_DECRYPT_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_SIGNATURE);
-            goto f_err;
+            goto err;
         }
+        EVP_MD_CTX_free(md_ctx);
     } else {
         /* aNULL, aSRP or PSK do not need public keys */
-        if (!(alg_a & (SSL_aNULL | SSL_aSRP)) && !(alg_k & SSL_PSK)) {
+        if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aSRP))
+            && !(alg_k & SSL_PSK)) {
             /* Might be wrong key type, check it */
-            if (ssl3_check_cert_and_algorithm(s))
+            if (ssl3_check_cert_and_algorithm(s)) {
                 /* Otherwise this shouldn't happen */
+                al = SSL_AD_INTERNAL_ERROR;
                 SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+            } else {
+                al = SSL_AD_DECODE_ERROR;
+            }
             goto err;
         }
         /* still data left over */
         if (PACKET_remaining(pkt) != 0) {
+            al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_EXTRA_DATA_IN_MESSAGE);
-            goto f_err;
+            goto err;
         }
     }
-    EVP_MD_CTX_free(md_ctx);
+
     return MSG_PROCESS_CONTINUE_READING;
- f_err:
-    if (al == -1)
-        al = SSL_AD_DECODE_ERROR;
  err:
     if (al != -1)
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
-    EVP_MD_CTX_free(md_ctx);
     ossl_statem_set_error(s);
     return MSG_PROCESS_ERROR;
 }
@@ -1730,7 +1761,7 @@ MSG_PROCESS_RETURN tls_process_certificate_request(SSL *s, PACKET *pkt)
 
     /* get the certificate types */
     if (!PACKET_get_1(pkt, &ctype_num)
-            || !PACKET_get_bytes(pkt, &data, ctype_num)) {
+        || !PACKET_get_bytes(pkt, &data, ctype_num)) {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
         SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, SSL_R_LENGTH_MISMATCH);
         goto err;
@@ -1753,7 +1784,7 @@ MSG_PROCESS_RETURN tls_process_certificate_request(SSL *s, PACKET *pkt)
 
     if (SSL_USE_SIGALGS(s)) {
         if (!PACKET_get_net_2(pkt, &list_len)
-                || !PACKET_get_bytes(pkt, &data, list_len)) {
+            || !PACKET_get_bytes(pkt, &data, list_len)) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
             SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
                    SSL_R_LENGTH_MISMATCH);
@@ -1782,7 +1813,7 @@ MSG_PROCESS_RETURN tls_process_certificate_request(SSL *s, PACKET *pkt)
 
     /* get the CA RDNs */
     if (!PACKET_get_net_2(pkt, &list_len)
-            || PACKET_remaining(pkt) != list_len) {
+        || PACKET_remaining(pkt) != list_len) {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
         SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, SSL_R_LENGTH_MISMATCH);
         goto err;
@@ -1790,7 +1821,7 @@ MSG_PROCESS_RETURN tls_process_certificate_request(SSL *s, PACKET *pkt)
 
     while (PACKET_remaining(pkt)) {
         if (!PACKET_get_net_2(pkt, &name_len)
-                || !PACKET_get_bytes(pkt, &namebytes, name_len)) {
+            || !PACKET_get_bytes(pkt, &namebytes, name_len)) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
             SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
                    SSL_R_LENGTH_MISMATCH);
@@ -1848,8 +1879,8 @@ MSG_PROCESS_RETURN tls_process_new_session_ticket(SSL *s, PACKET *pkt)
     unsigned long ticket_lifetime_hint;
 
     if (!PACKET_get_net_4(pkt, &ticket_lifetime_hint)
-            || !PACKET_get_net_2(pkt, &ticklen)
-            || PACKET_remaining(pkt) != ticklen) {
+        || !PACKET_get_net_2(pkt, &ticklen)
+        || PACKET_remaining(pkt) != ticklen) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_NEW_SESSION_TICKET, SSL_R_LENGTH_MISMATCH);
         goto f_err;
@@ -1931,13 +1962,13 @@ MSG_PROCESS_RETURN tls_process_cert_status(SSL *s, PACKET *pkt)
     unsigned int type;
 
     if (!PACKET_get_1(pkt, &type)
-            || type != TLSEXT_STATUSTYPE_ocsp) {
+        || type != TLSEXT_STATUSTYPE_ocsp) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CERT_STATUS, SSL_R_UNSUPPORTED_STATUS_TYPE);
         goto f_err;
     }
     if (!PACKET_get_net_3(pkt, &resplen)
-            || PACKET_remaining(pkt) != resplen) {
+        || PACKET_remaining(pkt) != resplen) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CERT_STATUS, SSL_R_LENGTH_MISMATCH);
         goto f_err;
@@ -1970,7 +2001,6 @@ MSG_PROCESS_RETURN tls_process_server_done(SSL *s, PACKET *pkt)
         ossl_statem_set_error(s);
         return MSG_PROCESS_ERROR;
     }
-
 #ifndef OPENSSL_NO_SRP
     if (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kSRP) {
         if (SRP_Calc_A_param(s) <= 0) {
@@ -2013,7 +2043,6 @@ MSG_PROCESS_RETURN tls_process_server_done(SSL *s, PACKET *pkt)
             return MSG_PROCESS_ERROR;
         }
     }
-
 #ifndef OPENSSL_NO_CT
     if (s->ct_validation_callback != NULL) {
         /* Note we validate the SCTs whether or not we abort on error */
@@ -2027,15 +2056,14 @@ MSG_PROCESS_RETURN tls_process_server_done(SSL *s, PACKET *pkt)
 #ifndef OPENSSL_NO_SCTP
     /* Only applies to renegotiation */
     if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))
-            && s->renegotiate != 0)
+        && s->renegotiate != 0)
         return MSG_PROCESS_CONTINUE_PROCESSING;
     else
 #endif
         return MSG_PROCESS_FINISHED_READING;
 }
 
-static int tls_construct_cke_psk_preamble(SSL *s, unsigned char **p,
-                                          size_t *pskhdrlen, int *al)
+static int tls_construct_cke_psk_preamble(SSL *s, WPACKET *pkt, int *al)
 {
 #ifndef OPENSSL_NO_PSK
     int ret = 0;
@@ -2096,10 +2124,12 @@ static int tls_construct_cke_psk_preamble(SSL *s, unsigned char **p,
     OPENSSL_free(s->session->psk_identity);
     s->session->psk_identity = tmpidentity;
     tmpidentity = NULL;
-    s2n(identitylen, *p);
-    memcpy(*p, identity, identitylen);
-    *pskhdrlen = 2 + identitylen;
-    *p += identitylen;
+
+    if (!WPACKET_sub_memcpy_u16(pkt, identity, identitylen))  {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_PSK_PREAMBLE, ERR_R_INTERNAL_ERROR);
+        *al = SSL_AD_INTERNAL_ERROR;
+        goto err;
+    }
 
     ret = 1;
 
@@ -2117,10 +2147,10 @@ static int tls_construct_cke_psk_preamble(SSL *s, unsigned char **p,
 #endif
 }
 
-static int tls_construct_cke_rsa(SSL *s, unsigned char **p, int *len, int *al)
+static int tls_construct_cke_rsa(SSL *s, WPACKET *pkt, int *al)
 {
 #ifndef OPENSSL_NO_RSA
-    unsigned char *q;
+    unsigned char *encdata = NULL;
     EVP_PKEY *pkey = NULL;
     EVP_PKEY_CTX *pctx = NULL;
     size_t enclen;
@@ -2155,21 +2185,22 @@ static int tls_construct_cke_rsa(SSL *s, unsigned char **p, int *len, int *al)
         goto err;
     }
 
-    q = *p;
     /* Fix buf for TLS and beyond */
-    if (s->version > SSL3_VERSION)
-        *p += 2;
+    if (s->version > SSL3_VERSION && !WPACKET_start_sub_packet_u16(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_RSA, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
     pctx = EVP_PKEY_CTX_new(pkey, NULL);
     if (pctx == NULL || EVP_PKEY_encrypt_init(pctx) <= 0
         || EVP_PKEY_encrypt(pctx, NULL, &enclen, pms, pmslen) <= 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_RSA, ERR_R_EVP_LIB);
         goto err;
     }
-    if (EVP_PKEY_encrypt(pctx, *p, &enclen, pms, pmslen) <= 0) {
+    if (!WPACKET_allocate_bytes(pkt, enclen, &encdata)
+            || EVP_PKEY_encrypt(pctx, encdata, &enclen, pms, pmslen) <= 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_RSA, SSL_R_BAD_RSA_ENCRYPT);
         goto err;
     }
-    *len = enclen;
     EVP_PKEY_CTX_free(pctx);
     pctx = NULL;
 # ifdef PKCS1_CHECK
@@ -2180,9 +2211,9 @@ static int tls_construct_cke_rsa(SSL *s, unsigned char **p, int *len, int *al)
 # endif
 
     /* Fix buf for TLS and beyond */
-    if (s->version > SSL3_VERSION) {
-        s2n(*len, q);
-        *len += 2;
+    if (s->version > SSL3_VERSION && !WPACKET_close(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_RSA, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
 
     s->s3->tmp.pms = pms;
@@ -2201,57 +2232,56 @@ static int tls_construct_cke_rsa(SSL *s, unsigned char **p, int *len, int *al)
 #endif
 }
 
-static int tls_construct_cke_dhe(SSL *s, unsigned char **p, int *len, int *al)
+static int tls_construct_cke_dhe(SSL *s, WPACKET *pkt, int *al)
 {
 #ifndef OPENSSL_NO_DH
     DH *dh_clnt = NULL;
     const BIGNUM *pub_key;
     EVP_PKEY *ckey = NULL, *skey = NULL;
+    unsigned char *keybytes = NULL;
 
     skey = s->s3->peer_tmp;
-    if (skey == NULL) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_DHE, ERR_R_INTERNAL_ERROR);
-        return 0;
-    }
-    ckey = ssl_generate_pkey(skey, NID_undef);
+    if (skey == NULL)
+        goto err;
+
+    ckey = ssl_generate_pkey(skey);
     dh_clnt = EVP_PKEY_get0_DH(ckey);
 
-    if (dh_clnt == NULL || ssl_derive(s, ckey, skey) == 0) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_DHE, ERR_R_INTERNAL_ERROR);
-        EVP_PKEY_free(ckey);
-        return 0;
-    }
+    if (dh_clnt == NULL || ssl_derive(s, ckey, skey) == 0)
+        goto err;
 
     /* send off the data */
     DH_get0_key(dh_clnt, &pub_key, NULL);
-    *len = BN_num_bytes(pub_key);
-    s2n(*len, *p);
-    BN_bn2bin(pub_key, *p);
-    *len += 2;
+    if (!WPACKET_sub_allocate_bytes_u16(pkt, BN_num_bytes(pub_key), &keybytes))
+        goto err;
+
+    BN_bn2bin(pub_key, keybytes);
     EVP_PKEY_free(ckey);
 
     return 1;
-#else
+ err:
+    EVP_PKEY_free(ckey);
+#endif
     SSLerr(SSL_F_TLS_CONSTRUCT_CKE_DHE, ERR_R_INTERNAL_ERROR);
     *al = SSL_AD_INTERNAL_ERROR;
     return 0;
-#endif
 }
 
-static int tls_construct_cke_ecdhe(SSL *s, unsigned char **p, int *len, int *al)
+static int tls_construct_cke_ecdhe(SSL *s, WPACKET *pkt, int *al)
 {
 #ifndef OPENSSL_NO_EC
     unsigned char *encodedPoint = NULL;
     int encoded_pt_len = 0;
     EVP_PKEY *ckey = NULL, *skey = NULL;
+    int ret = 0;
 
     skey = s->s3->peer_tmp;
-    if ((skey == NULL) || EVP_PKEY_get0_EC_KEY(skey) == NULL) {
+    if (skey == NULL) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_ECDHE, ERR_R_INTERNAL_ERROR);
         return 0;
     }
 
-    ckey = ssl_generate_pkey(skey, NID_undef);
+    ckey = ssl_generate_pkey(skey);
 
     if (ssl_derive(s, ckey, skey) == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_ECDHE, ERR_R_EVP_LIB);
@@ -2259,34 +2289,23 @@ static int tls_construct_cke_ecdhe(SSL *s, unsigned char **p, int *len, int *al)
     }
 
     /* Generate encoding of client key */
-    encoded_pt_len = EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(ckey),
-                                    POINT_CONVERSION_UNCOMPRESSED,
-                                    &encodedPoint, NULL);
+    encoded_pt_len = EVP_PKEY_get1_tls_encodedpoint(ckey, &encodedPoint);
 
     if (encoded_pt_len == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_ECDHE, ERR_R_EC_LIB);
         goto err;
     }
 
-    EVP_PKEY_free(ckey);
-    ckey = NULL;
-
-    *len = encoded_pt_len;
-
-    /* length of encoded point */
-    **p = *len;
-    *p += 1;
-    /* copy the point */
-    memcpy(*p, encodedPoint, *len);
-    /* increment len to account for length field */
-    *len += 1;
-
-    OPENSSL_free(encodedPoint);
+    if (!WPACKET_sub_memcpy_u8(pkt, encodedPoint, encoded_pt_len)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_ECDHE, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
-    return 1;
+    ret = 1;
  err:
+    OPENSSL_free(encodedPoint);
     EVP_PKEY_free(ckey);
-    return 0;
+    return ret;
 #else
     SSLerr(SSL_F_TLS_CONSTRUCT_CKE_ECDHE, ERR_R_INTERNAL_ERROR);
     *al = SSL_AD_INTERNAL_ERROR;
@@ -2294,7 +2313,7 @@ static int tls_construct_cke_ecdhe(SSL *s, unsigned char **p, int *len, int *al)
 #endif
 }
 
-static int tls_construct_cke_gost(SSL *s, unsigned char **p, int *len, int *al)
+static int tls_construct_cke_gost(SSL *s, WPACKET *pkt, int *al)
 {
 #ifndef OPENSSL_NO_GOST
     /* GOST key exchange message creation */
@@ -2340,41 +2359,28 @@ static int tls_construct_cke_gost(SSL *s, unsigned char **p, int *len, int *al)
     if (pms == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_GOST, ERR_R_MALLOC_FAILURE);
-        return 0;
+        goto err;
     }
 
     if (EVP_PKEY_encrypt_init(pkey_ctx) <= 0
-            /* Generate session key */
-            || RAND_bytes(pms, pmslen) <= 0) {
+        /* Generate session key */
+        || RAND_bytes(pms, pmslen) <= 0) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_GOST, ERR_R_INTERNAL_ERROR);
         goto err;
     };
-    /*
-     * If we have client certificate, use its secret as peer key
-     */
-    if (s->s3->tmp.cert_req && s->cert->key->privatekey) {
-        if (EVP_PKEY_derive_set_peer
-            (pkey_ctx, s->cert->key->privatekey) <= 0) {
-            /*
-             * If there was an error - just ignore it. Ephemeral key
-             * * would be used
-             */
-            ERR_clear_error();
-        }
-    }
     /*
      * Compute shared IV and store it in algorithm-specific context
      * data
      */
     ukm_hash = EVP_MD_CTX_new();
     if (ukm_hash == NULL
-            || EVP_DigestInit(ukm_hash, EVP_get_digestbynid(dgst_nid)) <= 0
-            || EVP_DigestUpdate(ukm_hash, s->s3->client_random,
-                                SSL3_RANDOM_SIZE) <= 0
-            || EVP_DigestUpdate(ukm_hash, s->s3->server_random,
-                                SSL3_RANDOM_SIZE) <= 0
-            || EVP_DigestFinal_ex(ukm_hash, shared_ukm, &md_len) <= 0) {
+        || EVP_DigestInit(ukm_hash, EVP_get_digestbynid(dgst_nid)) <= 0
+        || EVP_DigestUpdate(ukm_hash, s->s3->client_random,
+                            SSL3_RANDOM_SIZE) <= 0
+        || EVP_DigestUpdate(ukm_hash, s->s3->server_random,
+                            SSL3_RANDOM_SIZE) <= 0
+        || EVP_DigestFinal_ex(ukm_hash, shared_ukm, &md_len) <= 0) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_GOST, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -2391,28 +2397,21 @@ static int tls_construct_cke_gost(SSL *s, unsigned char **p, int *len, int *al)
     /*
      * Encapsulate it into sequence
      */
-    *((*p)++) = V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED;
     msglen = 255;
     if (EVP_PKEY_encrypt(pkey_ctx, tmp, &msglen, pms, pmslen) <= 0) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_GOST, SSL_R_LIBRARY_BUG);
         goto err;
     }
-    if (msglen >= 0x80) {
-        *((*p)++) = 0x81;
-        *((*p)++) = msglen & 0xff;
-        *len = msglen + 3;
-    } else {
-        *((*p)++) = msglen & 0xff;
-        *len = msglen + 2;
-    }
-    memcpy(*p, tmp, msglen);
-    /* Check if pubkey from client certificate was used */
-    if (EVP_PKEY_CTX_ctrl(pkey_ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 2,
-                          NULL) > 0) {
-        /* Set flag "skip certificate verify" */
-        s->s3->flags |= TLS1_FLAGS_SKIP_CERT_VERIFY;
+
+    if (!WPACKET_put_bytes_u8(pkt, V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)
+            || (msglen >= 0x80 && !WPACKET_put_bytes_u8(pkt, 0x81))
+            || !WPACKET_sub_memcpy_u8(pkt, tmp, msglen)) {
+        *al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_CONSTRUCT_CKE_GOST, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
+
     EVP_PKEY_CTX_free(pkey_ctx);
     s->s3->tmp.pms = pms;
     s->s3->tmp.pmslen = pmslen;
@@ -2430,19 +2429,19 @@ static int tls_construct_cke_gost(SSL *s, unsigned char **p, int *len, int *al)
 #endif
 }
 
-static int tls_construct_cke_srp(SSL *s, unsigned char **p, int *len, int *al)
+static int tls_construct_cke_srp(SSL *s, WPACKET *pkt, int *al)
 {
-#ifndef OPENSSL_NO_SRT
-    if (s->srp_ctx.A != NULL) {
-        /* send off the data */
-        *len = BN_num_bytes(s->srp_ctx.A);
-        s2n(*len, *p);
-        BN_bn2bin(s->srp_ctx.A, *p);
-        *len += 2;
-    } else {
+#ifndef OPENSSL_NO_SRP
+    unsigned char *abytes = NULL;
+
+    if (s->srp_ctx.A == NULL
+            || !WPACKET_sub_allocate_bytes_u16(pkt, BN_num_bytes(s->srp_ctx.A),
+                                               &abytes)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CKE_SRP, ERR_R_INTERNAL_ERROR);
         return 0;
     }
+    BN_bn2bin(s->srp_ctx.A, abytes);
+
     OPENSSL_free(s->session->srp_username);
     s->session->srp_username = OPENSSL_strdup(s->srp_ctx.login);
     if (s->session->srp_username == NULL) {
@@ -2460,36 +2459,42 @@ static int tls_construct_cke_srp(SSL *s, unsigned char **p, int *len, int *al)
 
 int tls_construct_client_key_exchange(SSL *s)
 {
-    unsigned char *p;
-    int len;
-    size_t pskhdrlen = 0;
     unsigned long alg_k;
     int al = -1;
+    WPACKET pkt;
 
-    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
+    if (!WPACKET_init(&pkt, s->init_buf)) {
+        /* Should not happen */
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
-    p = ssl_handshake_start(s);
+    if (!ssl_set_handshake_header2(s, &pkt, SSL3_MT_CLIENT_KEY_EXCHANGE)) {
+        ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 
     if ((alg_k & SSL_PSK)
-            && !tls_construct_cke_psk_preamble(s, &p, &pskhdrlen, &al))
+        && !tls_construct_cke_psk_preamble(s, &pkt, &al))
         goto err;
 
-    if (alg_k & SSL_kPSK) {
-        len = 0;
-    } else if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
-        if (!tls_construct_cke_rsa(s, &p, &len, &al))
+    if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
+        if (!tls_construct_cke_rsa(s, &pkt, &al))
             goto err;
     } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
-        if (!tls_construct_cke_dhe(s, &p, &len, &al))
+        if (!tls_construct_cke_dhe(s, &pkt, &al))
             goto err;
     } else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
-        if (!tls_construct_cke_ecdhe(s, &p, &len, &al))
+        if (!tls_construct_cke_ecdhe(s, &pkt, &al))
             goto err;
     } else if (alg_k & SSL_kGOST) {
-        if (!tls_construct_cke_gost(s, &p, &len, &al))
+        if (!tls_construct_cke_gost(s, &pkt, &al))
             goto err;
     } else if (alg_k & SSL_kSRP) {
-        if (!tls_construct_cke_srp(s, &p, &len, &al))
+        if (!tls_construct_cke_srp(s, &pkt, &al))
             goto err;
     } else {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
@@ -2497,9 +2502,7 @@ int tls_construct_client_key_exchange(SSL *s)
         goto err;
     }
 
-    len += pskhdrlen;
-
-    if (!ssl_set_handshake_header(s, SSL3_MT_CLIENT_KEY_EXCHANGE, len)) {
+    if (!ssl_close_construct_packet(s, &pkt)) {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -2515,6 +2518,7 @@ int tls_construct_client_key_exchange(SSL *s)
     OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
     s->s3->tmp.psk = NULL;
 #endif
+    WPACKET_cleanup(&pkt);
     ossl_statem_set_error(s);
     return 0;
 }
@@ -2568,8 +2572,8 @@ int tls_client_key_exchange_post_work(SSL *s)
                sizeof(DTLS1_SCTP_AUTH_LABEL));
 
         if (SSL_export_keying_material(s, sctpauthkey,
-                                   sizeof(sctpauthkey), labelbuffer,
-                                   sizeof(labelbuffer), NULL, 0, 0) <= 0)
+                                       sizeof(sctpauthkey), labelbuffer,
+                                       sizeof(labelbuffer), NULL, 0, 0) <= 0)
             goto err;
 
         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
@@ -2586,22 +2590,31 @@ int tls_client_key_exchange_post_work(SSL *s)
 
 int tls_construct_client_verify(SSL *s)
 {
-    unsigned char *p;
     EVP_PKEY *pkey;
     const EVP_MD *md = s->s3->tmp.md[s->cert->key - s->cert->pkeys];
-    EVP_MD_CTX *mctx;
+    EVP_MD_CTX *mctx = NULL;
     unsigned u = 0;
-    unsigned long n = 0;
     long hdatalen = 0;
     void *hdata;
+    unsigned char *sig = NULL;
+    WPACKET pkt;
+
+    if (!WPACKET_init(&pkt, s->init_buf)) {
+        /* Should not happen */
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (!ssl_set_handshake_header2(s, &pkt, SSL3_MT_CERTIFICATE_VERIFY)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     mctx = EVP_MD_CTX_new();
     if (mctx == NULL) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_MALLOC_FAILURE);
         goto err;
     }
-
-    p = ssl_handshake_start(s);
     pkey = s->cert->key->privatekey;
 
     hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
@@ -2609,24 +2622,25 @@ int tls_construct_client_verify(SSL *s)
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
         goto err;
     }
-    if (SSL_USE_SIGALGS(s)) {
-        if (!tls12_get_sigandhash(p, pkey, md)) {
-            SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
-            goto err;
-        }
-        p += 2;
-        n = 2;
+    if (SSL_USE_SIGALGS(s)&& !tls12_get_sigandhash(&pkt, pkey, md)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
 #ifdef SSL_DEBUG
     fprintf(stderr, "Using client alg %s\n", EVP_MD_name(md));
 #endif
+    sig = OPENSSL_malloc(EVP_PKEY_size(pkey));
+    if (sig == NULL) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
     if (!EVP_SignInit_ex(mctx, md, NULL)
         || !EVP_SignUpdate(mctx, hdata, hdatalen)
         || (s->version == SSL3_VERSION
             && !EVP_MD_CTX_ctrl(mctx, EVP_CTRL_SSL3_MASTER_SECRET,
                                 s->session->master_key_length,
                                 s->session->master_key))
-        || !EVP_SignFinal(mctx, p + 2, &u, pkey)) {
+        || !EVP_SignFinal(mctx, sig, &u, pkey)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_EVP_LIB);
         goto err;
     }
@@ -2636,24 +2650,32 @@ int tls_construct_client_verify(SSL *s)
         if (pktype == NID_id_GostR3410_2001
             || pktype == NID_id_GostR3410_2012_256
             || pktype == NID_id_GostR3410_2012_512)
-            BUF_reverse(p + 2, NULL, u);
+            BUF_reverse(sig, NULL, u);
     }
 #endif
 
-    s2n(u, p);
-    n += u + 2;
+    if (!WPACKET_sub_memcpy_u16(&pkt, sig, u)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
     /* Digest cached records and discard handshake buffer */
     if (!ssl3_digest_cached_records(s, 0))
         goto err;
-    if (!ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE_VERIFY, n)) {
+
+    if (!ssl_close_construct_packet(s, &pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_VERIFY, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
+    OPENSSL_free(sig);
     EVP_MD_CTX_free(mctx);
     return 1;
  err:
+    WPACKET_cleanup(&pkt);
+    OPENSSL_free(sig);
     EVP_MD_CTX_free(mctx);
+    ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
     return 0;
 }
 
@@ -2846,22 +2868,42 @@ int ssl3_check_cert_and_algorithm(SSL *s)
 #ifndef OPENSSL_NO_NEXTPROTONEG
 int tls_construct_next_proto(SSL *s)
 {
-    unsigned int len, padding_len;
-    unsigned char *d;
+    size_t len, padding_len;
+    unsigned char *padding = NULL;
+    WPACKET pkt;
+
+    if (!WPACKET_init(&pkt, s->init_buf)) {
+        /* Should not happen */
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEXT_PROTO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (!ssl_set_handshake_header2(s, &pkt, SSL3_MT_NEXT_PROTO)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEXT_PROTO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     len = s->next_proto_negotiated_len;
     padding_len = 32 - ((len + 2) % 32);
-    d = (unsigned char *)s->init_buf->data;
-    d[4] = len;
-    memcpy(d + 5, s->next_proto_negotiated, len);
-    d[5 + len] = padding_len;
-    memset(d + 6 + len, 0, padding_len);
-    *(d++) = SSL3_MT_NEXT_PROTO;
-    l2n3(2 + len + padding_len, d);
-    s->init_num = 4 + 2 + len + padding_len;
-    s->init_off = 0;
+
+    if (!WPACKET_sub_memcpy_u8(&pkt, s->next_proto_negotiated, len)
+            || !WPACKET_sub_allocate_bytes_u8(&pkt, padding_len, &padding)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEXT_PROTO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    memset(padding, 0, padding_len);
+
+    if (!ssl_close_construct_packet(s, &pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_NEXT_PROTO, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
     return 1;
+ err:
+    WPACKET_cleanup(&pkt);
+    ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+    return 0;
 }
 #endif
 
@@ -2882,48 +2924,79 @@ int ssl_do_client_cert_cb(SSL *s, X509 **px509, EVP_PKEY **ppkey)
     return i;
 }
 
-int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk,
-                             unsigned char *p)
+int ssl_cipher_list_to_bytes(SSL *s, STACK_OF(SSL_CIPHER) *sk, WPACKET *pkt)
 {
-    int i, j = 0;
-    const SSL_CIPHER *c;
-    unsigned char *q;
+    int i;
+    size_t totlen = 0, len, maxlen;
     int empty_reneg_info_scsv = !s->renegotiate;
     /* Set disabled masks for this session */
     ssl_set_client_disabled(s);
 
     if (sk == NULL)
         return (0);
-    q = p;
 
-    for (i = 0; i < sk_SSL_CIPHER_num(sk); i++) {
+#ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
+# if OPENSSL_MAX_TLS1_2_CIPHER_LENGTH < 6
+#  error Max cipher length too short
+# endif
+    /*
+     * Some servers hang if client hello > 256 bytes as hack workaround
+     * chop number of supported ciphers to keep it well below this if we
+     * use TLS v1.2
+     */
+    if (TLS1_get_version(s) >= TLS1_2_VERSION)
+        maxlen = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
+    else
+#endif
+        /* Maximum length that can be stored in 2 bytes. Length must be even */
+        maxlen = 0xfffe;
+
+    if (empty_reneg_info_scsv)
+        maxlen -= 2;
+    if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV)
+        maxlen -= 2;
+
+    for (i = 0; i < sk_SSL_CIPHER_num(sk) && totlen < maxlen; i++) {
+        const SSL_CIPHER *c;
+
         c = sk_SSL_CIPHER_value(sk, i);
         /* Skip disabled ciphers */
         if (ssl_cipher_disabled(s, c, SSL_SECOP_CIPHER_SUPPORTED))
             continue;
-        j = s->method->put_cipher_by_char(c, p);
-        p += j;
+
+        if (!s->method->put_cipher_by_char(c, pkt, &len)) {
+            SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+
+        totlen += len;
     }
-    /*
-     * If p == q, no ciphers; caller indicates an error. Otherwise, add
-     * applicable SCSVs.
-     */
-    if (p != q) {
+
+    if (totlen == 0) {
+        SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, SSL_R_NO_CIPHERS_AVAILABLE);
+        return 0;
+    }
+
+    if (totlen != 0) {
         if (empty_reneg_info_scsv) {
             static SSL_CIPHER scsv = {
                 0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
             };
-            j = s->method->put_cipher_by_char(&scsv, p);
-            p += j;
+            if (!s->method->put_cipher_by_char(&scsv, pkt, &len)) {
+                SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
         }
         if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV) {
             static SSL_CIPHER scsv = {
                 0, NULL, SSL3_CK_FALLBACK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
             };
-            j = s->method->put_cipher_by_char(&scsv, p);
-            p += j;
+            if (!s->method->put_cipher_by_char(&scsv, pkt, &len)) {
+                SSLerr(SSL_F_SSL_CIPHER_LIST_TO_BYTES, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
         }
     }
 
-    return (p - q);
+    return 1;
 }