Convert key exchange to one shot call
[openssl.git] / ssl / statem / statem_lib.c
index e7ea4c6..abdeb56 100644 (file)
@@ -1,5 +1,6 @@
 /*
  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -7,12 +8,6 @@
  * https://www.openssl.org/source/license.html
  */
 
-/* ====================================================================
- * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
- * ECC cipher suite support in OpenSSL originally developed by
- * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
- */
-
 #include <limits.h>
 #include <string.h>
 #include <stdio.h>
 int ssl3_do_write(SSL *s, int type)
 {
     int ret;
+    size_t written = 0;
 
     ret = ssl3_write_bytes(s, type, &s->init_buf->data[s->init_off],
-                           s->init_num);
+                           s->init_num, &written);
     if (ret < 0)
         return (-1);
     if (type == SSL3_RT_HANDSHAKE)
@@ -42,18 +38,18 @@ int ssl3_do_write(SSL *s, int type)
          */
         if (!ssl3_finish_mac(s,
                              (unsigned char *)&s->init_buf->data[s->init_off],
-                             ret))
+                             written))
             return -1;
 
-    if (ret == (int)s->init_num) {
+    if (written == s->init_num) {
         if (s->msg_callback)
             s->msg_callback(1, s->version, type, s->init_buf->data,
                             (size_t)(s->init_off + s->init_num), s,
                             s->msg_callback_arg);
         return (1);
     }
-    s->init_off += ret;
-    s->init_num -= ret;
+    s->init_off += written;
+    s->init_num -= written;
     return (0);
 }
 
@@ -71,11 +67,445 @@ int tls_close_construct_packet(SSL *s, WPACKET *pkt, int htype)
     return 1;
 }
 
+int tls_setup_handshake(SSL *s)
+{
+    if (!ssl3_init_finished_mac(s))
+        return 0;
+
+    /* Reset any extension flags */
+    memset(s->ext.extflags, 0, sizeof(s->ext.extflags));
+
+    if (s->server) {
+        STACK_OF(SSL_CIPHER) *ciphers = SSL_get_ciphers(s);
+        int i, ver_min, ver_max, ok = 0;
+
+        /*
+         * Sanity check that the maximum version we accept has ciphers
+         * enabled. For clients we do this check during construction of the
+         * ClientHello.
+         */
+        if (ssl_get_min_max_version(s, &ver_min, &ver_max) != 0) {
+            SSLerr(SSL_F_TLS_SETUP_HANDSHAKE, ERR_R_INTERNAL_ERROR);
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+            return 0;
+        }
+        for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
+            const SSL_CIPHER *c = sk_SSL_CIPHER_value(ciphers, i);
+
+            if (SSL_IS_DTLS(s)) {
+                if (DTLS_VERSION_GE(ver_max, c->min_dtls) &&
+                        DTLS_VERSION_LE(ver_max, c->max_dtls))
+                    ok = 1;
+            } else if (ver_max >= c->min_tls && ver_max <= c->max_tls) {
+                ok = 1;
+            }
+            if (ok)
+                break;
+        }
+        if (!ok) {
+            SSLerr(SSL_F_TLS_SETUP_HANDSHAKE, SSL_R_NO_CIPHERS_AVAILABLE);
+            ERR_add_error_data(1, "No ciphers enabled for max supported "
+                                  "SSL/TLS version");
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+            return 0;
+        }
+        if (SSL_IS_FIRST_HANDSHAKE(s)) {
+            s->ctx->stats.sess_accept++;
+        } else if ((s->options & SSL_OP_NO_RENEGOTIATION)) {
+            /* Renegotiation is disabled */
+            ssl3_send_alert(s, SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
+            return 0;
+        } else if (!s->s3->send_connection_binding &&
+                   !(s->options &
+                     SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
+            /*
+             * Server attempting to renegotiate with client that doesn't
+             * support secure renegotiation.
+             */
+            SSLerr(SSL_F_TLS_SETUP_HANDSHAKE,
+                   SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+            return 0;
+        } else {
+            s->ctx->stats.sess_accept_renegotiate++;
+
+            s->s3->tmp.cert_request = 0;
+        }
+    } else {
+        if (SSL_IS_FIRST_HANDSHAKE(s))
+            s->ctx->stats.sess_connect++;
+        else
+            s->ctx->stats.sess_connect_renegotiate++;
+
+        /* mark client_random uninitialized */
+        memset(s->s3->client_random, 0, sizeof(s->s3->client_random));
+        s->hit = 0;
+
+        s->s3->tmp.cert_req = 0;
+
+        if (SSL_IS_DTLS(s))
+            s->statem.use_timer = 1;
+    }
+
+    return 1;
+}
+
+/*
+ * Size of the to-be-signed TLS13 data, without the hash size itself:
+ * 64 bytes of value 32, 33 context bytes, 1 byte separator
+ */
+#define TLS13_TBS_START_SIZE            64
+#define TLS13_TBS_PREAMBLE_SIZE         (TLS13_TBS_START_SIZE + 33 + 1)
+
+static int get_cert_verify_tbs_data(SSL *s, unsigned char *tls13tbs,
+                                    void **hdata, size_t *hdatalen)
+{
+    static const char *servercontext = "TLS 1.3, server CertificateVerify";
+    static const char *clientcontext = "TLS 1.3, client CertificateVerify";
+
+    if (SSL_IS_TLS13(s)) {
+        size_t hashlen;
+
+        /* Set the first 64 bytes of to-be-signed data to octet 32 */
+        memset(tls13tbs, 32, TLS13_TBS_START_SIZE);
+        /* This copies the 33 bytes of context plus the 0 separator byte */
+        if (s->statem.hand_state == TLS_ST_CR_CERT_VRFY
+                 || s->statem.hand_state == TLS_ST_SW_CERT_VRFY)
+            strcpy((char *)tls13tbs + TLS13_TBS_START_SIZE, servercontext);
+        else
+            strcpy((char *)tls13tbs + TLS13_TBS_START_SIZE, clientcontext);
+
+        /*
+         * If we're currently reading then we need to use the saved handshake
+         * hash value. We can't use the current handshake hash state because
+         * that includes the CertVerify itself.
+         */
+        if (s->statem.hand_state == TLS_ST_CR_CERT_VRFY
+                || s->statem.hand_state == TLS_ST_SR_CERT_VRFY) {
+            memcpy(tls13tbs + TLS13_TBS_PREAMBLE_SIZE, s->cert_verify_hash,
+                   s->cert_verify_hash_len);
+            hashlen = s->cert_verify_hash_len;
+        } else if (!ssl_handshake_hash(s, tls13tbs + TLS13_TBS_PREAMBLE_SIZE,
+                                       EVP_MAX_MD_SIZE, &hashlen)) {
+            return 0;
+        }
+
+        *hdata = tls13tbs;
+        *hdatalen = TLS13_TBS_PREAMBLE_SIZE + hashlen;
+    } else {
+        size_t retlen;
+
+        retlen = BIO_get_mem_data(s->s3->handshake_buffer, hdata);
+        if (retlen <= 0)
+            return 0;
+        *hdatalen = retlen;
+    }
+
+    return 1;
+}
+
+int tls_construct_cert_verify(SSL *s, WPACKET *pkt)
+{
+    EVP_PKEY *pkey = NULL;
+    const EVP_MD *md = NULL;
+    EVP_MD_CTX *mctx = NULL;
+    EVP_PKEY_CTX *pctx = NULL;
+    size_t hdatalen = 0, siglen = 0;
+    void *hdata;
+    unsigned char *sig = NULL;
+    unsigned char tls13tbs[TLS13_TBS_PREAMBLE_SIZE + EVP_MAX_MD_SIZE];
+    const SIGALG_LOOKUP *lu = s->s3->tmp.sigalg;
+
+    if (lu == NULL || s->s3->tmp.cert == NULL) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+    pkey = s->s3->tmp.cert->privatekey;
+
+    if (pkey == NULL || !tls1_lookup_md(lu, &md)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    mctx = EVP_MD_CTX_new();
+    if (mctx == NULL) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    /* Get the data to be signed */
+    if (!get_cert_verify_tbs_data(s, tls13tbs, &hdata, &hdatalen)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (SSL_USE_SIGALGS(s) && !WPACKET_put_bytes_u16(pkt, lu->sigalg)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+    siglen = EVP_PKEY_size(pkey);
+    sig = OPENSSL_malloc(siglen);
+    if (sig == NULL) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    if (EVP_DigestSignInit(mctx, &pctx, md, NULL, pkey) <= 0) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_EVP_LIB);
+        goto err;
+    }
+
+    if (lu->sig == EVP_PKEY_RSA_PSS) {
+        if (EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) <= 0
+            || EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx,
+                                                RSA_PSS_SALTLEN_DIGEST) <= 0) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_EVP_LIB);
+            goto err;
+        }
+    }
+    if (s->version == SSL3_VERSION) {
+        if (EVP_DigestSignUpdate(mctx, hdata, hdatalen) <= 0
+            || !EVP_MD_CTX_ctrl(mctx, EVP_CTRL_SSL3_MASTER_SECRET,
+                                (int)s->session->master_key_length,
+                                s->session->master_key)
+            || EVP_DigestSignFinal(mctx, sig, &siglen) <= 0) {
+
+            SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_EVP_LIB);
+            goto err;
+        }
+    } else if (EVP_DigestSign(mctx, sig, &siglen, hdata, hdatalen) <= 0) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_EVP_LIB);
+        goto err;
+    }
+
+#ifndef OPENSSL_NO_GOST
+    {
+        int pktype = lu->sig;
+
+        if (pktype == NID_id_GostR3410_2001
+            || pktype == NID_id_GostR3410_2012_256
+            || pktype == NID_id_GostR3410_2012_512)
+            BUF_reverse(sig, NULL, siglen);
+    }
+#endif
+
+    if (!WPACKET_sub_memcpy_u16(pkt, sig, siglen)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    /* Digest cached records and discard handshake buffer */
+    if (!ssl3_digest_cached_records(s, 0))
+        goto err;
+
+    OPENSSL_free(sig);
+    EVP_MD_CTX_free(mctx);
+    return 1;
+ err:
+    OPENSSL_free(sig);
+    EVP_MD_CTX_free(mctx);
+    ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+    return 0;
+}
+
+MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
+{
+    EVP_PKEY *pkey = NULL;
+    const unsigned char *data;
+#ifndef OPENSSL_NO_GOST
+    unsigned char *gost_data = NULL;
+#endif
+    int al = SSL_AD_INTERNAL_ERROR, ret = MSG_PROCESS_ERROR;
+    int type = 0, j;
+    unsigned int len;
+    X509 *peer;
+    const EVP_MD *md = NULL;
+    size_t hdatalen = 0;
+    void *hdata;
+    unsigned char tls13tbs[TLS13_TBS_PREAMBLE_SIZE + EVP_MAX_MD_SIZE];
+    EVP_MD_CTX *mctx = EVP_MD_CTX_new();
+    EVP_PKEY_CTX *pctx = NULL;
+
+    if (mctx == NULL) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto f_err;
+    }
+
+    peer = s->session->peer;
+    pkey = X509_get0_pubkey(peer);
+    if (pkey == NULL)
+        goto f_err;
+
+    type = X509_certificate_type(peer, pkey);
+
+    if (!(type & EVP_PKT_SIGN)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY,
+               SSL_R_SIGNATURE_FOR_NON_SIGNING_CERTIFICATE);
+        al = SSL_AD_ILLEGAL_PARAMETER;
+        goto f_err;
+    }
+
+    if (SSL_USE_SIGALGS(s)) {
+        int rv;
+        unsigned int sigalg;
+
+        if (!PACKET_get_net_2(pkt, &sigalg)) {
+            al = SSL_AD_DECODE_ERROR;
+            goto f_err;
+        }
+        rv = tls12_check_peer_sigalg(s, sigalg, pkey);
+        if (rv == -1) {
+            goto f_err;
+        } else if (rv == 0) {
+            al = SSL_AD_DECODE_ERROR;
+            goto f_err;
+        }
+#ifdef SSL_DEBUG
+        fprintf(stderr, "USING TLSv1.2 HASH %s\n", EVP_MD_name(md));
+#endif
+    } else if (!tls1_set_peer_legacy_sigalg(s, pkey)) {
+            al = SSL_AD_INTERNAL_ERROR;
+            goto f_err;
+    }
+
+    if (!tls1_lookup_md(s->s3->tmp.peer_sigalg, &md)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        al = SSL_AD_INTERNAL_ERROR;
+        goto f_err;
+    }
+
+    /* Check for broken implementations of GOST ciphersuites */
+    /*
+     * If key is GOST and len is exactly 64 or 128, it is signature without
+     * length field (CryptoPro implementations at least till TLS 1.2)
+     */
+#ifndef OPENSSL_NO_GOST
+    if (!SSL_USE_SIGALGS(s)
+        && ((PACKET_remaining(pkt) == 64
+             && (EVP_PKEY_id(pkey) == NID_id_GostR3410_2001
+                 || EVP_PKEY_id(pkey) == NID_id_GostR3410_2012_256))
+            || (PACKET_remaining(pkt) == 128
+                && EVP_PKEY_id(pkey) == NID_id_GostR3410_2012_512))) {
+        len = PACKET_remaining(pkt);
+    } else
+#endif
+    if (!PACKET_get_net_2(pkt, &len)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, SSL_R_LENGTH_MISMATCH);
+        al = SSL_AD_DECODE_ERROR;
+        goto f_err;
+    }
+
+    j = EVP_PKEY_size(pkey);
+    if (((int)len > j) || ((int)PACKET_remaining(pkt) > j)
+        || (PACKET_remaining(pkt) == 0)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, SSL_R_WRONG_SIGNATURE_SIZE);
+        al = SSL_AD_DECODE_ERROR;
+        goto f_err;
+    }
+    if (!PACKET_get_bytes(pkt, &data, len)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, SSL_R_LENGTH_MISMATCH);
+        al = SSL_AD_DECODE_ERROR;
+        goto f_err;
+    }
+
+    if (!get_cert_verify_tbs_data(s, tls13tbs, &hdata, &hdatalen)) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
+        goto f_err;
+    }
+
+#ifdef SSL_DEBUG
+    fprintf(stderr, "Using client verify alg %s\n", EVP_MD_name(md));
+#endif
+    if (EVP_DigestVerifyInit(mctx, &pctx, md, NULL, pkey) <= 0) {
+        SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_EVP_LIB);
+        goto f_err;
+    }
+#ifndef OPENSSL_NO_GOST
+    {
+        int pktype = EVP_PKEY_id(pkey);
+        if (pktype == NID_id_GostR3410_2001
+            || pktype == NID_id_GostR3410_2012_256
+            || pktype == NID_id_GostR3410_2012_512) {
+            if ((gost_data = OPENSSL_malloc(len)) == NULL) {
+                SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_MALLOC_FAILURE);
+                goto f_err;
+            }
+            BUF_reverse(gost_data, data, len);
+            data = gost_data;
+        }
+    }
+#endif
+
+    if (SSL_USE_PSS(s)) {
+        if (EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) <= 0
+            || EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx,
+                                                RSA_PSS_SALTLEN_DIGEST) <= 0) {
+            SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_EVP_LIB);
+            goto f_err;
+        }
+    }
+    if (s->version == SSL3_VERSION) {
+        if (EVP_DigestVerifyUpdate(mctx, hdata, hdatalen) <= 0
+                || !EVP_MD_CTX_ctrl(mctx, EVP_CTRL_SSL3_MASTER_SECRET,
+                                    (int)s->session->master_key_length,
+                                    s->session->master_key)) {
+            SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_EVP_LIB);
+            goto f_err;
+        }
+        if (EVP_DigestVerifyFinal(mctx, data, len) <= 0) {
+            al = SSL_AD_DECRYPT_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, SSL_R_BAD_SIGNATURE);
+            goto f_err;
+        }
+    } else {
+        j = EVP_DigestVerify(mctx, data, len, hdata, hdatalen);
+        if (j < 0) {
+            SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, ERR_R_EVP_LIB);
+            goto f_err;
+        } else if (j == 0) {
+            al = SSL_AD_DECRYPT_ERROR;
+            SSLerr(SSL_F_TLS_PROCESS_CERT_VERIFY, SSL_R_BAD_SIGNATURE);
+            goto f_err;
+        }
+    }
+
+    ret = MSG_PROCESS_CONTINUE_READING;
+    if (0) {
+ f_err:
+        ssl3_send_alert(s, SSL3_AL_FATAL, al);
+        ossl_statem_set_error(s);
+    }
+    BIO_free(s->s3->handshake_buffer);
+    s->s3->handshake_buffer = NULL;
+    EVP_MD_CTX_free(mctx);
+#ifndef OPENSSL_NO_GOST
+    OPENSSL_free(gost_data);
+#endif
+    return ret;
+}
+
 int tls_construct_finished(SSL *s, WPACKET *pkt)
 {
-    int i;
+    size_t finish_md_len;
     const char *sender;
-    int slen;
+    size_t slen;
+
+    /* This is a real handshake so make sure we clean it up at the end */
+    if (!s->server)
+        s->statem.cleanuphand = 1;
+
+    /*
+     * We only change the keys if we didn't already do this when we sent the
+     * client certificate
+     */
+    if (SSL_IS_TLS13(s)
+            && !s->server
+            && s->s3->tmp.cert_req == 0
+            && (!s->method->ssl3_enc->change_cipher_state(s,
+                    SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_CLIENT_WRITE))) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, SSL_R_CANNOT_CHANGE_CIPHER);
+        goto err;
+    }
 
     if (s->server) {
         sender = s->method->ssl3_enc->server_finished_label;
@@ -85,17 +515,28 @@ int tls_construct_finished(SSL *s, WPACKET *pkt)
         slen = s->method->ssl3_enc->client_finished_label_len;
     }
 
-    i = s->method->ssl3_enc->final_finish_mac(s,
-                                              sender, slen,
-                                              s->s3->tmp.finish_md);
-    if (i <= 0) {
+    finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
+                                                          sender, slen,
+                                                          s->s3->tmp.finish_md);
+    if (finish_md_len == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
-    s->s3->tmp.finish_md_len = i;
+    s->s3->tmp.finish_md_len = finish_md_len;
+
+    if (!WPACKET_memcpy(pkt, s->s3->tmp.finish_md, finish_md_len)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
-    if (!WPACKET_memcpy(pkt, s->s3->tmp.finish_md, i)) {
+    /*
+     * Log the master secret, if logging is enabled. We don't log it for
+     * TLSv1.3: there's a different key schedule for that.
+     */
+    if (!SSL_IS_TLS13(s) && !ssl_log_secret(s, MASTER_SECRET_LABEL,
+                                            s->session->master_key,
+                                            s->session->master_key_length)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
         goto err;
     }
@@ -103,22 +544,102 @@ int tls_construct_finished(SSL *s, WPACKET *pkt)
     /*
      * Copy the finished so we can use it for renegotiation checks
      */
+    if (!ossl_assert(finish_md_len <= EVP_MAX_MD_SIZE)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
     if (!s->server) {
-        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
-        memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md, i);
-        s->s3->previous_client_finished_len = i;
+        memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md,
+               finish_md_len);
+        s->s3->previous_client_finished_len = finish_md_len;
     } else {
-        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
-        memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md, i);
-        s->s3->previous_server_finished_len = i;
+        memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md,
+               finish_md_len);
+        s->s3->previous_server_finished_len = finish_md_len;
+    }
+
+    return 1;
+ err:
+    ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
+    return 0;
+}
+
+int tls_construct_key_update(SSL *s, WPACKET *pkt)
+{
+    if (!WPACKET_put_bytes_u8(pkt, s->key_update)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_KEY_UPDATE, ERR_R_INTERNAL_ERROR);
+        goto err;
     }
 
+    s->key_update = SSL_KEY_UPDATE_NONE;
     return 1;
+
  err:
     ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
     return 0;
 }
 
+MSG_PROCESS_RETURN tls_process_key_update(SSL *s, PACKET *pkt)
+{
+    int al;
+    unsigned int updatetype;
+
+    s->key_update_count++;
+    if (s->key_update_count > MAX_KEY_UPDATE_MESSAGES) {
+        al = SSL_AD_ILLEGAL_PARAMETER;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_UPDATE, SSL_R_TOO_MANY_KEY_UPDATES);
+        goto err;
+    }
+
+    /*
+     * A KeyUpdate message signals a key change so the end of the message must
+     * be on a record boundary.
+     */
+    if (RECORD_LAYER_processed_read_pending(&s->rlayer)) {
+        al = SSL_AD_UNEXPECTED_MESSAGE;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_UPDATE, SSL_R_NOT_ON_RECORD_BOUNDARY);
+        goto err;
+    }
+
+    if (!PACKET_get_1(pkt, &updatetype)
+            || PACKET_remaining(pkt) != 0) {
+        al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_UPDATE, SSL_R_BAD_KEY_UPDATE);
+        goto err;
+    }
+
+    /*
+     * There are only two defined key update types. Fail if we get a value we
+     * didn't recognise.
+     */
+    if (updatetype != SSL_KEY_UPDATE_NOT_REQUESTED
+            && updatetype != SSL_KEY_UPDATE_REQUESTED) {
+        al = SSL_AD_ILLEGAL_PARAMETER;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_UPDATE, SSL_R_BAD_KEY_UPDATE);
+        goto err;
+    }
+
+    /*
+     * If we get a request for us to update our sending keys too then, we need
+     * to additionally send a KeyUpdate message. However that message should
+     * not also request an update (otherwise we get into an infinite loop).
+     */
+    if (updatetype == SSL_KEY_UPDATE_REQUESTED)
+        s->key_update = SSL_KEY_UPDATE_NOT_REQUESTED;
+
+    if (!tls13_update_key(s, 0)) {
+        al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_UPDATE, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    return MSG_PROCESS_FINISHED_READING;
+ err:
+    ssl3_send_alert(s, SSL3_AL_FATAL, al);
+    ossl_statem_set_error(s);
+    return MSG_PROCESS_ERROR;
+}
+
 #ifndef OPENSSL_NO_NEXTPROTONEG
 /*
  * ssl3_take_mac calculates the Finished MAC for the handshakes messages seen
@@ -127,7 +648,7 @@ int tls_construct_finished(SSL *s, WPACKET *pkt)
 static void ssl3_take_mac(SSL *s)
 {
     const char *sender;
-    int slen;
+    size_t slen;
     /*
      * If no new cipher setup return immediately: other functions will set
      * the appropriate error.
@@ -152,7 +673,7 @@ static void ssl3_take_mac(SSL *s)
 MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
 {
     int al;
-    long remain;
+    size_t remain;
 
     remain = PACKET_remaining(pkt);
     /*
@@ -165,14 +686,14 @@ MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
              && remain != DTLS1_CCS_HEADER_LENGTH + 1)
             || (s->version != DTLS1_BAD_VER
                 && remain != DTLS1_CCS_HEADER_LENGTH - 1)) {
-            al = SSL_AD_ILLEGAL_PARAMETER;
+            al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
                    SSL_R_BAD_CHANGE_CIPHER_SPEC);
             goto f_err;
         }
     } else {
         if (remain != 0) {
-            al = SSL_AD_ILLEGAL_PARAMETER;
+            al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CHANGE_CIPHER_SPEC,
                    SSL_R_BAD_CHANGE_CIPHER_SPEC);
             goto f_err;
@@ -218,25 +739,42 @@ MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
 
 MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
 {
-    int al, i;
+    int al = SSL_AD_INTERNAL_ERROR;
+    size_t md_len;
+
+
+    /* This is a real handshake so make sure we clean it up at the end */
+    if (s->server)
+        s->statem.cleanuphand = 1;
+
+    /*
+     * In TLSv1.3 a Finished message signals a key change so the end of the
+     * message must be on a record boundary.
+     */
+    if (SSL_IS_TLS13(s) && RECORD_LAYER_processed_read_pending(&s->rlayer)) {
+        al = SSL_AD_UNEXPECTED_MESSAGE;
+        SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_NOT_ON_RECORD_BOUNDARY);
+        goto f_err;
+    }
 
     /* If this occurs, we have missed a message */
-    if (!s->s3->change_cipher_spec) {
+    if (!SSL_IS_TLS13(s) && !s->s3->change_cipher_spec) {
         al = SSL_AD_UNEXPECTED_MESSAGE;
         SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_GOT_A_FIN_BEFORE_A_CCS);
         goto f_err;
     }
     s->s3->change_cipher_spec = 0;
 
-    i = s->s3->tmp.peer_finish_md_len;
+    md_len = s->s3->tmp.peer_finish_md_len;
 
-    if ((unsigned long)i != PACKET_remaining(pkt)) {
+    if (md_len != PACKET_remaining(pkt)) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_BAD_DIGEST_LENGTH);
         goto f_err;
     }
 
-    if (CRYPTO_memcmp(PACKET_data(pkt), s->s3->tmp.peer_finish_md, i) != 0) {
+    if (CRYPTO_memcmp(PACKET_data(pkt), s->s3->tmp.peer_finish_md,
+                      md_len) != 0) {
         al = SSL_AD_DECRYPT_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_DIGEST_CHECK_FAILED);
         goto f_err;
@@ -245,14 +783,47 @@ MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
     /*
      * Copy the finished so we can use it for renegotiation checks
      */
+    if (!ossl_assert(md_len <= EVP_MAX_MD_SIZE)) {
+        al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_FINISHED, ERR_R_INTERNAL_ERROR);
+        goto f_err;
+    }
     if (s->server) {
-        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
-        memcpy(s->s3->previous_client_finished, s->s3->tmp.peer_finish_md, i);
-        s->s3->previous_client_finished_len = i;
+        memcpy(s->s3->previous_client_finished, s->s3->tmp.peer_finish_md,
+               md_len);
+        s->s3->previous_client_finished_len = md_len;
     } else {
-        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
-        memcpy(s->s3->previous_server_finished, s->s3->tmp.peer_finish_md, i);
-        s->s3->previous_server_finished_len = i;
+        memcpy(s->s3->previous_server_finished, s->s3->tmp.peer_finish_md,
+               md_len);
+        s->s3->previous_server_finished_len = md_len;
+    }
+
+    /*
+     * In TLS1.3 we also have to change cipher state and do any final processing
+     * of the initial server flight (if we are a client)
+     */
+    if (SSL_IS_TLS13(s)) {
+        if (s->server) {
+            if (!s->method->ssl3_enc->change_cipher_state(s,
+                    SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_SERVER_READ)) {
+                SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_CANNOT_CHANGE_CIPHER);
+                goto f_err;
+            }
+        } else {
+            if (!s->method->ssl3_enc->generate_master_secret(s,
+                    s->master_secret, s->handshake_secret, 0,
+                    &s->session->master_key_length)) {
+                SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_CANNOT_CHANGE_CIPHER);
+                goto f_err;
+            }
+            if (!s->method->ssl3_enc->change_cipher_state(s,
+                    SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_CLIENT_READ)) {
+                SSLerr(SSL_F_TLS_PROCESS_FINISHED, SSL_R_CANNOT_CHANGE_CIPHER);
+                goto f_err;
+            }
+            if (!tls_process_initial_server_flight(s, &al))
+                goto f_err;
+        }
     }
 
     return MSG_PROCESS_FINISHED_READING;
@@ -273,18 +844,150 @@ int tls_construct_change_cipher_spec(SSL *s, WPACKET *pkt)
     return 1;
 }
 
-unsigned long ssl3_output_cert_chain(SSL *s, WPACKET *pkt, CERT_PKEY *cpk)
+/* Add a certificate to the WPACKET */
+static int ssl_add_cert_to_wpacket(SSL *s, WPACKET *pkt, X509 *x, int chain,
+                                   int *al)
+{
+    int len;
+    unsigned char *outbytes;
+
+    len = i2d_X509(x, NULL);
+    if (len < 0) {
+        SSLerr(SSL_F_SSL_ADD_CERT_TO_WPACKET, ERR_R_BUF_LIB);
+        *al = SSL_AD_INTERNAL_ERROR;
+        return 0;
+    }
+    if (!WPACKET_sub_allocate_bytes_u24(pkt, len, &outbytes)
+            || i2d_X509(x, &outbytes) != len) {
+        SSLerr(SSL_F_SSL_ADD_CERT_TO_WPACKET, ERR_R_INTERNAL_ERROR);
+        *al = SSL_AD_INTERNAL_ERROR;
+        return 0;
+    }
+
+    if (SSL_IS_TLS13(s)
+            && !tls_construct_extensions(s, pkt, SSL_EXT_TLS1_3_CERTIFICATE, x,
+                                         chain, al))
+        return 0;
+
+    return 1;
+}
+
+/* Add certificate chain to provided WPACKET */
+static int ssl_add_cert_chain(SSL *s, WPACKET *pkt, CERT_PKEY *cpk, int *al)
 {
+    int i, chain_count;
+    X509 *x;
+    STACK_OF(X509) *extra_certs;
+    STACK_OF(X509) *chain = NULL;
+    X509_STORE *chain_store;
+    int tmpal = SSL_AD_INTERNAL_ERROR;
+
+    if (cpk == NULL || cpk->x509 == NULL)
+        return 1;
+
+    x = cpk->x509;
+
+    /*
+     * If we have a certificate specific chain use it, else use parent ctx.
+     */
+    if (cpk->chain != NULL)
+        extra_certs = cpk->chain;
+    else
+        extra_certs = s->ctx->extra_certs;
+
+    if ((s->mode & SSL_MODE_NO_AUTO_CHAIN) || extra_certs)
+        chain_store = NULL;
+    else if (s->cert->chain_store)
+        chain_store = s->cert->chain_store;
+    else
+        chain_store = s->ctx->cert_store;
+
+    if (chain_store != NULL) {
+        X509_STORE_CTX *xs_ctx = X509_STORE_CTX_new();
+
+        if (xs_ctx == NULL) {
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, ERR_R_MALLOC_FAILURE);
+            goto err;
+        }
+        if (!X509_STORE_CTX_init(xs_ctx, chain_store, x, NULL)) {
+            X509_STORE_CTX_free(xs_ctx);
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, ERR_R_X509_LIB);
+            goto err;
+        }
+        /*
+         * It is valid for the chain not to be complete (because normally we
+         * don't include the root cert in the chain). Therefore we deliberately
+         * ignore the error return from this call. We're not actually verifying
+         * the cert - we're just building as much of the chain as we can
+         */
+        (void)X509_verify_cert(xs_ctx);
+        /* Don't leave errors in the queue */
+        ERR_clear_error();
+        chain = X509_STORE_CTX_get0_chain(xs_ctx);
+        i = ssl_security_cert_chain(s, chain, NULL, 0);
+        if (i != 1) {
+#if 0
+            /* Dummy error calls so mkerr generates them */
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, SSL_R_EE_KEY_TOO_SMALL);
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, SSL_R_CA_KEY_TOO_SMALL);
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, SSL_R_CA_MD_TOO_WEAK);
+#endif
+            X509_STORE_CTX_free(xs_ctx);
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, i);
+            goto err;
+        }
+        chain_count = sk_X509_num(chain);
+        for (i = 0; i < chain_count; i++) {
+            x = sk_X509_value(chain, i);
+
+            if (!ssl_add_cert_to_wpacket(s, pkt, x, i, &tmpal)) {
+                X509_STORE_CTX_free(xs_ctx);
+                goto err;
+            }
+        }
+        X509_STORE_CTX_free(xs_ctx);
+    } else {
+        i = ssl_security_cert_chain(s, extra_certs, x, 0);
+        if (i != 1) {
+            SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, i);
+            goto err;
+        }
+        if (!ssl_add_cert_to_wpacket(s, pkt, x, 0, &tmpal))
+            goto err;
+        for (i = 0; i < sk_X509_num(extra_certs); i++) {
+            x = sk_X509_value(extra_certs, i);
+            if (!ssl_add_cert_to_wpacket(s, pkt, x, i + 1, &tmpal))
+                goto err;
+        }
+    }
+    return 1;
+
+ err:
+    *al = tmpal;
+    return 0;
+}
+
+unsigned long ssl3_output_cert_chain(SSL *s, WPACKET *pkt, CERT_PKEY *cpk,
+                                     int *al)
+{
+    int tmpal = SSL_AD_INTERNAL_ERROR;
+
     if (!WPACKET_start_sub_packet_u24(pkt)
-            || !ssl_add_cert_chain(s, pkt, cpk)
+            || !ssl_add_cert_chain(s, pkt, cpk, &tmpal)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN, ERR_R_INTERNAL_ERROR);
+        *al = tmpal;
         return 0;
     }
     return 1;
 }
 
-WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst)
+/*
+ * Tidy up after the end of a handshake. In the case of SCTP this may result
+ * in NBIO events. If |clearbufs| is set then init_buf and the wbio buffer is
+ * freed up as well.
+ */
+WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst, int clearbufs)
 {
     void (*cb) (const SSL *ssl, int type, int val) = NULL;
 
@@ -297,26 +1000,27 @@ WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst)
     }
 #endif
 
-    /* clean a few things up */
-    ssl3_cleanup_key_block(s);
-
-    if (!SSL_IS_DTLS(s)) {
-        /*
-         * We don't do this in DTLS because we may still need the init_buf
-         * in case there are any unexpected retransmits
-         */
-        BUF_MEM_free(s->init_buf);
-        s->init_buf = NULL;
+    if (clearbufs) {
+        if (!SSL_IS_DTLS(s)) {
+            /*
+             * We don't do this in DTLS because we may still need the init_buf
+             * in case there are any unexpected retransmits
+             */
+            BUF_MEM_free(s->init_buf);
+            s->init_buf = NULL;
+        }
+        if (!ssl_free_wbio_buffer(s))
+            return WORK_ERROR;
+        s->init_num = 0;
     }
 
-    ssl_free_wbio_buffer(s);
-
-    s->init_num = 0;
-
-    if (!s->server || s->renegotiate == 2) {
+    if (s->statem.cleanuphand) {
         /* skipped if we just sent a HelloRequest */
         s->renegotiate = 0;
         s->new_session = 0;
+        s->statem.cleanuphand = 0;
+
+        ssl3_cleanup_key_block(s);
 
         if (s->server) {
             ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
@@ -349,6 +1053,14 @@ WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst)
         }
     }
 
+    /*
+     * If we've not cleared the buffers its because we've got more work to do,
+     * so continue.
+     */
+    if (!clearbufs)
+        return WORK_FINISHED_CONTINUE;
+
+    ossl_statem_set_in_init(s, 0);
     return WORK_FINISHED_STOP;
 }
 
@@ -357,7 +1069,7 @@ int tls_get_message_header(SSL *s, int *mt)
     /* s->init_num < SSL3_HM_HEADER_LENGTH */
     int skip_message, i, recvd_type, al;
     unsigned char *p;
-    size_t l, read;
+    size_t l, readbytes;
 
     p = (unsigned char *)s->init_buf->data;
 
@@ -366,7 +1078,7 @@ int tls_get_message_header(SSL *s, int *mt)
             i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type,
                                           &p[s->init_num],
                                           SSL3_HM_HEADER_LENGTH - s->init_num,
-                                          0, &read);
+                                          0, &readbytes);
             if (i <= 0) {
                 s->rwstate = SSL_READING;
                 return 0;
@@ -376,27 +1088,29 @@ int tls_get_message_header(SSL *s, int *mt)
                  * A ChangeCipherSpec must be a single byte and may not occur
                  * in the middle of a handshake message.
                  */
-                if (s->init_num != 0 || read != 1 || p[0] != SSL3_MT_CCS) {
+                if (s->init_num != 0 || readbytes != 1 || p[0] != SSL3_MT_CCS) {
                     al = SSL_AD_UNEXPECTED_MESSAGE;
                     SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER,
                            SSL_R_BAD_CHANGE_CIPHER_SPEC);
                     goto f_err;
                 }
                 s->s3->tmp.message_type = *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
-                s->init_num = read - 1;
-                s->s3->tmp.message_size = read;
+                s->init_num = readbytes - 1;
+                s->init_msg = s->init_buf->data;
+                s->s3->tmp.message_size = readbytes;
                 return 1;
             } else if (recvd_type != SSL3_RT_HANDSHAKE) {
                 al = SSL_AD_UNEXPECTED_MESSAGE;
                 SSLerr(SSL_F_TLS_GET_MESSAGE_HEADER, SSL_R_CCS_RECEIVED_EARLY);
                 goto f_err;
             }
-            s->init_num += read;
+            s->init_num += readbytes;
         }
 
         skip_message = 0;
         if (!s->server)
-            if (p[0] == SSL3_MT_HELLO_REQUEST)
+            if (s->statem.hand_state != TLS_ST_OK
+                    && p[0] == SSL3_MT_HELLO_REQUEST)
                 /*
                  * The server may always send 'Hello Request' messages --
                  * we are doing a handshake anyway now, so ignore them if
@@ -454,7 +1168,7 @@ int tls_get_message_header(SSL *s, int *mt)
 
 int tls_get_message_body(SSL *s, size_t *len)
 {
-    size_t n, read;
+    size_t n, readbytes;
     unsigned char *p;
     int i;
 
@@ -468,14 +1182,14 @@ int tls_get_message_body(SSL *s, size_t *len)
     n = s->s3->tmp.message_size - s->init_num;
     while (n > 0) {
         i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL,
-                                      &p[s->init_num], n, 0, &read);
+                                      &p[s->init_num], n, 0, &readbytes);
         if (i <= 0) {
             s->rwstate = SSL_READING;
             *len = 0;
             return 0;
         }
-        s->init_num += read;
-        n -= read;
+        s->init_num += readbytes;
+        n -= readbytes;
     }
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
@@ -500,8 +1214,13 @@ int tls_get_message_body(SSL *s, size_t *len)
             s->msg_callback(0, SSL2_VERSION, 0, s->init_buf->data,
                             (size_t)s->init_num, s, s->msg_callback_arg);
     } else {
-        if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
-                             s->init_num + SSL3_HM_HEADER_LENGTH)) {
+        /*
+         * We defer feeding in the HRR until later. We'll do it as part of
+         * processing the message
+         */
+        if (s->s3->tmp.message_type != SSL3_MT_HELLO_RETRY_REQUEST
+                && !ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
+                                    s->init_num + SSL3_HM_HEADER_LENGTH)) {
             SSLerr(SSL_F_TLS_GET_MESSAGE_BODY, ERR_R_EVP_LIB);
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
             *len = 0;
@@ -526,12 +1245,14 @@ int ssl_cert_type(const X509 *x, const EVP_PKEY *pk)
     default:
         return -1;
     case EVP_PKEY_RSA:
-        return SSL_PKEY_RSA_ENC;
+        return SSL_PKEY_RSA;
     case EVP_PKEY_DSA:
         return SSL_PKEY_DSA_SIGN;
 #ifndef OPENSSL_NO_EC
     case EVP_PKEY_EC:
         return SSL_PKEY_ECC;
+    case NID_ED25519:
+        return SSL_PKEY_ED25519;
 #endif
 #ifndef OPENSSL_NO_GOST
     case NID_id_GostR3410_2001:
@@ -641,6 +1362,7 @@ typedef struct {
 # error Code needs update for TLS_method() support beyond TLS1_3_VERSION.
 #endif
 
+/* Must be in order high to low */
 static const version_info tls_version_table[] = {
 #ifndef OPENSSL_NO_TLS1_3
     {TLS1_3_VERSION, tlsv1_3_client_method, tlsv1_3_server_method},
@@ -674,6 +1396,7 @@ static const version_info tls_version_table[] = {
 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
 #endif
 
+/* Must be in order high to low */
 static const version_info dtls_version_table[] = {
 #ifndef OPENSSL_NO_DTLS1_2
     {DTLS1_2_VERSION, dtlsv1_2_client_method, dtlsv1_2_server_method},
@@ -715,8 +1438,6 @@ static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
         return SSL_R_UNSUPPORTED_PROTOCOL;
     if ((method->flags & SSL_METHOD_NO_SUITEB) != 0 && tls1_suiteb(s))
         return SSL_R_AT_LEAST_TLS_1_2_NEEDED_IN_SUITEB_MODE;
-    else if ((method->flags & SSL_METHOD_NO_FIPS) != 0 && FIPS_mode())
-        return SSL_R_AT_LEAST_TLS_1_0_NEEDED_IN_FIPS_MODE;
 
     return 0;
 }
@@ -858,6 +1579,20 @@ int ssl_set_version_bound(int method_version, int version, int *bound)
     return 1;
 }
 
+static void check_for_downgrade(SSL *s, int vers, DOWNGRADE *dgrd)
+{
+    if (vers == TLS1_2_VERSION
+            && ssl_version_supported(s, TLS1_3_VERSION)) {
+        *dgrd = DOWNGRADE_TO_1_2;
+    } else if (!SSL_IS_DTLS(s) && vers < TLS1_2_VERSION
+            && (ssl_version_supported(s, TLS1_2_VERSION)
+                || ssl_version_supported(s, TLS1_3_VERSION))) {
+        *dgrd = DOWNGRADE_TO_1_1;
+    } else {
+        *dgrd = DOWNGRADE_NONE;
+    }
+}
+
 /*
  * ssl_choose_server_version - Choose server (D)TLS version.  Called when the
  * client HELLO is received to select the final server protocol version and
@@ -867,7 +1602,7 @@ int ssl_set_version_bound(int method_version, int version, int *bound)
  *
  * Returns 0 on success or an SSL error reason number on failure.
  */
-int ssl_choose_server_version(SSL *s)
+int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello, DOWNGRADE *dgrd)
 {
     /*-
      * With version-flexible methods we have an initial state with:
@@ -879,23 +1614,34 @@ int ssl_choose_server_version(SSL *s)
      * handle version.
      */
     int server_version = s->method->version;
-    int client_version = s->client_version;
+    int client_version = hello->legacy_version;
     const version_info *vent;
     const version_info *table;
     int disabled = 0;
+    RAW_EXTENSION *suppversions;
+
+    s->client_version = client_version;
 
     switch (server_version) {
     default:
-        if (version_cmp(s, client_version, s->version) < 0)
-            return SSL_R_WRONG_SSL_VERSION;
+        if (!SSL_IS_TLS13(s)) {
+            if (version_cmp(s, client_version, s->version) < 0)
+                return SSL_R_WRONG_SSL_VERSION;
+            *dgrd = DOWNGRADE_NONE;
+            /*
+             * If this SSL handle is not from a version flexible method we don't
+             * (and never did) check min/max FIPS or Suite B constraints.  Hope
+             * that's OK.  It is up to the caller to not choose fixed protocol
+             * versions they don't want.  If not, then easy to fix, just return
+             * ssl_method_error(s, s->method)
+             */
+            return 0;
+        }
         /*
-         * If this SSL handle is not from a version flexible method we don't
-         * (and never did) check min/max FIPS or Suite B constraints.  Hope
-         * that's OK.  It is up to the caller to not choose fixed protocol
-         * versions they don't want.  If not, then easy to fix, just return
-         * ssl_method_error(s, s->method)
+         * Fall through if we are TLSv1.3 already (this means we must be after
+         * a HelloRetryRequest
          */
-        return 0;
+        /* fall thru */
     case TLS_ANY_VERSION:
         table = tls_version_table;
         break;
@@ -904,6 +1650,80 @@ int ssl_choose_server_version(SSL *s)
         break;
     }
 
+    suppversions = &hello->pre_proc_exts[TLSEXT_IDX_supported_versions];
+
+    if (suppversions->present && !SSL_IS_DTLS(s)) {
+        unsigned int candidate_vers = 0;
+        unsigned int best_vers = 0;
+        const SSL_METHOD *best_method = NULL;
+        PACKET versionslist;
+
+        suppversions->parsed = 1;
+
+        if (!PACKET_as_length_prefixed_1(&suppversions->data, &versionslist)) {
+            /* Trailing or invalid data? */
+            return SSL_R_LENGTH_MISMATCH;
+        }
+
+        while (PACKET_get_net_2(&versionslist, &candidate_vers)) {
+            /* TODO(TLS1.3): Remove this before release */
+            if (candidate_vers == TLS1_3_VERSION_DRAFT)
+                candidate_vers = TLS1_3_VERSION;
+            /*
+             * TODO(TLS1.3): There is some discussion on the TLS list about
+             * whether to ignore versions <TLS1.2 in supported_versions. At the
+             * moment we honour them if present. To be reviewed later
+             */
+            if (version_cmp(s, candidate_vers, best_vers) <= 0)
+                continue;
+            for (vent = table;
+                 vent->version != 0 && vent->version != (int)candidate_vers;
+                 ++vent)
+                continue;
+            if (vent->version != 0 && vent->smeth != NULL) {
+                const SSL_METHOD *method;
+
+                method = vent->smeth();
+                if (ssl_method_error(s, method) == 0) {
+                    best_vers = candidate_vers;
+                    best_method = method;
+                }
+            }
+        }
+        if (PACKET_remaining(&versionslist) != 0) {
+            /* Trailing data? */
+            return SSL_R_LENGTH_MISMATCH;
+        }
+
+        if (best_vers > 0) {
+            if (SSL_IS_TLS13(s)) {
+                /*
+                 * We get here if this is after a HelloRetryRequest. In this
+                 * case we just check that we still negotiated TLSv1.3
+                 */
+                if (best_vers != TLS1_3_VERSION)
+                    return SSL_R_UNSUPPORTED_PROTOCOL;
+                return 0;
+            }
+            check_for_downgrade(s, best_vers, dgrd);
+            s->version = best_vers;
+            s->method = best_method;
+            return 0;
+        }
+        return SSL_R_UNSUPPORTED_PROTOCOL;
+    }
+
+    /*
+     * If the supported versions extension isn't present, then the highest
+     * version we can negotiate is TLSv1.2
+     */
+    if (version_cmp(s, client_version, TLS1_3_VERSION) >= 0)
+        client_version = TLS1_2_VERSION;
+
+    /*
+     * No supported versions extension, so we just use the version supplied in
+     * the ClientHello.
+     */
     for (vent = table; vent->version != 0; ++vent) {
         const SSL_METHOD *method;
 
@@ -912,6 +1732,7 @@ int ssl_choose_server_version(SSL *s)
             continue;
         method = vent->smeth();
         if (ssl_method_error(s, method) == 0) {
+            check_for_downgrade(s, vent->version, dgrd);
             s->version = vent->version;
             s->method = method;
             return 0;
@@ -928,18 +1749,32 @@ int ssl_choose_server_version(SSL *s)
  *
  * @s: client SSL handle.
  * @version: The proposed version from the server's HELLO.
+ * @checkdgrd: Whether to check the downgrade sentinels in the server_random
+ * @al: Where to store any alert value that may be generated
  *
  * Returns 0 on success or an SSL error reason number on failure.
  */
-int ssl_choose_client_version(SSL *s, int version)
+int ssl_choose_client_version(SSL *s, int version, int checkdgrd, int *al)
 {
     const version_info *vent;
     const version_info *table;
+    int highver = 0;
+
+    /* TODO(TLS1.3): Remove this before release */
+    if (version == TLS1_3_VERSION_DRAFT)
+        version = TLS1_3_VERSION;
+
+    if (s->hello_retry_request && version != TLS1_3_VERSION) {
+        *al = SSL_AD_PROTOCOL_VERSION;
+        return SSL_R_WRONG_SSL_VERSION;
+    }
 
     switch (s->method->version) {
     default:
-        if (version != s->version)
+        if (version != s->version) {
+            *al = SSL_AD_PROTOCOL_VERSION;
             return SSL_R_WRONG_SSL_VERSION;
+        }
         /*
          * If this SSL handle is not from a version flexible method we don't
          * (and never did) check min/max, FIPS or Suite B constraints.  Hope
@@ -960,24 +1795,64 @@ int ssl_choose_client_version(SSL *s, int version)
         const SSL_METHOD *method;
         int err;
 
-        if (version != vent->version)
-            continue;
         if (vent->cmeth == NULL)
-            break;
+            continue;
+
+        if (highver != 0 && version != vent->version)
+            continue;
+
         method = vent->cmeth();
         err = ssl_method_error(s, method);
-        if (err != 0)
-            return err;
+        if (err != 0) {
+            if (version == vent->version) {
+                *al = SSL_AD_PROTOCOL_VERSION;
+                return err;
+            }
+
+            continue;
+        }
+        if (highver == 0)
+            highver = vent->version;
+
+        if (version != vent->version)
+            continue;
+
+#ifndef OPENSSL_NO_TLS13DOWNGRADE
+        /* Check for downgrades */
+        if (checkdgrd) {
+            if (version == TLS1_2_VERSION && highver > version) {
+                if (memcmp(tls12downgrade,
+                           s->s3->server_random + SSL3_RANDOM_SIZE
+                                                - sizeof(tls12downgrade),
+                           sizeof(tls12downgrade)) == 0) {
+                    *al = SSL_AD_ILLEGAL_PARAMETER;
+                    return SSL_R_INAPPROPRIATE_FALLBACK;
+                }
+            } else if (!SSL_IS_DTLS(s)
+                       && version < TLS1_2_VERSION
+                       && highver > version) {
+                if (memcmp(tls11downgrade,
+                           s->s3->server_random + SSL3_RANDOM_SIZE
+                                                - sizeof(tls11downgrade),
+                           sizeof(tls11downgrade)) == 0) {
+                    *al = SSL_AD_ILLEGAL_PARAMETER;
+                    return SSL_R_INAPPROPRIATE_FALLBACK;
+                }
+            }
+        }
+#endif
+
         s->method = method;
         s->version = version;
         return 0;
     }
 
+    *al = SSL_AD_PROTOCOL_VERSION;
     return SSL_R_UNSUPPORTED_PROTOCOL;
 }
 
 /*
- * ssl_get_client_min_max_version - get minimum and maximum client version
+ * ssl_get_min_max_version - get minimum and maximum protocol version
  * @s: The SSL connection
  * @min_version: The minimum supported version
  * @max_version: The maximum supported version
@@ -985,7 +1860,7 @@ int ssl_choose_client_version(SSL *s, int version)
  * Work out what version we should be using for the initial ClientHello if the
  * version is initially (D)TLS_ANY_VERSION.  We apply any explicit SSL_OP_NO_xxx
  * options, the MinProtocol and MaxProtocol configuration commands, any Suite B
- * or FIPS_mode() constraints and any floor imposed by the security level here,
+ * constraints and any floor imposed by the security level here,
  * so we don't advertise the wrong protocol version to only reject the outcome later.
  *
  * Computing the right floor matters.  If, e.g., TLS 1.0 and 1.2 are enabled,
@@ -995,8 +1870,7 @@ int ssl_choose_client_version(SSL *s, int version)
  * Returns 0 on success or an SSL error reason number on failure.  On failure
  * min_version and max_version will also be set to 0.
  */
-int ssl_get_client_min_max_version(const SSL *s, int *min_version,
-                                   int *max_version)
+int ssl_get_min_max_version(const SSL *s, int *min_version, int *max_version)
 {
     int version;
     int hole;
@@ -1080,7 +1954,7 @@ int ssl_get_client_min_max_version(const SSL *s, int *min_version,
 
 /*
  * ssl_set_client_hello_version - Work out what version we should be using for
- * the initial ClientHello.
+ * the initial ClientHello.legacy_version field.
  *
  * @s: client SSL handle.
  *
@@ -1090,11 +1964,189 @@ int ssl_set_client_hello_version(SSL *s)
 {
     int ver_min, ver_max, ret;
 
-    ret = ssl_get_client_min_max_version(s, &ver_min, &ver_max);
+    ret = ssl_get_min_max_version(s, &ver_min, &ver_max);
 
     if (ret != 0)
         return ret;
 
-    s->client_version = s->version = ver_max;
+    s->version = ver_max;
+
+    /* TLS1.3 always uses TLS1.2 in the legacy_version field */
+    if (!SSL_IS_DTLS(s) && ver_max > TLS1_2_VERSION)
+        ver_max = TLS1_2_VERSION;
+
+    s->client_version = ver_max;
+    return 0;
+}
+
+/*
+ * Checks a list of |groups| to determine if the |group_id| is in it. If it is
+ * and |checkallow| is 1 then additionally check if the group is allowed to be
+ * used. Returns 1 if the group is in the list (and allowed if |checkallow| is
+ * 1) or 0 otherwise.
+ */
+#ifndef OPENSSL_NO_EC
+int check_in_list(SSL *s, unsigned int group_id, const unsigned char *groups,
+                  size_t num_groups, int checkallow)
+{
+    size_t i;
+
+    if (groups == NULL || num_groups == 0)
+        return 0;
+
+    for (i = 0; i < num_groups; i++, groups += 2) {
+        if (group_id == GET_GROUP_ID(groups, 0)
+                && (!checkallow
+                    || tls_curve_allowed(s, groups, SSL_SECOP_CURVE_CHECK))) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+#endif
+
+/* Replace ClientHello1 in the transcript hash with a synthetic message */
+int create_synthetic_message_hash(SSL *s)
+{
+    unsigned char hashval[EVP_MAX_MD_SIZE];
+    size_t hashlen = 0;
+    unsigned char msghdr[SSL3_HM_HEADER_LENGTH];
+
+    memset(msghdr, 0, sizeof(msghdr));
+
+    /* Get the hash of the initial ClientHello */
+    if (!ssl3_digest_cached_records(s, 0)
+            || !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
+        SSLerr(SSL_F_CREATE_SYNTHETIC_MESSAGE_HASH, ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    /* Reinitialise the transcript hash */
+    if (!ssl3_init_finished_mac(s))
+        return 0;
+
+    /* Inject the synthetic message_hash message */
+    msghdr[0] = SSL3_MT_MESSAGE_HASH;
+    msghdr[SSL3_HM_HEADER_LENGTH - 1] = hashlen;
+    if (!ssl3_finish_mac(s, msghdr, SSL3_HM_HEADER_LENGTH)
+            || !ssl3_finish_mac(s, hashval, hashlen)) {
+        SSLerr(SSL_F_CREATE_SYNTHETIC_MESSAGE_HASH, ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    return 1;
+}
+
+static int ca_dn_cmp(const X509_NAME *const *a, const X509_NAME *const *b)
+{
+    return X509_NAME_cmp(*a, *b);
+}
+
+int parse_ca_names(SSL *s, PACKET *pkt, int *al)
+{
+    STACK_OF(X509_NAME) *ca_sk = sk_X509_NAME_new(ca_dn_cmp);
+    X509_NAME *xn = NULL;
+    PACKET cadns;
+
+    if (ca_sk == NULL) {
+        SSLerr(SSL_F_PARSE_CA_NAMES, ERR_R_MALLOC_FAILURE);
+        goto decerr;
+    }
+    /* get the CA RDNs */
+    if (!PACKET_get_length_prefixed_2(pkt, &cadns)) {
+        *al = SSL_AD_DECODE_ERROR;
+        SSLerr(SSL_F_PARSE_CA_NAMES, SSL_R_LENGTH_MISMATCH);
+        goto decerr;
+    }
+
+    while (PACKET_remaining(&cadns)) {
+        const unsigned char *namestart, *namebytes;
+        unsigned int name_len;
+
+        if (!PACKET_get_net_2(&cadns, &name_len)
+            || !PACKET_get_bytes(&cadns, &namebytes, name_len)) {
+            SSLerr(SSL_F_PARSE_CA_NAMES, SSL_R_LENGTH_MISMATCH);
+            goto decerr;
+        }
+
+        namestart = namebytes;
+        if ((xn = d2i_X509_NAME(NULL, &namebytes, name_len)) == NULL) {
+            SSLerr(SSL_F_PARSE_CA_NAMES, ERR_R_ASN1_LIB);
+            goto decerr;
+        }
+        if (namebytes != (namestart + name_len)) {
+            SSLerr(SSL_F_PARSE_CA_NAMES, SSL_R_CA_DN_LENGTH_MISMATCH);
+            goto decerr;
+        }
+
+        if (!sk_X509_NAME_push(ca_sk, xn)) {
+            SSLerr(SSL_F_PARSE_CA_NAMES, ERR_R_MALLOC_FAILURE);
+            *al = SSL_AD_INTERNAL_ERROR;
+            goto err;
+        }
+        xn = NULL;
+    }
+
+    sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
+    s->s3->tmp.peer_ca_names = ca_sk;
+
+    return 1;
+
+ decerr:
+    *al = SSL_AD_DECODE_ERROR;
+ err:
+    sk_X509_NAME_pop_free(ca_sk, X509_NAME_free);
+    X509_NAME_free(xn);
     return 0;
 }
+
+int construct_ca_names(SSL *s, WPACKET *pkt)
+{
+    const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
+
+    /* Start sub-packet for client CA list */
+    if (!WPACKET_start_sub_packet_u16(pkt))
+        return 0;
+
+    if (ca_sk != NULL) {
+        int i;
+
+        for (i = 0; i < sk_X509_NAME_num(ca_sk); i++) {
+            unsigned char *namebytes;
+            X509_NAME *name = sk_X509_NAME_value(ca_sk, i);
+            int namelen;
+
+            if (name == NULL
+                    || (namelen = i2d_X509_NAME(name, NULL)) < 0
+                    || !WPACKET_sub_allocate_bytes_u16(pkt, namelen,
+                                                       &namebytes)
+                    || i2d_X509_NAME(name, &namebytes) != namelen) {
+                return 0;
+            }
+        }
+    }
+
+    if (!WPACKET_close(pkt))
+        return 0;
+
+    return 1;
+}
+
+/* Create a buffer containing data to be signed for server key exchange */
+size_t construct_key_exchange_tbs(const SSL *s, unsigned char **ptbs,
+                                  const void *param, size_t paramlen)
+{
+    size_t tbslen = 2 * SSL3_RANDOM_SIZE + paramlen;
+    unsigned char *tbs = OPENSSL_malloc(tbslen);
+
+    if (tbs == NULL)
+        return 0;
+    memcpy(tbs, s->s3->client_random, SSL3_RANDOM_SIZE);
+    memcpy(tbs + SSL3_RANDOM_SIZE, s->s3->server_random, SSL3_RANDOM_SIZE);
+
+    memcpy(tbs + SSL3_RANDOM_SIZE * 2, param, paramlen);
+
+    *ptbs = tbs;
+    return tbslen;
+}