Revert "Keep the DTLS timer running after the end of the handshake if appropriate"
[openssl.git] / ssl / statem / statem_lib.c
index d64ddff..2f78a3f 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2018 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
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
 #include <openssl/evp.h>
 #include <openssl/x509.h>
 
+/*
+ * Map error codes to TLS/SSL alart types.
+ */
+typedef struct x509err2alert_st {
+    int x509err;
+    int alert;
+} X509ERR2ALERT;
+
 /* Fixed value used in the ServerHello random field to identify an HRR */
 const unsigned char hrrrandom[] = {
     0xcf, 0x21, 0xad, 0x74, 0xe5, 0x9a, 0x61, 0x11, 0xbe, 0x1d, 0x8c, 0x02,
@@ -43,12 +51,15 @@ int ssl3_do_write(SSL *s, int type)
         /*
          * should not be done for 'Hello Request's, but in that case we'll
          * ignore the result anyway
+         * TLS1.3 KeyUpdate and NewSessionTicket do not need to be added
          */
-        if (!ssl3_finish_mac(s,
-                             (unsigned char *)&s->init_buf->data[s->init_off],
-                             written))
-            return -1;
-
+        if (!SSL_IS_TLS13(s) || (s->statem.hand_state != TLS_ST_SW_SESSION_TICKET
+                                 && s->statem.hand_state != TLS_ST_CW_KEY_UPDATE
+                                 && s->statem.hand_state != TLS_ST_SW_KEY_UPDATE))
+            if (!ssl3_finish_mac(s,
+                                 (unsigned char *)&s->init_buf->data[s->init_off],
+                                 written))
+                return -1;
     if (written == s->init_num) {
         if (s->msg_callback)
             s->msg_callback(1, s->version, type, s->init_buf->data,
@@ -94,7 +105,7 @@ int tls_setup_handshake(SSL *s)
          * enabled. For clients we do this check during construction of the
          * ClientHello.
          */
-        if (ssl_get_min_max_version(s, &ver_min, &ver_max) != 0) {
+        if (ssl_get_min_max_version(s, &ver_min, &ver_max, NULL) != 0) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_SETUP_HANDSHAKE,
                      ERR_R_INTERNAL_ERROR);
             return 0;
@@ -121,37 +132,18 @@ int tls_setup_handshake(SSL *s)
         }
         if (SSL_IS_FIRST_HANDSHAKE(s)) {
             /* N.B. s->session_ctx == s->ctx here */
-            CRYPTO_atomic_add(&s->session_ctx->stats.sess_accept, 1, &i,
-                              s->session_ctx->lock);
-        } 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.
-             */
-            SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_SETUP_HANDSHAKE,
-                     SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
-            return 0;
+            tsan_counter(&s->session_ctx->stats.sess_accept);
         } else {
             /* N.B. s->ctx may not equal s->session_ctx */
-            CRYPTO_atomic_add(&s->ctx->stats.sess_accept_renegotiate, 1, &i,
-                              s->ctx->lock);
+            tsan_counter(&s->ctx->stats.sess_accept_renegotiate);
 
             s->s3->tmp.cert_request = 0;
         }
     } else {
-        int discard;
         if (SSL_IS_FIRST_HANDSHAKE(s))
-            CRYPTO_atomic_add(&s->session_ctx->stats.sess_connect, 1, &discard,
-                              s->session_ctx->lock);
+            tsan_counter(&s->session_ctx->stats.sess_connect);
         else
-            CRYPTO_atomic_add(&s->session_ctx->stats.sess_connect_renegotiate,
-                              1, &discard, s->session_ctx->lock);
+            tsan_counter(&s->session_ctx->stats.sess_connect_renegotiate);
 
         /* mark client_random uninitialized */
         memset(s->s3->client_random, 0, sizeof(s->s3->client_random));
@@ -211,9 +203,10 @@ static int get_cert_verify_tbs_data(SSL *s, unsigned char *tls13tbs,
         *hdatalen = TLS13_TBS_PREAMBLE_SIZE + hashlen;
     } else {
         size_t retlen;
+        long retlen_l;
 
-        retlen = BIO_get_mem_data(s->s3->handshake_buffer, hdata);
-        if (retlen <= 0) {
+        retlen = retlen_l = BIO_get_mem_data(s->s3->handshake_buffer, hdata);
+        if (retlen_l <= 0) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_GET_CERT_VERIFY_TBS_DATA,
                      ERR_R_INTERNAL_ERROR);
             return 0;
@@ -389,9 +382,6 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
             /* SSLfatal() already called */
             goto 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)) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CERT_VERIFY,
                      ERR_R_INTERNAL_ERROR);
@@ -404,6 +394,12 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
         goto err;
     }
 
+#ifdef SSL_DEBUG
+    if (SSL_USE_SIGALGS(s))
+        fprintf(stderr, "USING TLSv1.2 HASH %s\n",
+                md == NULL ? "n/a" : EVP_MD_name(md));
+#endif
+
     /* Check for broken implementations of GOST ciphersuites */
     /*
      * If key is GOST and len is exactly 64 or 128, it is signature without
@@ -444,7 +440,8 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
     }
 
 #ifdef SSL_DEBUG
-    fprintf(stderr, "Using client verify alg %s\n", EVP_MD_name(md));
+    fprintf(stderr, "Using client verify alg %s\n",
+            md == NULL ? "n/a" : EVP_MD_name(md));
 #endif
     if (EVP_DigestVerifyInit(mctx, &pctx, md, NULL, pkey) <= 0) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CERT_VERIFY,
@@ -500,7 +497,18 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL *s, PACKET *pkt)
         }
     }
 
-    ret = MSG_PROCESS_CONTINUE_READING;
+    /*
+     * In TLSv1.3 on the client side we make sure we prepare the client
+     * certificate after the CertVerify instead of when we get the
+     * CertificateRequest. This is because in TLSv1.3 the CertificateRequest
+     * comes *before* the Certificate message. In TLSv1.2 it comes after. We
+     * want to make sure that SSL_get_peer_certificate() will return the actual
+     * server certificate from the client_cert_cb callback.
+     */
+    if (!s->server && SSL_IS_TLS13(s) && s->s3->tmp.cert_req == 1)
+        ret = MSG_PROCESS_CONTINUE_PROCESSING;
+    else
+        ret = MSG_PROCESS_CONTINUE_READING;
  err:
     BIO_free(s->s3->handshake_buffer);
     s->s3->handshake_buffer = NULL;
@@ -518,7 +526,7 @@ int tls_construct_finished(SSL *s, WPACKET *pkt)
     size_t slen;
 
     /* This is a real handshake so make sure we clean it up at the end */
-    if (!s->server)
+    if (!s->server && s->post_handshake_auth != SSL_PHA_REQUESTED)
         s->statem.cleanuphand = 1;
 
     /*
@@ -644,9 +652,12 @@ MSG_PROCESS_RETURN tls_process_key_update(SSL *s, PACKET *pkt)
     /*
      * 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).
+     * not also request an update (otherwise we get into an infinite loop). We
+     * ignore a request for us to update our sending keys too if we already
+     * sent close_notify.
      */
-    if (updatetype == SSL_KEY_UPDATE_REQUESTED)
+    if (updatetype == SSL_KEY_UPDATE_REQUESTED
+            && (s->shutdown & SSL_SENT_SHUTDOWN) == 0)
         s->key_update = SSL_KEY_UPDATE_NOT_REQUESTED;
 
     if (!tls13_update_key(s, 0)) {
@@ -657,21 +668,15 @@ MSG_PROCESS_RETURN tls_process_key_update(SSL *s, PACKET *pkt)
     return MSG_PROCESS_FINISHED_READING;
 }
 
-#ifndef OPENSSL_NO_NEXTPROTONEG
 /*
  * ssl3_take_mac calculates the Finished MAC for the handshakes messages seen
  * to far.
  */
-static void ssl3_take_mac(SSL *s)
+int ssl3_take_mac(SSL *s)
 {
     const char *sender;
     size_t slen;
-    /*
-     * If no new cipher setup return immediately: other functions will set
-     * the appropriate error.
-     */
-    if (s->s3->tmp.new_cipher == NULL)
-        return;
+
     if (!s->server) {
         sender = s->method->ssl3_enc->server_finished_label;
         slen = s->method->ssl3_enc->server_finished_label_len;
@@ -680,12 +685,17 @@ static void ssl3_take_mac(SSL *s)
         slen = s->method->ssl3_enc->client_finished_label_len;
     }
 
-    s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
-                                                                          sender,
-                                                                          slen,
-                                                                          s->s3->tmp.peer_finish_md);
+    s->s3->tmp.peer_finish_md_len =
+        s->method->ssl3_enc->final_finish_mac(s, sender, slen,
+                                              s->s3->tmp.peer_finish_md);
+
+    if (s->s3->tmp.peer_finish_md_len == 0) {
+        /* SSLfatal() already called */
+        return 0;
+    }
+
+    return 1;
 }
-#endif
 
 MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL *s, PACKET *pkt)
 {
@@ -755,8 +765,20 @@ MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
 
 
     /* This is a real handshake so make sure we clean it up at the end */
-    if (s->server)
-        s->statem.cleanuphand = 1;
+    if (s->server) {
+        /*
+        * To get this far we must have read encrypted data from the client. We
+        * no longer tolerate unencrypted alerts. This value is ignored if less
+        * than TLSv1.3
+        */
+        s->statem.enc_read_state = ENC_READ_STATE_VALID;
+        if (s->post_handshake_auth != SSL_PHA_REQUESTED)
+            s->statem.cleanuphand = 1;
+        if (SSL_IS_TLS13(s) && !tls13_save_handshake_digest_for_pha(s)) {
+                /* SSLfatal() already called */
+                return MSG_PROCESS_ERROR;
+        }
+    }
 
     /*
      * In TLSv1.3 a Finished message signals a key change so the end of the
@@ -815,7 +837,8 @@ MSG_PROCESS_RETURN tls_process_finished(SSL *s, PACKET *pkt)
      */
     if (SSL_IS_TLS13(s)) {
         if (s->server) {
-            if (!s->method->ssl3_enc->change_cipher_state(s,
+            if (s->post_handshake_auth != SSL_PHA_REQUESTED &&
+                    !s->method->ssl3_enc->change_cipher_state(s,
                     SSL3_CC_APPLICATION | SSL3_CHANGE_CIPHER_SERVER_READ)) {
                 /* SSLfatal() already called */
                 return MSG_PROCESS_ERROR;
@@ -1004,20 +1027,10 @@ unsigned long ssl3_output_cert_chain(SSL *s, WPACKET *pkt, CERT_PKEY *cpk)
  * 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)
+WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst, int clearbufs, int stop)
 {
-    int discard;
     void (*cb) (const SSL *ssl, int type, int val) = NULL;
 
-#ifndef OPENSSL_NO_SCTP
-    if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
-        WORK_STATE ret;
-        ret = dtls_wait_for_dry(s);
-        if (ret != WORK_FINISHED_CONTINUE)
-            return ret;
-    }
-#endif
-
     if (clearbufs) {
         if (!SSL_IS_DTLS(s)) {
             /*
@@ -1035,45 +1048,57 @@ WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst, int clearbufs)
         s->init_num = 0;
     }
 
+    if (SSL_IS_TLS13(s) && !s->server
+            && s->post_handshake_auth == SSL_PHA_REQUESTED)
+        s->post_handshake_auth = SSL_PHA_EXT_SENT;
+
+    /*
+     * Only set if there was a Finished message and this isn't after a TLSv1.3
+     * post handshake exchange
+     */
     if (s->statem.cleanuphand) {
         /* skipped if we just sent a HelloRequest */
         s->renegotiate = 0;
         s->new_session = 0;
         s->statem.cleanuphand = 0;
+        s->ext.ticket_expected = 0;
 
         ssl3_cleanup_key_block(s);
 
         if (s->server) {
-            ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
-
-            /* N.B. s->ctx may not equal s->session_ctx */
-            CRYPTO_atomic_add(&s->ctx->stats.sess_accept_good, 1, &discard,
-                              s->ctx->lock);
-            s->handshake_func = ossl_statem_accept;
-        } else {
             /*
-             * In TLSv1.3 we update the cache as part of processing the
+             * In TLSv1.3 we update the cache as part of constructing the
              * NewSessionTicket
              */
             if (!SSL_IS_TLS13(s))
+                ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
+
+            /* N.B. s->ctx may not equal s->session_ctx */
+            tsan_counter(&s->ctx->stats.sess_accept_good);
+            s->handshake_func = ossl_statem_accept;
+        } else {
+            if (SSL_IS_TLS13(s)) {
+                /*
+                 * We encourage applications to only use TLSv1.3 tickets once,
+                 * so we remove this one from the cache.
+                 */
+                if ((s->session_ctx->session_cache_mode
+                     & SSL_SESS_CACHE_CLIENT) != 0)
+                    SSL_CTX_remove_session(s->session_ctx, s->session);
+            } else {
+                /*
+                 * In TLSv1.3 we update the cache as part of processing the
+                 * NewSessionTicket
+                 */
                 ssl_update_cache(s, SSL_SESS_CACHE_CLIENT);
+            }
             if (s->hit)
-                CRYPTO_atomic_add(&s->session_ctx->stats.sess_hit, 1, &discard,
-                                  s->session_ctx->lock);
+                tsan_counter(&s->session_ctx->stats.sess_hit);
 
             s->handshake_func = ossl_statem_connect;
-            CRYPTO_atomic_add(&s->session_ctx->stats.sess_connect_good, 1,
-                              &discard, s->session_ctx->lock);
+            tsan_counter(&s->session_ctx->stats.sess_connect_good);
         }
 
-        if (s->info_callback != NULL)
-            cb = s->info_callback;
-        else if (s->ctx->info_callback != NULL)
-            cb = s->ctx->info_callback;
-
-        if (cb != NULL)
-            cb(s, SSL_CB_HANDSHAKE_DONE, 1);
-
         if (SSL_IS_DTLS(s)) {
             /* done with handshaking */
             s->d1->handshake_read_seq = 0;
@@ -1083,14 +1108,23 @@ WORK_STATE tls_finish_handshake(SSL *s, WORK_STATE wst, int clearbufs)
         }
     }
 
-    /*
-     * If we've not cleared the buffers its because we've got more work to do,
-     * so continue.
-     */
-    if (!clearbufs)
-        return WORK_FINISHED_CONTINUE;
+    if (s->info_callback != NULL)
+        cb = s->info_callback;
+    else if (s->ctx->info_callback != NULL)
+        cb = s->ctx->info_callback;
 
+    /* The callback may expect us to not be in init at handshake done */
     ossl_statem_set_in_init(s, 0);
+
+    if (cb != NULL)
+        cb(s, SSL_CB_HANDSHAKE_DONE, 1);
+
+    if (!stop) {
+        /* If we've got more work to do we go back into init */
+        ossl_statem_set_in_init(s, 1);
+        return WORK_FINISHED_CONTINUE;
+    }
+
     return WORK_FINISHED_STOP;
 }
 
@@ -1124,6 +1158,17 @@ int tls_get_message_header(SSL *s, int *mt)
                              SSL_R_BAD_CHANGE_CIPHER_SPEC);
                     return 0;
                 }
+                if (s->statem.hand_state == TLS_ST_BEFORE
+                        && (s->s3->flags & TLS1_FLAGS_STATELESS) != 0) {
+                    /*
+                     * We are stateless and we received a CCS. Probably this is
+                     * from a client between the first and second ClientHellos.
+                     * We should ignore this, but return an error because we do
+                     * not return success until we see the second ClientHello
+                     * with a valid cookie.
+                     */
+                    return 0;
+                }
                 s->s3->tmp.message_type = *mt = SSL3_MT_CHANGE_CIPHER_SPEC;
                 s->init_num = readbytes - 1;
                 s->init_msg = s->init_buf->data;
@@ -1220,14 +1265,15 @@ int tls_get_message_body(SSL *s, size_t *len)
         n -= readbytes;
     }
 
-#ifndef OPENSSL_NO_NEXTPROTONEG
     /*
      * If receiving Finished, record MAC of prior handshake messages for
      * Finished verification.
      */
-    if (*s->init_buf->data == SSL3_MT_FINISHED)
-        ssl3_take_mac(s);
-#endif
+    if (*(s->init_buf->data) == SSL3_MT_FINISHED && !ssl3_take_mac(s)) {
+        /* SSLfatal() already called */
+        *len = 0;
+        return 0;
+    }
 
     /* Feed this message into MAC computation. */
     if (RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
@@ -1244,18 +1290,24 @@ int tls_get_message_body(SSL *s, size_t *len)
         /*
          * We defer feeding in the HRR until later. We'll do it as part of
          * processing the message
+         * The TLsv1.3 handshake transcript stops at the ClientFinished
+         * message.
          */
 #define SERVER_HELLO_RANDOM_OFFSET  (SSL3_HM_HEADER_LENGTH + 2)
-        if (s->s3->tmp.message_type != SSL3_MT_SERVER_HELLO
-                || s->init_num < SERVER_HELLO_RANDOM_OFFSET + SSL3_RANDOM_SIZE
-                || memcmp(hrrrandom,
-                          s->init_buf->data + SERVER_HELLO_RANDOM_OFFSET,
-                          SSL3_RANDOM_SIZE) != 0) {
-            if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
-                                 s->init_num + SSL3_HM_HEADER_LENGTH)) {
-                /* SSLfatal() already called */
-                *len = 0;
-                return 0;
+        /* KeyUpdate and NewSessionTicket do not need to be added */
+        if (!SSL_IS_TLS13(s) || (s->s3->tmp.message_type != SSL3_MT_NEWSESSION_TICKET
+                                 && s->s3->tmp.message_type != SSL3_MT_KEY_UPDATE)) {
+            if (s->s3->tmp.message_type != SSL3_MT_SERVER_HELLO
+                    || s->init_num < SERVER_HELLO_RANDOM_OFFSET + SSL3_RANDOM_SIZE
+                    || memcmp(hrrrandom,
+                              s->init_buf->data + SERVER_HELLO_RANDOM_OFFSET,
+                              SSL3_RANDOM_SIZE) != 0) {
+                if (!ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
+                                     s->init_num + SSL3_HM_HEADER_LENGTH)) {
+                    /* SSLfatal() already called */
+                    *len = 0;
+                    return 0;
+                }
             }
         }
         if (s->msg_callback)
@@ -1268,73 +1320,59 @@ int tls_get_message_body(SSL *s, size_t *len)
     return 1;
 }
 
-int ssl_verify_alarm_type(long type)
+static const X509ERR2ALERT x509table[] = {
+    {X509_V_ERR_APPLICATION_VERIFICATION, SSL_AD_HANDSHAKE_FAILURE},
+    {X509_V_ERR_CA_KEY_TOO_SMALL, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CA_MD_TOO_WEAK, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CERT_CHAIN_TOO_LONG, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_CERT_HAS_EXPIRED, SSL_AD_CERTIFICATE_EXPIRED},
+    {X509_V_ERR_CERT_NOT_YET_VALID, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CERT_REJECTED, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CERT_REVOKED, SSL_AD_CERTIFICATE_REVOKED},
+    {X509_V_ERR_CERT_SIGNATURE_FAILURE, SSL_AD_DECRYPT_ERROR},
+    {X509_V_ERR_CERT_UNTRUSTED, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CRL_HAS_EXPIRED, SSL_AD_CERTIFICATE_EXPIRED},
+    {X509_V_ERR_CRL_NOT_YET_VALID, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_CRL_SIGNATURE_FAILURE, SSL_AD_DECRYPT_ERROR},
+    {X509_V_ERR_DANE_NO_MATCH, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_EE_KEY_TOO_SMALL, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_EMAIL_MISMATCH, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_HOSTNAME_MISMATCH, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_INVALID_CA, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_INVALID_CALL, SSL_AD_INTERNAL_ERROR},
+    {X509_V_ERR_INVALID_PURPOSE, SSL_AD_UNSUPPORTED_CERTIFICATE},
+    {X509_V_ERR_IP_ADDRESS_MISMATCH, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_OUT_OF_MEM, SSL_AD_INTERNAL_ERROR},
+    {X509_V_ERR_PATH_LENGTH_EXCEEDED, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_STORE_LOOKUP, SSL_AD_INTERNAL_ERROR},
+    {X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE, SSL_AD_BAD_CERTIFICATE},
+    {X509_V_ERR_UNABLE_TO_GET_CRL, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE, SSL_AD_UNKNOWN_CA},
+    {X509_V_ERR_UNSPECIFIED, SSL_AD_INTERNAL_ERROR},
+
+    /* Last entry; return this if we don't find the value above. */
+    {X509_V_OK, SSL_AD_CERTIFICATE_UNKNOWN}
+};
+
+int ssl_x509err2alert(int x509err)
 {
-    int al;
+    const X509ERR2ALERT *tp;
 
-    switch (type) {
-    case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
-    case X509_V_ERR_UNABLE_TO_GET_CRL:
-    case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
-        al = SSL_AD_UNKNOWN_CA;
-        break;
-    case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
-    case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
-    case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
-    case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
-    case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
-    case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
-    case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
-    case X509_V_ERR_CERT_NOT_YET_VALID:
-    case X509_V_ERR_CRL_NOT_YET_VALID:
-    case X509_V_ERR_CERT_UNTRUSTED:
-    case X509_V_ERR_CERT_REJECTED:
-    case X509_V_ERR_HOSTNAME_MISMATCH:
-    case X509_V_ERR_EMAIL_MISMATCH:
-    case X509_V_ERR_IP_ADDRESS_MISMATCH:
-    case X509_V_ERR_DANE_NO_MATCH:
-    case X509_V_ERR_EE_KEY_TOO_SMALL:
-    case X509_V_ERR_CA_KEY_TOO_SMALL:
-    case X509_V_ERR_CA_MD_TOO_WEAK:
-        al = SSL_AD_BAD_CERTIFICATE;
-        break;
-    case X509_V_ERR_CERT_SIGNATURE_FAILURE:
-    case X509_V_ERR_CRL_SIGNATURE_FAILURE:
-        al = SSL_AD_DECRYPT_ERROR;
-        break;
-    case X509_V_ERR_CERT_HAS_EXPIRED:
-    case X509_V_ERR_CRL_HAS_EXPIRED:
-        al = SSL_AD_CERTIFICATE_EXPIRED;
-        break;
-    case X509_V_ERR_CERT_REVOKED:
-        al = SSL_AD_CERTIFICATE_REVOKED;
-        break;
-    case X509_V_ERR_UNSPECIFIED:
-    case X509_V_ERR_OUT_OF_MEM:
-    case X509_V_ERR_INVALID_CALL:
-    case X509_V_ERR_STORE_LOOKUP:
-        al = SSL_AD_INTERNAL_ERROR;
-        break;
-    case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
-    case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
-    case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
-    case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
-    case X509_V_ERR_CERT_CHAIN_TOO_LONG:
-    case X509_V_ERR_PATH_LENGTH_EXCEEDED:
-    case X509_V_ERR_INVALID_CA:
-        al = SSL_AD_UNKNOWN_CA;
-        break;
-    case X509_V_ERR_APPLICATION_VERIFICATION:
-        al = SSL_AD_HANDSHAKE_FAILURE;
-        break;
-    case X509_V_ERR_INVALID_PURPOSE:
-        al = SSL_AD_UNSUPPORTED_CERTIFICATE;
-        break;
-    default:
-        al = SSL_AD_CERTIFICATE_UNKNOWN;
-        break;
-    }
-    return al;
+    for (tp = x509table; tp->x509err != X509_V_OK; ++tp)
+        if (tp->x509err == x509err)
+            break;
+    return tp->alert;
 }
 
 int ssl_allow_compression(SSL *s)
@@ -1361,7 +1399,7 @@ typedef struct {
     const SSL_METHOD *(*smeth) (void);
 } version_info;
 
-#if TLS_MAX_VERSION != TLS1_3_VERSION
+#if TLS_MAX_VERSION_INTERNAL != TLS1_3_VERSION
 # error Code needs update for TLS_method() support beyond TLS1_3_VERSION.
 #endif
 
@@ -1395,7 +1433,7 @@ static const version_info tls_version_table[] = {
     {0, NULL, NULL},
 };
 
-#if DTLS_MAX_VERSION != DTLS1_2_VERSION
+#if DTLS_MAX_VERSION_INTERNAL != DTLS1_2_VERSION
 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
 #endif
 
@@ -1445,6 +1483,62 @@ static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
     return 0;
 }
 
+/*
+ * Only called by servers. Returns 1 if the server has a TLSv1.3 capable
+ * certificate type, or has PSK or a certificate callback configured. Otherwise
+ * returns 0.
+ */
+static int is_tls13_capable(const SSL *s)
+{
+    int i;
+#ifndef OPENSSL_NO_EC
+    int curve;
+    EC_KEY *eckey;
+#endif
+
+#ifndef OPENSSL_NO_PSK
+    if (s->psk_server_callback != NULL)
+        return 1;
+#endif
+
+    if (s->psk_find_session_cb != NULL || s->cert->cert_cb != NULL)
+        return 1;
+
+    for (i = 0; i < SSL_PKEY_NUM; i++) {
+        /* Skip over certs disallowed for TLSv1.3 */
+        switch (i) {
+        case SSL_PKEY_DSA_SIGN:
+        case SSL_PKEY_GOST01:
+        case SSL_PKEY_GOST12_256:
+        case SSL_PKEY_GOST12_512:
+            continue;
+        default:
+            break;
+        }
+        if (!ssl_has_cert(s, i))
+            continue;
+#ifndef OPENSSL_NO_EC
+        if (i != SSL_PKEY_ECC)
+            return 1;
+        /*
+         * Prior to TLSv1.3 sig algs allowed any curve to be used. TLSv1.3 is
+         * more restrictive so check that our sig algs are consistent with this
+         * EC cert. See section 4.2.3 of RFC8446.
+         */
+        eckey = EVP_PKEY_get0_EC_KEY(s->cert->pkeys[SSL_PKEY_ECC].privatekey);
+        if (eckey == NULL)
+            continue;
+        curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(eckey));
+        if (tls_check_sigalg_curve(s, curve))
+            return 1;
+#else
+        return 1;
+#endif
+    }
+
+    return 0;
+}
+
 /*
  * ssl_version_supported - Check that the specified `version` is supported by
  * `SSL *` instance
@@ -1454,7 +1548,7 @@ static int ssl_method_error(const SSL *s, const SSL_METHOD *method)
  *
  * Returns 1 when supported, otherwise 0
  */
-int ssl_version_supported(const SSL *s, int version)
+int ssl_version_supported(const SSL *s, int version, const SSL_METHOD **meth)
 {
     const version_info *vent;
     const version_info *table;
@@ -1474,9 +1568,14 @@ int ssl_version_supported(const SSL *s, int version)
     for (vent = table;
          vent->version != 0 && version_cmp(s, version, vent->version) <= 0;
          ++vent) {
-        if (vent->cmeth != NULL &&
-            version_cmp(s, version, vent->version) == 0 &&
-            ssl_method_error(s, vent->cmeth()) == 0) {
+        if (vent->cmeth != NULL
+                && version_cmp(s, version, vent->version) == 0
+                && ssl_method_error(s, vent->cmeth()) == 0
+                && (!s->server
+                    || version != TLS1_3_VERSION
+                    || is_tls13_capable(s))) {
+            if (meth != NULL)
+                *meth = vent->cmeth();
             return 1;
         }
     }
@@ -1567,12 +1666,12 @@ int ssl_set_version_bound(int method_version, int version, int *bound)
         return 0;
 
     case TLS_ANY_VERSION:
-        if (version < SSL3_VERSION || version > TLS_MAX_VERSION)
+        if (version < SSL3_VERSION || version > TLS_MAX_VERSION_INTERNAL)
             return 0;
         break;
 
     case DTLS_ANY_VERSION:
-        if (DTLS_VERSION_GT(version, DTLS_MAX_VERSION) ||
+        if (DTLS_VERSION_GT(version, DTLS_MAX_VERSION_INTERNAL) ||
             DTLS_VERSION_LT(version, DTLS1_BAD_VER))
             return 0;
         break;
@@ -1585,11 +1684,18 @@ int ssl_set_version_bound(int method_version, int version, int *bound)
 static void check_for_downgrade(SSL *s, int vers, DOWNGRADE *dgrd)
 {
     if (vers == TLS1_2_VERSION
-            && ssl_version_supported(s, TLS1_3_VERSION)) {
+            && ssl_version_supported(s, TLS1_3_VERSION, NULL)) {
         *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))) {
+    } else if (!SSL_IS_DTLS(s)
+            && vers < TLS1_2_VERSION
+               /*
+                * We need to ensure that a server that disables TLSv1.2
+                * (creating a hole between TLSv1.3 and TLSv1.1) can still
+                * complete handshakes with clients that support TLSv1.2 and
+                * below. Therefore we do not enable the sentinel if TLSv1.3 is
+                * enabled and TLSv1.2 is not.
+                */
+            && ssl_version_supported(s, TLS1_2_VERSION, NULL)) {
         *dgrd = DOWNGRADE_TO_1_1;
     } else {
         *dgrd = DOWNGRADE_NONE;
@@ -1611,7 +1717,7 @@ int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello, DOWNGRADE *dgrd)
      * With version-flexible methods we have an initial state with:
      *
      *   s->method->version == (D)TLS_ANY_VERSION,
-     *   s->version == (D)TLS_MAX_VERSION.
+     *   s->version == (D)TLS_MAX_VERSION_INTERNAL.
      *
      * So we detect version-flexible methods via the method version, not the
      * handle version.
@@ -1656,7 +1762,7 @@ int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello, DOWNGRADE *dgrd)
     suppversions = &hello->pre_proc_exts[TLSEXT_IDX_supported_versions];
 
     /* If we did an HRR then supported versions is mandatory */
-    if (!suppversions->present && s->hello_retry_request)
+    if (!suppversions->present && s->hello_retry_request != SSL_HRR_NONE)
         return SSL_R_UNSUPPORTED_PROTOCOL;
 
     if (suppversions->present && !SSL_IS_DTLS(s)) {
@@ -1672,30 +1778,23 @@ int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello, DOWNGRADE *dgrd)
             return SSL_R_LENGTH_MISMATCH;
         }
 
+        /*
+         * The TLSv1.3 spec says the client MUST set this to TLS1_2_VERSION.
+         * The spec only requires servers to check that it isn't SSLv3:
+         * "Any endpoint receiving a Hello message with
+         * ClientHello.legacy_version or ServerHello.legacy_version set to
+         * 0x0300 MUST abort the handshake with a "protocol_version" alert."
+         * We are slightly stricter and require that it isn't SSLv3 or lower.
+         * We tolerate TLSv1 and TLSv1.1.
+         */
+        if (client_version <= SSL3_VERSION)
+            return SSL_R_BAD_LEGACY_VERSION;
+
         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 (ssl_version_supported(s, candidate_vers, &best_method))
+                best_vers = candidate_vers;
         }
         if (PACKET_remaining(&versionslist) != 0) {
             /* Trailing data? */
@@ -1703,7 +1802,7 @@ int ssl_choose_server_version(SSL *s, CLIENTHELLO_MSG *hello, DOWNGRADE *dgrd)
         }
 
         if (best_vers > 0) {
-            if (s->hello_retry_request) {
+            if (s->hello_retry_request != SSL_HRR_NONE) {
                 /*
                  * This is after a HelloRetryRequest so we better check that we
                  * negotiated TLSv1.3
@@ -1764,8 +1863,7 @@ int ssl_choose_client_version(SSL *s, int version, RAW_EXTENSION *extensions)
 {
     const version_info *vent;
     const version_info *table;
-    int highver = 0;
-    int origv;
+    int ret, ver_min, ver_max, real_max, origv;
 
     origv = s->version;
     s->version = version;
@@ -1779,7 +1877,8 @@ int ssl_choose_client_version(SSL *s, int version, RAW_EXTENSION *extensions)
         return 0;
     }
 
-    if (s->hello_retry_request && s->version != TLS1_3_VERSION) {
+    if (s->hello_retry_request != SSL_HRR_NONE
+            && s->version != TLS1_3_VERSION) {
         s->version = origv;
         SSLfatal(s, SSL_AD_PROTOCOL_VERSION, SSL_F_SSL_CHOOSE_CLIENT_VERSION,
                  SSL_R_WRONG_SSL_VERSION);
@@ -1811,64 +1910,62 @@ int ssl_choose_client_version(SSL *s, int version, RAW_EXTENSION *extensions)
         break;
     }
 
-    for (vent = table; vent->version != 0; ++vent) {
-        const SSL_METHOD *method;
-        int err;
-
-        if (vent->cmeth == NULL)
-            continue;
-
-        if (highver != 0 && s->version != vent->version)
-            continue;
+    ret = ssl_get_min_max_version(s, &ver_min, &ver_max, &real_max);
+    if (ret != 0) {
+        s->version = origv;
+        SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
+                 SSL_F_SSL_CHOOSE_CLIENT_VERSION, ret);
+        return 0;
+    }
+    if (SSL_IS_DTLS(s) ? DTLS_VERSION_LT(s->version, ver_min)
+                       : s->version < ver_min) {
+        s->version = origv;
+        SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
+                 SSL_F_SSL_CHOOSE_CLIENT_VERSION, SSL_R_UNSUPPORTED_PROTOCOL);
+        return 0;
+    } else if (SSL_IS_DTLS(s) ? DTLS_VERSION_GT(s->version, ver_max)
+                              : s->version > ver_max) {
+        s->version = origv;
+        SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
+                 SSL_F_SSL_CHOOSE_CLIENT_VERSION, SSL_R_UNSUPPORTED_PROTOCOL);
+        return 0;
+    }
 
-        method = vent->cmeth();
-        err = ssl_method_error(s, method);
-        if (err != 0) {
-            if (s->version == vent->version) {
-                s->version = origv;
-                SSLfatal(s, SSL_AD_PROTOCOL_VERSION,
-                         SSL_F_SSL_CHOOSE_CLIENT_VERSION, err);
-                return 0;
-            }
+    if ((s->mode & SSL_MODE_SEND_FALLBACK_SCSV) == 0)
+        real_max = ver_max;
 
-            continue;
+    /* Check for downgrades */
+    if (s->version == TLS1_2_VERSION && real_max > s->version) {
+        if (memcmp(tls12downgrade,
+                   s->s3->server_random + SSL3_RANDOM_SIZE
+                                        - sizeof(tls12downgrade),
+                   sizeof(tls12downgrade)) == 0) {
+            s->version = origv;
+            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                     SSL_F_SSL_CHOOSE_CLIENT_VERSION,
+                     SSL_R_INAPPROPRIATE_FALLBACK);
+            return 0;
         }
-        if (highver == 0)
-            highver = vent->version;
+    } else if (!SSL_IS_DTLS(s)
+               && s->version < TLS1_2_VERSION
+               && real_max > s->version) {
+        if (memcmp(tls11downgrade,
+                   s->s3->server_random + SSL3_RANDOM_SIZE
+                                        - sizeof(tls11downgrade),
+                   sizeof(tls11downgrade)) == 0) {
+            s->version = origv;
+            SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
+                     SSL_F_SSL_CHOOSE_CLIENT_VERSION,
+                     SSL_R_INAPPROPRIATE_FALLBACK);
+            return 0;
+        }
+    }
 
-        if (s->version != vent->version)
+    for (vent = table; vent->version != 0; ++vent) {
+        if (vent->cmeth == NULL || s->version != vent->version)
             continue;
 
-#ifndef OPENSSL_NO_TLS13DOWNGRADE
-        /* Check for downgrades */
-        if (s->version == TLS1_2_VERSION && highver > s->version) {
-            if (memcmp(tls12downgrade,
-                       s->s3->server_random + SSL3_RANDOM_SIZE
-                                            - sizeof(tls12downgrade),
-                       sizeof(tls12downgrade)) == 0) {
-                s->version = origv;
-                SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
-                         SSL_F_SSL_CHOOSE_CLIENT_VERSION,
-                         SSL_R_INAPPROPRIATE_FALLBACK);
-                return 0;
-            }
-        } else if (!SSL_IS_DTLS(s)
-                   && s->version < TLS1_2_VERSION
-                   && highver > s->version) {
-            if (memcmp(tls11downgrade,
-                       s->s3->server_random + SSL3_RANDOM_SIZE
-                                            - sizeof(tls11downgrade),
-                       sizeof(tls11downgrade)) == 0) {
-                s->version = origv;
-                SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
-                         SSL_F_SSL_CHOOSE_CLIENT_VERSION,
-                         SSL_R_INAPPROPRIATE_FALLBACK);
-                return 0;
-            }
-        }
-#endif
-
-        s->method = method;
+        s->method = vent->cmeth();
         return 1;
     }
 
@@ -1883,6 +1980,9 @@ int ssl_choose_client_version(SSL *s, int version, RAW_EXTENSION *extensions)
  * @s: The SSL connection
  * @min_version: The minimum supported version
  * @max_version: The maximum supported version
+ * @real_max:    The highest version below the lowest compile time version hole
+ *               where that hole lies above at least one run-time enabled
+ *               protocol.
  *
  * 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
@@ -1897,9 +1997,10 @@ int ssl_choose_client_version(SSL *s, int version, RAW_EXTENSION *extensions)
  * 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_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 *real_max)
 {
-    int version;
+    int version, tmp_real_max;
     int hole;
     const SSL_METHOD *single = NULL;
     const SSL_METHOD *method;
@@ -1916,6 +2017,12 @@ int ssl_get_min_max_version(const SSL *s, int *min_version, int *max_version)
          * ssl_method_error(s, s->method)
          */
         *min_version = *max_version = s->version;
+        /*
+         * Providing a real_max only makes sense where we're using a version
+         * flexible method.
+         */
+        if (!ossl_assert(real_max == NULL))
+            return ERR_R_INTERNAL_ERROR;
         return 0;
     case TLS_ANY_VERSION:
         table = tls_version_table;
@@ -1948,6 +2055,9 @@ int ssl_get_min_max_version(const SSL *s, int *min_version, int *max_version)
      */
     *min_version = version = 0;
     hole = 1;
+    if (real_max != NULL)
+        *real_max = 0;
+    tmp_real_max = 0;
     for (vent = table; vent->version != 0; ++vent) {
         /*
          * A table entry with a NULL client method is still a hole in the
@@ -1955,15 +2065,22 @@ int ssl_get_min_max_version(const SSL *s, int *min_version, int *max_version)
          */
         if (vent->cmeth == NULL) {
             hole = 1;
+            tmp_real_max = 0;
             continue;
         }
         method = vent->cmeth();
+
+        if (hole == 1 && tmp_real_max == 0)
+            tmp_real_max = vent->version;
+
         if (ssl_method_error(s, method) != 0) {
             hole = 1;
         } else if (!hole) {
             single = NULL;
             *min_version = method->version;
         } else {
+            if (real_max != NULL && tmp_real_max != 0)
+                *real_max = tmp_real_max;
             version = (single = method)->version;
             *min_version = version;
             hole = 0;
@@ -1991,7 +2108,14 @@ int ssl_set_client_hello_version(SSL *s)
 {
     int ver_min, ver_max, ret;
 
-    ret = ssl_get_min_max_version(s, &ver_min, &ver_max);
+    /*
+     * In a renegotiation we always send the same client_version that we sent
+     * last time, regardless of which version we eventually negotiated.
+     */
+    if (!SSL_IS_FIRST_HANDSHAKE(s))
+        return 0;
+
+    ret = ssl_get_min_max_version(s, &ver_min, &ver_max, NULL);
 
     if (ret != 0)
         return ret;
@@ -2036,19 +2160,25 @@ int check_in_list(SSL *s, uint16_t group_id, const uint16_t *groups,
 #endif
 
 /* Replace ClientHello1 in the transcript hash with a synthetic message */
-int create_synthetic_message_hash(SSL *s)
+int create_synthetic_message_hash(SSL *s, const unsigned char *hashval,
+                                  size_t hashlen, const unsigned char *hrr,
+                                  size_t hrrlen)
 {
-    unsigned char hashval[EVP_MAX_MD_SIZE];
-    size_t hashlen = 0;
+    unsigned char hashvaltmp[EVP_MAX_MD_SIZE];
     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)) {
-        /* SSLfatal() already called */
-        return 0;
+    if (hashval == NULL) {
+        hashval = hashvaltmp;
+        hashlen = 0;
+        /* Get the hash of the initial ClientHello */
+        if (!ssl3_digest_cached_records(s, 0)
+                || !ssl_handshake_hash(s, hashvaltmp, sizeof(hashvaltmp),
+                                       &hashlen)) {
+            /* SSLfatal() already called */
+            return 0;
+        }
     }
 
     /* Reinitialise the transcript hash */
@@ -2066,6 +2196,20 @@ int create_synthetic_message_hash(SSL *s)
         return 0;
     }
 
+    /*
+     * Now re-inject the HRR and current message if appropriate (we just deleted
+     * it when we reinitialised the transcript hash above). Only necessary after
+     * receiving a ClientHello2 with a cookie.
+     */
+    if (hrr != NULL
+            && (!ssl3_finish_mac(s, hrr, hrrlen)
+                || !ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,
+                                    s->s3->tmp.message_size
+                                    + SSL3_HM_HEADER_LENGTH))) {
+        /* SSLfatal() already called */
+        return 0;
+    }
+
     return 1;
 }
 
@@ -2134,10 +2278,24 @@ int parse_ca_names(SSL *s, PACKET *pkt)
     return 0;
 }
 
-int construct_ca_names(SSL *s, WPACKET *pkt)
+const STACK_OF(X509_NAME) *get_ca_names(SSL *s)
 {
-    const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
+    const STACK_OF(X509_NAME) *ca_sk = NULL;;
+
+    if (s->server) {
+        ca_sk = SSL_get_client_CA_list(s);
+        if (ca_sk != NULL && sk_X509_NAME_num(ca_sk) == 0)
+            ca_sk = NULL;
+    }
+
+    if (ca_sk == NULL)
+        ca_sk = SSL_get0_CA_list(s);
 
+    return ca_sk;
+}
+
+int construct_ca_names(SSL *s, const STACK_OF(X509_NAME) *ca_sk, WPACKET *pkt)
+{
     /* Start sub-packet for client CA list */
     if (!WPACKET_start_sub_packet_u16(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_CONSTRUCT_CA_NAMES,
@@ -2194,3 +2352,54 @@ size_t construct_key_exchange_tbs(SSL *s, unsigned char **ptbs,
     *ptbs = tbs;
     return tbslen;
 }
+
+/*
+ * Saves the current handshake digest for Post-Handshake Auth,
+ * Done after ClientFinished is processed, done exactly once
+ */
+int tls13_save_handshake_digest_for_pha(SSL *s)
+{
+    if (s->pha_dgst == NULL) {
+        if (!ssl3_digest_cached_records(s, 1))
+            /* SSLfatal() already called */
+            return 0;
+
+        s->pha_dgst = EVP_MD_CTX_new();
+        if (s->pha_dgst == NULL) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS13_SAVE_HANDSHAKE_DIGEST_FOR_PHA,
+                     ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+        if (!EVP_MD_CTX_copy_ex(s->pha_dgst,
+                                s->s3->handshake_dgst)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                     SSL_F_TLS13_SAVE_HANDSHAKE_DIGEST_FOR_PHA,
+                     ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+    }
+    return 1;
+}
+
+/*
+ * Restores the Post-Handshake Auth handshake digest
+ * Done just before sending/processing the Cert Request
+ */
+int tls13_restore_handshake_digest_for_pha(SSL *s)
+{
+    if (s->pha_dgst == NULL) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS13_RESTORE_HANDSHAKE_DIGEST_FOR_PHA,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+    if (!EVP_MD_CTX_copy_ex(s->s3->handshake_dgst,
+                            s->pha_dgst)) {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_F_TLS13_RESTORE_HANDSHAKE_DIGEST_FOR_PHA,
+                 ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+    return 1;
+}