Move the extensions context codes into the public API
[oweals/openssl.git] / ssl / statem / extensions.c
index fd050f0d2ebfc12ec4ef7c8d0e15d9a0ef64f1d3..c2e0411240669704d38864e9b5a116976dbc14e8 100644 (file)
@@ -7,6 +7,7 @@
  * https://www.openssl.org/source/license.html
  */
 
+#include <string.h>
 #include "../ssl_locl.h"
 #include "statem_locl.h"
 
@@ -29,6 +30,13 @@ static int init_npn(SSL *s, unsigned int context);
 static int init_alpn(SSL *s, unsigned int context);
 static int final_alpn(SSL *s, unsigned int context, int sent, int *al);
 static int init_sig_algs(SSL *s, unsigned int context);
+static int init_certificate_authorities(SSL *s, unsigned int context);
+static int tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
+                                                 unsigned int context, X509 *x,
+                                                 size_t chainidx, int *al);
+static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al);
 #ifndef OPENSSL_NO_SRP
 static int init_srp(SSL *s, unsigned int context);
 #endif
@@ -36,11 +44,14 @@ static int init_etm(SSL *s, unsigned int context);
 static int init_ems(SSL *s, unsigned int context);
 static int final_ems(SSL *s, unsigned int context, int sent, int *al);
 static int init_psk_kex_modes(SSL *s, unsigned int context);
+#ifndef OPENSSL_NO_EC
 static int final_key_share(SSL *s, unsigned int context, int sent, int *al);
+#endif
 #ifndef OPENSSL_NO_SRTP
 static int init_srtp(SSL *s, unsigned int context);
 #endif
 static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al);
+static int final_early_data(SSL *s, unsigned int context, int sent, int *al);
 
 /* Structure to define a built-in extension */
 typedef struct extensions_definition_st {
@@ -103,16 +114,16 @@ typedef struct extensions_definition_st {
 static const EXTENSION_DEFINITION ext_defs[] = {
     {
         TLSEXT_TYPE_renegotiate,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_SSL3_ALLOWED
-        | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate,
         tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate,
         final_renegotiate
     },
     {
         TLSEXT_TYPE_server_name,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         init_server_name,
         tls_parse_ctos_server_name, tls_parse_stoc_server_name,
         tls_construct_stoc_server_name, tls_construct_ctos_server_name,
@@ -121,7 +132,7 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #ifndef OPENSSL_NO_SRP
     {
         TLSEXT_TYPE_srp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL
     },
 #else
@@ -130,14 +141,15 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #ifndef OPENSSL_NO_EC
     {
         TLSEXT_TYPE_ec_point_formats,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats,
         tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats,
         final_ec_pt_formats
     },
     {
         TLSEXT_TYPE_supported_groups,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         NULL, tls_parse_ctos_supported_groups, NULL,
         NULL /* TODO(TLS1.3): Need to add this */,
         tls_construct_ctos_supported_groups, NULL
@@ -148,22 +160,24 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_session_ticket,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_session_ticket, tls_parse_ctos_session_ticket,
         tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket,
         tls_construct_ctos_session_ticket, NULL
     },
     {
         TLSEXT_TYPE_signature_algorithms,
-        EXT_CLIENT_HELLO,
-        init_sig_algs, tls_parse_ctos_sig_algs, NULL, NULL,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST,
+        init_sig_algs, tls_parse_ctos_sig_algs,
+        tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs,
         tls_construct_ctos_sig_algs, final_sig_algs
     },
 #ifndef OPENSSL_NO_OCSP
     {
         TLSEXT_TYPE_status_request,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_CERTIFICATE,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_CERTIFICATE,
         init_status_request, tls_parse_ctos_status_request,
         tls_parse_stoc_status_request, tls_construct_stoc_status_request,
         tls_construct_ctos_status_request, NULL
@@ -174,7 +188,8 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #ifndef OPENSSL_NO_NEXTPROTONEG
     {
         TLSEXT_TYPE_next_proto_neg,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn,
         tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL
     },
@@ -187,16 +202,16 @@ static const EXTENSION_DEFINITION ext_defs[] = {
          * happens after server_name callbacks
          */
         TLSEXT_TYPE_application_layer_protocol_negotiation,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
         init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn,
         tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn
     },
 #ifndef OPENSSL_NO_SRTP
     {
         TLSEXT_TYPE_use_srtp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_ENCRYPTED_EXTENSIONS | EXT_DTLS_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY,
         init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp,
         tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL
     },
@@ -205,15 +220,16 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_encrypt_then_mac,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm,
         tls_construct_stoc_etm, tls_construct_ctos_etm, NULL
     },
 #ifndef OPENSSL_NO_CT
     {
         TLSEXT_TYPE_signed_certificate_timestamp,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO
-        | EXT_TLS1_3_CERTIFICATE,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_3_CERTIFICATE,
         NULL,
         /*
          * No server side support for this, but can be provided by a custom
@@ -227,50 +243,78 @@ static const EXTENSION_DEFINITION ext_defs[] = {
 #endif
     {
         TLSEXT_TYPE_extended_master_secret,
-        EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems,
         tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems
     },
     {
         TLSEXT_TYPE_supported_versions,
-        EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         NULL,
         /* Processed inline as part of version selection */
         NULL, NULL, NULL, tls_construct_ctos_supported_versions, NULL
     },
     {
         TLSEXT_TYPE_psk_kex_modes,
-        EXT_CLIENT_HELLO | EXT_TLS_IMPLEMENTATION_ONLY | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL,
         tls_construct_ctos_psk_kex_modes, NULL
     },
+#ifndef OPENSSL_NO_EC
     {
         /*
          * Must be in this list after supported_groups. We need that to have
          * been parsed before we do this one.
          */
         TLSEXT_TYPE_key_share,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO
-        | EXT_TLS1_3_HELLO_RETRY_REQUEST | EXT_TLS_IMPLEMENTATION_ONLY
-        | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
+        | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY
+        | SSL_EXT_TLS1_3_ONLY,
         NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share,
         tls_construct_stoc_key_share, tls_construct_ctos_key_share,
         final_key_share
     },
+#endif
+    {
+        TLSEXT_TYPE_cookie,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST
+        | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
+        NULL, NULL, tls_parse_stoc_cookie, NULL, tls_construct_ctos_cookie,
+        NULL
+    },
     {
         /*
          * Special unsolicited ServerHello extension only used when
          * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
          */
         TLSEXT_TYPE_cryptopro_bug,
-        EXT_TLS1_2_SERVER_HELLO | EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
     },
+    {
+        TLSEXT_TYPE_early_data,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS
+        | SSL_EXT_TLS1_3_NEW_SESSION_TICKET,
+        NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data,
+        tls_construct_stoc_early_data, tls_construct_ctos_early_data,
+        final_early_data
+    },
+    {
+        TLSEXT_TYPE_certificate_authorities,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST
+        | SSL_EXT_TLS1_3_ONLY,
+        init_certificate_authorities,
+        tls_parse_certificate_authorities, tls_parse_certificate_authorities,
+        tls_construct_certificate_authorities,
+        tls_construct_certificate_authorities, NULL,
+    },
     {
         /* Must be immediately before pre_shared_key */
-        /* TODO(TLS1.3): Fix me */
         TLSEXT_TYPE_padding,
-        EXT_CLIENT_HELLO,
+        SSL_EXT_CLIENT_HELLO,
         NULL,
         /* We send this, but don't read it */
         NULL, NULL, NULL, tls_construct_ctos_padding, NULL
@@ -278,8 +322,8 @@ static const EXTENSION_DEFINITION ext_defs[] = {
     {
         /* Required by the TLSv1.3 spec to always be the last extension */
         TLSEXT_TYPE_psk,
-        EXT_CLIENT_HELLO | EXT_TLS1_3_SERVER_HELLO | EXT_TLS_IMPLEMENTATION_ONLY
-        | EXT_TLS1_3_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO
+        | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY,
         NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk,
         tls_construct_ctos_psk, NULL
     }
@@ -289,7 +333,7 @@ static const EXTENSION_DEFINITION ext_defs[] = {
  * Verify whether we are allowed to use the extension |type| in the current
  * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to
  * indicate the extension is not allowed. If returning 1 then |*found| is set to
- * 1 if we found a definition for the extension, and |*idx| is set to its index
+ * the definition for the extension we found.
  */
 static int verify_extension(SSL *s, unsigned int context, unsigned int type,
                             custom_ext_methods *meths, RAW_EXTENSION *rawexlist,
@@ -306,9 +350,9 @@ static int verify_extension(SSL *s, unsigned int context, unsigned int type,
                 return 0;
 
             if (SSL_IS_DTLS(s)) {
-                if ((thisext->context & EXT_TLS_ONLY) != 0)
+                if ((thisext->context & SSL_EXT_TLS_ONLY) != 0)
                     return 0;
-            } else if ((thisext->context & EXT_DTLS_ONLY) != 0) {
+            } else if ((thisext->context & SSL_EXT_DTLS_ONLY) != 0) {
                     return 0;
             }
 
@@ -317,7 +361,7 @@ static int verify_extension(SSL *s, unsigned int context, unsigned int type,
         }
     }
 
-    if ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) == 0) {
+    if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) == 0) {
         /*
          * Custom extensions only apply to <=TLS1.2. This extension is unknown
          * in this context - we allow it
@@ -350,12 +394,12 @@ static int extension_is_relevant(SSL *s, unsigned int extctx,
                                  unsigned int thisctx)
 {
     if ((SSL_IS_DTLS(s)
-                && (extctx & EXT_TLS_IMPLEMENTATION_ONLY) != 0)
+                && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0)
             || (s->version == SSL3_VERSION
-                    && (extctx & EXT_SSL3_ALLOWED) == 0)
+                    && (extctx & SSL_EXT_SSL3_ALLOWED) == 0)
             || (SSL_IS_TLS13(s)
-                && (extctx & EXT_TLS1_2_AND_BELOW_ONLY) != 0)
-            || (!SSL_IS_TLS13(s) && (extctx & EXT_TLS1_3_ONLY) != 0))
+                && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0)
+            || (!SSL_IS_TLS13(s) && (extctx & SSL_EXT_TLS1_3_ONLY) != 0))
         return 0;
 
     return 1;
@@ -378,10 +422,11 @@ static int extension_is_relevant(SSL *s, unsigned int extctx,
  * extensions that we know about. We ignore others.
  */
 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
-                           RAW_EXTENSION **res, int *al)
+                           RAW_EXTENSION **res, int *al, size_t *len)
 {
     PACKET extensions = *packet;
     size_t i = 0;
+    size_t num_exts;
     custom_ext_methods *exts = NULL;
     RAW_EXTENSION *raw_extensions = NULL;
     const EXTENSION_DEFINITION *thisexd;
@@ -392,16 +437,15 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
      * Initialise server side custom extensions. Client side is done during
      * construction of extensions for the ClientHello.
      */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
         exts = &s->cert->srv_ext;
         custom_ext_init(&s->cert->srv_ext);
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
+    } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
         exts = &s->cert->cli_ext;
     }
 
-    raw_extensions = OPENSSL_zalloc((OSSL_NELEM(ext_defs)
-                                     + (exts != NULL ? exts->meths_count : 0))
-                                     * sizeof(*raw_extensions));
+    num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0);
+    raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions));
     if (raw_extensions == NULL) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, ERR_R_MALLOC_FAILURE);
@@ -421,10 +465,14 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
         }
         /*
          * Verify this extension is allowed. We only check duplicates for
-         * extensions that we recognise.
+         * extensions that we recognise. We also have a special case for the
+         * PSK extension, which must be the last one in the ClientHello.
          */
         if (!verify_extension(s, context, type, exts, raw_extensions, &thisex)
-                || (thisex != NULL && thisex->present == 1)) {
+                || (thisex != NULL && thisex->present == 1)
+                || (type == TLSEXT_TYPE_psk
+                    && (context & SSL_EXT_CLIENT_HELLO) != 0
+                    && PACKET_remaining(&extensions) != 0)) {
             SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
             *al = SSL_AD_ILLEGAL_PARAMETER;
             goto err;
@@ -450,6 +498,8 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
     }
 
     *res = raw_extensions;
+    if (len != NULL)
+        *len = num_exts;
     return 1;
 
  err:
@@ -520,7 +570,7 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
      */
     if ((!s->hit || !s->server)
             && (context
-                & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
+                & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
             && custom_ext_parse(s, s->server, currext->type,
                                 PACKET_data(&currext->data),
                                 PACKET_remaining(&currext->data),
@@ -545,9 +595,9 @@ int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
     const EXTENSION_DEFINITION *thisexd;
 
     /* Calculate the number of extensions in the extensions list */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
         numexts += s->cert->srv_ext.meths_count;
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
+    } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
         numexts += s->cert->cli_ext.meths_count;
     }
 
@@ -598,15 +648,16 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
                 * If extensions are of zero length then we don't even add the
                 * extensions length bytes to a ClientHello/ServerHello in SSLv3
                 */
-            || ((context & (EXT_CLIENT_HELLO | EXT_TLS1_2_SERVER_HELLO)) != 0
-               && s->version == SSL3_VERSION
-               && !WPACKET_set_flags(pkt,
+            || ((context &
+                 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0
+                && s->version == SSL3_VERSION
+                && !WPACKET_set_flags(pkt,
                                      WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) {
         SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
-    if ((context & EXT_CLIENT_HELLO) != 0) {
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
         reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
         if (reason != 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_EXTENSIONS, reason);
@@ -615,10 +666,10 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
     }
 
     /* Add custom extensions first */
-    if ((context & EXT_CLIENT_HELLO) != 0) {
+    if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
         custom_ext_init(&s->cert->cli_ext);
         addcustom = 1;
-    } else if ((context & EXT_TLS1_2_SERVER_HELLO) != 0) {
+    } else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) {
         /*
          * We already initialised the custom extensions during ClientHello
          * parsing.
@@ -648,18 +699,18 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
 
         /* Check if this extension is defined for our protocol. If not, skip */
         if ((SSL_IS_DTLS(s)
-                    && (thisexd->context & EXT_TLS_IMPLEMENTATION_ONLY)
+                    && (thisexd->context & SSL_EXT_TLS_IMPLEMENTATION_ONLY)
                        != 0)
                 || (s->version == SSL3_VERSION
-                        && (thisexd->context & EXT_SSL3_ALLOWED) == 0)
+                        && (thisexd->context & SSL_EXT_SSL3_ALLOWED) == 0)
                 || (SSL_IS_TLS13(s)
-                    && (thisexd->context & EXT_TLS1_2_AND_BELOW_ONLY)
+                    && (thisexd->context & SSL_EXT_TLS1_2_AND_BELOW_ONLY)
                        != 0)
                 || (!SSL_IS_TLS13(s)
-                    && (thisexd->context & EXT_TLS1_3_ONLY) != 0
-                    && (context & EXT_CLIENT_HELLO) == 0)
-                || ((thisexd->context & EXT_TLS1_3_ONLY) != 0
-                    && (context & EXT_CLIENT_HELLO) != 0
+                    && (thisexd->context & SSL_EXT_TLS1_3_ONLY) != 0
+                    && (context & SSL_EXT_CLIENT_HELLO) == 0)
+                || ((thisexd->context & SSL_EXT_TLS1_3_ONLY) != 0
+                    && (context & SSL_EXT_CLIENT_HELLO) != 0
                     && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))
                 || construct == NULL)
             continue;
@@ -843,8 +894,8 @@ static int init_alpn(SSL *s, unsigned int context)
 {
     OPENSSL_free(s->s3->alpn_selected);
     s->s3->alpn_selected = NULL;
+    s->s3->alpn_selected_len = 0;
     if (s->server) {
-        s->s3->alpn_selected_len = 0;
         OPENSSL_free(s->s3->alpn_proposed);
         s->s3->alpn_proposed = NULL;
         s->s3->alpn_proposed_len = 0;
@@ -908,7 +959,7 @@ static int init_srp(SSL *s, unsigned int context)
 
 static int init_etm(SSL *s, unsigned int context)
 {
-    s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;
+    s->ext.use_etm = 0;
 
     return 1;
 }
@@ -939,6 +990,47 @@ static int final_ems(SSL *s, unsigned int context, int sent, int *al)
     return 1;
 }
 
+static int init_certificate_authorities(SSL *s, unsigned int context)
+{
+    sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free);
+    s->s3->tmp.peer_ca_names = NULL;
+    return 1;
+}
+
+static int tls_construct_certificate_authorities(SSL *s, WPACKET *pkt,
+                                                 unsigned int context, X509 *x,
+                                                 size_t chainidx, int *al)
+{
+    const STACK_OF(X509_NAME) *ca_sk = SSL_get0_CA_list(s);
+
+    if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0)
+        return 1;
+
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_certificate_authorities)
+        || !WPACKET_start_sub_packet_u16(pkt)
+        || !construct_ca_names(s, pkt)
+        || !WPACKET_close(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES,
+               ERR_R_INTERNAL_ERROR);
+        return 0;
+    }
+
+    return 1;
+}
+
+static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
+{
+    if (!parse_ca_names(s, pkt, al))
+        return 0;
+    if (PACKET_remaining(pkt) != 0) {
+        *al = SSL_AD_DECODE_ERROR;
+        return 0;
+    }
+    return 1;
+}
+
 #ifndef OPENSSL_NO_SRTP
 static int init_srtp(SSL *s, unsigned int context)
 {
@@ -960,7 +1052,7 @@ static int final_sig_algs(SSL *s, unsigned int context, int sent, int *al)
     return 1;
 }
 
-
+#ifndef OPENSSL_NO_EC
 static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
 {
     if (!SSL_IS_TLS13(s))
@@ -968,29 +1060,103 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
 
     /*
      * If
+     *     we are a client
+     *     AND
      *     we have no key_share
      *     AND
      *     (we are not resuming
      *      OR the kex_mode doesn't allow non key_share resumes)
      * THEN
-     *     fail
+     *     fail;
      */
-    if (((s->server && s->s3->peer_tmp == NULL) || (!s->server && !sent))
+    if (!s->server
+            && !sent
             && (!s->hit
                 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) {
-        /* No suitable share */
-        if (s->server && s->hello_retry_request == 0 && sent) {
-            s->hello_retry_request = 1;
-            return 1;
-        }
-
         /* Nothing left we can do - just fail */
         *al = SSL_AD_HANDSHAKE_FAILURE;
         SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
         return 0;
     }
+    /*
+     * If
+     *     we are a server
+     *     AND
+     *     we have no key_share
+     * THEN
+     *     If
+     *         we didn't already send a HelloRetryRequest
+     *         AND
+     *         the client sent a key_share extension
+     *         AND
+     *         (we are not resuming
+     *          OR the kex_mode allows key_share resumes)
+     *         AND
+     *         a shared group exists
+     *     THEN
+     *         send a HelloRetryRequest
+     *     ELSE If
+     *         we are not resuming
+     *         OR
+     *         the kex_mode doesn't allow non key_share resumes
+     *     THEN
+     *         fail;
+     */
+    if (s->server && s->s3->peer_tmp == NULL) {
+        /* No suitable share */
+        if (s->hello_retry_request == 0 && sent
+                && (!s->hit
+                    || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE)
+                       != 0)) {
+            const unsigned char *pcurves, *pcurvestmp, *clntcurves;
+            size_t num_curves, clnt_num_curves, i;
+            unsigned int group_id = 0;
+
+            /* Check if a shared group exists */
+
+            /* Get the clients list of supported groups. */
+            if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
+                *al = SSL_AD_INTERNAL_ERROR;
+                SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
+
+            /* Get our list of available groups */
+            if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
+                *al = SSL_AD_INTERNAL_ERROR;
+                SSLerr(SSL_F_FINAL_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+                return 0;
+            }
+
+            /* Find the first group we allow that is also in client's list */
+            for (i = 0, pcurvestmp = pcurves; i < num_curves;
+                 i++, pcurvestmp += 2) {
+                group_id = bytestogroup(pcurvestmp);
+
+                if (check_in_list(s, group_id, clntcurves, clnt_num_curves, 1))
+                    break;
+            }
+
+            if (i < num_curves) {
+                /* A shared group exists so send a HelloRetryRequest */
+                s->s3->group_id = group_id;
+                s->hello_retry_request = 1;
+                return 1;
+            }
+        }
+        if (!s->hit
+                || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) {
+            /* Nothing left we can do - just fail */
+            *al = SSL_AD_HANDSHAKE_FAILURE;
+            SSLerr(SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
+            return 0;
+        }
+    }
+
+    /* We have a key_share so don't send any more HelloRetryRequest messages */
+    if (s->server)
+        s->hello_retry_request = 0;
 
-    s->hello_retry_request = 0;
     /*
      * For a client side resumption with no key_share we need to generate
      * the handshake secret (otherwise this is done during key_share
@@ -1004,6 +1170,7 @@ static int final_key_share(SSL *s, unsigned int context, int sent, int *al)
 
     return 1;
 }
+#endif
 
 static int init_psk_kex_modes(SSL *s, unsigned int context)
 {
@@ -1059,13 +1226,52 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
         goto err;
     }
 
+    if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) {
+        SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
     /*
-     * Get a hash of the ClientHello up to the start of the binders.
-     * TODO(TLS1.3): This will need to be tweaked when we implement
-     * HelloRetryRequest to include the digest of the previous messages here.
+     * Get a hash of the ClientHello up to the start of the binders. If we are
+     * following a HelloRetryRequest then this includes the hash of the first
+     * ClientHello and the HelloRetryRequest itself.
      */
-    if (EVP_DigestInit_ex(mctx, md, NULL) <= 0
-            || EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
+    if (s->hello_retry_request) {
+        size_t hdatalen;
+        void *hdata;
+
+        hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
+        if (hdatalen <= 0) {
+            SSLerr(SSL_F_TLS_PSK_DO_BINDER, SSL_R_BAD_HANDSHAKE_LENGTH);
+            goto err;
+        }
+
+        /*
+         * For servers the handshake buffer data will include the second
+         * ClientHello - which we don't want - so we need to take that bit off.
+         */
+        if (s->server) {
+            PACKET hashprefix, msg;
+
+            /* Find how many bytes are left after the first two messages */
+            if (!PACKET_buf_init(&hashprefix, hdata, hdatalen)
+                    || !PACKET_forward(&hashprefix, 1)
+                    || !PACKET_get_length_prefixed_3(&hashprefix, &msg)
+                    || !PACKET_forward(&hashprefix, 1)
+                    || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) {
+                SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
+                goto err;
+            }
+            hdatalen -= PACKET_remaining(&hashprefix);
+        }
+
+        if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) {
+            SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0
             || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
         SSLerr(SSL_F_TLS_PSK_DO_BINDER, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -1104,3 +1310,32 @@ int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart,
 
     return ret;
 }
+
+static int final_early_data(SSL *s, unsigned int context, int sent, int *al)
+{
+    if (!s->server || !sent)
+        return 1;
+
+    if (s->max_early_data == 0
+            || !s->hit
+            || s->session->ext.tick_identity != 0
+            || s->early_data_state != SSL_EARLY_DATA_ACCEPTING
+            || !s->ext.early_data_ok
+            || s->hello_retry_request
+            || s->s3->alpn_selected_len != s->session->ext.alpn_selected_len
+            || (s->s3->alpn_selected_len > 0
+                && memcmp(s->s3->alpn_selected, s->session->ext.alpn_selected,
+                          s->s3->alpn_selected_len) != 0)) {
+        s->ext.early_data = SSL_EARLY_DATA_REJECTED;
+    } else {
+        s->ext.early_data = SSL_EARLY_DATA_ACCEPTED;
+
+        if (!tls13_change_cipher_state(s,
+                    SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
+    }
+
+    return 1;
+}