Allow a client to send early_data with SNI if the session has no SNI
[openssl.git] / ssl / statem / extensions_clnt.c
index 7d2a4b04a5f135c32492502836e9d5ccbefe19a5..0dc1c49734ede1d7345d434a1b4af8a519aa2401 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016-2017 The OpenSSL Project Authors. 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
@@ -7,17 +7,18 @@
  * https://www.openssl.org/source/license.html
  */
 
-#include <assert.h>
 #include <openssl/ocsp.h>
 #include "../ssl_locl.h"
+#include "internal/cryptlib.h"
 #include "statem_locl.h"
 
-int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, unsigned int context,
-                                   X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx, int *al)
 {
     /* Add RI if renegotiating */
     if (!s->renegotiate)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
             || !WPACKET_start_sub_packet_u16(pkt)
@@ -25,17 +26,18 @@ int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, unsigned int context,
                                s->s3->previous_client_finished_len)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_RENEGOTIATE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, unsigned int context,
-                                   X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_server_name(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx, int *al)
 {
     if (s->ext.hostname == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /* Add TLS extension servername to the Client Hello message */
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
@@ -49,19 +51,44 @@ int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SERVER_NAME, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
+}
+
+/* Push a Max Fragment Len extension into ClientHello */
+EXT_RETURN tls_construct_ctos_maxfragmentlen(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
+{
+    if (s->ext.max_fragment_len_mode == TLSEXT_max_fragment_length_DISABLED)
+        return EXT_RETURN_NOT_SENT;
+
+    /* Add Max Fragment Length extension if client enabled it. */
+    /*-
+     * 4 bytes for this extension type and extension length
+     * 1 byte for the Max Fragment Length code value.
+     */
+    if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_max_fragment_length)
+            /* Sub-packet for Max Fragment Length extension (1 byte) */
+            || !WPACKET_start_sub_packet_u16(pkt)
+            || !WPACKET_put_bytes_u8(pkt, s->ext.max_fragment_len_mode)
+            || !WPACKET_close(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_MAXFRAGMENTLEN, ERR_R_INTERNAL_ERROR);
+        return EXT_RETURN_FAIL;
+    }
+
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_SRP
-int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     /* Add SRP username if there is one */
     if (s->srp_ctx.login == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_srp)
                /* Sub-packet for SRP extension */
@@ -74,10 +101,10 @@ int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SRP, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
@@ -108,14 +135,15 @@ static int use_ecc(SSL *s)
     return 0;
 }
 
-int tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt, unsigned int context,
-                                     X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx, int *al)
 {
     const unsigned char *pformats;
     size_t num_formats;
 
     if (!use_ecc(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /* Add TLS extension ECPointFormats to the ClientHello message */
     tls1_get_formatlist(s, &pformats, &num_formats);
@@ -126,32 +154,27 @@ int tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_sub_memcpy_u8(pkt, pformats, num_formats)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
-                                        unsigned int context, X509 *x,
-                                        size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
+                                               unsigned int context, X509 *x,
+                                               size_t chainidx, int *al)
 {
-    const unsigned char *pcurves = NULL, *pcurvestmp;
-    size_t num_curves = 0, i;
+    const uint16_t *pgroups = NULL;
+    size_t num_groups = 0, i;
 
     if (!use_ecc(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /*
      * Add TLS extension supported_groups to the ClientHello message
      */
     /* TODO(TLS1.3): Add support for DHE groups */
-    if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
-               ERR_R_INTERNAL_ERROR);
-        return 0;
-    }
-    pcurvestmp = pcurves;
+    tls1_get_supported_groups(s, &pgroups, &num_groups);
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
                /* Sub-packet for supported_groups extension */
@@ -159,37 +182,38 @@ int tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt,
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
                ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
     /* Copy curve ID if supported */
-    for (i = 0; i < num_curves; i++, pcurvestmp += 2) {
-        if (tls_curve_allowed(s, pcurvestmp, SSL_SECOP_CURVE_SUPPORTED)) {
-            if (!WPACKET_put_bytes_u8(pkt, pcurvestmp[0])
-                || !WPACKET_put_bytes_u8(pkt, pcurvestmp[1])) {
+    for (i = 0; i < num_groups; i++) {
+        uint16_t ctmp = pgroups[i];
+
+        if (tls_curve_allowed(s, ctmp, SSL_SECOP_CURVE_SUPPORTED)) {
+            if (!WPACKET_put_bytes_u16(pkt, ctmp)) {
                     SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
                            ERR_R_INTERNAL_ERROR);
-                    return 0;
+                    return EXT_RETURN_FAIL;
                 }
         }
     }
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_GROUPS,
                ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
-                                      unsigned int context, X509 *x,
-                                      size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
 {
     size_t ticklen;
 
     if (!tls_use_ticket(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!s->new_session && s->session != NULL
             && s->session->ext.tick != NULL
@@ -202,7 +226,7 @@ int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
         if (s->session->ext.tick == NULL) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SESSION_TICKET,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
         memcpy(s->session->ext.tick,
                s->ext.session_ticket->data, ticklen);
@@ -213,25 +237,26 @@ int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt,
 
     if (ticklen == 0 && s->ext.session_ticket != NULL &&
             s->ext.session_ticket->data == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
             || !WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick, ticklen)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, unsigned int context,
-                                X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt,
+                                       unsigned int context, X509 *x,
+                                       size_t chainidx, int *al)
 {
     size_t salglen;
     const uint16_t *salg;
 
     if (!SSL_CLIENT_USE_SIGALGS(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     salglen = tls12_get_psigalgs(s, 1, &salg);
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signature_algorithms)
@@ -243,25 +268,25 @@ int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SIG_ALGS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_OCSP
-int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
-                                      unsigned int context, X509 *x,
-                                      size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
 {
     int i;
 
     /* This extension isn't defined for client Certificates */
     if (x != NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
                /* Sub-packet for status request extension */
@@ -270,7 +295,7 @@ int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
                /* Sub-packet for the ids */
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
     for (i = 0; i < sk_OCSP_RESPID_num(s->ext.ocsp.ids); i++) {
         unsigned char *idbytes;
@@ -283,13 +308,13 @@ int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
                 || i2d_OCSP_RESPID(id, &idbytes) != idlen) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
     }
     if (!WPACKET_close(pkt)
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
     if (s->ext.ocsp.exts) {
         unsigned char *extbytes;
@@ -298,31 +323,31 @@ int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt,
         if (extlen < 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
         if (!WPACKET_allocate_bytes(pkt, extlen, &extbytes)
                 || i2d_X509_EXTENSIONS(s->ext.ocsp.exts, &extbytes)
                    != extlen) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
        }
     }
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_npn(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (s->ctx->ext.npn_select_cb == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /*
      * The client advertises an empty extension to indicate its support
@@ -331,20 +356,20 @@ int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_next_proto_neg)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_NPN, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                            size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, unsigned int context,
+                                   X509 *x, size_t chainidx, int *al)
 {
     s->s3->alpn_sent = 0;
 
     if (s->ext.alpn == NULL || !SSL_IS_FIRST_HANDSHAKE(s))
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt,
                 TLSEXT_TYPE_application_layer_protocol_negotiation)
@@ -353,23 +378,24 @@ int tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
             || !WPACKET_sub_memcpy_u16(pkt, s->ext.alpn, s->ext.alpn_len)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_ALPN, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
     s->s3->alpn_sent = 1;
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 
 #ifndef OPENSSL_NO_SRTP
-int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
-                                X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt,
+                                       unsigned int context, X509 *x,
+                                       size_t chainidx, int *al)
 {
     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = SSL_get_srtp_profiles(s);
     int i, end;
 
     if (clnt == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
                /* Sub-packet for SRTP extension */
@@ -377,7 +403,7 @@ int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
                /* Sub-packet for the protection profile list */
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     end = sk_SRTP_PROTECTION_PROFILE_num(clnt);
@@ -387,7 +413,7 @@ int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
 
         if (prof == NULL || !WPACKET_put_bytes_u16(pkt, prof->id)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
     }
     if (!WPACKET_close(pkt)
@@ -395,64 +421,64 @@ int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_put_bytes_u8(pkt, 0)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_USE_SRTP, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_ctos_etm(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_etm(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_encrypt_then_mac)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_ETM, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_CT
-int tls_construct_ctos_sct(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_sct(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (s->ct_validation_callback == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /* Not defined for client Certificates */
     if (x != NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_signed_certificate_timestamp)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SCT, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_ctos_ems(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_ems(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EMS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
-                                          unsigned int context, X509 *x,
-                                          size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
+                                                 unsigned int context, X509 *x,
+                                                 size_t chainidx, int *al)
 {
     int currv, min_version, max_version, reason;
 
@@ -461,13 +487,13 @@ int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
             || !WPACKET_start_sub_packet_u8(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
                ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    reason = ssl_get_client_min_max_version(s, &min_version, &max_version);
+    reason = ssl_get_min_max_version(s, &min_version, &max_version);
     if (reason != 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS, reason);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /*
@@ -481,63 +507,74 @@ int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt,
             if (!WPACKET_put_bytes_u16(pkt, TLS1_3_VERSION_DRAFT)) {
                 SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
                        ERR_R_INTERNAL_ERROR);
-                return 0;
+                return EXT_RETURN_FAIL;
             }
         } else if (!WPACKET_put_bytes_u16(pkt, currv)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
     }
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_SUPPORTED_VERSIONS,
                ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 /*
- * Construct a psk_kex_modes extension. We only have two modes we know about
- * at this stage, so we send both.
+ * Construct a psk_kex_modes extension.
  */
-int tls_construct_ctos_psk_kex_modes(SSL *s, WPACKET *pkt, unsigned int context,
-                                     X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_psk_kex_modes(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx, int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
-    /*
-     * TODO(TLS1.3): Do we want this list to be configurable? For now we always
-     * just send both supported modes
-     */
+    int nodhe = s->options & SSL_OP_ALLOW_NO_DHE_KEX;
+
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk_kex_modes)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_start_sub_packet_u8(pkt)
             || !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE_DHE)
-            || !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE)
+            || (nodhe && !WPACKET_put_bytes_u8(pkt, TLSEXT_KEX_MODE_KE))
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK_KEX_MODES, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_KE | TLSEXT_KEX_MODE_FLAG_KE_DHE;
+    s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_KE_DHE;
+    if (nodhe)
+        s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
 #endif
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_TLS1_3
 static int add_key_share(SSL *s, WPACKET *pkt, unsigned int curve_id)
 {
-    unsigned char *encoded_point;
-    EVP_PKEY *key_share_key;
+    unsigned char *encoded_point = NULL;
+    EVP_PKEY *key_share_key = NULL;
     size_t encodedlen;
 
-    key_share_key = ssl_generate_pkey_curve(curve_id);
-    if (key_share_key == NULL) {
-        SSLerr(SSL_F_ADD_KEY_SHARE, ERR_R_EVP_LIB);
-        return 0;
+    if (s->s3->tmp.pkey != NULL) {
+        if (!ossl_assert(s->hello_retry_request)) {
+            SSLerr(SSL_F_ADD_KEY_SHARE, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+        /*
+         * Could happen if we got an HRR that wasn't requesting a new key_share
+         */
+        key_share_key = s->s3->tmp.pkey;
+    } else {
+        key_share_key = ssl_generate_pkey_group(curve_id);
+        if (key_share_key == NULL) {
+            SSLerr(SSL_F_ADD_KEY_SHARE, ERR_R_EVP_LIB);
+            return 0;
+        }
     }
 
     /* Encode the public key. */
@@ -545,17 +582,14 @@ static int add_key_share(SSL *s, WPACKET *pkt, unsigned int curve_id)
                                                 &encoded_point);
     if (encodedlen == 0) {
         SSLerr(SSL_F_ADD_KEY_SHARE, ERR_R_EC_LIB);
-        EVP_PKEY_free(key_share_key);
-        return 0;
+        goto err;
     }
 
     /* Create KeyShareEntry */
     if (!WPACKET_put_bytes_u16(pkt, curve_id)
             || !WPACKET_sub_memcpy_u16(pkt, encoded_point, encodedlen)) {
         SSLerr(SSL_F_ADD_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        EVP_PKEY_free(key_share_key);
-        OPENSSL_free(encoded_point);
-        return 0;
+        goto err;
     }
 
     /*
@@ -568,16 +602,22 @@ static int add_key_share(SSL *s, WPACKET *pkt, unsigned int curve_id)
     OPENSSL_free(encoded_point);
 
     return 1;
+ err:
+    if (s->s3->tmp.pkey == NULL)
+        EVP_PKEY_free(key_share_key);
+    OPENSSL_free(encoded_point);
+    return 0;
 }
 #endif
 
-int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, unsigned int context,
-                                 X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_key_share(SSL *s, WPACKET *pkt,
+                                        unsigned int context, X509 *x,
+                                        size_t chainidx, int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
-    size_t i, num_curves = 0;
-    const unsigned char *pcurves = NULL;
-    unsigned int curve_id = 0;
+    size_t i, num_groups = 0;
+    const uint16_t *pgroups = NULL;
+    uint16_t curve_id = 0;
 
     /* key_share extension */
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
@@ -586,19 +626,10 @@ int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, unsigned int context,
                /* KeyShare list sub-packet */
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
-    }
-
-    if (s->s3->tmp.pkey != NULL) {
-        /* Shouldn't happen! */
-        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
-    }
+    tls1_get_supported_groups(s, &pgroups, &num_groups);
 
     /*
      * TODO(TLS1.3): Make the number of key_shares sent configurable. For
@@ -607,41 +638,41 @@ int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, unsigned int context,
     if (s->s3->group_id != 0) {
         curve_id = s->s3->group_id;
     } else {
-        for (i = 0; i < num_curves; i++, pcurves += 2) {
+        for (i = 0; i < num_groups; i++) {
 
-            if (!tls_curve_allowed(s, pcurves, SSL_SECOP_CURVE_SUPPORTED))
+            if (!tls_curve_allowed(s, pgroups[i], SSL_SECOP_CURVE_SUPPORTED))
                 continue;
 
-            curve_id = bytestogroup(pcurves);
+            curve_id = pgroups[i];
             break;
         }
     }
 
     if (curve_id == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     if (!add_key_share(s, pkt, curve_id))
-        return 0;
+        return EXT_RETURN_FAIL;
 
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 #endif
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
-                              X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
+                                     X509 *x, size_t chainidx, int *al)
 {
-    int ret = 0;
+    EXT_RETURN ret = EXT_RETURN_FAIL;
 
     /* Should only be set if we've had an HRR */
     if (s->ext.tls13_cookie_len == 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_cookie)
                /* Extension data sub-packet */
@@ -653,7 +684,7 @@ int tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
         goto end;
     }
 
-    ret = 1;
+    ret = EXT_RETURN_SENT;
  end:
     OPENSSL_free(s->ext.tls13_cookie);
     s->ext.tls13_cookie = NULL;
@@ -662,21 +693,96 @@ int tls_construct_ctos_cookie(SSL *s, WPACKET *pkt, unsigned int context,
     return ret;
 }
 
-int tls_construct_ctos_early_data(SSL *s, WPACKET *pkt, unsigned int context,
-                                  X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_early_data(SSL *s, WPACKET *pkt,
+                                         unsigned int context, X509 *x,
+                                         size_t chainidx, int *al)
 {
+    const unsigned char *id = NULL;
+    size_t idlen = 0;
+    SSL_SESSION *psksess = NULL;
+    SSL_SESSION *edsess = NULL;
+    const EVP_MD *handmd = NULL;
+
+    if (s->hello_retry_request)
+        handmd = ssl_handshake_md(s);
+
+    if (s->psk_use_session_cb != NULL
+            && (!s->psk_use_session_cb(s, handmd, &id, &idlen, &psksess)
+                || (psksess != NULL
+                    && psksess->ssl_version != TLS1_3_VERSION))) {
+        SSL_SESSION_free(psksess);
+        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, SSL_R_BAD_PSK);
+        return EXT_RETURN_FAIL;
+    }
+
+    SSL_SESSION_free(s->psksession);
+    s->psksession = psksess;
+    if (psksess != NULL) {
+        OPENSSL_free(s->psksession_id);
+        s->psksession_id = OPENSSL_memdup(id, idlen);
+        if (s->psksession_id == NULL) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+        s->psksession_id_len = idlen;
+    }
+
     if (s->early_data_state != SSL_EARLY_DATA_CONNECTING
-            || s->session->ext.max_early_data == 0) {
+            || (s->session->ext.max_early_data == 0
+                && (psksess == NULL || psksess->ext.max_early_data == 0))) {
         s->max_early_data = 0;
-        return 1;
+        return EXT_RETURN_NOT_SENT;
+    }
+    edsess = s->session->ext.max_early_data != 0 ? s->session : psksess;
+    s->max_early_data = edsess->ext.max_early_data;
+
+    if (edsess->ext.hostname != NULL) {
+        if (s->ext.hostname == NULL
+                || (s->ext.hostname != NULL
+                    && strcmp(s->ext.hostname, edsess->ext.hostname) != 0)) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
+                   SSL_R_INCONSISTENT_EARLY_DATA_SNI);
+            return EXT_RETURN_FAIL;
+        }
+    }
+
+    if ((s->ext.alpn == NULL && edsess->ext.alpn_selected != NULL)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
+               SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
+        return EXT_RETURN_FAIL;
+    }
+
+    /*
+     * Verify that we are offering an ALPN protocol consistent with the early
+     * data.
+     */
+    if (edsess->ext.alpn_selected != NULL) {
+        PACKET prots, alpnpkt;
+        int found = 0;
+
+        if (!PACKET_buf_init(&prots, s->ext.alpn, s->ext.alpn_len)) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
+            return EXT_RETURN_FAIL;
+        }
+        while (PACKET_get_length_prefixed_1(&prots, &alpnpkt)) {
+            if (PACKET_equal(&alpnpkt, edsess->ext.alpn_selected,
+                             edsess->ext.alpn_selected_len)) {
+                found = 1;
+                break;
+            }
+        }
+        if (!found) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA,
+                   SSL_R_INCONSISTENT_EARLY_DATA_ALPN);
+            return EXT_RETURN_FAIL;
+        }
     }
-    s->max_early_data = s->session->ext.max_early_data;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_EARLY_DATA, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /*
@@ -684,8 +790,9 @@ int tls_construct_ctos_early_data(SSL *s, WPACKET *pkt, unsigned int context,
      * extension, we set it to accepted.
      */
     s->ext.early_data = SSL_EARLY_DATA_REJECTED;
+    s->ext.early_data_ok = 1;
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #define F5_WORKAROUND_MIN_MSG_LEN   0xff
@@ -705,14 +812,15 @@ int tls_construct_ctos_early_data(SSL *s, WPACKET *pkt, unsigned int context,
  */
 #define PSK_PRE_BINDER_OVERHEAD (2 + 2 + 2 + 2 + 4 + 2 + 1)
 
-int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, unsigned int context,
-                               X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_padding(SSL *s, WPACKET *pkt,
+                                      unsigned int context, X509 *x,
+                                      size_t chainidx, int *al)
 {
     unsigned char *padbytes;
     size_t hlen;
 
     if ((s->options & SSL_OP_TLSEXT_PADDING) == 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /*
      * Add padding to workaround bugs in F5 terminators. See RFC7685.
@@ -722,7 +830,7 @@ int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, unsigned int context,
      */
     if (!WPACKET_get_total_written(pkt, &hlen)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PADDING, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /*
@@ -750,36 +858,39 @@ int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, unsigned int context,
 
         /*
          * Take off the size of extension header itself (2 bytes for type and
-         * 2 bytes for length bytes)
+         * 2 bytes for length bytes), but ensure that the extension is at least
+         * 1 byte long so as not to have an empty extension last (WebSphere 7.x,
+         * 8.x are intolerant of that condition)
          */
-        if (hlen >= 4)
+        if (hlen > 4)
             hlen -= 4;
         else
-            hlen = 0;
+            hlen = 1;
 
         if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_padding)
                 || !WPACKET_sub_allocate_bytes_u16(pkt, hlen, &padbytes)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PADDING, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
         memset(padbytes, 0, hlen);
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 /*
  * Construct the pre_shared_key extension
  */
-int tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
-    uint32_t now, agesec, agems;
-    size_t hashsize, binderoffset, msglen;
-    unsigned char *binder = NULL, *msgstart = NULL;
-    const EVP_MD *md;
-    int ret = 0;
+    uint32_t now, agesec, agems = 0;
+    size_t reshashsize = 0, pskhashsize = 0, binderoffset, msglen;
+    unsigned char *resbinder = NULL, *pskbinder = NULL, *msgstart = NULL;
+    const EVP_MD *handmd = NULL, *mdres = NULL, *mdpsk = NULL;
+    EXT_RETURN ret = EXT_RETURN_FAIL;
+    int dores = 0;
 
     s->session->ext.tick_identity = TLSEXT_PSK_BAD_IDENTITY;
 
@@ -794,76 +905,135 @@ int tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
      * so don't add this extension.
      */
     if (s->session->ssl_version != TLS1_3_VERSION
-            || s->session->ext.ticklen == 0)
-        return 1;
+            || (s->session->ext.ticklen == 0 && s->psksession == NULL))
+        return EXT_RETURN_NOT_SENT;
 
-    if (s->session->cipher == NULL) {
-        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
-        goto err;
-    }
+    if (s->hello_retry_request)
+        handmd = ssl_handshake_md(s);
 
-    md = ssl_md(s->session->cipher->algorithm2);
-    if (md == NULL) {
-        /* Don't recognize this cipher so we can't use the session. Ignore it */
-        return 1;
-    }
+    if (s->session->ext.ticklen != 0) {
+        /* Get the digest associated with the ciphersuite in the session */
+        if (s->session->cipher == NULL) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+        mdres = ssl_md(s->session->cipher->algorithm2);
+        if (mdres == NULL) {
+            /*
+             * Don't recognize this cipher so we can't use the session.
+             * Ignore it
+             */
+            goto dopsksess;
+        }
+
+        if (s->hello_retry_request && mdres != handmd) {
+            /*
+             * Selected ciphersuite hash does not match the hash for the session
+             * so we can't use it.
+             */
+            goto dopsksess;
+        }
 
-    if (s->hello_retry_request && md != ssl_handshake_md(s)) {
         /*
-         * Selected ciphersuite hash does not match the hash for the session so
-         * we can't use it.
+         * Technically the C standard just says time() returns a time_t and says
+         * nothing about the encoding of that type. In practice most
+         * implementations follow POSIX which holds it as an integral type in
+         * seconds since epoch. We've already made the assumption that we can do
+         * this in multiple places in the code, so portability shouldn't be an
+         * issue.
          */
-        return 1;
-    }
+        now = (uint32_t)time(NULL);
+        agesec = now - (uint32_t)s->session->time;
 
-    /*
-     * Technically the C standard just says time() returns a time_t and says
-     * nothing about the encoding of that type. In practice most implementations
-     * follow POSIX which holds it as an integral type in seconds since epoch.
-     * We've already made the assumption that we can do this in multiple places
-     * in the code, so portability shouldn't be an issue.
-     */
-    now = (uint32_t)time(NULL);
-    agesec = now - (uint32_t)s->session->time;
+        if (s->session->ext.tick_lifetime_hint < agesec) {
+            /* Ticket is too old. Ignore it. */
+            goto dopsksess;
+        }
 
-    if (s->session->ext.tick_lifetime_hint < agesec) {
-        /* Ticket is too old. Ignore it. */
-        return 1;
-    }
+        /*
+         * Calculate age in ms. We're just doing it to nearest second. Should be
+         * good enough.
+         */
+        agems = agesec * (uint32_t)1000;
 
-    /*
-     * Calculate age in ms. We're just doing it to nearest second. Should be
-     * good enough.
-     */
-    agems = agesec * (uint32_t)1000;
+        if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
+            /*
+             * Overflow. Shouldn't happen unless this is a *really* old session.
+             * If so we just ignore it.
+             */
+            goto dopsksess;
+        }
 
-    if (agesec != 0 && agems / (uint32_t)1000 != agesec) {
         /*
-         * Overflow. Shouldn't happen unless this is a *really* old session. If
-         * so we just ignore it.
+         * Obfuscate the age. Overflow here is fine, this addition is supposed
+         * to be mod 2^32.
          */
-        return 1;
+        agems += s->session->ext.tick_age_add;
+
+        reshashsize = EVP_MD_size(mdres);
+        dores = 1;
     }
 
-    /*
-     * Obfuscate the age. Overflow here is fine, this addition is supposed to
-     * be mod 2^32.
-     */
-    agems += s->session->ext.tick_age_add;
+ dopsksess:
+    if (!dores && s->psksession == NULL)
+        return EXT_RETURN_NOT_SENT;
 
-    hashsize = EVP_MD_size(md);
+    if (s->psksession != NULL) {
+        mdpsk = ssl_md(s->psksession->cipher->algorithm2);
+        if (mdpsk == NULL) {
+            /*
+             * Don't recognize this cipher so we can't use the session.
+             * If this happens it's an application bug.
+             */
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, SSL_R_BAD_PSK);
+            goto err;
+        }
+
+        if (s->hello_retry_request && mdpsk != handmd) {
+            /*
+             * Selected ciphersuite hash does not match the hash for the PSK
+             * session. This is an application bug.
+             */
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, SSL_R_BAD_PSK);
+            goto err;
+        }
+
+        pskhashsize = EVP_MD_size(mdpsk);
+    }
 
     /* Create the extension, but skip over the binder for now */
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
             || !WPACKET_start_sub_packet_u16(pkt)
-            || !WPACKET_start_sub_packet_u16(pkt)
-            || !WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
-                                       s->session->ext.ticklen)
-            || !WPACKET_put_bytes_u32(pkt, agems)
-            || !WPACKET_close(pkt)
+            || !WPACKET_start_sub_packet_u16(pkt)) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    if (dores) {
+        if (!WPACKET_sub_memcpy_u16(pkt, s->session->ext.tick,
+                                           s->session->ext.ticklen)
+                || !WPACKET_put_bytes_u32(pkt, agems)) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (s->psksession != NULL) {
+        if (!WPACKET_sub_memcpy_u16(pkt, s->psksession_id,
+                                    s->psksession_id_len)
+                || !WPACKET_put_bytes_u32(pkt, 0)) {
+            SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (!WPACKET_close(pkt)
             || !WPACKET_get_total_written(pkt, &binderoffset)
             || !WPACKET_start_sub_packet_u16(pkt)
-            || !WPACKET_sub_allocate_bytes_u8(pkt, hashsize, &binder)
+            || (dores
+                && !WPACKET_sub_allocate_bytes_u8(pkt, reshashsize, &resbinder))
+            || (s->psksession != NULL
+                && !WPACKET_sub_allocate_bytes_u8(pkt, pskhashsize, &pskbinder))
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)
             || !WPACKET_get_total_written(pkt, &msglen)
@@ -878,19 +1048,30 @@ int tls_construct_ctos_psk(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
 
     msgstart = WPACKET_get_curr(pkt) - msglen;
 
-    if (tls_psk_do_binder(s, md, msgstart, binderoffset, NULL, binder,
-                          s->session, 1) != 1) {
+    if (dores
+            && tls_psk_do_binder(s, mdres, msgstart, binderoffset, NULL,
+                                 resbinder, s->session, 1, 0) != 1) {
         SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
         goto err;
     }
 
-    s->session->ext.tick_identity = 0;
+    if (s->psksession != NULL
+            && tls_psk_do_binder(s, mdpsk, msgstart, binderoffset, NULL,
+                                 pskbinder, s->psksession, 1, 1) != 1) {
+        SSLerr(SSL_F_TLS_CONSTRUCT_CTOS_PSK, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
 
-    ret = 1;
+    if (dores)
+        s->session->ext.tick_identity = 0;
+    if (s->psksession != NULL)
+        s->psksession->ext.tick_identity = (dores ? 1 : 0);
+
+    ret = EXT_RETURN_SENT;
  err:
     return ret;
 #else
-    return 1;
+    return EXT_RETURN_NOT_SENT;
 #endif
 }
 
@@ -906,14 +1087,19 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
     const unsigned char *data;
 
     /* Check for logic errors */
-    assert(expected_len == 0 || s->s3->previous_client_finished_len != 0);
-    assert(expected_len == 0 || s->s3->previous_server_finished_len != 0);
+    if (!ossl_assert(expected_len == 0
+                     || s->s3->previous_client_finished_len != 0)
+        || !ossl_assert(expected_len == 0
+                        || s->s3->previous_server_finished_len != 0)) {
+        *al = SSL_AD_INTERNAL_ERROR;
+        return 0;
+    }
 
     /* Parse the length byte */
     if (!PACKET_get_1_len(pkt, &ilen)) {
         SSLerr(SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
                SSL_R_RENEGOTIATION_ENCODING_ERR);
-        *al = SSL_AD_ILLEGAL_PARAMETER;
+        *al = SSL_AD_DECODE_ERROR;
         return 0;
     }
 
@@ -921,7 +1107,7 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
     if (PACKET_remaining(pkt) != ilen) {
         SSLerr(SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
                SSL_R_RENEGOTIATION_ENCODING_ERR);
-        *al = SSL_AD_ILLEGAL_PARAMETER;
+        *al = SSL_AD_DECODE_ERROR;
         return 0;
     }
 
@@ -929,7 +1115,7 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
     if (ilen != expected_len) {
         SSLerr(SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
                SSL_R_RENEGOTIATION_MISMATCH);
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_ILLEGAL_PARAMETER;
         return 0;
     }
 
@@ -938,7 +1124,7 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
                   s->s3->previous_client_finished_len) != 0) {
         SSLerr(SSL_F_TLS_PARSE_STOC_RENEGOTIATE,
                SSL_R_RENEGOTIATION_MISMATCH);
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_ILLEGAL_PARAMETER;
         return 0;
     }
 
@@ -955,11 +1141,53 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
     return 1;
 }
 
+/* Parse the server's max fragment len extension packet */
+int tls_parse_stoc_maxfragmentlen(SSL *s, PACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
+{
+    unsigned int value;
+
+    if (PACKET_remaining(pkt) != 1 || !PACKET_get_1(pkt, &value)) {
+        *al = TLS1_AD_DECODE_ERROR;
+        return 0;
+    }
+
+    /* |value| should contains a valid max-fragment-length code. */
+    if (!IS_MAX_FRAGMENT_LENGTH_EXT_VALID(value)) {
+        *al = SSL_AD_ILLEGAL_PARAMETER;
+        return 0;
+    }
+
+    /* Must be the same value as client-configured one who was sent to server */
+    /*-
+     * RFC 6066: if a client receives a maximum fragment length negotiation
+     * response that differs from the length it requested, ...
+     * It must abort with SSL_AD_ILLEGAL_PARAMETER alert
+     */
+    if (value != s->ext.max_fragment_len_mode) {
+        *al = SSL_AD_ILLEGAL_PARAMETER;
+        return 0;
+    }
+
+    /*
+     * Maximum Fragment Length Negotiation succeeded.
+     * The negotiated Maximum Fragment Length is binding now.
+     */
+    s->session->ext.max_fragment_len_mode = value;
+
+    return 1;
+}
+
 int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, unsigned int context,
                                X509 *x, size_t chainidx, int *al)
 {
-    if (s->ext.hostname == NULL || PACKET_remaining(pkt) > 0) {
-        *al = SSL_AD_UNRECOGNIZED_NAME;
+    if (s->ext.hostname == NULL) {
+        *al = SSL_AD_INTERNAL_ERROR;
+        return 0;
+    }
+
+    if (PACKET_remaining(pkt) > 0) {
+        *al = SSL_AD_DECODE_ERROR;
         return 0;
     }
 
@@ -1025,10 +1253,14 @@ int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
         return 0;
     }
 
-    if (!tls_use_ticket(s) || PACKET_remaining(pkt) > 0) {
+    if (!tls_use_ticket(s)) {
         *al = SSL_AD_UNSUPPORTED_EXTENSION;
         return 0;
     }
+    if (PACKET_remaining(pkt) > 0) {
+        *al = SSL_AD_DECODE_ERROR;
+        return 0;
+    }
 
     s->ext.ticket_expected = 1;
 
@@ -1043,11 +1275,14 @@ int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, unsigned int context,
      * MUST only be sent if we've requested a status
      * request message. In TLS <= 1.2 it must also be empty.
      */
-    if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp
-            || (!SSL_IS_TLS13(s) && PACKET_remaining(pkt) > 0)) {
+    if (s->ext.status_type != TLSEXT_STATUSTYPE_ocsp) {
         *al = SSL_AD_UNSUPPORTED_EXTENSION;
         return 0;
     }
+    if (!SSL_IS_TLS13(s) && PACKET_remaining(pkt) > 0) {
+        *al = SSL_AD_DECODE_ERROR;
+        return 0;
+    }
 
     if (SSL_IS_TLS13(s)) {
         /* We only know how to handle this if it's for the first Certificate in
@@ -1082,7 +1317,7 @@ int tls_parse_stoc_sct(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
         OPENSSL_free(s->ext.scts);
         s->ext.scts = NULL;
 
-        s->ext.scts_len = size;
+        s->ext.scts_len = (uint16_t)size;
         if (size > 0) {
             s->ext.scts = OPENSSL_malloc(size);
             if (s->ext.scts == NULL
@@ -1092,6 +1327,20 @@ int tls_parse_stoc_sct(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
             }
         }
     } else {
+        ENDPOINT role = (context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0
+                        ? ENDPOINT_CLIENT : ENDPOINT_BOTH;
+
+        /*
+         * If we didn't ask for it then there must be a custom extension,
+         * otherwise this is unsolicited.
+         */
+        if (custom_ext_find(&s->cert->custext, role,
+                            TLSEXT_TYPE_signed_certificate_timestamp,
+                            NULL) == NULL) {
+            *al = TLS1_AD_UNSUPPORTED_EXTENSION;
+            return 0;
+        }
+
         if (custom_ext_parse(s, context,
                              TLSEXT_TYPE_signed_certificate_timestamp,
                              PACKET_data(pkt), PACKET_remaining(pkt),
@@ -1208,6 +1457,24 @@ int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     }
     s->s3->alpn_selected_len = len;
 
+    if (s->session->ext.alpn_selected == NULL
+            || s->session->ext.alpn_selected_len != len
+            || memcmp(s->session->ext.alpn_selected, s->s3->alpn_selected, len)
+               != 0) {
+        /* ALPN not consistent with the old session so cannot use early_data */
+        s->ext.early_data_ok = 0;
+    }
+    if (!s->hit) {
+        /* If a new session then update it with the selected ALPN */
+        s->session->ext.alpn_selected =
+            OPENSSL_memdup(s->s3->alpn_selected, s->s3->alpn_selected_len);
+        if (s->session->ext.alpn_selected == NULL) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
+        s->session->ext.alpn_selected_len = s->s3->alpn_selected_len;
+    }
+
     return 1;
 }
 
@@ -1304,17 +1571,17 @@ int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     }
 
     if (!PACKET_get_net_2(pkt, &group_id)) {
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
 
     if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) {
-        unsigned const char *pcurves = NULL;
-        size_t i, num_curves;
+        const uint16_t *pgroups = NULL;
+        size_t i, num_groups;
 
         if (PACKET_remaining(pkt) != 0) {
-            *al = SSL_AD_HANDSHAKE_FAILURE;
+            *al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_LENGTH_MISMATCH);
             return 0;
         }
@@ -1330,16 +1597,13 @@ int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
         }
 
         /* Validate the selected group is one we support */
-        if (!tls1_get_curvelist(s, 0, &pcurves, &num_curves)) {
-            SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-            return 0;
-        }
-        for (i = 0; i < num_curves; i++, pcurves += 2) {
-            if (group_id == bytestogroup(pcurves))
+        tls1_get_supported_groups(s, &pgroups, &num_groups);
+        for (i = 0; i < num_groups; i++) {
+            if (group_id == pgroups[i])
                 break;
         }
-        if (i >= num_curves
-                || !tls_curve_allowed(s, pcurves, SSL_SECOP_CURVE_SUPPORTED)) {
+        if (i >= num_groups
+                || !tls_curve_allowed(s, group_id, SSL_SECOP_CURVE_SUPPORTED)) {
             *al = SSL_AD_ILLEGAL_PARAMETER;
             SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
             return 0;
@@ -1356,7 +1620,7 @@ int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
          * This isn't for the group that we sent in the original
          * key_share!
          */
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_ILLEGAL_PARAMETER;
         SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
         return 0;
     }
@@ -1376,7 +1640,7 @@ int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     }
     if (!EVP_PKEY_set1_tls_encodedpoint(skey, PACKET_data(&encoded_pt),
                                         PACKET_remaining(&encoded_pt))) {
-        *al = SSL_AD_DECODE_ERROR;
+        *al = SSL_AD_ILLEGAL_PARAMETER;
         SSLerr(SSL_F_TLS_PARSE_STOC_KEY_SHARE, SSL_R_BAD_ECPOINT);
         EVP_PKEY_free(skey);
         return 0;
@@ -1434,12 +1698,13 @@ int tls_parse_stoc_early_data(SSL *s, PACKET *pkt, unsigned int context,
         return 0;
     }
 
-    if (s->ext.early_data != SSL_EARLY_DATA_REJECTED
+    if (!s->ext.early_data_ok
             || !s->hit
             || s->session->ext.tick_identity != 0) {
         /*
          * If we get here then we didn't send early data, or we didn't resume
-         * using the first identity so the server should not be accepting it.
+         * using the first identity, or the SNI/ALPN is not consistent so the
+         * server should not be accepting it.
          */
         *al = SSL_AD_ILLEGAL_PARAMETER;
         return 0;
@@ -1457,17 +1722,39 @@ int tls_parse_stoc_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     unsigned int identity;
 
     if (!PACKET_get_net_2(pkt, &identity) || PACKET_remaining(pkt) != 0) {
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PARSE_STOC_PSK, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
 
-    if (s->session->ext.tick_identity != (int)identity) {
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+    if (s->session->ext.tick_identity == (int)identity) {
+        s->hit = 1;
+        SSL_SESSION_free(s->psksession);
+        s->psksession = NULL;
+        return 1;
+    }
+
+    if (s->psksession == NULL
+            || s->psksession->ext.tick_identity != (int)identity) {
+        *al = SSL_AD_ILLEGAL_PARAMETER;
         SSLerr(SSL_F_TLS_PARSE_STOC_PSK, SSL_R_BAD_PSK_IDENTITY);
         return 0;
     }
 
+    /*
+     * If we used the external PSK for sending early_data then s->early_secret
+     * is already set up, so don't overwrite it. Otherwise we copy the
+     * early_secret across that we generated earlier.
+     */
+    if ((s->early_data_state != SSL_EARLY_DATA_WRITE_RETRY
+                && s->early_data_state != SSL_EARLY_DATA_FINISHED_WRITING)
+            || s->session->ext.max_early_data > 0
+            || s->psksession->ext.max_early_data == 0)
+        memcpy(s->early_secret, s->psksession->early_secret, EVP_MAX_MD_SIZE);
+
+    SSL_SESSION_free(s->session);
+    s->session = s->psksession;
+    s->psksession = NULL;
     s->hit = 1;
 #endif