Enable the ability to use an external PSK for sending early_data
[openssl.git] / ssl / statem / extensions_srvr.c
index 22d2c4af2d52d037c797212c98e8f5ca834546d4..2363c426e047b07b7d643e7a5d695432e319cd16 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
@@ -25,7 +25,7 @@ int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, unsigned int context,
         || !PACKET_get_bytes(pkt, &data, ilen)) {
         SSLerr(SSL_F_TLS_PARSE_CTOS_RENEGOTIATE,
                SSL_R_RENEGOTIATION_ENCODING_ERR);
-        *al = SSL_AD_ILLEGAL_PARAMETER;
+        *al = SSL_AD_DECODE_ERROR;
         return 0;
     }
 
@@ -87,10 +87,9 @@ int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, unsigned int context,
     }
 
     /*
-     * Although the server_name extension was intended to be
-     * extensible to new name types, RFC 4366 defined the
-     * syntax inextensibly and OpenSSL 1.0.x parses it as
-     * such.
+     * Although the intent was for server_name to be extensible, RFC 4366
+     * was not clear about it; and so OpenSSL among other implementations,
+     * always and only allows a 'host_name' name types.
      * RFC 6066 corrected the mistake but adding new name types
      * is nevertheless no longer feasible, so act as if no other
      * SNI types can exist, to simplify parsing.
@@ -154,7 +153,7 @@ int tls_parse_ctos_srp(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
      * upon resumption. Instead, we MUST ignore the login.
      */
     if (!PACKET_strndup(&srp_I, &s->srp_ctx.login)) {
-        *al = TLS1_AD_INTERNAL_ERROR;
+        *al = SSL_AD_INTERNAL_ERROR;
         return 0;
     }
 
@@ -178,7 +177,7 @@ int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, unsigned int context,
         if (!PACKET_memdup(&ec_point_format_list,
                            &s->session->ext.ecpointformats,
                            &s->session->ext.ecpointformats_len)) {
-            *al = TLS1_AD_INTERNAL_ERROR;
+            *al = SSL_AD_INTERNAL_ERROR;
             return 0;
         }
     }
@@ -194,7 +193,7 @@ int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, unsigned int context,
             !s->ext.session_ticket_cb(s, PACKET_data(pkt),
                                   PACKET_remaining(pkt),
                                   s->ext.session_ticket_cb_arg)) {
-        *al = TLS1_AD_INTERNAL_ERROR;
+        *al = SSL_AD_INTERNAL_ERROR;
         return 0;
     }
 
@@ -213,7 +212,7 @@ int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     }
 
     if (!s->hit && !tls1_save_sigalgs(s, &supported_sig_algs)) {
-        *al = TLS1_AD_DECODE_ERROR;
+        *al = SSL_AD_DECODE_ERROR;
         return 0;
     }
 
@@ -368,7 +367,7 @@ int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     s->s3->alpn_proposed_len = 0;
     if (!PACKET_memdup(&save_protocol_list,
                        &s->s3->alpn_proposed, &s->s3->alpn_proposed_len)) {
-        *al = TLS1_AD_INTERNAL_ERROR;
+        *al = SSL_AD_INTERNAL_ERROR;
         return 0;
     }
 
@@ -477,7 +476,8 @@ int tls_parse_ctos_psk_kex_modes(SSL *s, PACKET *pkt, unsigned int context,
     while (PACKET_get_1(&psk_kex_modes, &mode)) {
         if (mode == TLSEXT_KEX_MODE_KE_DHE)
             s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE_DHE;
-        else if (mode == TLSEXT_KEX_MODE_KE)
+        else if (mode == TLSEXT_KEX_MODE_KE
+                && (s->options & SSL_OP_ALLOW_NO_DHE_KEX) != 0)
             s->ext.psk_kex_mode |= TLSEXT_KEX_MODE_FLAG_KE;
     }
 #endif
@@ -512,7 +512,7 @@ int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     }
 
     if (!PACKET_as_length_prefixed_2(pkt, &key_share_list)) {
-        *al = SSL_AD_HANDSHAKE_FAILURE;
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_LENGTH_MISMATCH);
         return 0;
     }
@@ -524,22 +524,29 @@ int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
         return 0;
     }
 
-    /*
-     * Get the clients list of supported curves.
-     * TODO(TLS1.3): We should validate that we actually received
-     * supported_groups!
-     */
+    /* Get the clients list of supported curves. */
     if (!tls1_get_curvelist(s, 1, &clntcurves, &clnt_num_curves)) {
         *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE, ERR_R_INTERNAL_ERROR);
         return 0;
     }
+    if (clnt_num_curves == 0) {
+        /*
+         * This can only happen if the supported_groups extension was not sent,
+         * because we verify that the length is non-zero when we process that
+         * extension.
+         */
+        *al = SSL_AD_MISSING_EXTENSION;
+        SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
+               SSL_R_MISSING_SUPPORTED_GROUPS_EXTENSION);
+        return 0;
+    }
 
     while (PACKET_remaining(&key_share_list) > 0) {
         if (!PACKET_get_net_2(&key_share_list, &group_id)
                 || !PACKET_get_length_prefixed_2(&key_share_list, &encoded_pt)
                 || PACKET_remaining(&encoded_pt) == 0) {
-            *al = SSL_AD_HANDSHAKE_FAILURE;
+            *al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE,
                    SSL_R_LENGTH_MISMATCH);
             return 0;
@@ -554,7 +561,7 @@ int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
 
         /* Check if this share is in supported_groups sent from client */
         if (!check_in_list(s, group_id, clntcurves, clnt_num_curves, 0)) {
-            *al = SSL_AD_HANDSHAKE_FAILURE;
+            *al = SSL_AD_ILLEGAL_PARAMETER;
             SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_KEY_SHARE);
             return 0;
         }
@@ -607,7 +614,7 @@ int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
         if (!EVP_PKEY_set1_tls_encodedpoint(s->s3->peer_tmp,
                 PACKET_data(&encoded_pt),
                 PACKET_remaining(&encoded_pt))) {
-            *al = SSL_AD_DECODE_ERROR;
+            *al = SSL_AD_ILLEGAL_PARAMETER;
             SSLerr(SSL_F_TLS_PARSE_CTOS_KEY_SHARE, SSL_R_BAD_ECPOINT);
             return 0;
         }
@@ -633,14 +640,16 @@ int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, unsigned int context,
         return 0;
     }
 
-    OPENSSL_free(s->session->ext.supportedgroups);
-    s->session->ext.supportedgroups = NULL;
-    s->session->ext.supportedgroups_len = 0;
-    if (!PACKET_memdup(&supported_groups_list,
-                       &s->session->ext.supportedgroups,
-                       &s->session->ext.supportedgroups_len)) {
-        *al = SSL_AD_DECODE_ERROR;
-        return 0;
+    if (!s->hit || SSL_IS_TLS13(s)) {
+        OPENSSL_free(s->session->ext.supportedgroups);
+        s->session->ext.supportedgroups = NULL;
+        s->session->ext.supportedgroups_len = 0;
+        if (!PACKET_memdup(&supported_groups_list,
+                           &s->session->ext.supportedgroups,
+                           &s->session->ext.supportedgroups_len)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
     }
 
     return 1;
@@ -670,6 +679,11 @@ int tls_parse_ctos_early_data(SSL *s, PACKET *pkt, unsigned int context,
         return 0;
     }
 
+    if (s->hello_retry_request) {
+        *al = SSL_AD_ILLEGAL_PARAMETER;
+        return 0;
+    }
+
     return 1;
 }
 
@@ -679,9 +693,8 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     PACKET identities, binders, binder;
     size_t binderoffset, hashsize;
     SSL_SESSION *sess = NULL;
-    unsigned int id, i;
+    unsigned int id, i, ext = 0;
     const EVP_MD *md = NULL;
-    uint32_t ticket_age = 0, now, agesec, agems;
 
     /*
      * If we have no PSK kex mode that we recognise then we can't resume so
@@ -699,7 +712,6 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
     for (id = 0; PACKET_remaining(&identities) != 0; id++) {
         PACKET identity;
         unsigned long ticket_agel;
-        int ret;
 
         if (!PACKET_get_length_prefixed_2(&identities, &identity)
                 || !PACKET_get_net_4(&identities, &ticket_agel)) {
@@ -707,33 +719,80 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
             return 0;
         }
 
-        ticket_age = (uint32_t)ticket_agel;
-
-        ret = tls_decrypt_ticket(s, PACKET_data(&identity),
-                                 PACKET_remaining(&identity), NULL, 0, &sess);
-        if (ret == TICKET_FATAL_ERR_MALLOC || ret == TICKET_FATAL_ERR_OTHER) {
+        if (s->psk_find_session_cb != NULL
+                && !s->psk_find_session_cb(s, PACKET_data(&identity),
+                                           PACKET_remaining(&identity),
+                                           &sess)) {
             *al = SSL_AD_INTERNAL_ERROR;
             return 0;
         }
-        if (ret == TICKET_NO_DECRYPT)
-            continue;
 
-        md = ssl_md(sess->cipher->algorithm2);
-        if (md == NULL) {
+        if (sess != NULL) {
+            /* We found a PSK */
+            SSL_SESSION *sesstmp = ssl_session_dup(sess, 0);
+
+            if (sesstmp == NULL) {
+                *al = SSL_AD_INTERNAL_ERROR;
+                return 0;
+            }
+            SSL_SESSION_free(sess);
+            sess = sesstmp;
+
             /*
-             * Don't recognise this cipher so we can't use the session.
-             * Ignore it
+             * We've just been told to use this session for this context so
+             * make sure the sid_ctx matches up.
              */
+            memcpy(sess->sid_ctx, s->sid_ctx, s->sid_ctx_length);
+            sess->sid_ctx_length = s->sid_ctx_length;
+            ext = 1;
+            s->ext.early_data_ok = 1;
+        } else {
+            uint32_t ticket_age = 0, now, agesec, agems;
+            int ret = tls_decrypt_ticket(s, PACKET_data(&identity),
+                                         PACKET_remaining(&identity), NULL, 0,
+                                         &sess);
+
+            if (ret == TICKET_FATAL_ERR_MALLOC
+                    || ret == TICKET_FATAL_ERR_OTHER) {
+                *al = SSL_AD_INTERNAL_ERROR;
+                return 0;
+            }
+            if (ret == TICKET_NO_DECRYPT)
+                continue;
+
+            ticket_age = (uint32_t)ticket_agel;
+            now = (uint32_t)time(NULL);
+            agesec = now - (uint32_t)sess->time;
+            agems = agesec * (uint32_t)1000;
+            ticket_age -= sess->ext.tick_age_add;
+
+            /*
+             * For simplicity we do our age calculations in seconds. If the
+             * client does it in ms then it could appear that their ticket age
+             * is longer than ours (our ticket age calculation should always be
+             * slightly longer than the client's due to the network latency).
+             * Therefore we add 1000ms to our age calculation to adjust for
+             * rounding errors.
+             */
+            if (sess->timeout >= (long)agesec
+                    && agems / (uint32_t)1000 == agesec
+                    && ticket_age <= agems + 1000
+                    && ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
+                /*
+                 * Ticket age is within tolerance and not expired. We allow it
+                 * for early data
+                 */
+                s->ext.early_data_ok = 1;
+            }
+        }
+
+        md = ssl_md(sess->cipher->algorithm2);
+        if (md != ssl_md(s->s3->tmp.new_cipher->algorithm2)) {
+            /* The ciphersuite is not compatible with this session. */
             SSL_SESSION_free(sess);
             sess = NULL;
             continue;
         }
-
-        /*
-         * TODO(TLS1.3): Somehow we need to handle the case of a ticket renewal.
-         * Ignored for now
-         */
-
         break;
     }
 
@@ -759,7 +818,7 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
             || tls_psk_do_binder(s, md,
                                  (const unsigned char *)s->init_buf->data,
                                  binderoffset, PACKET_data(&binder), NULL,
-                                 sess, 0) != 1) {
+                                 sess, 0, ext) != 1) {
         *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PARSE_CTOS_PSK, ERR_R_INTERNAL_ERROR);
         goto err;
@@ -767,31 +826,6 @@ int tls_parse_ctos_psk(SSL *s, PACKET *pkt, unsigned int context, X509 *x,
 
     sess->ext.tick_identity = id;
 
-    now = (uint32_t)time(NULL);
-    agesec = now - (uint32_t)sess->time;
-    agems = agesec * (uint32_t)1000;
-    ticket_age -= sess->ext.tick_age_add;
-
-
-    /*
-     * For simplicity we do our age calculations in seconds. If the client does
-     * it in ms then it could appear that their ticket age is longer than ours
-     * (our ticket age calculation should always be slightly longer than the
-     * client's due to the network latency). Therefore we add 1000ms to our age
-     * calculation to adjust for rounding errors.
-     */
-    if (sess->timeout >= (long)agesec
-            && agems / (uint32_t)1000 == agesec
-            && ticket_age <= agems + 1000
-            && ticket_age + TICKET_AGE_ALLOWANCE >= agems + 1000) {
-        /*
-         * Ticket age is within tolerance and not expired. We allow it for early
-         * data
-         */
-        s->ext.early_data_ok = 1;
-    }
-
-
     SSL_SESSION_free(s->session);
     s->session = sess;
     return 1;
@@ -803,12 +837,14 @@ err:
 /*
  * Add the server's renegotiation binding
  */
-int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, unsigned int context,
-                                   X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx, int *al)
 {
     if (!s->s3->send_connection_binding)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
+    /* Still add this even if SSL_OP_NO_RENEGOTIATION is set */
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_renegotiate)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_start_sub_packet_u8(pkt)
@@ -819,31 +855,33 @@ int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_RENEGOTIATE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, unsigned int context,
-                                   X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_server_name(SSL *s, WPACKET *pkt,
+                                          unsigned int context, X509 *x,
+                                          size_t chainidx, int *al)
 {
     if (s->hit || s->servername_done != 1
             || s->session->ext.hostname == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_server_name)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SERVER_NAME, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_EC
-int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, unsigned int context,
-                                     X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx, int *al)
 {
     unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
     unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@@ -853,7 +891,7 @@ int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, unsigned int context,
     size_t plistlen;
 
     if (!using_ecc)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     tls1_get_formatlist(s, &plist, &plistlen);
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_ec_point_formats)
@@ -861,28 +899,29 @@ int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_sub_memcpy_u8(pkt, plist, plistlen)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_EC_PT_FORMATS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
-                                        unsigned int context, X509 *x,
-                                        size_t chainidx, int *al)
+#ifndef OPENSSL_NO_EC
+EXT_RETURN tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
+                                               unsigned int context, X509 *x,
+                                               size_t chainidx, int *al)
 {
     const unsigned char *groups;
     size_t numgroups, i, first = 1;
 
     /* s->s3->group_id is non zero if we accepted a key_share */
     if (s->s3->group_id == 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /* Get our list of supported groups */
     if (!tls1_get_curvelist(s, 0, &groups, &numgroups) || numgroups == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /* Copy group ID if supported */
@@ -894,7 +933,7 @@ int tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
                  * so we don't need to add this extension
                  */
                 if (s->s3->group_id == GET_GROUP_ID(groups, 0))
-                    return 1;
+                    return EXT_RETURN_NOT_SENT;
 
                 /* Add extension header */
                 if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_supported_groups)
@@ -903,7 +942,7 @@ int tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
                         || !WPACKET_start_sub_packet_u16(pkt)) {
                     SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
                            ERR_R_INTERNAL_ERROR);
-                    return 0;
+                    return EXT_RETURN_FAIL;
                 }
 
                 first = 0;
@@ -911,52 +950,53 @@ int tls_construct_stoc_supported_groups(SSL *s, WPACKET *pkt,
             if (!WPACKET_put_bytes_u16(pkt, GET_GROUP_ID(groups, 0))) {
                     SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS,
                            ERR_R_INTERNAL_ERROR);
-                    return 0;
+                    return EXT_RETURN_FAIL;
                 }
         }
     }
 
     if (!WPACKET_close(pkt) || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SUPPORTED_GROUPS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
+#endif
 
-int tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt,
-                                      unsigned int context, X509 *x,
-                                      size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
 {
     if (!s->ext.ticket_expected || !tls_use_ticket(s)) {
         s->ext.ticket_expected = 0;
-        return 1;
+        return EXT_RETURN_NOT_SENT;
     }
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_session_ticket)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_SESSION_TICKET, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_OCSP
-int tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
-                                      unsigned int context, X509 *x,
-                                      size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
 {
     if (!s->ext.status_expected)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (SSL_IS_TLS13(s) && chainidx != 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
             || !WPACKET_start_sub_packet_u16(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_STATUS_REQUEST, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /*
@@ -967,17 +1007,17 @@ int tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
     if ((SSL_IS_TLS13(s) && !tls_construct_cert_status_body(s, pkt))
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_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_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
-                                      unsigned int context, X509 *x,
-                                      size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
+                                             unsigned int context, X509 *x,
+                                             size_t chainidx, int *al)
 {
     const unsigned char *npa;
     unsigned int npalen;
@@ -986,7 +1026,7 @@ int tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
 
     s->s3->npn_seen = 0;
     if (!npn_seen || s->ctx->ext.npn_advertised_cb == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     ret = s->ctx->ext.npn_advertised_cb(s, &npa, &npalen,
                                         s->ctx->ext.npn_advertised_cb_arg);
@@ -995,20 +1035,20 @@ int tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt,
                 || !WPACKET_sub_memcpy_u16(pkt, npa, npalen)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_STOC_NEXT_PROTO_NEG,
                    ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
         s->s3->npn_seen = 1;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                            size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, unsigned int context,
+                                   X509 *x, size_t chainidx, int *al)
 {
     if (s->s3->alpn_selected == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt,
                 TLSEXT_TYPE_application_layer_protocol_negotiation)
@@ -1019,18 +1059,19 @@ int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
             || !WPACKET_close(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_ALPN, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
 #ifndef OPENSSL_NO_SRTP
-int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
-                                X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt,
+                                       unsigned int context, X509 *x,
+                                       size_t chainidx, int *al)
 {
     if (s->srtp_profile == NULL)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_use_srtp)
             || !WPACKET_start_sub_packet_u16(pkt)
@@ -1039,18 +1080,18 @@ int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, unsigned int context,
             || !WPACKET_put_bytes_u8(pkt, 0)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_USE_SRTP, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 #endif
 
-int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_etm(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (!s->ext.use_etm)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     /*
      * Don't use encrypt_then_mac if AEAD or RC4 might want to disable
@@ -1061,35 +1102,36 @@ int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
         || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT
         || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT12) {
         s->ext.use_etm = 0;
-        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_STOC_ETM, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_ems(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if ((s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) == 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_EMS, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, unsigned int context,
-                                 X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_key_share(SSL *s, WPACKET *pkt,
+                                        unsigned int context, X509 *x,
+                                        size_t chainidx, int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
     unsigned char *encodedPoint;
@@ -1105,32 +1147,32 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, unsigned int context,
                     || !WPACKET_close(pkt)) {
                 SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE,
                        ERR_R_INTERNAL_ERROR);
-                return 0;
+                return EXT_RETURN_FAIL;
             }
 
-            return 1;
+            return EXT_RETURN_SENT;
         }
 
         /* Must be resuming. */
         if (!s->hit || !tls13_generate_handshake_secret(s, NULL, 0)) {
             *al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
-        return 1;
+        return EXT_RETURN_NOT_SENT;
     }
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_key_share)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_put_bytes_u16(pkt, s->s3->group_id)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     skey = ssl_generate_pkey(ckey);
     if (skey == NULL) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_MALLOC_FAILURE);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     /* Generate encoding of server key */
@@ -1138,7 +1180,7 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, unsigned int context,
     if (encoded_pt_len == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_EC_LIB);
         EVP_PKEY_free(skey);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
     if (!WPACKET_sub_memcpy_u16(pkt, encodedPoint, encoded_pt_len)
@@ -1146,7 +1188,7 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, unsigned int context,
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
         EVP_PKEY_free(skey);
         OPENSSL_free(encodedPoint);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
     OPENSSL_free(encodedPoint);
 
@@ -1154,15 +1196,16 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, unsigned int context,
     s->s3->tmp.pkey = skey;
     if (ssl_derive(s, skey, ckey, 1) == 0) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_KEY_SHARE, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 #endif
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt, unsigned int context,
-                                     X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt,
+                                            unsigned int context, X509 *x,
+                                            size_t chainidx, int *al)
 {
     const unsigned char cryptopro_ext[36] = {
         0xfd, 0xe8,         /* 65000 */
@@ -1176,60 +1219,61 @@ int tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt, unsigned int context,
     if (((s->s3->tmp.new_cipher->id & 0xFFFF) != 0x80
          && (s->s3->tmp.new_cipher->id & 0xFFFF) != 0x81)
             || (SSL_get_options(s) & SSL_OP_CRYPTOPRO_TLSEXT_BUG) == 0)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_memcpy(pkt, cryptopro_ext, sizeof(cryptopro_ext))) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_CRYPTOPRO_BUG, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_early_data(SSL *s, WPACKET *pkt, unsigned int context,
-                                  X509 *x, size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_early_data(SSL *s, WPACKET *pkt,
+                                         unsigned int context, X509 *x,
+                                         size_t chainidx, int *al)
 {
     if (context == SSL_EXT_TLS1_3_NEW_SESSION_TICKET) {
         if (s->max_early_data == 0)
-            return 1;
+            return EXT_RETURN_NOT_SENT;
 
         if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
                 || !WPACKET_start_sub_packet_u16(pkt)
                 || !WPACKET_put_bytes_u32(pkt, s->max_early_data)
                 || !WPACKET_close(pkt)) {
             SSLerr(SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return EXT_RETURN_FAIL;
         }
 
-        return 1;
+        return EXT_RETURN_SENT;
     }
 
     if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_early_data)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_EARLY_DATA, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }
 
-int tls_construct_stoc_psk(SSL *s, WPACKET *pkt, unsigned int context, X509 *x,
-                           size_t chainidx, int *al)
+EXT_RETURN tls_construct_stoc_psk(SSL *s, WPACKET *pkt, unsigned int context,
+                                  X509 *x, size_t chainidx, int *al)
 {
     if (!s->hit)
-        return 1;
+        return EXT_RETURN_NOT_SENT;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_psk)
             || !WPACKET_start_sub_packet_u16(pkt)
             || !WPACKET_put_bytes_u16(pkt, s->session->ext.tick_identity)
             || !WPACKET_close(pkt)) {
         SSLerr(SSL_F_TLS_CONSTRUCT_STOC_PSK, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return EXT_RETURN_FAIL;
     }
 
-    return 1;
+    return EXT_RETURN_SENT;
 }