From: Matt Caswell <matt@openssl.org>
Date: Fri, 12 Aug 2022 12:27:21 +0000 (+0100)
Subject: Use an enum for the return value from a construction function
X-Git-Tag: openssl-3.2.0-alpha1~2064
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=67ec6d2b747810db609330003dcf08c8c584105b;p=thirdparty%2Fopenssl.git

Use an enum for the return value from a construction function

Construction return values are no longer boolean but can return 3 different
values, so we use an enum to represent them.

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18990)
---

diff --git a/ssl/statem/statem.c b/ssl/statem/statem.c
index ad227d2a9fd..b885214f3c2 100644
--- a/ssl/statem/statem.c
+++ b/ssl/statem/statem.c
@@ -806,11 +806,11 @@ static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s)
     WORK_STATE(*pre_work) (SSL_CONNECTION *s, WORK_STATE wst);
     WORK_STATE(*post_work) (SSL_CONNECTION *s, WORK_STATE wst);
     int (*get_construct_message_f) (SSL_CONNECTION *s,
-                                    int (**confunc) (SSL_CONNECTION *s,
-                                                     WPACKET *pkt),
+                                    CON_FUNC_RETURN (**confunc) (SSL_CONNECTION *s,
+                                                                 WPACKET *pkt),
                                     int *mt);
     void (*cb) (const SSL *ssl, int type, int val) = NULL;
-    int (*confunc) (SSL_CONNECTION *s, WPACKET *pkt);
+    CON_FUNC_RETURN (*confunc) (SSL_CONNECTION *s, WPACKET *pkt);
     int mt;
     WPACKET pkt;
     SSL *ssl = SSL_CONNECTION_GET_SSL(s);
@@ -889,14 +889,14 @@ static SUB_STATE_RETURN write_state_machine(SSL_CONNECTION *s)
                 return SUB_STATE_ERROR;
             }
             if (confunc != NULL) {
-                int tmpret;
+                CON_FUNC_RETURN tmpret;
 
                 tmpret = confunc(s, &pkt);
-                if (tmpret <= 0) {
+                if (tmpret == CON_FUNC_ERROR) {
                     WPACKET_cleanup(&pkt);
                     check_fatal(s);
                     return SUB_STATE_ERROR;
-                } else if (tmpret == 2) {
+                } else if (tmpret == CON_FUNC_DONT_SEND) {
                     /*
                      * The construction function decided not to construct the
                      * message after all and continue. Skip sending.
diff --git a/ssl/statem/statem.h b/ssl/statem/statem.h
index 75fb06481c0..28ef97922e6 100644
--- a/ssl/statem/statem.h
+++ b/ssl/statem/statem.h
@@ -80,6 +80,12 @@ typedef enum {
     ENC_WRITE_STATE_WRITE_PLAIN_ALERTS
 } ENC_WRITE_STATES;
 
+typedef enum {
+    CON_FUNC_ERROR = 0,
+    CON_FUNC_SUCCESS,
+    CON_FUNC_DONT_SEND
+} CON_FUNC_RETURN;
+
 /*****************************************************************************
  *                                                                           *
  * This structure should be considered "opaque" to anything outside of the   *
diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 1bccd6b27c8..3d00386129b 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -1098,7 +1098,7 @@ WORK_STATE ossl_statem_client_post_process_message(SSL_CONNECTION *s,
     }
 }
 
-int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
 {
     unsigned char *p;
     size_t sess_id_len;
@@ -1114,7 +1114,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
     protverr = ssl_set_client_hello_version(s);
     if (protverr != 0) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, protverr);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (sess == NULL
@@ -1123,7 +1123,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
         if (s->hello_retry_request == SSL_HRR_NONE
                 && !ssl_get_new_session(s, 0)) {
             /* SSLfatal() already called */
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
     /* else use the pre-loaded session */
@@ -1150,7 +1150,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
     if (i && ssl_fill_hello_random(s, 0, p, sizeof(s->s3.client_random),
                                    DOWNGRADE_NONE) <= 0) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /*-
@@ -1189,7 +1189,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
     if (!WPACKET_put_bytes_u16(pkt, s->client_version)
             || !WPACKET_memcpy(pkt, s->s3.client_random, SSL3_RANDOM_SIZE)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /* Session ID */
@@ -1204,7 +1204,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
                     && RAND_bytes_ex(sctx->libctx, s->tmp_session_id,
                                      sess_id_len, 0) <= 0) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
         } else {
             sess_id_len = 0;
@@ -1222,7 +1222,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
                                                     sess_id_len))
             || !WPACKET_close(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /* cookie stuff for DTLS */
@@ -1231,30 +1231,30 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
                 || !WPACKET_sub_memcpy_u8(pkt, s->d1->cookie,
                                           s->d1->cookie_len)) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
 
     /* Ciphers supported */
     if (!WPACKET_start_sub_packet_u16(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (!ssl_cipher_list_to_bytes(s, SSL_get_ciphers(SSL_CONNECTION_GET_SSL(s)),
                                   pkt)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
     if (!WPACKET_close(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /* COMPRESSION */
     if (!WPACKET_start_sub_packet_u8(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 #ifndef OPENSSL_NO_COMP
     if (ssl_allow_compression(s)
@@ -1266,7 +1266,7 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
             comp = sk_SSL_COMP_value(sctx->comp_methods, i);
             if (!WPACKET_put_bytes_u8(pkt, comp->id)) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
         }
     }
@@ -1274,16 +1274,16 @@ int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt)
     /* Add the NULL method */
     if (!WPACKET_put_bytes_u8(pkt, 0) || !WPACKET_close(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /* TLS extensions */
     if (!tls_construct_extensions(s, pkt, SSL_EXT_CLIENT_HELLO, NULL, 0)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 MSG_PROCESS_RETURN dtls_process_hello_verify(SSL_CONNECTION *s, PACKET *pkt)
@@ -3315,7 +3315,8 @@ static int tls_construct_cke_srp(SSL_CONNECTION *s, WPACKET *pkt)
 #endif
 }
 
-int tls_construct_client_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_client_key_exchange(SSL_CONNECTION *s,
+                                                  WPACKET *pkt)
 {
     unsigned long alg_k;
 
@@ -3352,7 +3353,7 @@ int tls_construct_client_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
         goto err;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
  err:
     OPENSSL_clear_free(s->s3.tmp.pms, s->s3.tmp.pmslen);
     s->s3.tmp.pms = NULL;
@@ -3362,7 +3363,7 @@ int tls_construct_client_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
     s->s3.tmp.psk = NULL;
     s->s3.tmp.psklen = 0;
 #endif
-    return 0;
+    return CON_FUNC_ERROR;
 }
 
 int tls_client_key_exchange_post_work(SSL_CONNECTION *s)
@@ -3538,7 +3539,8 @@ WORK_STATE tls_prepare_client_certificate(SSL_CONNECTION *s, WORK_STATE wst)
     return WORK_ERROR;
 }
 
-int tls_construct_client_certificate(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_client_certificate(SSL_CONNECTION *s,
+                                                 WPACKET *pkt)
 {
     SSL *ssl = SSL_CONNECTION_GET_SSL(s);
 
@@ -3547,18 +3549,18 @@ int tls_construct_client_certificate(SSL_CONNECTION *s, WPACKET *pkt)
             /* no context available, add 0-length context */
             if (!WPACKET_put_bytes_u8(pkt, 0)) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
         } else if (!WPACKET_sub_memcpy_u8(pkt, s->pha_context, s->pha_context_len)) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
     if (!ssl3_output_cert_chain(s, pkt,
                                 (s->s3.tmp.cert_req == 2) ? NULL
                                                            : s->cert->key)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (SSL_CONNECTION_IS_TLS13(s)
@@ -3570,10 +3572,10 @@ int tls_construct_client_certificate(SSL_CONNECTION *s, WPACKET *pkt)
          * state and thus ssl3_send_alert may crash.
          */
         SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_CANNOT_CHANGE_CIPHER);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 int ssl3_check_cert_and_algorithm(SSL_CONNECTION *s)
@@ -3620,7 +3622,7 @@ int ssl3_check_cert_and_algorithm(SSL_CONNECTION *s)
 }
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_construct_next_proto(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_next_proto(SSL_CONNECTION *s, WPACKET *pkt)
 {
     size_t len, padding_len;
     unsigned char *padding = NULL;
@@ -3631,12 +3633,12 @@ int tls_construct_next_proto(SSL_CONNECTION *s, WPACKET *pkt)
     if (!WPACKET_sub_memcpy_u8(pkt, s->ext.npn, len)
             || !WPACKET_sub_allocate_bytes_u8(pkt, padding_len, &padding)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     memset(padding, 0, padding_len);
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 #endif
 
@@ -3820,14 +3822,14 @@ int ssl_cipher_list_to_bytes(SSL_CONNECTION *s, STACK_OF(SSL_CIPHER) *sk,
     return 1;
 }
 
-int tls_construct_end_of_early_data(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_end_of_early_data(SSL_CONNECTION *s, WPACKET *pkt)
 {
     if (s->early_data_state != SSL_EARLY_DATA_WRITE_RETRY
             && s->early_data_state != SSL_EARLY_DATA_FINISHED_WRITING) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
diff --git a/ssl/statem/statem_dtls.c b/ssl/statem/statem_dtls.c
index c9b17bb22bf..4fa70be723e 100644
--- a/ssl/statem/statem_dtls.c
+++ b/ssl/statem/statem_dtls.c
@@ -927,18 +927,19 @@ static int dtls_get_reassembled_message(SSL_CONNECTION *s, int *errtype,
  * ssl->session->read_compression       assign
  * ssl->session->read_hash              assign
  */
-int dtls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN dtls_construct_change_cipher_spec(SSL_CONNECTION *s,
+                                                  WPACKET *pkt)
 {
     if (s->version == DTLS1_BAD_VER) {
         s->d1->next_handshake_write_seq++;
 
         if (!WPACKET_put_bytes_u16(pkt, s->d1->handshake_write_seq)) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 #ifndef OPENSSL_NO_SCTP
diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c
index ea49d71de5f..bfc8c1cac9b 100644
--- a/ssl/statem/statem_lib.c
+++ b/ssl/statem/statem_lib.c
@@ -268,7 +268,7 @@ static int get_cert_verify_tbs_data(SSL_CONNECTION *s, unsigned char *tls13tbs,
     return 1;
 }
 
-int tls_construct_cert_verify(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_cert_verify(SSL_CONNECTION *s, WPACKET *pkt)
 {
     EVP_PKEY *pkey = NULL;
     const EVP_MD *md = NULL;
@@ -386,11 +386,11 @@ int tls_construct_cert_verify(SSL_CONNECTION *s, WPACKET *pkt)
 
     OPENSSL_free(sig);
     EVP_MD_CTX_free(mctx);
-    return 1;
+    return CON_FUNC_SUCCESS;
  err:
     OPENSSL_free(sig);
     EVP_MD_CTX_free(mctx);
-    return 0;
+    return CON_FUNC_ERROR;
 }
 
 MSG_PROCESS_RETURN tls_process_cert_verify(SSL_CONNECTION *s, PACKET *pkt)
@@ -561,7 +561,7 @@ MSG_PROCESS_RETURN tls_process_cert_verify(SSL_CONNECTION *s, PACKET *pkt)
     return ret;
 }
 
-int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
 {
     size_t finish_md_len;
     const char *sender;
@@ -582,7 +582,7 @@ int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
             && (!ssl->method->ssl3_enc->change_cipher_state(s,
                     SSL3_CC_HANDSHAKE | SSL3_CHANGE_CIPHER_CLIENT_WRITE))) {;
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (s->server) {
@@ -598,14 +598,14 @@ int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
                                                             s->s3.tmp.finish_md);
     if (finish_md_len == 0) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     s->s3.tmp.finish_md_len = finish_md_len;
 
     if (!WPACKET_memcpy(pkt, s->s3.tmp.finish_md, finish_md_len)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /*
@@ -616,7 +616,7 @@ int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
         && !ssl_log_secret(s, MASTER_SECRET_LABEL, s->session->master_key,
                            s->session->master_key_length)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /*
@@ -624,7 +624,7 @@ int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
      */
     if (!ossl_assert(finish_md_len <= EVP_MAX_MD_SIZE)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
     if (!s->server) {
         memcpy(s->s3.previous_client_finished, s->s3.tmp.finish_md,
@@ -636,18 +636,18 @@ int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt)
         s->s3.previous_server_finished_len = finish_md_len;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
-int tls_construct_key_update(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_key_update(SSL_CONNECTION *s, WPACKET *pkt)
 {
     if (!WPACKET_put_bytes_u8(pkt, s->key_update)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     s->key_update = SSL_KEY_UPDATE_NONE;
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 MSG_PROCESS_RETURN tls_process_key_update(SSL_CONNECTION *s, PACKET *pkt)
@@ -896,14 +896,14 @@ MSG_PROCESS_RETURN tls_process_finished(SSL_CONNECTION *s, PACKET *pkt)
     return MSG_PROCESS_FINISHED_READING;
 }
 
-int tls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt)
 {
     if (!WPACKET_put_bytes_u8(pkt, SSL3_MT_CCS)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 /* Add a certificate to the WPACKET */
diff --git a/ssl/statem/statem_local.h b/ssl/statem/statem_local.h
index 22b6ddb584d..be28c930b8b 100644
--- a/ssl/statem/statem_local.h
+++ b/ssl/statem/statem_local.h
@@ -54,7 +54,7 @@ typedef enum {
     MSG_PROCESS_CONTINUE_READING
 } MSG_PROCESS_RETURN;
 
-typedef int (*confunc_f) (SSL_CONNECTION *s, WPACKET *pkt);
+typedef CON_FUNC_RETURN (*confunc_f) (SSL_CONNECTION *s, WPACKET *pkt);
 
 int ssl3_take_mac(SSL_CONNECTION *s);
 int check_in_list(SSL_CONNECTION *s, uint16_t group_id, const uint16_t *groups,
@@ -111,11 +111,13 @@ __owur int tls_process_initial_server_flight(SSL_CONNECTION *s);
 __owur MSG_PROCESS_RETURN tls_process_change_cipher_spec(SSL_CONNECTION *s,
                                                          PACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_finished(SSL_CONNECTION *s, PACKET *pkt);
-__owur int tls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int dtls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN  tls_construct_change_cipher_spec(SSL_CONNECTION *s,
+                                                         WPACKET *pkt);
+__owur CON_FUNC_RETURN dtls_construct_change_cipher_spec(SSL_CONNECTION *s,
+                                                         WPACKET *pkt);
 
-__owur int tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_key_update(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_finished(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_key_update(SSL_CONNECTION *s, WPACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_key_update(SSL_CONNECTION *s,
                                                  PACKET *pkt);
 __owur WORK_STATE tls_finish_handshake(SSL_CONNECTION *s, WORK_STATE wst,
@@ -123,7 +125,8 @@ __owur WORK_STATE tls_finish_handshake(SSL_CONNECTION *s, WORK_STATE wst,
 __owur WORK_STATE dtls_wait_for_dry(SSL_CONNECTION *s);
 
 /* some client-only functions */
-__owur int tls_construct_client_hello(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_client_hello(SSL_CONNECTION *s,
+                                                  WPACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_server_hello(SSL_CONNECTION *s,
                                                    PACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_certificate_request(SSL_CONNECTION *s,
@@ -135,16 +138,20 @@ __owur MSG_PROCESS_RETURN tls_process_cert_status(SSL_CONNECTION *s,
                                                   PACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_server_done(SSL_CONNECTION *s,
                                                   PACKET *pkt);
-__owur int tls_construct_cert_verify(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_cert_verify(SSL_CONNECTION *s,
+                                                 WPACKET *pkt);
 __owur WORK_STATE tls_prepare_client_certificate(SSL_CONNECTION *s,
                                                  WORK_STATE wst);
-__owur int tls_construct_client_certificate(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_client_certificate(SSL_CONNECTION *s,
+                                                        WPACKET *pkt);
 __owur int ssl_do_client_cert_cb(SSL_CONNECTION *s, X509 **px509,
                                  EVP_PKEY **ppkey);
-__owur int tls_construct_client_key_exchange(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_client_key_exchange(SSL_CONNECTION *s,
+                                                         WPACKET *pkt);
 __owur int tls_client_key_exchange_post_work(SSL_CONNECTION *s);
 __owur int tls_construct_cert_status_body(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_cert_status(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_cert_status(SSL_CONNECTION *s,
+                                                 WPACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_key_exchange(SSL_CONNECTION *s,
                                                    PACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_server_certificate(SSL_CONNECTION *s,
@@ -153,23 +160,30 @@ __owur WORK_STATE tls_post_process_server_certificate(SSL_CONNECTION *s,
                                                       WORK_STATE wst);
 __owur int ssl3_check_cert_and_algorithm(SSL_CONNECTION *s);
 #ifndef OPENSSL_NO_NEXTPROTONEG
-__owur int tls_construct_next_proto(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_next_proto(SSL_CONNECTION *s, WPACKET *pkt);
 #endif
 __owur MSG_PROCESS_RETURN tls_process_hello_req(SSL_CONNECTION *s, PACKET *pkt);
 __owur MSG_PROCESS_RETURN dtls_process_hello_verify(SSL_CONNECTION *s, PACKET *pkt);
-__owur int tls_construct_end_of_early_data(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_end_of_early_data(SSL_CONNECTION *s,
+                                                       WPACKET *pkt);
 
 /* some server-only functions */
 __owur MSG_PROCESS_RETURN tls_process_client_hello(SSL_CONNECTION *s,
                                                    PACKET *pkt);
 __owur WORK_STATE tls_post_process_client_hello(SSL_CONNECTION *s,
                                                 WORK_STATE wst);
-__owur int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int dtls_construct_hello_verify_request(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_server_certificate(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_server_key_exchange(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt);
-__owur int tls_construct_server_done(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_server_hello(SSL_CONNECTION *s,
+                                                  WPACKET *pkt);
+__owur CON_FUNC_RETURN dtls_construct_hello_verify_request(SSL_CONNECTION *s,
+                                                           WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_server_certificate(SSL_CONNECTION *s,
+                                                        WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_server_key_exchange(SSL_CONNECTION *s,
+                                                         WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_certificate_request(SSL_CONNECTION *s,
+                                                         WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_server_done(SSL_CONNECTION *s,
+                                                 WPACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_client_certificate(SSL_CONNECTION *s,
                                                          PACKET *pkt);
 __owur MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL_CONNECTION *s,
@@ -182,7 +196,8 @@ __owur MSG_PROCESS_RETURN tls_process_cert_verify(SSL_CONNECTION *s,
 __owur MSG_PROCESS_RETURN tls_process_next_proto(SSL_CONNECTION *s,
                                                  PACKET *pkt);
 #endif
-__owur int tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt);
+__owur CON_FUNC_RETURN tls_construct_new_session_ticket(SSL_CONNECTION *s,
+                                                        WPACKET *pkt);
 MSG_PROCESS_RETURN tls_process_end_of_early_data(SSL_CONNECTION *s,
                                                  PACKET *pkt);
 
diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index cafc18ef547..e56ccfd5536 100644
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -43,7 +43,8 @@ ASN1_SEQUENCE(GOST_KX_MESSAGE) = {
 
 IMPLEMENT_ASN1_FUNCTIONS(GOST_KX_MESSAGE)
 
-static int tls_construct_encrypted_extensions(SSL_CONNECTION *s, WPACKET *pkt);
+static CON_FUNC_RETURN tls_construct_encrypted_extensions(SSL_CONNECTION *s,
+                                                          WPACKET *pkt);
 
 /*
  * ossl_statem_server13_read_transition() encapsulates the logic for the allowed
@@ -1291,7 +1292,8 @@ int dtls_raw_hello_verify_request(WPACKET *pkt, unsigned char *cookie,
     return 1;
 }
 
-int dtls_construct_hello_verify_request(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN dtls_construct_hello_verify_request(SSL_CONNECTION *s,
+                                                    WPACKET *pkt)
 {
     unsigned int cookie_leni;
     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
@@ -1301,17 +1303,17 @@ int dtls_construct_hello_verify_request(SSL_CONNECTION *s, WPACKET *pkt)
                                    &cookie_leni) == 0
         || cookie_leni > DTLS1_COOKIE_LENGTH) {
         SSLfatal(s, SSL_AD_NO_ALERT, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
-        return 0;
+        return CON_FUNC_ERROR;
     }
     s->d1->cookie_len = cookie_leni;
 
     if (!dtls_raw_hello_verify_request(pkt, s->d1->cookie,
                                        s->d1->cookie_len)) {
         SSLfatal(s, SSL_AD_NO_ALERT, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 /*-
@@ -2318,7 +2320,7 @@ WORK_STATE tls_post_process_client_hello(SSL_CONNECTION *s, WORK_STATE wst)
     return WORK_ERROR;
 }
 
-int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
 {
     int compm;
     size_t sl, len;
@@ -2338,7 +2340,7 @@ int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
                                    ? hrrrandom : s->s3.server_random,
                                SSL3_RANDOM_SIZE)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /*-
@@ -2374,7 +2376,7 @@ int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
 
     if (sl > sizeof(s->session->session_id)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /* set up the compression method */
@@ -2392,7 +2394,7 @@ int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
                                                                       pkt, &len)
             || !WPACKET_put_bytes_u8(pkt, compm)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (!tls_construct_extensions(s, pkt,
@@ -2403,7 +2405,7 @@ int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
                                           : SSL_EXT_TLS1_2_SERVER_HELLO),
                                   NULL, 0)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (s->hello_retry_request == SSL_HRR_PENDING) {
@@ -2418,29 +2420,30 @@ int tls_construct_server_hello(SSL_CONNECTION *s, WPACKET *pkt)
          */
         if (!create_synthetic_message_hash(s, NULL, 0, NULL, 0)) {
             /* SSLfatal() already called */
-            return 0;
+            return CON_FUNC_ERROR;
         }
     } else if (!(s->verify_mode & SSL_VERIFY_PEER)
                 && !ssl3_digest_cached_records(s, 0)) {
         /* SSLfatal() already called */;
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
-int tls_construct_server_done(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_server_done(SSL_CONNECTION *s, WPACKET *pkt)
 {
     if (!s->s3.tmp.cert_request) {
         if (!ssl3_digest_cached_records(s, 0)) {
             /* SSLfatal() already called */
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
-int tls_construct_server_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_server_key_exchange(SSL_CONNECTION *s,
+                                                  WPACKET *pkt)
 {
     EVP_PKEY *pkdh = NULL;
     unsigned char *encodedPoint = NULL;
@@ -2453,7 +2456,8 @@ int tls_construct_server_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
     EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();
     EVP_PKEY_CTX *pctx = NULL;
     size_t paramlen, paramoffset;
-    int freer = 0, ret = 0;
+    int freer = 0;
+    CON_FUNC_RETURN ret = CON_FUNC_ERROR;
     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
 
     if (!WPACKET_get_total_written(pkt, &paramoffset)) {
@@ -2735,7 +2739,7 @@ int tls_construct_server_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
         OPENSSL_free(tbs);
     }
 
-    ret = 1;
+    ret = CON_FUNC_SUCCESS;
  err:
     EVP_PKEY_free(pkdh);
     OPENSSL_free(encodedPoint);
@@ -2749,7 +2753,8 @@ int tls_construct_server_key_exchange(SSL_CONNECTION *s, WPACKET *pkt)
     return ret;
 }
 
-int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_certificate_request(SSL_CONNECTION *s,
+                                                  WPACKET *pkt)
 {
     if (SSL_CONNECTION_IS_TLS13(s)) {
         /* Send random context when doing post-handshake auth */
@@ -2759,24 +2764,24 @@ int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt)
             if ((s->pha_context = OPENSSL_malloc(s->pha_context_len)) == NULL) {
                 s->pha_context_len = 0;
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
             if (RAND_bytes_ex(SSL_CONNECTION_GET_CTX(s)->libctx,
                               s->pha_context, s->pha_context_len, 0) <= 0
                     || !WPACKET_sub_memcpy_u8(pkt, s->pha_context,
                                               s->pha_context_len)) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
             /* reset the handshake hash back to just after the ClientFinished */
             if (!tls13_restore_handshake_digest_for_pha(s)) {
                 /* SSLfatal() already called */
-                return 0;
+                return CON_FUNC_ERROR;
             }
         } else {
             if (!WPACKET_put_bytes_u8(pkt, 0)) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-                return 0;
+                return CON_FUNC_ERROR;
             }
         }
 
@@ -2784,7 +2789,7 @@ int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt)
                                       SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, NULL,
                                       0)) {
             /* SSLfatal() already called */
-            return 0;
+            return CON_FUNC_ERROR;
         }
         goto done;
     }
@@ -2793,7 +2798,7 @@ int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt)
     if (!WPACKET_start_sub_packet_u8(pkt)
         || !ssl3_get_req_cert_type(s, pkt) || !WPACKET_close(pkt)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     if (SSL_USE_SIGALGS(s)) {
@@ -2805,19 +2810,19 @@ int tls_construct_certificate_request(SSL_CONNECTION *s, WPACKET *pkt)
                 || !tls12_copy_sigalgs(s, pkt, psigs, nl)
                 || !WPACKET_close(pkt)) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-            return 0;
+            return CON_FUNC_ERROR;
         }
     }
 
     if (!construct_ca_names(s, get_ca_names(s), pkt)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
  done:
     s->certreqs_sent++;
     s->s3.tmp.cert_request = 1;
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 static int tls_process_cke_psk_preamble(SSL_CONNECTION *s, PACKET *pkt)
@@ -3628,13 +3633,13 @@ MSG_PROCESS_RETURN tls_process_client_certificate(SSL_CONNECTION *s,
     return ret;
 }
 
-int tls_construct_server_certificate(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_server_certificate(SSL_CONNECTION *s, WPACKET *pkt)
 {
     CERT_PKEY *cpk = s->s3.tmp.cert;
 
     if (cpk == NULL) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
     /*
@@ -3643,14 +3648,14 @@ int tls_construct_server_certificate(SSL_CONNECTION *s, WPACKET *pkt)
      */
     if (SSL_CONNECTION_IS_TLS13(s) && !WPACKET_put_bytes_u8(pkt, 0)) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
-        return 0;
+        return CON_FUNC_ERROR;
     }
     if (!ssl3_output_cert_chain(s, pkt, cpk)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 static int create_ticket_prequel(SSL_CONNECTION *s, WPACKET *pkt,
@@ -3696,13 +3701,10 @@ static int create_ticket_prequel(SSL_CONNECTION *s, WPACKET *pkt,
     return 1;
 }
 
-/*
- * Returns 1 on success, 0 to abort construction of the ticket (non-fatal), or
- * -1 on fatal error
- */
-static int construct_stateless_ticket(SSL_CONNECTION *s, WPACKET *pkt,
-                                      uint32_t age_add,
-                                      unsigned char *tick_nonce)
+static CON_FUNC_RETURN construct_stateless_ticket(SSL_CONNECTION *s,
+                                                  WPACKET *pkt,
+                                                  uint32_t age_add,
+                                                  unsigned char *tick_nonce)
 {
     unsigned char *senc = NULL;
     EVP_CIPHER_CTX *ctx = NULL;
@@ -3715,7 +3717,8 @@ static int construct_stateless_ticket(SSL_CONNECTION *s, WPACKET *pkt,
     SSL_CTX *tctx = s->session_ctx;
     unsigned char iv[EVP_MAX_IV_LENGTH];
     unsigned char key_name[TLSEXT_KEYNAME_LENGTH];
-    int iv_len, ok = -1;
+    int iv_len;
+    CON_FUNC_RETURN ok = CON_FUNC_ERROR;
     size_t macoffset, macendoffset;
     SSL *ssl = SSL_CONNECTION_GET_SSL(s);
     SSL_CTX *sctx = SSL_CONNECTION_GET_CTX(s);
@@ -3804,7 +3807,7 @@ static int construct_stateless_ticket(SSL_CONNECTION *s, WPACKET *pkt,
              * ticket
              */
             if (SSL_CONNECTION_IS_TLS13(s)) {
-                ok = 0;
+                ok = CON_FUNC_DONT_SEND;
                 goto err;
             }
             /* Put timeout and length */
@@ -3816,7 +3819,7 @@ static int construct_stateless_ticket(SSL_CONNECTION *s, WPACKET *pkt,
             OPENSSL_free(senc);
             EVP_CIPHER_CTX_free(ctx);
             ssl_hmac_free(hctx);
-            return 1;
+            return CON_FUNC_SUCCESS;
         }
         if (ret < 0) {
             SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_R_CALLBACK_FAILED);
@@ -3893,7 +3896,7 @@ static int construct_stateless_ticket(SSL_CONNECTION *s, WPACKET *pkt,
         goto err;
     }
 
-    ok = 1;
+    ok = CON_FUNC_SUCCESS;
  err:
     OPENSSL_free(senc);
     EVP_CIPHER_CTX_free(ctx);
@@ -3934,7 +3937,7 @@ static void tls_update_ticket_counts(SSL_CONNECTION *s)
         s->ext.extra_tickets_expected--;
 }
 
-int tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt)
 {
     SSL_CTX *tctx = s->session_ctx;
     unsigned char tick_nonce[TICKET_NONCE_SIZE];
@@ -3942,7 +3945,7 @@ int tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt)
         unsigned char age_add_c[sizeof(uint32_t)];
         uint32_t age_add;
     } age_add_u;
-    int ret = 0;
+    CON_FUNC_RETURN ret = CON_FUNC_ERROR;
 
     age_add_u.age_add = 0;
 
@@ -4042,13 +4045,14 @@ int tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt)
             goto err;
         }
     } else {
-        int tmpret;
+        CON_FUNC_RETURN tmpret;
 
         tmpret = construct_stateless_ticket(s, pkt, age_add_u.age_add,
                                             tick_nonce);
-        if (tmpret != 1) {
-            if (tmpret == 0) {
-                ret = 2; /* Non-fatal. Abort construction but continue */
+        if (tmpret != CON_FUNC_SUCCESS) {
+            if (tmpret == CON_FUNC_DONT_SEND) {
+                /* Non-fatal. Abort construction but continue */
+                ret = CON_FUNC_DONT_SEND;
                 /* We count this as a success so update the counts anwyay */
                 tls_update_ticket_counts(s);
             }
@@ -4068,7 +4072,7 @@ int tls_construct_new_session_ticket(SSL_CONNECTION *s, WPACKET *pkt)
         ssl_update_cache(s, SSL_SESS_CACHE_SERVER);
     }
 
-    ret = 1;
+    ret = CON_FUNC_SUCCESS;
  err:
     return ret;
 }
@@ -4089,14 +4093,14 @@ int tls_construct_cert_status_body(SSL_CONNECTION *s, WPACKET *pkt)
     return 1;
 }
 
-int tls_construct_cert_status(SSL_CONNECTION *s, WPACKET *pkt)
+CON_FUNC_RETURN tls_construct_cert_status(SSL_CONNECTION *s, WPACKET *pkt)
 {
     if (!tls_construct_cert_status_body(s, pkt)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
@@ -4135,15 +4139,16 @@ MSG_PROCESS_RETURN tls_process_next_proto(SSL_CONNECTION *s, PACKET *pkt)
 }
 #endif
 
-static int tls_construct_encrypted_extensions(SSL_CONNECTION *s, WPACKET *pkt)
+static CON_FUNC_RETURN tls_construct_encrypted_extensions(SSL_CONNECTION *s,
+                                                          WPACKET *pkt)
 {
     if (!tls_construct_extensions(s, pkt, SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS,
                                   NULL, 0)) {
         /* SSLfatal() already called */
-        return 0;
+        return CON_FUNC_ERROR;
     }
 
-    return 1;
+    return CON_FUNC_SUCCESS;
 }
 
 MSG_PROCESS_RETURN tls_process_end_of_early_data(SSL_CONNECTION *s, PACKET *pkt)