From fd4836772bd263a7b6576aab9bcd2dd140b5ac65 Mon Sep 17 00:00:00 2001
From: Marco Oliverio <marco@wolfssl.com>
Date: Mon, 4 Jul 2022 17:00:15 +0200
Subject: [PATCH] examples: support DTLS version downgrading

---
 examples/client/client.c | 36 +++++++++++++++++++++++++++++++++---
 examples/server/server.c | 11 +++++++----
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/examples/client/client.c b/examples/client/client.c
index c39e6ba1d..c88dde320 100644
--- a/examples/client/client.c
+++ b/examples/client/client.c
@@ -2802,7 +2802,7 @@ THREAD_RETURN WOLFSSL_THREAD client_test(void* args)
                 err_sys("Bad DTLS version");
 #endif /* WOLFSSL_DTLS13 */
             }
-            else
+            else if (version == 2)
                 version = -1;
         }
     }
@@ -2859,7 +2859,16 @@ THREAD_RETURN WOLFSSL_THREAD client_test(void* args)
     #endif
 
         case CLIENT_DOWNGRADE_VERSION:
-            method = wolfSSLv23_client_method_ex;
+            if (!doDTLS) {
+                method = wolfSSLv23_client_method_ex;
+            }
+            else {
+#ifdef WOLFSSL_DTLS
+                method = wolfDTLS_client_method_ex;
+#else
+                err_sys("version not supported");
+#endif /* WOLFSSL_DTLS */
+            }
             break;
     #if defined(OPENSSL_EXTRA) || defined(WOLFSSL_EITHER_SIDE)
         case EITHER_DOWNGRADE_VERSION:
@@ -2934,7 +2943,28 @@ THREAD_RETURN WOLFSSL_THREAD client_test(void* args)
     }
 #endif
     if (minVersion != CLIENT_INVALID_VERSION) {
-        wolfSSL_CTX_SetMinVersion(ctx, minVersion);
+#ifdef WOLFSSL_DTLS
+        if (doDTLS) {
+            switch (minVersion) {
+            case 4:
+#ifdef WOLFSSL_DTLS13
+                minVersion = WOLFSSL_DTLSV1_3;
+                break;
+#else
+                err_sys("invalid minimum downgrade version");
+                break;
+#endif /* WOLFSSL_DTLS13 */
+            case 3:
+                minVersion = WOLFSSL_DTLSV1_2;
+                break;
+            case 2:
+                minVersion = WOLFSSL_DTLSV1;
+                break;
+            }
+        }
+#endif /* WOLFSSL_DTLS */
+        if (wolfSSL_CTX_SetMinVersion(ctx, minVersion) != WOLFSSL_SUCCESS)
+            err_sys("can't set minimum downgrade version");
     }
     if (simulateWantWrite) {
     #ifdef USE_WOLFSSL_IO
diff --git a/examples/server/server.c b/examples/server/server.c
index 864228a99..f3ff44469 100644
--- a/examples/server/server.c
+++ b/examples/server/server.c
@@ -2265,11 +2265,11 @@ THREAD_RETURN WOLFSSL_THREAD server_test(void* args)
                 method = wolfSSLv23_server_method_ex;
             }
             else {
-#ifdef WOLFSSL_DTLS13
+#ifdef WOLFSSL_DTLS
                 method = wolfDTLS_server_method_ex;
 #else
                 err_sys_ex(runWithErrors, "version not supported");
-#endif /* WOLFSSL_DTLS13 */
+#endif /* WOLFSSL_DTLS */
             }
             break;
     #if defined(OPENSSL_EXTRA) || defined(WOLFSSL_EITHER_SIDE)
@@ -2341,12 +2341,14 @@ THREAD_RETURN WOLFSSL_THREAD server_test(void* args)
         err_sys_ex(catastrophic, "unable to get ctx");
 
     if (minVersion != SERVER_INVALID_VERSION) {
-#ifdef WOLFSSL_DTLS13
+#ifdef WOLFSSL_DTLS
         if (doDTLS) {
             switch (minVersion) {
+#ifdef WOLFSSL_DTLS13
             case 4:
                 minVersion = WOLFSSL_DTLSV1_3;
                 break;
+#endif /* WOLFSSL_DTLS13 */
             case 3:
                 minVersion = WOLFSSL_DTLSV1_2;
                 break;
@@ -2356,7 +2358,8 @@ THREAD_RETURN WOLFSSL_THREAD server_test(void* args)
             }
         }
 #endif /* WOLFSSL_DTLS13 */
-        wolfSSL_CTX_SetMinVersion(ctx, minVersion);
+        if (wolfSSL_CTX_SetMinVersion(ctx, minVersion) != WOLFSSL_SUCCESS)
+            err_sys_ex(catastrophic, "can't set minimum downgrade version");
     }
 
 #ifdef OPENSSL_COMPATIBLE_DEFAULTS