Move the ability to load the dasync engine into ssltestlib.c

The sslapitest has a helper function to load the dasync engine which is
useful for testing pipelining. We would like to have the same facility
from sslbuffertest, so we move the function to the common location
ssltestlib.c

Follow on from CVE-2024-4741

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24395)

3 files changed, 34 insertions, 21 deletions

diff --git a/test/helpers/ssltestlib.c b/test/helpers/ssltestlib.c
index f0dccfa54c..7277cdfe76 100644
--- a/test/helpers/ssltestlib.c
+++ b/test/helpers/ssltestlib.c
@@ -7,8 +7,17 @@
  * https://www.openssl.org/source/license.html
  */
 
+/*
+ * We need access to the deprecated low level ENGINE APIs for legacy purposes
+ * when the deprecated calls are not hidden
+ */
+#ifndef OPENSSL_NO_DEPRECATED_3_0
+# define OPENSSL_SUPPRESS_DEPRECATED
+#endif
+
 #include <string.h>
 
+#include <openssl/engine.h>
 #include "internal/nelem.h"
 #include "ssltestlib.h"
 #include "../testutil.h"
@@ -1182,3 +1191,27 @@ void shutdown_ssl_connection(SSL *serverssl, SSL *clientssl)
     SSL_free(serverssl);
     SSL_free(clientssl);
 }
+
+ENGINE *load_dasync(void)
+{
+#if !defined(OPENSSL_NO_TLS1_2) && !defined(OPENSSL_NO_DYNAMIC_ENGINE)
+    ENGINE *e;
+
+    if (!TEST_ptr(e = ENGINE_by_id("dasync")))
+        return NULL;
+
+    if (!TEST_true(ENGINE_init(e))) {
+        ENGINE_free(e);
+        return NULL;
+    }
+
+    if (!TEST_true(ENGINE_register_ciphers(e))) {
+        ENGINE_free(e);
+        return NULL;
+    }
+
+    return e;
+#else
+    return NULL;
+#endif
+}
diff --git a/test/helpers/ssltestlib.h b/test/helpers/ssltestlib.h
index 8e9daa5601..2777fb3047 100644
--- a/test/helpers/ssltestlib.h
+++ b/test/helpers/ssltestlib.h
@@ -59,4 +59,5 @@ typedef struct mempacket_st MEMPACKET;
 
 DEFINE_STACK_OF(MEMPACKET)
 
+ENGINE *load_dasync(void);
 #endif /* OSSL_TEST_SSLTESTLIB_H */
diff --git a/test/sslapitest.c b/test/sslapitest.c
index cbbe70cc9a..abb79804b0 100644
--- a/test/sslapitest.c
+++ b/test/sslapitest.c
@@ -10493,27 +10493,6 @@ end:
 #endif /* OSSL_NO_USABLE_TLS1_3 */
 
 #if !defined(OPENSSL_NO_TLS1_2) && !defined(OPENSSL_NO_DYNAMIC_ENGINE)
-
-static ENGINE *load_dasync(void)
-{
-    ENGINE *e;
-
-    if (!TEST_ptr(e = ENGINE_by_id("dasync")))
-        return NULL;
-
-    if (!TEST_true(ENGINE_init(e))) {
-        ENGINE_free(e);
-        return NULL;
-    }
-
-    if (!TEST_true(ENGINE_register_ciphers(e))) {
-        ENGINE_free(e);
-        return NULL;
-    }
-
-    return e;
-}
-
 /*
  * Test TLSv1.2 with a pipeline capable cipher. TLSv1.3 and DTLS do not
  * support this yet. The only pipeline capable cipher that we have is in the