secur32: Check for supported protocols when loading gnutls.

dlls/secur32/schannel_gnutls.c

@@ -23,6 +23,7 @@
 #include "wine/port.h"
 
 #include <stdarg.h>
+#include <stdio.h>
 #ifdef SONAME_LIBGNUTLS
 #include <gnutls/gnutls.h>
 #include <gnutls/crypto.h>
@@ -150,6 +151,7 @@ static const struct {
     DWORD enable_flag;
     const char *gnutls_flag;
 } protocol_priority_flags[] = {
+    {SP_PROT_TLS1_3_CLIENT, "VERS-TLS1.3"},
     {SP_PROT_TLS1_2_CLIENT, "VERS-TLS1.2"},
     {SP_PROT_TLS1_1_CLIENT, "VERS-TLS1.1"},
     {SP_PROT_TLS1_0_CLIENT, "VERS-TLS1.0"},
@@ -157,10 +159,41 @@ static const struct {
     /* {SP_PROT_SSL2_CLIENT} is not supported by GnuTLS */
 };
 
+static DWORD supported_protocols;
+
+static void check_supported_protocols(void)
+{
+    gnutls_session_t session;
+    char priority[64];
+    unsigned i;
+    int err;
+
+    err = pgnutls_init(&session, GNUTLS_CLIENT);
+    if (err != GNUTLS_E_SUCCESS)
+    {
+        pgnutls_perror(err);
+        return;
+    }
+
+    for(i = 0; i < ARRAY_SIZE(protocol_priority_flags); i++)
+    {
+        sprintf(priority, "NORMAL:-%s", protocol_priority_flags[i].gnutls_flag);
+        err = pgnutls_priority_set_direct(session, priority, NULL);
+        if (err == GNUTLS_E_SUCCESS)
+        {
+            TRACE("%s is supported\n", protocol_priority_flags[i].gnutls_flag);
+            supported_protocols |= protocol_priority_flags[i].enable_flag;
+        }
+        else
+            TRACE("%s is not supported\n", protocol_priority_flags[i].gnutls_flag);
+    }
+
+    pgnutls_deinit(session);
+}
+
 DWORD schan_imp_enabled_protocols(void)
 {
-    /* NOTE: No support for SSL 2.0 */
-    return SP_PROT_SSL3_CLIENT | SP_PROT_TLS1_0_CLIENT | SP_PROT_TLS1_1_CLIENT | SP_PROT_TLS1_2_CLIENT;
+    return supported_protocols;
 }
 
 BOOL schan_imp_create_session(schan_imp_session *session, schan_credentials *cred)
@@ -593,6 +626,7 @@ BOOL schan_imp_init(void)
         pgnutls_global_set_log_function(schan_gnutls_log);
     }
 
+    check_supported_protocols();
     return TRUE;
 
 fail: