Don't store empty string before macro and empty macro result

Author: Marc Stern

apache2/re_actions.c

@@ -228,18 +228,20 @@ int expand_macros(modsec_rec *msr, msc_string *var, msre_rule *rule, apr_pool_t
                 msre_var *var_resolved = NULL;
 
                 /* Add the text part before the macro to the array. */
+                if (p != text_start) {
                 part = (msc_string *)apr_pcalloc(mptmp, sizeof(msc_string));
                 if (part == NULL) return -1;
                 part->value_len = p - text_start;
                 part->value = apr_pstrmemdup(mptmp, text_start, part->value_len);
                 *(msc_string **)apr_array_push(arr) = part;
+                }
 
                 /* Resolve the macro and add that to the array. */
                 var_resolved = msre_create_var_ex(mptmp, msr->modsecurity->msre, var_name, var_value,
                     msr, &my_error_msg);
                 if (var_resolved != NULL) {
                     var_generated = generate_single_var(msr, var_resolved, NULL, rule, mptmp);
-                    if (var_generated != NULL) {
+                    if (var_generated != NULL && var_generated->value_len) {
                         part = (msc_string *)apr_pcalloc(mptmp, sizeof(msc_string));
                         if (part == NULL) return -1;
                         part->value_len = var_generated->value_len;