Merge pull request #288 from Castaglia/proxy-missing-default-reverse-servers

Address a possible null pointer dereference due to bad configurations…

Author: Castaglia

lib/proxy/reverse/db.c

@@ -1,6 +1,6 @@
 /*
  * ProFTPD - mod_proxy reverse datastore implementation
- * Copyright (c) 2012-2021 TJ Saunders
+ * Copyright (c) 2012-2025 TJ Saunders
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -1507,10 +1507,21 @@ static const struct proxy_conn *reverse_db_policy_next_backend(pool *p,
 
  if (proxy_reverse_policy_is_sticky(policy_id) != TRUE) {
  if (conns == NULL &&
- default_backends != NULL &&
  db_backends == NULL) {
- conns = default_backends->elts;
- nelts = default_backends->nelts;
+
+ if (default_backends != NULL) {
+ conns = default_backends->elts;
+ nelts = default_backends->nelts;
+
+ } else {
+ /* Prevent possible null pointer dereferences later due to missing
+ * default URIs for non-sticky ConnectPolicy configurations.
+ */
+ pr_log_writefile(proxy_logfd, MOD_PROXY_VERSION,
+ "missing required default/global ProxyReverseServers");
+ errno = EPERM;
+ return NULL;
+ }
  }
  }