config: Bridge line with a transport must have a ClientTransportPlugin

Fixes #25528

Signed-off-by: David Goulet <dgoulet@torproject.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/src/app/config/config.c b/src/app/config/config.c
index 04a82a5c43..79b67e7a90 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -2189,6 +2189,22 @@ options_act,(const or_options_t *old_options))
     }
   }
 
+  /* Validate that we actually have a configured transport for a Bridge line
+   * that has one.  This is done here because we require the bridge and
+   * transport to be added to the global list before doing the validation.
+   *
+   * In an ideal world, pt_parse_transport_line() would actually return a
+   * transport_t object so we could inspect it and thus do this step at
+   * validation time. */
+  SMARTLIST_FOREACH_BEGIN(bridge_list_get(), const bridge_info_t *, bi) {
+    const char *bi_transport_name = bridget_get_transport_name(bi);
+    if (bi_transport_name && !transport_get_by_name(bi_transport_name)) {
+      log_warn(LD_CONFIG, "Bridge line with transport %s is missing a "
+                          "ClientTransportPlugin line", bi_transport_name);
+      return -1;
+    }
+  } SMARTLIST_FOREACH_END(bi);
+
   if (options_act_server_transport(old_options) < 0)
     return -1;