diff --git a/changes/ticket25528 b/changes/ticket25528
new file mode 100644
index 0000000000..cfc6c91fb7
--- /dev/null
+++ b/changes/ticket25528
@@ -0,0 +1,6 @@
+ o Minor bugfixes (client, bridge, configuration):
+ - Exit tor on a misconfiguration when the Bridge line has a transport but
+ no corresponding ClientTransportPlugin can be found. Prior to this fix,
+ tor would attempt to connect to the bridge directly without using the
+ transport leading to a possible leak on the wire. Fixes bug 25528;
+ bugfix on 0.2.6.1-alpha.
diff --git a/src/app/config/config.c b/src/app/config/config.c
index e6cc92e082..df89b6ede9 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;
diff --git a/src/feature/client/bridges.c b/src/feature/client/bridges.c
index 6e10defa13..8e2bb01661 100644
--- a/src/feature/client/bridges.c
+++ b/src/feature/client/bridges.c
@@ -164,6 +164,17 @@ bridge_get_addr_port(const bridge_info_t *bridge)
return &bridge->addrport_configured;
}
+/**
+ * Given a bridge, return the transport name. If none were configured,
+ * NULL is returned.
+ */
+const char *
+bridget_get_transport_name(const bridge_info_t *bridge)
+{
+ tor_assert(bridge);
+ return bridge->transport_name;
+}
+
/** If we have a bridge configured whose digest matches digest, or a
* bridge with no known digest whose address matches any of the
* tor_addr_port_t's in orports, return that bridge. Else return
diff --git a/src/feature/client/bridges.h b/src/feature/client/bridges.h
index 174149cf97..1b090e8649 100644
--- a/src/feature/client/bridges.h
+++ b/src/feature/client/bridges.h
@@ -23,6 +23,7 @@ void sweep_bridge_list(void);
const smartlist_t *bridge_list_get(void);
const uint8_t *bridge_get_rsa_id_digest(const bridge_info_t *bridge);
const tor_addr_port_t * bridge_get_addr_port(const bridge_info_t *bridge);
+const char *bridget_get_transport_name(const bridge_info_t *bridge);
bridge_info_t *get_configured_bridge_by_addr_port_digest(
const tor_addr_t *addr,
uint16_t port,