[thrift][bugfix]try to fix thrift request overflow crash.

docs/root/version_history/current.rst

@@ -47,6 +47,7 @@ Bug Fixes
 * http: made the HeaderValues::prefix() method const.
 * jwt_authn: supports jwt payload without "iss" field.
 * rocketmq_proxy network-level filter: fixed an issue involving incorrect header lengths. In debug mode it causes crash and in release mode it causes underflow.
+* thrift_proxy: fixed crashing bug on request overflow.
 
 Removed Config or Runtime
 -------------------------

source/extensions/filters/network/thrift_proxy/router/router_impl.cc

@@ -410,6 +410,10 @@ FilterStatus Router::UpstreamRequest::start() {
     return FilterStatus::StopIteration;
   }
 
+  if (upstream_host_ == nullptr) {
+    return FilterStatus::StopIteration;
+  }
+
   return FilterStatus::Continue;
 }
 
@@ -502,9 +506,8 @@ void Router::UpstreamRequest::onResetStream(ConnectionPool::PoolFailureReason re
   switch (reason) {
   case ConnectionPool::PoolFailureReason::Overflow:
     parent_.callbacks_->sendLocalReply(
-        AppException(
-            AppExceptionType::InternalError,
-            fmt::format("too many connections to '{}'", upstream_host_->address()->asString())),
+        AppException(AppExceptionType::InternalError,
+                     "thrift upstream request: too many connections"),
         true);
     break;
   case ConnectionPool::PoolFailureReason::LocalConnectionFailure:
@@ -519,7 +522,9 @@ void Router::UpstreamRequest::onResetStream(ConnectionPool::PoolFailureReason re
       parent_.callbacks_->sendLocalReply(
           AppException(
               AppExceptionType::InternalError,
-              fmt::format("connection failure '{}'", upstream_host_->address()->asString())),
+              fmt::format("connection failure '{}'", (upstream_host_ != nullptr)
+                                                         ? upstream_host_->address()->asString()
+                                                         : "to upstream")),
           true);
       return;
     }

test/extensions/filters/network/thrift_proxy/router_test.cc

@@ -407,7 +407,8 @@ TEST_F(ThriftRouterTest, PoolOverflowFailure) {
         EXPECT_THAT(app_ex.what(), ContainsRegex(".*too many connections.*"));
         EXPECT_TRUE(end_stream);
       }));
-  context_.cluster_manager_.tcp_conn_pool_.poolFailure(ConnectionPool::PoolFailureReason::Overflow);
+  context_.cluster_manager_.tcp_conn_pool_.poolFailure(ConnectionPool::PoolFailureReason::Overflow,
+                                                       true);
 }
 
 TEST_F(ThriftRouterTest, PoolConnectionFailureWithOnewayMessage) {

test/mocks/tcp/mocks.cc

@@ -36,12 +36,15 @@ Envoy::ConnectionPool::MockCancellable* MockInstance::newConnectionImpl(Callback
   return &handles_.back();
 }
 
-void MockInstance::poolFailure(PoolFailureReason reason) {
+void MockInstance::poolFailure(PoolFailureReason reason, bool host_null) {
   Callbacks* cb = callbacks_.front();
   callbacks_.pop_front();
   handles_.pop_front();
-
-  cb->onPoolFailure(reason, host_);
+  if (host_null) {
+    cb->onPoolFailure(reason, nullptr);
+  } else {
+    cb->onPoolFailure(reason, host_);
+  }
 }
 
 void MockInstance::poolReady(Network::MockClientConnection& conn) {

test/mocks/tcp/mocks.h

@@ -58,7 +58,7 @@ class MockInstance : public Instance {
   MOCK_METHOD(Upstream::HostDescriptionConstSharedPtr, host, (), (const));
 
   Envoy::ConnectionPool::MockCancellable* newConnectionImpl(Callbacks& cb);
-  void poolFailure(PoolFailureReason reason);
+  void poolFailure(PoolFailureReason reason, bool host_null = false);
   void poolReady(Network::MockClientConnection& conn);
 
   // Invoked when connection_data_, having been assigned via poolReady is released.