proxy: bounds check data_len перед memcpy в handle_data — fix buffer overflow

src/proxy/tcp_proxy_server.c

@@ -326,6 +326,11 @@ int tcp_proxy_server_handle_data(struct UTUN_INSTANCE* inst, struct ETCP_CONN* c
     }
     size_t data_len = entry->len - TCP_PROXY_HDR_SIZE;
     if (data_len > 0) {
+        if (data_len > rc->tc->data_pool->object_size) {
+            DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "tcp_proxy_server: data_len=%zu > pool_sz=%zu, dropping sid=%08x",
+                        data_len, rc->tc->data_pool->object_size, stream_id);
+            queue_dgram_free(entry); queue_entry_free(entry); return -1;
+        }
         struct ll_entry* e = queue_entry_new_from_pool(rc->tc->entry_pool);
         uint8_t* buf = memory_pool_alloc(rc->tc->data_pool);
         if (e && buf) {