core_dns Drop incoming packets containing a different question from what we asked

1 files changed, 7 insertions, 0 deletions

diff --git a/src/coremods/core_dns.cpp b/src/coremods/core_dns.cpp
index f4f85e253..d4214b9a5 100644
--- a/src/coremods/core_dns.cpp
+++ b/src/coremods/core_dns.cpp
@@ -527,6 +527,13 @@ class MyManager : public Manager, public Timer, public EventHandler
 			return;
 		}
 
+		if (static_cast<Question&>(*request) != recv_packet.question)
+		{
+			// This can happen under high latency, drop it silently, do not fail the request
+			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Received an answer that isn't for a question we asked");
+			return;
+		}
+
 		if (recv_packet.flags & QUERYFLAGS_OPCODE)
 		{
 			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Received a nonstandard query");