dnsdist: Check the responder's payload < the incoming buffer size

diff --git a/pdns/dnsdist-ecs.cc b/pdns/dnsdist-ecs.cc
index 02cd7bd14cb5b567139459caeafe1966319d6b05..6dfdbbc8f258c8d9985ee0b168dace964aa06205 100644 (file)
--- a/pdns/dnsdist-ecs.cc
+++ b/pdns/dnsdist-ecs.cc
@@ -30,7 +30,9 @@
 /* when we add EDNS to a query, we don't want to advertise
    a large buffer size */
 size_t g_EdnsUDPPayloadSize = 512;
-uint16_t g_PayloadSizeSelfGenAnswers{1232};
+static const uint16_t defaultPayloadSizeSelfGenAnswers = 1232;
+static_assert(defaultPayloadSizeSelfGenAnswers < s_udpIncomingBufferSize, "The UDP responder's payload size should be smaller or equal to our incoming buffer size");
+uint16_t g_PayloadSizeSelfGenAnswers{defaultPayloadSizeSelfGenAnswers};
 
 /* draft-ietf-dnsop-edns-client-subnet-04 "11.1.  Privacy" */
 uint16_t g_ECSSourcePrefixV4 = 24;