1 files changed, 12 insertions, 0 deletions
diff --git a/src/main.cpp b/src/main.cpp
index 5e17ec6251..55e3d934ea 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -5450,7 +5450,19 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
 
         if (it->second->nHeight < chainActive.Height() - MAX_BLOCKTXN_DEPTH) {
+            // If an older block is requested (should never happen in practice,
+            // but can happen in tests) send a block response instead of a
+            // blocktxn response. Sending a full block response instead of a
+            // small blocktxn response is preferable in the case where a peer
+            // might maliciously send lots of getblocktxn requests to trigger
+            // expensive disk reads, because it will require the peer to
+            // actually receive all the data read from disk over the network.
             LogPrint("net", "Peer %d sent us a getblocktxn for a block > %i deep", pfrom->id, MAX_BLOCKTXN_DEPTH);
+            CInv vInv;
+            vInv.type = State(pfrom->GetId())->fWantsCmpctWitness ? MSG_WITNESS_BLOCK : MSG_BLOCK;
+            vInv.hash = req.blockhash;
+            pfrom->vRecvGetData.push_back(vInv);
+            ProcessGetData(pfrom, chainparams.GetConsensus(), connman);
             return true;
         }