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-rw-r--r--src/main.cpp22
1 files changed, 10 insertions, 12 deletions
diff --git a/src/main.cpp b/src/main.cpp
index 34b4c51d5f..b6a61f7da1 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3355,19 +3355,17 @@ void static ProcessGetData(CNode* pfrom)
BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
if (mi != mapBlockIndex.end())
{
- // If the requested block is at a height below our last
- // checkpoint, only serve it if it's in the checkpointed chain
- int nHeight = mi->second->nHeight;
- CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint();
- if (pcheckpoint && nHeight < pcheckpoint->nHeight) {
- if (!chainActive.Contains(mi->second))
- {
- LogPrintf("ProcessGetData(): ignoring request for old block that isn't in the main chain\n");
- } else {
- send = true;
- }
- } else {
+ if (chainActive.Contains(mi->second)) {
send = true;
+ } else {
+ // To prevent fingerprinting attacks, only send blocks outside of the active
+ // chain if they are valid, and no more than a month older than the best header
+ // chain we know about.
+ send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != NULL) &&
+ (mi->second->GetBlockTime() > pindexBestHeader->GetBlockTime() - 30 * 24 * 60 * 60);
+ if (!send) {
+ LogPrintf("ProcessGetData(): ignoring request from peer=%i for old block that isn't in the main chain\n", pfrom->GetId());
+ }
}
}
if (send)