X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=src%2Fmain.cpp;h=5f98d49530ea5a45caee632d21698573b53ef745;hb=6a89317f621692e7d5c0c67b3a1440bf1b52b328;hp=d72a131a5f598d1cbfebad3bd95c36151226e92b;hpb=6789e99e4f70b9e779598f1a31552a87b5bd9360;p=novacoin.git

diff --git a/src/main.cpp b/src/main.cpp
index d72a131..5f98d49 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1492,6 +1492,16 @@ bool CBlock::CheckBlock() const
         if (!tx.CheckTransaction())
             return DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));
 
+    // Check for duplicate txids. This is caught by ConnectInputs(),
+    // but catching it earlier avoids a potential DoS attack:
+    set<uint256> uniqueTx;
+    BOOST_FOREACH(const CTransaction& tx, vtx)
+    {
+        uniqueTx.insert(tx.GetHash());
+    }
+    if (uniqueTx.size() != vtx.size())
+        return DoS(100, error("CheckBlock() : duplicate transaction"));
+
     // Check that it's not full of nonstandard transactions
     if (GetSigOpCount() > MAX_BLOCK_SIGOPS)
         return DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"));