From 4d3b091eb269a6cc275aba669b86079639dd9676 Mon Sep 17 00:00:00 2001
From: Jeremiah Buddenhagen <git@bitspill.net>
Date: Mon, 1 Oct 2018 12:12:15 -0700
Subject: [PATCH] CVE-2018-17144 fix
 https://bitcoincore.org/en/2018/09/20/notice/

---
 src/consensus/tx_verify.cpp | 16 +++++++---------
 src/consensus/tx_verify.h   |  2 +-
 src/validation.cpp          |  2 +-
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/consensus/tx_verify.cpp b/src/consensus/tx_verify.cpp
index 9878a29ab..1380f7ac8 100755
--- a/src/consensus/tx_verify.cpp
+++ b/src/consensus/tx_verify.cpp
@@ -157,7 +157,7 @@ int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& i
     return nSigOps;
 }
 
-bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fCheckDuplicateInputs)
+bool CheckTransaction(const CTransaction& tx, CValidationState &state)
 {
     // Basic checks that don't depend on any context
     if (tx.vin.empty())
@@ -181,14 +181,12 @@ bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fChe
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge");
     }
 
-    // Check for duplicate inputs - note that this check is slow so we skip it in CheckBlock
-    if (fCheckDuplicateInputs) {
-        std::set<COutPoint> vInOutPoints;
-        for (const auto& txin : tx.vin)
-        {
-            if (!vInOutPoints.insert(txin.prevout).second)
-                return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
-        }
+    // Check for duplicate inputs - note that this check is slow (no longer skipped due to CVE-2018-17144)
+    std::set<COutPoint> vInOutPoints;
+    for (const auto& txin : tx.vin)
+    {
+        if (!vInOutPoints.insert(txin.prevout).second)
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
     }
 
     if (tx.IsCoinBase())
diff --git a/src/consensus/tx_verify.h b/src/consensus/tx_verify.h
index d1f401a52..50122660b 100755
--- a/src/consensus/tx_verify.h
+++ b/src/consensus/tx_verify.h
@@ -17,7 +17,7 @@ class CValidationState;
 /** Transaction validation functions */
 
 /** Context-independent validity checks */
-bool CheckTransaction(const CTransaction& tx, CValidationState& state, bool fCheckDuplicateInputs=true);
+bool CheckTransaction(const CTransaction& tx, CValidationState& state);
 
 namespace Consensus {
 /**
diff --git a/src/validation.cpp b/src/validation.cpp
index 1c37b036b..521f55ce6 100755
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2824,7 +2824,7 @@ bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::P
 
     // Check transactions
     for (const auto& tx : block.vtx)
-        if (!CheckTransaction(*tx, state, false))
+        if (!CheckTransaction(*tx, state))
             return state.Invalid(false, state.GetRejectCode(), state.GetRejectReason(),
                                  strprintf("Transaction check failed (tx hash %s) %s", tx->GetHash().ToString(), state.GetDebugMessage()));