From 7ac924cdb7bdad2601c46014e488e9190806b38c Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Fri, 21 Oct 2016 23:07:50 -0500
Subject: [PATCH 1/2] Disallow v0 transactions as a consensus rule

Closes #1557
---
 src/consensus/consensus.h           |  2 ++
 src/gtest/test_checktransaction.cpp | 10 ++++++++++
 src/main.cpp                        |  6 ++++++
 3 files changed, 18 insertions(+)

diff --git a/src/consensus/consensus.h b/src/consensus/consensus.h
index 0d1a3fdde..6472885a8 100644
--- a/src/consensus/consensus.h
+++ b/src/consensus/consensus.h
@@ -6,6 +6,8 @@
 #ifndef BITCOIN_CONSENSUS_CONSENSUS_H
 #define BITCOIN_CONSENSUS_CONSENSUS_H
 
+/** The minimum allowed transaction version (network rule) */
+static const int32_t MIN_TX_VERSION = 1;
 /** The maximum allowed size for a serialized block, in bytes (network rule) */
 static const unsigned int MAX_BLOCK_SIZE = 2000000;
 /** The maximum allowed number of signature check operations in a block (network rule) */
diff --git a/src/gtest/test_checktransaction.cpp b/src/gtest/test_checktransaction.cpp
index 7dd1b86d2..3849cf367 100644
--- a/src/gtest/test_checktransaction.cpp
+++ b/src/gtest/test_checktransaction.cpp
@@ -94,6 +94,16 @@ TEST(checktransaction_tests, valid_transaction) {
     EXPECT_TRUE(CheckTransactionWithoutProofVerification(tx, state));
 }
 
+TEST(checktransaction_tests, BadVersionTooLow) {
+    CMutableTransaction mtx = GetValidTransaction();
+    mtx.nVersion = 0;
+
+    CTransaction tx(mtx);
+    MockCValidationState state;
+    EXPECT_CALL(state, DoS(100, false, REJECT_INVALID, "bad-version-too-low", false)).Times(1);
+    CheckTransactionWithoutProofVerification(tx, state);
+}
+
 TEST(checktransaction_tests, bad_txns_vin_empty) {
     CMutableTransaction mtx = GetValidTransaction();
     mtx.vjoinsplit.resize(0);
diff --git a/src/main.cpp b/src/main.cpp
index 39bbf8ff7..3b089ede4 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -851,6 +851,12 @@ bool CheckTransactionWithoutProofVerification(const CTransaction& tx, CValidatio
 {
     // Basic checks that don't depend on any context
 
+    // Check transaction version
+    if (tx.nVersion < MIN_TX_VERSION) {
+        return state.DoS(100, error("CheckTransaction(): version too low"),
+                         REJECT_INVALID, "bad-version-too-low");
+    }
+
     // Transactions can contain empty `vin` and `vout` so long as
     // `vjoinsplit` is non-empty.
     if (tx.vin.empty() && tx.vjoinsplit.empty())

From f4f1b4b097f45de6bb6060a58752de5eb672dcd0 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Sat, 22 Oct 2016 11:09:07 -0500
Subject: [PATCH 2/2] Update sighash tests for new consensus rule

---
 src/test/sighash_tests.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/test/sighash_tests.cpp b/src/test/sighash_tests.cpp
index 164bba576..c825a8bad 100644
--- a/src/test/sighash_tests.cpp
+++ b/src/test/sighash_tests.cpp
@@ -237,8 +237,14 @@ BOOST_AUTO_TEST_CASE(sighash_from_data)
           stream >> tx;
 
           CValidationState state;
-          BOOST_CHECK_MESSAGE(CheckTransactionWithoutProofVerification(tx, state), strTest);
-          BOOST_CHECK(state.IsValid());
+          if (tx.nVersion < MIN_TX_VERSION) {
+              // Transaction must be invalid
+              BOOST_CHECK_MESSAGE(!CheckTransactionWithoutProofVerification(tx, state), strTest);
+              BOOST_CHECK(!state.IsValid());
+          } else {
+              BOOST_CHECK_MESSAGE(CheckTransactionWithoutProofVerification(tx, state), strTest);
+              BOOST_CHECK(state.IsValid());
+          }
 
           std::vector<unsigned char> raw = ParseHex(raw_script);
           scriptCode.insert(scriptCode.end(), raw.begin(), raw.end());