From fa2b52af32f6a4b9c22c270f36e92960c29ef364 Mon Sep 17 00:00:00 2001
From: MarcoFalke <falke.marco@gmail.com>
Date: Mon, 13 May 2019 15:38:10 -0400
Subject: [PATCH] Disallow extended encoding for non-witness transactions (take
 3)

---
 src/net_processing.cpp        | 21 ++++++++++-----------
 test/functional/p2p_segwit.py | 26 +++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index b3facdcd3..3254c6a19 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -3288,23 +3288,22 @@ bool PeerLogicValidation::ProcessMessages(CNode* pfrom, std::atomic<bool>& inter
         if (m_enable_bip61) {
             connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_MALFORMED, std::string("error parsing message")));
         }
-        if (strstr(e.what(), "end of data"))
-        {
+        if (strstr(e.what(), "end of data")) {
             // Allow exceptions from under-length message on vRecv
             LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught, normally caused by a message being shorter than its stated length\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
-        }
-        else if (strstr(e.what(), "size too large"))
-        {
+        } else if (strstr(e.what(), "size too large")) {
             // Allow exceptions from over-long size
             LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
-        }
-        else if (strstr(e.what(), "non-canonical ReadCompactSize()"))
-        {
+        } else if (strstr(e.what(), "non-canonical ReadCompactSize()")) {
             // Allow exceptions from non-canonical encoding
             LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
-        }
-        else
-        {
+        } else if (strstr(e.what(), "Superfluous witness record")) {
+            // Allow exceptions from illegal witness encoding
+            LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
+        } else if (strstr(e.what(), "Unknown transaction optional data")) {
+            // Allow exceptions from unknown witness encoding
+            LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what());
+        } else {
             PrintExceptionContinue(&e, "ProcessMessages()");
         }
     }
diff --git a/test/functional/p2p_segwit.py b/test/functional/p2p_segwit.py
index 000c30646..df0f9fa36 100755
--- a/test/functional/p2p_segwit.py
+++ b/test/functional/p2p_segwit.py
@@ -2038,9 +2038,9 @@ class SegWitTest(BitcoinTestFramework):
         # TODO: test p2sh sigop counting
 
     def test_superfluous_witness(self):
-        # Serialization of tx that puts witness flag to 1 always
+        # Serialization of tx that puts witness flag to 3 always
         def serialize_with_bogus_witness(tx):
-            flags = 1
+            flags = 3
             r = b""
             r += struct.pack("<i", tx.nVersion)
             if flags:
@@ -2059,9 +2059,29 @@ class SegWitTest(BitcoinTestFramework):
             r += struct.pack("<I", tx.nLockTime)
             return r
 
-        raw = self.nodes[0].createrawtransaction([{"txid":"00"*32, "vout":0}], {self.nodes[0].getnewaddress():1})
+        class msg_bogus_tx(msg_tx):
+            def serialize(self):
+                return serialize_with_bogus_witness(self.tx)
+
+        self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(address_type='bech32'), 5)
+        self.nodes[0].generate(1)
+        unspent = next(u for u in self.nodes[0].listunspent() if u['spendable'] and u['address'].startswith('bcrt'))
+
+        raw = self.nodes[0].createrawtransaction([{"txid": unspent['txid'], "vout": unspent['vout']}], {self.nodes[0].getnewaddress(): 1})
         tx = FromHex(CTransaction(), raw)
         assert_raises_rpc_error(-22, "TX decode failed", self.nodes[0].decoderawtransaction, serialize_with_bogus_witness(tx).hex())
+        with self.nodes[0].assert_debug_log(['Superfluous witness record']):
+            self.nodes[0].p2p.send_message(msg_bogus_tx(tx))
+            self.nodes[0].p2p.sync_with_ping()
+        raw = self.nodes[0].signrawtransactionwithwallet(raw)
+        assert raw['complete']
+        raw = raw['hex']
+        tx = FromHex(CTransaction(), raw)
+        assert_raises_rpc_error(-22, "TX decode failed", self.nodes[0].decoderawtransaction, serialize_with_bogus_witness(tx).hex())
+        with self.nodes[0].assert_debug_log(['Unknown transaction optional data']):
+            self.nodes[0].p2p.send_message(msg_bogus_tx(tx))
+            self.nodes[0].p2p.sync_with_ping()
+
 
 if __name__ == '__main__':
     SegWitTest().main()