consensus: Utxoview based script validation

csn/client.go

@@ -126,6 +126,11 @@ func putBlockInPollard(
 	// thing first.  (Especially since that thing isn't committed to in the
 	// PoW, but the signatures are...
 
+	if !ub.CheckBlock(outskip) {
+		return fmt.Errorf("height %d hash %s block invalid",
+			ub.Height, ub.Block.BlockHash().String())
+	}
+
 	// sort before ingestion; verify up above unsorts...
 	ub.ExtraData.AccProof.SortTargets()
 	// Fills in the empty(nil) nieces for verification && deletion

util/udata.go

@@ -2,6 +2,12 @@ package util
 
 import (
 	"fmt"
+
+	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
 )
 
 // ProofsProveBlock checks the consistency of a UBlock.  Does the proof prove
@@ -72,3 +78,94 @@ func (ud *UData) Verify(nl uint64, h uint8) bool {
 	ud.AccProof.Targets = presort
 	return true
 }
+
+// ToUtxoView converts a UData into a btcd blockchain.UtxoViewpoint
+// all the data is there, just a bit different format.
+// Note that this needs blockchain.NewUtxoEntry() in btcd
+func (ud *UData) ToUtxoView() *blockchain.UtxoViewpoint {
+	v := blockchain.NewUtxoViewpoint()
+	m := v.Entries()
+	// loop through leafDatas and convert them into UtxoEntries (pretty much the
+	// same thing
+	for _, ld := range ud.UtxoData {
+		txo := wire.NewTxOut(ld.Amt, ld.PkScript)
+		utxo := blockchain.NewUtxoEntry(txo, ld.Height, ld.Coinbase)
+		m[ld.Outpoint] = utxo
+	}
+
+	return v
+}
+
+/*
+blockchain.NewUtxoEntry() looks like this:
+// NewUtxoEntry returns a new UtxoEntry built from the arguments.
+func NewUtxoEntry(
+	txOut *wire.TxOut, blockHeight int32, isCoinbase bool) *UtxoEntry {
+	var cbFlag txoFlags
+	if isCoinbase {
+		cbFlag |= tfCoinBase
+	}
+
+	return &UtxoEntry{
+		amount:      txOut.Value,
+		pkScript:    txOut.PkScript,
+		blockHeight: blockHeight,
+		packedFlags: cbFlag,
+	}
+}
+*/
+
+// CheckBlock does all internal block checks for a UBlock
+// right now checks the signatures
+func (ub *UBlock) CheckBlock(outskip []uint32) bool {
+
+	view := ub.ExtraData.ToUtxoView()
+	viewMap := view.Entries()
+	var txonum uint32
+
+	sigCache := txscript.NewSigCache(8192)
+	hashCache := txscript.NewHashCache(8192)
+
+	for txnum, tx := range ub.Block.Transactions {
+		outputsInTx := uint32(len(tx.TxOut))
+		if txnum == 0 {
+			txonum += outputsInTx
+			continue // skip checks for coinbase TX for now.  Or maybe it'll work?
+		}
+
+		utilTx := btcutil.NewTx(tx)
+		// hardcoded testnet3 for now
+		_, err := blockchain.CheckTransactionInputs(
+			utilTx, ub.Height, view, &chaincfg.TestNet3Params)
+		if err != nil {
+			fmt.Printf("Tx %s fails CheckTransactionInputs: %s\n",
+				utilTx.Hash().String(), err.Error())
+			return false
+		}
+
+		// no scriptflags for now
+		err = blockchain.ValidateTransactionScripts(
+			utilTx, view, 0, sigCache, hashCache)
+		if err != nil {
+			fmt.Printf("Tx %s fails ValidateTransactionScripts: %s\n",
+				utilTx.Hash().String(), err.Error())
+			return false
+		}
+
+		// add txos to the UtxoView if they're also consumed in this block
+		// (will be on the output skiplist from DedupeBlock)
+		// The order we do this in should ensure that a incorrectly ordered
+		// sequence (tx 5 spending tx 8) will fail here.
+		for len(outskip) > 0 && outskip[0] < txonum+outputsInTx {
+			idx := outskip[0] - txonum
+			skipTxo := wire.NewTxOut(tx.TxOut[idx].Value, tx.TxOut[idx].PkScript)
+			skippedEntry := blockchain.NewUtxoEntry(skipTxo, ub.Height, false)
+			skippedOutpoint := wire.OutPoint{Hash: tx.TxHash(), Index: idx}
+			viewMap[skippedOutpoint] = skippedEntry
+			outskip = outskip[1:] // pop off from output skiplist
+		}
+		txonum += outputsInTx
+	}
+
+	return true
+}

util/utils.go

@@ -161,7 +161,7 @@ func GetUDataFromFile(tipnum int32) (ud UData, err error) {
 
 // BlockToAdds turns all the new utxos in a msgblock into leafTxos
 // uses remember slice up to number of txos, but doesn't check that it's the
-// right lenght.  Similar with skiplist, doesn't check it.
+// right length.  Similar with skiplist, doesn't check it.
 func BlockToAddLeaves(blk wire.MsgBlock,
 	remember []bool, skiplist []uint32,
 	height int32) (leaves []accumulator.Leaf) {