txscript: Separate signing code.
This commit separate the transaction signing code into sign.go and the related tests into sign_test.go.
This commit is contained in:
Dave Collins
parent
8dd7412a84
commit
3fc2444309
4 changed files with 2125 additions and 2097 deletions
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@ -13,7 +13,6 @@ import (
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"time"
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"time"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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"github.com/btcsuite/btcutil"
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)
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)
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@ -770,402 +769,6 @@ func MultiSigScript(pubkeys []*btcutil.AddressPubKey, nrequired int) ([]byte, er
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return builder.Script()
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return builder.Script()
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}
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}
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// SignatureScript creates an input signature script for tx to spend
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// BTC sent from a previous output to the owner of privKey. tx must
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// include all transaction inputs and outputs, however txin scripts are
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// allowed to be filled or empty. The returned script is calculated to
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// be used as the idx'th txin sigscript for tx. subscript is the PkScript
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// of the previous output being used as the idx'th input. privKey is
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// serialized in either a compressed or uncompressed format based on
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// compress. This format must match the same format used to generate
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// the payment address, or the script validation will fail.
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func SignatureScript(tx *wire.MsgTx, idx int, subscript []byte, hashType SigHashType, privKey *btcec.PrivateKey, compress bool) ([]byte, error) {
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sig, err := RawTxInSignature(tx, idx, subscript, hashType, privKey)
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if err != nil {
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return nil, err
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}
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pk := (*btcec.PublicKey)(&privKey.PublicKey)
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var pkData []byte
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if compress {
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pkData = pk.SerializeCompressed()
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} else {
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pkData = pk.SerializeUncompressed()
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}
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return NewScriptBuilder().AddData(sig).AddData(pkData).Script()
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}
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// RawTxInSignature returns the serialized ECDSA signature for the input
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// idx of the given transaction, with hashType appended to it.
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func RawTxInSignature(tx *wire.MsgTx, idx int, subScript []byte,
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hashType SigHashType, key *btcec.PrivateKey) ([]byte, error) {
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parsedScript, err := parseScript(subScript)
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if err != nil {
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return nil, fmt.Errorf("cannot parse output script: %v", err)
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}
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hash := calcScriptHash(parsedScript, hashType, tx, idx)
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signature, err := key.Sign(hash)
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if err != nil {
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return nil, fmt.Errorf("cannot sign tx input: %s", err)
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}
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return append(signature.Serialize(), byte(hashType)), nil
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}
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func p2pkSignatureScript(tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType, privKey *btcec.PrivateKey) ([]byte, error) {
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sig, err := RawTxInSignature(tx, idx, subScript, hashType, privKey)
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if err != nil {
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return nil, err
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}
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return NewScriptBuilder().AddData(sig).Script()
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}
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// signMultiSig signs as many of the outputs in the provided multisig script as
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// possible. It returns the generated script and a boolean if the script fulfils
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// the contract (i.e. nrequired signatures are provided). Since it is arguably
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// legal to not be able to sign any of the outputs, no error is returned.
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func signMultiSig(tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType,
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addresses []btcutil.Address, nRequired int, kdb KeyDB) ([]byte, bool) {
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// We start with a single OP_FALSE to work around the (now standard)
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// but in the reference implementation that causes a spurious pop at
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// the end of OP_CHECKMULTISIG.
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builder := NewScriptBuilder().AddOp(OP_FALSE)
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signed := 0
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for _, addr := range addresses {
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key, _, err := kdb.GetKey(addr)
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if err != nil {
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continue
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}
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sig, err := RawTxInSignature(tx, idx, subScript, hashType, key)
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if err != nil {
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continue
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}
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builder.AddData(sig)
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signed++
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if signed == nRequired {
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break
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}
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}
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script, _ := builder.Script()
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return script, signed == nRequired
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}
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func sign(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
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subScript []byte, hashType SigHashType, kdb KeyDB, sdb ScriptDB) ([]byte,
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ScriptClass, []btcutil.Address, int, error) {
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class, addresses, nrequired, err := ExtractPkScriptAddrs(subScript,
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chainParams)
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if err != nil {
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return nil, NonStandardTy, nil, 0, err
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}
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switch class {
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case PubKeyTy:
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// look up key for address
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key, _, err := kdb.GetKey(addresses[0])
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if err != nil {
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return nil, class, nil, 0, err
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}
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script, err := p2pkSignatureScript(tx, idx, subScript, hashType,
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key)
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if err != nil {
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return nil, class, nil, 0, err
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}
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return script, class, addresses, nrequired, nil
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case PubKeyHashTy:
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// look up key for address
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key, compressed, err := kdb.GetKey(addresses[0])
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if err != nil {
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return nil, class, nil, 0, err
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}
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script, err := SignatureScript(tx, idx, subScript, hashType,
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key, compressed)
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if err != nil {
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return nil, class, nil, 0, err
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}
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return script, class, addresses, nrequired, nil
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case ScriptHashTy:
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script, err := sdb.GetScript(addresses[0])
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if err != nil {
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return nil, class, nil, 0, err
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}
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return script, class, addresses, nrequired, nil
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case MultiSigTy:
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script, _ := signMultiSig(tx, idx, subScript, hashType,
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addresses, nrequired, kdb)
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return script, class, addresses, nrequired, nil
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case NullDataTy:
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return nil, class, nil, 0,
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errors.New("can't sign NULLDATA transactions")
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default:
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return nil, class, nil, 0,
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errors.New("can't sign unknown transactions")
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}
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}
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// mergeScripts merges sigScript and prevScript assuming they are both
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// partial solutions for pkScript spending output idx of tx. class, addresses
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// and nrequired are the result of extracting the addresses from pkscript.
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// The return value is the best effort merging of the two scripts. Calling this
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// function with addresses, class and nrequired that do not match pkScript is
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// an error and results in undefined behaviour.
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func mergeScripts(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
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pkScript []byte, class ScriptClass, addresses []btcutil.Address,
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nRequired int, sigScript, prevScript []byte) []byte {
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// TODO(oga) the scripthash and multisig paths here are overly
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// inefficient in that they will recompute already known data.
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// some internal refactoring could probably make this avoid needless
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// extra calculations.
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switch class {
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case ScriptHashTy:
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// Remove the last push in the script and then recurse.
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// this could be a lot less inefficient.
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sigPops, err := parseScript(sigScript)
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if err != nil || len(sigPops) == 0 {
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return prevScript
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}
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prevPops, err := parseScript(prevScript)
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if err != nil || len(prevPops) == 0 {
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return sigScript
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}
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// assume that script in sigPops is the correct one, we just
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// made it.
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script := sigPops[len(sigPops)-1].data
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// We already know this information somewhere up the stack.
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class, addresses, nrequired, err :=
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ExtractPkScriptAddrs(script, chainParams)
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// regenerate scripts.
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sigScript, _ := unparseScript(sigPops)
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prevScript, _ := unparseScript(prevPops)
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// Merge
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mergedScript := mergeScripts(chainParams, tx, idx, script,
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class, addresses, nrequired, sigScript, prevScript)
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// Reappend the script and return the result.
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builder := NewScriptBuilder()
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builder.script = mergedScript
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builder.AddData(script)
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finalScript, _ := builder.Script()
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return finalScript
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case MultiSigTy:
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return mergeMultiSig(tx, idx, addresses, nRequired, pkScript,
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sigScript, prevScript)
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// It doesn't actualy make sense to merge anything other than multiig
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// and scripthash (because it could contain multisig). Everything else
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// has either zero signature, can't be spent, or has a single signature
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// which is either present or not. The other two cases are handled
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// above. In the conflict case here we just assume the longest is
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// correct (this matches behaviour of the reference implementation).
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default:
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if len(sigScript) > len(prevScript) {
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return sigScript
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}
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return prevScript
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}
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}
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// mergeMultiSig combines the two signature scripts sigScript and prevScript
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// that both provide signatures for pkScript in output idx of tx. addresses
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// and nRequired should be the results from extracting the addresses from
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// pkScript. Since this function is internal only we assume that the arguments
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// have come from other functions internally and thus are all consistent with
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// each other, behaviour is undefined if this contract is broken.
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func mergeMultiSig(tx *wire.MsgTx, idx int, addresses []btcutil.Address,
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nRequired int, pkScript, sigScript, prevScript []byte) []byte {
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// This is an internal only function and we already parsed this script
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// as ok for multisig (this is how we got here), so if this fails then
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// all assumptions are broken and who knows which way is up?
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pkPops, _ := parseScript(pkScript)
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sigPops, err := parseScript(sigScript)
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if err != nil || len(sigPops) == 0 {
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return prevScript
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}
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prevPops, err := parseScript(prevScript)
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if err != nil || len(prevPops) == 0 {
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return sigScript
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}
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// Convenience function to avoid duplication.
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extractSigs := func(pops []parsedOpcode, sigs [][]byte) [][]byte {
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for _, pop := range pops {
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if len(pop.data) != 0 {
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sigs = append(sigs, pop.data)
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}
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}
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return sigs
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}
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possibleSigs := make([][]byte, 0, len(sigPops)+len(prevPops))
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possibleSigs = extractSigs(sigPops, possibleSigs)
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possibleSigs = extractSigs(prevPops, possibleSigs)
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// Now we need to match the signatures to pubkeys, the only real way to
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// do that is to try to verify them all and match it to the pubkey
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// that verifies it. we then can go through the addresses in order
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// to build our script. Anything that doesn't parse or doesn't verify we
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// throw away.
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addrToSig := make(map[string][]byte)
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sigLoop:
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for _, sig := range possibleSigs {
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// can't have a valid signature that doesn't at least have a
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// hashtype, in practise it is even longer than this. but
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// that'll be checked next.
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if len(sig) < 1 {
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continue
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}
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tSig := sig[:len(sig)-1]
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hashType := SigHashType(sig[len(sig)-1])
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pSig, err := btcec.ParseDERSignature(tSig, btcec.S256())
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if err != nil {
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continue
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}
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// We have to do this each round since hash types may vary
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// between signatures and so the hash will vary. We can,
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// however, assume no sigs etc are in the script since that
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// would make the transaction nonstandard and thus not
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// MultiSigTy, so we just need to hash the full thing.
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hash := calcScriptHash(pkPops, hashType, tx, idx)
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for _, addr := range addresses {
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// All multisig addresses should be pubkey addreses
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// it is an error to call this internal function with
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// bad input.
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pkaddr := addr.(*btcutil.AddressPubKey)
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pubKey := pkaddr.PubKey()
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// If it matches we put it in the map. We only
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// can take one signature per public key so if we
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// already have one, we can throw this away.
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if pSig.Verify(hash, pubKey) {
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aStr := addr.EncodeAddress()
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if _, ok := addrToSig[aStr]; !ok {
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addrToSig[aStr] = sig
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}
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continue sigLoop
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}
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}
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}
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// Extra opcode to handle the extra arg consumed (due to previous bugs
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// in the reference implementation).
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builder := NewScriptBuilder().AddOp(OP_FALSE)
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doneSigs := 0
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// This assumes that addresses are in the same order as in the script.
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for _, addr := range addresses {
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sig, ok := addrToSig[addr.EncodeAddress()]
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if !ok {
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continue
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}
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builder.AddData(sig)
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doneSigs++
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if doneSigs == nRequired {
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break
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}
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}
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// padding for missing ones.
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for i := doneSigs; i < nRequired; i++ {
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builder.AddOp(OP_0)
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}
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script, _ := builder.Script()
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return script
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}
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// KeyDB is an interface type provided to SignTxOutput, it encapsulates
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// any user state required to get the private keys for an address.
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type KeyDB interface {
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GetKey(btcutil.Address) (*btcec.PrivateKey, bool, error)
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}
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// KeyClosure implements ScriptDB with a closure
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type KeyClosure func(btcutil.Address) (*btcec.PrivateKey, bool, error)
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// GetKey implements KeyDB by returning the result of calling the closure
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func (kc KeyClosure) GetKey(address btcutil.Address) (*btcec.PrivateKey,
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bool, error) {
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return kc(address)
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}
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// ScriptDB is an interface type provided to SignTxOutput, it encapsulates
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// any user state required to get the scripts for an pay-to-script-hash address.
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type ScriptDB interface {
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GetScript(btcutil.Address) ([]byte, error)
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}
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// ScriptClosure implements ScriptDB with a closure
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type ScriptClosure func(btcutil.Address) ([]byte, error)
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// GetScript implements ScriptDB by returning the result of calling the closure
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func (sc ScriptClosure) GetScript(address btcutil.Address) ([]byte, error) {
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return sc(address)
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}
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// SignTxOutput signs output idx of the given tx to resolve the script given in
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// pkScript with a signature type of hashType. Any keys required will be
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// looked up by calling getKey() with the string of the given address.
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// Any pay-to-script-hash signatures will be similarly looked up by calling
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// getScript. If previousScript is provided then the results in previousScript
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// will be merged in a type-dependant manner with the newly generated.
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// signature script.
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|
||||||
func SignTxOutput(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
|
|
||||||
pkScript []byte, hashType SigHashType, kdb KeyDB, sdb ScriptDB,
|
|
||||||
previousScript []byte) ([]byte, error) {
|
|
||||||
|
|
||||||
sigScript, class, addresses, nrequired, err := sign(chainParams, tx,
|
|
||||||
idx, pkScript, hashType, kdb, sdb)
|
|
||||||
if err != nil {
|
|
||||||
return nil, err
|
|
||||||
}
|
|
||||||
|
|
||||||
if class == ScriptHashTy {
|
|
||||||
// TODO keep the sub addressed and pass down to merge.
|
|
||||||
realSigScript, _, _, _, err := sign(chainParams, tx, idx,
|
|
||||||
sigScript, hashType, kdb, sdb)
|
|
||||||
if err != nil {
|
|
||||||
return nil, err
|
|
||||||
}
|
|
||||||
|
|
||||||
// This is a bad thing. Append the p2sh script as the last
|
|
||||||
// push in the script.
|
|
||||||
builder := NewScriptBuilder()
|
|
||||||
builder.script = realSigScript
|
|
||||||
builder.AddData(sigScript)
|
|
||||||
|
|
||||||
sigScript, _ = builder.Script()
|
|
||||||
// TODO keep a copy of the script for merging.
|
|
||||||
}
|
|
||||||
|
|
||||||
// Merge scripts. with any previous data, if any.
|
|
||||||
mergedScript := mergeScripts(chainParams, tx, idx, pkScript, class,
|
|
||||||
addresses, nrequired, sigScript, previousScript)
|
|
||||||
return mergedScript, nil
|
|
||||||
}
|
|
||||||
|
|
||||||
// expectedInputs returns the number of arguments required by a script.
|
// expectedInputs returns the number of arguments required by a script.
|
||||||
// If the script is of unnown type such that the number can not be determined
|
// If the script is of unnown type such that the number can not be determined
|
||||||
// then -1 is returned. We are an internal function and thus assume that class
|
// then -1 is returned. We are an internal function and thus assume that class
|
||||||
|
|
|
||||||
File diff suppressed because it is too large
Load diff
411
txscript/sign.go
Normal file
411
txscript/sign.go
Normal file
|
|
@ -0,0 +1,411 @@
|
||||||
|
// Copyright (c) 2013-2015 Conformal Systems LLC.
|
||||||
|
// Use of this source code is governed by an ISC
|
||||||
|
// license that can be found in the LICENSE file.
|
||||||
|
|
||||||
|
package txscript
|
||||||
|
|
||||||
|
import (
|
||||||
|
"errors"
|
||||||
|
"fmt"
|
||||||
|
|
||||||
|
"github.com/btcsuite/btcd/btcec"
|
||||||
|
"github.com/btcsuite/btcd/chaincfg"
|
||||||
|
"github.com/btcsuite/btcd/wire"
|
||||||
|
"github.com/btcsuite/btcutil"
|
||||||
|
)
|
||||||
|
|
||||||
|
// RawTxInSignature returns the serialized ECDSA signature for the input idx of
|
||||||
|
// the given transaction, with hashType appended to it.
|
||||||
|
func RawTxInSignature(tx *wire.MsgTx, idx int, subScript []byte,
|
||||||
|
hashType SigHashType, key *btcec.PrivateKey) ([]byte, error) {
|
||||||
|
|
||||||
|
parsedScript, err := parseScript(subScript)
|
||||||
|
if err != nil {
|
||||||
|
return nil, fmt.Errorf("cannot parse output script: %v", err)
|
||||||
|
}
|
||||||
|
hash := calcScriptHash(parsedScript, hashType, tx, idx)
|
||||||
|
signature, err := key.Sign(hash)
|
||||||
|
if err != nil {
|
||||||
|
return nil, fmt.Errorf("cannot sign tx input: %s", err)
|
||||||
|
}
|
||||||
|
|
||||||
|
return append(signature.Serialize(), byte(hashType)), nil
|
||||||
|
}
|
||||||
|
|
||||||
|
// SignatureScript creates an input signature script for tx to spend BTC sent
|
||||||
|
// from a previous output to the owner of privKey. tx must include all
|
||||||
|
// transaction inputs and outputs, however txin scripts are allowed to be filled
|
||||||
|
// or empty. The returned script is calculated to be used as the idx'th txin
|
||||||
|
// sigscript for tx. subscript is the PkScript of the previous output being used
|
||||||
|
// as the idx'th input. privKey is serialized in either a compressed or
|
||||||
|
// uncompressed format based on compress. This format must match the same format
|
||||||
|
// used to generate the payment address, or the script validation will fail.
|
||||||
|
func SignatureScript(tx *wire.MsgTx, idx int, subscript []byte, hashType SigHashType, privKey *btcec.PrivateKey, compress bool) ([]byte, error) {
|
||||||
|
sig, err := RawTxInSignature(tx, idx, subscript, hashType, privKey)
|
||||||
|
if err != nil {
|
||||||
|
return nil, err
|
||||||
|
}
|
||||||
|
|
||||||
|
pk := (*btcec.PublicKey)(&privKey.PublicKey)
|
||||||
|
var pkData []byte
|
||||||
|
if compress {
|
||||||
|
pkData = pk.SerializeCompressed()
|
||||||
|
} else {
|
||||||
|
pkData = pk.SerializeUncompressed()
|
||||||
|
}
|
||||||
|
|
||||||
|
return NewScriptBuilder().AddData(sig).AddData(pkData).Script()
|
||||||
|
}
|
||||||
|
|
||||||
|
func p2pkSignatureScript(tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType, privKey *btcec.PrivateKey) ([]byte, error) {
|
||||||
|
sig, err := RawTxInSignature(tx, idx, subScript, hashType, privKey)
|
||||||
|
if err != nil {
|
||||||
|
return nil, err
|
||||||
|
}
|
||||||
|
|
||||||
|
return NewScriptBuilder().AddData(sig).Script()
|
||||||
|
}
|
||||||
|
|
||||||
|
// signMultiSig signs as many of the outputs in the provided multisig script as
|
||||||
|
// possible. It returns the generated script and a boolean if the script fulfils
|
||||||
|
// the contract (i.e. nrequired signatures are provided). Since it is arguably
|
||||||
|
// legal to not be able to sign any of the outputs, no error is returned.
|
||||||
|
func signMultiSig(tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType,
|
||||||
|
addresses []btcutil.Address, nRequired int, kdb KeyDB) ([]byte, bool) {
|
||||||
|
// We start with a single OP_FALSE to work around the (now standard)
|
||||||
|
// but in the reference implementation that causes a spurious pop at
|
||||||
|
// the end of OP_CHECKMULTISIG.
|
||||||
|
builder := NewScriptBuilder().AddOp(OP_FALSE)
|
||||||
|
signed := 0
|
||||||
|
for _, addr := range addresses {
|
||||||
|
key, _, err := kdb.GetKey(addr)
|
||||||
|
if err != nil {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
sig, err := RawTxInSignature(tx, idx, subScript, hashType, key)
|
||||||
|
if err != nil {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
|
||||||
|
builder.AddData(sig)
|
||||||
|
signed++
|
||||||
|
if signed == nRequired {
|
||||||
|
break
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
script, _ := builder.Script()
|
||||||
|
return script, signed == nRequired
|
||||||
|
}
|
||||||
|
|
||||||
|
func sign(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
|
||||||
|
subScript []byte, hashType SigHashType, kdb KeyDB, sdb ScriptDB) ([]byte,
|
||||||
|
ScriptClass, []btcutil.Address, int, error) {
|
||||||
|
|
||||||
|
class, addresses, nrequired, err := ExtractPkScriptAddrs(subScript,
|
||||||
|
chainParams)
|
||||||
|
if err != nil {
|
||||||
|
return nil, NonStandardTy, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
switch class {
|
||||||
|
case PubKeyTy:
|
||||||
|
// look up key for address
|
||||||
|
key, _, err := kdb.GetKey(addresses[0])
|
||||||
|
if err != nil {
|
||||||
|
return nil, class, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
script, err := p2pkSignatureScript(tx, idx, subScript, hashType,
|
||||||
|
key)
|
||||||
|
if err != nil {
|
||||||
|
return nil, class, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
return script, class, addresses, nrequired, nil
|
||||||
|
case PubKeyHashTy:
|
||||||
|
// look up key for address
|
||||||
|
key, compressed, err := kdb.GetKey(addresses[0])
|
||||||
|
if err != nil {
|
||||||
|
return nil, class, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
script, err := SignatureScript(tx, idx, subScript, hashType,
|
||||||
|
key, compressed)
|
||||||
|
if err != nil {
|
||||||
|
return nil, class, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
return script, class, addresses, nrequired, nil
|
||||||
|
case ScriptHashTy:
|
||||||
|
script, err := sdb.GetScript(addresses[0])
|
||||||
|
if err != nil {
|
||||||
|
return nil, class, nil, 0, err
|
||||||
|
}
|
||||||
|
|
||||||
|
return script, class, addresses, nrequired, nil
|
||||||
|
case MultiSigTy:
|
||||||
|
script, _ := signMultiSig(tx, idx, subScript, hashType,
|
||||||
|
addresses, nrequired, kdb)
|
||||||
|
return script, class, addresses, nrequired, nil
|
||||||
|
case NullDataTy:
|
||||||
|
return nil, class, nil, 0,
|
||||||
|
errors.New("can't sign NULLDATA transactions")
|
||||||
|
default:
|
||||||
|
return nil, class, nil, 0,
|
||||||
|
errors.New("can't sign unknown transactions")
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// mergeScripts merges sigScript and prevScript assuming they are both
|
||||||
|
// partial solutions for pkScript spending output idx of tx. class, addresses
|
||||||
|
// and nrequired are the result of extracting the addresses from pkscript.
|
||||||
|
// The return value is the best effort merging of the two scripts. Calling this
|
||||||
|
// function with addresses, class and nrequired that do not match pkScript is
|
||||||
|
// an error and results in undefined behaviour.
|
||||||
|
func mergeScripts(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
|
||||||
|
pkScript []byte, class ScriptClass, addresses []btcutil.Address,
|
||||||
|
nRequired int, sigScript, prevScript []byte) []byte {
|
||||||
|
|
||||||
|
// TODO(oga) the scripthash and multisig paths here are overly
|
||||||
|
// inefficient in that they will recompute already known data.
|
||||||
|
// some internal refactoring could probably make this avoid needless
|
||||||
|
// extra calculations.
|
||||||
|
switch class {
|
||||||
|
case ScriptHashTy:
|
||||||
|
// Remove the last push in the script and then recurse.
|
||||||
|
// this could be a lot less inefficient.
|
||||||
|
sigPops, err := parseScript(sigScript)
|
||||||
|
if err != nil || len(sigPops) == 0 {
|
||||||
|
return prevScript
|
||||||
|
}
|
||||||
|
prevPops, err := parseScript(prevScript)
|
||||||
|
if err != nil || len(prevPops) == 0 {
|
||||||
|
return sigScript
|
||||||
|
}
|
||||||
|
|
||||||
|
// assume that script in sigPops is the correct one, we just
|
||||||
|
// made it.
|
||||||
|
script := sigPops[len(sigPops)-1].data
|
||||||
|
|
||||||
|
// We already know this information somewhere up the stack.
|
||||||
|
class, addresses, nrequired, err :=
|
||||||
|
ExtractPkScriptAddrs(script, chainParams)
|
||||||
|
|
||||||
|
// regenerate scripts.
|
||||||
|
sigScript, _ := unparseScript(sigPops)
|
||||||
|
prevScript, _ := unparseScript(prevPops)
|
||||||
|
|
||||||
|
// Merge
|
||||||
|
mergedScript := mergeScripts(chainParams, tx, idx, script,
|
||||||
|
class, addresses, nrequired, sigScript, prevScript)
|
||||||
|
|
||||||
|
// Reappend the script and return the result.
|
||||||
|
builder := NewScriptBuilder()
|
||||||
|
builder.script = mergedScript
|
||||||
|
builder.AddData(script)
|
||||||
|
finalScript, _ := builder.Script()
|
||||||
|
return finalScript
|
||||||
|
case MultiSigTy:
|
||||||
|
return mergeMultiSig(tx, idx, addresses, nRequired, pkScript,
|
||||||
|
sigScript, prevScript)
|
||||||
|
|
||||||
|
// It doesn't actualy make sense to merge anything other than multiig
|
||||||
|
// and scripthash (because it could contain multisig). Everything else
|
||||||
|
// has either zero signature, can't be spent, or has a single signature
|
||||||
|
// which is either present or not. The other two cases are handled
|
||||||
|
// above. In the conflict case here we just assume the longest is
|
||||||
|
// correct (this matches behaviour of the reference implementation).
|
||||||
|
default:
|
||||||
|
if len(sigScript) > len(prevScript) {
|
||||||
|
return sigScript
|
||||||
|
}
|
||||||
|
return prevScript
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// mergeMultiSig combines the two signature scripts sigScript and prevScript
|
||||||
|
// that both provide signatures for pkScript in output idx of tx. addresses
|
||||||
|
// and nRequired should be the results from extracting the addresses from
|
||||||
|
// pkScript. Since this function is internal only we assume that the arguments
|
||||||
|
// have come from other functions internally and thus are all consistent with
|
||||||
|
// each other, behaviour is undefined if this contract is broken.
|
||||||
|
func mergeMultiSig(tx *wire.MsgTx, idx int, addresses []btcutil.Address,
|
||||||
|
nRequired int, pkScript, sigScript, prevScript []byte) []byte {
|
||||||
|
|
||||||
|
// This is an internal only function and we already parsed this script
|
||||||
|
// as ok for multisig (this is how we got here), so if this fails then
|
||||||
|
// all assumptions are broken and who knows which way is up?
|
||||||
|
pkPops, _ := parseScript(pkScript)
|
||||||
|
|
||||||
|
sigPops, err := parseScript(sigScript)
|
||||||
|
if err != nil || len(sigPops) == 0 {
|
||||||
|
return prevScript
|
||||||
|
}
|
||||||
|
|
||||||
|
prevPops, err := parseScript(prevScript)
|
||||||
|
if err != nil || len(prevPops) == 0 {
|
||||||
|
return sigScript
|
||||||
|
}
|
||||||
|
|
||||||
|
// Convenience function to avoid duplication.
|
||||||
|
extractSigs := func(pops []parsedOpcode, sigs [][]byte) [][]byte {
|
||||||
|
for _, pop := range pops {
|
||||||
|
if len(pop.data) != 0 {
|
||||||
|
sigs = append(sigs, pop.data)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
return sigs
|
||||||
|
}
|
||||||
|
|
||||||
|
possibleSigs := make([][]byte, 0, len(sigPops)+len(prevPops))
|
||||||
|
possibleSigs = extractSigs(sigPops, possibleSigs)
|
||||||
|
possibleSigs = extractSigs(prevPops, possibleSigs)
|
||||||
|
|
||||||
|
// Now we need to match the signatures to pubkeys, the only real way to
|
||||||
|
// do that is to try to verify them all and match it to the pubkey
|
||||||
|
// that verifies it. we then can go through the addresses in order
|
||||||
|
// to build our script. Anything that doesn't parse or doesn't verify we
|
||||||
|
// throw away.
|
||||||
|
addrToSig := make(map[string][]byte)
|
||||||
|
sigLoop:
|
||||||
|
for _, sig := range possibleSigs {
|
||||||
|
|
||||||
|
// can't have a valid signature that doesn't at least have a
|
||||||
|
// hashtype, in practise it is even longer than this. but
|
||||||
|
// that'll be checked next.
|
||||||
|
if len(sig) < 1 {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
tSig := sig[:len(sig)-1]
|
||||||
|
hashType := SigHashType(sig[len(sig)-1])
|
||||||
|
|
||||||
|
pSig, err := btcec.ParseDERSignature(tSig, btcec.S256())
|
||||||
|
if err != nil {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
|
||||||
|
// We have to do this each round since hash types may vary
|
||||||
|
// between signatures and so the hash will vary. We can,
|
||||||
|
// however, assume no sigs etc are in the script since that
|
||||||
|
// would make the transaction nonstandard and thus not
|
||||||
|
// MultiSigTy, so we just need to hash the full thing.
|
||||||
|
hash := calcScriptHash(pkPops, hashType, tx, idx)
|
||||||
|
|
||||||
|
for _, addr := range addresses {
|
||||||
|
// All multisig addresses should be pubkey addreses
|
||||||
|
// it is an error to call this internal function with
|
||||||
|
// bad input.
|
||||||
|
pkaddr := addr.(*btcutil.AddressPubKey)
|
||||||
|
|
||||||
|
pubKey := pkaddr.PubKey()
|
||||||
|
|
||||||
|
// If it matches we put it in the map. We only
|
||||||
|
// can take one signature per public key so if we
|
||||||
|
// already have one, we can throw this away.
|
||||||
|
if pSig.Verify(hash, pubKey) {
|
||||||
|
aStr := addr.EncodeAddress()
|
||||||
|
if _, ok := addrToSig[aStr]; !ok {
|
||||||
|
addrToSig[aStr] = sig
|
||||||
|
}
|
||||||
|
continue sigLoop
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// Extra opcode to handle the extra arg consumed (due to previous bugs
|
||||||
|
// in the reference implementation).
|
||||||
|
builder := NewScriptBuilder().AddOp(OP_FALSE)
|
||||||
|
doneSigs := 0
|
||||||
|
// This assumes that addresses are in the same order as in the script.
|
||||||
|
for _, addr := range addresses {
|
||||||
|
sig, ok := addrToSig[addr.EncodeAddress()]
|
||||||
|
if !ok {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
builder.AddData(sig)
|
||||||
|
doneSigs++
|
||||||
|
if doneSigs == nRequired {
|
||||||
|
break
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// padding for missing ones.
|
||||||
|
for i := doneSigs; i < nRequired; i++ {
|
||||||
|
builder.AddOp(OP_0)
|
||||||
|
}
|
||||||
|
|
||||||
|
script, _ := builder.Script()
|
||||||
|
return script
|
||||||
|
}
|
||||||
|
|
||||||
|
// KeyDB is an interface type provided to SignTxOutput, it encapsulates
|
||||||
|
// any user state required to get the private keys for an address.
|
||||||
|
type KeyDB interface {
|
||||||
|
GetKey(btcutil.Address) (*btcec.PrivateKey, bool, error)
|
||||||
|
}
|
||||||
|
|
||||||
|
// KeyClosure implements ScriptDB with a closure
|
||||||
|
type KeyClosure func(btcutil.Address) (*btcec.PrivateKey, bool, error)
|
||||||
|
|
||||||
|
// GetKey implements KeyDB by returning the result of calling the closure
|
||||||
|
func (kc KeyClosure) GetKey(address btcutil.Address) (*btcec.PrivateKey,
|
||||||
|
bool, error) {
|
||||||
|
return kc(address)
|
||||||
|
}
|
||||||
|
|
||||||
|
// ScriptDB is an interface type provided to SignTxOutput, it encapsulates any
|
||||||
|
// user state required to get the scripts for an pay-to-script-hash address.
|
||||||
|
type ScriptDB interface {
|
||||||
|
GetScript(btcutil.Address) ([]byte, error)
|
||||||
|
}
|
||||||
|
|
||||||
|
// ScriptClosure implements ScriptDB with a closure
|
||||||
|
type ScriptClosure func(btcutil.Address) ([]byte, error)
|
||||||
|
|
||||||
|
// GetScript implements ScriptDB by returning the result of calling the closure
|
||||||
|
func (sc ScriptClosure) GetScript(address btcutil.Address) ([]byte, error) {
|
||||||
|
return sc(address)
|
||||||
|
}
|
||||||
|
|
||||||
|
// SignTxOutput signs output idx of the given tx to resolve the script given in
|
||||||
|
// pkScript with a signature type of hashType. Any keys required will be
|
||||||
|
// looked up by calling getKey() with the string of the given address.
|
||||||
|
// Any pay-to-script-hash signatures will be similarly looked up by calling
|
||||||
|
// getScript. If previousScript is provided then the results in previousScript
|
||||||
|
// will be merged in a type-dependant manner with the newly generated.
|
||||||
|
// signature script.
|
||||||
|
func SignTxOutput(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int,
|
||||||
|
pkScript []byte, hashType SigHashType, kdb KeyDB, sdb ScriptDB,
|
||||||
|
previousScript []byte) ([]byte, error) {
|
||||||
|
|
||||||
|
sigScript, class, addresses, nrequired, err := sign(chainParams, tx,
|
||||||
|
idx, pkScript, hashType, kdb, sdb)
|
||||||
|
if err != nil {
|
||||||
|
return nil, err
|
||||||
|
}
|
||||||
|
|
||||||
|
if class == ScriptHashTy {
|
||||||
|
// TODO keep the sub addressed and pass down to merge.
|
||||||
|
realSigScript, _, _, _, err := sign(chainParams, tx, idx,
|
||||||
|
sigScript, hashType, kdb, sdb)
|
||||||
|
if err != nil {
|
||||||
|
return nil, err
|
||||||
|
}
|
||||||
|
|
||||||
|
// This is a bad thing. Append the p2sh script as the last
|
||||||
|
// push in the script.
|
||||||
|
builder := NewScriptBuilder()
|
||||||
|
builder.script = realSigScript
|
||||||
|
builder.AddData(sigScript)
|
||||||
|
|
||||||
|
sigScript, _ = builder.Script()
|
||||||
|
// TODO keep a copy of the script for merging.
|
||||||
|
}
|
||||||
|
|
||||||
|
// Merge scripts. with any previous data, if any.
|
||||||
|
mergedScript := mergeScripts(chainParams, tx, idx, pkScript, class,
|
||||||
|
addresses, nrequired, sigScript, previousScript)
|
||||||
|
return mergedScript, nil
|
||||||
|
}
|
||||||
1714
txscript/sign_test.go
Normal file
1714
txscript/sign_test.go
Normal file
File diff suppressed because it is too large
Load diff
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Reference in a new issue