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bitcoin-bitcoin-core/src/scriptutils.cpp
jtimon da03e6ed7c Separate script/interpreter
2014-09-08 20:21:33 +02:00

733 lines
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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "scriptutils.h"
#include "core.h"
#include "key.h"
#include "keystore.h"
#include "uint256.h"
#include "util.h"
#include <boost/foreach.hpp>
using namespace std;
typedef vector<unsigned char> valtype;
const char* GetTxnOutputType(txnouttype t)
{
switch (t)
{
case TX_NONSTANDARD: return "nonstandard";
case TX_PUBKEY: return "pubkey";
case TX_PUBKEYHASH: return "pubkeyhash";
case TX_SCRIPTHASH: return "scripthash";
case TX_MULTISIG: return "multisig";
case TX_NULL_DATA: return "nulldata";
}
return NULL;
}
//
// Return public keys or hashes from scriptPubKey, for 'standard' transaction types.
//
bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsigned char> >& vSolutionsRet)
{
// Templates
static multimap<txnouttype, CScript> mTemplates;
if (mTemplates.empty())
{
// Standard tx, sender provides pubkey, receiver adds signature
mTemplates.insert(make_pair(TX_PUBKEY, CScript() << OP_PUBKEY << OP_CHECKSIG));
// Bitcoin address tx, sender provides hash of pubkey, receiver provides signature and pubkey
mTemplates.insert(make_pair(TX_PUBKEYHASH, CScript() << OP_DUP << OP_HASH160 << OP_PUBKEYHASH << OP_EQUALVERIFY << OP_CHECKSIG));
// Sender provides N pubkeys, receivers provides M signatures
mTemplates.insert(make_pair(TX_MULTISIG, CScript() << OP_SMALLINTEGER << OP_PUBKEYS << OP_SMALLINTEGER << OP_CHECKMULTISIG));
// Empty, provably prunable, data-carrying output
if (GetBoolArg("-datacarrier", true))
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN << OP_SMALLDATA));
mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN));
}
// Shortcut for pay-to-script-hash, which are more constrained than the other types:
// it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
if (scriptPubKey.IsPayToScriptHash())
{
typeRet = TX_SCRIPTHASH;
vector<unsigned char> hashBytes(scriptPubKey.begin()+2, scriptPubKey.begin()+22);
vSolutionsRet.push_back(hashBytes);
return true;
}
// Scan templates
const CScript& script1 = scriptPubKey;
BOOST_FOREACH(const PAIRTYPE(txnouttype, CScript)& tplate, mTemplates)
{
const CScript& script2 = tplate.second;
vSolutionsRet.clear();
opcodetype opcode1, opcode2;
vector<unsigned char> vch1, vch2;
// Compare
CScript::const_iterator pc1 = script1.begin();
CScript::const_iterator pc2 = script2.begin();
while (true)
{
if (pc1 == script1.end() && pc2 == script2.end())
{
// Found a match
typeRet = tplate.first;
if (typeRet == TX_MULTISIG)
{
// Additional checks for TX_MULTISIG:
unsigned char m = vSolutionsRet.front()[0];
unsigned char n = vSolutionsRet.back()[0];
if (m < 1 || n < 1 || m > n || vSolutionsRet.size()-2 != n)
return false;
}
return true;
}
if (!script1.GetOp(pc1, opcode1, vch1))
break;
if (!script2.GetOp(pc2, opcode2, vch2))
break;
// Template matching opcodes:
if (opcode2 == OP_PUBKEYS)
{
while (vch1.size() >= 33 && vch1.size() <= 65)
{
vSolutionsRet.push_back(vch1);
if (!script1.GetOp(pc1, opcode1, vch1))
break;
}
if (!script2.GetOp(pc2, opcode2, vch2))
break;
// Normal situation is to fall through
// to other if/else statements
}
if (opcode2 == OP_PUBKEY)
{
if (vch1.size() < 33 || vch1.size() > 65)
break;
vSolutionsRet.push_back(vch1);
}
else if (opcode2 == OP_PUBKEYHASH)
{
if (vch1.size() != sizeof(uint160))
break;
vSolutionsRet.push_back(vch1);
}
else if (opcode2 == OP_SMALLINTEGER)
{ // Single-byte small integer pushed onto vSolutions
if (opcode1 == OP_0 ||
(opcode1 >= OP_1 && opcode1 <= OP_16))
{
char n = (char)CScript::DecodeOP_N(opcode1);
vSolutionsRet.push_back(valtype(1, n));
}
else
break;
}
else if (opcode2 == OP_SMALLDATA)
{
// small pushdata, <= MAX_OP_RETURN_RELAY bytes
if (vch1.size() > MAX_OP_RETURN_RELAY)
break;
}
else if (opcode1 != opcode2 || vch1 != vch2)
{
// Others must match exactly
break;
}
}
}
vSolutionsRet.clear();
typeRet = TX_NONSTANDARD;
return false;
}
bool Sign1(const CKeyID& address, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
{
CKey key;
if (!keystore.GetKey(address, key))
return false;
vector<unsigned char> vchSig;
if (!key.Sign(hash, vchSig))
return false;
vchSig.push_back((unsigned char)nHashType);
scriptSigRet << vchSig;
return true;
}
bool SignN(const vector<valtype>& multisigdata, const CKeyStore& keystore, uint256 hash, int nHashType, CScript& scriptSigRet)
{
int nSigned = 0;
int nRequired = multisigdata.front()[0];
for (unsigned int i = 1; i < multisigdata.size()-1 && nSigned < nRequired; i++)
{
const valtype& pubkey = multisigdata[i];
CKeyID keyID = CPubKey(pubkey).GetID();
if (Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
++nSigned;
}
return nSigned==nRequired;
}
//
// Sign scriptPubKey with private keys stored in keystore, given transaction hash and hash type.
// Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed),
// unless whichTypeRet is TX_SCRIPTHASH, in which case scriptSigRet is the redemption script.
// Returns false if scriptPubKey could not be completely satisfied.
//
bool Solver(const CKeyStore& keystore, const CScript& scriptPubKey, uint256 hash, int nHashType,
CScript& scriptSigRet, txnouttype& whichTypeRet)
{
scriptSigRet.clear();
vector<valtype> vSolutions;
if (!Solver(scriptPubKey, whichTypeRet, vSolutions))
return false;
CKeyID keyID;
switch (whichTypeRet)
{
case TX_NONSTANDARD:
case TX_NULL_DATA:
return false;
case TX_PUBKEY:
keyID = CPubKey(vSolutions[0]).GetID();
return Sign1(keyID, keystore, hash, nHashType, scriptSigRet);
case TX_PUBKEYHASH:
keyID = CKeyID(uint160(vSolutions[0]));
if (!Sign1(keyID, keystore, hash, nHashType, scriptSigRet))
return false;
else
{
CPubKey vch;
keystore.GetPubKey(keyID, vch);
scriptSigRet << vch;
}
return true;
case TX_SCRIPTHASH:
return keystore.GetCScript(uint160(vSolutions[0]), scriptSigRet);
case TX_MULTISIG:
scriptSigRet << OP_0; // workaround CHECKMULTISIG bug
return (SignN(vSolutions, keystore, hash, nHashType, scriptSigRet));
}
return false;
}
int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned char> >& vSolutions)
{
switch (t)
{
case TX_NONSTANDARD:
case TX_NULL_DATA:
return -1;
case TX_PUBKEY:
return 1;
case TX_PUBKEYHASH:
return 2;
case TX_MULTISIG:
if (vSolutions.size() < 1 || vSolutions[0].size() < 1)
return -1;
return vSolutions[0][0] + 1;
case TX_SCRIPTHASH:
return 1; // doesn't include args needed by the script
}
return -1;
}
bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
{
vector<valtype> vSolutions;
if (!Solver(scriptPubKey, whichType, vSolutions))
return false;
if (whichType == TX_MULTISIG)
{
unsigned char m = vSolutions.front()[0];
unsigned char n = vSolutions.back()[0];
// Support up to x-of-3 multisig txns as standard
if (n < 1 || n > 3)
return false;
if (m < 1 || m > n)
return false;
}
return whichType != TX_NONSTANDARD;
}
unsigned int HaveKeys(const vector<valtype>& pubkeys, const CKeyStore& keystore)
{
unsigned int nResult = 0;
BOOST_FOREACH(const valtype& pubkey, pubkeys)
{
CKeyID keyID = CPubKey(pubkey).GetID();
if (keystore.HaveKey(keyID))
++nResult;
}
return nResult;
}
isminetype IsMine(const CKeyStore &keystore, const CTxDestination& dest)
{
CScript script;
script.SetDestination(dest);
return IsMine(keystore, script);
}
isminetype IsMine(const CKeyStore &keystore, const CScript& scriptPubKey)
{
vector<valtype> vSolutions;
txnouttype whichType;
if (!Solver(scriptPubKey, whichType, vSolutions)) {
if (keystore.HaveWatchOnly(scriptPubKey))
return ISMINE_WATCH_ONLY;
return ISMINE_NO;
}
CKeyID keyID;
switch (whichType)
{
case TX_NONSTANDARD:
case TX_NULL_DATA:
break;
case TX_PUBKEY:
keyID = CPubKey(vSolutions[0]).GetID();
if (keystore.HaveKey(keyID))
return ISMINE_SPENDABLE;
break;
case TX_PUBKEYHASH:
keyID = CKeyID(uint160(vSolutions[0]));
if (keystore.HaveKey(keyID))
return ISMINE_SPENDABLE;
break;
case TX_SCRIPTHASH:
{
CScriptID scriptID = CScriptID(uint160(vSolutions[0]));
CScript subscript;
if (keystore.GetCScript(scriptID, subscript)) {
isminetype ret = IsMine(keystore, subscript);
if (ret == ISMINE_SPENDABLE)
return ret;
}
break;
}
case TX_MULTISIG:
{
// Only consider transactions "mine" if we own ALL the
// keys involved. multi-signature transactions that are
// partially owned (somebody else has a key that can spend
// them) enable spend-out-from-under-you attacks, especially
// in shared-wallet situations.
vector<valtype> keys(vSolutions.begin()+1, vSolutions.begin()+vSolutions.size()-1);
if (HaveKeys(keys, keystore) == keys.size())
return ISMINE_SPENDABLE;
break;
}
}
if (keystore.HaveWatchOnly(scriptPubKey))
return ISMINE_WATCH_ONLY;
return ISMINE_NO;
}
bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet)
{
vector<valtype> vSolutions;
txnouttype whichType;
if (!Solver(scriptPubKey, whichType, vSolutions))
return false;
if (whichType == TX_PUBKEY)
{
addressRet = CPubKey(vSolutions[0]).GetID();
return true;
}
else if (whichType == TX_PUBKEYHASH)
{
addressRet = CKeyID(uint160(vSolutions[0]));
return true;
}
else if (whichType == TX_SCRIPTHASH)
{
addressRet = CScriptID(uint160(vSolutions[0]));
return true;
}
// Multisig txns have more than one address...
return false;
}
bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, vector<CTxDestination>& addressRet, int& nRequiredRet)
{
addressRet.clear();
typeRet = TX_NONSTANDARD;
vector<valtype> vSolutions;
if (!Solver(scriptPubKey, typeRet, vSolutions))
return false;
if (typeRet == TX_NULL_DATA){
// This is data, not addresses
return false;
}
if (typeRet == TX_MULTISIG)
{
nRequiredRet = vSolutions.front()[0];
for (unsigned int i = 1; i < vSolutions.size()-1; i++)
{
CTxDestination address = CPubKey(vSolutions[i]).GetID();
addressRet.push_back(address);
}
}
else
{
nRequiredRet = 1;
CTxDestination address;
if (!ExtractDestination(scriptPubKey, address))
return false;
addressRet.push_back(address);
}
return true;
}
class CAffectedKeysVisitor : public boost::static_visitor<void> {
private:
const CKeyStore &keystore;
std::vector<CKeyID> &vKeys;
public:
CAffectedKeysVisitor(const CKeyStore &keystoreIn, std::vector<CKeyID> &vKeysIn) : keystore(keystoreIn), vKeys(vKeysIn) {}
void Process(const CScript &script) {
txnouttype type;
std::vector<CTxDestination> vDest;
int nRequired;
if (ExtractDestinations(script, type, vDest, nRequired)) {
BOOST_FOREACH(const CTxDestination &dest, vDest)
boost::apply_visitor(*this, dest);
}
}
void operator()(const CKeyID &keyId) {
if (keystore.HaveKey(keyId))
vKeys.push_back(keyId);
}
void operator()(const CScriptID &scriptId) {
CScript script;
if (keystore.GetCScript(scriptId, script))
Process(script);
}
void operator()(const CNoDestination &none) {}
};
void ExtractAffectedKeys(const CKeyStore &keystore, const CScript& scriptPubKey, std::vector<CKeyID> &vKeys) {
CAffectedKeysVisitor(keystore, vKeys).Process(scriptPubKey);
}
bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
{
assert(nIn < txTo.vin.size());
CTxIn& txin = txTo.vin[nIn];
// Leave out the signature from the hash, since a signature can't sign itself.
// The checksig op will also drop the signatures from its hash.
uint256 hash = SignatureHash(fromPubKey, txTo, nIn, nHashType);
txnouttype whichType;
if (!Solver(keystore, fromPubKey, hash, nHashType, txin.scriptSig, whichType))
return false;
if (whichType == TX_SCRIPTHASH)
{
// Solver returns the subscript that need to be evaluated;
// the final scriptSig is the signatures from that
// and then the serialized subscript:
CScript subscript = txin.scriptSig;
// Recompute txn hash using subscript in place of scriptPubKey:
uint256 hash2 = SignatureHash(subscript, txTo, nIn, nHashType);
txnouttype subType;
bool fSolved =
Solver(keystore, subscript, hash2, nHashType, txin.scriptSig, subType) && subType != TX_SCRIPTHASH;
// Append serialized subscript whether or not it is completely signed:
txin.scriptSig << static_cast<valtype>(subscript);
if (!fSolved) return false;
}
// Test solution
return VerifyScript(txin.scriptSig, fromPubKey, txTo, nIn, STANDARD_SCRIPT_VERIFY_FLAGS, 0);
}
bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
{
assert(nIn < txTo.vin.size());
CTxIn& txin = txTo.vin[nIn];
assert(txin.prevout.n < txFrom.vout.size());
const CTxOut& txout = txFrom.vout[txin.prevout.n];
return SignSignature(keystore, txout.scriptPubKey, txTo, nIn, nHashType);
}
static CScript PushAll(const vector<valtype>& values)
{
CScript result;
BOOST_FOREACH(const valtype& v, values)
result << v;
return result;
}
static CScript CombineMultisig(CScript scriptPubKey, const CMutableTransaction& txTo, unsigned int nIn,
const vector<valtype>& vSolutions,
vector<valtype>& sigs1, vector<valtype>& sigs2)
{
// Combine all the signatures we've got:
set<valtype> allsigs;
BOOST_FOREACH(const valtype& v, sigs1)
{
if (!v.empty())
allsigs.insert(v);
}
BOOST_FOREACH(const valtype& v, sigs2)
{
if (!v.empty())
allsigs.insert(v);
}
// Build a map of pubkey -> signature by matching sigs to pubkeys:
assert(vSolutions.size() > 1);
unsigned int nSigsRequired = vSolutions.front()[0];
unsigned int nPubKeys = vSolutions.size()-2;
map<valtype, valtype> sigs;
BOOST_FOREACH(const valtype& sig, allsigs)
{
for (unsigned int i = 0; i < nPubKeys; i++)
{
const valtype& pubkey = vSolutions[i+1];
if (sigs.count(pubkey))
continue; // Already got a sig for this pubkey
if (CheckSig(sig, pubkey, scriptPubKey, txTo, nIn, 0, 0))
{
sigs[pubkey] = sig;
break;
}
}
}
// Now build a merged CScript:
unsigned int nSigsHave = 0;
CScript result; result << OP_0; // pop-one-too-many workaround
for (unsigned int i = 0; i < nPubKeys && nSigsHave < nSigsRequired; i++)
{
if (sigs.count(vSolutions[i+1]))
{
result << sigs[vSolutions[i+1]];
++nSigsHave;
}
}
// Fill any missing with OP_0:
for (unsigned int i = nSigsHave; i < nSigsRequired; i++)
result << OP_0;
return result;
}
static CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
const txnouttype txType, const vector<valtype>& vSolutions,
vector<valtype>& sigs1, vector<valtype>& sigs2)
{
switch (txType)
{
case TX_NONSTANDARD:
case TX_NULL_DATA:
// Don't know anything about this, assume bigger one is correct:
if (sigs1.size() >= sigs2.size())
return PushAll(sigs1);
return PushAll(sigs2);
case TX_PUBKEY:
case TX_PUBKEYHASH:
// Signatures are bigger than placeholders or empty scripts:
if (sigs1.empty() || sigs1[0].empty())
return PushAll(sigs2);
return PushAll(sigs1);
case TX_SCRIPTHASH:
if (sigs1.empty() || sigs1.back().empty())
return PushAll(sigs2);
else if (sigs2.empty() || sigs2.back().empty())
return PushAll(sigs1);
else
{
// Recur to combine:
valtype spk = sigs1.back();
CScript pubKey2(spk.begin(), spk.end());
txnouttype txType2;
vector<vector<unsigned char> > vSolutions2;
Solver(pubKey2, txType2, vSolutions2);
sigs1.pop_back();
sigs2.pop_back();
CScript result = CombineSignatures(pubKey2, txTo, nIn, txType2, vSolutions2, sigs1, sigs2);
result << spk;
return result;
}
case TX_MULTISIG:
return CombineMultisig(scriptPubKey, txTo, nIn, vSolutions, sigs1, sigs2);
}
return CScript();
}
CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn,
const CScript& scriptSig1, const CScript& scriptSig2)
{
txnouttype txType;
vector<vector<unsigned char> > vSolutions;
Solver(scriptPubKey, txType, vSolutions);
vector<valtype> stack1;
EvalScript(stack1, scriptSig1, CTransaction(), 0, SCRIPT_VERIFY_STRICTENC, 0);
vector<valtype> stack2;
EvalScript(stack2, scriptSig2, CTransaction(), 0, SCRIPT_VERIFY_STRICTENC, 0);
return CombineSignatures(scriptPubKey, txTo, nIn, txType, vSolutions, stack1, stack2);
}
bool CScriptCompressor::IsToKeyID(CKeyID &hash) const
{
if (script.size() == 25 && script[0] == OP_DUP && script[1] == OP_HASH160
&& script[2] == 20 && script[23] == OP_EQUALVERIFY
&& script[24] == OP_CHECKSIG) {
memcpy(&hash, &script[3], 20);
return true;
}
return false;
}
bool CScriptCompressor::IsToScriptID(CScriptID &hash) const
{
if (script.size() == 23 && script[0] == OP_HASH160 && script[1] == 20
&& script[22] == OP_EQUAL) {
memcpy(&hash, &script[2], 20);
return true;
}
return false;
}
bool CScriptCompressor::IsToPubKey(CPubKey &pubkey) const
{
if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG
&& (script[1] == 0x02 || script[1] == 0x03)) {
pubkey.Set(&script[1], &script[34]);
return true;
}
if (script.size() == 67 && script[0] == 65 && script[66] == OP_CHECKSIG
&& script[1] == 0x04) {
pubkey.Set(&script[1], &script[66]);
return pubkey.IsFullyValid(); // if not fully valid, a case that would not be compressible
}
return false;
}
bool CScriptCompressor::Compress(std::vector<unsigned char> &out) const
{
CKeyID keyID;
if (IsToKeyID(keyID)) {
out.resize(21);
out[0] = 0x00;
memcpy(&out[1], &keyID, 20);
return true;
}
CScriptID scriptID;
if (IsToScriptID(scriptID)) {
out.resize(21);
out[0] = 0x01;
memcpy(&out[1], &scriptID, 20);
return true;
}
CPubKey pubkey;
if (IsToPubKey(pubkey)) {
out.resize(33);
memcpy(&out[1], &pubkey[1], 32);
if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
out[0] = pubkey[0];
return true;
} else if (pubkey[0] == 0x04) {
out[0] = 0x04 | (pubkey[64] & 0x01);
return true;
}
}
return false;
}
unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
{
if (nSize == 0 || nSize == 1)
return 20;
if (nSize == 2 || nSize == 3 || nSize == 4 || nSize == 5)
return 32;
return 0;
}
bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigned char> &in)
{
switch(nSize) {
case 0x00:
script.resize(25);
script[0] = OP_DUP;
script[1] = OP_HASH160;
script[2] = 20;
memcpy(&script[3], &in[0], 20);
script[23] = OP_EQUALVERIFY;
script[24] = OP_CHECKSIG;
return true;
case 0x01:
script.resize(23);
script[0] = OP_HASH160;
script[1] = 20;
memcpy(&script[2], &in[0], 20);
script[22] = OP_EQUAL;
return true;
case 0x02:
case 0x03:
script.resize(35);
script[0] = 33;
script[1] = nSize;
memcpy(&script[2], &in[0], 32);
script[34] = OP_CHECKSIG;
return true;
case 0x04:
case 0x05:
unsigned char vch[33] = {};
vch[0] = nSize - 2;
memcpy(&vch[1], &in[0], 32);
CPubKey pubkey(&vch[0], &vch[33]);
if (!pubkey.Decompress())
return false;
assert(pubkey.size() == 65);
script.resize(67);
script[0] = 65;
memcpy(&script[1], pubkey.begin(), 65);
script[66] = OP_CHECKSIG;
return true;
}
return false;
}
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