src/script.h
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef H_BITCOIN_SCRIPT
#define H_BITCOIN_SCRIPT
#include <string>
#include <vector>
#include <stdint.h>
#include <boost/foreach.hpp>
#include <boost/variant.hpp>
#include "stealth.h"
#include "extkey.h"
#include "keystore.h"
#include "bignum.h"
#include "util.h"
typedef std::vector<unsigned char> valtype;
class CTransaction;
static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520; // bytes
static const unsigned int MAX_OP_RETURN_RELAY = 48; // bytes
template <typename T>
std::vector<unsigned char> ToByteVector(const T& in)
{
return std::vector<unsigned char>(in.begin(), in.end());
}
/** Signature hash types/flags */
enum
{
SIGHASH_ALL = 1,
SIGHASH_NONE = 2,
SIGHASH_SINGLE = 3,
SIGHASH_ANYONECANPAY = 0x80,
};
/** Script verification flags */
enum
{
SCRIPT_VERIFY_NONE = 0,
// Evaluate P2SH subscripts (softfork safe, BIP16).
SCRIPT_VERIFY_P2SH = (1U << 0),
SCRIPT_VERIFY_NULLDUMMY = (1U << 1), // verify dummy stack item consumed by CHECKMULTISIG is of zero-length
// Discourage use of NOPs reserved for upgrades (NOP1-10)
//
// Provided so that nodes can avoid accepting or mining transactions
// containing executed NOP's whose meaning may change after a soft-fork,
// thus rendering the script invalid; with this flag set executing
// discouraged NOPs fails the script. This verification flag will never be
// a mandatory flag applied to scripts in a block. NOPs that are not
// executed, e.g. within an unexecuted IF ENDIF block, are *not* rejected.
SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS = (1U << 2),
SCRIPT_VERIFY_STRICTENC = (1U << 3),
SCRIPT_VERIFY_NOCACHE = (1U << 4), // do not store results in signature cache (but do query it)
SCRIPT_VERIFY_ALLOW_EMPTY_SIG = (1U << 5),
SCRIPT_VERIFY_FIX_HASHTYPE = (1U << 6),
// Verify CHECKLOCKTIMEVERIFY (BIP65)
//
SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 7),
};
// Mandatory script verification flags that all new blocks must comply with for
// them to be valid. (but old blocks may not comply with)
//
// Failing one of these tests may trigger a DoS ban - see ConnectInputs() for
// details.
static const unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH |
SCRIPT_VERIFY_NULLDUMMY |
SCRIPT_VERIFY_STRICTENC |
SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
// Standard script verification flags that standard transactions will comply
// with. However scripts violating these flags may still be present in valid
// blocks and we must accept those blocks.
static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY_FLAGS |
SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS;
// For convenience, standard but not mandatory verify flags.
static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;
enum txnouttype
{
TX_NONSTANDARD,
// 'standard' transaction types:
TX_PUBKEY,
TX_PUBKEYHASH,
TX_SCRIPTHASH,
TX_MULTISIG,
TX_NULL_DATA,
};
class CNoDestination {
public:
friend bool operator==(const CNoDestination &a, const CNoDestination &b) { return true; }
friend bool operator<(const CNoDestination &a, const CNoDestination &b) { return true; }
};
/** A reference to a CScript: the Hash160 of its serialization */
class CScriptID : public uint160
{
public:
CScriptID() : uint160(0) { }
CScriptID(const CScript& in);
CScriptID(const uint160 &in) : uint160(in) { }
};
/** A txout script template with a specific destination. It is either:
* * CNoDestination: no destination set
* * CKeyID: TX_PUBKEYHASH destination
* * CScriptID: TX_SCRIPTHASH destination
* A CTxDestination is the internal data type encoded in a CBitcoinAddress
*/
typedef boost::variant<CNoDestination, CKeyID, CScriptID, CStealthAddress, CExtKeyPair> CTxDestination;
const char* GetTxnOutputType(txnouttype t);
/** Script opcodes */
enum opcodetype
{
// push value
OP_0 = 0x00,
OP_FALSE = OP_0,
OP_PUSHDATA1 = 0x4c,
OP_PUSHDATA2 = 0x4d,
OP_PUSHDATA4 = 0x4e,
OP_1NEGATE = 0x4f,
OP_RESERVED = 0x50,
OP_1 = 0x51,
OP_TRUE=OP_1,
OP_2 = 0x52,
OP_3 = 0x53,
OP_4 = 0x54,
OP_5 = 0x55,
OP_6 = 0x56,
OP_7 = 0x57,
OP_8 = 0x58,
OP_9 = 0x59,
OP_10 = 0x5a,
OP_11 = 0x5b,
OP_12 = 0x5c,
OP_13 = 0x5d,
OP_14 = 0x5e,
OP_15 = 0x5f,
OP_16 = 0x60,
// control
OP_NOP = 0x61,
OP_VER = 0x62,
OP_IF = 0x63,
OP_NOTIF = 0x64,
OP_VERIF = 0x65,
OP_VERNOTIF = 0x66,
OP_ELSE = 0x67,
OP_ENDIF = 0x68,
OP_VERIFY = 0x69,
OP_RETURN = 0x6a,
// stack ops
OP_TOALTSTACK = 0x6b,
OP_FROMALTSTACK = 0x6c,
OP_2DROP = 0x6d,
OP_2DUP = 0x6e,
OP_3DUP = 0x6f,
OP_2OVER = 0x70,
OP_2ROT = 0x71,
OP_2SWAP = 0x72,
OP_IFDUP = 0x73,
OP_DEPTH = 0x74,
OP_DROP = 0x75,
OP_DUP = 0x76,
OP_NIP = 0x77,
OP_OVER = 0x78,
OP_PICK = 0x79,
OP_ROLL = 0x7a,
OP_ROT = 0x7b,
OP_SWAP = 0x7c,
OP_TUCK = 0x7d,
// splice ops
OP_CAT = 0x7e,
OP_SUBSTR = 0x7f,
OP_LEFT = 0x80,
OP_RIGHT = 0x81,
OP_SIZE = 0x82,
// bit logic
OP_INVERT = 0x83,
OP_AND = 0x84,
OP_OR = 0x85,
OP_XOR = 0x86,
OP_EQUAL = 0x87,
OP_EQUALVERIFY = 0x88,
OP_RESERVED1 = 0x89,
OP_RESERVED2 = 0x8a,
// numeric
OP_1ADD = 0x8b,
OP_1SUB = 0x8c,
OP_2MUL = 0x8d,
OP_2DIV = 0x8e,
OP_NEGATE = 0x8f,
OP_ABS = 0x90,
OP_NOT = 0x91,
OP_0NOTEQUAL = 0x92,
OP_ADD = 0x93,
OP_SUB = 0x94,
OP_MUL = 0x95,
OP_DIV = 0x96,
OP_MOD = 0x97,
OP_LSHIFT = 0x98,
OP_RSHIFT = 0x99,
OP_BOOLAND = 0x9a,
OP_BOOLOR = 0x9b,
OP_NUMEQUAL = 0x9c,
OP_NUMEQUALVERIFY = 0x9d,
OP_NUMNOTEQUAL = 0x9e,
OP_LESSTHAN = 0x9f,
OP_GREATERTHAN = 0xa0,
OP_LESSTHANOREQUAL = 0xa1,
OP_GREATERTHANOREQUAL = 0xa2,
OP_MIN = 0xa3,
OP_MAX = 0xa4,
OP_WITHIN = 0xa5,
// crypto
OP_RIPEMD160 = 0xa6,
OP_SHA1 = 0xa7,
OP_SHA256 = 0xa8,
OP_HASH160 = 0xa9,
OP_HASH256 = 0xaa,
OP_CODESEPARATOR = 0xab,
OP_CHECKSIG = 0xac,
OP_CHECKSIGVERIFY = 0xad,
OP_CHECKMULTISIG = 0xae,
OP_CHECKMULTISIGVERIFY = 0xaf,
// expansion
OP_NOP1 = 0xb0,
OP_CHECKLOCKTIMEVERIFY = 0xb1,
OP_NOP2 = OP_CHECKLOCKTIMEVERIFY,
OP_NOP3 = 0xb2,
OP_NOP4 = 0xb3,
OP_NOP5 = 0xb4,
OP_NOP6 = 0xb5,
OP_NOP7 = 0xb6,
OP_NOP8 = 0xb7,
OP_NOP9 = 0xb8,
OP_ANON_MARKER = 0xb9, // OP_NOP10
// template matching params
OP_SMALLDATA = 0xf9,
OP_SMALLINTEGER = 0xfa,
OP_PUBKEYS = 0xfb,
OP_PUBKEYHASH = 0xfd,
OP_PUBKEY = 0xfe,
OP_INVALIDOPCODE = 0xff,
};
const char* GetOpName(opcodetype opcode);
inline std::string ValueString(const std::vector<unsigned char>& vch)
{
if (vch.size() <= 4)
return strprintf("%d", CBigNum(vch).getint());
else
return HexStr(vch);
}
inline std::string StackString(const std::vector<std::vector<unsigned char> >& vStack)
{
std::string str;
BOOST_FOREACH(const std::vector<unsigned char>& vch, vStack)
{
if (!str.empty())
str += " ";
str += ValueString(vch);
}
return str;
}
/** Serialized script, used inside transaction inputs and outputs */
class CScript : public std::vector<unsigned char>
{
protected:
CScript& push_int64(int64_t n)
{
if (n == -1 || (n >= 1 && n <= 16))
{
push_back(n + (OP_1 - 1));
}
else
{
CBigNum bn(n);
*this << bn.getvch();
}
return *this;
}
CScript& push_uint64(uint64_t n)
{
if (n >= 1 && n <= 16)
{
push_back(n + (OP_1 - 1));
}
else
{
CBigNum bn(n);
*this << bn.getvch();
}
return *this;
}
public:
CScript() { }
CScript(const CScript& b) : std::vector<unsigned char>(b.begin(), b.end()) { }
CScript(const_iterator pbegin, const_iterator pend) : std::vector<unsigned char>(pbegin, pend) { }
#ifndef _MSC_VER
CScript(const unsigned char* pbegin, const unsigned char* pend) : std::vector<unsigned char>(pbegin, pend) { }
#endif
CScript& operator+=(const CScript& b)
{
insert(end(), b.begin(), b.end());
return *this;
}
friend CScript operator+(const CScript& a, const CScript& b)
{
CScript ret = a;
ret += b;
return ret;
}
//explicit CScript(char b) is not portable. Use 'signed char' or 'unsigned char'.
explicit CScript(signed char b) { operator<<(b); }
explicit CScript(short b) { operator<<(b); }
explicit CScript(int b) { operator<<(b); }
explicit CScript(long b) { operator<<(b); }
explicit CScript(long long b) { operator<<(b); }
explicit CScript(unsigned char b) { operator<<(b); }
explicit CScript(unsigned int b) { operator<<(b); }
explicit CScript(unsigned short b) { operator<<(b); }
explicit CScript(unsigned long b) { operator<<(b); }
explicit CScript(unsigned long long b) { operator<<(b); }
explicit CScript(opcodetype b) { operator<<(b); }
explicit CScript(const uint256& b) { operator<<(b); }
explicit CScript(const CBigNum& b) { operator<<(b); }
explicit CScript(const std::vector<unsigned char>& b) { operator<<(b); }
//CScript& operator<<(char b) is not portable. Use 'signed char' or 'unsigned char'.
CScript& operator<<(signed char b) { return push_int64(b); }
CScript& operator<<(short b) { return push_int64(b); }
CScript& operator<<(int b) { return push_int64(b); }
CScript& operator<<(long b) { return push_int64(b); }
CScript& operator<<(long long b) { return push_int64(b); }
CScript& operator<<(unsigned char b) { return push_uint64(b); }
CScript& operator<<(unsigned int b) { return push_uint64(b); }
CScript& operator<<(unsigned short b) { return push_uint64(b); }
CScript& operator<<(unsigned long b) { return push_uint64(b); }
CScript& operator<<(unsigned long long b) { return push_uint64(b); }
CScript& operator<<(opcodetype opcode)
{
if (opcode < 0 || opcode > 0xff)
throw std::runtime_error("CScript::operator<<() : invalid opcode");
insert(end(), (unsigned char)opcode);
return *this;
}
CScript& operator<<(const uint160& b)
{
insert(end(), sizeof(b));
insert(end(), (unsigned char*)&b, (unsigned char*)&b + sizeof(b));
return *this;
}
CScript& operator<<(const uint256& b)
{
insert(end(), sizeof(b));
insert(end(), (unsigned char*)&b, (unsigned char*)&b + sizeof(b));
return *this;
}
CScript& operator<<(const CPubKey& key)
{
assert(key.size() < OP_PUSHDATA1);
insert(end(), (unsigned char)key.size());
insert(end(), key.begin(), key.end());
return *this;
}
CScript& operator<<(const CBigNum& b)
{
*this << b.getvch();
return *this;
}
CScript& operator<<(const std::vector<unsigned char>& b)
{
if (b.size() < OP_PUSHDATA1)
{
insert(end(), (unsigned char)b.size());
}
else if (b.size() <= 0xff)
{
insert(end(), OP_PUSHDATA1);
insert(end(), (unsigned char)b.size());
}
else if (b.size() <= 0xffff)
{
insert(end(), OP_PUSHDATA2);
unsigned short nSize = b.size();
insert(end(), (unsigned char*)&nSize, (unsigned char*)&nSize + sizeof(nSize));
}
else
{
insert(end(), OP_PUSHDATA4);
unsigned int nSize = b.size();
insert(end(), (unsigned char*)&nSize, (unsigned char*)&nSize + sizeof(nSize));
}
insert(end(), b.begin(), b.end());
return *this;
}
CScript& operator<<(const CScript& b)
{
// I'm not sure if this should push the script or concatenate scripts.
// If there's ever a use for pushing a script onto a script, delete this member fn
assert(!"Warning: Pushing a CScript onto a CScript with << is probably not intended, use + to concatenate!");
return *this;
}
bool GetOp(iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet)
{
// Wrapper so it can be called with either iterator or const_iterator
const_iterator pc2 = pc;
bool fRet = GetOp2(pc2, opcodeRet, &vchRet);
pc = begin() + (pc2 - begin());
return fRet;
}
bool GetOp(iterator& pc, opcodetype& opcodeRet)
{
const_iterator pc2 = pc;
bool fRet = GetOp2(pc2, opcodeRet, NULL);
pc = begin() + (pc2 - begin());
return fRet;
}
bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
{
return GetOp2(pc, opcodeRet, &vchRet);
}
bool GetOp(const_iterator& pc, opcodetype& opcodeRet) const
{
return GetOp2(pc, opcodeRet, NULL);
}
bool GetOp2(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>* pvchRet) const
{
opcodeRet = OP_INVALIDOPCODE;
if (pvchRet)
pvchRet->clear();
if (pc >= end())
return false;
// Read instruction
if (end() - pc < 1)
return false;
unsigned int opcode = *pc++;
// Immediate operand
if (opcode <= OP_PUSHDATA4)
{
unsigned int nSize;
if (opcode < OP_PUSHDATA1)
{
nSize = opcode;
}
else if (opcode == OP_PUSHDATA1)
{
if (end() - pc < 1)
return false;
nSize = *pc++;
}
else if (opcode == OP_PUSHDATA2)
{
if (end() - pc < 2)
return false;
nSize = 0;
memcpy(&nSize, &pc[0], 2);
pc += 2;
}
else if (opcode == OP_PUSHDATA4)
{
if (end() - pc < 4)
return false;
memcpy(&nSize, &pc[0], 4);
pc += 4;
}
if (end() - pc < 0 || (unsigned int)(end() - pc) < nSize)
return false;
if (pvchRet)
pvchRet->assign(pc, pc + nSize);
pc += nSize;
}
opcodeRet = (opcodetype)opcode;
return true;
}
// Encode/decode small integers:
static int DecodeOP_N(opcodetype opcode)
{
if (opcode == OP_0)
return 0;
assert(opcode >= OP_1 && opcode <= OP_16);
return (int)opcode - (int)(OP_1 - 1);
}
static opcodetype EncodeOP_N(int n)
{
assert(n >= 0 && n <= 16);
if (n == 0)
return OP_0;
return (opcodetype)(OP_1+n-1);
}
int FindAndDelete(const CScript& b)
{
int nFound = 0;
if (b.empty())
return nFound;
iterator pc = begin();
opcodetype opcode;
do
{
while (end() - pc >= (long)b.size() && memcmp(&pc[0], &b[0], b.size()) == 0)
{
erase(pc, pc + b.size());
++nFound;
}
}
while (GetOp(pc, opcode));
return nFound;
}
int Find(opcodetype op) const
{
int nFound = 0;
opcodetype opcode;
for (const_iterator pc = begin(); pc != end() && GetOp(pc, opcode);)
if (opcode == op)
++nFound;
return nFound;
}
// Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
// as 20 sigops. With pay-to-script-hash, that changed:
// CHECKMULTISIGs serialized in scriptSigs are
// counted more accurately, assuming they are of the form
// ... OP_N CHECKMULTISIG ...
unsigned int GetSigOpCount(bool fAccurate) const;
// Accurately count sigOps, including sigOps in
// pay-to-script-hash transactions:
unsigned int GetSigOpCount(const CScript& scriptSig) const;
bool IsPayToScriptHash() const;
// Called by IsStandardTx and P2SH VerifyScript (which makes it consensus-critical).
bool IsPushOnly() const
{
const_iterator pc = begin();
while (pc < end())
{
opcodetype opcode;
if (!GetOp(pc, opcode))
return false;
if (opcode > OP_16)
return false;
}
return true;
}
// Called by IsStandardTx.
bool HasCanonicalPushes() const;
void SetDestination(const CTxDestination& address);
void SetMultisig(int nRequired, const std::vector<CPubKey>& keys);
std::string ToString(bool fShort=false) const
{
std::string str;
opcodetype opcode;
std::vector<unsigned char> vch;
const_iterator pc = begin();
while (pc < end())
{
if (!str.empty())
str += " ";
if (!GetOp(pc, opcode, vch))
{
str += "[error]";
return str;
}
if (0 <= opcode && opcode <= OP_PUSHDATA4)
str += fShort? ValueString(vch).substr(0, 10) : ValueString(vch);
else
str += GetOpName(opcode);
}
return str;
}
CScriptID GetID() const
{
return CScriptID(Hash160(*this));
}
void clear()
{
// The default std::vector::clear() does not release memory.
std::vector<unsigned char>().swap(*this);
}
};
/** Compact serializer for scripts.
*
* It detects common cases and encodes them much more efficiently.
* 3 special cases are defined:
* * Pay to pubkey hash (encoded as 21 bytes)
* * Pay to script hash (encoded as 21 bytes)
* * Pay to pubkey starting with 0x02, 0x03 or 0x04 (encoded as 33 bytes)
*
* Other scripts up to 121 bytes require 1 byte + script length. Above
* that, scripts up to 16505 bytes require 2 bytes + script length.
*/
class CScriptCompressor
{
private:
// make this static for now (there are only 6 special scripts defined)
// this can potentially be extended together with a new nVersion for
// transactions, in which case this value becomes dependent on nVersion
// and nHeight of the enclosing transaction.
static const unsigned int nSpecialScripts = 6;
CScript &script;
protected:
// These check for scripts for which a special case with a shorter encoding is defined.
// They are implemented separately from the CScript test, as these test for exact byte
// sequence correspondences, and are more strict. For example, IsToPubKey also verifies
// whether the public key is valid (as invalid ones cannot be represented in compressed
// form).
bool IsToKeyID(CKeyID &hash) const;
bool IsToScriptID(CScriptID &hash) const;
bool IsToPubKey(CPubKey &pubkey) const;
bool Compress(std::vector<unsigned char> &out) const;
unsigned int GetSpecialSize(unsigned int nSize) const;
bool Decompress(unsigned int nSize, const std::vector<unsigned char> &out);
public:
CScriptCompressor(CScript &scriptIn) : script(scriptIn) { }
unsigned int GetSerializeSize(int nType, int nVersion) const {
std::vector<unsigned char> compr;
if (Compress(compr))
return compr.size();
unsigned int nSize = script.size() + nSpecialScripts;
return script.size() + VARINT(nSize).GetSerializeSize(nType, nVersion);
}
template<typename Stream>
void Serialize(Stream &s, int nType, int nVersion) const {
std::vector<unsigned char> compr;
if (Compress(compr)) {
s << CFlatData(&compr[0], &compr[compr.size()]);
return;
}
unsigned int nSize = script.size() + nSpecialScripts;
s << VARINT(nSize);
s << CFlatData(&script[0], &script[script.size()]);
}
template<typename Stream>
void Unserialize(Stream &s, int nType, int nVersion) {
unsigned int nSize;
s >> VARINT(nSize);
if (nSize < nSpecialScripts) {
std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00);
s >> REF(CFlatData(&vch[0], &vch[vch.size()]));
Decompress(nSize, vch);
return;
}
nSize -= nSpecialScripts;
script.resize(nSize);
s >> REF(CFlatData(&script[0], &script[script.size()]));
}
};
bool IsDERSignature(const valtype &vchSig, bool haveHashType = true);
bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType);
bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::vector<unsigned char> >& vSolutionsRet);
int ScriptSigArgsExpected(txnouttype t, const std::vector<std::vector<unsigned char> >& vSolutions);
bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType);
void ExtractAffectedKeys(const CKeyStore &keystore, const CScript& scriptPubKey, std::vector<CKeyID> &vKeys);
bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet);
bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<CTxDestination>& addressRet, int& nRequiredRet);
bool SignSignature(const CKeyStore& keystore, const CScript& fromPubKey, CTransaction& txTo, unsigned int nIn, int nHashType=SIGHASH_ALL);
bool SignSignature(const CKeyStore& keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType=SIGHASH_ALL);
bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CTransaction& txTo, unsigned int nIn,
unsigned int flags, int nHashType);
bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType);
// Given two sets of signatures for scriptPubKey, possibly with OP_0 placeholders,
// combine them intelligently and return the result.
CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsigned int nIn, const CScript& scriptSig1, const CScript& scriptSig2);
CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys);
#endif