From 5ed8799b451b3dba75a196fd53f3dafc462202ab Mon Sep 17 00:00:00 2001 From: div72 Date: Mon, 9 Oct 2023 00:08:11 +0300 Subject: [PATCH] script: use CScriptNum instead of CBigNum --- src/script.cpp | 46 +++++------- src/script.h | 193 +++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 204 insertions(+), 35 deletions(-) diff --git a/src/script.cpp b/src/script.cpp index 41cb6ba498..45d5e9000f 100644 --- a/src/script.cpp +++ b/src/script.cpp @@ -6,7 +6,6 @@ #include "script.h" #include #include "keystore.h" -#include "bignum.h" #include "key.h" #include "main.h" #include "random.h" @@ -26,20 +25,10 @@ bool CheckSig(vector vchSig, vector vchPubKey, CSc static const valtype vchFalse(0); static const valtype vchZero(0); static const valtype vchTrue(1, 1); -static const CBigNum bnZero(0); -static const CBigNum bnOne(1); -static const CBigNum bnFalse(0); -static const CBigNum bnTrue(1); -static const size_t nMaxNumSize = 4; - - -CBigNum CastToBigNum(const valtype& vch) -{ - if (vch.size() > nMaxNumSize) - throw runtime_error("CastToBigNum() : overflow"); - // Get rid of extra leading zeros - return CBigNum(CBigNum(vch).getvch()); -} +static const CScriptNum bnZero(0); +static const CScriptNum bnOne(1); +static const CScriptNum bnFalse(0); +static const CScriptNum bnTrue(1); bool CastToBool(const valtype& vch) { @@ -332,7 +321,6 @@ static bool IsCanonicalSignature(const valtype &vchSig) { bool EvalScript(vector >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, int nHashType) { - CAutoBN_CTX pctx; CScript::const_iterator pc = script.begin(); CScript::const_iterator pend = script.end(); CScript::const_iterator pbegincodehash = script.begin(); @@ -405,7 +393,7 @@ bool EvalScript(vector >& stack, const CScript& script, co case OP_16: { // ( -- value) - CBigNum bn((int)opcode - (int)(OP_1 - 1)); + CScriptNum bn((int)opcode - (int)(OP_1 - 1)); stack.push_back(bn.getvch()); } break; @@ -581,7 +569,7 @@ bool EvalScript(vector >& stack, const CScript& script, co case OP_DEPTH: { // -- stacksize - CBigNum bn(stack.size()); + CScriptNum bn(stack.size()); stack.push_back(bn.getvch()); } break; @@ -631,7 +619,7 @@ bool EvalScript(vector >& stack, const CScript& script, co // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn) if (stack.size() < 2) return false; - int n = CastToBigNum(stacktop(-1)).getint(); + int n = CScriptNum(stacktop(-1), false).getint(); popstack(stack); if (n < 0 || n >= (int)stack.size()) return false; @@ -678,7 +666,7 @@ bool EvalScript(vector >& stack, const CScript& script, co // (in -- in size) if (stack.size() < 1) return false; - CBigNum bn(stacktop(-1).size()); + CScriptNum bn(stacktop(-1).size()); stack.push_back(bn.getvch()); } break; @@ -725,7 +713,7 @@ bool EvalScript(vector >& stack, const CScript& script, co // (in -- out) if (stack.size() < 1) return false; - CBigNum bn = CastToBigNum(stacktop(-1)); + CScriptNum bn(stacktop(-1), false); switch (opcode) { case OP_1ADD: bn += bnOne; break; @@ -758,9 +746,9 @@ bool EvalScript(vector >& stack, const CScript& script, co // (x1 x2 -- out) if (stack.size() < 2) return false; - CBigNum bn1 = CastToBigNum(stacktop(-2)); - CBigNum bn2 = CastToBigNum(stacktop(-1)); - CBigNum bn; + CScriptNum bn1(stacktop(-2), false); + CScriptNum bn2(stacktop(-1), false); + CScriptNum bn(0); switch (opcode) { case OP_ADD: @@ -803,9 +791,9 @@ bool EvalScript(vector >& stack, const CScript& script, co // (x min max -- out) if (stack.size() < 3) return false; - CBigNum bn1 = CastToBigNum(stacktop(-3)); - CBigNum bn2 = CastToBigNum(stacktop(-2)); - CBigNum bn3 = CastToBigNum(stacktop(-1)); + CScriptNum bn1(stacktop(-3), false); + CScriptNum bn2(stacktop(-2), false); + CScriptNum bn3(stacktop(-1), false); bool fValue = (bn2 <= bn1 && bn1 < bn3); popstack(stack); popstack(stack); @@ -898,7 +886,7 @@ bool EvalScript(vector >& stack, const CScript& script, co if ((int)stack.size() < i) return false; - int nKeysCount = CastToBigNum(stacktop(-i)).getint(); + int nKeysCount = CScriptNum(stacktop(-i), false).getint(); if (nKeysCount < 0 || nKeysCount > 20) return false; nOpCount += nKeysCount; @@ -909,7 +897,7 @@ bool EvalScript(vector >& stack, const CScript& script, co if ((int)stack.size() < i) return false; - int nSigsCount = CastToBigNum(stacktop(-i)).getint(); + int nSigsCount = CScriptNum(stacktop(-i), false).getint(); if (nSigsCount < 0 || nSigsCount > nKeysCount) return false; int isig = ++i; diff --git a/src/script.h b/src/script.h index 51e55abd7e..5cf9feafe3 100644 --- a/src/script.h +++ b/src/script.h @@ -15,7 +15,6 @@ #include "keystore.h" -#include "bignum.h" #include "prevector.h" #include #include "wallet/ismine.h" @@ -246,11 +245,193 @@ enum opcodetype const char* GetOpName(opcodetype opcode); +class scriptnum_error : public std::runtime_error +{ +public: + explicit scriptnum_error(const std::string& str) : std::runtime_error(str) {} +}; + +class CScriptNum +{ +/** + * Numeric opcodes (OP_1ADD, etc) are restricted to operating on 4-byte integers. + * The semantics are subtle, though: operands must be in the range [-2^31 +1...2^31 -1], + * but results may overflow (and are valid as long as they are not used in a subsequent + * numeric operation). CScriptNum enforces those semantics by storing results as + * an int64 and allowing out-of-range values to be returned as a vector of bytes but + * throwing an exception if arithmetic is done or the result is interpreted as an integer. + */ +public: + + explicit CScriptNum(const int64_t& n) + { + m_value = n; + } + + static const size_t nDefaultMaxNumSize = 4; + + explicit CScriptNum(const std::vector& vch, bool fRequireMinimal, + const size_t nMaxNumSize = nDefaultMaxNumSize) + { + if (vch.size() > nMaxNumSize) { + throw scriptnum_error("script number overflow"); + } + if (fRequireMinimal && vch.size() > 0) { + // Check that the number is encoded with the minimum possible + // number of bytes. + // + // If the most-significant-byte - excluding the sign bit - is zero + // then we're not minimal. Note how this test also rejects the + // negative-zero encoding, 0x80. + if ((vch.back() & 0x7f) == 0) { + // One exception: if there's more than one byte and the most + // significant bit of the second-most-significant-byte is set + // it would conflict with the sign bit. An example of this case + // is +-255, which encode to 0xff00 and 0xff80 respectively. + // (big-endian). + if (vch.size() <= 1 || (vch[vch.size() - 2] & 0x80) == 0) { + throw scriptnum_error("non-minimally encoded script number"); + } + } + } + m_value = set_vch(vch); + } + + inline bool operator==(const int64_t& rhs) const { return m_value == rhs; } + inline bool operator!=(const int64_t& rhs) const { return m_value != rhs; } + inline bool operator<=(const int64_t& rhs) const { return m_value <= rhs; } + inline bool operator< (const int64_t& rhs) const { return m_value < rhs; } + inline bool operator>=(const int64_t& rhs) const { return m_value >= rhs; } + inline bool operator> (const int64_t& rhs) const { return m_value > rhs; } + + inline bool operator==(const CScriptNum& rhs) const { return operator==(rhs.m_value); } + inline bool operator!=(const CScriptNum& rhs) const { return operator!=(rhs.m_value); } + inline bool operator<=(const CScriptNum& rhs) const { return operator<=(rhs.m_value); } + inline bool operator< (const CScriptNum& rhs) const { return operator< (rhs.m_value); } + inline bool operator>=(const CScriptNum& rhs) const { return operator>=(rhs.m_value); } + inline bool operator> (const CScriptNum& rhs) const { return operator> (rhs.m_value); } + + inline CScriptNum operator+( const int64_t& rhs) const { return CScriptNum(m_value + rhs);} + inline CScriptNum operator-( const int64_t& rhs) const { return CScriptNum(m_value - rhs);} + inline CScriptNum operator+( const CScriptNum& rhs) const { return operator+(rhs.m_value); } + inline CScriptNum operator-( const CScriptNum& rhs) const { return operator-(rhs.m_value); } + + inline CScriptNum& operator+=( const CScriptNum& rhs) { return operator+=(rhs.m_value); } + inline CScriptNum& operator-=( const CScriptNum& rhs) { return operator-=(rhs.m_value); } + + inline CScriptNum operator&( const int64_t& rhs) const { return CScriptNum(m_value & rhs);} + inline CScriptNum operator&( const CScriptNum& rhs) const { return operator&(rhs.m_value); } + + inline CScriptNum& operator&=( const CScriptNum& rhs) { return operator&=(rhs.m_value); } + + inline CScriptNum operator-() const + { + assert(m_value != std::numeric_limits::min()); + return CScriptNum(-m_value); + } + + inline CScriptNum& operator=( const int64_t& rhs) + { + m_value = rhs; + return *this; + } + + inline CScriptNum& operator+=( const int64_t& rhs) + { + assert(rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits::max() - rhs) || + (rhs < 0 && m_value >= std::numeric_limits::min() - rhs)); + m_value += rhs; + return *this; + } + + inline CScriptNum& operator-=( const int64_t& rhs) + { + assert(rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits::min() + rhs) || + (rhs < 0 && m_value <= std::numeric_limits::max() + rhs)); + m_value -= rhs; + return *this; + } + + inline CScriptNum& operator&=( const int64_t& rhs) + { + m_value &= rhs; + return *this; + } + + int getint() const + { + if (m_value > std::numeric_limits::max()) + return std::numeric_limits::max(); + else if (m_value < std::numeric_limits::min()) + return std::numeric_limits::min(); + return m_value; + } + + int64_t GetInt64() const { return m_value; } + + std::vector getvch() const + { + return serialize(m_value); + } + + static std::vector serialize(const int64_t& value) + { + if(value == 0) + return std::vector(); + + std::vector result; + const bool neg = value < 0; + uint64_t absvalue = neg ? ~static_cast(value) + 1 : static_cast(value); + + while(absvalue) + { + result.push_back(absvalue & 0xff); + absvalue >>= 8; + } + +// - If the most significant byte is >= 0x80 and the value is positive, push a +// new zero-byte to make the significant byte < 0x80 again. + +// - If the most significant byte is >= 0x80 and the value is negative, push a +// new 0x80 byte that will be popped off when converting to an integral. + +// - If the most significant byte is < 0x80 and the value is negative, add +// 0x80 to it, since it will be subtracted and interpreted as a negative when +// converting to an integral. + + if (result.back() & 0x80) + result.push_back(neg ? 0x80 : 0); + else if (neg) + result.back() |= 0x80; + + return result; + } + +private: + static int64_t set_vch(const std::vector& vch) + { + if (vch.empty()) + return 0; + + int64_t result = 0; + for (size_t i = 0; i != vch.size(); ++i) + result |= static_cast(vch[i]) << 8*i; + + // If the input vector's most significant byte is 0x80, remove it from + // the result's msb and return a negative. + if (vch.back() & 0x80) + return -((int64_t)(result & ~(0x80ULL << (8 * (vch.size() - 1))))); + + return result; + } + + int64_t m_value; +}; inline std::string ValueString(const std::vector& vch) { if (vch.size() <= 4) - return strprintf("%d", CBigNum(vch).getint()); + return strprintf("%d", CScriptNum(vch, false).getint()); else return HexStr(vch); } @@ -269,7 +450,7 @@ class CScript : public CScriptBase } else { - CBigNum bn(n); + CScriptNum bn(n); *this << bn.getvch(); } return *this; @@ -283,7 +464,7 @@ class CScript : public CScriptBase } else { - CBigNum bn(n); + CScriptNum bn(n); *this << bn.getvch(); } return *this; @@ -334,7 +515,7 @@ class CScript : public CScriptBase explicit CScript(opcodetype b) { operator<<(b); } explicit CScript(const uint256& b) { operator<<(b); } - explicit CScript(const CBigNum& b) { operator<<(b); } + explicit CScript(const CScriptNum& b) { operator<<(b); } explicit CScript(const std::vector& b) { operator<<(b); } @@ -378,7 +559,7 @@ class CScript : public CScriptBase return (*this) << vchKey; } - CScript& operator<<(const CBigNum& b) + CScript& operator<<(const CScriptNum& b) { *this << b.getvch(); return *this;