diff options
Diffstat (limited to 'src/script/interpreter.cpp')
-rw-r--r-- | src/script/interpreter.cpp | 396 |
1 files changed, 244 insertions, 152 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index 5fda6248c2..84a7432fdb 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -1,30 +1,40 @@ // Copyright (c) 2009-2010 Satoshi Nakamoto -// Copyright (c) 2009-2014 The Bitcoin developers +// Copyright (c) 2009-2014 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #include "interpreter.h" -#include "core/transaction.h" +#include "primitives/transaction.h" #include "crypto/ripemd160.h" #include "crypto/sha1.h" -#include "crypto/sha2.h" +#include "crypto/sha256.h" #include "eccryptoverify.h" #include "pubkey.h" #include "script/script.h" #include "uint256.h" -#include "util.h" using namespace std; typedef vector<unsigned char> valtype; -static const valtype vchFalse(0); -static const valtype vchZero(0); -static const valtype vchTrue(1, 1); -static const CScriptNum bnZero(0); -static const CScriptNum bnOne(1); -static const CScriptNum bnFalse(0); -static const CScriptNum bnTrue(1); + +namespace { + +inline bool set_success(ScriptError* ret) +{ + if (ret) + *ret = SCRIPT_ERR_OK; + return true; +} + +inline bool set_error(ScriptError* ret, const ScriptError serror) +{ + if (ret) + *ret = serror; + return false; +} + +} // anon namespace bool CastToBool(const valtype& vch) { @@ -50,21 +60,28 @@ bool CastToBool(const valtype& vch) static inline void popstack(vector<valtype>& stack) { if (stack.empty()) - throw runtime_error("popstack() : stack empty"); + throw runtime_error("popstack(): stack empty"); stack.pop_back(); } bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) { - if (vchPubKey.size() < 33) - return error("Non-canonical public key: too short"); + if (vchPubKey.size() < 33) { + // Non-canonical public key: too short + return false; + } if (vchPubKey[0] == 0x04) { - if (vchPubKey.size() != 65) - return error("Non-canonical public key: invalid length for uncompressed key"); + if (vchPubKey.size() != 65) { + // Non-canonical public key: invalid length for uncompressed key + return false; + } } else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) { - if (vchPubKey.size() != 33) - return error("Non-canonical public key: invalid length for compressed key"); + if (vchPubKey.size() != 33) { + // Non-canonical public key: invalid length for compressed key + return false; + } } else { - return error("Non-canonical public key: neither compressed nor uncompressed"); + // Non-canonical public key: neither compressed nor uncompressed + return false; } return true; } @@ -76,50 +93,77 @@ bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) { * in which case a single 0 byte is necessary and even required). * * See https://bitcointalk.org/index.php?topic=8392.msg127623#msg127623 + * + * This function is consensus-critical since BIP66. */ -bool static IsDERSignature(const valtype &vchSig) { - - if (vchSig.size() < 9) - return error("Non-canonical signature: too short"); - if (vchSig.size() > 73) - return error("Non-canonical signature: too long"); - if (vchSig[0] != 0x30) - return error("Non-canonical signature: wrong type"); - if (vchSig[1] != vchSig.size()-3) - return error("Non-canonical signature: wrong length marker"); - unsigned int nLenR = vchSig[3]; - if (5 + nLenR >= vchSig.size()) - return error("Non-canonical signature: S length misplaced"); - unsigned int nLenS = vchSig[5+nLenR]; - if ((unsigned long)(nLenR+nLenS+7) != vchSig.size()) - return error("Non-canonical signature: R+S length mismatch"); - - const unsigned char *R = &vchSig[4]; - if (R[-2] != 0x02) - return error("Non-canonical signature: R value type mismatch"); - if (nLenR == 0) - return error("Non-canonical signature: R length is zero"); - if (R[0] & 0x80) - return error("Non-canonical signature: R value negative"); - if (nLenR > 1 && (R[0] == 0x00) && !(R[1] & 0x80)) - return error("Non-canonical signature: R value excessively padded"); +bool static IsValidSignatureEncoding(const std::vector<unsigned char> &sig) { + // Format: 0x30 [total-length] 0x02 [R-length] [R] 0x02 [S-length] [S] [sighash] + // * total-length: 1-byte length descriptor of everything that follows, + // excluding the sighash byte. + // * R-length: 1-byte length descriptor of the R value that follows. + // * R: arbitrary-length big-endian encoded R value. It must use the shortest + // possible encoding for a positive integers (which means no null bytes at + // the start, except a single one when the next byte has its highest bit set). + // * S-length: 1-byte length descriptor of the S value that follows. + // * S: arbitrary-length big-endian encoded S value. The same rules apply. + // * sighash: 1-byte value indicating what data is hashed (not part of the DER + // signature) - const unsigned char *S = &vchSig[6+nLenR]; - if (S[-2] != 0x02) - return error("Non-canonical signature: S value type mismatch"); - if (nLenS == 0) - return error("Non-canonical signature: S length is zero"); - if (S[0] & 0x80) - return error("Non-canonical signature: S value negative"); - if (nLenS > 1 && (S[0] == 0x00) && !(S[1] & 0x80)) - return error("Non-canonical signature: S value excessively padded"); + // Minimum and maximum size constraints. + if (sig.size() < 9) return false; + if (sig.size() > 73) return false; + + // A signature is of type 0x30 (compound). + if (sig[0] != 0x30) return false; + + // Make sure the length covers the entire signature. + if (sig[1] != sig.size() - 3) return false; + + // Extract the length of the R element. + unsigned int lenR = sig[3]; + + // Make sure the length of the S element is still inside the signature. + if (5 + lenR >= sig.size()) return false; + + // Extract the length of the S element. + unsigned int lenS = sig[5 + lenR]; + + // Verify that the length of the signature matches the sum of the length + // of the elements. + if ((size_t)(lenR + lenS + 7) != sig.size()) return false; + + // Check whether the R element is an integer. + if (sig[2] != 0x02) return false; + + // Zero-length integers are not allowed for R. + if (lenR == 0) return false; + + // Negative numbers are not allowed for R. + if (sig[4] & 0x80) return false; + + // Null bytes at the start of R are not allowed, unless R would + // otherwise be interpreted as a negative number. + if (lenR > 1 && (sig[4] == 0x00) && !(sig[5] & 0x80)) return false; + + // Check whether the S element is an integer. + if (sig[lenR + 4] != 0x02) return false; + + // Zero-length integers are not allowed for S. + if (lenS == 0) return false; + + // Negative numbers are not allowed for S. + if (sig[lenR + 6] & 0x80) return false; + + // Null bytes at the start of S are not allowed, unless S would otherwise be + // interpreted as a negative number. + if (lenS > 1 && (sig[lenR + 6] == 0x00) && !(sig[lenR + 7] & 0x80)) return false; return true; } -bool static IsLowDERSignature(const valtype &vchSig) { - if (!IsDERSignature(vchSig)) { - return false; +bool static IsLowDERSignature(const valtype &vchSig, ScriptError* serror) { + if (!IsValidSignatureEncoding(vchSig)) { + return set_error(serror, SCRIPT_ERR_SIG_DER); } unsigned int nLenR = vchSig[3]; unsigned int nLenS = vchSig[5+nLenR]; @@ -128,7 +172,7 @@ bool static IsLowDERSignature(const valtype &vchSig) { // complement modulo the order could have been used instead, which is // one byte shorter when encoded correctly. if (!eccrypto::CheckSignatureElement(S, nLenS, true)) - return error("Non-canonical signature: S value is unnecessarily high"); + return set_error(serror, SCRIPT_ERR_SIG_HIGH_S); return true; } @@ -139,25 +183,31 @@ bool static IsDefinedHashtypeSignature(const valtype &vchSig) { } unsigned char nHashType = vchSig[vchSig.size() - 1] & (~(SIGHASH_ANYONECANPAY)); if (nHashType < SIGHASH_ALL || nHashType > SIGHASH_SINGLE) - return error("Non-canonical signature: unknown hashtype byte"); + return false; return true; } -bool static CheckSignatureEncoding(const valtype &vchSig, unsigned int flags) { - if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsDERSignature(vchSig)) { - return false; - } else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig)) { +bool static CheckSignatureEncoding(const valtype &vchSig, unsigned int flags, ScriptError* serror) { + // Empty signature. Not strictly DER encoded, but allowed to provide a + // compact way to provide an invalid signature for use with CHECK(MULTI)SIG + if (vchSig.size() == 0) { + return true; + } + if ((flags & (SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC)) != 0 && !IsValidSignatureEncoding(vchSig)) { + return set_error(serror, SCRIPT_ERR_SIG_DER); + } else if ((flags & SCRIPT_VERIFY_LOW_S) != 0 && !IsLowDERSignature(vchSig, serror)) { + // serror is set return false; } else if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsDefinedHashtypeSignature(vchSig)) { - return false; + return set_error(serror, SCRIPT_ERR_SIG_HASHTYPE); } return true; } -bool static CheckPubKeyEncoding(const valtype &vchSig, unsigned int flags) { +bool static CheckPubKeyEncoding(const valtype &vchSig, unsigned int flags, ScriptError* serror) { if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsCompressedOrUncompressedPubKey(vchSig)) { - return false; + return set_error(serror, SCRIPT_ERR_PUBKEYTYPE); } return true; } @@ -185,8 +235,16 @@ bool static CheckMinimalPush(const valtype& data, opcodetype opcode) { return true; } -bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker) +bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) { + static const CScriptNum bnZero(0); + static const CScriptNum bnOne(1); + static const CScriptNum bnFalse(0); + static const CScriptNum bnTrue(1); + static const valtype vchFalse(0); + static const valtype vchZero(0); + static const valtype vchTrue(1, 1); + CScript::const_iterator pc = script.begin(); CScript::const_iterator pend = script.end(); CScript::const_iterator pbegincodehash = script.begin(); @@ -194,8 +252,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un valtype vchPushValue; vector<bool> vfExec; vector<valtype> altstack; + set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); if (script.size() > 10000) - return false; + return set_error(serror, SCRIPT_ERR_SCRIPT_SIZE); int nOpCount = 0; bool fRequireMinimal = (flags & SCRIPT_VERIFY_MINIMALDATA) != 0; @@ -209,13 +268,13 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // Read instruction // if (!script.GetOp(pc, opcode, vchPushValue)) - return false; + return set_error(serror, SCRIPT_ERR_BAD_OPCODE); if (vchPushValue.size() > MAX_SCRIPT_ELEMENT_SIZE) - return false; + return set_error(serror, SCRIPT_ERR_PUSH_SIZE); // Note how OP_RESERVED does not count towards the opcode limit. if (opcode > OP_16 && ++nOpCount > 201) - return false; + return set_error(serror, SCRIPT_ERR_OP_COUNT); if (opcode == OP_CAT || opcode == OP_SUBSTR || @@ -232,11 +291,11 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un opcode == OP_MOD || opcode == OP_LSHIFT || opcode == OP_RSHIFT) - return false; // Disabled opcodes. + return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE); // Disabled opcodes. if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4) { if (fRequireMinimal && !CheckMinimalPush(vchPushValue, opcode)) { - return false; + return set_error(serror, SCRIPT_ERR_MINIMALDATA); } stack.push_back(vchPushValue); } else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF)) @@ -276,8 +335,14 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // Control // case OP_NOP: + break; + case OP_NOP1: case OP_NOP2: case OP_NOP3: case OP_NOP4: case OP_NOP5: case OP_NOP6: case OP_NOP7: case OP_NOP8: case OP_NOP9: case OP_NOP10: + { + if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) + return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS); + } break; case OP_IF: @@ -288,7 +353,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un if (fExec) { if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); valtype& vch = stacktop(-1); fValue = CastToBool(vch); if (opcode == OP_NOTIF) @@ -302,7 +367,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un case OP_ELSE: { if (vfExec.empty()) - return false; + return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); vfExec.back() = !vfExec.back(); } break; @@ -310,7 +375,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un case OP_ENDIF: { if (vfExec.empty()) - return false; + return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); vfExec.pop_back(); } break; @@ -320,18 +385,18 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // (true -- ) or // (false -- false) and return if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); bool fValue = CastToBool(stacktop(-1)); if (fValue) popstack(stack); else - return false; + return set_error(serror, SCRIPT_ERR_VERIFY); } break; case OP_RETURN: { - return false; + return set_error(serror, SCRIPT_ERR_OP_RETURN); } break; @@ -342,7 +407,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un case OP_TOALTSTACK: { if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); altstack.push_back(stacktop(-1)); popstack(stack); } @@ -351,7 +416,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un case OP_FROMALTSTACK: { if (altstack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_ALTSTACK_OPERATION); stack.push_back(altstacktop(-1)); popstack(altstack); } @@ -361,7 +426,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- ) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); popstack(stack); popstack(stack); } @@ -371,7 +436,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- x1 x2 x1 x2) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-2); valtype vch2 = stacktop(-1); stack.push_back(vch1); @@ -383,7 +448,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 x3 -- x1 x2 x3 x1 x2 x3) if (stack.size() < 3) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-3); valtype vch2 = stacktop(-2); valtype vch3 = stacktop(-1); @@ -397,7 +462,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2) if (stack.size() < 4) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-4); valtype vch2 = stacktop(-3); stack.push_back(vch1); @@ -409,7 +474,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 x3 x4 x5 x6 -- x3 x4 x5 x6 x1 x2) if (stack.size() < 6) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch1 = stacktop(-6); valtype vch2 = stacktop(-5); stack.erase(stack.end()-6, stack.end()-4); @@ -422,7 +487,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 x3 x4 -- x3 x4 x1 x2) if (stack.size() < 4) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-4), stacktop(-2)); swap(stacktop(-3), stacktop(-1)); } @@ -432,7 +497,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x - 0 | x x) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); if (CastToBool(vch)) stack.push_back(vch); @@ -451,7 +516,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x -- ) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); popstack(stack); } break; @@ -460,7 +525,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x -- x x) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); stack.push_back(vch); } @@ -470,7 +535,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- x2) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); stack.erase(stack.end() - 2); } break; @@ -479,7 +544,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- x1 x2 x1) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-2); stack.push_back(vch); } @@ -491,11 +556,11 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // (xn ... x2 x1 x0 n - xn ... x2 x1 x0 xn) // (xn ... x2 x1 x0 n - ... x2 x1 x0 xn) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int n = CScriptNum(stacktop(-1), fRequireMinimal).getint(); popstack(stack); if (n < 0 || n >= (int)stack.size()) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-n-1); if (opcode == OP_ROLL) stack.erase(stack.end()-n-1); @@ -509,7 +574,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // x2 x1 x3 after first swap // x2 x3 x1 after second swap if (stack.size() < 3) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-3), stacktop(-2)); swap(stacktop(-2), stacktop(-1)); } @@ -519,7 +584,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- x2 x1) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); swap(stacktop(-2), stacktop(-1)); } break; @@ -528,7 +593,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- x2 x1 x2) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype vch = stacktop(-1); stack.insert(stack.end()-2, vch); } @@ -539,7 +604,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (in -- in size) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn(stacktop(-1).size()); stack.push_back(bn.getvch()); } @@ -555,7 +620,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 - bool) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vch1 = stacktop(-2); valtype& vch2 = stacktop(-1); bool fEqual = (vch1 == vch2); @@ -572,7 +637,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un if (fEqual) popstack(stack); else - return false; + return set_error(serror, SCRIPT_ERR_EQUALVERIFY); } } break; @@ -590,7 +655,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (in -- out) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn(stacktop(-1), fRequireMinimal); switch (opcode) { @@ -623,7 +688,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x1 x2 -- out) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn1(stacktop(-2), fRequireMinimal); CScriptNum bn2(stacktop(-1), fRequireMinimal); CScriptNum bn(0); @@ -659,7 +724,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un if (CastToBool(stacktop(-1))) popstack(stack); else - return false; + return set_error(serror, SCRIPT_ERR_NUMEQUALVERIFY); } } break; @@ -668,7 +733,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (x min max -- out) if (stack.size() < 3) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); CScriptNum bn1(stacktop(-3), fRequireMinimal); CScriptNum bn2(stacktop(-2), fRequireMinimal); CScriptNum bn3(stacktop(-1), fRequireMinimal); @@ -692,7 +757,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (in -- hash) if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vch = stacktop(-1); valtype vchHash((opcode == OP_RIPEMD160 || opcode == OP_SHA1 || opcode == OP_HASH160) ? 20 : 32); if (opcode == OP_RIPEMD160) @@ -722,7 +787,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un { // (sig pubkey -- bool) if (stack.size() < 2) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); valtype& vchSig = stacktop(-2); valtype& vchPubKey = stacktop(-1); @@ -733,11 +798,11 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // Drop the signature, since there's no way for a signature to sign itself scriptCode.FindAndDelete(CScript(vchSig)); - if (!CheckSignatureEncoding(vchSig, flags)) { + if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, serror)) { + //serror is set return false; } - - bool fSuccess = CheckPubKeyEncoding(vchPubKey, flags) && checker.CheckSig(vchSig, vchPubKey, scriptCode); + bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode); popstack(stack); popstack(stack); @@ -747,7 +812,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un if (fSuccess) popstack(stack); else - return false; + return set_error(serror, SCRIPT_ERR_CHECKSIGVERIFY); } } break; @@ -759,26 +824,26 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un int i = 1; if ((int)stack.size() < i) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int nKeysCount = CScriptNum(stacktop(-i), fRequireMinimal).getint(); if (nKeysCount < 0 || nKeysCount > 20) - return false; + return set_error(serror, SCRIPT_ERR_PUBKEY_COUNT); nOpCount += nKeysCount; if (nOpCount > 201) - return false; + return set_error(serror, SCRIPT_ERR_OP_COUNT); int ikey = ++i; i += nKeysCount; if ((int)stack.size() < i) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); int nSigsCount = CScriptNum(stacktop(-i), fRequireMinimal).getint(); if (nSigsCount < 0 || nSigsCount > nKeysCount) - return false; + return set_error(serror, SCRIPT_ERR_SIG_COUNT); int isig = ++i; i += nSigsCount; if ((int)stack.size() < i) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); // Subset of script starting at the most recent codeseparator CScript scriptCode(pbegincodehash, pend); @@ -796,12 +861,16 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un valtype& vchSig = stacktop(-isig); valtype& vchPubKey = stacktop(-ikey); - if (!CheckSignatureEncoding(vchSig, flags)) { + // Note how this makes the exact order of pubkey/signature evaluation + // distinguishable by CHECKMULTISIG NOT if the STRICTENC flag is set. + // See the script_(in)valid tests for details. + if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, serror)) { + // serror is set return false; } // Check signature - bool fOk = CheckPubKeyEncoding(vchPubKey, flags) && checker.CheckSig(vchSig, vchPubKey, scriptCode); + bool fOk = checker.CheckSig(vchSig, vchPubKey, scriptCode); if (fOk) { isig++; @@ -811,7 +880,8 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un nKeysCount--; // If there are more signatures left than keys left, - // then too many signatures have failed + // then too many signatures have failed. Exit early, + // without checking any further signatures. if (nSigsCount > nKeysCount) fSuccess = false; } @@ -827,9 +897,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un // so optionally verify it is exactly equal to zero prior // to removing it from the stack. if (stack.size() < 1) - return false; + return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION); if ((flags & SCRIPT_VERIFY_NULLDUMMY) && stacktop(-1).size()) - return error("CHECKMULTISIG dummy argument not null"); + return set_error(serror, SCRIPT_ERR_SIG_NULLDUMMY); popstack(stack); stack.push_back(fSuccess ? vchTrue : vchFalse); @@ -839,29 +909,29 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un if (fSuccess) popstack(stack); else - return false; + return set_error(serror, SCRIPT_ERR_CHECKMULTISIGVERIFY); } } break; default: - return false; + return set_error(serror, SCRIPT_ERR_BAD_OPCODE); } // Size limits if (stack.size() + altstack.size() > 1000) - return false; + return set_error(serror, SCRIPT_ERR_STACK_SIZE); } } catch (...) { - return false; + return set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); } if (!vfExec.empty()) - return false; + return set_error(serror, SCRIPT_ERR_UNBALANCED_CONDITIONAL); - return true; + return set_success(serror); } namespace { @@ -965,16 +1035,17 @@ public: uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType) { + static const uint256 one(uint256S("0000000000000000000000000000000000000000000000000000000000000001")); if (nIn >= txTo.vin.size()) { - LogPrintf("ERROR: SignatureHash() : nIn=%d out of range\n", nIn); - return 1; + // nIn out of range + return one; } // Check for invalid use of SIGHASH_SINGLE if ((nHashType & 0x1f) == SIGHASH_SINGLE) { if (nIn >= txTo.vout.size()) { - LogPrintf("ERROR: SignatureHash() : nOut=%d out of range\n", nIn); - return 1; + // nOut out of range + return one; } } @@ -987,12 +1058,12 @@ uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsig return ss.GetHash(); } -bool SignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const +bool TransactionSignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const { return pubkey.Verify(sighash, vchSig); } -bool SignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vector<unsigned char>& vchPubKey, const CScript& scriptCode) const +bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vector<unsigned char>& vchPubKey, const CScript& scriptCode) const { CPubKey pubkey(vchPubKey); if (!pubkey.IsValid()) @@ -1005,7 +1076,7 @@ bool SignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vec int nHashType = vchSig.back(); vchSig.pop_back(); - uint256 sighash = SignatureHash(scriptCode, txTo, nIn, nHashType); + uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType); if (!VerifySignature(vchSig, pubkey, sighash)) return false; @@ -1013,46 +1084,67 @@ bool SignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vec return true; } -bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker) +bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror) { + set_error(serror, SCRIPT_ERR_UNKNOWN_ERROR); + if ((flags & SCRIPT_VERIFY_SIGPUSHONLY) != 0 && !scriptSig.IsPushOnly()) { - return false; + return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY); } vector<vector<unsigned char> > stack, stackCopy; - if (!EvalScript(stack, scriptSig, flags, checker)) + if (!EvalScript(stack, scriptSig, flags, checker, serror)) + // serror is set return false; if (flags & SCRIPT_VERIFY_P2SH) stackCopy = stack; - if (!EvalScript(stack, scriptPubKey, flags, checker)) + if (!EvalScript(stack, scriptPubKey, flags, checker, serror)) + // serror is set return false; if (stack.empty()) - return false; - + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); if (CastToBool(stack.back()) == false) - return false; + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); // Additional validation for spend-to-script-hash transactions: if ((flags & SCRIPT_VERIFY_P2SH) && scriptPubKey.IsPayToScriptHash()) { - if (!scriptSig.IsPushOnly()) // scriptSig must be literals-only - return false; // or validation fails + // scriptSig must be literals-only or validation fails + if (!scriptSig.IsPushOnly()) + return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY); - // stackCopy cannot be empty here, because if it was the + // Restore stack. + swap(stack, stackCopy); + + // stack cannot be empty here, because if it was the // P2SH HASH <> EQUAL scriptPubKey would be evaluated with // an empty stack and the EvalScript above would return false. - assert(!stackCopy.empty()); + assert(!stack.empty()); - const valtype& pubKeySerialized = stackCopy.back(); + const valtype& pubKeySerialized = stack.back(); CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end()); - popstack(stackCopy); + popstack(stack); - if (!EvalScript(stackCopy, pubKey2, flags, checker)) - return false; - if (stackCopy.empty()) + if (!EvalScript(stack, pubKey2, flags, checker, serror)) + // serror is set return false; - return CastToBool(stackCopy.back()); + if (stack.empty()) + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); + if (!CastToBool(stack.back())) + return set_error(serror, SCRIPT_ERR_EVAL_FALSE); } - return true; + // The CLEANSTACK check is only performed after potential P2SH evaluation, + // as the non-P2SH evaluation of a P2SH script will obviously not result in + // a clean stack (the P2SH inputs remain). + if ((flags & SCRIPT_VERIFY_CLEANSTACK) != 0) { + // Disallow CLEANSTACK without P2SH, as otherwise a switch CLEANSTACK->P2SH+CLEANSTACK + // would be possible, which is not a softfork (and P2SH should be one). + assert((flags & SCRIPT_VERIFY_P2SH) != 0); + if (stack.size() != 1) { + return set_error(serror, SCRIPT_ERR_CLEANSTACK); + } + } + + return set_success(serror); } |