diff options
Diffstat (limited to 'src/script.cpp')
| -rw-r--r-- | src/script.cpp | 220 |
1 files changed, 204 insertions, 16 deletions
diff --git a/src/script.cpp b/src/script.cpp index e8dd93d081..36d208c247 100644 --- a/src/script.cpp +++ b/src/script.cpp @@ -253,7 +253,68 @@ const char* GetOpName(opcodetype opcode) } } -bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, int nHashType) +bool IsCanonicalPubKey(const valtype &vchPubKey) { + if (vchPubKey.size() < 33) + return error("Non-canonical public key: too short"); + if (vchPubKey[0] == 0x04) { + if (vchPubKey.size() != 65) + return error("Non-canonical public key: invalid length for uncompressed key"); + } else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) { + if (vchPubKey.size() != 33) + return error("Non-canonical public key: invalid length for compressed key"); + } else { + return error("Non-canonical public key: compressed nor uncompressed"); + } + return true; +} + +bool IsCanonicalSignature(const valtype &vchSig) { + // See https://bitcointalk.org/index.php?topic=8392.msg127623#msg127623 + // A canonical signature exists of: <30> <total len> <02> <len R> <R> <02> <len S> <S> <hashtype> + // Where R and S are not negative (their first byte has its highest bit not set), and not + // excessively padded (do not start with a 0 byte, unless an otherwise negative number follows, + // in which case a single 0 byte is necessary and even required). + if (vchSig.size() < 9) + return error("Non-canonical signature: too short"); + if (vchSig.size() > 73) + return error("Non-canonical signature: too long"); + if (vchSig[vchSig.size() - 1] & 0x7C) + return error("Non-canonical signature: unknown hashtype byte"); + 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"); + + 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"); + + return true; +} + +bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, const CTransaction& txTo, unsigned int nIn, bool fStrictEncodings, int nHashType) { CAutoBN_CTX pctx; CScript::const_iterator pc = script.begin(); @@ -944,7 +1005,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co // Drop the signature, since there's no way for a signature to sign itself scriptCode.FindAndDelete(CScript(vchSig)); - bool fSuccess = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType); + bool fSuccess = (!fStrictEncodings || (IsCanonicalSignature(vchSig) && IsCanonicalPubKey(vchPubKey))); + if (fSuccess) + fSuccess = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType); popstack(stack); popstack(stack); @@ -1004,8 +1067,11 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, co valtype& vchPubKey = stacktop(-ikey); // Check signature - if (CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType)) - { + bool fOk = (!fStrictEncodings || (IsCanonicalSignature(vchSig) && IsCanonicalPubKey(vchPubKey))); + if (fOk) + fOk = CheckSig(vchSig, vchPubKey, scriptCode, txTo, nIn, nHashType); + + if (fOk) { isig++; nSigsCount--; } @@ -1571,14 +1637,14 @@ bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, vecto } bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CTransaction& txTo, unsigned int nIn, - bool fValidatePayToScriptHash, int nHashType) + bool fValidatePayToScriptHash, bool fStrictEncodings, int nHashType) { vector<vector<unsigned char> > stack, stackCopy; - if (!EvalScript(stack, scriptSig, txTo, nIn, nHashType)) + if (!EvalScript(stack, scriptSig, txTo, nIn, fStrictEncodings, nHashType)) return false; if (fValidatePayToScriptHash) stackCopy = stack; - if (!EvalScript(stack, scriptPubKey, txTo, nIn, nHashType)) + if (!EvalScript(stack, scriptPubKey, txTo, nIn, fStrictEncodings, nHashType)) return false; if (stack.empty()) return false; @@ -1596,7 +1662,7 @@ bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const C CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end()); popstack(stackCopy); - if (!EvalScript(stackCopy, pubKey2, txTo, nIn, nHashType)) + if (!EvalScript(stackCopy, pubKey2, txTo, nIn, fStrictEncodings, nHashType)) return false; if (stackCopy.empty()) return false; @@ -1639,7 +1705,7 @@ bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CTransa } // Test solution - return VerifyScript(txin.scriptSig, fromPubKey, txTo, nIn, true, 0); + return VerifyScript(txin.scriptSig, fromPubKey, txTo, nIn, true, true, 0); } bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CTransaction& txTo, unsigned int nIn, int nHashType) @@ -1652,7 +1718,7 @@ bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CTrans return SignSignature(keystore, txout.scriptPubKey, txTo, nIn, nHashType); } -bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsigned int nIn, bool fValidatePayToScriptHash, int nHashType) +bool VerifySignature(const CCoins& txFrom, const CTransaction& txTo, unsigned int nIn, bool fValidatePayToScriptHash, bool fStrictEncodings, int nHashType) { assert(nIn < txTo.vin.size()); const CTxIn& txin = txTo.vin[nIn]; @@ -1660,10 +1726,7 @@ bool VerifySignature(const CTransaction& txFrom, const CTransaction& txTo, unsig return false; const CTxOut& txout = txFrom.vout[txin.prevout.n]; - if (txin.prevout.hash != txFrom.GetHash()) - return false; - - return VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, fValidatePayToScriptHash, nHashType); + return VerifyScript(txin.scriptSig, txout.scriptPubKey, txTo, nIn, fValidatePayToScriptHash, fStrictEncodings, nHashType); } static CScript PushAll(const vector<valtype>& values) @@ -1781,9 +1844,9 @@ CScript CombineSignatures(CScript scriptPubKey, const CTransaction& txTo, unsign Solver(scriptPubKey, txType, vSolutions); vector<valtype> stack1; - EvalScript(stack1, scriptSig1, CTransaction(), 0, 0); + EvalScript(stack1, scriptSig1, CTransaction(), 0, true, 0); vector<valtype> stack2; - EvalScript(stack2, scriptSig2, CTransaction(), 0, 0); + EvalScript(stack2, scriptSig2, CTransaction(), 0, true, 0); return CombineSignatures(scriptPubKey, txTo, nIn, txType, vSolutions, stack1, stack2); } @@ -1884,3 +1947,128 @@ void CScript::SetMultisig(int nRequired, const std::vector<CKey>& keys) *this << key.GetPubKey(); *this << EncodeOP_N(keys.size()) << OP_CHECKMULTISIG; } + +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(std::vector<unsigned char> &pubkey) const +{ + if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG + && (script[1] == 0x02 || script[1] == 0x03)) { + pubkey.resize(33); + memcpy(&pubkey[0], &script[1], 33); + return true; + } + if (script.size() == 67 && script[0] == 65 && script[66] == OP_CHECKSIG + && script[1] == 0x04) { + pubkey.resize(65); + memcpy(&pubkey[0], &script[1], 65); + CKey key; + return (key.SetPubKey(CPubKey(pubkey))); // SetPubKey fails if this is not a valid public key, 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; + } + std::vector<unsigned char> 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: + std::vector<unsigned char> vch(33, 0x00); + vch[0] = nSize - 2; + memcpy(&vch[1], &in[0], 32); + CKey key; + if (!key.SetPubKey(CPubKey(vch))) + return false; + key.SetCompressedPubKey(false); // Decompress public key + CPubKey pubkey = key.GetPubKey(); + script.resize(67); + script[0] = 65; + memcpy(&script[1], &pubkey.Raw()[0], 65); + script[66] = OP_CHECKSIG; + return true; + } + return false; +} |