[consensus] MOVEONLY: Move single-sig checking EvalScript code to EvalChecksig

This is in preparation for adding different signature verification rules,
specifically tapscript (BIP 342), which interprets opcode 0xac and 0xad
as Schnorr signature verifications.
This commit is contained in:
Pieter Wuille
2019-10-18 15:23:42 -07:00
committed by John Newbery
parent ac579ada7e
commit 14e8cf974a

View File

@@ -342,6 +342,35 @@ public:
};
}
/** Helper for OP_CHECKSIG and OP_CHECKSIGVERIFY
*
* A return value of false means the script fails entirely. When true is returned, the
* fSuccess variable indicates whether the signature check itself succeeded.
*/
static bool EvalChecksig(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
{
// Subset of script starting at the most recent codeseparator
CScript scriptCode(pbegincodehash, pend);
// Drop the signature in pre-segwit scripts but not segwit scripts
if (sigversion == SigVersion::BASE) {
int found = FindAndDelete(scriptCode, CScript() << vchSig);
if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
}
if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
//serror is set
return false;
}
fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
return true;
}
bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
{
static const CScriptNum bnZero(0);
@@ -985,25 +1014,8 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
valtype& vchSig = stacktop(-2);
valtype& vchPubKey = stacktop(-1);
// Subset of script starting at the most recent codeseparator
CScript scriptCode(pbegincodehash, pend);
// Drop the signature in pre-segwit scripts but not segwit scripts
if (sigversion == SigVersion::BASE) {
int found = FindAndDelete(scriptCode, CScript() << vchSig);
if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
}
if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
//serror is set
return false;
}
bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
bool fSuccess = true;
if (!EvalChecksig(vchSig, vchPubKey, pbegincodehash, pend, flags, checker, sigversion, serror, fSuccess)) return false;
popstack(stack);
popstack(stack);
stack.push_back(fSuccess ? vchTrue : vchFalse);