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Merge #12714: Introduce interface for signing providers

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d40f06a Introduce interface for signing providers (Pieter Wuille)

Pull request description:

  `CKeyStore` is a rich interface that provides many features, including knowledge of scripts and pubkeys for solving, private keys for signing, in addition to watch-only keys and scripts, and distinguishing lack of keys from them just being encrypted.

  The signing logic in script/sign does not actually need most of these features. Here we introduce a simpler interface (`SigningProvider`) which *only* provides keys and scripts. This is actually sufficient for signing.

  In addtion, we swap the dependency between keystore and script/sign (keystore now depends on script/script with `CKeyStore` deriving from `SigningProvider`, rather than `CKeyStore` being the interface that signing relies on).

  This is a very early step towards the design in https://gist.github.com/sipa/125cfa1615946d0c3f3eec2ad7f250a2, separating the concern between deciding what outputs are ours and signing.

Tree-SHA512: d511b7b03eec0e513530db1d9ae5aacf6d0bfa1d3e1c03d06c5bde396bafb5824c4491b227d32bcda9288530caf49835da18e846ccf66538d6c0cc6ae27291c9
This commit is contained in:
Wladimir J. van der Laan 2018-03-27 20:16:45 +02:00
commit bf8fc7d352
No known key found for this signature in database
GPG key ID: 1E4AED62986CD25D
3 changed files with 35 additions and 29 deletions
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8
src/keystore.h
View file

@ -9,35 +9,31 @@
#include <key.h>
#include <pubkey.h>
#include <script/script.h>
#include <script/sign.h>
#include <script/standard.h>
#include <sync.h>
#include <boost/signals2/signal.hpp>
/** A virtual base class for key stores */
class CKeyStore
class CKeyStore : public SigningProvider
{
protected:
mutable CCriticalSection cs_KeyStore;
public:
virtual ~CKeyStore() {}
//! Add a key to the store.
virtual bool AddKeyPubKey(const CKey &key, const CPubKey &pubkey) =0;
virtual bool AddKey(const CKey &key);
//! Check whether a key corresponding to a given address is present in the store.
virtual bool HaveKey(const CKeyID &address) const =0;
virtual bool GetKey(const CKeyID &address, CKey& keyOut) const =0;
virtual std::set<CKeyID> GetKeys() const =0;
virtual bool GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const =0;
//! Support for BIP 0013 : see https://github.com/bitcoin/bips/blob/master/bip-0013.mediawiki
virtual bool AddCScript(const CScript& redeemScript) =0;
virtual bool HaveCScript(const CScriptID &hash) const =0;
virtual std::set<CScriptID> GetCScripts() const =0;
virtual bool GetCScript(const CScriptID &hash, CScript& redeemScriptOut) const =0;
//! Support for Watch-only addresses
virtual bool AddWatchOnly(const CScript &dest) =0;

23
src/script/sign.cpp
View file

@ -6,7 +6,6 @@
#include <script/sign.h>
#include <key.h>
#include <keystore.h>
#include <policy/policy.h>
#include <primitives/transaction.h>
#include <script/standard.h>
@ -15,12 +14,12 @@
typedef std::vector<unsigned char> valtype;
TransactionSignatureCreator::TransactionSignatureCreator(const CKeyStore* keystoreIn, const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn) : BaseSignatureCreator(keystoreIn), txTo(txToIn), nIn(nInIn), nHashType(nHashTypeIn), amount(amountIn), checker(txTo, nIn, amountIn) {}
TransactionSignatureCreator::TransactionSignatureCreator(const SigningProvider* provider, const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn) : BaseSignatureCreator(provider), txTo(txToIn), nIn(nInIn), nHashType(nHashTypeIn), amount(amountIn), checker(txTo, nIn, amountIn) {}
bool TransactionSignatureCreator::CreateSig(std::vector<unsigned char>& vchSig, const CKeyID& address, const CScript& scriptCode, SigVersion sigversion) const
{
CKey key;
if (!keystore->GetKey(address, key))
if (!m_provider->GetKey(address, key))
return false;
// Signing with uncompressed keys is disabled in witness scripts
@ -91,12 +90,12 @@ static bool SignStep(const BaseSignatureCreator& creator, const CScript& scriptP
else
{
CPubKey vch;
creator.KeyStore().GetPubKey(keyID, vch);
creator.Provider().GetPubKey(keyID, vch);
ret.push_back(ToByteVector(vch));
}
return true;
case TX_SCRIPTHASH:
if (creator.KeyStore().GetCScript(uint160(vSolutions[0]), scriptRet)) {
if (creator.Provider().GetCScript(uint160(vSolutions[0]), scriptRet)) {
ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
return true;
}
@ -112,7 +111,7 @@ static bool SignStep(const BaseSignatureCreator& creator, const CScript& scriptP
case TX_WITNESS_V0_SCRIPTHASH:
CRIPEMD160().Write(&vSolutions[0][0], vSolutions[0].size()).Finalize(h160.begin());
if (creator.KeyStore().GetCScript(h160, scriptRet)) {
if (creator.Provider().GetCScript(h160, scriptRet)) {
ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
return true;
}
@ -206,12 +205,12 @@ void UpdateTransaction(CMutableTransaction& tx, unsigned int nIn, const Signatur
UpdateInput(tx.vin[nIn], data);
}
bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType)
bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType)
{
assert(nIn < txTo.vin.size());
CTransaction txToConst(txTo);
TransactionSignatureCreator creator(&keystore, &txToConst, nIn, amount, nHashType);
TransactionSignatureCreator creator(&provider, &txToConst, nIn, amount, nHashType);
SignatureData sigdata;
bool ret = ProduceSignature(creator, fromPubKey, sigdata);
@ -219,14 +218,14 @@ bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CMutabl
return ret;
}
bool SignSignature(const CKeyStore &keystore, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType)
{
assert(nIn < txTo.vin.size());
CTxIn& txin = txTo.vin[nIn];
assert(txin.prevout.n < txFrom.vout.size());
const CTxOut& txout = txFrom.vout[txin.prevout.n];
return SignSignature(keystore, txout.scriptPubKey, txTo, nIn, txout.nValue, nHashType);
return SignSignature(provider, txout.scriptPubKey, txTo, nIn, txout.nValue, nHashType);
}
static std::vector<valtype> CombineMultisig(const CScript& scriptPubKey, const BaseSignatureChecker& checker,
@ -427,13 +426,13 @@ bool DummySignatureCreator::CreateSig(std::vector<unsigned char>& vchSig, const
return true;
}
bool IsSolvable(const CKeyStore& store, const CScript& script)
bool IsSolvable(const SigningProvider& provider, const CScript& script)
{
// This check is to make sure that the script we created can actually be solved for and signed by us
// if we were to have the private keys. This is just to make sure that the script is valid and that,
// if found in a transaction, we would still accept and relay that transaction. In particular,
// it will reject witness outputs that require signing with an uncompressed public key.
DummySignatureCreator creator(&store);
DummySignatureCreator creator(&provider);
SignatureData sigs;
// Make sure that STANDARD_SCRIPT_VERIFY_FLAGS includes SCRIPT_VERIFY_WITNESS_PUBKEYTYPE, the most
// important property this function is designed to test for.

33
src/script/sign.h
View file

@ -8,21 +8,32 @@
#include <script/interpreter.h>
class CKey;
class CKeyID;
class CKeyStore;
class CScript;
class CScriptID;
class CTransaction;
struct CMutableTransaction;
/** An interface to be implemented by keystores that support signing. */
class SigningProvider
{
public:
virtual ~SigningProvider() {}
virtual bool GetCScript(const CScriptID &scriptid, CScript& script) const =0;
virtual bool GetPubKey(const CKeyID &address, CPubKey& pubkey) const =0;
virtual bool GetKey(const CKeyID &address, CKey& key) const =0;
};
/** Virtual base class for signature creators. */
class BaseSignatureCreator {
protected:
const CKeyStore* keystore;
const SigningProvider* m_provider;
public:
explicit BaseSignatureCreator(const CKeyStore* keystoreIn) : keystore(keystoreIn) {}
const CKeyStore& KeyStore() const { return *keystore; };
explicit BaseSignatureCreator(const SigningProvider* provider) : m_provider(provider) {}
const SigningProvider& Provider() const { return *m_provider; }
virtual ~BaseSignatureCreator() {}
virtual const BaseSignatureChecker& Checker() const =0;
@ -39,7 +50,7 @@ class TransactionSignatureCreator : public BaseSignatureCreator {
const TransactionSignatureChecker checker;
public:
TransactionSignatureCreator(const CKeyStore* keystoreIn, const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn=SIGHASH_ALL);
TransactionSignatureCreator(const SigningProvider* provider, const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn=SIGHASH_ALL);
const BaseSignatureChecker& Checker() const override { return checker; }
bool CreateSig(std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
};
@ -48,13 +59,13 @@ class MutableTransactionSignatureCreator : public TransactionSignatureCreator {
CTransaction tx;
public:
MutableTransactionSignatureCreator(const CKeyStore* keystoreIn, const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn) : TransactionSignatureCreator(keystoreIn, &tx, nInIn, amountIn, nHashTypeIn), tx(*txToIn) {}
MutableTransactionSignatureCreator(const SigningProvider* provider, const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn) : TransactionSignatureCreator(provider, &tx, nInIn, amountIn, nHashTypeIn), tx(*txToIn) {}
};
/** A signature creator that just produces 72-byte empty signatures. */
class DummySignatureCreator : public BaseSignatureCreator {
public:
explicit DummySignatureCreator(const CKeyStore* keystoreIn) : BaseSignatureCreator(keystoreIn) {}
explicit DummySignatureCreator(const SigningProvider* provider) : BaseSignatureCreator(provider) {}
const BaseSignatureChecker& Checker() const override;
bool CreateSig(std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
};
@ -71,8 +82,8 @@ struct SignatureData {
bool ProduceSignature(const BaseSignatureCreator& creator, const CScript& scriptPubKey, SignatureData& sigdata);
/** Produce a script signature for a transaction. */
bool SignSignature(const CKeyStore &keystore, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType);
bool SignSignature(const CKeyStore& keystore, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType);
bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType);
bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType);
/** Combine two script signatures using a generic signature checker, intelligently, possibly with OP_0 placeholders. */
SignatureData CombineSignatures(const CScript& scriptPubKey, const BaseSignatureChecker& checker, const SignatureData& scriptSig1, const SignatureData& scriptSig2);
@ -84,8 +95,8 @@ void UpdateInput(CTxIn& input, const SignatureData& data);
/* Check whether we know how to sign for an output like this, assuming we
* have all private keys. While this function does not need private keys, the passed
* keystore is used to look up public keys and redeemscripts by hash.
* provider is used to look up public keys and redeemscripts by hash.
* Solvability is unrelated to whether we consider this output to be ours. */
bool IsSolvable(const CKeyStore& store, const CScript& script);
bool IsSolvable(const SigningProvider& provider, const CScript& script);
#endif // BITCOIN_SCRIPT_SIGN_H