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-rw-r--r--src/bench/verify_script.cpp2
-rw-r--r--src/key.cpp24
-rw-r--r--src/key.h2
-rw-r--r--src/script/sign.cpp22
-rw-r--r--src/script/sign.h4
-rw-r--r--src/test/key_tests.cpp36
-rw-r--r--src/test/script_tests.cpp2
-rw-r--r--src/wallet/wallet.cpp33
-rw-r--r--src/wallet/wallet.h29
9 files changed, 109 insertions, 45 deletions
diff --git a/src/bench/verify_script.cpp b/src/bench/verify_script.cpp
index 3421d56ed2..312b66e38a 100644
--- a/src/bench/verify_script.cpp
+++ b/src/bench/verify_script.cpp
@@ -76,7 +76,7 @@ static void VerifyScriptBench(benchmark::State& state)
CMutableTransaction txSpend = BuildSpendingTransaction(scriptSig, txCredit);
CScriptWitness& witness = txSpend.vin[0].scriptWitness;
witness.stack.emplace_back();
- key.Sign(SignatureHash(witScriptPubkey, txSpend, 0, SIGHASH_ALL, txCredit.vout[0].nValue, SigVersion::WITNESS_V0), witness.stack.back(), 0);
+ key.Sign(SignatureHash(witScriptPubkey, txSpend, 0, SIGHASH_ALL, txCredit.vout[0].nValue, SigVersion::WITNESS_V0), witness.stack.back());
witness.stack.back().push_back(static_cast<unsigned char>(SIGHASH_ALL));
witness.stack.push_back(ToByteVector(pubkey));
diff --git a/src/key.cpp b/src/key.cpp
index 22fc7047ce..df452cd330 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -189,7 +189,20 @@ CPubKey CKey::GetPubKey() const {
return result;
}
-bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
+// Check that the sig has a low R value and will be less than 71 bytes
+bool SigHasLowR(const secp256k1_ecdsa_signature* sig)
+{
+ unsigned char compact_sig[64];
+ secp256k1_ecdsa_signature_serialize_compact(secp256k1_context_sign, compact_sig, sig);
+
+ // In DER serialization, all values are interpreted as big-endian, signed integers. The highest bit in the integer indicates
+ // its signed-ness; 0 is positive, 1 is negative. When the value is interpreted as a negative integer, it must be converted
+ // to a positive value by prepending a 0x00 byte so that the highest bit is 0. We can avoid this prepending by ensuring that
+ // our highest bit is always 0, and thus we must check that the first byte is less than 0x80.
+ return compact_sig[0] < 0x80;
+}
+
+bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, bool grind, uint32_t test_case) const {
if (!fValid)
return false;
vchSig.resize(CPubKey::SIGNATURE_SIZE);
@@ -197,7 +210,14 @@ bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_
unsigned char extra_entropy[32] = {0};
WriteLE32(extra_entropy, test_case);
secp256k1_ecdsa_signature sig;
- int ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, test_case ? extra_entropy : nullptr);
+ uint32_t counter = 0;
+ int ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, (!grind && test_case) ? extra_entropy : nullptr);
+
+ // Grind for low R
+ while (ret && !SigHasLowR(&sig) && grind) {
+ WriteLE32(extra_entropy, ++counter);
+ ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, extra_entropy);
+ }
assert(ret);
secp256k1_ecdsa_signature_serialize_der(secp256k1_context_sign, vchSig.data(), &nSigLen, &sig);
vchSig.resize(nSigLen);
diff --git a/src/key.h b/src/key.h
index d437f4d53e..a3baa421e6 100644
--- a/src/key.h
+++ b/src/key.h
@@ -114,7 +114,7 @@ public:
* Create a DER-serialized signature.
* The test_case parameter tweaks the deterministic nonce.
*/
- bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig, uint32_t test_case = 0) const;
+ bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig, bool grind = true, uint32_t test_case = 0) const;
/**
* Create a compact signature (65 bytes), which allows reconstructing the used public key.
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index 65b5bf7aeb..1e4102c20f 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -417,22 +417,25 @@ public:
const DummySignatureChecker DUMMY_CHECKER;
class DummySignatureCreator final : public BaseSignatureCreator {
+private:
+ char m_r_len = 32;
+ char m_s_len = 32;
public:
- DummySignatureCreator() {}
+ DummySignatureCreator(char r_len, char s_len) : m_r_len(r_len), m_s_len(s_len) {}
const BaseSignatureChecker& Checker() const override { return DUMMY_CHECKER; }
bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override
{
// Create a dummy signature that is a valid DER-encoding
- vchSig.assign(72, '\000');
+ vchSig.assign(m_r_len + m_s_len + 7, '\000');
vchSig[0] = 0x30;
- vchSig[1] = 69;
+ vchSig[1] = m_r_len + m_s_len + 4;
vchSig[2] = 0x02;
- vchSig[3] = 33;
+ vchSig[3] = m_r_len;
vchSig[4] = 0x01;
- vchSig[4 + 33] = 0x02;
- vchSig[5 + 33] = 32;
- vchSig[6 + 33] = 0x01;
- vchSig[6 + 33 + 32] = SIGHASH_ALL;
+ vchSig[4 + m_r_len] = 0x02;
+ vchSig[5 + m_r_len] = m_s_len;
+ vchSig[6 + m_r_len] = 0x01;
+ vchSig[6 + m_r_len + m_s_len] = SIGHASH_ALL;
return true;
}
};
@@ -450,7 +453,8 @@ bool LookupHelper(const M& map, const K& key, V& value)
}
-const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR = DummySignatureCreator();
+const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR = DummySignatureCreator(32, 32);
+const BaseSignatureCreator& DUMMY_MAXIMUM_SIGNATURE_CREATOR = DummySignatureCreator(33, 32);
const SigningProvider& DUMMY_SIGNING_PROVIDER = SigningProvider();
bool IsSolvable(const SigningProvider& provider, const CScript& script)
diff --git a/src/script/sign.h b/src/script/sign.h
index 461aedc6da..24cddda51b 100644
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -80,8 +80,10 @@ public:
bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
};
-/** A signature creator that just produces 72-byte empty signatures. */
+/** A signature creator that just produces 71-byte empty signatures. */
extern const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR;
+/** A signature creator that just produces 72-byte empty signatures. */
+extern const BaseSignatureCreator& DUMMY_MAXIMUM_SIGNATURE_CREATOR;
typedef std::pair<CPubKey, std::vector<unsigned char>> SigPair;
diff --git a/src/test/key_tests.cpp b/src/test/key_tests.cpp
index d9c3525b19..61db70decb 100644
--- a/src/test/key_tests.cpp
+++ b/src/test/key_tests.cpp
@@ -152,4 +152,40 @@ BOOST_AUTO_TEST_CASE(key_test1)
BOOST_CHECK(detsigc == ParseHex("2052d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd561d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
}
+BOOST_AUTO_TEST_CASE(key_signature_tests)
+{
+ // When entropy is specified, we should see at least one high R signature within 20 signatures
+ CKey key = DecodeSecret(strSecret1);
+ std::string msg = "A message to be signed";
+ uint256 msg_hash = Hash(msg.begin(), msg.end());
+ std::vector<unsigned char> sig;
+ bool found = false;
+
+ for (int i = 1; i <=20; ++i) {
+ sig.clear();
+ key.Sign(msg_hash, sig, false, i);
+ found = sig[3] == 0x21 && sig[4] == 0x00;
+ if (found) {
+ break;
+ }
+ }
+ BOOST_CHECK(found);
+
+ // When entropy is not specified, we should always see low R signatures that are less than 70 bytes in 256 tries
+ // We should see at least one signature that is less than 70 bytes.
+ found = true;
+ bool found_small = false;
+ for (int i = 0; i < 256; ++i) {
+ sig.clear();
+ std::string msg = "A message to be signed" + std::to_string(i);
+ msg_hash = Hash(msg.begin(), msg.end());
+ key.Sign(msg_hash, sig);
+ found = sig[3] == 0x20;
+ BOOST_CHECK(sig.size() <= 70);
+ found_small |= sig.size() < 70;
+ }
+ BOOST_CHECK(found);
+ BOOST_CHECK(found_small);
+}
+
BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index e56080b278..bc671394c0 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -369,7 +369,7 @@ public:
std::vector<unsigned char> vchSig, r, s;
uint32_t iter = 0;
do {
- key.Sign(hash, vchSig, iter++);
+ key.Sign(hash, vchSig, false, iter++);
if ((lenS == 33) != (vchSig[5 + vchSig[3]] == 33)) {
NegateSignatureS(vchSig);
}
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 73d2b205c2..5a7fdf9a85 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1542,30 +1542,29 @@ int64_t CWalletTx::GetTxTime() const
return n ? n : nTimeReceived;
}
-// Helper for producing a max-sized low-S signature (eg 72 bytes)
-bool CWallet::DummySignInput(CTxIn &tx_in, const CTxOut &txout) const
+// Helper for producing a max-sized low-S low-R signature (eg 71 bytes)
+// or a max-sized low-S signature (e.g. 72 bytes) if use_max_sig is true
+bool CWallet::DummySignInput(CTxIn &tx_in, const CTxOut &txout, bool use_max_sig) const
{
// Fill in dummy signatures for fee calculation.
const CScript& scriptPubKey = txout.scriptPubKey;
SignatureData sigdata;
- if (!ProduceSignature(*this, DUMMY_SIGNATURE_CREATOR, scriptPubKey, sigdata))
- {
+ if (!ProduceSignature(*this, use_max_sig ? DUMMY_MAXIMUM_SIGNATURE_CREATOR : DUMMY_SIGNATURE_CREATOR, scriptPubKey, sigdata)) {
return false;
- } else {
- UpdateInput(tx_in, sigdata);
}
+ UpdateInput(tx_in, sigdata);
return true;
}
-// Helper for producing a bunch of max-sized low-S signatures (eg 72 bytes)
-bool CWallet::DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts) const
+// Helper for producing a bunch of max-sized low-S low-R signatures (eg 71 bytes)
+bool CWallet::DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts, bool use_max_sig) const
{
// Fill in dummy signatures for fee calculation.
int nIn = 0;
for (const auto& txout : txouts)
{
- if (!DummySignInput(txNew.vin[nIn], txout)) {
+ if (!DummySignInput(txNew.vin[nIn], txout, use_max_sig)) {
return false;
}
@@ -1574,7 +1573,7 @@ bool CWallet::DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut>
return true;
}
-int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet)
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, bool use_max_sig)
{
std::vector<CTxOut> txouts;
// Look up the inputs. We should have already checked that this transaction
@@ -1588,14 +1587,14 @@ int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wall
assert(input.prevout.n < mi->second.tx->vout.size());
txouts.emplace_back(mi->second.tx->vout[input.prevout.n]);
}
- return CalculateMaximumSignedTxSize(tx, wallet, txouts);
+ return CalculateMaximumSignedTxSize(tx, wallet, txouts, use_max_sig);
}
// txouts needs to be in the order of tx.vin
-int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts)
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts, bool use_max_sig)
{
CMutableTransaction txNew(tx);
- if (!wallet->DummySignTx(txNew, txouts)) {
+ if (!wallet->DummySignTx(txNew, txouts, use_max_sig)) {
// This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
// implies that we can sign for every input.
return -1;
@@ -1603,11 +1602,11 @@ int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wall
return GetVirtualTransactionSize(txNew);
}
-int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* wallet)
+int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* wallet, bool use_max_sig)
{
CMutableTransaction txn;
txn.vin.push_back(CTxIn(COutPoint()));
- if (!wallet->DummySignInput(txn.vin[0], txout)) {
+ if (!wallet->DummySignInput(txn.vin[0], txout, use_max_sig)) {
// This should never happen, because IsAllFromMe(ISMINE_SPENDABLE)
// implies that we can sign for every input.
return -1;
@@ -2334,7 +2333,7 @@ void CWallet::AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe, const
bool solvable = IsSolvable(*this, pcoin->tx->vout[i].scriptPubKey);
bool spendable = ((mine & ISMINE_SPENDABLE) != ISMINE_NO) || (((mine & ISMINE_WATCH_ONLY) != ISMINE_NO) && (coinControl && coinControl->fAllowWatchOnly && solvable));
- vCoins.push_back(COutput(pcoin, i, nDepth, spendable, solvable, safeTx));
+ vCoins.push_back(COutput(pcoin, i, nDepth, spendable, solvable, safeTx, (coinControl && coinControl->fAllowWatchOnly)));
// Checks the sum amount of all UTXO's.
if (nMinimumSumAmount != MAX_MONEY) {
@@ -2889,7 +2888,7 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CTransac
txNew.vin.push_back(CTxIn(coin.outpoint,CScript()));
}
- nBytes = CalculateMaximumSignedTxSize(txNew, this);
+ nBytes = CalculateMaximumSignedTxSize(txNew, this, coin_control.fAllowWatchOnly);
if (nBytes < 0) {
strFailReason = _("Signing transaction failed");
return false;
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index ab3e38e807..57b22c0e49 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -276,7 +276,7 @@ public:
};
//Get the marginal bytes of spending the specified output
-int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet);
+int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet, bool use_max_sig = false);
/**
* A transaction with a bunch of additional info that only the owner cares about.
@@ -461,9 +461,9 @@ public:
CAmount GetChange() const;
// Get the marginal bytes if spending the specified output from this transaction
- int GetSpendSize(unsigned int out) const
+ int GetSpendSize(unsigned int out, bool use_max_sig = false) const
{
- return CalculateMaximumSignedInputSize(tx->vout[out], pwallet);
+ return CalculateMaximumSignedInputSize(tx->vout[out], pwallet, use_max_sig);
}
void GetAmounts(std::list<COutputEntry>& listReceived,
@@ -507,6 +507,9 @@ public:
/** Whether we know how to spend this output, ignoring the lack of keys */
bool fSolvable;
+ /** Whether to use the maximum sized, 72 byte signature when calculating the size of the input spend. This should only be set when watch-only outputs are allowed */
+ bool use_max_sig;
+
/**
* Whether this output is considered safe to spend. Unconfirmed transactions
* from outside keys and unconfirmed replacement transactions are considered
@@ -514,13 +517,13 @@ public:
*/
bool fSafe;
- COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn, bool fSolvableIn, bool fSafeIn)
+ COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn, bool fSolvableIn, bool fSafeIn, bool use_max_sig_in = false)
{
- tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn; nInputBytes = -1;
+ tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn; nInputBytes = -1; use_max_sig = use_max_sig_in;
// If known and signable by the given wallet, compute nInputBytes
// Failure will keep this value -1
if (fSpendable && tx) {
- nInputBytes = tx->GetSpendSize(i);
+ nInputBytes = tx->GetSpendSize(i, use_max_sig);
}
}
@@ -976,14 +979,14 @@ public:
void ListAccountCreditDebit(const std::string& strAccount, std::list<CAccountingEntry>& entries);
bool AddAccountingEntry(const CAccountingEntry&);
bool AddAccountingEntry(const CAccountingEntry&, WalletBatch *batch);
- bool DummySignTx(CMutableTransaction &txNew, const std::set<CTxOut> &txouts) const
+ bool DummySignTx(CMutableTransaction &txNew, const std::set<CTxOut> &txouts, bool use_max_sig = false) const
{
std::vector<CTxOut> v_txouts(txouts.size());
std::copy(txouts.begin(), txouts.end(), v_txouts.begin());
- return DummySignTx(txNew, v_txouts);
+ return DummySignTx(txNew, v_txouts, use_max_sig);
}
- bool DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts) const;
- bool DummySignInput(CTxIn &tx_in, const CTxOut &txout) const;
+ bool DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts, bool use_max_sig = false) const;
+ bool DummySignInput(CTxIn &tx_in, const CTxOut &txout, bool use_max_sig = false) const;
CFeeRate m_pay_tx_fee{DEFAULT_PAY_TX_FEE};
unsigned int m_confirm_target{DEFAULT_TX_CONFIRM_TARGET};
@@ -1308,9 +1311,9 @@ public:
};
// Calculate the size of the transaction assuming all signatures are max size
-// Use DummySignatureCreator, which inserts 72 byte signatures everywhere.
+// Use DummySignatureCreator, which inserts 71 byte signatures everywhere.
// NOTE: this requires that all inputs must be in mapWallet (eg the tx should
// be IsAllFromMe).
-int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet);
-int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts);
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, bool use_max_sig = false);
+int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts, bool use_max_sig = false);
#endif // BITCOIN_WALLET_WALLET_H
generated by cgit v1.2.3 (git 2.26.2) at 2024-10-31 19:55:15 +0000