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Differential D2373 Diff 6947 src/script/sigcache.cpp

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src/script/sigcache.cpp

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#include "uint256.h" #include "uint256.h"
#include "util.h" #include "util.h"
#include <boost/thread/shared_mutex.hpp> #include <boost/thread/shared_mutex.hpp>
namespace { namespace {
/** /**
* Declare which flags absolutely do not affect VerifySignature() result.
* The caching code in sighash.cpp uses this to reduce unnecessary cache
markblundebergAuthorUnsubmitted
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note to self -- mentions "sighash.cpp" which is misspelled and needlessly self-referential here

markblundeberg: note to self -- mentions "sighash.cpp" which is misspelled and needlessly self-referential here
* misses (such as when policy and consensus flags differ on unrelated
* aspects).
*/
static const uint32_t INVARIANT_FLAGS =
SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC | SCRIPT_VERIFY_DERSIG |
SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_NULLDUMMY | SCRIPT_VERIFY_SIGPUSHONLY |
SCRIPT_VERIFY_MINIMALDATA | SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
SCRIPT_VERIFY_CLEANSTACK | SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY |
SCRIPT_VERIFY_CHECKSEQUENCEVERIFY | SCRIPT_VERIFY_MINIMALIF |
SCRIPT_VERIFY_NULLFAIL | SCRIPT_VERIFY_COMPRESSED_PUBKEYTYPE |
SCRIPT_ENABLE_SIGHASH_FORKID | SCRIPT_ENABLE_REPLAY_PROTECTION |
SCRIPT_ENABLE_CHECKDATASIG;
/**
* Valid signature cache, to avoid doing expensive ECDSA signature checking * Valid signature cache, to avoid doing expensive ECDSA signature checking
* twice for every transaction (once when accepted into memory pool, and * twice for every transaction (once when accepted into memory pool, and
* again when accepted into the block chain) * again when accepted into the block chain)
*/ */
class CSignatureCache { class CSignatureCache {
private: private:
//! Entries are SHA256(nonce || signature hash || public key || signature): //! Entries are SHA256(nonce || signature || public key || signature hash ||
//! flags):
uint256 nonce; uint256 nonce;
typedef CuckooCache::cache<uint256, SignatureCacheHasher> map_type; typedef CuckooCache::cache<uint256, SignatureCacheHasher> map_type;
map_type setValid; map_type setValid;
boost::shared_mutex cs_sigcache; boost::shared_mutex cs_sigcache;
public: public:
CSignatureCache() { GetRandBytes(nonce.begin(), 32); } CSignatureCache() { GetRandBytes(nonce.begin(), 32); }
void ComputeEntry(uint256 &entry, const uint256 &hash, void ComputeEntry(uint256 &entry, const std::vector<uint8_t> &vchSig,
const std::vector<uint8_t> &vchSig, const CPubKey &pubkey, const uint256 &hash,
const CPubKey &pubkey) { uint32_t flags) {
flags &= ~INVARIANT_FLAGS;
CSHA256() CSHA256()
.Write(nonce.begin(), 32) .Write(nonce.begin(), 32)
.Write(hash.begin(), 32)
.Write(&pubkey[0], pubkey.size())
.Write(&vchSig[0], vchSig.size()) .Write(&vchSig[0], vchSig.size())
.Write(&pubkey[0], pubkey.size())
.Write(hash.begin(), 32)
deadalnixUnsubmitted
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Why did you change the ordering ? I would keep the signature at the end as it is under user control.

deadalnix: Why did you change the ordering ? I would keep the signature at the end as it is under user…
markblundebergAuthorUnsubmitted
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Ordering was changed to follow the ordering of VerifySignature, which is getting memoized. But I can change it back if you prefer.

markblundeberg: Ordering was changed to follow the ordering of VerifySignature, which is getting memoized. But…
deadalnixUnsubmitted
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Yes, I do think it is better to keep the signature at the end. H(msg || pubkey || flags || sig) for instance.

deadalnix: Yes, I do think it is better to keep the signature at the end. H(msg || pubkey || flags || sig)…
.Write(reinterpret_cast<uint8_t *>(&flags), sizeof(flags))
.Finalize(entry.begin()); .Finalize(entry.begin());
} }
bool Get(const uint256 &entry, const bool erase) { bool Get(const uint256 &entry, const bool erase) {
boost::shared_lock<boost::shared_mutex> lock(cs_sigcache); boost::shared_lock<boost::shared_mutex> lock(cs_sigcache);
return setValid.contains(entry, erase); return setValid.contains(entry, erase);
} }
Show All 26 Linesvoid InitSignatureCache() {
size_t nElems = signatureCache.setup_bytes(nMaxCacheSize); size_t nElems = signatureCache.setup_bytes(nMaxCacheSize);
LogPrintf("Using %zu MiB out of %zu requested for signature cache, able to " LogPrintf("Using %zu MiB out of %zu requested for signature cache, able to "
"store %zu elements\n", "store %zu elements\n",
(nElems * sizeof(uint256)) >> 20, nMaxCacheSize >> 20, nElems); (nElems * sizeof(uint256)) >> 20, nMaxCacheSize >> 20, nElems);
} }
template <typename F> template <typename F>
bool RunMemoizedCheck(const std::vector<uint8_t> &vchSig, const CPubKey &pubkey, bool RunMemoizedCheck(const std::vector<uint8_t> &vchSig, const CPubKey &pubkey,
const uint256 &sighash, bool storeOrErase, const F &fun) { const uint256 &sighash, uint32_t flags, bool storeOrErase,
const F &fun) {
uint256 entry; uint256 entry;
signatureCache.ComputeEntry(entry, sighash, vchSig, pubkey); signatureCache.ComputeEntry(entry, vchSig, pubkey, sighash, flags);
if (signatureCache.Get(entry, !storeOrErase)) { if (signatureCache.Get(entry, !storeOrErase)) {
return true; return true;
} }
if (!fun()) { if (!fun()) {
return false; return false;
} }
if (storeOrErase) { if (storeOrErase) {
signatureCache.Set(entry); signatureCache.Set(entry);
} }
return true; return true;
} }
bool CachingTransactionSignatureChecker::IsCached( bool CachingTransactionSignatureChecker::IsCached(
const std::vector<uint8_t> &vchSig, const CPubKey &pubkey, const std::vector<uint8_t> &vchSig, const CPubKey &pubkey,
const uint256 &sighash) const { const uint256 &sighash, uint32_t flags) const {
return RunMemoizedCheck(vchSig, pubkey, sighash, true, return RunMemoizedCheck(vchSig, pubkey, sighash, flags, true,
[] { return false; }); [] { return false; });
} }
bool CachingTransactionSignatureChecker::VerifySignature( bool CachingTransactionSignatureChecker::VerifySignature(
const std::vector<uint8_t> &vchSig, const CPubKey &pubkey, const std::vector<uint8_t> &vchSig, const CPubKey &pubkey,
const uint256 &sighash) const { const uint256 &sighash, uint32_t flags) const {
return RunMemoizedCheck(vchSig, pubkey, sighash, store, [&] { return RunMemoizedCheck(vchSig, pubkey, sighash, flags, store, [&] {
return TransactionSignatureChecker::VerifySignature(vchSig, pubkey, return TransactionSignatureChecker::VerifySignature(vchSig, pubkey,
sighash); sighash, flags);
}); });
} }