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-rw-r--r--src/key.cpp68
-rw-r--r--src/test/DoS_tests.cpp93
2 files changed, 160 insertions, 1 deletions
diff --git a/src/key.cpp b/src/key.cpp
index ece835d147..ac7ac4db77 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -2,10 +2,14 @@
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+#include <map>
+
+#include <boost/tuple/tuple.hpp>
#include <openssl/ecdsa.h>
#include <openssl/obj_mac.h>
#include "key.h"
+#include "util.h"
// Generate a private key from just the secret parameter
int EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key)
@@ -347,21 +351,85 @@ bool CKey::SetCompactSignature(uint256 hash, const std::vector<unsigned char>& v
return false;
}
+// Valid signature cache, to avoid doing expensive ECDSA signature checking
+// twice for every transaction (once when accepted into memory pool, and
+// again when accepted into the block chain)
+
+// sigdata_type is (signature hash, signature, public key):
+typedef boost::tuple<uint256, std::vector<unsigned char>, std::vector<unsigned char> > sigdata_type;
+static std::set< sigdata_type> setValidSigCache;
+static CCriticalSection cs_sigcache;
+
+static bool
+GetValidSigCache(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
+{
+ LOCK(cs_sigcache);
+
+ sigdata_type k(hash, vchSig, pubKey);
+ std::set<sigdata_type>::iterator mi = setValidSigCache.find(k);
+ if (mi != setValidSigCache.end())
+ return true;
+ return false;
+}
+
+static void
+SetValidSigCache(uint256 hash, const std::vector<unsigned char>& vchSig, const std::vector<unsigned char>& pubKey)
+{
+ // DoS prevention: limit cache size to less than 10MB
+ // (~200 bytes per cache entry times 50,000 entries)
+ // Since there are a maximum of 20,000 signature operations per block
+ // 50,000 is a reasonable default.
+ int64 nMaxCacheSize = GetArg("-maxsigcachesize", 50000);
+ if (nMaxCacheSize <= 0) return;
+
+ LOCK(cs_sigcache);
+
+ while (setValidSigCache.size() > nMaxCacheSize)
+ {
+ // Evict a random entry. Random because that helps
+ // foil would-be DoS attackers who might try to pre-generate
+ // and re-use a set of valid signatures just-slightly-greater
+ // than our cache size.
+ uint256 randomHash = GetRandHash();
+ std::vector<unsigned char> unused;
+ std::set<sigdata_type>::iterator it =
+ setValidSigCache.lower_bound(sigdata_type(randomHash, unused, unused));
+ if (it == setValidSigCache.end())
+ it = setValidSigCache.begin();
+ setValidSigCache.erase(*it);
+ }
+
+ sigdata_type k(hash, vchSig, pubKey);
+ setValidSigCache.insert(k);
+}
+
+
bool CKey::Verify(uint256 hash, const std::vector<unsigned char>& vchSig)
{
+ if (GetValidSigCache(hash, vchSig, GetPubKey()))
+ return true;
+
// -1 = error, 0 = bad sig, 1 = good
if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1)
return false;
+
+ // good sig
+ SetValidSigCache(hash, vchSig, GetPubKey());
return true;
}
bool CKey::VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
{
+ if (GetValidSigCache(hash, vchSig, GetPubKey()))
+ return true;
+
CKey key;
if (!key.SetCompactSignature(hash, vchSig))
return false;
if (GetPubKey() != key.GetPubKey())
return false;
+
+ SetValidSigCache(hash, vchSig, GetPubKey());
return true;
}
diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp
index c0d414d083..4ee2e94834 100644
--- a/src/test/DoS_tests.cpp
+++ b/src/test/DoS_tests.cpp
@@ -1,7 +1,10 @@
//
// Unit tests for denial-of-service detection/prevention code
//
+#include <algorithm>
+
#include <boost/assign/list_of.hpp> // for 'map_list_of()'
+#include <boost/date_time/posix_time/posix_time_types.hpp>
#include <boost/test/unit_test.hpp>
#include <boost/foreach.hpp>
@@ -57,7 +60,7 @@ BOOST_AUTO_TEST_CASE(DoS_banscore)
BOOST_CHECK(!CNode::IsBanned(addr1));
dummyNode1.Misbehaving(1);
BOOST_CHECK(CNode::IsBanned(addr1));
- mapArgs["-banscore"] = "100";
+ mapArgs.erase("-banscore");
}
BOOST_AUTO_TEST_CASE(DoS_bantime)
@@ -220,4 +223,92 @@ BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
BOOST_CHECK(mapOrphanTransactionsByPrev.empty());
}
+BOOST_AUTO_TEST_CASE(DoS_checkSig)
+{
+ // Test signature caching code (see key.cpp Verify() methods)
+
+ CKey key;
+ key.MakeNewKey(true);
+ CBasicKeyStore keystore;
+ keystore.AddKey(key);
+
+ // 100 orphan transactions:
+ static const int NPREV=100;
+ CTransaction orphans[NPREV];
+ for (int i = 0; i < NPREV; i++)
+ {
+ CTransaction& tx = orphans[i];
+ tx.vin.resize(1);
+ tx.vin[0].prevout.n = 0;
+ tx.vin[0].prevout.hash = GetRandHash();
+ tx.vin[0].scriptSig << OP_1;
+ tx.vout.resize(1);
+ tx.vout[0].nValue = 1*CENT;
+ tx.vout[0].scriptPubKey.SetBitcoinAddress(key.GetPubKey());
+
+ CDataStream ds(SER_DISK, CLIENT_VERSION);
+ ds << tx;
+ AddOrphanTx(ds);
+ }
+
+ // Create a transaction that depends on orphans:
+ CTransaction tx;
+ tx.vout.resize(1);
+ tx.vout[0].nValue = 1*CENT;
+ tx.vout[0].scriptPubKey.SetBitcoinAddress(key.GetPubKey());
+ tx.vin.resize(NPREV);
+ for (int j = 0; j < tx.vin.size(); j++)
+ {
+ tx.vin[j].prevout.n = 0;
+ tx.vin[j].prevout.hash = orphans[j].GetHash();
+ }
+ // Creating signatures primes the cache:
+ boost::posix_time::ptime mst1 = boost::posix_time::microsec_clock::local_time();
+ for (int j = 0; j < tx.vin.size(); j++)
+ BOOST_CHECK(SignSignature(keystore, orphans[j], tx, j));
+ boost::posix_time::ptime mst2 = boost::posix_time::microsec_clock::local_time();
+ boost::posix_time::time_duration msdiff = mst2 - mst1;
+ long nOneValidate = msdiff.total_milliseconds();
+ if (fDebug) printf("DoS_Checksig sign: %ld\n", nOneValidate);
+
+ // ... now validating repeatedly should be quick:
+ // 2.8GHz machine, -g build: Sign takes ~760ms,
+ // uncached Verify takes ~250ms, cached Verify takes ~50ms
+ // (for 100 single-signature inputs)
+ mst1 = boost::posix_time::microsec_clock::local_time();
+ for (int i = 0; i < 5; i++)
+ for (int j = 0; j < tx.vin.size(); j++)
+ BOOST_CHECK(VerifySignature(orphans[j], tx, j, true, SIGHASH_ALL));
+ mst2 = boost::posix_time::microsec_clock::local_time();
+ msdiff = mst2 - mst1;
+ long nManyValidate = msdiff.total_milliseconds();
+ if (fDebug) printf("DoS_Checksig five: %ld\n", nManyValidate);
+
+ BOOST_CHECK_MESSAGE(nManyValidate < nOneValidate, "Signature cache timing failed");
+
+ // Empty a signature, validation should fail:
+ CScript save = tx.vin[0].scriptSig;
+ tx.vin[0].scriptSig = CScript();
+ BOOST_CHECK(!VerifySignature(orphans[0], tx, 0, true, SIGHASH_ALL));
+ tx.vin[0].scriptSig = save;
+
+ // Swap signatures, validation should fail:
+ std::swap(tx.vin[0].scriptSig, tx.vin[1].scriptSig);
+ BOOST_CHECK(!VerifySignature(orphans[0], tx, 0, true, SIGHASH_ALL));
+ BOOST_CHECK(!VerifySignature(orphans[1], tx, 1, true, SIGHASH_ALL));
+ std::swap(tx.vin[0].scriptSig, tx.vin[1].scriptSig);
+
+ // Exercise -maxsigcachesize code:
+ mapArgs["-maxsigcachesize"] = "10";
+ // Generate a new, different signature for vin[0] to trigger cache clear:
+ CScript oldSig = tx.vin[0].scriptSig;
+ BOOST_CHECK(SignSignature(keystore, orphans[0], tx, 0));
+ BOOST_CHECK(tx.vin[0].scriptSig != oldSig);
+ for (int j = 0; j < tx.vin.size(); j++)
+ BOOST_CHECK(VerifySignature(orphans[j], tx, j, true, SIGHASH_ALL));
+ mapArgs.erase("-maxsigcachesize");
+
+ LimitOrphanTxSize(0);
+}
+
BOOST_AUTO_TEST_SUITE_END()
generated by cgit v1.2.3 (git 2.26.2) at 2024-08-20 19:39:49 +0000