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-rw-r--r--src/key.cpp68
1 files changed, 68 insertions, 0 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;
}