verRctNonSemanticsSimpleCached: fix fragility

1 files changed, 78 insertions, 0 deletions

diff --git a/src/cryptonote_core/tx_verification_utils.h b/src/cryptonote_core/tx_verification_utils.h
new file mode 100644
index 000000000..ccd401d2a
--- /dev/null
+++ b/src/cryptonote_core/tx_verification_utils.h
@@ -0,0 +1,78 @@
+// Copyright (c) 2023, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include "common/data_cache.h"
+#include "cryptonote_basic/cryptonote_basic.h"
+
+namespace cryptonote
+{
+
+// Modifying this value should not affect consensus. You can adjust it for performance needs
+static constexpr const size_t RCT_VER_CACHE_SIZE = 8192;
+
+using rct_ver_cache_t = ::tools::data_cache<::crypto::hash, RCT_VER_CACHE_SIZE>;
+
+/**
+ * @brief Cached version of rct::verRctNonSemanticsSimple
+ *
+ * This function will not affect how the transaction is serialized and it will never modify the
+ * transaction prefix.
+ *
+ * The reference to tx is mutable since the transaction's ring signatures may be expanded by
+ * Blockchain::expand_transaction_2. However, on cache hits, the transaction will not be
+ * expanded. This means that the caller does not need to call expand_transaction_2 on this
+ * transaction before passing it; the transaction will not successfully verify with "old" RCT data
+ * if the transaction has been otherwise modified since the last verification.
+ *
+ * But, if cryptonote::get_transaction_hash(tx) returns a "stale" hash, this function is not
+ * guaranteed to work. So make sure that the cryptonote::transaction passed has not had
+ * modifications to it since the last time its hash was fetched without properly invalidating the
+ * hashes.
+ *
+ * rct_type_to_cache can be any RCT version value as long as rct::verRctNonSemanticsSimple works for
+ * this RCT version, but for most applications, it doesn't make sense to not make this version
+ * the "current" RCT version (i.e. the version that transactions in the mempool are).
+ *
+ * @param tx transaction which contains RCT signature to verify
+ * @param mix_ring mixring referenced by this tx. THIS DATA MUST BE PREVIOUSLY VALIDATED
+ * @param cache saves tx+mixring hashes used to cache calls
+ * @param rct_type_to_cache Only RCT sigs with version (e.g. RCTTypeBulletproofPlus) will be cached
+ * @return true when verRctNonSemanticsSimple() w/ expanded tx.rct_signatures would return true
+ * @return false when verRctNonSemanticsSimple() w/ expanded tx.rct_signatures would return false
+ */
+bool ver_rct_non_semantics_simple_cached
+(
+    transaction& tx,
+    const rct::ctkeyM& mix_ring,
+    rct_ver_cache_t& cache,
+    std::uint8_t rct_type_to_cache
+);
+
+} // namespace cryptonote