carrot_core [3/27/2025]

2024-11-08 14:33:54 -06:00
parent 9292f88a57
commit ed030081b7
45 changed files with 7505 additions and 2 deletions
@@ -0,0 +1,185 @@
+// Copyright (c) 2024, 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.
+
+// Transcript class for assembling data that needs to be hashed.
+
+#pragma once
+
+//local headers
+#include "int-util.h"
+#include "memwipe.h"
+
+//third party headers
+
+//standard headers
+#include <cstddef>
+#include <string>
+#include <type_traits>
+
+//forward declarations
+
+
+namespace sp
+{
+namespace detail
+{
+template <typename... Ts>
+constexpr size_t sizeof_sum()
+{
+    return (sizeof(Ts) + ...);
+}
+
+template <>
+constexpr size_t sizeof_sum<>()
+{
+    return 0;
+}
+} //namespace detail
+
+////
+// SpFixedTranscript
+// - build a transcript of a fixed bytesize and input types, enforced at compile time
+// - written to be the simplest correct transcript of data possible
+// - requires domain separators at compile-time as well
+// - ensures that no two transcripts with different domain separators will ever be equal
+// - does not use dynamic allocation
+// - unsigned integers are added to the transcript in little-endian form
+// - signed integers are not allowed
+// - domain separator is length-prefixed with a single unsigned byte at the beginning
+// - passed domain separator can be null terminated or not, null bytes and after will be dropped
+///
+template <std::size_t N, const unsigned char domain_sep[N], typename... Ts>
+class SpFixedTranscript final
+{
+public:
+//constructors
+    /// normal constructor
+    SpFixedTranscript(const Ts&... args)
+    {
+        // copy domain separator length prefix
+        m_transcript[0] = static_cast<unsigned char>(domain_sep_size());
+
+        // copy domain separator
+        memcpy(m_transcript + 1, domain_sep, domain_sep_size());
+
+        // copy types into buffer
+        append<1 + domain_sep_size()>(args...);
+    }
+
+//overloaded operators
+    /// disable copy/move
+    SpFixedTranscript& operator=(const SpFixedTranscript&) = delete;
+    SpFixedTranscript& operator=(SpFixedTranscript&&) = delete;
+
+//member functions
+    constexpr const void* data() const noexcept { return m_transcript; }
+
+    static constexpr std::size_t size()
+    {
+        return 1 + domain_sep_size() + detail::sizeof_sum<Ts...>();
+    }
+
+//destructors
+    ~SpFixedTranscript()
+    {
+        // wipe the buffer on leave in case it contains sensitive data
+        memwipe(m_transcript, sizeof(m_transcript));
+    }
+
+private:
+//member functions
+    template <std::size_t>
+    void append() {}
+
+    template <std::size_t offset, typename U0, typename... Us>
+    void append(const U0 &arg0, const Us&... args)
+    {
+        // write current argument to buffer
+        write<offset>(arg0);
+
+        // call append for next argument
+        static constexpr size_t new_offset = offset + sizeof(arg0);
+        append<new_offset>(args...);
+    }
+
+    template <std::size_t offset, typename U>
+    void write(const U &val)
+    {
+        static_assert(std::has_unique_object_representations_v<U>);
+        static_assert(std::is_standard_layout_v<U>);
+        static_assert(!std::is_signed_v<U> || std::is_same_v<U, char>);
+        static_assert(alignof(U) == 1);
+        static_assert(!std::is_pointer_v<U>);
+
+        memcpy(m_transcript + offset, &val, sizeof(val));
+    }
+
+    template <std::size_t offset>
+    void write(std::uint16_t val)
+    {
+        val = SWAP16LE(val);
+        memcpy(m_transcript + offset, &val, sizeof(val));
+    }
+
+    template <std::size_t offset>
+    void write(std::uint32_t val)
+    {
+        val = SWAP32LE(val);
+        memcpy(m_transcript + offset, &val, sizeof(val));
+    }
+
+    template <std::size_t offset>
+    void write(std::uint64_t val)
+    {
+        val = SWAP64LE(val);
+        memcpy(m_transcript + offset, &val, sizeof(val));
+    }
+
+    static constexpr std::size_t domain_sep_size()
+    {
+        for (std::size_t i = 0; i < N; ++i)
+            if (domain_sep[i] == '\0')
+                return i;
+
+        return N;
+    }
+
+    static_assert(domain_sep_size() <= 255, "domain separator must be less than 256 characters long");
+
+//member variables
+    /// the transcript buffer
+    unsigned char m_transcript[size()];
+};
+
+template <const auto & domain_sep, typename... Ts>
+auto make_fixed_transcript(const Ts&... args)
+{
+    return SpFixedTranscript<std::size(domain_sep), domain_sep, Ts...>(args...);
+}
+
+} //namespace sp