'--verify-update', shasum support, OpenPGP signatures verification

src/openpgp/serialization.h

@@ -0,0 +1,171 @@
+// Copyright (c) 2020, 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 "mpi.h"
+
+namespace openpgp
+{
+
+size_t bits_to_bytes(size_t bits)
+{
+  constexpr const uint16_t bits_in_byte = 8;
+  return (bits + bits_in_byte - 1) / bits_in_byte;
+}
+
+std::string strip_line_breaks(const std::string &string)
+{
+  std::string result;
+  result.reserve(string.size());
+  for (const auto &character : string)
+  {
+    if (character != '\r' && character != '\n')
+    {
+      result.push_back(character);
+    }
+  }
+  return result;
+}
+
+struct packet_tag
+{
+  enum type : uint8_t
+  {
+    signature = 2,
+    public_key = 6,
+    user_id = 13,
+  };
+
+  const type packet_type;
+  const size_t length;
+};
+
+template <
+  typename byte_container,
+  typename = typename std::enable_if<(sizeof(typename byte_container::value_type) == 1)>::type>
+class deserializer
+{
+public:
+  deserializer(byte_container buffer)
+    : buffer(std::move(buffer))
+    , cursor(0)
+  {
+  }
+
+  bool empty() const
+  {
+    return buffer.size() - cursor == 0;
+  }
+
+  packet_tag read_packet_tag()
+  {
+    const auto tag = read_big_endian<uint8_t>();
+
+    constexpr const uint8_t format_mask = 0b11000000;
+    constexpr const uint8_t format_old_tag = 0b10000000;
+    if ((tag & format_mask) != format_old_tag)
+    {
+      throw std::runtime_error("invalid packet tag");
+    }
+
+    const packet_tag::type packet_type = static_cast<packet_tag::type>((tag & 0b00111100) >> 2);
+    const uint8_t length_type = tag & 0b00000011;
+
+    size_t length;
+    switch (length_type)
+    {
+    case 0:
+      length = read_big_endian<uint8_t>();
+      break;
+    case 1:
+      length = read_big_endian<uint16_t>();
+      break;
+    case 2:
+      length = read_big_endian<uint32_t>();
+      break;
+    default:
+      throw std::runtime_error("unsupported packet length type");
+    }
+
+    return {packet_type, length};
+  }
+
+  mpi read_mpi()
+  {
+    const size_t bit_length = read_big_endian<uint16_t>();
+    return mpi(read_span(bits_to_bytes(bit_length)));
+  }
+
+  std::vector<uint8_t> read(size_t size)
+  {
+    if (buffer.size() - cursor < size)
+    {
+      throw std::runtime_error("insufficient buffer size");
+    }
+
+    const size_t offset = cursor;
+    cursor += size;
+
+    return {&buffer[offset], &buffer[cursor]};
+  }
+
+  template <typename T, typename = typename std::enable_if<std::is_integral<T>::value>::type>
+  T read_big_endian()
+  {
+    if (buffer.size() - cursor < sizeof(T))
+    {
+      throw std::runtime_error("insufficient buffer size");
+    }
+    T result = 0;
+    for (size_t read = 0; read < sizeof(T); ++read)
+    {
+      result = (result << 8) | static_cast<uint8_t>(buffer[cursor++]);
+    }
+    return result;
+  }
+
+  epee::span<const uint8_t> read_span(size_t size)
+  {
+    if (buffer.size() - cursor < size)
+    {
+      throw std::runtime_error("insufficient buffer size");
+    }
+
+    const size_t offset = cursor;
+    cursor += size;
+
+    return {reinterpret_cast<const uint8_t *>(&buffer[offset]), size};
+  }
+
+private:
+  byte_container buffer;
+  size_t cursor;
+};
+
+} // namespace openpgp