mirror of https://git.matrix.org/git/olm.git
142 lines
3.7 KiB
C++
142 lines
3.7 KiB
C++
/* Copyright 2015 OpenMarket Ltd
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* functions for encoding and decoding messages in the Olm protocol.
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*
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* Some of these functions have plain-C bindings, and are declared in
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* message.h; in time, all of the functions declared here should probably be
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* converted to plain C and moved to message.h.
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*/
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#include "message.h"
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#include <cstddef>
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#include <cstdint>
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// Note: exports in this file are only for unit tests. Nobody else should be
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// using this externally
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#include "olm/olm_export.h"
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namespace olm {
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/**
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* The length of the buffer needed to hold a message.
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*/
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OLM_EXPORT std::size_t encode_message_length(
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std::uint32_t counter,
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std::size_t ratchet_key_length,
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std::size_t ciphertext_length,
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std::size_t mac_length
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);
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struct MessageWriter {
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std::uint8_t * ratchet_key;
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std::uint8_t * ciphertext;
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};
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struct MessageReader {
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std::uint8_t version;
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bool has_counter;
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std::uint32_t counter;
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std::uint8_t const * input; std::size_t input_length;
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std::uint8_t const * ratchet_key; std::size_t ratchet_key_length;
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std::uint8_t const * ciphertext; std::size_t ciphertext_length;
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};
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/**
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* Writes the message headers into the output buffer.
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* Populates the writer struct with pointers into the output buffer.
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*/
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OLM_EXPORT void encode_message(
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MessageWriter & writer,
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std::uint8_t version,
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std::uint32_t counter,
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std::size_t ratchet_key_length,
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std::size_t ciphertext_length,
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std::uint8_t * output
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);
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/**
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* Reads the message headers from the input buffer.
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* Populates the reader struct with pointers into the input buffer.
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*/
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OLM_EXPORT void decode_message(
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MessageReader & reader,
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std::uint8_t const * input, std::size_t input_length,
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std::size_t mac_length
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);
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struct PreKeyMessageWriter {
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std::uint8_t * identity_key;
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std::uint8_t * base_key;
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std::uint8_t * one_time_key;
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std::uint8_t * message;
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};
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struct PreKeyMessageReader {
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std::uint8_t version;
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std::uint8_t const * identity_key; std::size_t identity_key_length;
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std::uint8_t const * base_key; std::size_t base_key_length;
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std::uint8_t const * one_time_key; std::size_t one_time_key_length;
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std::uint8_t const * message; std::size_t message_length;
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};
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/**
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* The length of the buffer needed to hold a message.
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*/
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std::size_t encode_one_time_key_message_length(
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std::size_t identity_key_length,
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std::size_t base_key_length,
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std::size_t one_time_key_length,
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std::size_t message_length
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);
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/**
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* Writes the message headers into the output buffer.
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* Populates the writer struct with pointers into the output buffer.
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*/
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void encode_one_time_key_message(
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PreKeyMessageWriter & writer,
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std::uint8_t version,
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std::size_t identity_key_length,
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std::size_t base_key_length,
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std::size_t one_time_key_length,
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std::size_t message_length,
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std::uint8_t * output
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);
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/**
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* Reads the message headers from the input buffer.
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* Populates the reader struct with pointers into the input buffer.
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*/
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void decode_one_time_key_message(
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PreKeyMessageReader & reader,
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std::uint8_t const * input, std::size_t input_length
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);
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} // namespace olm
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