25953b350b
This fixes an incorrect re-declaration of ed25519_sign. Implement header files for some of the other library bits so that we don't need to declare functions in crypto.cpp.
329 lines
9.9 KiB
C++
329 lines
9.9 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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#include "olm/crypto.hh"
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#include "olm/memory.hh"
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#include <cstring>
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extern "C" {
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#include "crypto-algorithms/aes.h"
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#include "crypto-algorithms/sha256.h"
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}
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#include "ed25519/src/ed25519.h"
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#include "ed25519_additions.h"
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#include "curve25519-donna.h"
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namespace {
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static const std::uint8_t CURVE25519_BASEPOINT[32] = {9};
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static const std::size_t AES_KEY_SCHEDULE_LENGTH = 60;
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static const std::size_t AES_KEY_BITS = 8 * olm::KEY_LENGTH;
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static const std::size_t AES_BLOCK_LENGTH = 16;
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static const std::size_t SHA256_BLOCK_LENGTH = 64;
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static const std::uint8_t HKDF_DEFAULT_SALT[32] = {};
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template<std::size_t block_size>
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inline static void xor_block(
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std::uint8_t * block,
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std::uint8_t const * input
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) {
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for (std::size_t i = 0; i < block_size; ++i) {
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block[i] ^= input[i];
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}
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}
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inline static void hmac_sha256_key(
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std::uint8_t const * input_key, std::size_t input_key_length,
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std::uint8_t * hmac_key
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) {
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std::memset(hmac_key, 0, SHA256_BLOCK_LENGTH);
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if (input_key_length > SHA256_BLOCK_LENGTH) {
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::SHA256_CTX context;
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::sha256_init(&context);
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::sha256_update(&context, input_key, input_key_length);
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::sha256_final(&context, hmac_key);
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} else {
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std::memcpy(hmac_key, input_key, input_key_length);
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}
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}
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inline static void hmac_sha256_init(
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::SHA256_CTX * context,
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std::uint8_t const * hmac_key
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) {
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std::uint8_t i_pad[SHA256_BLOCK_LENGTH];
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std::memcpy(i_pad, hmac_key, SHA256_BLOCK_LENGTH);
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for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
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i_pad[i] ^= 0x36;
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}
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::sha256_init(context);
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::sha256_update(context, i_pad, SHA256_BLOCK_LENGTH);
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olm::unset(i_pad);
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}
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inline static void hmac_sha256_final(
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::SHA256_CTX * context,
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std::uint8_t const * hmac_key,
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std::uint8_t * output
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) {
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std::uint8_t o_pad[SHA256_BLOCK_LENGTH + olm::SHA256_OUTPUT_LENGTH];
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std::memcpy(o_pad, hmac_key, SHA256_BLOCK_LENGTH);
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for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
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o_pad[i] ^= 0x5C;
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}
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::sha256_final(context, o_pad + SHA256_BLOCK_LENGTH);
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::SHA256_CTX final_context;
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::sha256_init(&final_context);
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::sha256_update(&final_context, o_pad, sizeof(o_pad));
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::sha256_final(&final_context, output);
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olm::unset(final_context);
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olm::unset(o_pad);
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}
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} // namespace
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void olm::curve25519_generate_key(
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std::uint8_t const * random_32_bytes,
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olm::Curve25519KeyPair & key_pair
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) {
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std::memcpy(key_pair.private_key, random_32_bytes, KEY_LENGTH);
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::curve25519_donna(
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key_pair.public_key, key_pair.private_key, CURVE25519_BASEPOINT
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);
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}
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void olm::curve25519_shared_secret(
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olm::Curve25519KeyPair const & our_key,
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olm::Curve25519PublicKey const & their_key,
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std::uint8_t * output
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) {
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::curve25519_donna(output, our_key.private_key, their_key.public_key);
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}
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void olm::curve25519_sign(
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olm::Curve25519KeyPair const & our_key,
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std::uint8_t const * message, std::size_t message_length,
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std::uint8_t * output
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) {
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std::uint8_t private_key[KEY_LENGTH];
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std::uint8_t public_key[KEY_LENGTH];
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std::memcpy(private_key, our_key.private_key, KEY_LENGTH);
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::ed25519_keypair(private_key, public_key);
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::ed25519_sign(
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output,
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message, message_length,
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public_key, private_key
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);
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::convert_ed25519_to_curve25519(public_key, output);
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}
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bool olm::curve25519_verify(
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olm::Curve25519PublicKey const & their_key,
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std::uint8_t const * message, std::size_t message_length,
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std::uint8_t const * signature
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) {
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std::uint8_t public_key[KEY_LENGTH];
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std::uint8_t signature_buffer[SIGNATURE_LENGTH];
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std::memcpy(public_key, their_key.public_key, KEY_LENGTH);
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std::memcpy(signature_buffer, signature, SIGNATURE_LENGTH);
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::convert_curve25519_to_ed25519(public_key, signature_buffer);
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return 0 != ::ed25519_verify(
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signature,
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message, message_length,
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public_key
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);
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}
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void olm::ed25519_generate_key(
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std::uint8_t const * random_32_bytes,
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olm::Ed25519KeyPair & key_pair
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) {
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std::memcpy(key_pair.private_key, random_32_bytes, KEY_LENGTH);
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::ed25519_keypair(key_pair.private_key, key_pair.public_key);
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}
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void olm::ed25519_sign(
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olm::Ed25519KeyPair const & our_key,
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std::uint8_t const * message, std::size_t message_length,
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std::uint8_t * output
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) {
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::ed25519_sign(
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output,
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message, message_length,
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our_key.public_key, our_key.private_key
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);
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}
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bool olm::ed25519_verify(
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olm::Ed25519PublicKey const & their_key,
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std::uint8_t const * message, std::size_t message_length,
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std::uint8_t const * signature
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) {
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return 0 != ::ed25519_verify(
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signature,
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message, message_length,
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their_key.public_key
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);
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}
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std::size_t olm::aes_encrypt_cbc_length(
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std::size_t input_length
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) {
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return input_length + AES_BLOCK_LENGTH - input_length % AES_BLOCK_LENGTH;
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}
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void olm::aes_encrypt_cbc(
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olm::Aes256Key const & key,
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olm::Aes256Iv const & iv,
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t * output
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) {
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std::uint32_t key_schedule[AES_KEY_SCHEDULE_LENGTH];
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::aes_key_setup(key.key, key_schedule, AES_KEY_BITS);
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std::uint8_t input_block[AES_BLOCK_LENGTH];
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std::memcpy(input_block, iv.iv, AES_BLOCK_LENGTH);
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while (input_length >= AES_BLOCK_LENGTH) {
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xor_block<AES_BLOCK_LENGTH>(input_block, input);
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::aes_encrypt(input_block, output, key_schedule, AES_KEY_BITS);
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std::memcpy(input_block, output, AES_BLOCK_LENGTH);
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input += AES_BLOCK_LENGTH;
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output += AES_BLOCK_LENGTH;
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input_length -= AES_BLOCK_LENGTH;
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}
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std::size_t i = 0;
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for (; i < input_length; ++i) {
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input_block[i] ^= input[i];
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}
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for (; i < AES_BLOCK_LENGTH; ++i) {
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input_block[i] ^= AES_BLOCK_LENGTH - input_length;
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}
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::aes_encrypt(input_block, output, key_schedule, AES_KEY_BITS);
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olm::unset(key_schedule);
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olm::unset(input_block);
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}
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std::size_t olm::aes_decrypt_cbc(
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olm::Aes256Key const & key,
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olm::Aes256Iv const & iv,
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t * output
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) {
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std::uint32_t key_schedule[AES_KEY_SCHEDULE_LENGTH];
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::aes_key_setup(key.key, key_schedule, AES_KEY_BITS);
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std::uint8_t block1[AES_BLOCK_LENGTH];
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std::uint8_t block2[AES_BLOCK_LENGTH];
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std::memcpy(block1, iv.iv, AES_BLOCK_LENGTH);
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for (std::size_t i = 0; i < input_length; i += AES_BLOCK_LENGTH) {
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std::memcpy(block2, &input[i], AES_BLOCK_LENGTH);
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::aes_decrypt(&input[i], &output[i], key_schedule, AES_KEY_BITS);
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xor_block<AES_BLOCK_LENGTH>(&output[i], block1);
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std::memcpy(block1, block2, AES_BLOCK_LENGTH);
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}
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olm::unset(key_schedule);
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olm::unset(block1);
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olm::unset(block2);
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std::size_t padding = output[input_length - 1];
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return (padding > input_length) ? std::size_t(-1) : (input_length - padding);
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}
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void olm::sha256(
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t * output
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) {
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::SHA256_CTX context;
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::sha256_init(&context);
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::sha256_update(&context, input, input_length);
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::sha256_final(&context, output);
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olm::unset(context);
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}
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void olm::hmac_sha256(
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std::uint8_t const * key, std::size_t key_length,
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t * output
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) {
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std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
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::SHA256_CTX context;
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hmac_sha256_key(key, key_length, hmac_key);
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hmac_sha256_init(&context, hmac_key);
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::sha256_update(&context, input, input_length);
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hmac_sha256_final(&context, hmac_key, output);
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olm::unset(hmac_key);
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olm::unset(context);
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}
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void olm::hkdf_sha256(
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std::uint8_t const * input, std::size_t input_length,
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std::uint8_t const * salt, std::size_t salt_length,
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std::uint8_t const * info, std::size_t info_length,
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std::uint8_t * output, std::size_t output_length
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) {
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::SHA256_CTX context;
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std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
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std::uint8_t step_result[olm::SHA256_OUTPUT_LENGTH];
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std::size_t bytes_remaining = output_length;
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std::uint8_t iteration = 1;
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if (!salt) {
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salt = HKDF_DEFAULT_SALT;
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salt_length = sizeof(HKDF_DEFAULT_SALT);
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}
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/* Expand */
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hmac_sha256_key(salt, salt_length, hmac_key);
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hmac_sha256_init(&context, hmac_key);
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::sha256_update(&context, input, input_length);
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hmac_sha256_final(&context, hmac_key, step_result);
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hmac_sha256_key(step_result, olm::SHA256_OUTPUT_LENGTH, hmac_key);
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/* Extract */
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hmac_sha256_init(&context, hmac_key);
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::sha256_update(&context, info, info_length);
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::sha256_update(&context, &iteration, 1);
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hmac_sha256_final(&context, hmac_key, step_result);
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while (bytes_remaining > olm::SHA256_OUTPUT_LENGTH) {
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std::memcpy(output, step_result, olm::SHA256_OUTPUT_LENGTH);
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output += olm::SHA256_OUTPUT_LENGTH;
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bytes_remaining -= olm::SHA256_OUTPUT_LENGTH;
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iteration ++;
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hmac_sha256_init(&context, hmac_key);
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::sha256_update(&context, step_result, olm::SHA256_OUTPUT_LENGTH);
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::sha256_update(&context, info, info_length);
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::sha256_update(&context, &iteration, 1);
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hmac_sha256_final(&context, hmac_key, step_result);
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}
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std::memcpy(output, step_result, bytes_remaining);
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olm::unset(context);
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olm::unset(hmac_key);
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olm::unset(step_result);
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}
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