Commit e533b0dc authored by Richard van der Hoff's avatar Richard van der Hoff
Browse files

Give SHA256 functions C bindings

parent 4f1bb49d
/* Copyright 2015 OpenMarket Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* C-compatible crpyto utility functions. At some point all of crypto.hh will
* move here.
*/
#ifndef OLM_CRYPTO_H_
#define OLM_CRYPTO_H_
#include <stdint.h>
#include <stdlib.h>
#ifdef __cplusplus
extern "C" {
#endif
const size_t SHA256_OUTPUT_LENGTH = 32;
/** Computes SHA-256 of the input. The output buffer must be a least 32
* bytes long. */
void crypto_sha256(
uint8_t const * input, size_t input_length,
uint8_t * output
);
/** HMAC: Keyed-Hashing for Message Authentication
* http://tools.ietf.org/html/rfc2104
* Computes HMAC-SHA-256 of the input for the key. The output buffer must
* be at least 32 bytes long. */
void crypto_hmac_sha256(
uint8_t const * key, size_t key_length,
uint8_t const * input, size_t input_length,
uint8_t * output
);
/** HMAC-based Key Derivation Function (HKDF)
* https://tools.ietf.org/html/rfc5869
* Derives key material from the input bytes. */
void crypto_hkdf_sha256(
uint8_t const * input, size_t input_length,
uint8_t const * info, size_t info_length,
uint8_t const * salt, size_t salt_length,
uint8_t * output, size_t output_length
);
#ifdef __cplusplus
} // extern "C"
#endif
#endif /* OLM_CRYPTO_H_ */
......@@ -18,6 +18,11 @@
#include <cstdint>
#include <cstddef>
// eventually all of this needs to move into crypto.h, and everything should
// use that. For now, include crypto.h here.
#include "olm/crypto.h"
namespace olm {
static const std::size_t KEY_LENGTH = 32;
......@@ -142,38 +147,6 @@ std::size_t aes_decrypt_cbc(
);
/** Computes SHA-256 of the input. The output buffer must be a least 32
* bytes long. */
void sha256(
std::uint8_t const * input, std::size_t input_length,
std::uint8_t * output
);
const std::size_t SHA256_OUTPUT_LENGTH = 32;
/** HMAC: Keyed-Hashing for Message Authentication
* http://tools.ietf.org/html/rfc2104
* Computes HMAC-SHA-256 of the input for the key. The output buffer must
* be at least 32 bytes long. */
void hmac_sha256(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t const * input, std::size_t input_length,
std::uint8_t * output
);
/** HMAC-based Key Derivation Function (HKDF)
* https://tools.ietf.org/html/rfc5869
* Derives key material from the input bytes. */
void hkdf_sha256(
std::uint8_t const * input, std::size_t input_length,
std::uint8_t const * info, std::size_t info_length,
std::uint8_t const * salt, std::size_t salt_length,
std::uint8_t * output, std::size_t output_length
);
} // namespace olm
#endif /* OLM_CRYPTO_HH_ */
......@@ -36,7 +36,7 @@ static void derive_keys(
DerivedKeys & keys
) {
std::uint8_t derived_secrets[2 * olm::KEY_LENGTH + olm::IV_LENGTH];
olm::hkdf_sha256(
crypto_hkdf_sha256(
key, key_length,
nullptr, 0,
kdf_info, kdf_info_length,
......@@ -83,7 +83,7 @@ std::size_t olm::CipherAesSha256::encrypt(
return std::size_t(-1);
}
struct DerivedKeys keys;
std::uint8_t mac[olm::SHA256_OUTPUT_LENGTH];
std::uint8_t mac[SHA256_OUTPUT_LENGTH];
derive_keys(kdf_info, kdf_info_length, key, key_length, keys);
......@@ -91,7 +91,7 @@ std::size_t olm::CipherAesSha256::encrypt(
keys.aes_key, keys.aes_iv, plaintext, plaintext_length, ciphertext
);
olm::hmac_sha256(
crypto_hmac_sha256(
keys.mac_key, olm::KEY_LENGTH, output, output_length - MAC_LENGTH, mac
);
......@@ -115,11 +115,11 @@ std::size_t olm::CipherAesSha256::decrypt(
std::uint8_t * plaintext, std::size_t max_plaintext_length
) const {
DerivedKeys keys;
std::uint8_t mac[olm::SHA256_OUTPUT_LENGTH];
std::uint8_t mac[SHA256_OUTPUT_LENGTH];
derive_keys(kdf_info, kdf_info_length, key, key_length, keys);
olm::hmac_sha256(
crypto_hmac_sha256(
keys.mac_key, olm::KEY_LENGTH, input, input_length - MAC_LENGTH, mac
);
......
......@@ -85,7 +85,7 @@ inline static void hmac_sha256_final(
std::uint8_t const * hmac_key,
std::uint8_t * output
) {
std::uint8_t o_pad[SHA256_BLOCK_LENGTH + olm::SHA256_OUTPUT_LENGTH];
std::uint8_t o_pad[SHA256_BLOCK_LENGTH + SHA256_OUTPUT_LENGTH];
std::memcpy(o_pad, hmac_key, SHA256_BLOCK_LENGTH);
for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
o_pad[i] ^= 0x5C;
......@@ -255,7 +255,7 @@ std::size_t olm::aes_decrypt_cbc(
}
void olm::sha256(
void crypto_sha256(
std::uint8_t const * input, std::size_t input_length,
std::uint8_t * output
) {
......@@ -267,7 +267,7 @@ void olm::sha256(
}
void olm::hmac_sha256(
void crypto_hmac_sha256(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t const * input, std::size_t input_length,
std::uint8_t * output
......@@ -283,7 +283,7 @@ void olm::hmac_sha256(
}
void olm::hkdf_sha256(
void crypto_hkdf_sha256(
std::uint8_t const * input, std::size_t input_length,
std::uint8_t const * salt, std::size_t salt_length,
std::uint8_t const * info, std::size_t info_length,
......@@ -291,7 +291,7 @@ void olm::hkdf_sha256(
) {
::SHA256_CTX context;
std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
std::uint8_t step_result[olm::SHA256_OUTPUT_LENGTH];
std::uint8_t step_result[SHA256_OUTPUT_LENGTH];
std::size_t bytes_remaining = output_length;
std::uint8_t iteration = 1;
if (!salt) {
......@@ -303,20 +303,20 @@ void olm::hkdf_sha256(
hmac_sha256_init(&context, hmac_key);
::sha256_update(&context, input, input_length);
hmac_sha256_final(&context, hmac_key, step_result);
hmac_sha256_key(step_result, olm::SHA256_OUTPUT_LENGTH, hmac_key);
hmac_sha256_key(step_result, SHA256_OUTPUT_LENGTH, hmac_key);
/* Expand */
hmac_sha256_init(&context, hmac_key);
::sha256_update(&context, info, info_length);
::sha256_update(&context, &iteration, 1);
hmac_sha256_final(&context, hmac_key, step_result);
while (bytes_remaining > olm::SHA256_OUTPUT_LENGTH) {
std::memcpy(output, step_result, olm::SHA256_OUTPUT_LENGTH);
output += olm::SHA256_OUTPUT_LENGTH;
bytes_remaining -= olm::SHA256_OUTPUT_LENGTH;
while (bytes_remaining > SHA256_OUTPUT_LENGTH) {
std::memcpy(output, step_result, SHA256_OUTPUT_LENGTH);
output += SHA256_OUTPUT_LENGTH;
bytes_remaining -= SHA256_OUTPUT_LENGTH;
iteration ++;
hmac_sha256_init(&context, hmac_key);
::sha256_update(&context, step_result, olm::SHA256_OUTPUT_LENGTH);
::sha256_update(&context, step_result, SHA256_OUTPUT_LENGTH);
::sha256_update(&context, info, info_length);
::sha256_update(&context, &iteration, 1);
hmac_sha256_final(&context, hmac_key, step_result);
......
......@@ -50,7 +50,7 @@ static void create_chain_key(
olm::SharedKey secret;
olm::curve25519_shared_secret(our_key, their_key, secret);
std::uint8_t derived_secrets[2 * olm::KEY_LENGTH];
olm::hkdf_sha256(
crypto_hkdf_sha256(
secret, sizeof(secret),
root_key, sizeof(root_key),
info.ratchet_info, info.ratchet_info_length,
......@@ -70,7 +70,7 @@ static void advance_chain_key(
olm::ChainKey const & chain_key,
olm::ChainKey & new_chain_key
) {
olm::hmac_sha256(
crypto_hmac_sha256(
chain_key.key, sizeof(chain_key.key),
CHAIN_KEY_SEED, sizeof(CHAIN_KEY_SEED),
new_chain_key.key
......@@ -84,7 +84,7 @@ static void create_message_keys(
olm::ChainKey const & chain_key,
olm::KdfInfo const & info,
olm::MessageKey & message_key) {
olm::hmac_sha256(
crypto_hmac_sha256(
chain_key.key, sizeof(chain_key.key),
MESSAGE_KEY_SEED, sizeof(MESSAGE_KEY_SEED),
message_key.key
......@@ -195,7 +195,7 @@ void olm::Ratchet::initialise_as_bob(
olm::Curve25519PublicKey const & their_ratchet_key
) {
std::uint8_t derived_secrets[2 * olm::KEY_LENGTH];
olm::hkdf_sha256(
crypto_hkdf_sha256(
shared_secret, shared_secret_length,
nullptr, 0,
kdf_info.root_info, kdf_info.root_info_length,
......@@ -217,7 +217,7 @@ void olm::Ratchet::initialise_as_alice(
olm::Curve25519KeyPair const & our_ratchet_key
) {
std::uint8_t derived_secrets[2 * olm::KEY_LENGTH];
olm::hkdf_sha256(
crypto_hkdf_sha256(
shared_secret, shared_secret_length,
nullptr, 0,
kdf_info.root_info, kdf_info.root_info_length,
......
......@@ -192,7 +192,7 @@ std::size_t olm::Session::new_inbound_session(
std::size_t olm::Session::session_id_length() {
return olm::SHA256_OUTPUT_LENGTH;
return SHA256_OUTPUT_LENGTH;
}
......@@ -208,7 +208,7 @@ std::size_t olm::Session::session_id(
pos = olm::store_array(pos, alice_identity_key.public_key);
pos = olm::store_array(pos, alice_base_key.public_key);
pos = olm::store_array(pos, bob_one_time_key.public_key);
olm::sha256(tmp, sizeof(tmp), id);
crypto_sha256(tmp, sizeof(tmp), id);
return session_id_length();
}
......
......@@ -23,7 +23,7 @@ olm::Utility::Utility(
size_t olm::Utility::sha256_length() {
return olm::SHA256_OUTPUT_LENGTH;
return SHA256_OUTPUT_LENGTH;
}
......@@ -35,8 +35,8 @@ size_t olm::Utility::sha256(
last_error = olm::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
return std::size_t(-1);
}
olm::sha256(input, input_length, output);
return olm::SHA256_OUTPUT_LENGTH;
crypto_sha256(input, input_length, output);
return SHA256_OUTPUT_LENGTH;
}
......
......@@ -186,7 +186,7 @@ std::uint8_t expected[32] = {
std::uint8_t actual[32];
olm::sha256(input, sizeof(input), actual);
crypto_sha256(input, sizeof(input), actual);
assert_equals(expected, actual, 32);
......@@ -207,7 +207,7 @@ std::uint8_t expected[32] = {
std::uint8_t actual[32];
olm::hmac_sha256(input, sizeof(input), input, sizeof(input), actual);
crypto_hmac_sha256(input, sizeof(input), input, sizeof(input), actual);
assert_equals(expected, actual, 32);
......@@ -242,7 +242,7 @@ std::uint8_t hmac_expected_output[32] = {
std::uint8_t hmac_actual_output[32] = {};
olm::hmac_sha256(
crypto_hmac_sha256(
salt, sizeof(salt),
input, sizeof(input),
hmac_actual_output
......@@ -261,7 +261,7 @@ std::uint8_t hkdf_expected_output[42] = {
std::uint8_t hkdf_actual_output[42] = {};
olm::hkdf_sha256(
crypto_hkdf_sha256(
input, sizeof(input),
salt, sizeof(salt),
info, sizeof(info),
......
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