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Rewrite _olm_cipher_aes_sha_256 initialisation

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Replace the init-static-var dance with some preprocessor macros
This commit is contained in:
Richard van der Hoff 2016-05-24 12:06:47 +01:00
parent d4a3c8dbaa
commit 2fd28a6682
5 changed files with 31 additions and 61 deletions
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31
include/olm/cipher.h
View file

@ -102,28 +102,33 @@ struct _olm_cipher {
struct _olm_cipher_aes_sha_256 {
struct _olm_cipher base_cipher;
/** context string for the HKDF used for deriving the AES256 key, HMAC key,
* and AES IV, from the key material passed to encrypt/decrypt.
*/
uint8_t const * kdf_info;
/** length of context string kdf_info */
size_t kdf_info_length;
};
extern const struct _olm_cipher_ops _olm_cipher_aes_sha_256_ops;
/**
* initialises a cipher type which uses AES256 for encryption and SHA256 for
* authentication.
* get an initializer for an instance of struct _olm_cipher_aes_sha_256.
*
* cipher: structure to be initialised
* To use it, declare:
*
* kdf_info: context string for the HKDF used for deriving the AES256 key, HMAC
* key, and AES IV, from the key material passed to encrypt/decrypt. Note that
* this is NOT copied so must have a lifetime at least as long as the cipher
* instance.
*
* kdf_info_length: length of context string kdf_info
* struct _olm_cipher_aes_sha_256 MY_CIPHER =
* OLM_CIPHER_INIT_AES_SHA_256("MY_KDF");
* struct _olm_cipher *cipher = OLM_CIPHER_BASE(&MY_CIPHER);
*/
struct _olm_cipher *_olm_cipher_aes_sha_256_init(
struct _olm_cipher_aes_sha_256 *cipher,
uint8_t const * kdf_info,
size_t kdf_info_length);
#define OLM_CIPHER_INIT_AES_SHA_256(KDF_INFO) { \
.base_cipher = { &_olm_cipher_aes_sha_256_ops },\
.kdf_info = (uint8_t *)(KDF_INFO), \
.kdf_info_length = sizeof(KDF_INFO) - 1 \
}
#define OLM_CIPHER_BASE(CIPHER) \
(&((CIPHER)->base_cipher))
#ifdef __cplusplus

17
src/cipher.cpp
View file

@ -130,25 +130,12 @@ size_t aes_sha_256_cipher_decrypt(
return plaintext_length;
}
} // namespace
const _olm_cipher_ops aes_sha_256_cipher_ops = {
const struct _olm_cipher_ops _olm_cipher_aes_sha_256_ops = {
aes_sha_256_cipher_mac_length,
aes_sha_256_cipher_encrypt_ciphertext_length,
aes_sha_256_cipher_encrypt,
aes_sha_256_cipher_decrypt_max_plaintext_length,
aes_sha_256_cipher_decrypt,
};
} // namespace
_olm_cipher *_olm_cipher_aes_sha_256_init(
struct _olm_cipher_aes_sha_256 *cipher,
uint8_t const * kdf_info,
size_t kdf_info_length
) {
cipher->base_cipher.ops = &aes_sha_256_cipher_ops;
cipher->kdf_info = kdf_info;
cipher->kdf_info_length = kdf_info_length;
return &(cipher->base_cipher);
}

23
src/olm.cpp
View file

@ -57,24 +57,13 @@ static std::uint8_t const * from_c(void const * bytes) {
return reinterpret_cast<std::uint8_t const *>(bytes);
}
static const std::uint8_t CIPHER_KDF_INFO[] = "Pickle";
const _olm_cipher *get_pickle_cipher() {
static _olm_cipher *cipher = NULL;
static _olm_cipher_aes_sha_256 PICKLE_CIPHER;
if (!cipher) {
cipher = _olm_cipher_aes_sha_256_init(
&PICKLE_CIPHER,
CIPHER_KDF_INFO, sizeof(CIPHER_KDF_INFO) - 1
);
}
return cipher;
}
static const struct _olm_cipher_aes_sha_256 PICKLE_CIPHER =
OLM_CIPHER_INIT_AES_SHA_256("Pickle");
std::size_t enc_output_length(
size_t raw_length
) {
auto *cipher = get_pickle_cipher();
auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
std::size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
length += cipher->ops->mac_length(cipher);
return olm::encode_base64_length(length);
@ -85,7 +74,7 @@ std::uint8_t * enc_output_pos(
std::uint8_t * output,
size_t raw_length
) {
auto *cipher = get_pickle_cipher();
auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
std::size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
length += cipher->ops->mac_length(cipher);
return output + olm::encode_base64_length(length) - length;
@ -95,7 +84,7 @@ std::size_t enc_output(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t * output, size_t raw_length
) {
auto *cipher = get_pickle_cipher();
auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
std::size_t ciphertext_length = cipher->ops->encrypt_ciphertext_length(
cipher, raw_length
);
@ -124,7 +113,7 @@ std::size_t enc_input(
return std::size_t(-1);
}
olm::decode_base64(input, b64_length, input);
auto *cipher = get_pickle_cipher();
auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
std::size_t raw_length = enc_length - cipher->ops->mac_length(cipher);
std::size_t result = cipher->ops->decrypt(
cipher,

15
src/session.cpp
View file

@ -35,22 +35,13 @@ static const olm::KdfInfo OLM_KDF_INFO = {
RATCHET_KDF_INFO, sizeof(RATCHET_KDF_INFO) - 1
};
const _olm_cipher *get_cipher() {
static _olm_cipher *cipher;
static _olm_cipher_aes_sha_256 OLM_CIPHER;
if (!cipher) {
cipher = _olm_cipher_aes_sha_256_init(
&OLM_CIPHER,
CIPHER_KDF_INFO, sizeof(CIPHER_KDF_INFO) - 1
);
}
return cipher;
}
static const struct _olm_cipher_aes_sha_256 OLM_CIPHER =
OLM_CIPHER_INIT_AES_SHA_256(CIPHER_KDF_INFO);
} // namespace
olm::Session::Session(
) : ratchet(OLM_KDF_INFO, get_cipher()),
) : ratchet(OLM_KDF_INFO, OLM_CIPHER_BASE(&OLM_CIPHER)),
last_error(OlmErrorCode::OLM_SUCCESS),
received_message(false) {

6
tests/test_ratchet.cpp
View file

@ -28,10 +28,8 @@ olm::KdfInfo kdf_info = {
ratchet_info, sizeof(ratchet_info) - 1
};
_olm_cipher_aes_sha_256 cipher0;
_olm_cipher *cipher = _olm_cipher_aes_sha_256_init(
&cipher0, message_info, sizeof(message_info) - 1
);
_olm_cipher_aes_sha_256 cipher0 = OLM_CIPHER_INIT_AES_SHA_256(message_info);
_olm_cipher *cipher = OLM_CIPHER_BASE(&cipher0);
std::uint8_t random_bytes[] = "0123456789ABDEF0123456789ABCDEF";
olm::Curve25519KeyPair alice_key;