Commit 42a300fc authored by Richard van der Hoff's avatar Richard van der Hoff
Browse files

Factor out pickle_encoding from olm.cpp

We don't need to have all of the top-level pickling functions in olm.cpp;
factor out the utilities to support it to pickle_encoding.cpp (and make sure
that they have plain-C bindings).
parent 256bce10
/* Copyright 2016 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.
*/
/* functions for encrypting and decrypting pickled representations of objects */
#ifndef OLM_PICKLE_ENCODING_H_
#define OLM_PICKLE_ENCODING_H_
#include <stddef.h>
#include <stdint.h>
#include "olm/error.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* Get the number of bytes needed to encode a pickle of the length given
*/
size_t _olm_enc_output_length(size_t raw_length);
/**
* Get the point in the output buffer that the raw pickle should be written to.
*
* In order that we can use the same buffer for the raw pickle, and the encoded
* pickle, the raw pickle needs to be written at the end of the buffer. (The
* base-64 encoding would otherwise overwrite the end of the input before it
* was encoded.)
*/
uint8_t *_olm_enc_output_pos(uint8_t * output, size_t raw_length);
/**
* Encrypt and encode the given pickle in-situ.
*
* The raw pickle should have been written to enc_output_pos(pickle,
* raw_length).
*
* Returns the number of bytes in the encoded pickle.
*/
size_t _olm_enc_output(
uint8_t const * key, size_t key_length,
uint8_t *pickle, size_t raw_length
);
/**
* Decode and decrypt the given pickle in-situ.
*
* Returns the number of bytes in the decoded pickle, or olm_error() on error,
* in which case *last_error will be updated, if last_error is non-NULL.
*/
size_t _olm_enc_input(
uint8_t const * key, size_t key_length,
uint8_t * input, size_t b64_length,
enum OlmErrorCode * last_error
);
#ifdef __cplusplus
} // extern "C"
#endif
#endif /* OLM_PICKLE_ENCODING_H_ */
......@@ -16,6 +16,7 @@
#include "olm/session.hh"
#include "olm/account.hh"
#include "olm/cipher.h"
#include "olm/pickle_encoding.h"
#include "olm/utility.hh"
#include "olm/base64.hh"
#include "olm/memory.hh"
......@@ -57,78 +58,6 @@ static std::uint8_t const * from_c(void const * bytes) {
return reinterpret_cast<std::uint8_t const *>(bytes);
}
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 = 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);
}
std::uint8_t * enc_output_pos(
std::uint8_t * output,
size_t raw_length
) {
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;
}
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 = OLM_CIPHER_BASE(&PICKLE_CIPHER);
std::size_t ciphertext_length = cipher->ops->encrypt_ciphertext_length(
cipher, raw_length
);
std::size_t length = ciphertext_length + cipher->ops->mac_length(cipher);
std::size_t base64_length = olm::encode_base64_length(length);
std::uint8_t * raw_output = output + base64_length - length;
cipher->ops->encrypt(
cipher,
key, key_length,
raw_output, raw_length,
raw_output, ciphertext_length,
raw_output, length
);
olm::encode_base64(raw_output, length, output);
return raw_length;
}
std::size_t enc_input(
std::uint8_t const * key, std::size_t key_length,
std::uint8_t * input, size_t b64_length,
OlmErrorCode & last_error
) {
std::size_t enc_length = olm::decode_base64_length(b64_length);
if (enc_length == std::size_t(-1)) {
last_error = OlmErrorCode::OLM_INVALID_BASE64;
return std::size_t(-1);
}
olm::decode_base64(input, b64_length, input);
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,
key, key_length,
input, enc_length,
input, raw_length,
input, raw_length
);
if (result == std::size_t(-1)) {
last_error = OlmErrorCode::OLM_BAD_ACCOUNT_KEY;
}
return result;
}
std::size_t b64_output_length(
size_t raw_length
) {
......@@ -270,14 +199,14 @@ size_t olm_clear_utility(
size_t olm_pickle_account_length(
OlmAccount * account
) {
return enc_output_length(pickle_length(*from_c(account)));
return _olm_enc_output_length(pickle_length(*from_c(account)));
}
size_t olm_pickle_session_length(
OlmSession * session
) {
return enc_output_length(pickle_length(*from_c(session)));
return _olm_enc_output_length(pickle_length(*from_c(session)));
}
......@@ -288,12 +217,12 @@ size_t olm_pickle_account(
) {
olm::Account & object = *from_c(account);
std::size_t raw_length = pickle_length(object);
if (pickled_length < enc_output_length(raw_length)) {
if (pickled_length < _olm_enc_output_length(raw_length)) {
object.last_error = OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
pickle(enc_output_pos(from_c(pickled), raw_length), object);
return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
pickle(_olm_enc_output_pos(from_c(pickled), raw_length), object);
return _olm_enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}
......@@ -304,12 +233,12 @@ size_t olm_pickle_session(
) {
olm::Session & object = *from_c(session);
std::size_t raw_length = pickle_length(object);
if (pickled_length < enc_output_length(raw_length)) {
if (pickled_length < _olm_enc_output_length(raw_length)) {
object.last_error = OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
return size_t(-1);
}
pickle(enc_output_pos(from_c(pickled), raw_length), object);
return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
pickle(_olm_enc_output_pos(from_c(pickled), raw_length), object);
return _olm_enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}
......@@ -320,8 +249,8 @@ size_t olm_unpickle_account(
) {
olm::Account & object = *from_c(account);
std::uint8_t * const pos = from_c(pickled);
std::size_t raw_length = enc_input(
from_c(key), key_length, pos, pickled_length, object.last_error
std::size_t raw_length = _olm_enc_input(
from_c(key), key_length, pos, pickled_length, &object.last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
......@@ -348,8 +277,8 @@ size_t olm_unpickle_session(
) {
olm::Session & object = *from_c(session);
std::uint8_t * const pos = from_c(pickled);
std::size_t raw_length = enc_input(
from_c(key), key_length, pos, pickled_length, object.last_error
std::size_t raw_length = _olm_enc_input(
from_c(key), key_length, pos, pickled_length, &object.last_error
);
if (raw_length == std::size_t(-1)) {
return std::size_t(-1);
......
/* Copyright 2016 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.
*/
#include "olm/pickle_encoding.h"
#include "olm/base64.h"
#include "olm/cipher.h"
#include "olm/olm.h"
static const struct _olm_cipher_aes_sha_256 PICKLE_CIPHER =
OLM_CIPHER_INIT_AES_SHA_256("Pickle");
size_t _olm_enc_output_length(
size_t raw_length
) {
const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
length += cipher->ops->mac_length(cipher);
return _olm_encode_base64_length(length);
}
uint8_t * _olm_enc_output_pos(
uint8_t * output,
size_t raw_length
) {
const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
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;
}
size_t _olm_enc_output(
uint8_t const * key, size_t key_length,
uint8_t * output, size_t raw_length
) {
const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
size_t ciphertext_length = cipher->ops->encrypt_ciphertext_length(
cipher, raw_length
);
size_t length = ciphertext_length + cipher->ops->mac_length(cipher);
size_t base64_length = _olm_encode_base64_length(length);
uint8_t * raw_output = output + base64_length - length;
cipher->ops->encrypt(
cipher,
key, key_length,
raw_output, raw_length,
raw_output, ciphertext_length,
raw_output, length
);
_olm_encode_base64(raw_output, length, output);
return raw_length;
}
size_t _olm_enc_input(uint8_t const * key, size_t key_length,
uint8_t * input, size_t b64_length,
enum OlmErrorCode * last_error
) {
size_t enc_length = _olm_decode_base64_length(b64_length);
if (enc_length == (size_t)-1) {
if (last_error) {
*last_error = OLM_INVALID_BASE64;
}
return (size_t)-1;
}
_olm_decode_base64(input, b64_length, input);
const struct _olm_cipher *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
size_t raw_length = enc_length - cipher->ops->mac_length(cipher);
size_t result = cipher->ops->decrypt(
cipher,
key, key_length,
input, enc_length,
input, raw_length,
input, raw_length
);
if (result == (size_t)-1 && last_error) {
*last_error = OLM_BAD_ACCOUNT_KEY;
}
return result;
}
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