olm/src/pickle_encoding.c
Richard van der Hoff a7310c5821 Return the base64-encoded length of pickles
make olm_pickle_* return the lengths of the base64-encoded pickles, rather than
the raw pickle. (From the application's POV, the format of the pickle is
opaque: it doesn't even know that it is base64-encoded. So returning the length
of the raw pickle is particularly unhelpful.)
2016-10-24 10:06:06 +01:00

92 lines
3 KiB
C

/* 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 base64_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;
}