Commit a919a149 authored by Richard van der Hoff's avatar Richard van der Hoff
Browse files

Update megolm_cipher as a global struct

Initialise megolm_cipher via the preprocessor macro, instead of with a
function.
parent fa1e9446
......@@ -49,11 +49,11 @@ typedef struct Megolm {
/**
* Get the cipher used in megolm-backed conversations
* The cipher used in megolm-backed conversations
*
* (AES256 + SHA256, with keys based on an HKDF with info of MEGOLM_KEYS)
*/
const struct _olm_cipher *megolm_cipher();
extern const struct _olm_cipher *megolm_cipher;
/**
* initialize the megolm ratchet. random_data should be at least
......
......@@ -168,7 +168,6 @@ size_t olm_group_decrypt_max_plaintext_length(
uint8_t * message, size_t message_length
) {
size_t r;
const struct _olm_cipher *cipher = megolm_cipher();
struct _OlmDecodeGroupMessageResults decoded_results;
r = _olm_decode_base64(message, message_length, message);
......@@ -179,7 +178,7 @@ size_t olm_group_decrypt_max_plaintext_length(
_olm_decode_group_message(
message, message_length,
cipher->ops->mac_length(cipher),
megolm_cipher->ops->mac_length(megolm_cipher),
&decoded_results);
if (decoded_results.version != OLM_PROTOCOL_VERSION) {
......@@ -192,8 +191,8 @@ size_t olm_group_decrypt_max_plaintext_length(
return (size_t)-1;
}
return cipher->ops->decrypt_max_plaintext_length(
cipher, decoded_results.ciphertext_length);
return megolm_cipher->ops->decrypt_max_plaintext_length(
megolm_cipher, decoded_results.ciphertext_length);
}
......@@ -203,7 +202,6 @@ size_t olm_group_decrypt(
uint8_t * plaintext, size_t max_plaintext_length
) {
struct _OlmDecodeGroupMessageResults decoded_results;
const struct _olm_cipher *cipher = megolm_cipher();
size_t max_length, raw_message_length, r;
Megolm *megolm;
Megolm tmp_megolm;
......@@ -216,7 +214,7 @@ size_t olm_group_decrypt(
_olm_decode_group_message(
message, raw_message_length,
cipher->ops->mac_length(cipher),
megolm_cipher->ops->mac_length(megolm_cipher),
&decoded_results);
if (decoded_results.version != OLM_PROTOCOL_VERSION) {
......@@ -231,8 +229,8 @@ size_t olm_group_decrypt(
return (size_t)-1;
}
max_length = cipher->ops->decrypt_max_plaintext_length(
cipher,
max_length = megolm_cipher->ops->decrypt_max_plaintext_length(
megolm_cipher,
decoded_results.ciphertext_length
);
if (max_plaintext_length < max_length) {
......@@ -258,8 +256,8 @@ size_t olm_group_decrypt(
megolm_advance_to(megolm, decoded_results.message_index);
/* now try checking the mac, and decrypting */
r = cipher->ops->decrypt(
cipher,
r = megolm_cipher->ops->decrypt(
megolm_cipher,
megolm_get_data(megolm), MEGOLM_RATCHET_LENGTH,
message, raw_message_length,
decoded_results.ciphertext, decoded_results.ciphertext_length,
......
......@@ -22,18 +22,9 @@
#include "olm/crypto.h"
#include "olm/pickle.h"
const struct _olm_cipher *megolm_cipher() {
static const uint8_t CIPHER_KDF_INFO[] = "MEGOLM_KEYS";
static struct _olm_cipher *cipher;
static struct _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 MEGOLM_CIPHER =
OLM_CIPHER_INIT_AES_SHA_256("MEGOLM_KEYS");
const struct _olm_cipher *megolm_cipher = OLM_CIPHER_BASE(&MEGOLM_CIPHER);
/* the seeds used in the HMAC-SHA-256 functions for each part of the ratchet.
*/
......
......@@ -179,13 +179,12 @@ static size_t raw_message_length(
size_t plaintext_length)
{
size_t ciphertext_length, mac_length;
const struct _olm_cipher *cipher = megolm_cipher();
ciphertext_length = cipher->ops->encrypt_ciphertext_length(
cipher, plaintext_length
ciphertext_length = megolm_cipher->ops->encrypt_ciphertext_length(
megolm_cipher, plaintext_length
);
mac_length = cipher->ops->mac_length(cipher);
mac_length = megolm_cipher->ops->mac_length(megolm_cipher);
return _olm_encode_group_message_length(
GROUP_SESSION_ID_LENGTH, session->ratchet.counter,
......@@ -210,7 +209,6 @@ size_t olm_group_encrypt(
size_t rawmsglen;
size_t result;
uint8_t *ciphertext_ptr, *message_pos;
const struct _olm_cipher *cipher = megolm_cipher();
rawmsglen = raw_message_length(session, plaintext_length);
......@@ -219,8 +217,8 @@ size_t olm_group_encrypt(
return (size_t)-1;
}
ciphertext_length = cipher->ops->encrypt_ciphertext_length(
cipher,
ciphertext_length = megolm_cipher->ops->encrypt_ciphertext_length(
megolm_cipher,
plaintext_length
);
......@@ -240,8 +238,8 @@ size_t olm_group_encrypt(
message_pos,
&ciphertext_ptr);
result = cipher->ops->encrypt(
cipher,
result = megolm_cipher->ops->encrypt(
megolm_cipher,
megolm_get_data(&(session->ratchet)), MEGOLM_RATCHET_LENGTH,
plaintext, plaintext_length,
ciphertext_ptr, ciphertext_length,
......
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