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Diffstat (limited to 'src/outbound_group_session.c')
-rw-r--r--src/outbound_group_session.c65
1 files changed, 43 insertions, 22 deletions
diff --git a/src/outbound_group_session.c b/src/outbound_group_session.c
index 9f36ad8..9b2298a 100644
--- a/src/outbound_group_session.c
+++ b/src/outbound_group_session.c
@@ -199,51 +199,41 @@ size_t olm_group_encrypt_message_length(
return _olm_encode_base64_length(message_length);
}
-
-size_t olm_group_encrypt(
- OlmOutboundGroupSession *session,
- uint8_t const * plaintext, size_t plaintext_length,
- uint8_t * message, size_t max_message_length
+/** write an un-base64-ed message to the buffer */
+static size_t _encrypt(
+ OlmOutboundGroupSession *session, uint8_t const * plaintext, size_t plaintext_length,
+ uint8_t * buffer
) {
- size_t ciphertext_length;
- size_t rawmsglen;
+ size_t ciphertext_length, mac_length, message_length;
size_t result;
- uint8_t *ciphertext_ptr, *message_pos;
-
- rawmsglen = raw_message_length(session, plaintext_length);
-
- if (max_message_length < _olm_encode_base64_length(rawmsglen)) {
- session->last_error = OLM_OUTPUT_BUFFER_TOO_SMALL;
- return (size_t)-1;
- }
+ uint8_t *ciphertext_ptr;
ciphertext_length = megolm_cipher->ops->encrypt_ciphertext_length(
megolm_cipher,
plaintext_length
);
- /* we construct the message at the end of the buffer, so that
- * we have room to base64-encode it once we're done.
- */
- message_pos = message + _olm_encode_base64_length(rawmsglen) - rawmsglen;
+ mac_length = megolm_cipher->ops->mac_length(megolm_cipher);
/* first we build the message structure, then we encrypt
* the plaintext into it.
*/
- _olm_encode_group_message(
+ message_length = _olm_encode_group_message(
OLM_PROTOCOL_VERSION,
session->session_id, GROUP_SESSION_ID_LENGTH,
session->ratchet.counter,
ciphertext_length,
- message_pos,
+ buffer,
&ciphertext_ptr);
+ message_length += mac_length;
+
result = megolm_cipher->ops->encrypt(
megolm_cipher,
megolm_get_data(&(session->ratchet)), MEGOLM_RATCHET_LENGTH,
plaintext, plaintext_length,
ciphertext_ptr, ciphertext_length,
- message_pos, rawmsglen
+ buffer, message_length
);
if (result == (size_t)-1) {
@@ -252,6 +242,37 @@ size_t olm_group_encrypt(
megolm_advance(&(session->ratchet));
+ return result;
+}
+
+size_t olm_group_encrypt(
+ OlmOutboundGroupSession *session,
+ uint8_t const * plaintext, size_t plaintext_length,
+ uint8_t * message, size_t max_message_length
+) {
+ size_t rawmsglen;
+ size_t result;
+ uint8_t *message_pos;
+
+ rawmsglen = raw_message_length(session, plaintext_length);
+
+ if (max_message_length < _olm_encode_base64_length(rawmsglen)) {
+ session->last_error = OLM_OUTPUT_BUFFER_TOO_SMALL;
+ return (size_t)-1;
+ }
+
+ /* we construct the message at the end of the buffer, so that
+ * we have room to base64-encode it once we're done.
+ */
+ message_pos = message + _olm_encode_base64_length(rawmsglen) - rawmsglen;
+
+ /* write the message, and encrypt it, at message_pos */
+ result = _encrypt(session, plaintext, plaintext_length, message_pos);
+ if (result == (size_t)-1) {
+ return result;
+ }
+
+ /* bas64-encode it */
return _olm_encode_base64(
message_pos, rawmsglen, message
);