diff options
| -rw-r--r-- | matrix-e2e.c | 122 |
1 files changed, 121 insertions, 1 deletions
diff --git a/matrix-e2e.c b/matrix-e2e.c index fe820e2..665df21 100644 --- a/matrix-e2e.c +++ b/matrix-e2e.c @@ -712,6 +712,126 @@ void matrix_e2e_cleanup_connection(MatrixConnectionData *conn) /* * See: + * https://matrix.org/docs/guides/e2e_implementation.html#m-olm-v1-curve25519-aes-sha2 + * TODO: All the error paths in this function need to clean up! + */ +static void decrypt_olm(PurpleConnection *pc, MatrixConnectionData *conn, JsonObject *cevent, + JsonObject *cevent_content) +{ + const gchar *cevent_sender; + const gchar *sender_key; + JsonObject *cevent_ciphertext; + gchar *cevent_body_copy = NULL; + gchar *plaintext = NULL; + size_t max_plaintext_len = 0; + OlmSession *session = NULL; + cevent_sender = matrix_json_object_get_string_member(cevent, "sender"); + sender_key = matrix_json_object_get_string_member(cevent_content, + "sender_key"); + cevent_ciphertext = matrix_json_object_get_object_member(cevent_content, + "ciphertext"); + /* TODO: Look up sender_key - I think we need to check this against device + * list from user? */ + + if (!cevent_ciphertext || !sender_key) { + purple_debug_info("matrixprpl", + "%s: no ciphertext or sender_key in olm event\n", + __func__); + goto err; + } + JsonObject *our_ciphertext; + our_ciphertext = matrix_json_object_get_object_member(cevent_ciphertext, + conn->e2e->curve25519_pubkey); + if (!our_ciphertext) { + purple_debug_info("matrixprpl", + "%s: No ciphertext with our curve25519 pubkey\n", + __func__); + goto err; + } + JsonNode *type_node = matrix_json_object_get_member(our_ciphertext, "type"); + if (!type_node) { + purple_debug_info("matrixprpl", "%s: No type node\n", __func__); + goto err; + } + + gint64 type = matrix_json_node_get_int(type_node); + purple_debug_info("matrixprpl", + "%s: Type %zd olm encrypted message from %s\n", + __func__, (size_t)type, cevent_sender); + if (!type) { + /* A 'prekey' message to establish an Olm session + * TODO!!!!: Try existing sessions and check with + * matches_inbound_session */ + session = olm_session(g_malloc0(olm_session_size())); + const gchar *cevent_body; + cevent_body = matrix_json_object_get_string_member(our_ciphertext, + "body"); + gchar *cevent_body_copy = g_strdup(cevent_body); + if (olm_create_inbound_session_from(session, conn->e2e->oa, sender_key, + strlen(sender_key), + cevent_body_copy, strlen(cevent_body)) + == olm_error()) { + purple_debug_info("matrixprpl", + "%s: prekey inbound_session_from failed : %s\n", + __func__, olm_session_last_error(session)); + goto err; + } + if (olm_remove_one_time_keys(conn->e2e->oa, session) == olm_error()) { + purple_debug_info("matrixprpl", + "%s: Failed to remove 1tk, inbound session: %s\n", + __func__, olm_account_last_error(conn->e2e->oa)); + goto err; + } + cevent_body_copy = g_strdup(cevent_body); + max_plaintext_len = olm_decrypt_max_plaintext_length(session, + 0 /* Prekey */, + cevent_body_copy, + strlen(cevent_body_copy)); + if (max_plaintext_len == olm_error()) { + purple_debug_info("matrixprpl", + "%s: Failed to get plaintext length %s\n", + __func__, olm_session_last_error(session)); + goto err; + } + plaintext = g_malloc0(max_plaintext_len + 1); + cevent_body_copy = g_strdup(cevent_body); + + size_t pt_len = olm_decrypt(session, 0 /* Prekey */, cevent_body_copy, + strlen(cevent_body), + plaintext, max_plaintext_len); + if (pt_len == olm_error() || pt_len >= max_plaintext_len) { + purple_debug_info("matrixprpl", + "%s: Failed to decrypt inbound session creation" + " event: %s\n", + __func__, olm_session_last_error(session)); + goto err; + } + plaintext[pt_len] = '\0'; + // TODO: Store session in db + } else { + purple_debug_info("matrixprpl", "%s: Type %zd olm\n", __func__, type); + } + // TODO resave account? Or just session? + // + if (plaintext) { + clear_mem(plaintext, max_plaintext_len); + } + g_free(plaintext); + g_free(cevent_body_copy); + + return; + +err: + if (plaintext) { + clear_mem(plaintext, max_plaintext_len); + } + g_free(plaintext); + g_free(cevent_body_copy); + g_free(session); +} + +/* + * See: * https://matrix.org/docs/guides/e2e_implementation.html#handling-an-m-room-encrypted-event * For decrypting d2d messages * TODO: We really need to build a queue of stuff to decrypt, especially since they take multiple @@ -745,7 +865,7 @@ void matrix_e2e_decrypt_d2d(PurpleConnection *pc, JsonObject *cevent) } if (!strcmp(cevent_algo, "m.olm.v1.curve25519-aes-sha2")) { - // TODO: call decrypt_olm(pc, conn, cevent, cevent_content); + decrypt_olm(pc, conn, cevent, cevent_content); } else if (!strcmp(cevent_algo, "m.megolm.v1.aes-sha2")) { purple_debug_info("matrixprpl", "%s: It's megolm - unexpected for d2d!\n", __func__); |