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// Copyright 2023 The Matrix.org Foundation C.I.C.
//
// 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.
//! The recovery module
//!
//! The recovery module attempts to provide a unified and simplified view over
//! the secret storage and backup subsystems.
//!
//! **Note**: If you are using this module, do not use the [`SecretStorage`] and
//! [`Backups`] subsystems directly. This module makes assumptions that might be
//! broken by the direct usage of the respective lower level modules.
//!
//! **Note**: The term Recovery used in this submodule is not the same as the
//! [`Recovery key`] mentioned in the spec. The recovery key from the spec is
//! solely about backups, while the term recovery in this file includes both the
//! backups and the secret storage subsystems. The recovery key mentioned in
//! this file is the secret storage key.
//!
//! You should configure your client to bootstrap cross-signing automatically
//! and may choose to let your client automatically create a backup, if it
//! doesn't exist, as well:
//!
//! ```no_run
//! use matrix_sdk::{encryption::EncryptionSettings, Client};
//!
//! # async {
//! # let homeserver = "http://example.org";
//! let client = Client::builder()
//! .homeserver_url(homeserver)
//! .with_encryption_settings(EncryptionSettings {
//! auto_enable_cross_signing: true,
//! auto_enable_backups: true,
//! ..Default::default()
//! })
//! .build()
//! .await?;
//! # anyhow::Ok(()) };
//! ```
//!
//! # Examples
//!
//! For a newly registered user you will want to enable recovery, either
//! immediately or before the user logs out.
//!
//! ```no_run
//! # use matrix_sdk::{Client, encryption::recovery::EnableProgress};
//! # use url::Url;
//! # async {
//! # let homeserver = Url::parse("http://example.com")?;
//! # let client = Client::new(homeserver).await?;
//! let recovery = client.encryption().recovery();
//!
//! // Create a new recovery key, you can use the provided passphrase, or the returned recovery key
//! // to recover.
//! let recovery_key = recovery
//! .enable()
//! .wait_for_backups_to_upload()
//! .with_passphrase("my passphrase")
//! .await;
//! # anyhow::Ok(()) };
//! ```
//!
//! If the user logs in with another device, you'll want to let the user recover
//! its secrets by entering the recovery key or recovery passphrase.
//!
//! ```no_run
//! # use matrix_sdk::{Client, encryption::recovery::EnableProgress};
//! # use url::Url;
//! # async {
//! # let homeserver = Url::parse("http://example.com")?;
//! # let client = Client::new(homeserver).await?;
//! let recovery = client.encryption().recovery();
//!
//! // Create a new recovery key, you can use the provided passphrase, or the returned recovery key
//! // to recover.
//! recovery.recover("my recovery key or passphrase").await;
//! # anyhow::Ok(()) };
//! ```
//!
//! [`Recovery key`]: https://spec.matrix.org/v1.8/client-server-api/#recovery-key
use futures_core::{Future, Stream};
use futures_util::StreamExt as _;
use ruma::{
api::client::keys::get_keys,
events::{
secret::send::ToDeviceSecretSendEvent,
secret_storage::default_key::SecretStorageDefaultKeyEvent,
},
};
use tracing::{error, info, instrument, warn};
#[cfg(doc)]
use crate::encryption::{
backups::Backups,
secret_storage::{SecretStorage, SecretStore},
};
use crate::{client::WeakClient, encryption::backups::BackupState, Client};
pub mod futures;
mod types;
pub use self::types::{EnableProgress, RecoveryError, RecoveryState, Result};
use self::{
futures::{Enable, RecoverAndReset, Reset},
types::{BackupDisabledContent, SecretStorageDisabledContent},
};
use crate::encryption::{AuthData, CrossSigningResetAuthType, CrossSigningResetHandle};
/// The recovery manager for the [`Client`].
#[derive(Debug)]
pub struct Recovery {
pub(super) client: Client,
}
impl Recovery {
/// Get the current [`RecoveryState`] for this [`Client`].
pub fn state(&self) -> RecoveryState {
self.client.inner.e2ee.recovery_state.get()
}
/// Get a stream of updates to the [`RecoveryState`].
///
/// This method will send out the current state as the first update.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::RecoveryState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// use futures_util::StreamExt;
///
/// let recovery = client.encryption().recovery();
///
/// let mut state_stream = recovery.state_stream();
///
/// while let Some(update) = state_stream.next().await {
/// match update {
/// RecoveryState::Enabled => {
/// println!("Recovery has been enabled");
/// }
/// _ => (),
/// }
/// }
/// # anyhow::Ok(()) };
/// ```
pub fn state_stream(&self) -> impl Stream<Item = RecoveryState> {
self.client.inner.e2ee.recovery_state.subscribe_reset()
}
/// Enable secret storage *and* backups.
///
/// This method will create a new secret storage key and a new backup if one
/// doesn't already exist. It will then upload all the locally cached
/// secrets, including the backup recovery key, to the new secret store.
///
/// This method will throw an error if a backup already exists on the
/// homeserver but this [`Client`] isn't connected to the existing backup.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::EnableProgress};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// use futures_util::StreamExt;
///
/// let recovery = client.encryption().recovery();
///
/// let enable = recovery
/// .enable()
/// .wait_for_backups_to_upload()
/// .with_passphrase("my passphrase");
///
/// let mut progress_stream = enable.subscribe_to_progress();
///
/// tokio::spawn(async move {
/// while let Some(update) = progress_stream.next().await {
/// let Ok(update) = update else {
/// panic!("Update to the enable progress lagged")
/// };
///
/// match update {
/// EnableProgress::CreatingBackup => {
/// println!("Creating a new backup");
/// }
/// EnableProgress::CreatingRecoveryKey => {
/// println!("Creating a new recovery key");
/// }
/// EnableProgress::Done { .. } => {
/// println!("Recovery has been enabled");
/// break;
/// }
/// _ => (),
/// }
/// }
/// });
///
/// let recovery_key = enable.await?;
///
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub fn enable(&self) -> Enable<'_> {
Enable::new(self)
}
/// Create a new backup if one does not exist yet.
///
/// This method will throw an error if a backup already exists on the
/// homeserver but this [`Client`] isn't connected to the existing backup.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::backups::BackupState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// let recovery = client.encryption().recovery();
///
/// recovery.enable_backup().await?;
///
/// assert_eq!(client.encryption().backups().state(), BackupState::Enabled);
///
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub async fn enable_backup(&self) -> Result<()> {
if !self.client.encryption().backups().exists_on_server().await? {
self.mark_backup_as_enabled().await?;
self.client.encryption().backups().create().await?;
self.client.encryption().backups().maybe_trigger_backup();
Ok(())
} else {
Err(RecoveryError::BackupExistsOnServer)
}
}
/// Disable recovery completely.
///
/// This method will do the following steps:
///
/// 1. Disable the uploading of room keys to a currently active backup.
/// 2. Delete the currently active backup.
/// 3. Set the `m.secret_storage.default_key` global account data event to
/// an empty JSON content.
/// 4. Set a global account data event so clients won't attempt to
/// automatically re-enable a backup.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::RecoveryState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// let recovery = client.encryption().recovery();
///
/// recovery.disable().await?;
///
/// assert_eq!(recovery.state(), RecoveryState::Disabled);
///
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub async fn disable(&self) -> Result<()> {
self.client.encryption().backups().disable().await?;
// Why oh why, can't we delete account data events?
self.client.account().set_account_data(SecretStorageDisabledContent {}).await?;
self.client.account().set_account_data(BackupDisabledContent { disabled: true }).await?;
self.update_recovery_state().await?;
// TODO: Do we want to "delete" the known secrets as well?
Ok(())
}
/// Reset the recovery key.
///
/// This will rotate the secret storage key and re-upload all the secrets to
/// the [`SecretStore`].
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::RecoveryState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// let recovery = client.encryption().recovery();
///
/// let new_recovery_key =
/// recovery.reset_key().with_passphrase("my passphrase").await;
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub fn reset_key(&self) -> Reset<'_> {
// TODO: Should this only be possible if we're in the RecoveryState::Enabled
// state? Otherwise we'll create a new secret store but won't be able to
// upload all the secrets.
Reset::new(self)
}
/// Reset the recovery key but first import all the secrets from secret
/// storage.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::RecoveryState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// let recovery = client.encryption().recovery();
///
/// let new_recovery_key = recovery
/// .recover_and_reset("my old passphrase or key")
/// .with_passphrase("my new passphrase")
/// .await?;
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub fn recover_and_reset<'a>(&'a self, old_key: &'a str) -> RecoverAndReset<'_> {
RecoverAndReset::new(self, old_key)
}
/// Completely reset the current user's crypto identity.
/// This method will go through the following steps:
///
/// 1. Disable backing up room keys and delete the active backup
/// 2. Disable recovery and delete secret storage
/// 3. Go through the cross-signing key reset flow
/// 4. Finally, re-enable key backups (only if they were already enabled)
///
/// Disclaimer: failures in this flow will potentially leave the user in
/// an inconsistent state but they're expected to just run the reset flow
/// again as presumably the reason they started it to begin with was
/// that they no longer had access to any of their data.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{
/// encryption::recovery, encryption::CrossSigningResetAuthType, ruma::api::client::uiaa,
/// Client,
/// };
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// # let user_id = unimplemented!();
/// let encryption = client.encryption();
///
/// if let Some(handle) = encryption.recovery().reset_identity().await? {
/// match handle.auth_type() {
/// CrossSigningResetAuthType::Uiaa(uiaa) => {
/// let password = "1234".to_owned();
/// let mut password = uiaa::Password::new(user_id, password);
/// password.session = uiaa.session;
///
/// handle.reset(Some(uiaa::AuthData::Password(password))).await?;
/// }
/// CrossSigningResetAuthType::Oidc(o) => {
/// println!(
/// "To reset your end-to-end encryption cross-signing identity, \
/// you first need to approve it at {}",
/// o.approval_url
/// );
/// handle.reset(None).await?;
/// }
/// }
/// }
/// # anyhow::Ok(()) };
/// ```
pub async fn reset_identity(&self) -> Result<Option<IdentityResetHandle>> {
self.client.encryption().backups().disable_and_delete().await?; // 1.
// 2. (We can't delete account data events)
self.client.account().set_account_data(SecretStorageDisabledContent {}).await?;
self.client.encryption().recovery().update_recovery_state().await?;
let cross_signing_reset_handle = self.client.encryption().reset_cross_signing().await?;
if let Some(handle) = cross_signing_reset_handle {
// Authentication required, backups will be re-enabled after the reset
Ok(Some(IdentityResetHandle {
client: self.client.clone(),
cross_signing_reset_handle: handle,
}))
} else {
// No authentication required, re-enable backups
if self.client.encryption().recovery().should_auto_enable_backups().await? {
self.client.encryption().recovery().enable_backup().await?; // 4.
}
Ok(None)
}
}
/// Recover all the secrets from the homeserver.
///
/// This method is a convenience method around the
/// [`SecretStore::import_secrets()`] method, please read the documentation
/// of this method for more information about what happens if you call
/// this method.
///
/// In short, this method will turn a newly created [`Client`] into a fully
/// end-to-end encryption enabled client.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::{Client, encryption::recovery::RecoveryState};
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// let recovery = client.encryption().recovery();
///
/// recovery.recover("my recovery key or passphrase").await;
///
/// assert_eq!(recovery.state(), RecoveryState::Enabled);
/// # anyhow::Ok(()) };
/// ```
#[instrument(skip_all)]
pub async fn recover(&self, recovery_key: &str) -> Result<()> {
let store =
self.client.encryption().secret_storage().open_secret_store(recovery_key).await?;
store.import_secrets().await?;
self.update_recovery_state().await?;
Ok(())
}
/// Is this device the last device the user has?
///
/// This method is useful to check if we should recommend to the user that
/// they should enable recovery, typically done before logging out.
///
/// If the user does not enable recovery before logging out of their last
/// device, they will not be able to decrypt historic messages once they
/// create a new device.
pub async fn are_we_the_last_man_standing(&self) -> Result<bool> {
let olm_machine = self.client.olm_machine().await;
let olm_machine = olm_machine.as_ref().ok_or(crate::Error::NoOlmMachine)?;
let user_id = olm_machine.user_id();
self.client.encryption().ensure_initial_key_query().await?;
let devices = self.client.encryption().get_user_devices(user_id).await?;
Ok(devices.devices().count() == 1)
}
/// Did we correctly set up cross-signing and backups?
async fn all_known_secrets_available(&self) -> Result<bool> {
// Cross-signing state is fine if we have all the private cross-signing keys, as
// indicated in the status.
let cross_signing_complete = self
.client
.encryption()
.cross_signing_status()
.await
.map(|status| status.is_complete());
if !cross_signing_complete.unwrap_or_default() {
return Ok(false);
}
// The backup state is fine if we have backups enabled locally, or if backups
// have been marked as disabled.
if self.client.encryption().backups().are_enabled().await {
Ok(true)
} else {
self.are_backups_marked_as_disabled().await
}
}
async fn should_auto_enable_backups(&self) -> Result<bool> {
// If we didn't already enable backups, we don't see a backup version on the
// server, and finally if backups have not been marked to be explicitly
// disabled, then we can automatically enable them.
Ok(self.client.inner.e2ee.encryption_settings.auto_enable_backups
&& !self.client.encryption().backups().are_enabled().await
&& !self.client.encryption().backups().exists_on_server().await?
&& !self.are_backups_marked_as_disabled().await?)
}
pub(crate) async fn setup(&self) -> Result<()> {
info!("Setting up account data listeners and trying to setup recovery");
self.client.add_event_handler(Self::default_key_event_handler);
self.client.add_event_handler(Self::secret_send_event_handler);
self.client.inner.e2ee.initialize_recovery_state_update_task(&self.client);
self.update_recovery_state().await?;
if self.should_auto_enable_backups().await? {
info!("Trying to automatically enable backups");
if let Err(e) = self.enable_backup().await {
warn!("Could not automatically enable backups: {e:?}");
}
}
Ok(())
}
/// Run a network request to figure whether backups have been disabled at
/// the account level.
async fn are_backups_marked_as_disabled(&self) -> Result<bool> {
Ok(self
.client
.account()
.fetch_account_data(BackupDisabledContent::event_type())
.await?
.map(|event| {
event
.deserialize_as::<BackupDisabledContent>()
.map(|event| event.disabled)
.unwrap_or(false)
})
.unwrap_or(false))
}
async fn mark_backup_as_enabled(&self) -> Result<()> {
self.client.account().set_account_data(BackupDisabledContent { disabled: false }).await?;
Ok(())
}
async fn check_recovery_state(&self) -> Result<RecoveryState> {
Ok(if self.client.encryption().secret_storage().is_enabled().await? {
if self.all_known_secrets_available().await? {
RecoveryState::Enabled
} else {
RecoveryState::Incomplete
}
} else {
RecoveryState::Disabled
})
}
async fn update_recovery_state(&self) -> Result<()> {
let new_state = self.check_recovery_state().await?;
let old_state = self.client.inner.e2ee.recovery_state.set(new_state);
if new_state != old_state {
info!("Recovery state changed from {old_state:?} to {new_state:?}");
}
Ok(())
}
async fn update_recovery_state_no_fail(&self) {
if let Err(e) = self.update_recovery_state().await {
error!("Couldn't update the recovery state: {e:?}");
}
}
#[instrument]
async fn secret_send_event_handler(_: ToDeviceSecretSendEvent, client: Client) {
client.encryption().recovery().update_recovery_state_no_fail().await;
}
#[instrument]
async fn default_key_event_handler(_: SecretStorageDefaultKeyEvent, client: Client) {
client.encryption().recovery().update_recovery_state_no_fail().await;
}
/// Listen for changes in the [`BackupState`] and, if necessary, update the
/// [`RecoveryState`] accordingly.
///
/// This should not be called directly, this method is put into a background
/// task which is always listening for updates in the [`BackupState`].
pub(crate) fn update_state_after_backup_state_change(
client: &Client,
) -> impl Future<Output = ()> {
let mut stream = client.encryption().backups().state_stream();
let weak = WeakClient::from_client(client);
async move {
while let Some(update) = stream.next().await {
if let Some(client) = weak.get() {
match update {
Ok(update) => {
// The recovery state only cares about these two states, the
// intermediate states that tell us that
// we're creating a backup are not interesting.
if matches!(update, BackupState::Unknown | BackupState::Enabled) {
client
.encryption()
.recovery()
.update_recovery_state_no_fail()
.await;
}
}
Err(_) => {
// We missed some updates, let's update our state in case something
// changed.
client.encryption().recovery().update_recovery_state_no_fail().await;
}
}
} else {
break;
}
}
}
}
#[instrument(skip_all)]
pub(crate) async fn update_state_after_keys_query(&self, response: &get_keys::v3::Response) {
if let Some(user_id) = self.client.user_id() {
if response.master_keys.contains_key(user_id) {
// TODO: This is unnecessarily expensive, we could let the crypto crate notify
// us that our private keys got erased... But, the OlmMachine
// gets recreated and... You know the drill by now...
self.update_recovery_state_no_fail().await;
}
}
}
}
/// A helper struct that handles continues resetting a user's crypto identity
/// after authentication was required and re-enabling backups (if necessary) at
/// the end of it
#[derive(Debug)]
pub struct IdentityResetHandle {
client: Client,
cross_signing_reset_handle: CrossSigningResetHandle,
}
impl IdentityResetHandle {
/// Get the underlying [`CrossSigningResetAuthType`] this identity reset
/// process is using.
pub fn auth_type(&self) -> &CrossSigningResetAuthType {
&self.cross_signing_reset_handle.auth_type
}
/// This method will retry to upload the device keys after the previous try
/// failed due to required authentication
pub async fn reset(&self, auth: Option<AuthData>) -> Result<()> {
self.cross_signing_reset_handle.auth(auth).await?;
if self.client.encryption().recovery().should_auto_enable_backups().await? {
self.client.encryption().recovery().enable_backup().await?;
}
Ok(())
}
/// Cancel the ongoing identity reset process
pub async fn cancel(&self) {
self.cross_signing_reset_handle.cancel().await;
}
}