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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.
//! Secret Storage Support
//!
//! This submodule provides essential functionality for secret storage in
//! compliance with the [Matrix protocol specification][spec].
//!
//! Secret storage is a critical component that provides an encrypted
//! key/value storage system. It leverages [account data] events stored on the
//! Matrix homeserver to ensure secure and private storage of sensitive
//! information.
//!
//! For detailed information and usage guidelines, refer to the documentation of
//! the [`SecretStore`] struct.
//!
//! # Examples
//!
//! ```no_run
//! # use matrix_sdk::Client;
//! # use url::Url;
//! # async {
//! # let homeserver = Url::parse("http://example.com")?;
//! # let client = Client::new(homeserver).await?;
//! use ruma::events::secret::request::SecretName;
//!
//! // Open the store.
//! let secret_store = client
//! .encryption()
//! .secret_storage()
//! .open_secret_store("It's a secret to everybody")
//! .await?;
//!
//! // Import the secrets.
//! secret_store.import_secrets().await?;
//!
//! // Our own device should now be verified.
//! let device = client
//! .encryption()
//! .get_own_device()
//! .await?
//! .expect("We should be able to retrieve our own device");
//!
//! assert!(device.is_cross_signed_by_owner());
//!
//! # anyhow::Ok(()) };
//! ```
//!
//! [spec]: https://spec.matrix.org/v1.8/client-server-api/#secret-storage
//! [account data]: https://spec.matrix.org/v1.8/client-server-api/#client-config
use std::string::FromUtf8Error;
use matrix_sdk_base::crypto::{
secret_storage::{DecodeError, MacError, SecretStorageKey},
CryptoStoreError, SecretImportError,
};
use ruma::events::{
secret_storage::{
default_key::SecretStorageDefaultKeyEventContent, key::SecretStorageKeyEventContent,
},
EventContentFromType, GlobalAccountDataEventType,
};
use serde_json::value::to_raw_value;
use thiserror::Error;
use super::identities::ManualVerifyError;
use crate::Client;
mod futures;
mod secret_store;
pub use futures::CreateStore;
pub use secret_store::SecretStore;
/// Convenicence type alias for the secret-storage specific results.
pub type Result<T, E = SecretStorageError> = std::result::Result<T, E>;
/// Error type for the secret-storage subsystem.
#[derive(Debug, Error)]
pub enum SecretStorageError {
/// A typical SDK error.
#[error(transparent)]
Sdk(#[from] crate::Error),
/// Error when deserializing account data events.
#[error(transparent)]
Json(#[from] serde_json::Error),
/// The secret storage key could not have been decoded or verified
/// successfully.
#[error(transparent)]
SecretStorageKey(#[from] DecodeError),
/// The secret store could not be opened because info about the
/// secret-storage key could not have been found in the account data of
/// the user.
#[error(
"The info about the secret key could not have been found in the account data of the user"
)]
MissingKeyInfo {
/// The key ID of the default key. Will be set to the key ID in the
/// `m.secret_storage.default_key` event. If the
/// `m.secret_storage.default_key` does not exits, will be
/// `None`.
key_id: Option<String>,
},
/// A secret could not have been imported from the secret store into the
/// local store.
#[error(transparent)]
SecretImportError(#[from] SecretImportError),
/// A general storage error.
#[error(transparent)]
Storage(#[from] CryptoStoreError),
/// An error happened while trying to mark our own device as verified after
/// the private cross-signing keys have been imported.
#[error(transparent)]
Verification(#[from] ManualVerifyError),
/// Error describing a decryption failure of a secret.
#[error(transparent)]
Decryption(#[from] DecryptionError),
}
/// Error type describing decryption failures of the secret-storage system.
#[derive(Debug, Error)]
pub enum DecryptionError {
/// The secret could not have been decrypted.
#[error("Could not decrypt the secret using the secret storage key, invalid MAC.")]
Mac(#[from] MacError),
/// Could not decode the secret, the secret is not valid UTF-8.
#[error("Could not decode the secret, the secret is not valid UTF-8")]
Utf8(#[from] FromUtf8Error),
}
/// A high-level API to manage secret storage.
///
/// To get this, use [`Client::encryption()::secret_storage()`].
#[derive(Debug)]
pub struct SecretStorage {
pub(super) client: Client,
}
impl SecretStorage {
/// Open the [`SecretStore`] with the given `key`.
///
/// The `secret_storage_key` can be a passphrase or a Base58 encoded secret
/// storage key.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::Client;
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// use ruma::events::secret::request::SecretName;
///
/// let secret_store = client
/// .encryption()
/// .secret_storage()
/// .open_secret_store("It's a secret to everybody")
/// .await?;
///
/// let my_secret = "Top secret secret";
/// let my_secret_name = "m.treasure";
///
/// secret_store.put_secret(my_secret_name, my_secret);
///
/// # anyhow::Ok(()) };
/// ```
pub async fn open_secret_store(&self, secret_storage_key: &str) -> Result<SecretStore> {
let maybe_default_key_id = self
.client
.account()
.fetch_account_data(GlobalAccountDataEventType::SecretStorageDefaultKey)
.await?;
if let Some(default_key_id) = maybe_default_key_id {
let default_key_id =
default_key_id.deserialize_as::<SecretStorageDefaultKeyEventContent>()?;
let event_type =
GlobalAccountDataEventType::SecretStorageKey(default_key_id.key_id.to_owned());
let secret_key =
self.client.account().fetch_account_data(event_type.to_owned()).await?;
if let Some(secret_key_content) = secret_key {
let event_type = event_type.to_string();
let secret_key_content = to_raw_value(&secret_key_content)?;
let secret_key_content =
SecretStorageKeyEventContent::from_parts(&event_type, &secret_key_content)?;
let key =
SecretStorageKey::from_account_data(secret_storage_key, secret_key_content)?;
Ok(SecretStore { client: self.client.to_owned(), key })
} else {
Err(SecretStorageError::MissingKeyInfo { key_id: Some(default_key_id.key_id) })
}
} else {
Err(SecretStorageError::MissingKeyInfo { key_id: None })
}
}
/// Create a new [`SecretStore`].
///
/// The [`SecretStore`] will be protected by a randomly generated key, or
/// optionally a passphrase can be provided as well.
///
/// In both cases, whether a passphrase was provided or not, the key to open
/// the [`SecretStore`] can be obtained using the
/// [`SecretStore::secret_storage_key()`] method.
///
/// *Note*: This method will set the new secret storage key as the default
/// key in the `m.secret_storage.default_key` event. All the known secrets
/// will be re-encrypted and uploaded to the homeserver as well. This
/// includes the following secrets:
///
/// - `m.cross_signing.master`: The master cross-signing key.
/// - `m.cross_signing.self_signing`: The self-signing cross-signing key.
/// - `m.cross_signing.user_signing`: The user-signing cross-signing key.
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk::Client;
/// # use url::Url;
/// # async {
/// # let homeserver = Url::parse("http://example.com")?;
/// # let client = Client::new(homeserver).await?;
/// use ruma::events::secret::request::SecretName;
///
/// let secret_store = client
/// .encryption()
/// .secret_storage()
/// .create_secret_store()
/// .await?;
///
/// let my_secret = "Top secret secret";
/// let my_secret_name = SecretName::from("m.treasure");
///
/// secret_store.put_secret(my_secret_name, my_secret);
///
/// let secret_storage_key = secret_store.secret_storage_key();
///
/// println!("Your secret storage key is {secret_storage_key}, save it somewhere safe.");
///
/// # anyhow::Ok(()) };
/// ```
pub fn create_secret_store(&self) -> CreateStore<'_> {
CreateStore { secret_storage: self, passphrase: None }
}
/// Run a network request to find if secret storage is set up for this user.
pub async fn is_enabled(&self) -> crate::Result<bool> {
if let Some(content) = self
.client
.account()
.fetch_account_data(GlobalAccountDataEventType::SecretStorageDefaultKey)
.await?
{
// Since we can't delete account data events, we're going to treat
// deserialization failures as secret storage being disabled.
Ok(content.deserialize_as::<SecretStorageDefaultKeyEventContent>().is_ok())
} else {
// No account data event found, must be disabled.
Ok(false)
}
}
}