crypto: Move the olm encryption logic into the Session struct.

matrix_sdk_crypto/src/machine.rs

@@ -32,13 +32,10 @@ use super::{device::Device, store::Result as StoreResult, CryptoStore};
 
 use matrix_sdk_common::api;
 use matrix_sdk_common::events::{
-    forwarded_room_key::ForwardedRoomKeyEventContent,
-    room::encrypted::{CiphertextInfo, EncryptedEventContent, OlmV1Curve25519AesSha2Content},
-    room::message::MessageEventContent,
-    room_key::RoomKeyEventContent,
-    room_key_request::RoomKeyRequestEventContent,
-    Algorithm, AnySyncRoomEvent, AnyToDeviceEvent, EventJson, EventType, SyncMessageEvent,
-    ToDeviceEvent,
+    forwarded_room_key::ForwardedRoomKeyEventContent, room::encrypted::EncryptedEventContent,
+    room::message::MessageEventContent, room_key::RoomKeyEventContent,
+    room_key_request::RoomKeyRequestEventContent, Algorithm, AnySyncRoomEvent, AnyToDeviceEvent,
+    EventJson, EventType, SyncMessageEvent, ToDeviceEvent,
 };
 use matrix_sdk_common::identifiers::{DeviceId, RoomId, UserId};
 use matrix_sdk_common::uuid::Uuid;
@@ -50,7 +47,7 @@ use api::r0::{
     to_device::{send_event_to_device::Request as ToDeviceRequest, DeviceIdOrAllDevices},
 };
 
-use serde_json::{json, Value};
+use serde_json::Value;
 use tracing::{debug, error, info, instrument, trace, warn};
 
 /// A map from the algorithm and device id to a one-time key.
@@ -807,52 +804,12 @@ impl OlmMachine {
         event_type: EventType,
         content: Value,
     ) -> OlmResult<EncryptedEventContent> {
-        let identity_keys = self.account.identity_keys();
-
-        // TODO most of this could go into the session, the session already
-        // stores the curve key of the device, if we also store the ed25519 key
-        // with the session we'll only need to pass in the account to the
-        // session and all of this can live in the session.
-
-        let recipient_signing_key = recipient_device
-            .get_key(KeyAlgorithm::Ed25519)
-            .ok_or(EventError::MissingSigningKey)?;
-        let recipient_sender_key = recipient_device
-            .get_key(KeyAlgorithm::Curve25519)
-            .ok_or(EventError::MissingSigningKey)?;
-
-        let payload = json!({
-            "sender": self.user_id,
-            "sender_device": self.device_id,
-            "keys": {
-                "ed25519": identity_keys.ed25519(),
-            },
-            "recipient": recipient_device.user_id(),
-            "recipient_keys": {
-                "ed25519": recipient_signing_key,
-            },
-            "type": event_type,
-            "content": content,
-        });
-
-        let plaintext = cjson::to_string(&payload)
-            .unwrap_or_else(|_| panic!(format!("Can't serialize {} to canonical JSON", payload)));
-
-        let ciphertext = session.encrypt(&plaintext).await.to_tuple();
-
-        let message_type: usize = ciphertext.0.into();
-
-        let ciphertext = CiphertextInfo::new(ciphertext.1, (message_type as u32).into());
-
-        let mut content = BTreeMap::new();
-
-        content.insert(recipient_sender_key.to_owned(), ciphertext);
-
+        let message = session
+            .encrypt(self.account.clone(), recipient_device, event_type, content)
+            .await;
         self.store.save_sessions(&[session]).await?;
 
-        Ok(EncryptedEventContent::OlmV1Curve25519AesSha2(
-            OlmV1Curve25519AesSha2Content::new(content, identity_keys.curve25519().to_owned()),
-        ))
+        message
     }
 
     /// Should the client share a group session for the given room.

matrix_sdk_crypto/src/olm/account.rs

@@ -49,8 +49,8 @@ use super::{InboundGroupSession, OutboundGroupSession, Session};
 /// devices.
 #[derive(Clone)]
 pub struct Account {
-    user_id: Arc<UserId>,
-    device_id: Arc<Box<DeviceId>>,
+    pub(crate) user_id: Arc<UserId>,
+    pub(crate) device_id: Arc<Box<DeviceId>>,
     inner: Arc<Mutex<OlmAccount>>,
     identity_keys: Arc<IdentityKeys>,
     shared: Arc<AtomicBool>,

matrix_sdk_crypto/src/olm/mod.rs

@@ -149,7 +149,7 @@ pub(crate) mod test {
 
         let plaintext = "Hello world";
 
-        let message = bob_session.encrypt(plaintext).await;
+        let message = bob_session.encrypt_helper(plaintext).await;
 
         let prekey_message = match message.clone() {
             OlmMessage::PreKey(m) => m,

matrix_sdk_crypto/src/olm/session.rs

@@ -12,22 +12,35 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use matrix_sdk_common::instant::Instant;
+use std::collections::BTreeMap;
 use std::fmt;
 use std::sync::Arc;
 
-use matrix_sdk_common::locks::Mutex;
-
-pub use olm_rs::account::IdentityKeys;
 use olm_rs::errors::OlmSessionError;
 use olm_rs::session::OlmSession;
 use olm_rs::PicklingMode;
 
+use serde_json::{json, Value};
+
 pub use olm_rs::{
     session::{OlmMessage, PreKeyMessage},
     utility::OlmUtility,
 };
 
+use super::Account;
+use crate::error::{EventError, OlmResult};
+use crate::Device;
+
+use matrix_sdk_common::{
+    api::r0::keys::KeyAlgorithm,
+    events::{
+        room::encrypted::{CiphertextInfo, EncryptedEventContent, OlmV1Curve25519AesSha2Content},
+        EventType,
+    },
+    instant::Instant,
+    locks::Mutex,
+};
+
 /// Cryptographic session that enables secure communication between two
 /// `Account`s
 #[derive(Clone)]
@@ -71,12 +84,61 @@ impl Session {
     /// # Arguments
     ///
     /// * `plaintext` - The plaintext that should be encrypted.
-    pub async fn encrypt(&mut self, plaintext: &str) -> OlmMessage {
+    pub(crate) async fn encrypt_helper(&mut self, plaintext: &str) -> OlmMessage {
         let message = self.inner.lock().await.encrypt(plaintext);
         self.last_use_time = Arc::new(Instant::now());
         message
     }
 
+    /// Encrypt the given event content content as an m.room.encrypted event
+    /// content.
+    pub async fn encrypt(
+        &mut self,
+        account: Account,
+        recipient_device: &Device,
+        event_type: EventType,
+        content: Value,
+    ) -> OlmResult<EncryptedEventContent> {
+        let recipient_signing_key = recipient_device
+            .get_key(KeyAlgorithm::Ed25519)
+            .ok_or(EventError::MissingSigningKey)?;
+        let recipient_sender_key = recipient_device
+            .get_key(KeyAlgorithm::Curve25519)
+            .ok_or(EventError::MissingSigningKey)?;
+
+        let payload = json!({
+            "sender": account.user_id.to_string(),
+            "sender_device": account.device_id.as_ref(),
+            "keys": {
+                "ed25519": account.identity_keys().ed25519(),
+            },
+            "recipient": recipient_device.user_id(),
+            "recipient_keys": {
+                "ed25519": recipient_signing_key,
+            },
+            "type": event_type,
+            "content": content,
+        });
+
+        let plaintext = cjson::to_string(&payload)
+            .unwrap_or_else(|_| panic!(format!("Can't serialize {} to canonical JSON", payload)));
+
+        let ciphertext = self.encrypt_helper(&plaintext).await.to_tuple();
+
+        let message_type = ciphertext.0;
+        let ciphertext = CiphertextInfo::new(ciphertext.1, (message_type as u32).into());
+
+        let mut content = BTreeMap::new();
+        content.insert(recipient_sender_key.to_owned(), ciphertext);
+
+        Ok(EncryptedEventContent::OlmV1Curve25519AesSha2(
+            OlmV1Curve25519AesSha2Content::new(
+                content,
+                account.identity_keys().curve25519().to_owned(),
+            ),
+        ))
+    }
+
     /// Check if a pre-key Olm message was encrypted for this session.
     ///
     /// Returns true if it matches, false if not and a OlmSessionError if there