Expose forwarder and forwarderDevice on DecryptedRoomEvent. (#284)

Expose information about the forwarder for events that were decrypted using a key from an [MSC4268](matrix-org/matrix-spec-proposals#4268) key bundle.

Signed-off-by: Skye Elliot <actuallyori@gmail.com>

Author: kaylendog

CHANGELOG.md

@@ -1,5 +1,25 @@
 # UNRELEASED
 
+-   Expose information about the forwarder for events that were decrypted using a
+    key from an [MSC4268](https://github.com/matrix-org/matrix-spec-proposals/pull/4268)
+    key bundle.
+    ([#270](https://github.com/matrix-org/matrix-sdk-crypto-wasm/pull/284/changes))
+-   Update matrix-rust-sdk to `cd9f433`, which includes:
+
+    -   Add field `forwarder` of type `ForwarderInfo` to `EncryptionInfo`, which
+        exposes information about the forwarder of the keys with which an event was
+        encrypted if they were shared as part of an [MSC4268](https://github.com/matrix-org/matrix-spec-proposals/pull/4268)
+        room key bundle.
+        ([#5945](https://github.com/matrix-org/matrix-rust-sdk/pull/5945)).
+    -   Added a new field `forwarder` to `InboundGroupSession` of type `ForwarderData`,
+        which stores information about the forwarder of a session shared in a room key
+        bundle under [MSC4268](https://github.com/matrix-org/matrix-spec-proposals/pull/4268).
+        ([#5980](https://github.com/matrix-org/matrix-rust-sdk/pull/5980)
+    -   The `OutboundGroupSession` and `OlmMachine` now return the `EncryptionInfo` used
+        when encrypting raw events.
+        ([#5936](https://github.com/matrix-org/matrix-rust-sdk/pull/5936))
+        **Note:** The WASM bindings are not affected by this change.
+
 # matrix-sdk-crypto-wasm v16.0.0
 
 -   Add new property `MegolmDecryptionError.withheldCode`, which returns a withheld

Cargo.lock

@@ -64,9 +64,9 @@ futures-util = "0.3.27"
 getrandom = { version = "0.3.0", features = ["wasm_js"] }
 http = "1.1.0"
 js-sys = "0.3.49"
-matrix-sdk-common = { features = ["js",  "experimental-encrypted-state-events"], git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "183116a4b1888039ad4d1714ac0d97f1375cc45a" }
-matrix-sdk-indexeddb = { default-features = false, features = ["e2e-encryption"], git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "183116a4b1888039ad4d1714ac0d97f1375cc45a" }
-matrix-sdk-qrcode = { optional = true, git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "183116a4b1888039ad4d1714ac0d97f1375cc45a" }
+matrix-sdk-common = { features = ["js",  "experimental-encrypted-state-events"], git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "cd9f433358586e8717417fc043650f46362aa14c" }
+matrix-sdk-indexeddb = { default-features = false, features = ["e2e-encryption"], git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "cd9f433358586e8717417fc043650f46362aa14c" }
+matrix-sdk-qrcode = { optional = true, git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "cd9f433358586e8717417fc043650f46362aa14c" }
 serde = "1.0.91"
 serde_json = "1.0.91"
 serde-wasm-bindgen = "0.6.5"
@@ -86,7 +86,7 @@ vergen-gitcl = { version = "1.0.0", features = ["build"] }
 default-features = false
 features = ["js", "automatic-room-key-forwarding", "experimental-encrypted-state-events"]
 git = "https://github.com/matrix-org/matrix-rust-sdk"
-rev = "183116a4b1888039ad4d1714ac0d97f1375cc45a"
+rev = "cd9f433358586e8717417fc043650f46362aa14c"
 
 [lints.rust]
 # Workaround for https://github.com/rustwasm/wasm-bindgen/issues/4283, while we work up the courage to upgrade

Cargo.toml

@@ -464,6 +464,7 @@ fn libolm_pickled_megolm_session_to_rust_pickled_session(
         sender_key,
         signing_key: sender_signing_keys,
         sender_data: Default::default(),
+        forwarder_data: None,
         room_id: libolm_session
             .room_id
             .clone()

src/libolm_migration.rs

@@ -213,6 +213,25 @@ impl DecryptedRoomEvent {
     pub fn shield_state(&self, strict: bool) -> encryption::ShieldState {
         self.encryption_info.shield_state(strict)
     }
+
+    /// If the keys for this message were shared-on-invite as part of an
+    /// [MSC4268] key bundle, the ID of the user who sent us the bundle.
+    ///
+    /// [MSC4268]: https://github.com/matrix-org/matrix-spec-proposals/pull/4268
+    #[wasm_bindgen(getter, js_name = "forwarder")]
+    pub fn forwarder(&self) -> Option<identifiers::UserId> {
+        self.encryption_info.forwarder.clone()
+    }
+
+    /// If the keys for this message were shared-on-invite as part of an
+    /// [MSC4268] key bundle, the ID of the device from which this bundle
+    /// was sent.
+    ///
+    /// [MSC4268]: https://github.com/matrix-org/matrix-spec-proposals/pull/4268
+    #[wasm_bindgen(getter, js_name = "forwarderDevice")]
+    pub fn forwarder_device(&self) -> Option<identifiers::DeviceId> {
+        self.encryption_info.forwarder_device.clone()
+    }
 }
 
 impl TryFrom<matrix_sdk_common::deserialized_responses::DecryptedRoomEvent> for DecryptedRoomEvent {
@@ -244,6 +263,18 @@ pub struct EncryptionInfo {
     #[wasm_bindgen(getter_with_clone, js_name = "senderDevice")]
     pub sender_device: Option<identifiers::DeviceId>,
 
+    /// The ID of the user who sent us the keys with which we decrypted this
+    /// event as part of an MSC4268 key bundle, if present. Only applicable for
+    /// room events.
+    #[wasm_bindgen(getter_with_clone)]
+    pub forwarder: Option<identifiers::UserId>,
+
+    /// The device ID of the user who sent us the keys with which we decrypted
+    /// this event as part of an MSC4268 key bundle, if present. Only applicable
+    /// for room events.
+    #[wasm_bindgen(getter_with_clone, js_name = "forwarderDevice")]
+    pub forwarder_device: Option<identifiers::DeviceId>,
+
     /// The base64-encoded public Curve25519 key of the device that created the
     /// megolm decryption key originally.
     #[wasm_bindgen(getter_with_clone, js_name = "senderCurve25519Key")]
@@ -299,6 +330,8 @@ impl TryFrom<Arc<matrix_sdk_common::deserialized_responses::EncryptionInfo>> for
                         .get(&ruma::DeviceKeyAlgorithm::Ed25519)
                         .cloned()
                         .into(),
+                    forwarder: value.forwarder.as_ref().map(|info| info.user_id.clone().into()),
+                    forwarder_device: value.forwarder.as_ref().map(|info| info.device_id.clone().into()),
                     verification_state: value.verification_state.clone(),
                 })
             }

src/responses.rs

@@ -137,6 +137,10 @@ describe("encrypted history sharing/decrypting", () => {
             const decryptedData = await receiverMachine.decryptRoomEvent(encryptedEvent, room, decryptionSettings);
             const decryptedEvent = JSON.parse(decryptedData.event);
             expect(decryptedEvent.content.body).toEqual("Hi!");
+
+            // ... and be able to look up who forwarded them the decryption key.
+            expect(decryptedData.forwarder?.toString()).toEqual("@alice:example.org");
+            expect(decryptedData.forwarderDevice?.toString()).toEqual("A");
         });
     });
 });