crypto: Add a method to check the state of our private cross signing keys

matrix_sdk_crypto/src/lib.rs

@@ -50,8 +50,8 @@ pub use identities::{
 };
 pub use machine::OlmMachine;
 pub use matrix_qrcode;
-pub use olm::EncryptionSettings;
 pub(crate) use olm::ReadOnlyAccount;
+pub use olm::{CrossSigningStatus, EncryptionSettings};
 pub use requests::{
     IncomingResponse, KeysQueryRequest, OutgoingRequest, OutgoingRequests,
     OutgoingVerificationRequest, RoomMessageRequest, ToDeviceRequest,

matrix_sdk_crypto/src/machine.rs

@@ -51,9 +51,9 @@ use crate::{
     gossiping::GossipMachine,
     identities::{user::UserIdentities, Device, IdentityManager, UserDevices},
     olm::{
-        Account, EncryptionSettings, ExportedRoomKey, GroupSessionKey, IdentityKeys,
-        InboundGroupSession, OlmDecryptionInfo, PrivateCrossSigningIdentity, ReadOnlyAccount,
-        SessionType,
+        Account, CrossSigningStatus, EncryptionSettings, ExportedRoomKey, GroupSessionKey,
+        IdentityKeys, InboundGroupSession, OlmDecryptionInfo, PrivateCrossSigningIdentity,
+        ReadOnlyAccount, SessionType,
     },
     requests::{IncomingResponse, OutgoingRequest, UploadSigningKeysRequest},
     session_manager::{GroupSessionManager, SessionManager},
@@ -1254,6 +1254,14 @@ impl OlmMachine {
 
         Ok(exported)
     }
+
+    /// Get the status of the private cross signing keys.
+    ///
+    /// This can be used to check which private cross signing keys we have
+    /// stored locally.
+    pub async fn cross_signing_status(&self) -> CrossSigningStatus {
+        self.user_identity.lock().await.status().await
+    }
 }
 
 #[cfg(test)]

matrix_sdk_crypto/src/olm/mod.rs

@@ -34,7 +34,7 @@ use matrix_sdk_common::instant::{Duration, Instant};
 pub use olm_rs::{account::IdentityKeys, PicklingMode};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 pub use session::{PickledSession, Session, SessionPickle};
-pub use signing::{PickledCrossSigningIdentity, PrivateCrossSigningIdentity};
+pub use signing::{CrossSigningStatus, PickledCrossSigningIdentity, PrivateCrossSigningIdentity};
 pub(crate) use utility::Utility;
 
 pub(crate) fn serialize_instant<S>(instant: &Instant, serializer: S) -> Result<S::Ok, S::Error>

matrix_sdk_crypto/src/olm/signing/mod.rs

@@ -70,6 +70,20 @@ pub struct PickledCrossSigningIdentity {
     pub pickle: String,
 }
 
+/// Struct representing the state of our private cross signing keys, it shows
+/// which private cross signing keys we have locally stored.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct CrossSigningStatus {
+    /// Do we have the master key.
+    pub has_master: bool,
+    /// Do we have the self signing key, this one is necessary to sign our own
+    /// devices.
+    pub has_self_signing: bool,
+    /// Do we have the user signing key, this one is necessary to sign other
+    /// users.
+    pub has_user_signing: bool,
+}
+
 impl PrivateCrossSigningIdentity {
     /// Get the user id that this identity belongs to.
     pub fn user_id(&self) -> &UserId {
@@ -108,6 +122,16 @@ impl PrivateCrossSigningIdentity {
         self.master_key.lock().await.is_some()
     }
 
+    /// Get the status of our private cross signing keys, i.e. if we have the
+    /// master key and the subkeys.
+    pub async fn status(&self) -> CrossSigningStatus {
+        CrossSigningStatus {
+            has_master: self.has_master_key().await,
+            has_self_signing: self.can_sign_devices().await,
+            has_user_signing: self.can_sign_users().await,
+        }
+    }
+
     /// Get the public part of the master key, if we have one.
     pub async fn master_public_key(&self) -> Option<MasterPubkey> {
         self.master_key.lock().await.as_ref().map(|m| m.public_key.to_owned())

matrix_sdk_crypto/src/store/mod.rs

@@ -78,6 +78,7 @@ use crate::{
         ReadOnlyAccount, Session,
     },
     verification::VerificationMachine,
+    CrossSigningStatus,
 };
 
 /// A `CryptoStore` specific result type.