crypto: log details of our public identity when we update it

For debugging, it's useful to have a record of what we believe our own public
cross-signing keys to be. Currently, we log the keys at startup if we restore
them from the database, but if we subsequently create, or download, a set of
keys, they aren't logged.

crates/matrix-sdk-crypto/src/store/crypto_store_wrapper.rs

@@ -126,6 +126,26 @@ impl CryptoStoreWrapper {
 
         self.store.save_changes(changes).await?;
 
+        // If we updated our own public identity, log it for debugging purposes
+        if tracing::level_enabled!(tracing::Level::DEBUG) {
+            for updated_identity in
+                identities.new.iter().chain(identities.changed.iter()).filter_map(|id| id.own())
+            {
+                let master_key = updated_identity.master_key().get_first_key();
+                let user_signing_key = updated_identity.user_signing_key().get_first_key();
+                let self_signing_key = updated_identity.self_signing_key().get_first_key();
+
+                debug!(
+                    ?master_key,
+                    ?user_signing_key,
+                    ?self_signing_key,
+                    previously_verified = updated_identity.was_previously_verified(),
+                    verified = updated_identity.is_verified(),
+                    "Stored our own identity"
+                );
+            }
+        }
+
         if !room_key_updates.is_empty() {
             // Ignore the result. It can only fail if there are no listeners.
             let _ = self.room_keys_received_sender.send(room_key_updates);

crates/matrix-sdk-crypto/src/types/cross_signing/self_signing.rs

@@ -2,6 +2,7 @@ use std::collections::btree_map::Iter;
 
 use ruma::{encryption::KeyUsage, OwnedDeviceKeyId, UserId};
 use serde::{Deserialize, Serialize};
+use vodozemac::Ed25519PublicKey;
 
 use super::{CrossSigningKey, SigningKey};
 use crate::{
@@ -33,6 +34,14 @@ impl SelfSigningPubkey {
         &self.0.usage
     }
 
+    /// Get the first available self signing key.
+    ///
+    /// There's usually only a single key so this will usually fetch the
+    /// only key.
+    pub fn get_first_key(&self) -> Option<Ed25519PublicKey> {
+        self.0.get_first_key_and_id().map(|(_, k)| k)
+    }
+
     /// Verify that the [`DeviceKeys`] have a valid signature from this
     /// self-signing key.
     pub fn verify_device_keys(&self, device_keys: &DeviceKeys) -> Result<(), SignatureError> {

crates/matrix-sdk-crypto/src/types/cross_signing/user_signing.rs

@@ -2,6 +2,7 @@ use std::collections::btree_map::Iter;
 
 use ruma::{encryption::KeyUsage, OwnedDeviceKeyId, UserId};
 use serde::{Deserialize, Serialize};
+use vodozemac::Ed25519PublicKey;
 
 use super::{CrossSigningKey, MasterPubkey, SigningKey};
 use crate::{olm::VerifyJson, types::SigningKeys, SignatureError};
@@ -29,6 +30,14 @@ impl UserSigningPubkey {
         &self.0.keys
     }
 
+    /// Get the first available user-signing key.
+    ///
+    /// There's usually only a single key so this will usually fetch the
+    /// only key.
+    pub fn get_first_key(&self) -> Option<Ed25519PublicKey> {
+        self.0.get_first_key_and_id().map(|(_, k)| k)
+    }
+
     /// Check if the given master key is signed by this user signing key.
     ///
     /// # Arguments