feat(auth): add seal-key-derived pubkey integrity tags with auth enforcement and unseal backfill

server/crates/arbiter-server/tests/user_agent/auth.rs

@@ -3,9 +3,11 @@ use arbiter_server::{
     actors::{
         GlobalActors,
         bootstrap::GetToken,
+        keyholder::Bootstrap,
         user_agent::{AuthPublicKey, UserAgentConnection, auth},
     },
     db::{self, schema},
+    safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use diesel::{ExpressionMethods as _, QueryDsl, insert_into};
 use diesel_async::RunQueryDsl;
@@ -165,3 +167,120 @@ pub async fn test_challenge_auth() {
 
     task.await.unwrap().unwrap();
 }
+
+#[tokio::test]
+#[test_log::test]
+pub async fn test_challenge_auth_rejects_integrity_tag_mismatch_when_unsealed() {
+    let db = db::create_test_pool().await;
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+
+    actors
+        .key_holder
+        .ask(Bootstrap {
+            seal_key_raw: SafeCell::new(b"test-seal-key".to_vec()),
+        })
+        .await
+        .unwrap();
+
+    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+
+    {
+        let mut conn = db.get().await.unwrap();
+        insert_into(schema::useragent_client::table)
+            .values((
+                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
+                schema::useragent_client::key_type.eq(1i32),
+                schema::useragent_client::pubkey_integrity_tag.eq(Some(vec![0u8; 32])),
+            ))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+    }
+
+    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, server_transport).await
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            bootstrap_token: None,
+        })
+        .await
+        .unwrap();
+
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(auth::Error::InvalidChallengeSolution)
+    ));
+}
+
+#[tokio::test]
+#[test_log::test]
+pub async fn test_challenge_auth_rejects_invalid_signature() {
+    let db = db::create_test_pool().await;
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+
+    let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
+    let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
+
+    // Pre-register key with key_type
+    {
+        let mut conn = db.get().await.unwrap();
+        insert_into(schema::useragent_client::table)
+            .values((
+                schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
+                schema::useragent_client::key_type.eq(1i32),
+            ))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+    }
+
+    let (server_transport, mut test_transport) = ChannelTransport::new();
+    let db_for_task = db.clone();
+    let task = tokio::spawn(async move {
+        let mut props = UserAgentConnection::new(db_for_task, actors);
+        auth::authenticate(&mut props, server_transport).await
+    });
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeRequest {
+            pubkey: AuthPublicKey::Ed25519(new_key.verifying_key()),
+            bootstrap_token: None,
+        })
+        .await
+        .unwrap();
+
+    let response = test_transport
+        .recv()
+        .await
+        .expect("should receive challenge");
+    let challenge = match response {
+        Ok(resp) => match resp {
+            auth::Outbound::AuthChallenge { nonce } => nonce,
+            other => panic!("Expected AuthChallenge, got {other:?}"),
+        },
+        Err(err) => panic!("Expected Ok response, got Err({err:?})"),
+    };
+
+    // Sign a different challenge value so signature format is valid but verification must fail.
+    let wrong_challenge = arbiter_proto::format_challenge(challenge + 1, &pubkey_bytes);
+    let signature = new_key.sign(&wrong_challenge);
+
+    test_transport
+        .send(auth::Inbound::AuthChallengeSolution {
+            signature: signature.to_bytes().to_vec(),
+        })
+        .await
+        .unwrap();
+
+    assert!(matches!(
+        task.await.unwrap(),
+        Err(auth::Error::InvalidChallengeSolution)
+    ));
+}

server/crates/arbiter-server/tests/user_agent/unseal.rs

@@ -2,14 +2,17 @@ use arbiter_server::{
     actors::{
         GlobalActors,
         keyholder::{Bootstrap, Seal},
-        user_agent::{UserAgentSession, session::connection::{
-            HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError,
-        }},
+        user_agent::{
+            UserAgentSession,
+            session::connection::{HandleUnsealEncryptedKey, HandleUnsealRequest, UnsealError},
+        },
     },
     db,
     safe_cell::{SafeCell, SafeCellHandle as _},
 };
 use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
+use diesel::{ExpressionMethods as _, QueryDsl as _, insert_into};
+use diesel_async::RunQueryDsl;
 use kameo::actor::Spawn as _;
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
@@ -149,3 +152,42 @@ pub async fn test_unseal_retry_after_invalid_key() {
         assert!(matches!(response, Ok(())));
     }
 }
+
+#[tokio::test]
+#[test_log::test]
+pub async fn test_unseal_backfills_missing_pubkey_integrity_tags() {
+    let seal_key = b"test-seal-key";
+    let (db, user_agent) = setup_sealed_user_agent(seal_key).await;
+
+    {
+        let mut conn = db.get().await.unwrap();
+        insert_into(arbiter_server::db::schema::useragent_client::table)
+            .values((
+                arbiter_server::db::schema::useragent_client::public_key
+                    .eq(vec![1u8, 2u8, 3u8, 4u8]),
+                arbiter_server::db::schema::useragent_client::key_type.eq(1i32),
+                arbiter_server::db::schema::useragent_client::pubkey_integrity_tag
+                    .eq(Option::<Vec<u8>>::None),
+            ))
+            .execute(&mut conn)
+            .await
+            .unwrap();
+    }
+
+    let encrypted_key = client_dh_encrypt(&user_agent, seal_key).await;
+    let response = user_agent.ask(encrypted_key).await;
+    assert!(matches!(response, Ok(())));
+
+    {
+        let mut conn = db.get().await.unwrap();
+        let tags: Vec<Option<Vec<u8>>> = arbiter_server::db::schema::useragent_client::table
+            .select(arbiter_server::db::schema::useragent_client::pubkey_integrity_tag)
+            .load(&mut conn)
+            .await
+            .unwrap();
+        assert!(
+            tags.iter()
+                .all(|tag| matches!(tag, Some(v) if v.len() == 32))
+        );
+    }
+}