Merge pull request 'feat(auth): persist the trust token returned by the SSO exchange' (#29) from feat/sso-trusted-device into main

Reviewed-on: #29
Reviewed-by: Colby Whitlock <whitlocktech@gmail.com>

app/src/main/java/com/runicgateway/app/core/auth/sso/SsoAuthManager.kt

@@ -5,6 +5,7 @@ package com.runicgateway.app.core.auth.sso
 
 import com.runicgateway.app.BuildConfig
 import com.runicgateway.app.core.auth.SessionManager
+import com.runicgateway.app.core.auth.TrustTokenStore
 import com.runicgateway.app.core.net.BaseUrlHolder
 import com.runicgateway.app.data.api.SsoApi
 import com.runicgateway.app.data.api.dto.MobileSsoExchangeRequest
@@ -49,6 +50,7 @@ class SsoAuthManager @Inject constructor(
     private val sessionManager: SessionManager,
     private val baseUrlHolder: BaseUrlHolder,
     private val pendingStore: PendingSsoStore,
+    private val trustTokenStore: TrustTokenStore,
 ) {
 
     /** Why an SSO attempt ended, for a friendly inline message on the login screen. */
@@ -193,6 +195,14 @@ class SsoAuthManager @Inject constructor(
                 _outcome.value = Outcome.Failed(Failure.SERVER)
                 return
             }
+            // The user ticked "trust this device" on the TOTP form inside the Custom
+            // Tab. That tab's cookie already covers future SSO sign-ins; persisting
+            // the token the exchange handed back is what lets a native PASSWORD login
+            // on this device skip the code too (TRUSTED_DEVICES_MFA.md). Scoped to the
+            // username exactly like the password path, so it is never replayed for a
+            // different account on a shared device. Saved BEFORE onSignedIn so a
+            // process death mid-callback can't lose it.
+            body.trustToken?.let { trustTokenStore.save(body.user.username, it) }
             sessionManager.onSignedIn(body.accessToken, body.refreshToken, body.user)
             _outcome.value = Outcome.Success
             return

app/src/test/java/com/runicgateway/app/core/auth/sso/SsoAuthManagerTest.kt

@@ -7,6 +7,7 @@ import com.runicgateway.app.core.auth.Session
 import com.runicgateway.app.core.auth.SessionManager
 import com.runicgateway.app.core.auth.StoredSession
 import com.runicgateway.app.core.auth.TokenStore
+import com.runicgateway.app.core.auth.TrustTokenStore
 import com.runicgateway.app.core.net.BaseUrlHolder
 import com.runicgateway.app.data.api.SsoApi
 import com.runicgateway.app.data.api.dto.MobileSsoExchangeRequest
@@ -45,6 +46,17 @@ class SsoAuthManagerTest {
         override fun clear() { pending = null }
     }
 
+    /** In-memory stand-in for the encrypted trust-token store, scoped by username
+     *  the same way the production impl is. */
+    private class FakeTrustTokenStore : TrustTokenStore {
+        var owner: String? = null
+        var token: String? = null
+        override fun tokenFor(username: String): String? =
+            if (owner.equals(username, ignoreCase = true)) token else null
+        override fun save(username: String, token: String) { owner = username; this.token = token }
+        override fun clear() { owner = null; token = null }
+    }
+
     /** Records the exchange it was called with and returns a scripted response. */
     private class FakeSsoApi(
         private val exchangeResult: () -> Response<MobileTokenResponse>,
@@ -76,10 +88,11 @@ class SsoAuthManagerTest {
         session: SessionManager,
         base: String? = "https://shard.example.com/",
         store: PendingSsoStore = FakePendingSsoStore(),
+        trust: TrustTokenStore = FakeTrustTokenStore(),
     ): SsoAuthManager {
         val holder = BaseUrlHolder()
         if (base != null) holder.set(base.toHttpUrl())
-        return SsoAuthManager(api, session, holder, store)
+        return SsoAuthManager(api, session, holder, store, trust)
     }
 
     /** Build a start URL and pull the generated `state` back out of it. */
@@ -120,6 +133,38 @@ class SsoAuthManagerTest {
         assertEquals(SsoAuthManager.Outcome.Success, mgr.outcome.value)
     }
 
+    // Trusted devices over SSO (TRUSTED_DEVICES_MFA.md). Ticking "trust this device"
+    // on the TOTP form inside the Custom Tab trusts that browser via cookie; the
+    // exchange additionally hands the APP its own token so a native password login
+    // on this device skips the code too. Before this, SSO ignored trust entirely.
+    @Test fun `a trustToken on the exchange response is persisted for the signed-in user`() = runTest {
+        val api = FakeSsoApi { Response.success(tokenPair().copy(trustToken = "opaque-trust")) }
+        val session = SessionManager(FakeTokenStore())
+        val trust = FakeTrustTokenStore()
+        val mgr = managerWith(api, session, trust = trust)
+
+        val state = startAndState(mgr)
+        mgr.complete(state = state, code = "auth-code-1", error = null)
+
+        assertEquals(SsoAuthManager.Outcome.Success, mgr.outcome.value)
+        assertEquals("opaque-trust", trust.tokenFor("alice"))
+        // Scoped to the account that minted it — never replayed for someone else.
+        assertNull(trust.tokenFor("mallory"))
+    }
+
+    @Test fun `no trustToken on the response leaves the store untouched`() = runTest {
+        val api = FakeSsoApi { Response.success(tokenPair()) }
+        val session = SessionManager(FakeTokenStore())
+        val trust = FakeTrustTokenStore()
+        val mgr = managerWith(api, session, trust = trust)
+
+        val state = startAndState(mgr)
+        mgr.complete(state = state, code = "auth-code-1", error = null)
+
+        assertEquals(SsoAuthManager.Outcome.Success, mgr.outcome.value)
+        assertNull(trust.tokenFor("alice"))
+    }
+
     @Test fun `state mismatch fails without exchanging`() = runTest {
         val api = FakeSsoApi { Response.success(tokenPair()) }
         val session = SessionManager(FakeTokenStore())