Add regression test: Default to connecting state on corrupt state cache

mullvad-daemon/src/target_state.rs

@@ -1,5 +1,6 @@
 use mullvad_types::states::TargetState;
 use std::{
+    future::Future,
     ops::Deref,
     path::{Path, PathBuf},
 };
@@ -21,48 +22,76 @@ impl PersistentTargetState {
     /// Initialize using the current target state (if there is one)
     pub async fn new(cache_dir: &Path) -> Self {
         let cache_path = cache_dir.join(TARGET_START_STATE_FILE);
-        let mut update_cache = false;
-        let state = match fs::read_to_string(&cache_path).await {
+        let TargetStateInner {
+            state,
+            update_cache,
+        } = Self::read_target_state(&cache_path, fs::read_to_string).await;
+        let state = PersistentTargetState {
+            state,
+            cache_path,
+            locked: false,
+        };
+        if update_cache {
+            state.save().await;
+        }
+        state
+    }
+
+    /// Construct a [`TargetState`] from cache.
+    ///
+    /// `read_cache` allows the caller to decide how to read from a cache of
+    /// [`TargetState`].
+    ///
+    /// This function will always succeed, even in the presence of IO
+    /// operations. Errors are handled gracefully by defaulting to safe target
+    /// states if necessary.
+    async fn read_target_state<F, R>(cache: &Path, read_cache: F) -> TargetStateInner
+    where
+        F: FnOnce(PathBuf) -> R,
+        R: Future<Output = io::Result<String>>,
+    {
+        match read_cache(cache.to_path_buf()).await {
             Ok(content) => serde_json::from_str(&content)
                 .map(|state| {
                     log::info!(
                         "Loaded cached target state \"{}\" from {}",
                         state,
-                        cache_path.display()
+                        cache.display()
                     );
-                    state
+                    TargetStateInner {
+                        state,
+                        update_cache: false,
+                    }
                 })
                 .unwrap_or_else(|error| {
                     log::error!(
                         "{}",
                         error.display_chain_with_msg("Failed to parse cached target tunnel state")
                     );
-                    update_cache = true;
-                    TargetState::Secured
+                    TargetStateInner {
+                        state: TargetState::Secured,
+                        update_cache: true,
+                    }
                 }),
+
+            Err(error) if error.kind() == io::ErrorKind::NotFound => {
+                log::debug!("No cached target state to load");
+                TargetStateInner {
+                    state: DEFAULT_TARGET_STATE,
+                    update_cache: false,
+                }
+            }
             Err(error) => {
-                if error.kind() == io::ErrorKind::NotFound {
-                    log::debug!("No cached target state to load");
-                    DEFAULT_TARGET_STATE
-                } else {
-                    log::error!(
-                        "{}",
-                        error.display_chain_with_msg("Failed to read cached target tunnel state")
-                    );
-                    update_cache = true;
-                    TargetState::Secured
+                log::error!(
+                    "{}",
+                    error.display_chain_with_msg("Failed to read cached target tunnel state")
+                );
+                TargetStateInner {
+                    state: TargetState::Secured,
+                    update_cache: true,
                 }
             }
-        };
-        let state = PersistentTargetState {
-            state,
-            cache_path,
-            locked: false,
-        };
-        if update_cache {
-            state.save().await;
         }
-        state
     }
 
     /// Override the current target state, if there is one
@@ -153,3 +182,70 @@ impl Deref for PersistentTargetState {
         &self.state
     }
 }
+
+/// The result of calling `read_target_state`.
+struct TargetStateInner {
+    state: TargetState,
+    /// In some circumstances, the target state cache should be updated on disk
+    /// upon initialization a [`PersistentTargetState`]. This is signaled to the
+    /// constructor of [`PersistentTargetState`] by setting this value to
+    /// `true`.
+    update_cache: bool,
+}
+
+impl Deref for TargetStateInner {
+    type Target = TargetState;
+
+    fn deref(&self) -> &Self::Target {
+        &self.state
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    static DUMMY_CACHE_DIR: &str = "target-state-test";
+
+    /// If no target state cache exist, the default target state is used. This
+    /// is the most basic check.
+    #[tokio::test]
+    async fn test_target_state_initialization_empty() {
+        let target_state =
+            PersistentTargetState::read_target_state(Path::new(DUMMY_CACHE_DIR), |_| async {
+                // A completely blank slate. No target state cache file has been created yet.
+                Err(io::ErrorKind::NotFound.into())
+            })
+            .await;
+        assert_eq!(*target_state, DEFAULT_TARGET_STATE);
+    }
+
+    /// If a target state cache exist with some target state, the state can be
+    /// read-back successfully.
+    #[tokio::test]
+    async fn test_target_state_initialization_existing() {
+        for cached_state in [TargetState::Secured, TargetState::Unsecured] {
+            let target_state =
+                PersistentTargetState::read_target_state(Path::new(DUMMY_CACHE_DIR), |_| async {
+                    Ok(serde_json::to_string(&cached_state).unwrap())
+                })
+                .await;
+            assert_eq!(*target_state, cached_state);
+        }
+    }
+
+    /// The state can not be read-back successfully if the state file has become
+    /// corrupt. In such cases, initializing a [`PersistentTargetState`] should
+    /// yield a "better safe than sorry"-target state of `Secured`.
+    #[tokio::test]
+    async fn test_target_corrupt_state_cache() {
+        let target_state =
+            PersistentTargetState::read_target_state(Path::new(DUMMY_CACHE_DIR), |_| async {
+                // Intentionally corrupt the target state cache.
+                Ok("Not a valid target state".to_string())
+            })
+            .await;
+        // Reading back a corrupt target state cache should yield `TargetState::Secured`.
+        assert_eq!(*target_state, TargetState::Secured);
+    }
+}

test/test-manager/src/tests/account.rs

@@ -324,7 +324,7 @@ pub async fn test_automatic_wireguard_rotation(
         .pubkey;
 
     // Stop daemon
-    rpc.set_mullvad_daemon_service_state(false)
+    rpc.stop_mullvad_daemon()
         .await
         .expect("Could not stop system service");
 
@@ -334,7 +334,7 @@ pub async fn test_automatic_wireguard_rotation(
         .expect("Could not change device.json to have an old created timestamp");
 
     // Start daemon
-    rpc.set_mullvad_daemon_service_state(true)
+    rpc.start_mullvad_daemon()
         .await
         .expect("Could not start system service");
 

test/test-manager/src/tests/tunnel_state.rs

@@ -335,3 +335,54 @@ pub async fn test_connected_state(
 
     Ok(())
 }
+
+/// Verify that the app defaults to the connecting state if it is started with a
+/// corrupt state cache.
+#[test_function]
+pub async fn test_connecting_state_when_corrupted_state_cache(
+    _: TestContext,
+    rpc: ServiceClient,
+    mullvad_client: ManagementServiceClient,
+) -> Result<(), Error> {
+    // The test should start in a disconnected state. Normally this would be
+    // preserved when restarting the app, i.e. the user would still be
+    // disconnected after a successfull restart. However, as we will
+    // intentionally corrupt the state target cache the user should end up in
+    // the connecting/connected state, *not in the disconnected state*, upon
+    // restart.
+
+    // Stopping the app should write to the state target cache.
+    log::info!("Stopping the app");
+    rpc.stop_mullvad_daemon().await?;
+
+    // Intentionally corrupt the state cache. Note that we can not simply remove
+    // the cache, as this will put the app in the default target state which is
+    // 'unsecured'.
+    log::info!("Figuring out where state cache resides on test runner ..");
+    let state_cache = rpc
+        .find_mullvad_app_cache_dir()
+        .await?
+        .join("target-start-state.json");
+    log::info!(
+        "Intentionally writing garbage to the state cache {file}",
+        file = state_cache.display()
+    );
+    rpc.write_file(state_cache, "cookie was here".into())
+        .await?;
+
+    // Start the app & make sure that we start in the 'connecting state'. The
+    // side-effect of this is that no network traffic is allowed to leak.
+    log::info!("Starting the app back up again");
+    rpc.start_mullvad_daemon().await?;
+    wait_for_tunnel_state(mullvad_client.clone(), |state| !state.is_disconnected())
+        .await
+        .map_err(|err| {
+            log::error!("App did not start in an expected state. \
+                        App is not in either `Connecting` or `Connected` state after starting with corrupt state cache! \
+                        There is a possibility of leaks during app startup ");
+            err
+        })?;
+    log::info!("App successfully recovered from a corrupt tunnel state cache.");
+
+    Ok(())
+}

test/test-rpc/src/client.rs

@@ -1,5 +1,6 @@
 use std::{
     collections::HashMap,
+    path::Path,
     time::{Duration, SystemTime},
 };
 
@@ -51,7 +52,7 @@ impl ServiceClient {
         self.client.uninstall_app(ctx, env).await?
     }
 
-    /// Execute a program.
+    /// Execute a program with additional environment-variables set.
     pub async fn exec_env<
         I: IntoIterator<Item = T>,
         M: IntoIterator<Item = (K, T)>,
@@ -151,6 +152,13 @@ impl ServiceClient {
             .await?
     }
 
+    /// Returns path of Mullvad app cache directorie on the test runner.
+    pub async fn find_mullvad_app_cache_dir(&self) -> Result<PathBuf, Error> {
+        self.client
+            .get_mullvad_app_cache_dir(tarpc::context::current())
+            .await?
+    }
+
     /// Send TCP packet
     pub async fn send_tcp(
         &self,
@@ -213,6 +221,51 @@ impl ServiceClient {
             .await?
     }
 
+    /// Restarts the app.
+    ///
+    /// Shuts down a running app, making it disconnect from any current tunnel
+    /// connection before starting the app again.
+    ///
+    /// # Note
+    /// This function will return *after* the app is running again, thus
+    /// blocking execution until then.
+    pub async fn restart_mullvad_daemon(&self) -> Result<(), Error> {
+        let _ = self
+            .client
+            .restart_mullvad_daemon(tarpc::context::current())
+            .await?;
+        Ok(())
+    }
+
+    /// Stop the app.
+    ///
+    /// Shuts down a running app, making it disconnect from any current tunnel
+    /// connection and making it write to caches.
+    ///
+    /// # Note
+    /// This function will return *after* the app has been stopped, thus
+    /// blocking execution until then.
+    pub async fn stop_mullvad_daemon(&self) -> Result<(), Error> {
+        let _ = self
+            .client
+            .stop_mullvad_daemon(tarpc::context::current())
+            .await?;
+        Ok(())
+    }
+
+    /// Start the app.
+    ///
+    /// # Note
+    /// This function will return *after* the app has been started, thus
+    /// blocking execution until then.
+    pub async fn start_mullvad_daemon(&self) -> Result<(), Error> {
+        let _ = self
+            .client
+            .start_mullvad_daemon(tarpc::context::current())
+            .await?;
+        Ok(())
+    }
+
     pub async fn set_daemon_log_level(
         &self,
         verbosity_level: mullvad_daemon::Verbosity,
@@ -247,6 +300,21 @@ impl ServiceClient {
             .await?
     }
 
+    pub async fn write_file(&self, dest: impl AsRef<Path>, bytes: Vec<u8>) -> Result<(), Error> {
+        log::debug!(
+            "Writing {bytes} bytes to \"{file}\"",
+            bytes = bytes.len(),
+            file = dest.as_ref().display()
+        );
+        self.client
+            .write_file(
+                tarpc::context::current(),
+                dest.as_ref().to_path_buf(),
+                bytes,
+            )
+            .await?
+    }
+
     pub async fn reboot(&mut self) -> Result<(), Error> {
         log::debug!("Rebooting server");
 
@@ -262,23 +330,6 @@ impl ServiceClient {
         Ok(())
     }
 
-    pub async fn set_mullvad_daemon_service_state(&self, on: bool) -> Result<(), Error> {
-        self.client
-            .set_mullvad_daemon_service_state(tarpc::context::current(), on)
-            .await??;
-
-        self.mullvad_daemon_wait_for_state(|state| {
-            if on {
-                state == ServiceStatus::Running
-            } else {
-                state == ServiceStatus::NotRunning
-            }
-        })
-        .await?;
-
-        Ok(())
-    }
-
     pub async fn make_device_json_old(&self) -> Result<(), Error> {
         self.client
             .make_device_json_old(tarpc::context::current())