Fix crashes when entering an empty or incorrect password

firmware/acid-firmware/src/ui/mod.rs

@@ -55,11 +55,18 @@ pub mod window_adapter;
 
 slint::include_modules!();
 
+#[derive(Clone, Copy)]
+struct EmptyPassword;
+
 fn spectre_derive_user_key(
     username: &CStr,
     password: &CStr,
     encrypted_key: Option<Key>,
-) -> SpectreUserKey {
+) -> Result<SpectreUserKey, EmptyPassword> {
+    if password.is_empty() {
+        return Err(EmptyPassword);
+    }
+
     if let Some(encrypted_key) = encrypted_key {
         ACTIVE_ENCRYPTED_USER_KEY.lock(|user_key| {
             user_key.set(encrypted_key);
@@ -84,7 +91,7 @@ fn spectre_derive_user_key(
         // TODO: Erase memory before freeing
         __spre_free(user_key as *const _ as *mut _);
 
-        user_key_stack
+        Ok(user_key_stack)
     }
 }
 
@@ -338,14 +345,16 @@ impl State {
 
     fn process_callback_message(
         state_rc: &Rc<RefCell<State>, PsramAllocator>,
-        message: CallbackMessage,
+        mut message: CallbackMessage,
     ) {
         let view = state_rc.borrow().view;
-        match view {
+        while let Some(next_message) = match view {
             AppState::Login => StateLogin::process_callback_message(state_rc, message),
             AppState::Users => StateUsers::process_callback_message(state_rc, message),
             AppState::UserEdit => StateUserEdit::process_callback_message(state_rc, message),
             AppState::UserSites => StateUserSites::process_callback_message(state_rc, message),
+        } {
+            message = next_message
         }
     }
 
@@ -392,7 +401,8 @@ trait AppViewTrait {
     fn process_callback_message(
         _state_rc: &Rc<RefCell<State>, PsramAllocator>,
         _message: CallbackMessage,
-    ) {
+    ) -> Option<CallbackMessage> {
+        None
     }
 }
 
@@ -403,7 +413,7 @@ impl AppViewTrait for StateLogin {
     fn process_callback_message(
         state_rc: &Rc<RefCell<State>, PsramAllocator>,
         message: CallbackMessage,
-    ) {
+    ) -> Option<CallbackMessage> {
         let mut state = state_rc.borrow_mut();
         match message {
             CallbackMessage::Login(CallbackMessageLogin::PwAccepted {
@@ -413,14 +423,18 @@ impl AppViewTrait for StateLogin {
             }) => {
                 let Some(user) = state.users.users.row_data(user_index as usize) else {
                     error!("Failed to find a user with index {user_index}.");
-                    return;
+                    return None;
                 };
                 let username_c = CString::new(&*user.username)
                     .expect("Username cannot be converted to a C string.");
                 let password_c =
                     CString::new(&*password).expect("Password cannot be converted to a C string.");
-                let user_key =
-                    spectre_derive_user_key(&username_c, &password_c, Some(user.encrypted_key));
+                let Ok(user_key) =
+                    spectre_derive_user_key(&username_c, &password_c, Some(user.encrypted_key))
+                else {
+                    error!("Password empty.");
+                    return None;
+                };
 
                 // {
                 //     let mut write = db.write_transaction().await;
@@ -459,14 +473,10 @@ impl AppViewTrait for StateLogin {
                 // }
 
                 if user.key_id != user_key.keyID.bytes {
-                    State::process_callback_message(
-                        state_rc,
-                        CallbackMessage::Login(CallbackMessageLogin::LoginResult {
-                            username: user.username,
-                            result: LoginResult::Failure,
-                        }),
-                    );
-                    return;
+                    return Some(CallbackMessage::Login(CallbackMessageLogin::LoginResult {
+                        username: user.username,
+                        result: LoginResult::Failure,
+                    }));
                 }
 
                 slint::spawn_local({
@@ -549,6 +559,8 @@ impl AppViewTrait for StateLogin {
             }
             _ => (),
         }
+
+        None
     }
 }
 
@@ -559,7 +571,7 @@ impl AppViewTrait for StateUsers {
     fn process_callback_message(
         state_rc: &Rc<RefCell<State>, PsramAllocator>,
         message: CallbackMessage,
-    ) {
+    ) -> Option<CallbackMessage> {
         let mut state = state_rc.borrow_mut();
         match message {
             CallbackMessage::Escape => {
@@ -577,6 +589,8 @@ impl AppViewTrait for StateUsers {
             }
             _ => (),
         }
+
+        None
     }
 }
 
@@ -592,7 +606,7 @@ impl AppViewTrait for StateUserEdit {
     fn process_callback_message(
         state_rc: &Rc<RefCell<State>, PsramAllocator>,
         message: CallbackMessage,
-    ) {
+    ) -> Option<CallbackMessage> {
         let state = state_rc.clone();
         let mut state = state.borrow_mut();
         match message {
@@ -630,7 +644,7 @@ impl AppViewTrait for StateUserEdit {
             }) => {
                 let Some(password) = state.state_user_edit.password.as_ref() else {
                     warn!("Attempted to compute a key ID when no password has been entered.");
-                    return;
+                    return None;
                 };
 
                 let mut key: Key = [0; _];
@@ -654,14 +668,18 @@ impl AppViewTrait for StateUserEdit {
                         }
                     };
                     state.window.set_user_edit_key_error(message);
-                    return;
+                    return None;
                 }
 
                 let username_c = CString::new(&*state.state_user_edit.username)
                     .expect("Username cannot be converted to a C string.");
                 let password_c =
                     CString::new(&**password).expect("Password cannot be converted to a C string.");
-                let user_key = spectre_derive_user_key(&username_c, &password_c, Some(key));
+                let Ok(user_key) = spectre_derive_user_key(&username_c, &password_c, Some(key))
+                else {
+                    error!("Password empty.");
+                    return None;
+                };
 
                 state.window.set_user_edit_key_error(SharedString::new());
                 state.window.set_user_edit_key_id(
@@ -683,7 +701,7 @@ impl AppViewTrait for StateUserEdit {
                 )) = state.state_user_edit.encrypted_key.take()
                 else {
                     warn!("Encrypted key is not set.");
-                    return;
+                    return None;
                 };
 
                 // If a user with that username already exists, overwrite it.
@@ -730,6 +748,8 @@ impl AppViewTrait for StateUserEdit {
             }
             _ => (),
         }
+
+        None
     }
 }
 
@@ -745,7 +765,7 @@ impl AppViewTrait for StateUserSites {
     fn process_callback_message(
         state_rc: &Rc<RefCell<State>, PsramAllocator>,
         message: CallbackMessage,
-    ) {
+    ) -> Option<CallbackMessage> {
         let state = state_rc.clone();
         let mut state = state.borrow_mut();
         match message {
@@ -763,12 +783,12 @@ impl AppViewTrait for StateUserSites {
             }) => {
                 let Some(user_sites) = state.state_user_sites.as_mut() else {
                     error!("User sites uninitialized.");
-                    return;
+                    return None;
                 };
                 let Some(site_list_entry) = user_sites.site_list.row_data(site_list_index as usize)
                 else {
                     error!("Invalid site list entry index: {site_list_index}");
-                    return;
+                    return None;
                 };
                 warn!("Site name accepted: {site_list_entry:?}");
                 let site_name = match site_list_entry {
@@ -809,6 +829,8 @@ impl AppViewTrait for StateUserSites {
             }
             _ => (),
         }
+
+        None
     }
 }