FontEditor+TextEditor+Playground: Refuse to load device files

This prevents the undefined behaviour that would come up as a result of
doing so. (For example: opening "infinite" devices like /dev/full will
result in an infinite loop until exhaustion of memory)

4 files changed, 31 insertions, 2 deletions

diff --git a/Userland/Applications/FontEditor/main.cpp b/Userland/Applications/FontEditor/main.cpp
index 7055b49708..db91ce1c51 100644
--- a/Userland/Applications/FontEditor/main.cpp
+++ b/Userland/Applications/FontEditor/main.cpp
@@ -80,7 +80,13 @@ int main(int argc, char** argv)
         path = "/tmp/saved.font";
         edited_font = static_ptr_cast<Gfx::BitmapFont>(Gfx::FontDatabase::default_font().clone());
     } else {
-        edited_font = static_ptr_cast<Gfx::BitmapFont>(Gfx::BitmapFont::load_from_file(path)->clone());
+        auto bitmap_font = Gfx::BitmapFont::load_from_file(path);
+        if (!bitmap_font) {
+            String message = String::formatted("Couldn't load font: {}\n", path);
+            GUI::MessageBox::show(nullptr, message, "Font Editor", GUI::MessageBox::Type::Error);
+            return 1;
+        }
+        edited_font = static_ptr_cast<Gfx::BitmapFont>(bitmap_font->clone());
         if (!edited_font) {
             String message = String::formatted("Couldn't load font: {}\n", path);
             GUI::MessageBox::show(nullptr, message, "Font Editor", GUI::MessageBox::Type::Error);
@@ -112,7 +118,13 @@ int main(int argc, char** argv)
         if (!open_path.has_value())
             return;
 
-        RefPtr<Gfx::BitmapFont> new_font = static_ptr_cast<Gfx::BitmapFont>(Gfx::BitmapFont::load_from_file(open_path.value())->clone());
+        auto bitmap_font = Gfx::BitmapFont::load_from_file(open_path.value());
+        if (!bitmap_font) {
+            String message = String::formatted("Couldn't load font: {}\n", open_path.value());
+            GUI::MessageBox::show(window, message, "Font Editor", GUI::MessageBox::Type::Error);
+            return;
+        }
+        RefPtr<Gfx::BitmapFont> new_font = static_ptr_cast<Gfx::BitmapFont>(bitmap_font->clone());
         if (!new_font) {
             String message = String::formatted("Couldn't load font: {}\n", open_path.value());
             GUI::MessageBox::show(window, message, "Font Editor", GUI::MessageBox::Type::Error);
diff --git a/Userland/Applications/TextEditor/TextEditorWidget.cpp b/Userland/Applications/TextEditor/TextEditorWidget.cpp
index 071076e9f0..09a946562f 100644
--- a/Userland/Applications/TextEditor/TextEditorWidget.cpp
+++ b/Userland/Applications/TextEditor/TextEditorWidget.cpp
@@ -639,6 +639,11 @@ bool TextEditorWidget::open_file(const String& path)
         return false;
     }
 
+    if (file->is_device()) {
+        GUI::MessageBox::show(window(), String::formatted("Opening \"{}\" failed: Can't open device files", path), "Error", GUI::MessageBox::Type::Error);
+        return false;
+    }
+
     m_editor->set_text(file->read_all());
     m_document_dirty = false;
     m_document_opening = true;
diff --git a/Userland/DevTools/Playground/main.cpp b/Userland/DevTools/Playground/main.cpp
index a542caa53f..592fd31526 100644
--- a/Userland/DevTools/Playground/main.cpp
+++ b/Userland/DevTools/Playground/main.cpp
@@ -139,6 +139,10 @@ int main(int argc, char** argv)
             GUI::MessageBox::show(window, String::formatted("Opening \"{}\" failed: {}", path, strerror(errno)), "Error", GUI::MessageBox::Type::Error);
             return 1;
         }
+        if (file->is_device()) {
+            GUI::MessageBox::show(window, String::formatted("Opening \"{}\" failed: Can't open device files", path), "Error", GUI::MessageBox::Type::Error);
+            return 1;
+        }
         editor.set_text(file->read_all());
     }
 
@@ -164,6 +168,11 @@ int main(int argc, char** argv)
             return;
         }
 
+        if (file->is_device()) {
+            GUI::MessageBox::show(window, String::formatted("Opening \"{}\" failed: Can't open device files", open_path.value()), "Error", GUI::MessageBox::Type::Error);
+            return;
+        }
+
         editor.set_text(file->read_all());
         editor.set_focus(true);
     }));
diff --git a/Userland/Libraries/LibGfx/BitmapFont.cpp b/Userland/Libraries/LibGfx/BitmapFont.cpp
index b26db96c15..376525064b 100644
--- a/Userland/Libraries/LibGfx/BitmapFont.cpp
+++ b/Userland/Libraries/LibGfx/BitmapFont.cpp
@@ -172,6 +172,9 @@ size_t BitmapFont::glyph_count_by_type(FontTypes type)
 
 RefPtr<BitmapFont> BitmapFont::load_from_file(const StringView& path)
 {
+    if (Core::File::is_device(path))
+        return nullptr;
+
     auto file_or_error = MappedFile::map(path);
     if (file_or_error.is_error())
         return nullptr;