gresourcefile: Fix crash if called with a badly escaped URI

Return an invalid `GFile` instead, as is the custom for VFS functions.

Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>

Fixes: #3090

2 files changed, 29 insertions, 3 deletions

diff --git a/gio/gresourcefile.c b/gio/gresourcefile.c
index 488fa34e2..1621839cf 100644
--- a/gio/gresourcefile.c
+++ b/gio/gresourcefile.c
@@ -238,6 +238,7 @@ g_resource_file_new_for_path (const char *path)
   return G_FILE (resource);
 }
 
+/* Will return %NULL if @uri is malformed */
 GFile *
 _g_resource_file_new (const char *uri)
 {
@@ -245,6 +246,9 @@ _g_resource_file_new (const char *uri)
   char *path;
 
   path = g_uri_unescape_string (uri + strlen ("resource:"), NULL);
+  if (path == NULL)
+    return NULL;
+
   resource = g_resource_file_new_for_path (path);
   g_free (path);
 
diff --git a/gio/tests/vfs.c b/gio/tests/vfs.c
index edfa1b7ee..c94b40701 100644
--- a/gio/tests/vfs.c
+++ b/gio/tests/vfs.c
@@ -108,18 +108,39 @@ test_local (void)
   gchar **schemes;
 
   vfs = g_vfs_get_local ();
-  g_assert (g_vfs_is_active (vfs));
+  g_assert_true (g_vfs_is_active (vfs));
 
   file = g_vfs_get_file_for_uri (vfs, "not a good uri");
-  g_assert (G_IS_FILE (file));
+  g_assert_true (G_IS_FILE (file));
   g_object_unref (file);
 
   schemes = (gchar **)g_vfs_get_supported_uri_schemes (vfs);
 
-  g_assert (g_strv_length (schemes) > 0);
+  g_assert_cmpuint (g_strv_length (schemes), >, 0);
   g_assert_cmpstr (schemes[0], ==, "file");
 }
 
+static void
+test_resource_malformed_escaping (void)
+{
+  GVfs *vfs;
+  GFile *file;
+
+  g_test_bug ("https://gitlab.gnome.org/GNOME/glib/-/issues/3090");
+  g_test_summary ("Test that g_vfs_get_file_for_uri() returns an invalid file for an invalid URI");
+
+  vfs = g_vfs_get_local ();
+  g_assert_true (g_vfs_is_active (vfs));
+
+  file = g_vfs_get_file_for_uri (vfs, "resource:///%not-valid-escaping/gtk.css");
+  g_assert_true (G_IS_FILE (file));
+
+  /* This only returns %NULL if the file was constructed with an invalid URI: */
+  g_assert_null (g_file_get_uri_scheme (file));
+
+  g_object_unref (file);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -127,6 +148,7 @@ main (int argc, char *argv[])
 
   g_test_add_func ("/gvfs/local", test_local);
   g_test_add_func ("/gvfs/register-scheme", test_register_scheme);
+  g_test_add_func ("/gvfs/resource/malformed-escaping", test_resource_malformed_escaping);
 
   return g_test_run ();
 }