Always check result of sp_repr_read_mem for NULL

In cases where undefined or invalid XML is passed to sp_repr_read_mem(),
it will indicate failure by returning NULL.  All callers must check for
this and handle the error condition accordingly.

Fixes: lp: #1170248

Fixed bugs:
  - https://launchpad.net/bugs/1170248

(bzr r13556)

3 files changed, 7 insertions, 2 deletions

diff --git a/src/extension/prefdialog.cpp b/src/extension/prefdialog.cpp
index d1f83701f..3a384257c 100644
--- a/src/extension/prefdialog.cpp
+++ b/src/extension/prefdialog.cpp
@@ -90,6 +90,10 @@ PrefDialog::PrefDialog (Glib::ustring name, gchar const * help, Gtk::Widget * co
     if (_effect != NULL && !_effect->no_live_preview) {
         if (_param_preview == NULL) {
             XML::Document * doc = sp_repr_read_mem(live_param_xml, strlen(live_param_xml), NULL);
+            if (doc == NULL) {
+                std::cout << "Error encountered loading live parameter XML !!!" << std::endl;
+                return;
+            }
             _param_preview = Parameter::make(doc->root(), _effect);
         }
 
diff --git a/src/extension/system.cpp b/src/extension/system.cpp
index c244d9c16..45feb882f 100644
--- a/src/extension/system.cpp
+++ b/src/extension/system.cpp
@@ -556,7 +556,7 @@ build_from_file(gchar const *filename)
 }
 
 /**
- * \return   The module created
+ * \return   The module created, or NULL if buffer is invalid
  * \brief    This function creates a module from a buffer holding an
  *           XML description.
  * \param    buffer  The buffer holding the XML description of the module.
@@ -568,6 +568,7 @@ Extension *
 build_from_mem(gchar const *buffer, Implementation::Implementation *in_imp)
 {
     Inkscape::XML::Document *doc = sp_repr_read_mem(buffer, strlen(buffer), INKSCAPE_EXTENSION_URI);
+    g_return_val_if_fail(doc != NULL, NULL);
     Extension *ext = build_from_reprdoc(doc, in_imp);
     Inkscape::GC::release(doc);
     return ext;
diff --git a/src/inkscape.cpp b/src/inkscape.cpp
index 4b4c8c678..e312e15b9 100644
--- a/src/inkscape.cpp
+++ b/src/inkscape.cpp
@@ -945,7 +945,7 @@ bool inkscape_load_menus( Inkscape::Application * inkscape )
         inkscape->menus = sp_repr_read_mem(menus_skeleton, MENUS_SKELETON_SIZE, NULL);
     }
 
-    return (inkscape->menus != 0);
+    return (inkscape->menus != NULL);
 }