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malcontent-control: Fix use-after-free when closing 

Sometimes, when closing the application,
`flush_update_blacklisted_apps()` would be called after
`MctRestrictApplicationsSelector` had been destroyed, leading to a
critical.

This was because the `MctRestrictApplicationsDialog` was being disposed
early due to its `destroy-with-parent` property being set. The dispose
function of `MctUserControls` was run several times due to GTK calling
`g_object_run_dispose()`, and the critical would be emitted the second
time.

Make the dispose function’s call to `flush_update_blacklisted_apps()` be
safe for multiple dispose calls, and ensure the dialog isn’t destroyed
too early.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
This commit is contained in:
Philip Withnall 2020-01-29 17:37:12 +00:00
parent 00bb439f6e
commit 695ee10235
2 changed files with 12 additions and 2 deletions
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12
malcontent-control/user-controls.c
View File

@ -62,6 +62,7 @@ struct _MctUserControls
guint selected_age; /* @oars_disabled_age to disable OARS */ guint selected_age; /* @oars_disabled_age to disable OARS */
guint blacklist_apps_source_id; guint blacklist_apps_source_id;
gboolean flushed_on_dispose;
}; };
static gboolean blacklist_apps_cb (gpointer data); static gboolean blacklist_apps_cb (gpointer data);
@ -650,6 +651,9 @@ mct_user_controls_finalize (GObject *object)
g_clear_pointer (&self->filter, mct_app_filter_unref); g_clear_pointer (&self->filter, mct_app_filter_unref);
g_clear_object (&self->manager); g_clear_object (&self->manager);
/* Hopefully we don’t have data loss. */
g_assert (self->flushed_on_dispose);
G_OBJECT_CLASS (mct_user_controls_parent_class)->finalize (object); G_OBJECT_CLASS (mct_user_controls_parent_class)->finalize (object);
} }
@ -659,7 +663,13 @@ mct_user_controls_dispose (GObject *object)
{ {
MctUserControls *self = (MctUserControls *)object; MctUserControls *self = (MctUserControls *)object;
flush_update_blacklisted_apps (self); /* Since GTK calls g_object_run_dispose(), dispose() may be called multiple
* times. We definitely want to save any unsaved changes, but don’t need to
* do it multiple times, and after the first g_object_run_dispose() call,
* none of our child widgets are still around to extract data from anyway. */
if (!self->flushed_on_dispose)
flush_update_blacklisted_apps (self);
self->flushed_on_dispose = TRUE;
G_OBJECT_CLASS (mct_user_controls_parent_class)->dispose (object); G_OBJECT_CLASS (mct_user_controls_parent_class)->dispose (object);
} }

2
malcontent-control/user-controls.ui
View File

@ -527,7 +527,7 @@
<object class="MctRestrictApplicationsDialog" id="restrict_applications_dialog"> <object class="MctRestrictApplicationsDialog" id="restrict_applications_dialog">
<property name="visible">False</property> <property name="visible">False</property>
<property name="modal">True</property> <property name="modal">True</property>
<property name="destroy-with-parent">True</property> <property name="destroy-with-parent">False</property>
<property name="use-header-bar">1</property> <property name="use-header-bar">1</property>
<signal name="delete-event" handler="on_restrict_applications_dialog_delete_event_cb" /> <signal name="delete-event" handler="on_restrict_applications_dialog_delete_event_cb" />
<signal name="response" handler="on_restrict_applications_dialog_response_cb" /> <signal name="response" handler="on_restrict_applications_dialog_response_cb" />