From f24582d6ad8a080e008974c000bf0ae635d036ac Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Tue, 20 Mar 2012 11:22:48 +0100 Subject: qapi: fix double free in qmp_output_visitor_cleanup() Stack entries in QmpOutputVisitor are navigation links (weak references), except the bottom (ie. least recently added) entry, which owns the root QObject [1]. Make qmp_output_visitor_cleanup() drop the stack entries, then release the QObject tree by the root. Attempting to serialize an invalid enum inside a dictionary is an example for triggering the double free. [1] http://lists.nongnu.org/archive/html/qemu-devel/2012-03/msg03276.html Signed-off-by: Laszlo Ersek Signed-off-by: Luiz Capitulino --- qapi/qmp-output-visitor.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'qapi') diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c index e0697b0d0f..2bce9d5db1 100644 --- a/qapi/qmp-output-visitor.c +++ b/qapi/qmp-output-visitor.c @@ -199,14 +199,16 @@ void qmp_output_visitor_cleanup(QmpOutputVisitor *v) { QStackEntry *e, *tmp; + /* The bottom QStackEntry, if any, owns the root QObject. See the + * qmp_output_push_obj() invocations in qmp_output_add_obj(). */ + QObject *root = QTAILQ_EMPTY(&v->stack) ? NULL : qmp_output_first(v); + QTAILQ_FOREACH_SAFE(e, &v->stack, node, tmp) { QTAILQ_REMOVE(&v->stack, e, node); - if (e->value) { - qobject_decref(e->value); - } g_free(e); } + qobject_decref(root); g_free(v); } -- cgit v1.2.1