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authorLaszlo Ersek <lersek@redhat.com>2012-03-20 11:22:48 +0100
committerLuiz Capitulino <lcapitulino@redhat.com>2012-03-27 09:11:00 -0300
commitf24582d6ad8a080e008974c000bf0ae635d036ac (patch)
tree8724e20f9af9e8c9e6c8e3e90b2e94fb30a51d98
parent8a22565b7c2d1920b02b94e7a8021c65895a3a22 (diff)
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 <lersek@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
-rw-r--r--qapi/qmp-output-visitor.c8
1 files changed, 5 insertions, 3 deletions
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);
}