From: Prasad J Pandit <pjp@fedoraproject.org>

Date: Thu, 25 Apr 2019 12:05:34 +0530

Subject: [PATCH] qxl: check release info object

When releasing spice resources in release_resource() routine,

if release info object 'ext.info' is null, it leads to null

pointer dereference. Add check to avoid it.

Reported-by: Bugs SysSec <bugs-syssec@rub.de>

Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>

Message-id: 20190425063534.32747-1-ppandit@redhat.com

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

(cherry picked from commit d52680fc932efb8a2f334cc6993e705ed1e31e99)

---

 hw/display/qxl.c | 3 +++

 1 file changed, 3 insertions(+)

diff --git a/hw/display/qxl.c b/hw/display/qxl.c

index c8ce5781e0..632923add2 100644

--- a/hw/display/qxl.c

+++ b/hw/display/qxl.c

@@ -777,6 +777,9 @@ static void interface_release_resource(QXLInstance *sin,

     QXLReleaseRing *ring;

     uint64_t *item, id;

+    if (!ext.info) {

+        return;

+    }

     if (ext.group_id == MEMSLOT_GROUP_HOST) {

         /* host group -> vga mode update request */

         QXLCommandExt *cmdext = (void *)(intptr_t)(ext.info->id);