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From 8c2d53ffb72c574d0c81e2c86115a18598e66c65 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 22 Feb 2017 12:36:26 +0100
Subject: [PATCH 08/24] vnc: fix overflow in vnc_update_stats
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
Message-id: <1487766986-6329-9-git-send-email-kraxel@redhat.com>
Patchwork-id: 73975
O-Subject: [RHEL-7.4 qemu-kvm PATCH 8/8] vnc: fix overflow in vnc_update_stats
Bugzilla: 1377977
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Marc-André Lureau <mlureau@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

Commit "bea60dd ui/vnc: fix potential memory corruption issues" is
incomplete.  vnc_update_stats must calculate width and height the same
way vnc_refresh_server_surface does it, to make sure we don't use width
and height values larger than the qemu vnc server can handle.

Commit "e22492d ui/vnc: disable adaptive update calculations if not
needed" masks the issue in the default configuration.  It triggers only
in case the "lossy" option is set to "on" (default is "off").

Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 1485248428-575-1-git-send-email-kraxel@redhat.com
(cherry picked from commit eebe0b7905642a986cbce7406d6ab7bf78f3e210)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 ui/vnc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index d0ada7e..b68918e 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2581,8 +2581,10 @@ static int vnc_refresh_lossy_rect(VncDisplay *vd, int x, int y)
 
 static int vnc_update_stats(VncDisplay *vd,  struct timeval * tv)
 {
-    int width = pixman_image_get_width(vd->guest.fb);
-    int height = pixman_image_get_height(vd->guest.fb);
+    int width = MIN(pixman_image_get_width(vd->guest.fb),
+                    pixman_image_get_width(vd->server));
+    int height = MIN(pixman_image_get_height(vd->guest.fb),
+                     pixman_image_get_height(vd->server));
     int x, y;
     struct timeval res;
     int has_dirty = 0;
-- 
1.8.3.1