| From e47337aa12a371cded61aefee052a808d32e0d64 Mon Sep 17 00:00:00 2001 |
| From: Gerd Hoffmann <kraxel@redhat.com> |
| Date: Mon, 9 Apr 2018 13:27:36 +0200 |
| Subject: [PATCH 02/10] vga: fix region calculation |
| |
| RH-Author: Gerd Hoffmann <kraxel@redhat.com> |
| Message-id: <20180409132736.24598-3-kraxel@redhat.com> |
| Patchwork-id: 79512 |
| O-Subject: [RHEL-7.5 qemu-kvm PATCH 2/2] vga: fix region calculation |
| Bugzilla: 1553670 |
| RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> |
| RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> |
| RH-Acked-by: John Snow <jsnow@redhat.com> |
| |
| Typically the scanline length and the line offset are identical. But |
| in case they are not our calculation for region_end is incorrect. Using |
| line_offset is fine for all scanlines, except the last one where we have |
| to use the actual scanline length. |
| |
| Fixes: CVE-2018-7550 |
| Reported-by: Ross Lagerwall <ross.lagerwall@citrix.com> |
| Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> |
| Reviewed-by: Prasad J Pandit <pjp@fedoraproject.org> |
| Tested-by: Ross Lagerwall <ross.lagerwall@citrix.com> |
| Message-id: 20180309143704.13420-1-kraxel@redhat.com |
| (cherry picked from commit 7cdc61becd095b64a786b2625f321624e7111f3d) |
| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| hw/display/vga.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| diff --git a/hw/display/vga.c b/hw/display/vga.c |
| index 8e6c6d6..9270a75 100644 |
| |
| |
| @@ -1535,6 +1535,8 @@ static void vga_draw_graphic(VGACommonState *s, int full_update) |
| |
| region_start = (s->start_addr * 4); |
| region_end = region_start + (ram_addr_t)s->line_offset * height; |
| + region_end += width * s->get_bpp(s) / 8; /* scanline length */ |
| + region_end -= s->line_offset; |
| if (region_end > s->vbe_size) { |
| /* wraps around (can happen with cirrus vbe modes) */ |
| region_start = 0; |
| -- |
| 1.8.3.1 |
| |