| From e65294157d4b69393b3f819c99f4f647452b48e3 Mon Sep 17 00:00:00 2001 |
| From: Gerd Hoffmann <kraxel@redhat.com> |
| Date: Mon, 28 Aug 2017 14:33:07 +0200 |
| Subject: [PATCH] vga: fix display update region calculation (split screen) |
| |
| vga display update mis-calculated the region for the dirty bitmap |
| snapshot in case split screen mode is used. This can trigger an |
| assert in cpu_physical_memory_snapshot_get_dirty(). |
| |
| Impact: DoS for privileged guest users. |
| |
| Fixes: CVE-2017-13673 |
| Fixes: fec5e8c92becad223df9d972770522f64aafdb72 |
| Cc: P J P <ppandit@redhat.com> |
| Reported-by: David Buchanan <d@vidbuchanan.co.uk> |
| Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> |
| Message-id: 20170828123307.15392-1-kraxel@redhat.com |
| |
| Upstream-Status: Backport |
| [https://git.qemu.org/?p=qemu.git;a=commit;h=e65294157d4b69393b3f819c99f4f647452b48e3] |
| |
| CVE: CVE-2017-13673 |
| |
| Signed-off-by: Yi Zhao <yi.zhao@windriver.com> |
| --- |
| hw/display/vga.c | 10 ++++++++-- |
| 1 file changed, 8 insertions(+), 2 deletions(-) |
| |
| diff --git a/hw/display/vga.c b/hw/display/vga.c |
| index 3433102..ad7a465 100644 |
| --- a/hw/display/vga.c |
| +++ b/hw/display/vga.c |
| @@ -1628,9 +1628,15 @@ static void vga_draw_graphic(VGACommonState *s, int full_update) |
| y1 = 0; |
| |
| if (!full_update) { |
| + ram_addr_t region_start = addr1; |
| + ram_addr_t region_end = addr1 + line_offset * height; |
| vga_sync_dirty_bitmap(s); |
| - snap = memory_region_snapshot_and_clear_dirty(&s->vram, addr1, |
| - line_offset * height, |
| + if (s->line_compare < height) { |
| + /* split screen mode */ |
| + region_start = 0; |
| + } |
| + snap = memory_region_snapshot_and_clear_dirty(&s->vram, region_start, |
| + region_end - region_start, |
| DIRTY_MEMORY_VGA); |
| } |
| |
| -- |
| 2.7.4 |
| |