Typically the scanline length and the line offset are identical. But
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-<to-be-filled>
Cc: P J P <ppan...@redhat.com>
Cc: Ross Lagerwall <ross.lagerw...@citrix.com>
Signed-off-by: Gerd Hoffmann <kra...@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 28f298b342..72181330b8 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -1483,6 +1483,8 @@ 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;
--
2.9.3
