From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56492) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etq2G-00077z-JQ for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1etq2D-0002Ou-Fz for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:20 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38230 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1etq2D-0002Om-Br for qemu-devel@nongnu.org; Thu, 08 Mar 2018 02:32:17 -0500 From: Gerd Hoffmann Date: Thu, 8 Mar 2018 08:31:59 +0100 Message-Id: <20180308073159.1068-1-kraxel@redhat.com> Subject: [Qemu-devel] [PATCH] vga: fix region calculation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Gerd Hoffmann , P J P , Ross Lagerwall 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- Cc: P J P Cc: Ross Lagerwall Signed-off-by: Gerd Hoffmann --- 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