From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44542) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fV5gk-0000CC-5V for qemu-devel@nongnu.org; Mon, 18 Jun 2018 21:44:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fV5gg-0007fe-Qc for qemu-devel@nongnu.org; Mon, 18 Jun 2018 21:44:06 -0400 Sender: fluxion From: Michael Roth Date: Mon, 18 Jun 2018 20:43:11 -0500 Message-Id: <20180619014319.28272-106-mdroth@linux.vnet.ibm.com> In-Reply-To: <20180619014319.28272-1-mdroth@linux.vnet.ibm.com> References: <20180619014319.28272-1-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 105/113] vga: fix region calculation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Gerd Hoffmann From: Gerd Hoffmann 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 Signed-off-by: Gerd Hoffmann Reviewed-by: Prasad J Pandit Tested-by: Ross Lagerwall Message-id: 20180309143704.13420-1-kraxel@redhat.com (cherry picked from commit 7cdc61becd095b64a786b2625f321624e7111f3d) Signed-off-by: Michael Roth --- hw/display/vga.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/display/vga.c b/hw/display/vga.c index d150a3a3eb..1fa66d597d 100644 --- a/hw/display/vga.c +++ b/hw/display/vga.c @@ -1489,6 +1489,8 @@ 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; -- 2.11.0