From 8f63265efeb6f92e63f7e749cb26131b68b20df7 Mon Sep 17 00:00:00 2001 From: Li Qiang Date: Mon, 13 Feb 2017 15:22:15 +0000 Subject: [PATCH] cirrus: fix oob access issue (CVE-2017-2615) When doing bitblt copy in backward mode, we should minus the blt width first just like the adding in the forward mode. This can avoid the oob access of the front of vga's vram. This is XSA-208. upstream-commit-id: 62d4c6bd5263bb8413a06c80144fc678df6dfb64 Signed-off-by: Li Qiang { kraxel: with backward blits (negative pitch) addr is the topmost address, so check it as-is against vram size ] Cc: qemu-stable@nongnu.org Cc: P J P Cc: Laszlo Ersek Cc: Paolo Bonzini Cc: Wolfgang Bumiller Fixes: d3532a0db02296e687711b8cdc7791924efccea0 (CVE-2014-8106) Signed-off-by: Gerd Hoffmann Message-id: 1485938101-26602-1-git-send-email-kraxel@redhat.com Reviewed-by: Laszlo Ersek Signed-off-by: Stefano Stabellini --- tools/qemu-xen/hw/display/cirrus_vga.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tools/qemu-xen/hw/display/cirrus_vga.c b/tools/qemu-xen/hw/display/cirrus_vga.c index 5198037..7bf3707 100644 --- a/tools/qemu-xen/hw/display/cirrus_vga.c +++ b/tools/qemu-xen/hw/display/cirrus_vga.c @@ -272,10 +272,9 @@ static bool blit_region_is_unsafe(struct CirrusVGAState *s, { if (pitch < 0) { int64_t min = addr - + ((int64_t)s->cirrus_blt_height-1) * pitch; - int32_t max = addr - + s->cirrus_blt_width; - if (min < 0 || max >= s->vga.vram_size) { + + ((int64_t)s->cirrus_blt_height - 1) * pitch + - s->cirrus_blt_width; + if (min < -1 || addr >= s->vga.vram_size) { return true; } } else { -- 2.1.4