From 2ff46c139a37bbe66732b9024daa771eff3e6c36 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Tue, 7 Feb 2017 10:07:52 +0100 Subject: [PATCH 09/11] cirrus: fix oob access issue (CVE-2017-2615) RH-Author: Gerd Hoffmann Message-id: <1486462072-32174-8-git-send-email-kraxel@redhat.com> Patchwork-id: 73565 O-Subject: [RHEL-7.4 qemu-kvm PATCH 7/7] cirrus: fix oob access issue (CVE-2017-2615) Bugzilla: 1418233 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Paolo Bonzini RH-Acked-by: Miroslav Rezanina From: Li Qiang 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. 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 (cherry picked from commit 62d4c6bd5263bb8413a06c80144fc678df6dfb64) Signed-off-by: Miroslav Rezanina --- hw/display/cirrus_vga.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c index 6aa29a3..e0e39ef 100644 --- a/hw/display/cirrus_vga.c +++ b/hw/display/cirrus_vga.c @@ -269,10 +269,9 @@ 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 { -- 1.8.3.1