From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43465) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cZIwn-00009b-Np for qemu-devel@nongnu.org; Thu, 02 Feb 2017 10:05:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cZIwh-0002rI-KZ for qemu-devel@nongnu.org; Thu, 02 Feb 2017 10:05:17 -0500 From: Gerd Hoffmann Date: Thu, 2 Feb 2017 16:05:07 +0100 Message-Id: <1486047907-26685-5-git-send-email-kraxel@redhat.com> In-Reply-To: <1486047907-26685-1-git-send-email-kraxel@redhat.com> References: <1486047907-26685-1-git-send-email-kraxel@redhat.com> Subject: [Qemu-devel] [PULL 4/4] cirrus: fix oob access issue (CVE-2017-2615) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Li Qiang , qemu-stable@nongnu.org, P J P , Laszlo Ersek , Paolo Bonzini , Wolfgang Bumiller , Gerd Hoffmann 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 --- 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 7db6409..16f27e8 100644 --- a/hw/display/cirrus_vga.c +++ b/hw/display/cirrus_vga.c @@ -274,10 +274,9 @@ 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