From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753547AbcD0VHt (ORCPT ); Wed, 27 Apr 2016 17:07:49 -0400 Received: from mga02.intel.com ([134.134.136.20]:11483 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752392AbcD0VHs (ORCPT ); Wed, 27 Apr 2016 17:07:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,543,1455004800"; d="scan'208";a="967914341" From: Ashutosh Dixit To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, security@kernel.org Cc: Sudeep Dutt , Ashutosh Dixit , Pengfei Wang Subject: [PATCH char-misc-linus] misc: mic: Fix for double fetch security bug in VOP driver Date: Wed, 27 Apr 2016 14:36:05 -0700 Message-Id: <7cd1b13eec80c462e97ba75f658611ff677da359.1461792580.git.ashutosh.dixit@intel.com> X-Mailer: git-send-email 2.0.0.rc3.2.g998f840 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The MIC VOP driver does two successive reads from user space to read a variable length data structure. Kernel memory corruption can result if the data structure changes between the two reads. This patch disallows the chance of this happening. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116651 Reported by: Pengfei Wang Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit --- drivers/misc/mic/vop/vop_vringh.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c index e94c7fb..88e4523 100644 --- a/drivers/misc/mic/vop/vop_vringh.c +++ b/drivers/misc/mic/vop/vop_vringh.c @@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg) ret = -EFAULT; goto free_ret; } + /* Ensure desc has not changed between the two reads */ + if (memcmp(&dd, dd_config, sizeof(dd))) { + ret = -EINVAL; + goto free_ret; + } mutex_lock(&vdev->vdev_mutex); mutex_lock(&vi->vop_mutex); ret = vop_virtio_add_device(vdev, dd_config); -- 2.0.0.rc3.2.g998f840