Commit 82dc4afd authored Apr 27, 2016 by Ashutosh Dixit Committed by Greg Kroah-Hartman Apr 27, 2016

misc: mic: Fix for double fetch security bug in VOP driver

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 <wpengfeinudt@gmail.com>
Reviewed-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c3b46c73

drivers/misc/mic/vop/vop_vringh.c

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -945,6 +945,11 @@ static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
	ret = -EFAULT;		ret = -EFAULT;
	goto free_ret;		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(&vdev->vdev_mutex);
	mutex_lock(&vi->vop_mutex);		mutex_lock(&vi->vop_mutex);
	ret = vop_virtio_add_device(vdev, dd_config);		ret = vop_virtio_add_device(vdev, dd_config);