4.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ashutosh Dixit <[email protected]> commit 9bf292bfca94694a721449e3fd752493856710f6 upstream. 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 <[email protected]> Reviewed-by: Sudeep Dutt <[email protected]> Signed-off-by: Ashutosh Dixit <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/misc/mic/vop/vop_vringh.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/misc/mic/vop/vop_vringh.c +++ b/drivers/misc/mic/vop/vop_vringh.c @@ -950,6 +950,11 @@ static long vop_ioctl(struct file *f, un ret = -EINVAL; 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);
