On Fri, Feb 17, 2017 at 10:26:51AM -0500, Keith Busch wrote:
> On Fri, Feb 17, 2017 at 01:59:41PM +0100, Christoph Hellwig wrote:
> > @@ -1789,7 +1789,8 @@ static void nvme_reset_work(struct work_struct *work)
> > if (result)
> > goto out;
> >
> > - if ((dev->ctrl.oacs & NVME_CTRL_OACS_SEC_SUPP) && !dev->ctrl.opal_dev) {
> > + kfree(dev->ctrl.opal_dev);
> > + if (dev->ctrl.oacs & NVME_CTRL_OACS_SEC_SUPP) {
> > dev->ctrl.opal_dev =
> > init_opal_dev(&dev->ctrl, &nvme_sec_submit);
> > }
>
> A couple things.
>
> This has a use-after-free in opal_unlock_from_suspend if the nvme
> device had an opal_dev before, but no longer support the capability
> after resume. So you'd want to set ctrl.opal_dev to NULL after the free.
>
> But we don't want to unconditionally free it anyway during resume
> since opal_unlock_from_suspend requires the exisiting opal_dev state
> information saved in the 'unlk_list'.
>
> Something like this instead:
>
> ---
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index ddc51ad..8fa6be9 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1789,13 +1789,17 @@ static void nvme_reset_work(struct work_struct *work)
> if (result)
> goto out;
>
> - if ((dev->ctrl.oacs & NVME_CTRL_OACS_SEC_SUPP) && !dev->ctrl.opal_dev) {
> - dev->ctrl.opal_dev =
> - init_opal_dev(&dev->ctrl, &nvme_sec_submit);
> + if (dev->ctrl.oacs & NVME_CTRL_OACS_SEC_SUPP)
> + if (was_suspend && dev->ctrl.opal_dev)
> + opal_unlock_from_suspend(dev->ctrl.opal_dev);
> + else if (!dev->ctrl.opal_dev)
> + dev->ctrl.opal_dev =
> + init_opal_dev(&dev->ctrl, &nvme_sec_submit);
> + } else {
> + kfree(dev->ctrl.opal_dev);
> + dev->ctrl.opal_dev = NULL;
Keith's comments made me realize something even deeper as well. Assuming the firmware
changed and we no longer support security commands we need to free the opal_dev structure
like we're doing but there is a possiblity that there were saved ranges in the structure
that we need to free as well. If the user had previously told the kernel to unlock 5
ranges coming out of a suspend there are 5 structures we need to free inside the opal_dev
before we free the opal dev. We'll need to re-introduce free_opal_dev() in the opal code
like we had a while back.
