On Thu, Nov 01, 2018 at 04:00:23PM -0700, Kees Cook wrote:
> On Thu, Nov 1, 2018 at 2:19 PM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
> > The following changes since commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d:
> >
> > Linux 4.19 (2018-10-22 07:37:37 +0100)
> >
> > are available in the Git repository at:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git tags/for_linus
> >
> > for you to fetch changes up to 79f800b2e76923cd8ce0aa659cb5c019d9643bc9:
> >
> > MAINTAINERS: remove reference to bogus vsock file (2018-10-24 21:16:14 -0400)
> >
> > ----------------------------------------------------------------
> > virtio, vhost: fixes, tweaks
> >
> > virtio balloon page hinting support
> > vhost scsi control queue
> >
> > misc fixes.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> >
> > ----------------------------------------------------------------
> > Bijan Mottahedeh (3):
> > vhost/scsi: Respond to control queue operations
>
> +static void
> +vhost_scsi_send_tmf_resp(struct vhost_scsi *vs,
> + struct vhost_virtqueue *vq,
> + int head, unsigned int out)
> +{
> + struct virtio_scsi_ctrl_tmf_resp __user *resp;
> + struct virtio_scsi_ctrl_tmf_resp rsp;
> + int ret;
> +
> + pr_debug("%s\n", __func__);
> + memset(&rsp, 0, sizeof(rsp));
> + rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED;
> + resp = vq->iov[out].iov_base;
> + ret = __copy_to_user(resp, &rsp, sizeof(rsp));
>
> Is it actually safe to trust that iov_base has passed an earlier
> access_ok() check here? Why not just use copy_to_user() instead?
>
> -Kees
I am not sure copy_to_user will do the right thing here, because all
this runs in context of a kernel thread. We do need access_ok which
takes place way earlier in context of the task.
Another reason it is safe is because the address is not
coming from userspace at all.
> > vhost/scsi: Extract common handling code from control queue handler
> > vhost/scsi: Use common handling code in request queue handler
> >
> > Greg Edwards (1):
> > vhost/scsi: truncate T10 PI iov_iter to prot_bytes
> >
> > Lénaïc Huard (1):
> > kvm_config: add CONFIG_VIRTIO_MENU
> >
> > Stefan Hajnoczi (1):
> > MAINTAINERS: remove reference to bogus vsock file
> >
> > Wei Wang (3):
> > virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
> > mm/page_poison: expose page_poisoning_enabled to kernel modules
> > virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON
> >
> > MAINTAINERS | 1 -
> > drivers/vhost/scsi.c | 426 ++++++++++++++++++++++++++++--------
> > drivers/virtio/virtio_balloon.c | 380 +++++++++++++++++++++++++++++---
> > include/uapi/linux/virtio_balloon.h | 8 +
> > kernel/configs/kvm_guest.config | 1 +
> > mm/page_poison.c | 6 +
> > 6 files changed, 688 insertions(+), 134 deletions(-)
>
>
>
> --
> Kees Cook
