If an untrusted device neogitates BLK_F_MQ but advertises a zero num_queues, the driver may end up trying to allocating zero size buffers where ZERO_SIZE_PTR is returned which may pass the checking against the NULL. This will lead unexpected results. Fixing this by using single queue if num_queues is zero. Cc: Paolo Bonzini <pbonzini at redhat.com> Cc: Stefan Hajnoczi <stefanha at redhat.com> Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/block/virtio_blk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index e574fbf5e6df..f130d12df4b9 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -498,7 +498,8 @@ static int init_vq(struct virtio_blk *vblk) err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, struct virtio_blk_config, num_queues, &num_vqs); - if (err) + /* We need at least on virtqueue */ + if (err || !num_vqs) num_vqs = 1; num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); -- 2.25.1
Stefano Garzarella
2021-Sep-13 07:48 UTC
[PATCH 1/9] virtio-blk: validate num_queues during probe
On Mon, Sep 13, 2021 at 01:53:45PM +0800, Jason Wang wrote:>If an untrusted device neogitates BLK_F_MQ but advertises a zero >num_queues, the driver may end up trying to allocating zero size >buffers where ZERO_SIZE_PTR is returned which may pass the checking >against the NULL. This will lead unexpected results. > >Fixing this by using single queue if num_queues is zero. > >Cc: Paolo Bonzini <pbonzini at redhat.com> >Cc: Stefan Hajnoczi <stefanha at redhat.com> >Signed-off-by: Jason Wang <jasowang at redhat.com> >--- > drivers/block/virtio_blk.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > >diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >index e574fbf5e6df..f130d12df4b9 100644 >--- a/drivers/block/virtio_blk.c >+++ b/drivers/block/virtio_blk.c >@@ -498,7 +498,8 @@ static int init_vq(struct virtio_blk *vblk) > err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, > struct virtio_blk_config, num_queues, > &num_vqs); >- if (err) >+ /* We need at least on virtqueue */s/on/one/ The rest LGTM. Stefano>+ if (err || !num_vqs) > num_vqs = 1; > > num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); >-- >2.25.1 > >_______________________________________________ >Virtualization mailing list >Virtualization at lists.linux-foundation.org >https://lists.linuxfoundation.org/mailman/listinfo/virtualization >
Stefan Hajnoczi
2021-Sep-13 12:05 UTC
[PATCH 1/9] virtio-blk: validate num_queues during probe
On Mon, Sep 13, 2021 at 01:53:45PM +0800, Jason Wang wrote:> If an untrusted device neogitates BLK_F_MQ but advertises a zero > num_queues, the driver may end up trying to allocating zero size > buffers where ZERO_SIZE_PTR is returned which may pass the checking > against the NULL. This will lead unexpected results. > > Fixing this by using single queue if num_queues is zero. > > Cc: Paolo Bonzini <pbonzini at redhat.com> > Cc: Stefan Hajnoczi <stefanha at redhat.com> > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/block/virtio_blk.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-)Reviewed-by: Stefan Hajnoczi <stefanha at redhat.com> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20210913/fb7d4947/attachment.sig>