On Tue, Sep 10, 2019 at 09:52:10AM +0800, Jason Wang wrote: > > On 2019/9/9 下午10:45, Michael S. Tsirkin wrote: > > On Mon, Sep 09, 2019 at 03:19:55PM +0800, Jason Wang wrote: > > > On 2019/9/8 下午7:05, Michael S. Tsirkin wrote: > > > > iovec addresses coming from vhost are assumed to be > > > > pre-validated, but in fact can be speculated to a value > > > > out of range. > > > > > > > > Userspace address are later validated with array_index_nospec so we can > > > > be sure kernel info does not leak through these addresses, but vhost > > > > must also not leak userspace info outside the allowed memory table to > > > > guests. > > > > > > > > Following the defence in depth principle, make sure > > > > the address is not validated out of node range. > > > > > > > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > > > --- > > > > drivers/vhost/vhost.c | 4 +++- > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > > > index 5dc174ac8cac..0ee375fb7145 100644 > > > > --- a/drivers/vhost/vhost.c > > > > +++ b/drivers/vhost/vhost.c > > > > @@ -2072,7 +2072,9 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, > > > > size = node->size - addr + node->start; > > > > _iov->iov_len = min((u64)len - s, size); > > > > _iov->iov_base = (void __user *)(unsigned long) > > > > - (node->userspace_addr + addr - node->start); > > > > + (node->userspace_addr + > > > > + array_index_nospec(addr - node->start, > > > > + node->size)); > > > > s += size; > > > > addr += size; > > > > ++ret; > > > > > > I've tried this on Kaby Lake smap off metadata acceleration off using > > > testpmd (virtio-user) + vhost_net. I don't see obvious performance > > > difference with TX PPS. > > > > > > Thanks > > Should I push this to Linus right now then? It's a security thing so > > maybe we better do it ASAP ... what's your opinion? > > > Yes, you can. > > Acked-by: Jason Wang <jasowang@xxxxxxxxxx> And should I include Tested-by: Jason Wang <jasowang@xxxxxxxxxx> ? > > > >
