From: Michael S. Tsirkin mst@redhat.com
commit a89db445fbd7f1f8457b03759aa7343fa530ef6b upstream.
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@redhat.com Cc: stable@vger.kernel.org Acked-by: Jason Wang jasowang@redhat.com Tested-by: Jason Wang jasowang@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/vhost/vhost.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1954,8 +1954,10 @@ static int translate_desc(struct vhost_v _iov = iov + ret; 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); + _iov->iov_base = (void __user *) + ((unsigned long)node->userspace_addr + + array_index_nospec((unsigned long)(addr - node->start), + node->size)); s += size; addr += size; ++ret;