AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

vhost: block speculation of translated descriptors

Browse Source 
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>
This commit is contained in:
Michael S. Tsirkin 2019-09-08 07:04:08 -04:00
parent cf8f169670
commit a89db445fb
1 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/vhost/vhost.c
View File

@ -2071,8 +2071,10 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
_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;