Comment 10 for bug 1524274
Revision history for this message
| Matthew Booth (mbooth-9) wrote Re: Unprivileged api user can access host data using instance snapshot | #10 |
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0e1f616
(Get the code!)
The impact description isn't quite right, yet. The process which reads host data is executed directly by nova. It runs as the nova user, except for the lvm backend, which runs as root. libvirt/kvm is not involved, which means libvirt confinement isn't a protection here. As discussed above, use_cow_images = False is only relevant to filesystem storage (local/nfs).
How about:
Matthew Booth from Red Hat reported a vulnerability in Nova instance snapshot. By overwriting the disk inside an instance with a malicious image and requesting a snapshot, an authenticated user would be able to read an arbitrary file from the compute host. Note that the host file needs to be readable by the nova user to be exposed except when using lvm for instance storage, when all files readable by root are exposed. Only setups using libvirt to spawn instances are vulnerable. Of these, setups which use filesystem storage, and do not set "use_cow_images = False" in Nova configuration are not affected. Setups which use ceph, lvm, or ploop for instance storage, and setups which use filesystem storage with "use_cow_images = False" are all affected.