Velero vulnerable to file path traversal when extracting from backup's tarball

### Impact _What kind of vulnerability is it? Who is impacted?_ If the attacker compromises the backup's object storage backend and uploads a malicious backup tarball including file names like the following: * ../../../tmp/escape_1 -> file created at /tmp/escape_1 * ../../../../../../../../tmp/escape_2 -> file created at /tmp/escape_2 * ../../../tmp/cron_poc -> would be /etc/cron.d/backdoor in real attack * ../../../tmp/ssh_poc -> would be ~/.ssh/authorized_keys * ../../../tmp/kubeconfig_poc -> would be ~/.kube/config

It's possible that extracting files from the tarball during restore can overwrite sensitive files in the Velero pod filesystem.

### Patches _Has the problem been patched? What versions should users upgrade to?_

By far, there is no patch yet. We are working on the main branch, then cherry-pick to the release-1.18 for v1.18.1 patch.

### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_

There is no workaround, but the good news is that keeping your OSS safe will prevent the vulnerability.