ACL permissions for the search endpoints are done in three passes. The
first (the `sufficientSearchPerms` method) is for performance and coarsely
rejects requests based on the passed-in context parameter if the user has no
permissions to any object in that context. The second (the
`filteredSearchContexts` method) filters out contexts based on whether the user
has permissions either to the requested namespace or again by context (to catch
the "all" context). Finally, when iterating over the objects available, we do
the usual filtering in the iterator.
Internal testing found several bugs in this filtering:
* CSI plugins can be searched by any authenticated user.
* Variables can be searched if the user has `job:read` permissions to the
variable's namespace instead of `variable:list`.
* Variables cannot be searched by wildcard namespace.
This is an information leak of the plugin names and variable paths, which we
don't consider to be privileged information but intended to protect anyways.
This changeset fixes these bugs by ensuring CSI plugins are filtered in the 1st
and 2nd pass ACL filters, and changes variables to check `variable:list` in the
2nd pass filter unless the wildcard namespace is passed (at which point we'll
fallback to filtering in the iterator).
Fixes: CVE-2023-3300
Fixes: #17906