When a request is made to an RPC service that doesn't exist (for
example, a cross-region request from a newer version of Nomad to an
older version that doesn't implement the endpoint) the application
should return an empty list as well.
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
An ACL policy with a block without label generates unexpected results.
For example, a policy such as this:
```
namespace {
policy = "read"
}
```
Is applied to a namespace called `policy` instead of the documented
behaviour of applying it to the `default` namespace.
This happens because of the way HCL1 decodes blocks. Since it doesn't
know if a block is expected to have a label it applies the `key` tag to
the content of the block and, in the example above, the first key is
`policy`, so it sets that as the `namespace` block label.
Since this happens internally in the HCL decoder it's not possible to
detect the problem externally.
Fixing the problem inside the decoder is challenging because the JSON
and HCL parsers generate different ASTs that makes impossible to
differentiate between a JSON tree from an invalid HCL tree within the
decoder.
The fix in this commit consists of manually parsing the policy after
decoding to clear labels that were not set in the file. This allows the
validation rules to consistently catch and return any errors, no matter
if the policy is an invalid HCL or JSON.
When claiming a CSI volume, we need to ensure the CSI node plugin is running
before we send any CSI RPCs. This extends even to the controller publish RPC
because it requires the storage provider's "external node ID" for the
client. This primarily impacts client restarts but also is a problem if the node
plugin exits (and fingerprints) while the allocation that needs a CSI volume
claim is being placed.
Unfortunately there's no mapping of volume to plugin ID available in the
jobspec, so we don't have enough information to wait on plugins until we either
get the volume from the server or retrieve the plugin ID from data we've
persisted on the client.
If we always require getting the volume from the server before making the claim,
a client restart for disconnected clients will cause all the allocations that
need CSI volumes to fail. Even while connected, checking in with the server to
verify the volume's plugin before trying to make a claim RPC is inherently racy,
so we'll leave that case as-is and it will fail the claim if the node plugin
needed to support a newly-placed allocation is flapping such that the node
fingerprint is changing.
This changeset persists a minimum subset of data about the volume and its plugin
in the client state DB, and retrieves that data during the CSI hook's prerun to
avoid re-claiming and remounting the volume unnecessarily.
This changeset also updates the RPC handler to use the external node ID from the
claim whenever it is available.
Fixes: #13028
hc-github-team-nomad-core