When native service discovery was added, we used the node secret as the auth
token. Once Workload Identity was added in Nomad 1.4.x we needed to use the
claim token for `template` blocks, and so we allowed valid claims to bypass the
ACL policy check to preserve the existing behavior. (Invalid claims are still
rejected, so this didn't widen any security boundary.)
In reworking authentication for 1.5.0, we unintentionally removed this
bypass. For WIs without a policy attached to their job, everything works as
expected because the resulting `acl.ACL` is nil. But once a policy is attached
to the job the `acl.ACL` is no longer nil and this causes permissions errors.
Fix the regression by adding back the bypass for valid claims. In future work,
we should strongly consider getting turning the implicit policies into real
`ACLPolicy` objects (even if not stored in state) so that we don't have these
kind of brittle exceptions to the auth code.
In order to support implicit ACL policies for tasks to get their own
secrets, each task would need to have its own ACL token. This would
add extra raft overhead as well as new garbage collection jobs for
cleaning up task-specific ACL tokens. Instead, Nomad will create a
workload Identity Claim for each task.
An Identity Claim is a JSON Web Token (JWT) signed by the server’s
private key and attached to an Allocation at the time a plan is
applied. The encoded JWT can be submitted as the X-Nomad-Token header
to replace ACL token secret IDs for the RPCs that support identity
claims.
Whenever a key is is added to a server’s keyring, it will use the key
as the seed for a Ed25519 public-private private keypair. That keypair
will be used for signing the JWT and for verifying the JWT.
This implementation is a ruthlessly minimal approach to support the
secure variables feature. When a JWT is verified, the allocation ID
will be checked against the Nomad state store, and non-existent or
terminal allocation IDs will cause the validation to be rejected. This
is sufficient to support the secure variables feature at launch
without requiring implementation of a background process to renew
soon-to-expire tokens.
This PR adds the 'choose' query parameter to the '/v1/service/<service>' endpoint.
The value of 'choose' is in the form '<number>|<key>', number is the number
of desired services and key is a value unique but consistent to the requester
(e.g. allocID).
Folks aren't really expected to use this API directly, but rather through consul-template
which will soon be getting a new helper function making use of this query parameter.
Example,
curl 'localhost:4646/v1/service/redis?choose=2|abc123'
Note: consul-templte v0.29.1 includes the necessary nomadServices functionality.
* services: add pagination and filter support to info RPC.
* cli: add filter flag to service info command.
* docs: add pagination and filter details to services info API.
* paginator: minor updates to comment and func signature.
In the same manner as the delete RPC, the list and read service
registration endpoints can be called either by external operators
or Nomad nodes. The latter occurs when a template is being
rendered which includes Nomad API template funcs. In this case,
the auth token is looked up as the node secret ID for auth.
hashicorp-copywrite[bot]