This change updates the impersonator to always authorize every
request instead of relying on the Kuberentes API server to perform
the check on the impersonated request. This protects us from
scenarios where we fail to correctly impersonate the user due to
some bug in our proxy logic. We still rely completely on the API
server to perform admission checks on the impersonated requests.
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonation proxy code to run as a
distinct service account that only has permission to impersonate
identities. Thus any future vulnerability that causes the
impersonation headers to be dropped will fail closed instead of
escalating to the concierge's default service account which has
significantly more permissions.
Signed-off-by: Monis Khan <mok@vmware.com>
WithImpersonation already deletes impersonation headers and has done
so since the early days:
https://github.com/kubernetes/kubernetes/pull/36769
ensureNoImpersonationHeaders will still reject any request that has
impersonation headers set so we will always fail closed.
Signed-off-by: Monis Khan <mok@vmware.com>
When anonymous authentication is disabled, the impersonation proxy
will no longer authenticate anonymous requests other than calls to
the token credential request API (this API is used to retrieve
credentials and thus must be accessed anonymously).
Signed-off-by: Benjamin A. Petersen <ben@benjaminapetersen.me>
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonator logic to pass through requests
that authenticated via a bearer token that asserts a UID. This
allows us to support service account tokens (as well as any other
form of token based authentication).
Signed-off-by: Monis Khan <mok@vmware.com>
This change updates the impersonator logic to use the delegated
authorizer for all non-rest verbs such as impersonate. This allows
it to correctly perform authorization checks for incoming requests
that set impersonation headers while not performing unnecessary
checks that are already handled by KAS.
The audit layer is enabled to track the original user who made the
request. This information is then included in a reserved extra
field original-user-info.impersonation-proxy.concierge.pinniped.dev
as a JSON blob.
Signed-off-by: Monis Khan <mok@vmware.com>
Instead of using the LongRunningFunc to determine if we can safely
use http2, follow the same logic as the aggregation proxy and only
use http2 when the request is not an upgrade.
Signed-off-by: Monis Khan <mok@vmware.com>
When the frontend connection to our proxy is closed, the proxy falls through to
a panic(), which means the HTTP handler goroutine is killed, so we were not
seeing this log statement.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
To make an impersonation request, first make a TokenCredentialRequest
to get a certificate. That cert will either be issued by the Kube
API server's CA or by a new CA specific to the impersonator. Either
way, you can then make a request to the impersonator and present
that client cert for auth and the impersonator will accept it and
make the impesonation call on your behalf.
The impersonator http handler now borrows some Kube library code
to handle request processing. This will allow us to more closely
mimic the behavior of a real API server, e.g. the client cert
auth will work exactly like the real API server.
Signed-off-by: Monis Khan <mok@vmware.com>
Also:
- Changed base64 encoding of impersonator bearer tokens to use
`base64.StdEncoding` to make it easier for users to manually
create a token using the unix `base64` command
- Test the headers which are and are not passed through to the Kube API
by the impersonator more carefully in the unit tests
- More WIP on concierge_impersonation_proxy_test.go
Signed-off-by: Margo Crawford <margaretc@vmware.com>
If someone has already set impersonation headers in their request, then
we should fail loudly so the client knows that its existing impersonation
headers will not work.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
- Watch a configmap to read the configuration of the impersonation
proxy and reconcile it.
- Implements "auto" mode by querying the API for control plane nodes.
- WIP: does not create a load balancer or proper TLS certificates yet.
Those will come in future commits.
Signed-off-by: Margo Crawford <margaretc@vmware.com>
I added that test helper to create an http.Request since I wanted to properly
initialize the http.Request's context.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
Monis Khan