Automatic merge from submit-queue
Allow webhook authorizer to use SubjectAccessReviewInterface
Refactors the authorization webhook to be able to be fed a kubeconfig file or a SubjectAccessReviewsInterface
Added tests to exercise retry logic, and ensure the correct serialized version is sent to the remote webhook (I also made sure the new tests passed on the current webhook impl in master)
c.f. https://github.com/kubernetes/kubernetes/pull/32547
c.f. https://github.com/kubernetes/kubernetes/pull/32518
Automatic merge from submit-queue
Allow anonymous API server access, decorate authenticated users with system:authenticated group
When writing authorization policy, it is often necessary to allow certain actions to any authenticated user. For example, creating a service or configmap, and granting read access to all users
It is also frequently necessary to allow actions to any unauthenticated user. For example, fetching discovery APIs might be part of an authentication process, and therefore need to be able to be read without access to authentication credentials.
This PR:
* Adds an option to allow anonymous requests to the secured API port. If enabled, requests to the secure port that are not rejected by other configured authentication methods are treated as anonymous requests, and given a username of `system:anonymous` and a group of `system:unauthenticated`. Note: this should only be used with an `--authorization-mode` other than `AlwaysAllow`
* Decorates user.Info returned from configured authenticators with the group `system:authenticated`.
This is related to defining a default set of roles and bindings for RBAC (https://github.com/kubernetes/features/issues/2). The bootstrap policy should allow all users (anonymous or authenticated) to request the discovery APIs.
```release-note
kube-apiserver learned the '--anonymous-auth' flag, which defaults to true. When enabled, requests to the secure port that are not rejected by other configured authentication methods are treated as anonymous requests, and given a username of 'system:anonymous' and a group of 'system:unauthenticated'.
Authenticated users are decorated with a 'system:authenticated' group.
NOTE: anonymous access is enabled by default. If you rely on authentication alone to authorize access, change to use an authorization mode other than AlwaysAllow, or or set '--anonymous-auth=false'.
```
c.f. https://github.com/kubernetes/kubernetes/issues/29177#issuecomment-244191596
Allow the group claim to be a single string instead of an array of
strings. This means the following claim
{
"role": "admin"
}
Will be mapped to the groups
["admin"]
Automatic merge from submit-queue
Refactor cert utils into one pkg, add funcs from bootkube for kubeadm to use
**What this PR does / why we need it**:
We have ended-up with rather incomplete and fragmented collection of utils for handling certificates. It may be worse to consider using `cfssl` for doing all of these things, but for now there is some functionality that we need in `kubeadm` that we can borrow from bootkube. It makes sense to move the utils from bookube into core, as discussed in #31221.
**Special notes for your reviewer**: I've taken the opportunity to review names of existing funcs and tried to make some improvements in that area (with help from @peterbourgon).
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue
Allow secure access to apiserver from Admission Controllers
* Allow options.InsecurePort to be set to 0 to switch off insecure access
* In NewSelfClient, Set the TLSClientConfig to the cert and key files
if InsecurePort is switched off
* Mint a bearer token that allows the client(s) created in NewSelfClient
to talk to the api server
* Add a new authenticator that checks for this specific bearer token
Fixes#13598
* Allow options.InsecurePort to be set to 0 to switch off insecure access
* In NewSelfClient, Set the TLSClientConfig to the cert and key files
if InsecurePort is switched off
* Mint a bearer token that allows the client(s) created in NewSelfClient
to talk to the api server
* Add a new authenticator that checks for this specific bearer token
Fixes#13598
Automatic merge from submit-queue
plugin/pkg: add ericchiang to owners for OpenID Connect plugins
On the CoreOS side I'm taking over these components.
@erictune has suggested `pkg/registry/{cluster}role{binding}s/OWNERS` as well but I'd feel more comfortable as a reviewer for those specific parts of RBAC for a couple more cycles since @liggitt and @deads2k have had way more experience in the registry code.
Beyond that the only existing OWNERS files for auth are `pkg/auth/OWNERS` and `plugin/pkg/auth/OWNERS` both of which include @liggitt and @erictune. There's also nothing in the `plugin/pkg/client` path. I'm a little unclear on the implications for future PRs that are assigned to me (e.g. webhook or RBAC reviews).
cc @kubernetes/sig-auth
This changes clientcmd to skip the default cluster, but preserves the
behavior in kubectl. This prevents the possibility of an administrator
misconfiguration in kubelet or other server component from allowing a
third party who can bind to 8080 on that host from potentially
impersonating an API server and gaining root access.
Automatic merge from submit-queue
oidc authentication plugin: don't trim issuer URLs with trailing slashes
The issuer URL passed to the plugin must identically match the issuer
URL returned by OpenID Connect discovery. However, the plugin currently
trims all trailing slashes from issuer URLs, causing a mismatch. Since
the go-oidc client already handles this case correctly, don't trim the
path.
Closes#29749
cc @hanikesn @kubernetes/sig-auth
The issuer URL passed to the plugin must identically match the issuer
URL returned by OpenID Connect discovery. However, the plugin currently
trims all trailing slashes from issuer URLs, causing a mismatch. Since
the go-oidc client already handles this case correctly, don't trim the
path.
Automatic merge from submit-queue
Return (bool, error) in Authorizer.Authorize()
Before this change, Authorize() method was just returning an error, regardless of whether the user is unauthorized or whether there is some other unrelated error. Returning boolean with information about user authorization and error (which should be unrelated to the authorization) separately will make it easier to debug.
Fixes#27974
Before this change, Authorize() method was just returning an error,
regardless of whether the user is unauthorized or whether there
is some other unrelated error. Returning boolean with information
about user authorization and error (which should be unrelated to
the authorization) separately will make it easier to debug.
Fixes#27974
Automatic merge from submit-queue
getting emailAddress from TLS cert
Kubernetes if using TLS cert to perform authentication will use the CommonName field of the cert as the authenticating user. In https://github.com/kubernetes/kubernetes/blob/master/plugin/pkg/auth/authenticator/request/x509/x509.go#L106, alternative methods are defined to use emailAddress or DNSName as the authenticating user. The method that uses the emailAddress is not comprehensive as this information can be encoded in different places of the certificate. This PR fixes this.
Automatic merge from submit-queue
oidc auth plugin: don't hard fail if provider is unavailable
When using OpenID Connect authentication, don't cause the API
server to fail if the provider is unavailable. This allows
installations to run OpenID Connect providers after starting the
API server, a common case when the provider is running on the
cluster itself.
Errors are now deferred to the authenticate method.
cc @sym3tri @erictune @aaronlevy @kubernetes/sig-auth
