Files
pinniped/internal/controller/authenticator/jwtcachefiller/jwtcachefiller.go
2024-06-11 09:39:48 -05:00

620 lines
22 KiB
Go

// Copyright 2020-2024 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package jwtcachefiller implements a controller for filling an authncache.Cache with each
// added/updated JWTAuthenticator.
package jwtcachefiller
import (
"context"
"crypto/x509"
"errors"
"fmt"
"net/http"
"net/url"
"reflect"
"strings"
"time"
coreosoidc "github.com/coreos/go-oidc/v3/oidc"
"github.com/go-jose/go-jose/v3"
"k8s.io/apimachinery/pkg/api/equality"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
utilerrors "k8s.io/apimachinery/pkg/util/errors"
"k8s.io/apiserver/pkg/apis/apiserver"
"k8s.io/apiserver/pkg/authentication/authenticator"
"k8s.io/apiserver/plugin/pkg/authenticator/token/oidc"
"k8s.io/klog/v2"
"k8s.io/utils/clock"
"k8s.io/utils/ptr"
authenticationv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/authentication/v1alpha1"
oidcapi "go.pinniped.dev/generated/latest/apis/supervisor/oidc"
conciergeclientset "go.pinniped.dev/generated/latest/client/concierge/clientset/versioned"
authinformers "go.pinniped.dev/generated/latest/client/concierge/informers/externalversions/authentication/v1alpha1"
pinnipedcontroller "go.pinniped.dev/internal/controller"
pinnipedauthenticator "go.pinniped.dev/internal/controller/authenticator"
"go.pinniped.dev/internal/controller/authenticator/authncache"
"go.pinniped.dev/internal/controller/conditionsutil"
"go.pinniped.dev/internal/controllerlib"
"go.pinniped.dev/internal/net/phttp"
"go.pinniped.dev/internal/plog"
)
const (
controllerName = "jwtcachefiller-controller"
typeReady = "Ready"
typeTLSConfigurationValid = "TLSConfigurationValid"
typeIssuerURLValid = "IssuerURLValid"
typeDiscoveryValid = "DiscoveryURLValid"
typeJWKSURLValid = "JWKSURLValid"
typeJWKSFetchValid = "JWKSFetchValid"
typeAuthenticatorValid = "AuthenticatorValid"
reasonSuccess = "Success"
reasonNotReady = "NotReady"
reasonUnableToValidate = "UnableToValidate"
reasonInvalidIssuerURL = "InvalidIssuerURL"
reasonInvalidIssuerURLScheme = "InvalidIssuerURLScheme"
reasonInvalidIssuerURLFragment = "InvalidIssuerURLContainsFragment"
reasonInvalidIssuerURLQueryParams = "InvalidIssuerURLContainsQueryParams"
reasonInvalidIssuerURLContainsWellKnownEndpoint = "InvalidIssuerURLContainsWellKnownEndpoint"
reasonInvalidProviderJWKSURL = "InvalidProviderJWKSURL"
reasonInvalidProviderJWKSURLScheme = "InvalidProviderJWKSURLScheme"
reasonInvalidTLSConfiguration = "InvalidTLSConfiguration"
reasonInvalidDiscoveryProbe = "InvalidDiscoveryProbe"
reasonInvalidAuthenticator = "InvalidAuthenticator"
reasonInvalidCouldNotFetchJWKS = "InvalidCouldNotFetchJWKS"
msgUnableToValidate = "unable to validate; see other conditions for details"
// These default values come from the way that the Supervisor issues and signs tokens. We make these
// the defaults for a JWTAuthenticator so that they can easily integrate with the Supervisor.
defaultUsernameClaim = oidcapi.IDTokenClaimUsername
defaultGroupsClaim = oidcapi.IDTokenClaimGroups
minimalJWTToTriggerJWKSFetch = "eyJhbGciOiJub25lIiwidHlwIjoiSldUIn0.e30."
)
type providerJSON struct {
JWKSURL string `json:"jwks_uri"`
}
// defaultSupportedSigningAlgos returns the default signing algos that this JWTAuthenticator
// supports (i.e., if none are supplied by the user).
func defaultSupportedSigningAlgos() []string {
return []string{
// RS256 is recommended by the OIDC spec and required, in some capacity. Since we want the
// JWTAuthenticator to be able to support many OIDC ID tokens out of the box, we include this
// algorithm by default.
string(jose.RS256),
// ES256 is what the Supervisor does, by default. We want integration with the JWTAuthenticator
// to be as seamless as possible, so we include this algorithm by default.
string(jose.ES256),
}
}
type tokenAuthenticatorCloser interface {
authenticator.Token
pinnipedauthenticator.Closer
}
type cachedJWTAuthenticator struct {
authenticator.Token
spec *authenticationv1alpha1.JWTAuthenticatorSpec
cancel context.CancelFunc
}
func (c *cachedJWTAuthenticator) Close() {
c.cancel()
}
var _ tokenAuthenticatorCloser = (*cachedJWTAuthenticator)(nil)
// New instantiates a new controllerlib.Controller which will populate the provided authncache.Cache.
func New(
cache *authncache.Cache,
client conciergeclientset.Interface,
jwtAuthenticators authinformers.JWTAuthenticatorInformer,
clock clock.Clock,
log plog.Logger,
) controllerlib.Controller {
return controllerlib.New(
controllerlib.Config{
Name: controllerName,
Syncer: &jwtCacheFillerController{
cache: cache,
client: client,
jwtAuthenticators: jwtAuthenticators,
clock: clock,
log: log.WithName(controllerName),
},
},
controllerlib.WithInformer(
jwtAuthenticators,
pinnipedcontroller.MatchAnythingFilter(nil), // nil parent func is fine because each event is distinct
controllerlib.InformerOption{},
),
)
}
type jwtCacheFillerController struct {
cache *authncache.Cache
jwtAuthenticators authinformers.JWTAuthenticatorInformer
client conciergeclientset.Interface
clock clock.Clock
log plog.Logger
}
// Sync implements controllerlib.Syncer.
func (c *jwtCacheFillerController) Sync(ctx controllerlib.Context) error {
obj, err := c.jwtAuthenticators.Lister().Get(ctx.Key.Name)
if err != nil && apierrors.IsNotFound(err) {
c.log.Info("Sync() found that the JWTAuthenticator does not exist yet or was deleted")
return nil
}
if err != nil {
return fmt.Errorf("failed to get JWTAuthenticator %s/%s: %w", ctx.Key.Namespace, ctx.Key.Name, err)
}
cacheKey := authncache.Key{
APIGroup: authenticationv1alpha1.GroupName,
Kind: "JWTAuthenticator",
Name: ctx.Key.Name,
}
// If this authenticator already exists, then only recreate it if is different from the desired
// authenticator. We don't want to be creating a new authenticator for every resync period.
//
// If we do need to recreate the authenticator, then make sure cancel the old one to avoid
// goroutine leaks.
if value := c.cache.Get(cacheKey); value != nil {
jwtAuthenticator := c.extractValueAsJWTAuthenticator(value)
if jwtAuthenticator != nil {
if reflect.DeepEqual(jwtAuthenticator.spec, &obj.Spec) {
c.log.WithValues("jwtAuthenticator", klog.KObj(obj), "issuer", obj.Spec.Issuer).Info("actual jwt authenticator and desired jwt authenticator are the same")
return nil
}
jwtAuthenticator.Close()
}
}
conditions := make([]*metav1.Condition, 0)
specCopy := obj.Spec.DeepCopy()
var errs []error
rootCAs, conditions, tlsOk := c.validateTLS(specCopy.TLS, conditions)
_, conditions, issuerOk := c.validateIssuer(specCopy.Issuer, conditions)
okSoFar := tlsOk && issuerOk
client := phttp.Default(rootCAs)
client.Timeout = 30 * time.Second // copied from Kube OIDC code
coreOSCtx := coreosoidc.ClientContext(context.Background(), client)
pJSON, provider, conditions, providerErr := c.validateProviderDiscovery(coreOSCtx, specCopy.Issuer, conditions, okSoFar)
errs = append(errs, providerErr)
okSoFar = okSoFar && providerErr == nil
jwksURL, conditions, jwksErr := c.validateProviderJWKSURL(provider, pJSON, conditions, okSoFar)
errs = append(errs, jwksErr)
okSoFar = okSoFar && jwksErr == nil
keySet, conditions, jwksFetchErr := c.validateJWKSFetch(coreOSCtx, jwksURL, conditions, okSoFar)
errs = append(errs, jwksFetchErr)
okSoFar = okSoFar && jwksFetchErr == nil
// Make a deep copy of the spec so we aren't storing pointers to something that the informer cache
// may mutate! We don't store status as status is derived from spec.
cachedAuthenticator, conditions, err := c.newCachedJWTAuthenticator(
client,
obj.Spec.DeepCopy(),
keySet,
conditions,
okSoFar)
errs = append(errs, err)
if !conditionsutil.HadErrorCondition(conditions) {
c.cache.Store(cacheKey, cachedAuthenticator)
c.log.Info("added new jwt authenticator", "jwtAuthenticator", klog.KObj(obj), "issuer", obj.Spec.Issuer)
}
err = c.updateStatus(ctx.Context, obj, conditions)
errs = append(errs, err)
// Sync loop errors:
// - Should not be configuration errors. Config errors a user must correct belong on the .Status
// object. The controller simply must wait for a user to correct before running again.
// - Other errors, such as networking errors, etc. are the types of errors that should return here
// and signal the controller to retry the sync loop. These may be corrected by machines.
return utilerrors.NewAggregate(errs)
}
func (c *jwtCacheFillerController) extractValueAsJWTAuthenticator(value authncache.Value) *cachedJWTAuthenticator {
jwtAuthenticator, ok := value.(*cachedJWTAuthenticator)
if !ok {
actualType := "<nil>"
if t := reflect.TypeOf(value); t != nil {
actualType = t.String()
}
c.log.WithValues("actualType", actualType).Info("wrong JWT authenticator type in cache")
return nil
}
return jwtAuthenticator
}
func (c *jwtCacheFillerController) validateTLS(tlsSpec *authenticationv1alpha1.TLSSpec, conditions []*metav1.Condition) (*x509.CertPool, []*metav1.Condition, bool) {
rootCAs, _, err := pinnipedcontroller.BuildCertPoolAuth(tlsSpec)
if err != nil {
msg := fmt.Sprintf("%s: %s", "invalid TLS configuration", err.Error())
conditions = append(conditions, &metav1.Condition{
Type: typeTLSConfigurationValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidTLSConfiguration,
Message: msg,
})
return rootCAs, conditions, false
}
msg := "successfully parsed specified CA bundle"
if rootCAs == nil {
msg = "no CA bundle specified"
}
conditions = append(conditions, &metav1.Condition{
Type: typeTLSConfigurationValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: msg,
})
return rootCAs, conditions, true
}
func (c *jwtCacheFillerController) validateIssuer(issuer string, conditions []*metav1.Condition) (*url.URL, []*metav1.Condition, bool) {
issuerURL, err := url.Parse(issuer)
if err != nil {
msg := fmt.Sprintf("%s: %s", "spec.issuer URL is invalid", err.Error())
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidIssuerURL,
Message: msg,
})
return nil, conditions, false
}
if issuerURL.Scheme != "https" {
msg := fmt.Sprintf("spec.issuer %s has invalid scheme, require 'https'", issuer)
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidIssuerURLScheme,
Message: msg,
})
return nil, conditions, false
}
if strings.HasSuffix(issuerURL.Path, "/.well-known/openid-configuration") {
msg := fmt.Sprintf("spec.issuer %s cannot include path '/.well-known/openid-configuration'", issuer)
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidIssuerURLContainsWellKnownEndpoint,
Message: msg,
})
return nil, conditions, false
}
if len(issuerURL.Query()) != 0 {
msg := fmt.Sprintf("spec.issuer %s cannot include query params", issuer)
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidIssuerURLQueryParams,
Message: msg,
})
return nil, conditions, false
}
if issuerURL.Fragment != "" {
msg := fmt.Sprintf("spec.issuer %s cannot include fragment", issuer)
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidIssuerURLFragment,
Message: msg,
})
return nil, conditions, false
}
conditions = append(conditions, &metav1.Condition{
Type: typeIssuerURLValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: "issuer is a valid URL",
})
return issuerURL, conditions, true
}
func (c *jwtCacheFillerController) validateProviderDiscovery(ctx context.Context, issuer string, conditions []*metav1.Condition, prereqOk bool) (*providerJSON, *coreosoidc.Provider, []*metav1.Condition, error) {
if !prereqOk {
conditions = append(conditions, &metav1.Condition{
Type: typeDiscoveryValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: msgUnableToValidate,
})
return nil, nil, conditions, nil
}
provider, err := coreosoidc.NewProvider(ctx, issuer)
pJSON := &providerJSON{}
if err != nil {
errText := "could not perform oidc discovery on provider issuer"
msg := fmt.Sprintf("%s: %s", errText, pinnipedcontroller.TruncateMostLongErr(err))
conditions = append(conditions, &metav1.Condition{
Type: typeDiscoveryValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidDiscoveryProbe,
Message: msg,
})
// resync err, may be machine or other types of non-config error
return nil, nil, conditions, fmt.Errorf("%s: %s", errText, err)
}
msg := "discovery performed successfully"
conditions = append(conditions, &metav1.Condition{
Type: typeDiscoveryValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: msg,
})
return pJSON, provider, conditions, nil
}
func (c *jwtCacheFillerController) validateProviderJWKSURL(provider *coreosoidc.Provider, pJSON *providerJSON, conditions []*metav1.Condition, prereqOk bool) (string, []*metav1.Condition, error) {
if provider == nil || pJSON == nil || !prereqOk {
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSURLValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: msgUnableToValidate,
})
return "", conditions, nil
}
// should be impossible because coreosoidc.NewProvider validates this, thus we can't write a test to get in this state (currently)
if err := provider.Claims(pJSON); err != nil {
errText := "could not get provider jwks_uri"
msg := fmt.Sprintf("%s: %s", errText, err.Error())
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidProviderJWKSURL,
Message: msg,
})
// resync err, the user may not be able to fix this via config, it may be the server may be misbehaving.
return pJSON.JWKSURL, conditions, fmt.Errorf("%s: %w", errText, err)
}
parsedJWKSURL, err := url.Parse(pJSON.JWKSURL)
if err != nil {
errText := "could not parse provider jwks_uri"
msg := fmt.Sprintf("%s: %s", errText, err.Error())
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidProviderJWKSURL,
Message: msg,
})
// resync err, the user may not be able to fix this via config, it may be the server may be misbehaving.
return pJSON.JWKSURL, conditions, fmt.Errorf("%s: %w", errText, err)
}
// spec asserts https is required. https://openid.net/specs/openid-connect-discovery-1_0.html
if parsedJWKSURL.Scheme != "https" {
msg := fmt.Sprintf("jwks_uri %s has invalid scheme, require 'https'", pJSON.JWKSURL)
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSURLValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidProviderJWKSURLScheme,
Message: msg,
})
return pJSON.JWKSURL, conditions, fmt.Errorf("%s", msg)
}
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSURLValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: "jwks_uri is a valid URL",
})
return pJSON.JWKSURL, conditions, nil
}
// validateJWKSFetch deliberately takes an unsigned JWT to trigger coreosoidc.NewRemoteKeySet to
// indirectly fetch the JWKS. This lets us report a status about the endpoint, even though
// we expect the verification checks to actually fail. This also pre-warms the cache of keys
// in the remote keyset object.
func (c *jwtCacheFillerController) validateJWKSFetch(ctx context.Context, jwksURL string, conditions []*metav1.Condition, prereqOk bool) (*coreosoidc.RemoteKeySet, []*metav1.Condition, error) {
if !prereqOk {
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSFetchValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: msgUnableToValidate,
})
return nil, conditions, nil
}
keySet := coreosoidc.NewRemoteKeySet(ctx, jwksURL)
// keySet.verifySignature calls functions which may error in a couple of ways that
// we will treat as success because we are really only concerned here that we could
// fetch the keys at all.
_, verifyWithKeySetErr := keySet.VerifySignature(ctx, minimalJWTToTriggerJWKSFetch)
if verifyWithKeySetErr == nil {
// No unit test.
// Since we hard-coded this token we expect there to always be a verification error.
// The purpose of this function is really to test if we can get the JWKS, not to actually validate a token.
// Therefore, we should never hit this path, nevertheless, lets handle just in case something unexpected happens.
errText := "jwks should not have verified unsigned jwt token"
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSFetchValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: errText,
})
return nil, conditions, errors.New(errText)
}
verifyErrString := verifyWithKeySetErr.Error()
// We need to fetch the keys. This is the main concern of this function.
if strings.HasPrefix(verifyErrString, "fetching keys") {
errText := "could not fetch keys"
msg := fmt.Sprintf("%s: %s", errText, verifyErrString)
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSFetchValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidCouldNotFetchJWKS,
Message: msg,
})
return nil, conditions, fmt.Errorf("%s: %w", errText, verifyWithKeySetErr)
}
// This error indicates success of this check. We only wanted to test if we could fetch, we aren't actually
// testing for valid signature verification.
if strings.Contains(verifyErrString, "failed to verify id token signature") {
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSFetchValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: "successfully fetched jwks",
})
return keySet, conditions, nil
}
// No unit tests, currently no way to reach this code path.
errText := "unexpected verification error while fetching jwks"
msg := fmt.Sprintf("%s: %s", errText, verifyErrString)
conditions = append(conditions, &metav1.Condition{
Type: typeJWKSFetchValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: msg,
})
return nil, conditions, fmt.Errorf("%s: %w", errText, verifyWithKeySetErr)
}
// newCachedJWTAuthenticator creates a jwt authenticator from the provided spec.
func (c *jwtCacheFillerController) newCachedJWTAuthenticator(client *http.Client, spec *authenticationv1alpha1.JWTAuthenticatorSpec, keySet *coreosoidc.RemoteKeySet, conditions []*metav1.Condition, prereqOk bool) (*cachedJWTAuthenticator, []*metav1.Condition, error) {
if !prereqOk {
conditions = append(conditions, &metav1.Condition{
Type: typeAuthenticatorValid,
Status: metav1.ConditionUnknown,
Reason: reasonUnableToValidate,
Message: msgUnableToValidate,
})
return nil, conditions, nil
}
usernameClaim := spec.Claims.Username
if usernameClaim == "" {
usernameClaim = defaultUsernameClaim
}
groupsClaim := spec.Claims.Groups
if groupsClaim == "" {
groupsClaim = defaultGroupsClaim
}
cancelCtx, cancel := context.WithCancel(context.Background())
oidcAuthenticator, err := oidc.New(cancelCtx, oidc.Options{
JWTAuthenticator: apiserver.JWTAuthenticator{
Issuer: apiserver.Issuer{
URL: spec.Issuer,
Audiences: []string{spec.Audience},
},
ClaimMappings: apiserver.ClaimMappings{
Username: apiserver.PrefixedClaimOrExpression{
Claim: usernameClaim,
Prefix: ptr.To(""),
},
Groups: apiserver.PrefixedClaimOrExpression{
Claim: groupsClaim,
Prefix: ptr.To(""),
},
},
},
KeySet: keySet,
SupportedSigningAlgs: defaultSupportedSigningAlgos(),
Client: client,
})
if err != nil {
// no unit test for this failure.
// it seems that our production code doesn't provide config knobs that would allow
// incorrect configuration of oidc.New(). We validate inputs before we get to this point
// and exit early if there are problems. In the future, if we allow more configuration,
// such as supported signing algorithm config, we may be able to test this.
errText := "could not initialize oidc authenticator"
msg := fmt.Sprintf("%s: %s", errText, err.Error())
conditions = append(conditions, &metav1.Condition{
Type: typeAuthenticatorValid,
Status: metav1.ConditionFalse,
Reason: reasonInvalidAuthenticator,
Message: msg,
})
cancel()
// resync err, lots of possible issues that may or may not be machine related
return nil, conditions, fmt.Errorf("%s: %w", errText, err)
}
msg := "authenticator initialized"
conditions = append(conditions, &metav1.Condition{
Type: typeAuthenticatorValid,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: msg,
})
return &cachedJWTAuthenticator{
Token: oidcAuthenticator,
spec: spec,
cancel: cancel,
}, conditions, nil
}
func (c *jwtCacheFillerController) updateStatus(
ctx context.Context,
original *authenticationv1alpha1.JWTAuthenticator,
conditions []*metav1.Condition,
) error {
updated := original.DeepCopy()
if conditionsutil.HadErrorCondition(conditions) {
updated.Status.Phase = authenticationv1alpha1.JWTAuthenticatorPhaseError
conditions = append(conditions, &metav1.Condition{
Type: typeReady,
Status: metav1.ConditionFalse,
Reason: reasonNotReady,
Message: "the JWTAuthenticator is not ready: see other conditions for details",
})
} else {
updated.Status.Phase = authenticationv1alpha1.JWTAuthenticatorPhaseReady
conditions = append(conditions, &metav1.Condition{
Type: typeReady,
Status: metav1.ConditionTrue,
Reason: reasonSuccess,
Message: "the JWTAuthenticator is ready",
})
}
_ = conditionsutil.MergeConditions(
conditions,
original.Generation,
&updated.Status.Conditions,
plog.New().WithName(controllerName),
metav1.NewTime(c.clock.Now()),
)
if equality.Semantic.DeepEqual(original, updated) {
return nil
}
_, err := c.client.AuthenticationV1alpha1().JWTAuthenticators().UpdateStatus(ctx, updated, metav1.UpdateOptions{})
return err
}