/
authentication.go
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/
authentication.go
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/*
* Tencent is pleased to support the open source community by making TKEStack
* available.
*
* Copyright (C) 2012-2019 Tencent. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use
* this file except in compliance with the License. You may obtain a copy of the
* License at
*
* https://opensource.org/licenses/Apache-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
*/
package filter
import (
"errors"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/authentication/authenticator"
"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
"k8s.io/component-base/metrics"
"k8s.io/component-base/metrics/legacyregistry"
"net/http"
"strings"
"tkestack.io/tke/pkg/util/log"
)
const (
successLabel = "success"
failureLabel = "failure"
errorLabel = "error"
)
var (
authenticatedUserCounter = metrics.NewCounterVec(
&metrics.CounterOpts{
Name: "tke_authenticated_user_requests",
Help: "Counter of authenticated requests broken out by username.",
StabilityLevel: metrics.ALPHA,
},
[]string{"username"},
)
authenticatedAttemptsCounter = metrics.NewCounterVec(
&metrics.CounterOpts{
Name: "tke_authentication_attempts",
Help: "Counter of authenticated attempts.",
},
[]string{"result"},
)
authenticatedIgnoreCounter = metrics.NewCounterVec(
&metrics.CounterOpts{
Name: "tke_authenticated_ignore_requests",
Help: "Counter of ignored authentication requests by path prefix and request method.",
StabilityLevel: metrics.ALPHA,
},
[]string{"path_prefix", "method"},
)
defaultIgnoreAuthPathPrefixes = []string{
"/metrics",
"/debug",
"/openapi",
"/version",
"/swagger",
"/favicon.ico",
"/healthz",
}
)
func init() {
legacyregistry.MustRegister(authenticatedUserCounter)
legacyregistry.MustRegister(authenticatedAttemptsCounter)
}
// WithAuthentication creates an http handler that tries to authenticate the
// given request as a user, and then stores any such user found onto the
// provided context for the request. If authentication fails or returns an error
// the failed handler is used. On success, "Authorization" header is removed
// from the request and handler is invoked to serve the request.
func WithAuthentication(handler http.Handler, auth authenticator.Request, failed http.Handler, apiAuds authenticator.Audiences, ignorePathPrefixes []string) http.Handler {
if auth == nil {
log.Warnf("Authentication is disabled")
return handler
}
allIgnorePathPrefixes := MakeAllIgnoreAuthPathPrefixes(ignorePathPrefixes)
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
if req.Method == http.MethodOptions {
authenticatedIgnoreCounter.WithLabelValues("ALL", http.MethodOptions).Inc()
handler.ServeHTTP(w, req)
return
}
ignorePathPrefix := ""
reqPath := strings.ToLower(req.URL.Path)
for _, pathPrefix := range allIgnorePathPrefixes {
if strings.HasPrefix(reqPath, strings.ToLower(pathPrefix)) {
ignorePathPrefix = pathPrefix
break
}
}
if ignorePathPrefix != "" {
authenticatedIgnoreCounter.WithLabelValues(ignorePathPrefix, "ALL").Inc()
handler.ServeHTTP(w, req)
return
}
if len(apiAuds) > 0 {
req = req.WithContext(authenticator.WithAudiences(req.Context(), apiAuds))
}
resp, ok, err := auth.AuthenticateRequest(req)
if err != nil || !ok {
if err != nil {
log.Errorf("Unable to authenticate the request due to an error: %v", err)
authenticatedAttemptsCounter.WithLabelValues(errorLabel).Inc()
} else if !ok {
authenticatedAttemptsCounter.WithLabelValues(failureLabel).Inc()
}
failed.ServeHTTP(w, req)
return
}
// authorization header is not required anymore in case of a successful authentication.
req.Header.Del("Authorization")
req = req.WithContext(genericapirequest.WithUser(req.Context(), resp.User))
authenticatedUserCounter.WithLabelValues(compressUsername(resp.User.GetName())).Inc()
authenticatedAttemptsCounter.WithLabelValues(successLabel).Inc()
handler.ServeHTTP(w, req)
})
}
func MakeAllIgnoreAuthPathPrefixes(pathPrefixes []string) []string {
if len(pathPrefixes) > 0 {
return append(defaultIgnoreAuthPathPrefixes, pathPrefixes...)
}
return defaultIgnoreAuthPathPrefixes
}
func Unauthorized(s runtime.NegotiatedSerializer, supportsBasicAuth bool) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
if supportsBasicAuth {
w.Header().Set("WWW-Authenticate", `Basic realm="tke"`)
}
ctx := req.Context()
requestInfo, found := genericapirequest.RequestInfoFrom(ctx)
if !found {
responsewriters.InternalError(w, req, errors.New("no RequestInfo found in the context"))
return
}
gv := schema.GroupVersion{Group: requestInfo.APIGroup, Version: requestInfo.APIVersion}
responsewriters.ErrorNegotiated(apierrors.NewUnauthorized("Unauthorized"), s, gv, w, req)
})
}
// compressUsername maps all possible usernames onto a small set of categories
// of usernames. This is done both to limit the cardinality of the
// authorized_user_requests metric, and to avoid pushing actual usernames in the
// metric.
func compressUsername(username string) string {
switch {
// Known internal identities.
case username == "admin" ||
username == "client":
return username
// Probably an email address.
case strings.Contains(username, "@"):
return "email_id"
// Anything else (custom service accounts, custom external identities, etc.)
default:
return "other"
}
}