github.com/timstclair/heapster@v0.20.0-alpha1/metrics/auth.go (about)

     1  // Copyright 2014 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package main
    16  
    17  import (
    18  	"crypto/x509"
    19  	"fmt"
    20  	"io/ioutil"
    21  	"net/http"
    22  	"strings"
    23  
    24  	"k8s.io/kubernetes/pkg/auth/authenticator"
    25  	"k8s.io/kubernetes/pkg/auth/user"
    26  	x509request "k8s.io/kubernetes/plugin/pkg/auth/authenticator/request/x509"
    27  )
    28  
    29  func newAuthHandler(handler http.Handler) (http.Handler, error) {
    30  	// Authn/Authz setup
    31  	authn, err := newAuthenticatorFromClientCAFile(*argTLSClientCAFile)
    32  	if err != nil {
    33  		return nil, err
    34  	}
    35  
    36  	authz, err := newAuthorizerFromUserList(strings.Split(*argAllowedUsers, ",")...)
    37  	if err != nil {
    38  		return nil, err
    39  	}
    40  
    41  	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
    42  		// Check authn
    43  		user, ok, err := authn.AuthenticateRequest(req)
    44  		if err != nil {
    45  			http.Error(w, err.Error(), http.StatusInternalServerError)
    46  			return
    47  		}
    48  		if !ok {
    49  			http.Error(w, "Unauthorized", http.StatusUnauthorized)
    50  			return
    51  		}
    52  
    53  		// Check authz
    54  		allowed, err := authz.AuthorizeRequest(req, user)
    55  		if err != nil {
    56  			http.Error(w, err.Error(), http.StatusInternalServerError)
    57  			return
    58  		}
    59  		if !allowed {
    60  			http.Error(w, "Forbidden", http.StatusForbidden)
    61  			return
    62  		}
    63  
    64  		handler.ServeHTTP(w, req)
    65  	}), nil
    66  }
    67  
    68  // newAuthenticatorFromClientCAFile returns an authenticator.Request or an error
    69  func newAuthenticatorFromClientCAFile(clientCAFile string) (authenticator.Request, error) {
    70  	opts := x509request.DefaultVerifyOptions()
    71  
    72  	// If at custom CA bundle is provided, load it (otherwise just use system roots)
    73  	if len(clientCAFile) > 0 {
    74  		if caData, err := ioutil.ReadFile(clientCAFile); err != nil {
    75  			return nil, err
    76  		} else if len(caData) > 0 {
    77  			roots := x509.NewCertPool()
    78  			if !roots.AppendCertsFromPEM(caData) {
    79  				return nil, fmt.Errorf("no valid certs found in %s", clientCAFile)
    80  			}
    81  			opts.Roots = roots
    82  		}
    83  	}
    84  
    85  	return x509request.New(opts, x509request.CommonNameUserConversion), nil
    86  }
    87  
    88  type Authorizer interface {
    89  	AuthorizeRequest(req *http.Request, user user.Info) (bool, error)
    90  }
    91  
    92  func newAuthorizerFromUserList(allowedUsers ...string) (Authorizer, error) {
    93  	if len(allowedUsers) == 1 && len(allowedUsers[0]) == 0 {
    94  		return &allowAnyAuthorizer{}, nil
    95  	}
    96  	u := map[string]bool{}
    97  	for _, allowedUser := range allowedUsers {
    98  		u[allowedUser] = true
    99  	}
   100  	return &userAuthorizer{u}, nil
   101  }
   102  
   103  type allowAnyAuthorizer struct{}
   104  
   105  func (a *allowAnyAuthorizer) AuthorizeRequest(req *http.Request, user user.Info) (bool, error) {
   106  	return true, nil
   107  }
   108  
   109  type userAuthorizer struct {
   110  	allowedUsers map[string]bool
   111  }
   112  
   113  func (a *userAuthorizer) AuthorizeRequest(req *http.Request, user user.Info) (bool, error) {
   114  	return a.allowedUsers[user.GetName()], nil
   115  }