k8s.io/apiserver@v0.31.1/pkg/server/options/serving_with_loopback.go (about)

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package options
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"github.com/google/uuid"
    23  
    24  	"k8s.io/apiserver/pkg/server"
    25  	"k8s.io/apiserver/pkg/server/dynamiccertificates"
    26  	"k8s.io/client-go/rest"
    27  	certutil "k8s.io/client-go/util/cert"
    28  )
    29  
    30  type SecureServingOptionsWithLoopback struct {
    31  	*SecureServingOptions
    32  }
    33  
    34  func (o *SecureServingOptions) WithLoopback() *SecureServingOptionsWithLoopback {
    35  	return &SecureServingOptionsWithLoopback{o}
    36  }
    37  
    38  // ApplyTo fills up serving information in the server configuration.
    39  func (s *SecureServingOptionsWithLoopback) ApplyTo(secureServingInfo **server.SecureServingInfo, loopbackClientConfig **rest.Config) error {
    40  	if s == nil || s.SecureServingOptions == nil || secureServingInfo == nil {
    41  		return nil
    42  	}
    43  
    44  	if err := s.SecureServingOptions.ApplyTo(secureServingInfo); err != nil {
    45  		return err
    46  	}
    47  
    48  	if *secureServingInfo == nil || loopbackClientConfig == nil {
    49  		return nil
    50  	}
    51  
    52  	// create self-signed cert+key with the fake server.LoopbackClientServerNameOverride and
    53  	// let the server return it when the loopback client connects.
    54  	certPem, keyPem, err := certutil.GenerateSelfSignedCertKey(server.LoopbackClientServerNameOverride, nil, nil)
    55  	if err != nil {
    56  		return fmt.Errorf("failed to generate self-signed certificate for loopback connection: %v", err)
    57  	}
    58  	certProvider, err := dynamiccertificates.NewStaticSNICertKeyContent("self-signed loopback", certPem, keyPem, server.LoopbackClientServerNameOverride)
    59  	if err != nil {
    60  		return fmt.Errorf("failed to generate self-signed certificate for loopback connection: %v", err)
    61  	}
    62  
    63  	// Write to the front of SNICerts so that this overrides any other certs with the same name
    64  	(*secureServingInfo).SNICerts = append([]dynamiccertificates.SNICertKeyContentProvider{certProvider}, (*secureServingInfo).SNICerts...)
    65  
    66  	secureLoopbackClientConfig, err := (*secureServingInfo).NewLoopbackClientConfig(uuid.New().String(), certPem)
    67  	switch {
    68  	// if we failed and there's no fallback loopback client config, we need to fail
    69  	case err != nil && *loopbackClientConfig == nil:
    70  		(*secureServingInfo).SNICerts = (*secureServingInfo).SNICerts[1:]
    71  		return err
    72  
    73  	// if we failed, but we already have a fallback loopback client config (usually insecure), allow it
    74  	case err != nil && *loopbackClientConfig != nil:
    75  
    76  	default:
    77  		*loopbackClientConfig = secureLoopbackClientConfig
    78  	}
    79  
    80  	return nil
    81  }