node_exporter/https/tls_config.go

124 lines
3.5 KiB
Go

// Copyright 2019 The Prometheus Authors
// 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
//
// http://www.apache.org/licenses/LICENSE-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 OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package https allows the implementation of TLS.
package https
import (
"crypto/tls"
"crypto/x509"
"io/ioutil"
"net/http"
"github.com/pkg/errors"
"gopkg.in/yaml.v2"
)
type Config struct {
TLSConfig TLSStruct `yaml:"tlsConfig"`
}
type TLSStruct struct {
TLSCertPath string `yaml:"tlsCertPath"`
TLSKeyPath string `yaml:"tlsKeyPath"`
ClientAuth string `yaml:"clientAuth"`
ClientCAs string `yaml:"clientCAs"`
}
func getTLSConfig(configPath string) (*tls.Config, error) {
content, err := ioutil.ReadFile(configPath)
if err != nil {
return nil, err
}
c := &Config{}
err = yaml.Unmarshal(content, c)
if err != nil {
return nil, err
}
return configToTLSConfig(&c.TLSConfig)
}
func configToTLSConfig(c *TLSStruct) (*tls.Config, error) {
cfg := &tls.Config{}
if len(c.TLSCertPath) == 0 {
return nil, errors.New("missing TLSCertPath")
}
if len(c.TLSKeyPath) == 0 {
return nil, errors.New("missing TLSKeyPath")
}
loadCert := func() (*tls.Certificate, error) {
cert, err := tls.LoadX509KeyPair(c.TLSCertPath, c.TLSKeyPath)
if err != nil {
return nil, errors.Wrap(err, "failed to load X509KeyPair")
}
return &cert, nil
}
// Confirm that certificate and key paths are valid.
if _, err := loadCert(); err != nil {
return nil, err
}
cfg.GetCertificate = func(*tls.ClientHelloInfo) (*tls.Certificate, error) {
return loadCert()
}
if len(c.ClientCAs) > 0 {
clientCAPool := x509.NewCertPool()
clientCAFile, err := ioutil.ReadFile(c.ClientCAs)
if err != nil {
return nil, err
}
clientCAPool.AppendCertsFromPEM(clientCAFile)
cfg.ClientCAs = clientCAPool
}
if len(c.ClientAuth) > 0 {
switch s := (c.ClientAuth); s {
case "NoClientCert":
cfg.ClientAuth = tls.NoClientCert
case "RequestClientCert":
cfg.ClientAuth = tls.RequestClientCert
case "RequireClientCert":
cfg.ClientAuth = tls.RequireAnyClientCert
case "VerifyClientCertIfGiven":
cfg.ClientAuth = tls.VerifyClientCertIfGiven
case "RequireAndVerifyClientCert":
cfg.ClientAuth = tls.RequireAndVerifyClientCert
case "":
cfg.ClientAuth = tls.NoClientCert
default:
return nil, errors.New("Invalid ClientAuth: " + s)
}
}
if len(c.ClientCAs) > 0 && cfg.ClientAuth == tls.NoClientCert {
return nil, errors.New("Client CA's have been configured without a Client Auth Policy")
}
return cfg, nil
}
// Listen starts the server on the given address. If tlsConfigPath isn't empty the server connection will be started using TLS.
func Listen(server *http.Server, tlsConfigPath string) error {
if (tlsConfigPath) == "" {
return server.ListenAndServe()
}
var err error
server.TLSConfig, err = getTLSConfig(tlsConfigPath)
if err != nil {
return err
}
// Set the GetConfigForClient method of the HTTPS server so that the config
// and certs are reloaded on new connections.
server.TLSConfig.GetConfigForClient = func(*tls.ClientHelloInfo) (*tls.Config, error) {
return getTLSConfig(tlsConfigPath)
}
return server.ListenAndServeTLS("", "")
}