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/* Authors:
* Christian Heimes <cheimes@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright (C) 2015 Red Hat, Inc.
* All rights reserved.
*
* Custodia entrypoint for Docker
*/
package main
import (
"bufio"
"fmt"
"encoding/json"
"errors"
"log"
"net"
"net/http"
"os"
"path"
"strings"
"syscall"
)
const PREFIX string = "CUSTODIA_"
const SECRET_PREFIX string = PREFIX + "SECRET_"
const BASE_PATH string = "http+unix://localhost/secrets/"
/* Unix Domain Socket transport
*
*/
type UDSTransport struct {
SocketPath string
}
func (uds *UDSTransport) RoundTrip(req *http.Request) (*http.Response, error) {
if req.URL == nil {
if req.Body != nil {
req.Body.Close()
}
return nil, errors.New("uds: nil Request.URL")
}
if req.Header == nil {
if req.Body != nil {
req.Body.Close()
}
return nil, errors.New("uds: nil Request.Header")
}
if req.URL.Scheme != "http+unix" {
if req.Body != nil {
req.Body.Close()
}
return nil, errors.New("uds: unsupported protocol scheme " + req.URL.Scheme)
}
if req.URL.Host != "localhost" {
if req.Body != nil {
req.Body.Close()
}
return nil, errors.New("uds: Host must be 'localhost'")
}
conn, err := net.Dial("unix", uds.SocketPath)
if err != nil {
return nil, err
}
// XXX: leaks conn
req.Write(conn)
return http.ReadResponse(bufio.NewReader(conn), req)
}
func UnixClient(path string) *http.Client {
transport := new(http.Transport)
uds := &UDSTransport{SocketPath: path}
transport.RegisterProtocol("http+unix", uds)
client := &http.Client{Transport: transport}
return client
}
/* Custodia client
*/
type CustodiaMessage struct {
Type string `json:"type"`
Value string `json:"value"`
}
type CustodiaSecret struct {
Name string
Value string
Secret string
Fetched bool
}
type CustodiaClient struct {
SocketPath string
BasePath string
Prefix string
SecretPrefix string
RemoteUser string
Secrets []*CustodiaSecret
}
func NewCustodiaClient(socketpath, remoteuser string) *CustodiaClient {
return &CustodiaClient{
SocketPath: socketpath,
BasePath: BASE_PATH,
Prefix: PREFIX,
SecretPrefix: SECRET_PREFIX,
RemoteUser: remoteuser,
Secrets: []*CustodiaSecret{},
}
}
func (cc *CustodiaClient) FindEnvs() {
for _, env := range os.Environ() {
if strings.HasPrefix(env, cc.SecretPrefix) {
pair := strings.SplitN(env, "=", 2)
sec := &CustodiaSecret{
Name: pair[0][len(cc.SecretPrefix):],
Value: pair[1],
Secret: "",
Fetched: false,
}
cc.Secrets = append(cc.Secrets, sec)
}
}
}
func (cc *CustodiaClient) QueryCustodia() {
if len(cc.Secrets) == 0 {
return
}
client := UnixClient(cc.SocketPath)
for _, sec := range cc.Secrets {
path := cc.BasePath + sec.Value
req, err := http.NewRequest(
"GET", path, nil)
if err != nil {
panic(err)
}
if cc.RemoteUser != "" {
req.Header.Add("REMOTE_USER", cc.RemoteUser)
}
resp, err := client.Do(req)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
log.Fatalf("%v: %v\n", path, resp.Status)
}
var m CustodiaMessage
body := json.NewDecoder(resp.Body)
err = body.Decode(&m)
if err != nil {
log.Fatalf("%v json error: %v", path, err)
}
if len(m.Value) > 0 {
sec.Secret = m.Value
sec.Fetched = true
}
}
}
func (cc CustodiaClient) MakeEnv() []string {
environ := []string{}
for _, env := range os.Environ() {
if ! strings.HasPrefix(env, cc.Prefix) {
environ = append(environ, env)
}
}
for _, sec := range cc.Secrets {
if sec.Fetched {
env := fmt.Sprintf("%s=%s", sec.Name, sec.Secret)
environ = append(environ, env)
}
}
return environ
}
func (cc CustodiaClient) Debug() {
fmt.Printf("%v secret(s):\n", len(cc.Secrets))
for _, sec := range cc.Secrets {
fmt.Printf(" %+v\n", *sec)
}
fmt.Println("Environ:")
environ := cc.MakeEnv()
for _, env := range environ {
fmt.Printf(" %v\n", env)
}
fmt.Println()
}
func main() {
debug := os.Getenv("CUSTODIA_DEBUG") != ""
if len(os.Args) < 2 {
log.Fatalf("%s entrypoint [args]", os.Args[0])
}
socketpath := os.Getenv("CUSTODIA_SOCKET")
if socketpath == "" {
// default socket is in the same directory as program
socketpath = path.Join(path.Dir(os.Args[0]), "server_socket")
}
remoteuser := os.Getenv("CUSTODIA_REMOTE_USER")
client := NewCustodiaClient(socketpath, remoteuser)
if debug {
fmt.Printf("%+v\n", client)
}
client.FindEnvs()
client.QueryCustodia()
environ := client.MakeEnv()
if debug {
client.Debug()
}
args := os.Args[1:]
syscall.Exec(args[0], args, environ)
}
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