/
ssh_agent.go
201 lines (164 loc) · 4.83 KB
/
ssh_agent.go
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package ssh_agent
import (
"context"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"path/filepath"
uuid "github.com/satori/go.uuid"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/agent"
"github.com/werf/logboek"
"github.com/werf/werf/pkg/util"
"github.com/werf/werf/pkg/werf"
)
var (
SSHAuthSock string
tmpSockPath string
)
func setupProcessSSHAgent(sshAuthSock string) error {
SSHAuthSock = sshAuthSock
return os.Setenv("SSH_AUTH_SOCK", SSHAuthSock)
}
func Init(ctx context.Context, keys []string) error {
for _, key := range keys {
if keyExists, err := util.FileExists(key); !keyExists {
return fmt.Errorf("specified ssh key %s does not exist", key)
} else if err != nil {
return fmt.Errorf("specified ssh key %s does not exist: %v", key, err)
}
}
if len(keys) > 0 {
agentSock, err := runSSHAgentWithKeys(ctx, keys)
if err != nil {
return fmt.Errorf("unable to run ssh agent with specified keys: %s", err)
}
if err := setupProcessSSHAgent(agentSock); err != nil {
return fmt.Errorf("unable to init ssh auth socket to %q: %s", agentSock, err)
}
return nil
}
systemAgentSock := os.Getenv("SSH_AUTH_SOCK")
systemAgentSockExists, _ := util.FileExists(systemAgentSock)
if systemAgentSock != "" && systemAgentSockExists {
SSHAuthSock = systemAgentSock
logboek.Context(ctx).Info().LogF("Using system ssh-agent: %s\n", systemAgentSock)
return nil
}
var defaultKeys []string
for _, defaultFileName := range []string{"id_rsa", "id_dsa"} {
path := filepath.Join(os.Getenv("HOME"), ".ssh", defaultFileName)
if keyExists, _ := util.FileExists(path); keyExists {
defaultKeys = append(defaultKeys, path)
}
}
if len(defaultKeys) > 0 {
var validKeys []string
for _, key := range defaultKeys {
keyData, err := ioutil.ReadFile(key)
if err != nil {
logboek.Context(ctx).Warn().LogF("WARNING: cannot read default key %s: %s\n", key, err)
continue
}
_, err = ssh.ParseRawPrivateKey(keyData)
if err != nil {
logboek.Context(ctx).Warn().LogF("WARNING: default key %s validation error: %s\n", key, err)
continue
}
validKeys = append(validKeys, key)
}
if len(validKeys) > 0 {
agentSock, err := runSSHAgentWithKeys(ctx, validKeys)
if err != nil {
return fmt.Errorf("unable to run ssh agent with specified keys: %s", err)
}
if err := setupProcessSSHAgent(agentSock); err != nil {
return fmt.Errorf("unable to init ssh auth socket to %q: %s", agentSock, err)
}
}
}
return nil
}
func Terminate() error {
if tmpSockPath != "" {
err := os.RemoveAll(tmpSockPath)
if err != nil {
return fmt.Errorf("unable to remove tmp ssh agent sock %s: %s", tmpSockPath, err)
}
}
return nil
}
func runSSHAgentWithKeys(ctx context.Context, keys []string) (string, error) {
agentSock, err := runSSHAgent(ctx)
if err != nil {
return "", fmt.Errorf("error running ssh agent: %s", err)
}
for _, key := range keys {
err := addSSHKey(ctx, agentSock, key)
if err != nil {
return "", fmt.Errorf("error adding ssh key %s: %s", key, err)
}
}
return agentSock, nil
}
func runSSHAgent(ctx context.Context) (string, error) {
sockPath := filepath.Join(werf.GetTmpDir(), "werf-ssh-agent", uuid.NewV4().String())
tmpSockPath = sockPath
err := os.MkdirAll(filepath.Dir(sockPath), os.ModePerm)
if err != nil {
return "", err
}
ln, err := net.Listen("unix", sockPath)
if err != nil {
return "", fmt.Errorf("error listen unix sock %s: %s", sockPath, err)
}
logboek.Context(ctx).Info().LogF("Running ssh agent on unix sock: %s\n", sockPath)
go func() {
agnt := agent.NewKeyring()
for {
conn, err := ln.Accept()
if err != nil {
logboek.Context(ctx).Warn().LogF("WARNING: failed to accept ssh-agent connection: %s\n", err)
continue
}
go func() {
var err error
err = agent.ServeAgent(agnt, conn)
if err != nil && err != io.EOF {
logboek.Context(ctx).Warn().LogF("WARNING: ssh-agent server error: %s\n", err)
return
}
err = conn.Close()
if err != nil {
logboek.Context(ctx).Warn().LogF("WARNING: ssh-agent server connection close error: %s\n", err)
return
}
}()
}
}()
return sockPath, nil
}
func addSSHKey(ctx context.Context, authSock string, key string) error {
conn, err := net.Dial("unix", authSock)
if err != nil {
return fmt.Errorf("error dialing with ssh agent %s: %s", authSock, err)
}
defer conn.Close()
agentClient := agent.NewClient(conn)
keyData, err := ioutil.ReadFile(key)
if err != nil {
return fmt.Errorf("error reading key file %s: %s", key, err)
}
privateKey, err := ssh.ParseRawPrivateKey(keyData)
if err != nil {
return fmt.Errorf("error parsing private key %s: %s", key, err)
}
err = agentClient.Add(agent.AddedKey{PrivateKey: privateKey})
if err != nil {
return err
}
logboek.Context(ctx).Info().LogF("Added private key %s to ssh agent %s\n", key, authSock)
return nil
}