A simple Go program demonstrating two applications of code.google.com/p/go.crypto/ssh: Authentication using public key crypto and the tunneling of a HTTP request through the resulting SSH connection. In this gist, the remote SSH server is on localhost and the HTTP URL tunneled over the established secure connection is http://localhost:6060. But,…

ssh-pk-auth-http-tunnel.go

package main
 
import (
	"code.google.com/p/go.crypto/ssh"
	"crypto"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	//"fmt"
	"io"
	"io/ioutil"
	"os"
	"log"
	"net/http"
	"os/user"
	"path"
)
 
type keychain struct {
	key *rsa.PrivateKey
}
 
func (k *keychain) Key(i int) (interface{}, error) {
	if i != 0 {
		return nil, nil
	}
	return &k.key.PublicKey, nil
}
 
func (k *keychain) Sign(i int, rand io.Reader, data []byte) (sig []byte, err error) {
	hashFunc := crypto.SHA1
	h := hashFunc.New()
	h.Write(data)
	digest := h.Sum(nil)
	return rsa.SignPKCS1v15(rand, k.key, hashFunc, digest)
}
 
func main() {
	u, err := user.Current()
	if err != nil {
		panic(err)
	}

	idRSAFileName := path.Join(u.HomeDir, ".ssh", "id_rsa")
	
	idRSAFile, err := os.Open(idRSAFileName)
	if err != nil {
		panic(err)
	}
	defer idRSAFile.Close()

	privateKey, err := ioutil.ReadAll(idRSAFile)
	if err != nil {
		panic(err)
	}

	block, _ := pem.Decode(privateKey)
	if block == nil {
		log.Fatalln("No PEM encoded block found in", idRSAFile.Name())
	}

	rsakey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
	if err != nil {
		log.Fatalln(err)
	}

	clientKey := &keychain{rsakey}
	clientConfig := &ssh.ClientConfig{
		User:  u.Username,
		Auth: []ssh.ClientAuth{
			ssh.ClientAuthKeyring(clientKey),
		},
	}

	client, err := ssh.Dial("tcp", "localhost:22", clientConfig)
	if err != nil {
		log.Fatalln("Failed to dial: " + err.Error())
	}
	
	tr := &http.Transport {
		Dial: client.Dial,
	}

	httpClient := &http.Client {
		Transport: tr,
	}

	resp, err := httpClient.Get("http://localhost:6060")
	if err != nil {
		log.Fatalln(err)
	}
	defer resp.Body.Close()

	_, err = io.Copy(os.Stdout, resp.Body)
	
}