Create initial version of simple wrapper

.gitignore

@@ -10,3 +10,4 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+.vscode

cmd/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"syscall"
+
+	"github.com/connectedcars/auth-wrapper/ssh"
+)
+
+func main() {
+	sshKeyPath := os.Getenv("SSH_KEY_PATH")
+	sshKeyPassword := os.Getenv("SSH_KEY_PASSWORD")
+	os.Unsetenv("SSH_KEY_PATH")
+	os.Unsetenv("SSH_KEY_PASSWORD")
+
+	if sshKeyPath != "" {
+		privateKeyBytes, err := ioutil.ReadFile(sshKeyPath)
+		if err != nil {
+			fmt.Printf("Failed to read SSHPrivateKey from %s: %v\n", sshKeyPath, err)
+			os.Exit(1)
+		}
+		sshAuthSock, err := ssh.SetupAgent(privateKeyBytes, sshKeyPassword)
+		if err != nil {
+			fmt.Printf("Failed to start ssh agent server: %v\n", err)
+			os.Exit(1)
+		}
+		os.Setenv("SSH_AUTH_SOCK", sshAuthSock)
+	}
+
+	if len(os.Args) < 2 {
+		fmt.Println("auth-wrapper cmd args")
+		os.Exit(1)
+	}
+
+	// Setup exec command
+	command := os.Args[1]
+	args := os.Args[2:]
+	cmd := exec.Command(command, args...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Start(); err != nil {
+		fmt.Printf("cmd.Start: %v\n", err)
+		os.Exit(1)
+	}
+
+	if err := cmd.Wait(); err != nil {
+		if exiterr, ok := err.(*exec.ExitError); ok {
+			if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
+				os.Exit(status.ExitStatus())
+			}
+		} else {
+			fmt.Printf("cmd.Wait: %v\n", err)
+			os.Exit(1)
+		}
+	}
+}

go.mod

@@ -0,0 +1,5 @@
+module github.com/connectedcars/auth-wrapper
+
+go 1.13
+
+require golang.org/x/crypto v0.0.0-20191108234033-bd318be0434a

go.sum

@@ -0,0 +1,7 @@
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191108234033-bd318be0434a h1:R/qVym5WAxsZWQqZCwDY/8sdVKV1m1WgU4/S5IRQAzc=
+golang.org/x/crypto v0.0.0-20191108234033-bd318be0434a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

ssh/sshagent.go

@@ -0,0 +1,87 @@
+package ssh
+
+import (
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"net"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+)
+
+// SetupAgent start an SSH Agent server and loads the given private key
+func SetupAgent(privateKeyBytes []byte, passphrase string) (sshAuthSock string, error error) {
+	sshAgent := agent.NewKeyring()
+
+	privateKey, err := parsePrivateSSHKey(privateKeyBytes, passphrase)
+	if err != nil {
+		return "", err
+	}
+
+	err = sshAgent.Add(agent.AddedKey{PrivateKey: privateKey, Comment: "my private key"})
+	if err != nil {
+		return "", err
+	}
+
+	// Generate random filename
+	dir, err := ioutil.TempDir(os.TempDir(), "")
+	if err != nil {
+		log.Fatal(err)
+	}
+	sshAuthSock = dir + "/" + generateRandomString(8) + ".sock"
+
+	go func() {
+		// Open SSH agent socket
+		if err := os.RemoveAll(sshAuthSock); err != nil {
+			log.Fatal(err)
+		}
+		l, err := net.Listen("unix", sshAuthSock)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer l.Close()
+
+		// Accept new connections, dispatching them to an ssh agent server in the background
+		for {
+			conn, err := l.Accept()
+			if err != nil {
+				log.Fatal("accept error:", err)
+			}
+
+			go agent.ServeAgent(sshAgent, conn)
+		}
+	}()
+
+	return sshAuthSock, err
+}
+
+const letterBytes = "abcdefghijklmnopqrstuvwxyz"
+
+func generateRandomString(n int) string {
+	b := make([]byte, n)
+	for i := range b {
+		b[i] = letterBytes[rand.Intn(len(letterBytes))]
+	}
+	return string(b)
+}
+
+func parsePrivateSSHKey(privateKeyBytes []byte, passphrase string) (interface{}, error) {
+	var err error
+	var privateKey interface{}
+	if strings.Contains(string(privateKeyBytes), "ENCRYPTED") {
+		privateKey, err = ssh.ParseRawPrivateKeyWithPassphrase(privateKeyBytes, []byte(passphrase))
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		privateKey, err = ssh.ParseRawPrivateKey(privateKeyBytes)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return privateKey, nil
+}

ssh/sshagent_test.go

@@ -0,0 +1,57 @@
+package ssh
+
+import (
+	"testing"
+)
+
+var privateKeyBytes = []byte(`-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+`)
+
+func TestSshAgent(t *testing.T) {
+	//privateKeyBytes, err := ioutil.ReadFile("/home/user/.ssh/id_rsa")
+	//if err != nil {
+	//	t.Fatal(err)
+	//}
+
+	/* sshAuthSock, err := setupAgent(privateKeyBytes, "Qwerty1234")
+	if err != nil {
+		t.Error(err)
+	}
+
+	// Setup exec command
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, "ssh", []string{"-v", "git@github.com"}...)
+	//cmd := exec.CommandContext(ctx, "ssh-add", []string{"-l"}...)
+	cmd.Env = []string{"SSH_AUTH_SOCK=" + sshAuthSock}
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err = cmd.Start()
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = cmd.Wait()
+	if ctx.Err() == context.DeadlineExceeded {
+		t.Error("timed out")
+	}
+	if err != nil {
+		t.Error(err)
+	} */
+
+}