Initial commit

2 files changed, 185 insertions, 0 deletions

diff --git a/client/keys.go b/client/keys.go
new file mode 100644
index 0000000..4acfbb9
--- /dev/null
+++ b/client/keys.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+
+	"golang.org/x/crypto/ssh"
+)
+
+const (
+	rsaKey   = "rsa"
+	ecdsaKey = "ecdsa"
+)
+
+type key interface{}
+
+func generateRSAKey(bits int) (*rsa.PrivateKey, ssh.PublicKey, error) {
+	k, err := rsa.GenerateKey(rand.Reader, bits)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(&k.PublicKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	return k, pub, nil
+}
+
+func generateECDSAKey(bits int) (*ecdsa.PrivateKey, ssh.PublicKey, error) {
+	var curve elliptic.Curve
+	switch bits {
+	case 256:
+		curve = elliptic.P256()
+	case 384:
+		curve = elliptic.P384()
+	case 521:
+		curve = elliptic.P521()
+	default:
+		return nil, nil, fmt.Errorf("Unsupported key size. Valid sizes are '256', '384', '521'")
+	}
+	k, err := ecdsa.GenerateKey(curve, rand.Reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(&k.PublicKey)
+	if err != nil {
+		return nil, nil, err
+	}
+	return k, pub, nil
+}
+
+func generateKey(keytype string, bits int) (key, ssh.PublicKey, error) {
+	switch keytype {
+	case rsaKey:
+		return generateRSAKey(bits)
+	case ecdsaKey:
+		return generateECDSAKey(bits)
+	default:
+		return nil, nil, fmt.Errorf("Unsupported key type %s. Valid choices are [%s, %s]", keytype, rsaKey, ecdsaKey)
+	}
+}
diff --git a/client/main.go b/client/main.go
new file mode 100644
index 0000000..10a3646
--- /dev/null
+++ b/client/main.go
@@ -0,0 +1,121 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/nsheridan/cashier/lib"
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+)
+
+var (
+	url      = flag.String("url", "http://localhost:10000/sign", "Signing URL")
+	keybits  = flag.Int("bits", 4096, "Key size")
+	validity = flag.Duration("validity", time.Hour*24, "Key validity")
+	keytype  = flag.String("key_type", "rsa", "Type of private key to generate - rsa or ecdsa")
+)
+
+func installCert(a agent.Agent, cert *ssh.Certificate, key key) error {
+	pubcert := agent.AddedKey{
+		PrivateKey:  key,
+		Certificate: cert,
+		Comment:     cert.KeyId,
+	}
+	if err := a.Add(pubcert); err != nil {
+		return fmt.Errorf("error importing certificate: %s", err)
+	}
+	return nil
+}
+
+func send(s []byte, token string) (*lib.SignResponse, error) {
+	req, err := http.NewRequest("POST", *url, bytes.NewReader(s))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Add("Accept", "application/json")
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("Bad response from server: %s", resp.Status)
+	}
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	c := &lib.SignResponse{}
+	if err := json.Unmarshal(body, c); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func sign(pub ssh.PublicKey, token string) (*ssh.Certificate, error) {
+	marshaled := ssh.MarshalAuthorizedKey(pub)
+	marshaled = marshaled[:len(marshaled)-1]
+	s, err := json.Marshal(&lib.SignRequest{
+		Key:        string(marshaled),
+		ValidUntil: time.Now().Add(*validity),
+	})
+	if err != nil {
+		return nil, err
+	}
+	resp, err := send(s, token)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Status != "ok" {
+		return nil, fmt.Errorf("error: %s", resp.Response)
+	}
+	k, _, _, _, err := ssh.ParseAuthorizedKey([]byte(resp.Response))
+	if err != nil {
+		return nil, err
+	}
+	cert, ok := k.(*ssh.Certificate)
+	if !ok {
+		return nil, fmt.Errorf("did not receive a certificate from server")
+	}
+	return cert, nil
+}
+
+func main() {
+	flag.Parse()
+
+	priv, pub, err := generateKey(*keytype, *keybits)
+	if err != nil {
+		log.Fatalln("Error generating key pair: ", err)
+	}
+
+	fmt.Print("Enter token: ")
+	var token string
+	fmt.Scanln(&token)
+
+	cert, err := sign(pub, token)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	sock, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
+	if err != nil {
+		log.Fatalln("Error connecting to agent: %s", err)
+	}
+	defer sock.Close()
+	a := agent.NewClient(sock)
+	if err := installCert(a, cert, priv); err != nil {
+		log.Fatalln(err)
+	}
+	fmt.Println("Certificate added.")
+}