Make client a top-level package for consistency

5 files changed, 380 insertions, 0 deletions

diff --git a/client/client.go b/client/client.go
new file mode 100644
index 0000000..ba5b900
--- /dev/null
+++ b/client/client.go
@@ -0,0 +1,113 @@
+package client
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"path"
+	"time"
+
+	"github.com/nsheridan/cashier/lib"
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+)
+
+// InstallCert adds the private key and signed certificate to the ssh agent.
+func InstallCert(a agent.Agent, cert *ssh.Certificate, key Key) error {
+	t := time.Unix(int64(cert.ValidBefore), 0)
+	lifetime := t.Sub(time.Now()).Seconds()
+	comment := fmt.Sprintf("%s [Expires %s]", cert.KeyId, t)
+	pubcert := agent.AddedKey{
+		PrivateKey:   key,
+		Certificate:  cert,
+		Comment:      comment,
+		LifetimeSecs: uint32(lifetime),
+	}
+	if err := a.Add(pubcert); err != nil {
+		return fmt.Errorf("error importing certificate: %s", err)
+	}
+	privkey := agent.AddedKey{
+		PrivateKey:   key,
+		Comment:      comment,
+		LifetimeSecs: uint32(lifetime),
+	}
+	if err := a.Add(privkey); err != nil {
+		return fmt.Errorf("error importing key: %s", err)
+	}
+	return nil
+}
+
+// send the signing request to the CA.
+func send(s []byte, token, ca string, ValidateTLSCertificate bool) (*lib.SignResponse, error) {
+	transport := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: !ValidateTLSCertificate},
+	}
+	client := &http.Client{Transport: transport}
+	u, err := url.Parse(ca)
+	if err != nil {
+		return nil, err
+	}
+	u.Path = path.Join(u.Path, "/sign")
+	req, err := http.NewRequest("POST", u.String(), 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))
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("Bad response from server: %s", resp.Status)
+	}
+	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
+}
+
+// Sign sends the public key to the CA to be signed.
+func Sign(pub ssh.PublicKey, token string, conf *Config) (*ssh.Certificate, error) {
+	validity, err := time.ParseDuration(conf.Validity)
+	if err != nil {
+		return nil, err
+	}
+	marshaled := ssh.MarshalAuthorizedKey(pub)
+	// Remove the trailing newline.
+	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, conf.CA, conf.ValidateTLSCertificate)
+	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
+}
diff --git a/client/client_test.go b/client/client_test.go
new file mode 100644
index 0000000..b7df3fd
--- /dev/null
+++ b/client/client_test.go
@@ -0,0 +1,117 @@
+package client
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/nsheridan/cashier/lib"
+	"github.com/nsheridan/cashier/testdata"
+
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
+)
+
+func TestLoadCert(t *testing.T) {
+	t.Parallel()
+	priv, _ := ssh.ParseRawPrivateKey(testdata.Priv)
+	key := priv.(*rsa.PrivateKey)
+	pub, _ := ssh.NewPublicKey(&key.PublicKey)
+	c := &ssh.Certificate{
+		KeyId:       "test_key_12345",
+		Key:         pub,
+		CertType:    ssh.UserCert,
+		ValidBefore: ssh.CertTimeInfinity,
+		ValidAfter:  0,
+	}
+	signer, err := ssh.NewSignerFromKey(key)
+	if err != nil {
+		t.Error(err)
+	}
+	c.SignCert(rand.Reader, signer)
+	a := agent.NewKeyring()
+	if err := InstallCert(a, c, key); err != nil {
+		t.Error(err)
+	}
+	listedKeys, err := a.List()
+	if err != nil {
+		t.Errorf("Error reading from agent: %v", err)
+	}
+	if len(listedKeys) != 2 {
+		t.Errorf("Expected 2 keys, got %d", len(listedKeys))
+	}
+	if !bytes.Equal(listedKeys[0].Marshal(), c.Marshal()) {
+		t.Error("Certs not equal")
+	}
+	for _, k := range listedKeys {
+		exp := time.Unix(int64(c.ValidBefore), 0).String()
+		want := fmt.Sprintf("%s [Expires %s]", c.KeyId, exp)
+		if k.Comment != want {
+			t.Errorf("key comment:\nwanted:%s\ngot: %s", want, k.Comment)
+		}
+	}
+}
+
+func TestSignGood(t *testing.T) {
+	t.Parallel()
+	res := &lib.SignResponse{
+		Status:   "ok",
+		Response: string(testdata.Cert),
+	}
+	j, _ := json.Marshal(res)
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, string(j))
+	}))
+	defer ts.Close()
+	_, err := send([]byte(`{}`), "token", ts.URL, true)
+	if err != nil {
+		t.Error(err)
+	}
+	k, _, _, _, err := ssh.ParseAuthorizedKey(testdata.Pub)
+	if err != nil {
+		t.Error(err)
+	}
+	c := &Config{
+		CA:       ts.URL,
+		Validity: "24h",
+	}
+	cert, err := Sign(k, "token", c)
+	if cert == nil && err != nil {
+		t.Error(err)
+	}
+}
+
+func TestSignBad(t *testing.T) {
+	t.Parallel()
+	res := &lib.SignResponse{
+		Status:   "error",
+		Response: `{"response": "error"}`,
+	}
+	j, _ := json.Marshal(res)
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, string(j))
+	}))
+	defer ts.Close()
+	_, err := send([]byte(`{}`), "token", ts.URL, true)
+	if err != nil {
+		t.Error(err)
+	}
+	k, _, _, _, err := ssh.ParseAuthorizedKey(testdata.Pub)
+	if err != nil {
+		t.Error(err)
+	}
+	c := &Config{
+		CA:       ts.URL,
+		Validity: "24h",
+	}
+	cert, err := Sign(k, "token", c)
+	if cert != nil && err == nil {
+		t.Error(err)
+	}
+}
diff --git a/client/config.go b/client/config.go
new file mode 100644
index 0000000..1cc9401
--- /dev/null
+++ b/client/config.go
@@ -0,0 +1,38 @@
+package client
+
+import (
+	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
+)
+
+// Config holds the client configuration.
+type Config struct {
+	CA                     string `mapstructure:"ca"`
+	Keytype                string `mapstructure:"key_type"`
+	Keysize                int    `mapstructure:"key_size"`
+	Validity               string `mapstructure:"validity"`
+	ValidateTLSCertificate bool   `mapstructure:"validate_tls_certificate"`
+}
+
+func setDefaults() {
+	viper.BindPFlag("ca", pflag.Lookup("ca"))
+	viper.BindPFlag("key_type", pflag.Lookup("key_type"))
+	viper.BindPFlag("key_size", pflag.Lookup("key_size"))
+	viper.BindPFlag("validity", pflag.Lookup("validity"))
+	viper.SetDefault("validateTLSCertificate", true)
+}
+
+// ReadConfig reads the client configuration from a file into a Config struct.
+func ReadConfig(path string) (*Config, error) {
+	setDefaults()
+	viper.SetConfigFile(path)
+	viper.SetConfigType("hcl")
+	if err := viper.ReadInConfig(); err != nil {
+		return nil, err
+	}
+	c := &Config{}
+	if err := viper.Unmarshal(c); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
diff --git a/client/keys.go b/client/keys.go
new file mode 100644
index 0000000..4b3b69e
--- /dev/null
+++ b/client/keys.go
@@ -0,0 +1,84 @@
+package client
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"fmt"
+
+	"golang.org/x/crypto/ed25519"
+	"golang.org/x/crypto/ssh"
+)
+
+// Key is a private key.
+type Key interface{}
+type keyfunc func(int) (Key, ssh.PublicKey, error)
+
+var (
+	keytypes = map[string]keyfunc{
+		"rsa":     generateRSAKey,
+		"ecdsa":   generateECDSAKey,
+		"ed25519": generateED25519Key,
+	}
+)
+
+func generateED25519Key(bits int) (Key, ssh.PublicKey, error) {
+	p, k, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	pub, err := ssh.NewPublicKey(p)
+	if err != nil {
+		return nil, nil, err
+	}
+	return &k, pub, nil
+}
+
+func generateRSAKey(bits int) (Key, 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) (Key, 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
+}
+
+// GenerateKey generates a ssh key-pair according to the type and size specified.
+func GenerateKey(keytype string, bits int) (Key, ssh.PublicKey, error) {
+	f, ok := keytypes[keytype]
+	if !ok {
+		var valid []string
+		for k := range keytypes {
+			valid = append(valid, k)
+		}
+		return nil, nil, fmt.Errorf("Unsupported key type %s. Valid choices are %s", keytype, valid)
+	}
+	return f(bits)
+}
diff --git a/client/keys_test.go b/client/keys_test.go
new file mode 100644
index 0000000..9e930d5
--- /dev/null
+++ b/client/keys_test.go
@@ -0,0 +1,28 @@
+package client
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestGenerateKeys(t *testing.T) {
+	var tests = []struct {
+		key  string
+		size int
+		want string
+	}{
+		{"ecdsa", 256, "*ecdsa.PrivateKey"},
+		{"rsa", 1024, "*rsa.PrivateKey"},
+		{"ed25519", 256, "*ed25519.PrivateKey"},
+	}
+
+	for _, tst := range tests {
+		k, _, err := GenerateKey(tst.key, tst.size)
+		if err != nil {
+			t.Error(err)
+		}
+		if reflect.TypeOf(k).String() != tst.want {
+			t.Errorf("Wrong key type returned. Got %s, wanted %s", reflect.TypeOf(k).String(), tst.want)
+		}
+	}
+}