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package libtrust
import (
"bytes"
"crypto"
"crypto/elliptic"
"crypto/tls"
"crypto/x509"
"encoding/base32"
"encoding/base64"
"encoding/binary"
"encoding/pem"
"errors"
"fmt"
"math/big"
"net/url"
"os"
"path/filepath"
"strings"
"time"
)
// LoadOrCreateTrustKey will load a PrivateKey from the specified path
func LoadOrCreateTrustKey(trustKeyPath string) (PrivateKey, error) {
if err := os.MkdirAll(filepath.Dir(trustKeyPath), 0700); err != nil {
return nil, err
}
trustKey, err := LoadKeyFile(trustKeyPath)
if err == ErrKeyFileDoesNotExist {
trustKey, err = GenerateECP256PrivateKey()
if err != nil {
return nil, fmt.Errorf("error generating key: %s", err)
}
if err := SaveKey(trustKeyPath, trustKey); err != nil {
return nil, fmt.Errorf("error saving key file: %s", err)
}
dir, file := filepath.Split(trustKeyPath)
if err := SavePublicKey(filepath.Join(dir, "public-"+file), trustKey.PublicKey()); err != nil {
return nil, fmt.Errorf("error saving public key file: %s", err)
}
} else if err != nil {
return nil, fmt.Errorf("error loading key file: %s", err)
}
return trustKey, nil
}
// NewIdentityAuthTLSClientConfig returns a tls.Config configured to use identity
// based authentication from the specified dockerUrl, the rootConfigPath and
// the server name to which it is connecting.
// If trustUnknownHosts is true it will automatically add the host to the
// known-hosts.json in rootConfigPath.
func NewIdentityAuthTLSClientConfig(dockerUrl string, trustUnknownHosts bool, rootConfigPath string, serverName string) (*tls.Config, error) {
tlsConfig := newTLSConfig()
trustKeyPath := filepath.Join(rootConfigPath, "key.json")
knownHostsPath := filepath.Join(rootConfigPath, "known-hosts.json")
u, err := url.Parse(dockerUrl)
if err != nil {
return nil, fmt.Errorf("unable to parse machine url")
}
if u.Scheme == "unix" {
return nil, nil
}
addr := u.Host
proto := "tcp"
trustKey, err := LoadOrCreateTrustKey(trustKeyPath)
if err != nil {
return nil, fmt.Errorf("unable to load trust key: %s", err)
}
knownHosts, err := LoadKeySetFile(knownHostsPath)
if err != nil {
return nil, fmt.Errorf("could not load trusted hosts file: %s", err)
}
allowedHosts, err := FilterByHosts(knownHosts, addr, false)
if err != nil {
return nil, fmt.Errorf("error filtering hosts: %s", err)
}
certPool, err := GenerateCACertPool(trustKey, allowedHosts)
if err != nil {
return nil, fmt.Errorf("Could not create CA pool: %s", err)
}
tlsConfig.ServerName = serverName
tlsConfig.RootCAs = certPool
x509Cert, err := GenerateSelfSignedClientCert(trustKey)
if err != nil {
return nil, fmt.Errorf("certificate generation error: %s", err)
}
tlsConfig.Certificates = []tls.Certificate{{
Certificate: [][]byte{x509Cert.Raw},
PrivateKey: trustKey.CryptoPrivateKey(),
Leaf: x509Cert,
}}
tlsConfig.InsecureSkipVerify = true
testConn, err := tls.Dial(proto, addr, tlsConfig)
if err != nil {
return nil, fmt.Errorf("tls Handshake error: %s", err)
}
opts := x509.VerifyOptions{
Roots: tlsConfig.RootCAs,
CurrentTime: time.Now(),
DNSName: tlsConfig.ServerName,
Intermediates: x509.NewCertPool(),
}
certs := testConn.ConnectionState().PeerCertificates
for i, cert := range certs {
if i == 0 {
continue
}
opts.Intermediates.AddCert(cert)
}
if _, err := certs[0].Verify(opts); err != nil {
if _, ok := err.(x509.UnknownAuthorityError); ok {
if trustUnknownHosts {
pubKey, err := FromCryptoPublicKey(certs[0].PublicKey)
if err != nil {
return nil, fmt.Errorf("error extracting public key from cert: %s", err)
}
pubKey.AddExtendedField("hosts", []string{addr})
if err := AddKeySetFile(knownHostsPath, pubKey); err != nil {
return nil, fmt.Errorf("error adding machine to known hosts: %s", err)
}
} else {
return nil, fmt.Errorf("unable to connect. unknown host: %s", addr)
}
}
}
testConn.Close()
tlsConfig.InsecureSkipVerify = false
return tlsConfig, nil
}
// joseBase64UrlEncode encodes the given data using the standard base64 url
// encoding format but with all trailing '=' characters omitted in accordance
// with the jose specification.
// http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-31#section-2
func joseBase64UrlEncode(b []byte) string {
return strings.TrimRight(base64.URLEncoding.EncodeToString(b), "=")
}
// joseBase64UrlDecode decodes the given string using the standard base64 url
// decoder but first adds the appropriate number of trailing '=' characters in
// accordance with the jose specification.
// http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-31#section-2
func joseBase64UrlDecode(s string) ([]byte, error) {
s = strings.Replace(s, "\n", "", -1)
s = strings.Replace(s, " ", "", -1)
switch len(s) % 4 {
case 0:
case 2:
s += "=="
case 3:
s += "="
default:
return nil, errors.New("illegal base64url string")
}
return base64.URLEncoding.DecodeString(s)
}
func keyIDEncode(b []byte) string {
s := strings.TrimRight(base32.StdEncoding.EncodeToString(b), "=")
var buf bytes.Buffer
var i int
for i = 0; i < len(s)/4-1; i++ {
start := i * 4
end := start + 4
buf.WriteString(s[start:end] + ":")
}
buf.WriteString(s[i*4:])
return buf.String()
}
func keyIDFromCryptoKey(pubKey PublicKey) string {
// Generate and return a 'libtrust' fingerprint of the public key.
// For an RSA key this should be:
// SHA256(DER encoded ASN1)
// Then truncated to 240 bits and encoded into 12 base32 groups like so:
// ABCD:EFGH:IJKL:MNOP:QRST:UVWX:YZ23:4567:ABCD:EFGH:IJKL:MNOP
derBytes, err := x509.MarshalPKIXPublicKey(pubKey.CryptoPublicKey())
if err != nil {
return ""
}
hasher := crypto.SHA256.New()
hasher.Write(derBytes)
return keyIDEncode(hasher.Sum(nil)[:30])
}
func stringFromMap(m map[string]interface{}, key string) (string, error) {
val, ok := m[key]
if !ok {
return "", fmt.Errorf("%q value not specified", key)
}
str, ok := val.(string)
if !ok {
return "", fmt.Errorf("%q value must be a string", key)
}
delete(m, key)
return str, nil
}
func parseECCoordinate(cB64Url string, curve elliptic.Curve) (*big.Int, error) {
curveByteLen := (curve.Params().BitSize + 7) >> 3
cBytes, err := joseBase64UrlDecode(cB64Url)
if err != nil {
return nil, fmt.Errorf("invalid base64 URL encoding: %s", err)
}
cByteLength := len(cBytes)
if cByteLength != curveByteLen {
return nil, fmt.Errorf("invalid number of octets: got %d, should be %d", cByteLength, curveByteLen)
}
return new(big.Int).SetBytes(cBytes), nil
}
func parseECPrivateParam(dB64Url string, curve elliptic.Curve) (*big.Int, error) {
dBytes, err := joseBase64UrlDecode(dB64Url)
if err != nil {
return nil, fmt.Errorf("invalid base64 URL encoding: %s", err)
}
// The length of this octet string MUST be ceiling(log-base-2(n)/8)
// octets (where n is the order of the curve). This is because the private
// key d must be in the interval [1, n-1] so the bitlength of d should be
// no larger than the bitlength of n-1. The easiest way to find the octet
// length is to take bitlength(n-1), add 7 to force a carry, and shift this
// bit sequence right by 3, which is essentially dividing by 8 and adding
// 1 if there is any remainder. Thus, the private key value d should be
// output to (bitlength(n-1)+7)>>3 octets.
n := curve.Params().N
octetLength := (new(big.Int).Sub(n, big.NewInt(1)).BitLen() + 7) >> 3
dByteLength := len(dBytes)
if dByteLength != octetLength {
return nil, fmt.Errorf("invalid number of octets: got %d, should be %d", dByteLength, octetLength)
}
return new(big.Int).SetBytes(dBytes), nil
}
func parseRSAModulusParam(nB64Url string) (*big.Int, error) {
nBytes, err := joseBase64UrlDecode(nB64Url)
if err != nil {
return nil, fmt.Errorf("invalid base64 URL encoding: %s", err)
}
return new(big.Int).SetBytes(nBytes), nil
}
func serializeRSAPublicExponentParam(e int) []byte {
// We MUST use the minimum number of octets to represent E.
// E is supposed to be 65537 for performance and security reasons
// and is what golang's rsa package generates, but it might be
// different if imported from some other generator.
buf := make([]byte, 4)
binary.BigEndian.PutUint32(buf, uint32(e))
var i int
for i = 0; i < 8; i++ {
if buf[i] != 0 {
break
}
}
return buf[i:]
}
func parseRSAPublicExponentParam(eB64Url string) (int, error) {
eBytes, err := joseBase64UrlDecode(eB64Url)
if err != nil {
return 0, fmt.Errorf("invalid base64 URL encoding: %s", err)
}
// Only the minimum number of bytes were used to represent E, but
// binary.BigEndian.Uint32 expects at least 4 bytes, so we need
// to add zero padding if necassary.
byteLen := len(eBytes)
buf := make([]byte, 4-byteLen, 4)
eBytes = append(buf, eBytes...)
return int(binary.BigEndian.Uint32(eBytes)), nil
}
func parseRSAPrivateKeyParamFromMap(m map[string]interface{}, key string) (*big.Int, error) {
b64Url, err := stringFromMap(m, key)
if err != nil {
return nil, err
}
paramBytes, err := joseBase64UrlDecode(b64Url)
if err != nil {
return nil, fmt.Errorf("invaled base64 URL encoding: %s", err)
}
return new(big.Int).SetBytes(paramBytes), nil
}
func createPemBlock(name string, derBytes []byte, headers map[string]interface{}) (*pem.Block, error) {
pemBlock := &pem.Block{Type: name, Bytes: derBytes, Headers: map[string]string{}}
for k, v := range headers {
switch val := v.(type) {
case string:
pemBlock.Headers[k] = val
case []string:
if k == "hosts" {
pemBlock.Headers[k] = strings.Join(val, ",")
} else {
// Return error, non-encodable type
}
default:
// Return error, non-encodable type
}
}
return pemBlock, nil
}
func pubKeyFromPEMBlock(pemBlock *pem.Block) (PublicKey, error) {
cryptoPublicKey, err := x509.ParsePKIXPublicKey(pemBlock.Bytes)
if err != nil {
return nil, fmt.Errorf("unable to decode Public Key PEM data: %s", err)
}
pubKey, err := FromCryptoPublicKey(cryptoPublicKey)
if err != nil {
return nil, err
}
addPEMHeadersToKey(pemBlock, pubKey)
return pubKey, nil
}
func addPEMHeadersToKey(pemBlock *pem.Block, pubKey PublicKey) {
for key, value := range pemBlock.Headers {
var safeVal interface{}
if key == "hosts" {
safeVal = strings.Split(value, ",")
} else {
safeVal = value
}
pubKey.AddExtendedField(key, safeVal)
}
}
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