Vendor main dependencies.

vendor/github.com/xenolf/lego/acme/crypto.go

@@ -0,0 +1,347 @@
+package acme
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"strings"
+	"time"
+
+	"encoding/asn1"
+
+	"golang.org/x/crypto/ocsp"
+)
+
+// KeyType represents the key algo as well as the key size or curve to use.
+type KeyType string
+type derCertificateBytes []byte
+
+// Constants for all key types we support.
+const (
+	EC256   = KeyType("P256")
+	EC384   = KeyType("P384")
+	RSA2048 = KeyType("2048")
+	RSA4096 = KeyType("4096")
+	RSA8192 = KeyType("8192")
+)
+
+const (
+	// OCSPGood means that the certificate is valid.
+	OCSPGood = ocsp.Good
+	// OCSPRevoked means that the certificate has been deliberately revoked.
+	OCSPRevoked = ocsp.Revoked
+	// OCSPUnknown means that the OCSP responder doesn't know about the certificate.
+	OCSPUnknown = ocsp.Unknown
+	// OCSPServerFailed means that the OCSP responder failed to process the request.
+	OCSPServerFailed = ocsp.ServerFailed
+)
+
+// Constants for OCSP must staple
+var (
+	tlsFeatureExtensionOID = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 24}
+	ocspMustStapleFeature  = []byte{0x30, 0x03, 0x02, 0x01, 0x05}
+)
+
+// GetOCSPForCert takes a PEM encoded cert or cert bundle returning the raw OCSP response,
+// the parsed response, and an error, if any. The returned []byte can be passed directly
+// into the OCSPStaple property of a tls.Certificate. If the bundle only contains the
+// issued certificate, this function will try to get the issuer certificate from the
+// IssuingCertificateURL in the certificate. If the []byte and/or ocsp.Response return
+// values are nil, the OCSP status may be assumed OCSPUnknown.
+func GetOCSPForCert(bundle []byte) ([]byte, *ocsp.Response, error) {
+	certificates, err := parsePEMBundle(bundle)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// We expect the certificate slice to be ordered downwards the chain.
+	// SRV CRT -> CA. We need to pull the leaf and issuer certs out of it,
+	// which should always be the first two certificates. If there's no
+	// OCSP server listed in the leaf cert, there's nothing to do. And if
+	// we have only one certificate so far, we need to get the issuer cert.
+	issuedCert := certificates[0]
+	if len(issuedCert.OCSPServer) == 0 {
+		return nil, nil, errors.New("no OCSP server specified in cert")
+	}
+	if len(certificates) == 1 {
+		// TODO: build fallback. If this fails, check the remaining array entries.
+		if len(issuedCert.IssuingCertificateURL) == 0 {
+			return nil, nil, errors.New("no issuing certificate URL")
+		}
+
+		resp, err := httpGet(issuedCert.IssuingCertificateURL[0])
+		if err != nil {
+			return nil, nil, err
+		}
+		defer resp.Body.Close()
+
+		issuerBytes, err := ioutil.ReadAll(limitReader(resp.Body, 1024*1024))
+		if err != nil {
+			return nil, nil, err
+		}
+
+		issuerCert, err := x509.ParseCertificate(issuerBytes)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// Insert it into the slice on position 0
+		// We want it ordered right SRV CRT -> CA
+		certificates = append(certificates, issuerCert)
+	}
+	issuerCert := certificates[1]
+
+	// Finally kick off the OCSP request.
+	ocspReq, err := ocsp.CreateRequest(issuedCert, issuerCert, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	reader := bytes.NewReader(ocspReq)
+	req, err := httpPost(issuedCert.OCSPServer[0], "application/ocsp-request", reader)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer req.Body.Close()
+
+	ocspResBytes, err := ioutil.ReadAll(limitReader(req.Body, 1024*1024))
+	ocspRes, err := ocsp.ParseResponse(ocspResBytes, issuerCert)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return ocspResBytes, ocspRes, nil
+}
+
+func getKeyAuthorization(token string, key interface{}) (string, error) {
+	var publicKey crypto.PublicKey
+	switch k := key.(type) {
+	case *ecdsa.PrivateKey:
+		publicKey = k.Public()
+	case *rsa.PrivateKey:
+		publicKey = k.Public()
+	}
+
+	// Generate the Key Authorization for the challenge
+	jwk := keyAsJWK(publicKey)
+	if jwk == nil {
+		return "", errors.New("Could not generate JWK from key.")
+	}
+	thumbBytes, err := jwk.Thumbprint(crypto.SHA256)
+	if err != nil {
+		return "", err
+	}
+
+	// unpad the base64URL
+	keyThumb := base64.URLEncoding.EncodeToString(thumbBytes)
+	index := strings.Index(keyThumb, "=")
+	if index != -1 {
+		keyThumb = keyThumb[:index]
+	}
+
+	return token + "." + keyThumb, nil
+}
+
+// parsePEMBundle parses a certificate bundle from top to bottom and returns
+// a slice of x509 certificates. This function will error if no certificates are found.
+func parsePEMBundle(bundle []byte) ([]*x509.Certificate, error) {
+	var certificates []*x509.Certificate
+	var certDERBlock *pem.Block
+
+	for {
+		certDERBlock, bundle = pem.Decode(bundle)
+		if certDERBlock == nil {
+			break
+		}
+
+		if certDERBlock.Type == "CERTIFICATE" {
+			cert, err := x509.ParseCertificate(certDERBlock.Bytes)
+			if err != nil {
+				return nil, err
+			}
+			certificates = append(certificates, cert)
+		}
+	}
+
+	if len(certificates) == 0 {
+		return nil, errors.New("No certificates were found while parsing the bundle.")
+	}
+
+	return certificates, nil
+}
+
+func parsePEMPrivateKey(key []byte) (crypto.PrivateKey, error) {
+	keyBlock, _ := pem.Decode(key)
+
+	switch keyBlock.Type {
+	case "RSA PRIVATE KEY":
+		return x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	case "EC PRIVATE KEY":
+		return x509.ParseECPrivateKey(keyBlock.Bytes)
+	default:
+		return nil, errors.New("Unknown PEM header value")
+	}
+}
+
+func generatePrivateKey(keyType KeyType) (crypto.PrivateKey, error) {
+
+	switch keyType {
+	case EC256:
+		return ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	case EC384:
+		return ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	case RSA2048:
+		return rsa.GenerateKey(rand.Reader, 2048)
+	case RSA4096:
+		return rsa.GenerateKey(rand.Reader, 4096)
+	case RSA8192:
+		return rsa.GenerateKey(rand.Reader, 8192)
+	}
+
+	return nil, fmt.Errorf("Invalid KeyType: %s", keyType)
+}
+
+func generateCsr(privateKey crypto.PrivateKey, domain string, san []string, mustStaple bool) ([]byte, error) {
+	template := x509.CertificateRequest{
+		Subject: pkix.Name{
+			CommonName: domain,
+		},
+	}
+
+	if len(san) > 0 {
+		template.DNSNames = san
+	}
+
+	if mustStaple {
+		template.ExtraExtensions = append(template.ExtraExtensions, pkix.Extension{
+			Id:    tlsFeatureExtensionOID,
+			Value: ocspMustStapleFeature,
+		})
+	}
+
+	return x509.CreateCertificateRequest(rand.Reader, &template, privateKey)
+}
+
+func pemEncode(data interface{}) []byte {
+	var pemBlock *pem.Block
+	switch key := data.(type) {
+	case *ecdsa.PrivateKey:
+		keyBytes, _ := x509.MarshalECPrivateKey(key)
+		pemBlock = &pem.Block{Type: "EC PRIVATE KEY", Bytes: keyBytes}
+	case *rsa.PrivateKey:
+		pemBlock = &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
+		break
+	case *x509.CertificateRequest:
+		pemBlock = &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: key.Raw}
+		break
+	case derCertificateBytes:
+		pemBlock = &pem.Block{Type: "CERTIFICATE", Bytes: []byte(data.(derCertificateBytes))}
+	}
+
+	return pem.EncodeToMemory(pemBlock)
+}
+
+func pemDecode(data []byte) (*pem.Block, error) {
+	pemBlock, _ := pem.Decode(data)
+	if pemBlock == nil {
+		return nil, fmt.Errorf("Pem decode did not yield a valid block. Is the certificate in the right format?")
+	}
+
+	return pemBlock, nil
+}
+
+func pemDecodeTox509(pem []byte) (*x509.Certificate, error) {
+	pemBlock, err := pemDecode(pem)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificate(pemBlock.Bytes)
+}
+
+func pemDecodeTox509CSR(pem []byte) (*x509.CertificateRequest, error) {
+	pemBlock, err := pemDecode(pem)
+	if pemBlock == nil {
+		return nil, err
+	}
+
+	if pemBlock.Type != "CERTIFICATE REQUEST" {
+		return nil, fmt.Errorf("PEM block is not a certificate request")
+	}
+
+	return x509.ParseCertificateRequest(pemBlock.Bytes)
+}
+
+// GetPEMCertExpiration returns the "NotAfter" date of a PEM encoded certificate.
+// The certificate has to be PEM encoded. Any other encodings like DER will fail.
+func GetPEMCertExpiration(cert []byte) (time.Time, error) {
+	pemBlock, err := pemDecode(cert)
+	if pemBlock == nil {
+		return time.Time{}, err
+	}
+
+	return getCertExpiration(pemBlock.Bytes)
+}
+
+// getCertExpiration returns the "NotAfter" date of a DER encoded certificate.
+func getCertExpiration(cert []byte) (time.Time, error) {
+	pCert, err := x509.ParseCertificate(cert)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	return pCert.NotAfter, nil
+}
+
+func generatePemCert(privKey *rsa.PrivateKey, domain string) ([]byte, error) {
+	derBytes, err := generateDerCert(privKey, time.Time{}, domain)
+	if err != nil {
+		return nil, err
+	}
+
+	return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derBytes}), nil
+}
+
+func generateDerCert(privKey *rsa.PrivateKey, expiration time.Time, domain string) ([]byte, error) {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return nil, err
+	}
+
+	if expiration.IsZero() {
+		expiration = time.Now().Add(365)
+	}
+
+	template := x509.Certificate{
+		SerialNumber: serialNumber,
+		Subject: pkix.Name{
+			CommonName: "ACME Challenge TEMP",
+		},
+		NotBefore: time.Now(),
+		NotAfter:  expiration,
+
+		KeyUsage:              x509.KeyUsageKeyEncipherment,
+		BasicConstraintsValid: true,
+		DNSNames:              []string{domain},
+	}
+
+	return x509.CreateCertificate(rand.Reader, &template, &template, &privKey.PublicKey, privKey)
+}
+
+func limitReader(rd io.ReadCloser, numBytes int64) io.ReadCloser {
+	return http.MaxBytesReader(nil, rd, numBytes)
+}