1 files changed, 221 insertions, 0 deletions
diff --git a/vendor/github.com/pion/dtls/v2/crypto.go b/vendor/github.com/pion/dtls/v2/crypto.go
new file mode 100644
index 0000000..768ee47
--- /dev/null
+++ b/vendor/github.com/pion/dtls/v2/crypto.go
@@ -0,0 +1,221 @@
+package dtls
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/asn1"
+	"encoding/binary"
+	"math/big"
+	"time"
+
+	"github.com/pion/dtls/v2/pkg/crypto/elliptic"
+	"github.com/pion/dtls/v2/pkg/crypto/hash"
+)
+
+type ecdsaSignature struct {
+	R, S *big.Int
+}
+
+func valueKeyMessage(clientRandom, serverRandom, publicKey []byte, namedCurve elliptic.Curve) []byte {
+	serverECDHParams := make([]byte, 4)
+	serverECDHParams[0] = 3 // named curve
+	binary.BigEndian.PutUint16(serverECDHParams[1:], uint16(namedCurve))
+	serverECDHParams[3] = byte(len(publicKey))
+
+	plaintext := []byte{}
+	plaintext = append(plaintext, clientRandom...)
+	plaintext = append(plaintext, serverRandom...)
+	plaintext = append(plaintext, serverECDHParams...)
+	plaintext = append(plaintext, publicKey...)
+
+	return plaintext
+}
+
+// If the client provided a "signature_algorithms" extension, then all
+// certificates provided by the server MUST be signed by a
+// hash/signature algorithm pair that appears in that extension
+//
+// https://tools.ietf.org/html/rfc5246#section-7.4.2
+func generateKeySignature(clientRandom, serverRandom, publicKey []byte, namedCurve elliptic.Curve, privateKey crypto.PrivateKey, hashAlgorithm hash.Algorithm) ([]byte, error) {
+	msg := valueKeyMessage(clientRandom, serverRandom, publicKey, namedCurve)
+	switch p := privateKey.(type) {
+	case ed25519.PrivateKey:
+		// https://crypto.stackexchange.com/a/55483
+		return p.Sign(rand.Reader, msg, crypto.Hash(0))
+	case *ecdsa.PrivateKey:
+		hashed := hashAlgorithm.Digest(msg)
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	case *rsa.PrivateKey:
+		hashed := hashAlgorithm.Digest(msg)
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	}
+
+	return nil, errKeySignatureGenerateUnimplemented
+}
+
+func verifyKeySignature(message, remoteKeySignature []byte, hashAlgorithm hash.Algorithm, rawCertificates [][]byte) error { //nolint:dupl
+	if len(rawCertificates) == 0 {
+		return errLengthMismatch
+	}
+	certificate, err := x509.ParseCertificate(rawCertificates[0])
+	if err != nil {
+		return err
+	}
+
+	switch p := certificate.PublicKey.(type) {
+	case ed25519.PublicKey:
+		if ok := ed25519.Verify(p, message, remoteKeySignature); !ok {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *ecdsa.PublicKey:
+		ecdsaSig := &ecdsaSignature{}
+		if _, err := asn1.Unmarshal(remoteKeySignature, ecdsaSig); err != nil {
+			return err
+		}
+		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
+			return errInvalidECDSASignature
+		}
+		hashed := hashAlgorithm.Digest(message)
+		if !ecdsa.Verify(p, hashed, ecdsaSig.R, ecdsaSig.S) {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *rsa.PublicKey:
+		switch certificate.SignatureAlgorithm {
+		case x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
+			hashed := hashAlgorithm.Digest(message)
+			return rsa.VerifyPKCS1v15(p, hashAlgorithm.CryptoHash(), hashed, remoteKeySignature)
+		default:
+			return errKeySignatureVerifyUnimplemented
+		}
+	}
+
+	return errKeySignatureVerifyUnimplemented
+}
+
+// If the server has sent a CertificateRequest message, the client MUST send the Certificate
+// message.  The ClientKeyExchange message is now sent, and the content
+// of that message will depend on the public key algorithm selected
+// between the ClientHello and the ServerHello.  If the client has sent
+// a certificate with signing ability, a digitally-signed
+// CertificateVerify message is sent to explicitly verify possession of
+// the private key in the certificate.
+// https://tools.ietf.org/html/rfc5246#section-7.3
+func generateCertificateVerify(handshakeBodies []byte, privateKey crypto.PrivateKey, hashAlgorithm hash.Algorithm) ([]byte, error) {
+	h := sha256.New()
+	if _, err := h.Write(handshakeBodies); err != nil {
+		return nil, err
+	}
+	hashed := h.Sum(nil)
+
+	switch p := privateKey.(type) {
+	case ed25519.PrivateKey:
+		// https://crypto.stackexchange.com/a/55483
+		return p.Sign(rand.Reader, hashed, crypto.Hash(0))
+	case *ecdsa.PrivateKey:
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	case *rsa.PrivateKey:
+		return p.Sign(rand.Reader, hashed, hashAlgorithm.CryptoHash())
+	}
+
+	return nil, errInvalidSignatureAlgorithm
+}
+
+func verifyCertificateVerify(handshakeBodies []byte, hashAlgorithm hash.Algorithm, remoteKeySignature []byte, rawCertificates [][]byte) error { //nolint:dupl
+	if len(rawCertificates) == 0 {
+		return errLengthMismatch
+	}
+	certificate, err := x509.ParseCertificate(rawCertificates[0])
+	if err != nil {
+		return err
+	}
+
+	switch p := certificate.PublicKey.(type) {
+	case ed25519.PublicKey:
+		if ok := ed25519.Verify(p, handshakeBodies, remoteKeySignature); !ok {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *ecdsa.PublicKey:
+		ecdsaSig := &ecdsaSignature{}
+		if _, err := asn1.Unmarshal(remoteKeySignature, ecdsaSig); err != nil {
+			return err
+		}
+		if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 {
+			return errInvalidECDSASignature
+		}
+		hash := hashAlgorithm.Digest(handshakeBodies)
+		if !ecdsa.Verify(p, hash, ecdsaSig.R, ecdsaSig.S) {
+			return errKeySignatureMismatch
+		}
+		return nil
+	case *rsa.PublicKey:
+		switch certificate.SignatureAlgorithm {
+		case x509.SHA1WithRSA, x509.SHA256WithRSA, x509.SHA384WithRSA, x509.SHA512WithRSA:
+			hash := hashAlgorithm.Digest(handshakeBodies)
+			return rsa.VerifyPKCS1v15(p, hashAlgorithm.CryptoHash(), hash, remoteKeySignature)
+		default:
+			return errKeySignatureVerifyUnimplemented
+		}
+	}
+
+	return errKeySignatureVerifyUnimplemented
+}
+
+func loadCerts(rawCertificates [][]byte) ([]*x509.Certificate, error) {
+	if len(rawCertificates) == 0 {
+		return nil, errLengthMismatch
+	}
+
+	certs := make([]*x509.Certificate, 0, len(rawCertificates))
+	for _, rawCert := range rawCertificates {
+		cert, err := x509.ParseCertificate(rawCert)
+		if err != nil {
+			return nil, err
+		}
+		certs = append(certs, cert)
+	}
+	return certs, nil
+}
+
+func verifyClientCert(rawCertificates [][]byte, roots *x509.CertPool) (chains [][]*x509.Certificate, err error) {
+	certificate, err := loadCerts(rawCertificates)
+	if err != nil {
+		return nil, err
+	}
+	intermediateCAPool := x509.NewCertPool()
+	for _, cert := range certificate[1:] {
+		intermediateCAPool.AddCert(cert)
+	}
+	opts := x509.VerifyOptions{
+		Roots:         roots,
+		CurrentTime:   time.Now(),
+		Intermediates: intermediateCAPool,
+		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+	}
+	return certificate[0].Verify(opts)
+}
+
+func verifyServerCert(rawCertificates [][]byte, roots *x509.CertPool, serverName string) (chains [][]*x509.Certificate, err error) {
+	certificate, err := loadCerts(rawCertificates)
+	if err != nil {
+		return nil, err
+	}
+	intermediateCAPool := x509.NewCertPool()
+	for _, cert := range certificate[1:] {
+		intermediateCAPool.AddCert(cert)
+	}
+	opts := x509.VerifyOptions{
+		Roots:         roots,
+		CurrentTime:   time.Now(),
+		DNSName:       serverName,
+		Intermediates: intermediateCAPool,
+	}
+	return certificate[0].Verify(opts)
+}