添加 github.com/pion/dtls 代码

dtls-2.0.9/pkg/crypto/signaturehash/signaturehash.go

@@ -0,0 +1,93 @@
+// Package signaturehash provides the SignatureHashAlgorithm as defined in TLS 1.2
+package signaturehash
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"crypto/tls"
+
+	"github.com/pion/dtls/v2/pkg/crypto/hash"
+	"github.com/pion/dtls/v2/pkg/crypto/signature"
+	"golang.org/x/xerrors"
+)
+
+// Algorithm is a signature/hash algorithm pairs which may be used in
+// digital signatures.
+//
+// https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
+type Algorithm struct {
+	Hash      hash.Algorithm
+	Signature signature.Algorithm
+}
+
+// Algorithms are all the know SignatureHash Algorithms
+func Algorithms() []Algorithm {
+	return []Algorithm{
+		{hash.SHA256, signature.ECDSA},
+		{hash.SHA384, signature.ECDSA},
+		{hash.SHA512, signature.ECDSA},
+		{hash.SHA256, signature.RSA},
+		{hash.SHA384, signature.RSA},
+		{hash.SHA512, signature.RSA},
+		{hash.Ed25519, signature.Ed25519},
+	}
+}
+
+// SelectSignatureScheme returns most preferred and compatible scheme.
+func SelectSignatureScheme(sigs []Algorithm, privateKey crypto.PrivateKey) (Algorithm, error) {
+	for _, ss := range sigs {
+		if ss.isCompatible(privateKey) {
+			return ss, nil
+		}
+	}
+	return Algorithm{}, errNoAvailableSignatureSchemes
+}
+
+// isCompatible checks that given private key is compatible with the signature scheme.
+func (a *Algorithm) isCompatible(privateKey crypto.PrivateKey) bool {
+	switch privateKey.(type) {
+	case ed25519.PrivateKey:
+		return a.Signature == signature.Ed25519
+	case *ecdsa.PrivateKey:
+		return a.Signature == signature.ECDSA
+	case *rsa.PrivateKey:
+		return a.Signature == signature.RSA
+	default:
+		return false
+	}
+}
+
+// ParseSignatureSchemes translates []tls.SignatureScheme to []signatureHashAlgorithm.
+// It returns default signature scheme list if no SignatureScheme is passed.
+func ParseSignatureSchemes(sigs []tls.SignatureScheme, insecureHashes bool) ([]Algorithm, error) {
+	if len(sigs) == 0 {
+		return Algorithms(), nil
+	}
+	out := []Algorithm{}
+	for _, ss := range sigs {
+		sig := signature.Algorithm(ss & 0xFF)
+		if _, ok := signature.Algorithms()[sig]; !ok {
+			return nil,
+				xerrors.Errorf("SignatureScheme %04x: %w", ss, errInvalidSignatureAlgorithm)
+		}
+		h := hash.Algorithm(ss >> 8)
+		if _, ok := hash.Algorithms()[h]; !ok || (ok && h == hash.None) {
+			return nil, xerrors.Errorf("SignatureScheme %04x: %w", ss, errInvalidHashAlgorithm)
+		}
+		if h.Insecure() && !insecureHashes {
+			continue
+		}
+		out = append(out, Algorithm{
+			Hash:      h,
+			Signature: sig,
+		})
+	}
+
+	if len(out) == 0 {
+		return nil, errNoAvailableSignatureSchemes
+	}
+
+	return out, nil
+}