working on removing dependency on cfssl.

certlib/der_helpers.go

@@ -0,0 +1,75 @@
+package certlib
+
+// Originally from CFSSL, mostly written by me originally, and licensed under:
+
+/*
+Copyright (c) 2014 CloudFlare Inc.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+
+Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+// I've modified it for use in my own code e.g. by removing the CFSSL errors
+// and replacing them with sane ones.
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/rsa"
+	"crypto/x509"
+	"fmt"
+
+	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
+)
+
+// ParsePrivateKeyDER parses a PKCS #1, PKCS #8, ECDSA, or Ed25519 DER-encoded
+// private key. The key must not be in PEM format. If an error is returned, it
+// may contain information about the private key, so care should be taken when
+// displaying it directly.
+func ParsePrivateKeyDER(keyDER []byte) (key crypto.Signer, err error) {
+	generalKey, err := x509.ParsePKCS8PrivateKey(keyDER)
+	if err != nil {
+		generalKey, err = x509.ParsePKCS1PrivateKey(keyDER)
+		if err != nil {
+			generalKey, err = x509.ParseECPrivateKey(keyDER)
+			if err != nil {
+				generalKey, err = ParseEd25519PrivateKey(keyDER)
+				if err != nil {
+					return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, err)
+				}
+			}
+		}
+	}
+
+	switch generalKey := generalKey.(type) {
+	case *rsa.PrivateKey:
+		return generalKey, nil
+	case *ecdsa.PrivateKey:
+		return generalKey, nil
+	case ed25519.PrivateKey:
+		return generalKey, nil
+	default:
+		return nil, certerr.ParsingError(certerr.ErrorSourcePrivateKey, fmt.Errorf("unknown key type %t", generalKey))
+	}
+}